tag:theconversation.com,2011:/global/topics/carcinogen-5510/articlesCarcinogen – The Conversation2023-08-10T20:00:53Ztag:theconversation.com,2011:article/2104622023-08-10T20:00:53Z2023-08-10T20:00:53ZWhat’s in vapes? Toxins, heavy metals, maybe radioactive polonium<figure><img src="https://images.theconversation.com/files/541174/original/file-20230804-29-77kck2.jpg?ixlib=rb-1.1.0&rect=1%2C1%2C997%2C664&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-girl-smokes-disposable-electronic-cigarette-1943062066">Shutterstock</a></span></figcaption></figure><p>If you asked me what’s in e-cigarettes, disposable vapes or e-liquids, my short answer would be “we don’t fully know”.</p>
<p>The huge and increasing range of products and flavours on the market, changes to ingredients when they are heated or interact with each other, and inadequate labelling make this a complicated question to answer.</p>
<p><a href="https://www.annualreviews.org/doi/pdf/10.1146/annurev-anchem-061318-115329">Analytical chemistry</a>, including <a href="https://www.mja.com.au/journal/2022/216/1/chemical-analysis-fresh-and-aged-australian-e-cigarette-liquids">my own team’s research</a>, gives some answers. But understanding the health impacts adds another level of complexity. E-cigarettes’ risk to health varies depending on <a href="https://pubs.acs.org/doi/abs/10.1021/acs.chemrestox.1c00070">many factors</a> including which device or flavours are used, and how people use them.</p>
<p>So vapers just don’t know what they’re inhaling and cannot be certain of the health impacts.</p>
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<strong>
Read more:
<a href="https://theconversation.com/no-vapes-arent-95-less-harmful-than-cigarettes-heres-how-this-decade-old-myth-took-off-203039">No, vapes aren't 95% less harmful than cigarettes. Here's how this decade-old myth took off</a>
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</p>
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<h2>What do we know?</h2>
<p>Despite these complexities, there are some consistencies between what different laboratories find.</p>
<p>Ingredients include nicotine, flavouring chemicals, and the liquids that carry them – primarily propylene glycol and glycerine.</p>
<p><a href="https://www.industrialchemicals.gov.au/sites/default/files/2020-08/Non-nicotine%20liquids%20for%20e-cigarette%20devices%20in%20Australia%20chemistry%20and%20health%20concerns%20%5BPDF%201.21%20MB%5D.pdf">Concerningly</a>, we also find volatile organic compounds, particulate matter and carcinogens (agents that can cause cancer), many of which we know are harmful. </p>
<p>Our <a href="https://www.mja.com.au/journal/2019/210/3/nicotine-and-other-potentially-harmful-compounds-nicotine-free-e-cigarette">previous</a> <a href="https://www.mja.com.au/journal/2022/216/1/chemical-analysis-fresh-and-aged-australian-e-cigarette-liquids">research</a> also found 2-chlorophenol in about half of e-liquids users buy to top-up re-fillable e-cigarettes. This is one example of a chemical with no valid reason to be there. Globally, it’s <a href="https://pubchem.ncbi.nlm.nih.gov/compound/2-Chlorophenol#section=Hazard-Classes-and-Categories">classified</a> as “harmful if inhaled”. Its presence is likely due to contamination during manufacturing.</p>
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Read more:
<a href="https://theconversation.com/many-e-cigarette-vaping-liquids-contain-toxic-chemicals-new-australian-research-169615">Many e-cigarette vaping liquids contain toxic chemicals: new Australian research</a>
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<h2>How about polonium?</h2>
<p>One potential ingredient that has been in the news in recent weeks is radioactive polonium-210, the same substance used to <a href="https://theconversation.com/litvinenko-poisoning-polonium-explained-53514">assassinate</a> former Russian spy Alexander Litvinenko in 2006. The Queensland government is <a href="https://www.abc.net.au/news/2023-07-26/queensland-scientists-test-vapes-for-polonium-210/102564282">now testing</a> vapes for it.</p>
<p>Polonium-210 <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9207432/">can be found</a> in traditional cigarettes and other tobacco products. That’s because tobacco plants <a href="https://www.science.org/doi/abs/10.1126/science.153.3738.880">absorb it</a> and other radioactive materials from the soil, air and high-phosphate fertiliser.</p>
<p>Whether polonium-210 is found in aerosols produced by e-cigarettes remains to be seen. Although it is feasible if the glycerine in e-liquids comes from plants and similar fertilisers are used to grow them.</p>
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Read more:
<a href="https://theconversation.com/litvinenko-poisoning-polonium-explained-53514">Litvinenko poisoning: polonium explained</a>
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<h2>It’s not just the ingredients</h2>
<p>Aside from their ingredients, the materials e-cigarette devices are made from can end up in our bodies.</p>
<p><a href="https://ehp.niehs.nih.gov/doi/full/10.1289/EHP2175">Toxic metals</a> and <a href="https://ehp.niehs.nih.gov/doi/full/10.1289/EHP5686">related substances</a> such as arsenic, lead, chromium and nickel can be detected in both e-liquids and vapers’ urine, saliva and blood.</p>
<p>These substances can pose serious health risks (such as being carcinogenic). They can leach from several parts of an e-cigarette, including the heating coil, wires and soldered joints.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&rect=1%2C0%2C997%2C655&q=45&auto=format&w=1000&fit=clip"><img alt="Colourful, disposable vapes on a blue background" src="https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&rect=1%2C0%2C997%2C655&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=394&fit=crop&dpr=1 600w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=394&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=394&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=495&fit=crop&dpr=1 754w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=495&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/541152/original/file-20230804-21381-h5ifyj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=495&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Chemicals from the device itself can end up in our blood, urine and saliva.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/set-colorful-disposable-electronic-cigarettes-on-2065547126">Shutterstock</a></span>
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Read more:
<a href="https://theconversation.com/we-asked-over-700-teens-where-they-bought-their-vapes-heres-what-they-said-190669">We asked over 700 teens where they bought their vapes. Here's what they said</a>
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<h2>That’s not all</h2>
<p>The process of heating e-liquids to create an inhalable aerosol also changes their chemical make-up to produce <a href="https://pubs.acs.org/doi/10.1021/acs.chemrestox.9b00410">degradation</a> <a href="https://pubs.acs.org/doi/10.1021/acs.est.7b02205">products</a>. </p>
<p>These include:</p>
<ul>
<li><p>formaldehyde (a substance used to embalm dead bodies)</p></li>
<li><p>acetaldehyde (a key substance that contributes to a hangover after drinking alcohol)</p></li>
<li><p>acrolein (used as a chemical weapon in the first world war and now used as a herbicide).</p></li>
</ul>
<p>These chemicals are <a href="https://www.mdpi.com/2305-6304/10/12/714">often detected</a> in <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6129974">e-cigarette samples</a>. However due to different devices and how the samples are collected, the <a href="https://ehjournal.biomedcentral.com/articles/10.1186/s12940-017-0249-x">levels measured</a> <a href="https://pubs.acs.org/doi/10.1021/acs.est.7b02205">vary widely</a> between studies.</p>
<p>Often, the levels are very low, leading to proponents of vaping arguing e-cigarettes are far safer than tobacco smoking. </p>
<p>But this argument does not acknowledge that many e-cigarette users (particularly adolescents) <a href="https://www.tobaccoinaustralia.org.au/chapter-18-e-cigarettes/18-3-extent">were or are not cigarette smokers</a>, meaning a better comparison is between e-cigarette use and breathing “fresh” air. </p>
<p>An e-cigarette user is undoubtedly exposed to more toxins and harmful substances than a non-smoker. People who buy tobacco cigarettes are also confronted with a plethora of warnings about the hazards of smoking, while vapers generally are not.</p>
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Read more:
<a href="https://theconversation.com/sex-and-lies-are-used-to-sell-vapes-online-even-we-were-surprised-at-the-marketing-tactics-we-found-200446">Sex and lies are used to sell vapes online. Even we were surprised at the marketing tactics we found</a>
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<h2>How about labelling?</h2>
<p>This leads to another reason why it’s impossible to tell what is in vapes – the lack of information, including warnings, <a href="https://www.legislation.gov.au/Details/F2021L00595">on the label</a>.</p>
<p>Even if labels are present, they don’t always reflect what’s in the product. Nicotine concentration of e-liquids is often quite different to what is on the label, and “nicotine-free” e-liquids often <a href="https://journal.chestnet.org/article/S0012-3692(20)30134-3/fulltext">contain nicotine</a>.</p>
<p>Products are also labelled with generic flavour names such as “berry” or “tobacco”. But there is no way for a user to know what chemicals have been added to make those “berry” or “tobacco” flavours or the changes in these chemicals that may occur with heating and/or interacting with other ingredients and the device components. “Berry” <a href="https://tobaccocontrol.bmj.com/content/30/2/185">flavour</a> alone could be made from <a href="https://tobaccocontrol.bmj.com/content/tobaccocontrol/suppl/2020/02/10/tobaccocontrol-2019-055447.DC1/tobaccocontrol-2019-055447supp001_data_supplement.pdf">more than 35</a> different chemicals. </p>
<p>Flavouring chemicals may be “food grade” or classified as safe-to-eat. However mixing them into e-liquids, heating and inhaling them is a very different type of exposure, compared to eating them.</p>
<p>One example is benzaldehyde (an almond flavouring). When this is inhaled, it <a href="https://pubs.acs.org/doi/abs/10.1021/acs.chemrestox.9b00171">impairs</a> the <a href="https://www.sciencedirect.com/science/article/pii/S2214750023000380">immune function</a> of lung cells. This could potentially reduce a vaper’s ability to deal with other inhaled toxins, or respiratory infections. </p>
<p>Benzaldehyde is one of only <a href="https://www.legislation.gov.au/Details/F2021L00595">eight</a> banned e-liquid ingredients in Australia. The list is so short because we don’t have enough information on the health effects if inhaled of other flavouring chemicals, and their interactions with other e-liquid ingredients.</p>
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<h2>Where to next?</h2>
<p>For us to better assess the health risks of vapes, we need to learn more about:</p>
<ul>
<li><p>what happens when flavour chemicals are heated and inhaled</p></li>
<li><p>the interactions between different e-liquid ingredients</p></li>
<li><p>what other contaminants may be present in e-liquids</p></li>
<li><p>new, potentially harmful, substances in e-cigarettes.</p></li>
</ul>
<p>Finally, we need to know more about how people use e-cigarettes so we can better understand and quantify the health risks in the real world.</p><img src="https://counter.theconversation.com/content/210462/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alexander Larcombe has previously received funding for e-cigarette research from the National Health and Medical Research Council, Lung Foundation Australia, Minderoo Foundation, Health Department of Western Australia and Asthma Foundation of Western Australia. The funders played no role in the conduct of the research. He is also a member of the Australian Council on Smoking and Health (ACOSH).</span></em></p>It’s not just the ingredients we should be concerned about. The devices themselves release chemicals that end up in our blood and urine.Alexander Larcombe, Associate Professor and Head of Respiratory Environmental Health, Telethon Kids InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2079272023-08-06T20:00:33Z2023-08-06T20:00:33ZIs red meat bad for you? And does it make a difference if it’s a processed burger or a lean steak?<figure><img src="https://images.theconversation.com/files/538681/original/file-20230721-6326-7bnydt.jpg?ixlib=rb-1.1.0&rect=8%2C8%2C5742%2C3819&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>A juicy burger is a staple in many Australians’ diet. Yet research shows regularly eating red meat can increase your risk of developing <a href="https://academic.oup.com/eurheartj/advance-article/doi/10.1093/eurheartj/ehad336/7188739?searchresult=1">type 2 diabetes, heart disease</a> and <a href="https://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(15)00444-1/fulltext">certain cancers</a>.</p>
<p>But is eating a beef burger worse for your health than eating a lean grass-fed steak? And how much red meat should we really be eating?</p>
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Read more:
<a href="https://theconversation.com/talking-about-eating-less-red-and-processed-meat-provokes-strong-feelings-thats-why-this-new-evidence-based-report-is-welcome-209234">Talking about eating less red and processed meat provokes strong feelings. That's why this new evidence-based report is welcome</a>
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<h2>Types of red meat</h2>
<p>First of all, it’s good to clarify that <a href="https://www.who.int/publications/i/item/9789240074828">red meat</a> refers to all mammalian muscle meat. So that includes beef, lamb, pork, veal, mutton and goat. </p>
<p>Then we can distinguish red meat types by how the animal has been raised and how the meat is processed. Here are some key terms to know.</p>
<p>Conventional meat, also called grain-fed, is meat from animals that are grass-fed for part of their lives and then given a grain-based diet for the remainder. Most red meat available in major supermarkets is grain-fed.</p>
<p>Grass-fed meat comes from animals that have grazed on pasture for their entire lives. This means grass-fed meat tends to have higher levels of unsaturated fats than conventional meat, and is why some <a href="https://www.mdpi.com/2304-8158/11/5/646">research</a> suggests it’s healthier. Grass-fed meat is also likely to cost more.</p>
<p>Organic meat is seen as a premium product as it has to meet <a href="https://www.agriculture.gov.au/biosecurity-trade/export/controlled-goods/organic-bio-dynamic/national-standard">government standards</a> for organic produce. For example, meat labelled as organic cannot use synthetic pesticides or use hormones or antibiotics to stimulate growth. </p>
<p>Processed meats have been preserved by smoking, curing or salting, or by adding chemical preservatives. Examples include sausages, ham, bacon and hot dogs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/538683/original/file-20230721-17-8jb0lp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Sausages and salamis" src="https://images.theconversation.com/files/538683/original/file-20230721-17-8jb0lp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/538683/original/file-20230721-17-8jb0lp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/538683/original/file-20230721-17-8jb0lp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/538683/original/file-20230721-17-8jb0lp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/538683/original/file-20230721-17-8jb0lp.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/538683/original/file-20230721-17-8jb0lp.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/538683/original/file-20230721-17-8jb0lp.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Salami and other smallgoods are processed meats.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<h2>What is the nutritional value of red meat?</h2>
<p><a href="https://www.eatforhealth.gov.au/food-essentials/five-food-groups/lean-meat-and-poultry-fish-eggs-tofu-nuts-and-seeds-and">Red meat</a> contains many nutrients that are important for health, including protein, vitamin B12, iron and zinc. Red meat is a good source of iron and zinc as they are more easily absorbed by the body from meat than from plant foods. </p>
<p>Red meat is often high in saturated fats, but this can <a href="https://www.foodstandards.gov.au/science/monitoringnutrients/ausnut/ausnutdatafiles/Pages/foodnutrient.aspx">range widely</a> from less than 1% to over 25% depending on the cut and whether it’s trimmed of fat or not. Minced meat typically ranges from 2% to 9% saturated fat depending on whether its extra lean or regular.</p>
<p>To limit intake of saturated fats, opt for leaner mince and leaner cuts of meat, such as pork tenderloins or beef steak with the fat trimmed off.</p>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5243954/">Wagyu beef</a> (which simply translates to Wa = Japanese and Gyu = cow) has been touted as a healthier alternative to conventional red meat, as it tends to be higher in unsaturated fats. But research is limited, and ultimately it still contains saturated fat. </p>
<p>Processed meats, such as bacon, salami and sausages, contain beneficial nutrients, but they are also high in saturated fat, sodium and contain preservatives.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/heres-a-meaty-question-are-barbecues-bad-for-your-health-10685">Here's a meaty question – are barbecues bad for your health? </a>
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</em>
</p>
<hr>
<h2>Is red meat bad for your health? And does the type matter?</h2>
<p>It’s widely reported eating too much red meat is bad for your health, because it can increase your risk of heart disease, type 2 diabetes and some cancers. </p>
<p>But most of the evidence for this comes from observational studies, which cannot determine whether red meat intake actually causes the condition. </p>
<p>Most evidence is observational because it’s simply not ethical or feasible to ask someone to eat large amounts of meat every day for many years to see if they develop cancer.</p>
<p>So let’s take a look at the evidence:</p>
<p><strong>Heart disease and type 2 diabetes</strong></p>
<p>In a <a href="https://www.nature.com/articles/s41591-022-01968-z">review</a> of 37 observational studies, the authors found weak evidence of an association between eating unprocessed red meat and heart disease and type 2 diabetes. </p>
<p>But for processed meat, a recent <a href="https://academic.oup.com/eurheartj/article/44/28/2626/7188739">review</a> showed that for each additional 50g of processed meat consumed per day, the risk of heart disease increased by 26% and the risk of type 2 diabetes increased by 44%, on average.</p>
<p><strong>Cancer</strong></p>
<p>Leading international organisations have declared there’s strong evidence consumption of red and processed meat <a href="https://www.wcrf.org/diet-activity-and-cancer/cancer-prevention-recommendations/limit-red-and-processed-meat/">increases the risk of colorectal cancer</a>. </p>
<p>For example, in a <a href="https://academic.oup.com/ije/article/49/1/246/5470096?">study</a> of nearly 500,000 people, each additional 50g of red meat consumed per day increased the risk of colorectal cancer by 18%. And each additional 25g of processed meat consumed per day, equivalent to a slice of ham, increased the risk by 19%.</p>
<p>While <a href="https://pubmed.ncbi.nlm.nih.gov/34455534/">research</a> has linked consumption of red and processed meat with increased risk of other types of cancer, such as lung, pancreatic and breast, the evidence is not consistent.</p>
<p>It also matters how red meat is cooked. For example, cooking a steak over a high heat, especially an open flame, chars the outside. This causes <a href="https://www.cancer.gov/about-cancer/causes-prevention/risk/diet/cooked-meats-fact-sheet">chemical compounds</a> to form that have been shown to cause cancer in very high doses in animal models, and some studies in humans have found an <a href="https://aacrjournals.org/cebp/article/16/12/2664/260099/Meat-and-Meat-Mutagen-Intake-and-Pancreatic-Cancer">association</a> with increased cancer rates.</p>
<p>When it comes to how the animal was raised or its breed, based on current evidence, it’s unlikely the nutritional differences will have a substantial impact on human health. But research is limited in this area. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/538687/original/file-20230721-21-pcuc0r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Steak" src="https://images.theconversation.com/files/538687/original/file-20230721-21-pcuc0r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/538687/original/file-20230721-21-pcuc0r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/538687/original/file-20230721-21-pcuc0r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/538687/original/file-20230721-21-pcuc0r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/538687/original/file-20230721-21-pcuc0r.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/538687/original/file-20230721-21-pcuc0r.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/538687/original/file-20230721-21-pcuc0r.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Roasting is better than cooking over an open flame.</span>
<span class="attribution"><span class="source">jose ignacio pompe/unsplash</span>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
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<strong>
Read more:
<a href="https://theconversation.com/yes-we-still-need-to-cut-down-on-red-and-processed-meat-124486">Yes, we still need to cut down on red and processed meat</a>
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</em>
</p>
<hr>
<h2>How much red meat should you eat?</h2>
<p>Our national <a href="https://www.eatforhealth.gov.au/sites/default/files/files/the_guidelines/n55a_australian_dietary_guidelines_summary_book.pdf">dietary guidelines</a> recommend the average adult eats a maximum of 455g of cooked lean red meat per week (or less than 65g a day, equivalent to one small lamb chop). This is also what’s recommended by the national <a href="https://www.cancer.org.au/cancer-information/causes-and-prevention/diet-and-exercise/meat-and-cancer-risk">Cancer Council</a>.</p>
<p>For heart health specifically, the national <a href="https://www.heartfoundation.org.au/getmedia/d5b9c4a2-8ccb-4fe9-87a2-d4a34541c272/Nutrition_Position_Statement_-_MEAT.pdf">Heart Foundation</a> recommends eating less than 350g of cooked, unprocessed red meat per week (or less than 50g a day).</p>
<p>Many dietary guidelines around the world now also recommend limiting red meat consumption for environmental reasons. To optimise both human nutrition and planetary health, the <a href="https://eatforum.org/lancet-commission/eatinghealthyandsustainable/">EAT-Lancet commission</a> recommends consuming no more than 98g a week of red meat and very low intakes of processed meat.</p>
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<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/should-we-eat-red-meat-the-nutrition-and-the-ethics-47934">Should we eat red meat? The nutrition and the ethics</a>
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</em>
</p>
<hr>
<h2>So what does all of this mean for your diet?</h2>
<p>The bottom line is that red meat can still be enjoyed as part of a <a href="https://www.eatforhealth.gov.au/food-essentials/five-food-groups/lean-meat-and-poultry-fish-eggs-tofu-nuts-and-seeds-and">healthy diet</a>, if not eaten in excess. Where possible, opt for unprocessed or lean cuts, and try to grill less and roast more. Consider swapping red meat for lean chicken or fish occasionally too.</p>
<p>If you are looking for alternatives to meat that are better for your health and the environment, minimally processed plant-based alternatives, such as tofu, beans and lentils, are great options.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/how-to-get-the-nutrients-you-need-without-eating-as-much-red-meat-110274">How to get the nutrients you need without eating as much red meat</a>
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</em>
</p>
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<img src="https://counter.theconversation.com/content/207927/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Katherine Livingstone receives funding from a National Health and Medical Research Council Investigator Grant (APP1173803) and a National Heart Foundation of Australia Vanguard Grant (ID106800).</span></em></p>Most of us are vaguely aware we shouldn’t eat too much red meat, but why? And does the type of meat make a difference?Katherine Livingstone, NHMRC Emerging Leadership Fellow and Senior Research Fellow at the Institute for Physical Activity and Nutrition, Deakin UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/2006892023-06-05T12:09:06Z2023-06-05T12:09:06ZArsenic contamination of food and water is a global public health concern – researchers are studying how it causes cancer<figure><img src="https://images.theconversation.com/files/529435/original/file-20230531-23-iq2312.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C937%2C768&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">One symptom of arsenic poisoning is the growth of plaques on the skin called arsenical keratosis.</span> <span class="attribution"><a class="source" href="https://flic.kr/p/tQzvii">Anita Ghosh/REACH via Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span></figcaption></figure><p>Arsenic is a naturally occurring element found in the Earth’s crust. Exposure to arsenic, often through contaminated food and water, is associated with various negative health effects, <a href="https://www.ncbi.nlm.nih.gov/books/NBK304375/">including cancer</a>. </p>
<p>Arsenic exposure is a global public health issue. A 2020 study estimated that <a href="https://doi.org/10.1126/science.aba1510">up to 200 million people wordwide</a> are exposed to arsenic-contaminated drinking water at levels above the legal limit of <a href="https://www.atsdr.cdc.gov/csem/arsenic/standards.html">10 parts per billion</a> set by the U.S. Environmental Protection Agency and World Health Organization. <a href="https://publications.iarc.fr/Book-And-Report-Series/Iarc-Monographs-On-The-Identification-Of-Carcinogenic-Hazards-To-Humans/Some-Drinking-Water-Disinfectants-And-Contaminants-Including-Arsenic-2004">More than 70 countries</a> are affected, including the United States, Spain, Mexico, Japan, India, China, Canada, Chile, Bangladesh, Bolivia and Argentina.</p>
<p>Since many countries are still affected by high levels of arsenic, we believe arsenic exposure is a global public health issue that requires urgent action. <a href="https://stempel.fiu.edu/research/labs/cancer-research/">We study</a> how <a href="https://www.researchgate.net/profile/Cristina-Andrade-Feraud">exposure to toxic metals</a> like arsenic can <a href="https://scholar.google.com/citations?user=v42J5dMAAAAJ&hl=en">lead to cancer</a> through the formation of <a href="https://theconversation.com/triggering-cancer-cells-to-become-normal-cells-how-stem-cell-therapies-can-provide-new-ways-to-stop-tumors-from-spreading-or-growing-back-191559">cancer stem cells</a>. </p>
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<iframe width="440" height="260" src="https://www.youtube.com/embed/ftvJr-BycJY?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Arsenic water contamination predominantly affects communities of color in the U.S.</span></figcaption>
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<h2>Arsenic contamination of food and water</h2>
<p>Your body can absorb arsenic <a href="https://www.atsdr.cdc.gov/csem/arsenic/what_routes.html">through several routes</a>, such as inhalation and skin contact. However, the most common source of arsenic exposure is through contaminated drinking water or food.</p>
<p>People who live in areas with <a href="https://www.who.int/news-room/fact-sheets/detail/arsenic">naturally high levels of arsenic in the soil and water</a> are at particular risk. In the U.S., for example, that includes regions in the Southwest such as Arizona, Nevada and New Mexico. Additionally, <a href="https://www.wolterskluwer.com/en/solutions/ovid/environmental-and-occupational-medicine-3485">human activities</a> such as mining and agriculture can also increase arsenic in food and water sources.</p>
<p>High levels of arsenic can also be found in <a href="https://theconversation.com/should-we-worry-about-arsenic-in-baby-cereal-and-drinking-water-57948">food and drink products</a>, <a href="https://doi.org/10.1016/j.fct.2018.01.018">particularly rice</a> and rice-based products like rice cereals and crackers. A 2019 Consumer Reports investigation even found that <a href="https://www.consumerreports.org/water-quality/arsenic-in-some-bottled-water-brands-at-unsafe-levels-a1198655241/">some brands of bottled water</a> sold in the U.S. contained levels of arsenic that exceeded the legal limit. Alarmingly, multiple studies have also found that several <a href="https://www.consumerreports.org/food-safety/most-baby-foods-contain-arsenic-lead-and-other-heavy-metals/">popular baby food brands</a> contained arsenic at concentrations much higher than the legal limit.</p>
<h2>Arsenic and cancer stem cells</h2>
<p>Chronic exposure to arsenic increases the <a href="https://doi.org/10.1093/jnci/djx201">risk</a> <a href="https://doi.org/10.1016/j.scitotenv.2019.136071">of</a> <a href="https://doi.org/10.1016/j.scitotenv.2019.134128">developing</a> <a href="https://doi.org/10.1158/1055-9965.epi-13-0234-t">multiple</a> <a href="https://doi.org/10.1016/j.scitotenv.2015.08.070">types</a> <a href="https://doi.org/10.1016/s0041-008x(02)00022-4">of cancer</a>.</p>
<p>The mechanisms by which arsenic causes cancer are complex and not yet fully understood. However, research suggests that <a href="https://doi.org/10.3109%2F10408444.2010.506641">arsenic can</a> <a href="https://doi.org/10.1021%2Facs.chemrestox.9b00464">damage DNA</a>, <a href="https://doi.org/10.1007/s00204-013-1131-4">disrupt cell</a> <a href="https://doi.org/10.1093/toxsci/kfy247">signaling pathways</a> and <a href="https://doi.org/10.1186/1476-069X-12-73">impair the</a> <a href="https://doi.org/10.1016/j.cotox.2018.01.003">immune system</a>, all of which can contribute to cancer development.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Microscopy images of ovarian epithelial cells before and after chronic arsenic exposure" src="https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=235&fit=crop&dpr=1 600w, https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=235&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=235&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=295&fit=crop&dpr=1 754w, https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=295&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/529436/original/file-20230531-17-e8zn68.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=295&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The image on the left shows ovarian epithelial cells under normal conditions. The image on the right shows the cells after three weeks of chronic arsenic exposure at 75 parts per billion.</span>
<span class="attribution"><span class="source">Cristina M. Andrade-Feraud/Azzam Laboratory at FIU</span>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>Scientists <a href="https://doi.org/10.1289%2Fehp.1204987">have also linked</a> <a href="https://doi.org/10.1289%2Fehp.0901059">chronic arsenic exposure</a> to the development of <a href="https://theconversation.com/triggering-cancer-cells-to-become-normal-cells-how-stem-cell-therapies-can-provide-new-ways-to-stop-tumors-from-spreading-or-growing-back-191559">cancer stem cells</a>. These are cells within tumors thought to be responsible for cancer growth and spread. Like normal stem cells in the body, cancer stem cells can develop into many different types of cells. At what stage of cellular development a stem cell acquires the genetic mutation that turns it into a cancer stem cell remains unknown.</p>
<p><a href="https://stempel.fiu.edu/research/labs/cancer-research/">Our research</a> aims to identify what type of cell arsenic targets to form a cancer stem cell. We are currently using cell cultures obtained from the same organ at different stages of cellular development to examine how the origins of cells affect the formation of cancer stem cells.</p>
<p>Preventing chronic arsenic exposure is critical to reducing the burden of arsenic-related health effects. Further research is needed to understand arsenic-induced cancer stem cell formation and develop effective strategies to prevent it. In the meantime, continued monitoring and regulation of this toxic metal in food and water sources could help improve the health of affected communities.</p><img src="https://counter.theconversation.com/content/200689/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Diana Azzam receives funding from the Florida Department of Health and the National Institute of Health.</span></em></p><p class="fine-print"><em><span>Cristina Andrade-Feraud does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Millions of people worldwide are exposed via soil and water to arsenic, whether naturally occurring or related to pollution. Chronic exposure is linked to the formation of cancer stem cells.Cristina Andrade-Feraud, Ph.D. Candidate in Environmental Health Sciences, Florida International UniversityDiana Azzam, Assistant Professor of Environmental Health Sciences, Florida International UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1934312023-01-30T13:12:57Z2023-01-30T13:12:57ZDoes this cause cancer? How scientists determine whether a chemical is carcinogenic – sometimes with controversial results<figure><img src="https://images.theconversation.com/files/506177/original/file-20230124-18-m5hdd.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C3000%2C1500&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Carcinogenic chemicals are labeled with a health hazard warning symbol. </span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/illustration/serious-health-hazard-royalty-free-illustration/1353836395">Peter Etchells/iStock via Getty Images Plus</a></span></figcaption></figure><p>People are <a href="https://www.universityofcalifornia.edu/news/toxic-exposure-chemicals-are-our-water-food-air-and-furniture">exposed to numerous chemicals</a> throughout their lifetimes. These chemicals can be from the air, foods, personal care items, household products and medications. Unfortunately, exposure to certain chemicals can cause harmful health effects, including cancer. Substances that cause cancer are called <a href="https://www.genome.gov/genetics-glossary/Carcinogen">carcinogens</a>. Familiar examples include <a href="https://monographs.iarc.who.int/wp-content/uploads/2018/06/mono100E-6.pdf">tobacco smoke</a>, <a href="https://monographs.iarc.who.int/wp-content/uploads/2018/06/mono100D-9.pdf">radon</a>, <a href="https://monographs.iarc.who.int/wp-content/uploads/2018/06/mono100C-11.pdf">asbestos</a> and <a href="https://www.iarc.who.int/news-events/iarc-diesel-engine-exhaust-carcinogenic/">diesel engine exhaust</a>.</p>
<p>To protect the health of the public, national and international health agencies evaluate many new and existing chemicals to determine if they are likely to be carcinogens in a process called <a href="https://pubmed.ncbi.nlm.nih.gov/9715519/">cancer hazard identification</a>. If agencies judge the chemicals to be carcinogenic, they conduct further assessments to determine the level of risk, and legislators may put regulations in place to limit, or completely halt, the production and use of these chemicals.</p>
<p><a href="https://www.engr.colostate.edu/cbe/people/brad-reisfeld/">I am a scientist</a> who studies how the human body processes foreign chemicals, like environmental pollutants and drugs, and the effects of these chemicals on health. As part of my work, I have participated in chemical and cancer hazard identifications for several agencies, including the World Health Organization’s <a href="https://www.iarc.who.int">International Agency for Research on Cancer</a>. Here’s how chemicals can cause cancer, and how we classify chemicals based on on how carcinogenic they are – sometimes with controversial results.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Person in protective suit spraying herbicide on plants" src="https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/506173/original/file-20230124-306-u6qsnd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Glyphosate, an herbicide used in products like Roundup, was classified by the IARC as probably carcinogenic to humans in 2015.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/person-in-protective-suit-spraying-herbicide-on-royalty-free-image/1327771135">Adriana Duduleanu/EyeEm via Getty Images</a></span>
</figcaption>
</figure>
<h2>How do chemicals cause cancer?</h2>
<p>The mechanisms behind how toxic chemicals can lead to cancer <a href="https://www.ncbi.nlm.nih.gov/books/NBK570326/">are complex</a>. </p>
<p>After a person is exposed to a carcinogen, the chemical is generally absorbed into the body and distributed into different tissues. Once the chemical has moved into the cells, it often undergoes chemical reactions that convert it into other forms. </p>
<p>The products of these reactions can directly or indirectly affect the cell’s genes. Altering genes, which contain the cell’s instructions on how to produce specific molecules, or the processes that regulate them can ultimately result in dysfunctional cells if the genetic damage isn’t repaired. These cells don’t respond normally to cellular signals and can grow and divide at abnormal rates, which are characteristic features of cancer cells.</p>
<h2>How are chemicals classified for carcinogenicity?</h2>
<p>To help safeguard the public and reduce the incidence of cancer, several agencies have developed procedures to classify and categorize chemicals based on their potential to be carcinogenic. </p>
<p><a href="https://www.atsdr.cdc.gov/pha-guidance/conducting_scientific_evaluations/indepth_toxicological_analysis/EvaluateEvidenceCancerEffects.html">Among them</a> are the International Agency for Research on Cancer, or IARC Monographs; the National Toxicology Program, or NTP; and the U.S. Environmental Protection Agency, or EPA. In general, these agencies examine a critical question: How strong is the evidence that a substance causes cancer or biological changes that could be related to cancer in people? Understanding the procedures used to answer this question can help with interpreting the decisions these agencies make.</p>
<p>The <a href="https://monographs.iarc.who.int/iarc-monographs-preamble-preamble-to-the-iarc-monographs/">procedures used by the IARC</a> – because of its long history, credibility and strong international reputation – provide a good example of how this process works. It’s designed to be transparent and minimize bias, spanning over a year from selecting a chemical for evaluation to its final classification. </p>
<p>In this process, the IARC selects and invites a panel of scientific experts on the chemical to be evaluated. The panel does not conduct new research on its own, but carefully reviews all available papers in the scientific literature on the chemical’s carcinogenicity in cell and bacterial cultures, animals and people. To assess the strength of the evidence, the panel carefully considers the number of studies that are available and the consistency of the results, as well as the scientific quality and relevance of each study to cancer in people.</p>
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<figcaption><span class="caption">Chemicals can be carcinogenic to varying degrees.</span></figcaption>
</figure>
<p>After discussing and deliberating on the results, the panel makes a final consensus classification. This classification places the chemical into one of four groups: Group 1 indicates that the chemical is carcinogenic to people, Group 2A that it is probably carcinogenic to people, Group 2B that it is possibly carcinogenic to people, and Group 3 that it is not classifiable. A Group 3 classification does not indicate that the compound is not carcinogenic, but rather that the panel could not draw a conclusion about whether there is a causal link between the chemical and cancer from available studies. For example, exposure to several chemicals can make it unclear which ones are responsible for a later cancer diagnosis.</p>
<p>During its 50-year history, the IARC has evaluated and classified <a href="https://monographs.iarc.who.int/wp-content/uploads/2018/07/cumulative-cross-index.pdf">over 1,000 chemicals and other hazards</a>. Many of these classifications have had broad societal implications, such as those for tobacco smoke, ambient air pollution, diesel engine exhaust and processed meat. All were classified as Group 1, or confirmed to be carcinogenic to humans. <a href="https://www.iarc.who.int/pressrelease/iarc-classifies-radiofrequency-electromagnetic-fields-as-possibly-carcinogenic-to-humans/">Electromagnetic radiation</a> emitted by mobile phones was classified as Group 2B, or possibly carcinogenic, and <a href="https://www.iarc.who.int/featured-news/media-centre-iarc-news-redmeat/">red meat</a> was classified as Group 2A, or probably carcinogenic. Though they haven’t directly led to any regulations, these classifications have motivated <a href="https://doi.org/10.3389/fpubh.2019.00223">additional</a> <a href="https://doi.org/10.1007/s13668-021-00377-x">scientific studies</a>. While the IARC can advise regulators, it’s up to countries to implement policies.</p>
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<p>It is important to note that classifications do not indicate the size of the risk but are important in supporting health agencies worldwide as they implement actions to limit exposures to known, probable and possible carcinogens. In 2020, when the IARC <a href="https://www.iarc.who.int/news-events/iarc-monographs-evaluation-of-the-carcinogenicity-of-opium-consumption/">classified opium consumption as Group 1</a>, or carcinogenic to humans, this led the government of Iran to <a href="https://www.youtube.com/watch?v=hJDlJhtPeiQ">implement policies</a> to reduce opium addiction in the country.</p>
<h2>Controversies in carcinogenicity classifications</h2>
<p>Though classifications from the IARC are based on robust scientific evidence, some have <a href="https://doi.org/10.1093/carcin/bgv062">proved to be controversial</a>. </p>
<p>For instance, in 2015, the IARC evaluated the carcinogenicity of <a href="https://publications.iarc.fr/Book-And-Report-Series/Iarc-Monographs-On-The-Identification-Of-Carcinogenic-Hazards-To-Humans/Some-Organophosphate-Insecticides-And-Herbicides-2017">glyphosate</a>, a widely used weedkiller found in products like Roundup, which is produced by Monsanto. A panel of 17 experts from 11 countries systematically reviewed results from over 1,000 scientific studies and classified glyphosate as “probably carcinogenic to humans,” or Group 2A.</p>
<p>Owing to its widespread usage and <a href="https://www.transparencymarketresearch.com/glyphosate-market.html">multibillion-dollar market value</a>, a cancer classification decision for glyphosate has significant potential financial and legal consequences. Following its evaluation, the IARC received support from many <a href="https://oehha.ca.gov/proposition-65/general-info/oehha-statement-regarding-us-epas-press-release-and-registrant-letter">regulatory</a> and <a href="https://www.env-health.org/campaigns/glyphosate-why-the-eu-needs-to-protect-health-ban-the-popular-weedkiller/">scientific bodies</a> but was <a href="https://www.science.org/content/article/who-rebuts-house-committee-criticisms-about-glyphosate-cancer-warning">criticized by others</a>. Other agencies, <a href="https://www.gao.gov/products/gao-19-280">including</a> <a href="https://www.epa.gov/office-inspector-general/report-epa-needs-improve-transparency-its-cancer-assessment-process">the EPA</a>, have seen similar controversies and politicization of their hazard identifications and regulatory decisions.</p>
<p>I believe that agencies like the IARC play a critical role in evaluating the health effects of certain chemicals and in reducing exposure to potential carcinogens. Helping people better understand how these agencies evaluate chemicals can go a long way to ensure transparency and help protect environmental and public health.</p><img src="https://counter.theconversation.com/content/193431/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Brad Reisfeld does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The WHO’s International Agency for Research on Cancer convenes a panel of scientific experts to review available evidence on whether specific chemicals or occupational exposures may cause cancer.Brad Reisfeld, Professor of Chemical and Biological Engineering, Colorado State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1921542023-01-05T16:19:06Z2023-01-05T16:19:06ZFoams used in car seats and mattresses are hard to recycle – we made a plant-based version that avoids polyurethane’s health risks, too<figure><img src="https://images.theconversation.com/files/501976/original/file-20221219-16-5a8mrd.jpg?ixlib=rb-1.1.0&rect=6%2C92%2C4091%2C2881&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">You may be sitting on polyurethane foam right now.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/golden-sponge-foam-texture-royalty-free-image/134942499">Akhmad Bayuri/iStock/Getty Images Plus</a></span></figcaption></figure><p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take about interesting academic work.</em></p>
<h2>The big idea</h2>
<p>A new plant-based substitute for polyurethane foam eliminates the health risk of the material, commonly found in insulation, car seats and other types of cushioning, and it’s more environmentally sustainable, <a href="https://www.nature.com/articles/s41893-022-01022-3">our new research shows</a>.</p>
<p>Polyurethane foams are all around you, anywhere a lightweight material is needed for cushioning or structural support. But they’re typically made using chemicals that are <a href="https://www.osha.gov/isocyanates">suspected carcinogens</a>.</p>
<p>Polyurethanes are typically produced in a very fast reaction between two chemicals made by the petrochemical industry: polyols and isocyanates. While much work has gone into finding replacements for the polyol component of polyurethane foams, the isocyanate component has largely remained, despite its <a href="https://www.osha.gov/isocyanates">consequences for human health</a>. <a href="https://doi.org/10.1039/D0GC01659D">Bio-based foams</a> can avoid that component.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/488841/original/file-20221008-59028-9iaitu.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Four chunks of bio-based foam, looking a lot like brownies on a tray." src="https://images.theconversation.com/files/488841/original/file-20221008-59028-9iaitu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/488841/original/file-20221008-59028-9iaitu.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=184&fit=crop&dpr=1 600w, https://images.theconversation.com/files/488841/original/file-20221008-59028-9iaitu.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=184&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/488841/original/file-20221008-59028-9iaitu.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=184&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/488841/original/file-20221008-59028-9iaitu.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=232&fit=crop&dpr=1 754w, https://images.theconversation.com/files/488841/original/file-20221008-59028-9iaitu.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=232&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/488841/original/file-20221008-59028-9iaitu.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=232&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">These bio-based foams avoid the need for petroleum products.</span>
<span class="attribution"><span class="source">Srikanth Pilla</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>We created a <a href="https://www.nature.com/articles/s41893-022-01022-3">durable bio-based foam</a> using lignin, a byproduct of the paper pulping industry, and a vegetable oil-based curing agent that introduces flexibility and toughness to the final material.</p>
<p>At the heart of the innovation is the ability to create a system that “gels,” both in the sense that the materials are compatible with one another and that they physically create a gel quickly so that the addition of a foaming agent can create the lightweight structure associated with polyurethane foams.</p>
<p>Lignin is a <a href="https://doi.org/10.1039/D1GC02744A">difficult material to convert into a usable chemical</a>, given its complicated and heterogeneous structure. We used this structure to create a network of bonds that enabled what we believe is the world’s first lignin-based nonisocyanate foam.</p>
<p>The foam can also be <a href="https://doi.org/10.1039/C7GC01496A">recycled</a> because it has bonds that can <a href="https://doi.org/10.1038/s41557-020-00614-w">unzip</a> the chemical network after it has formed. The main components used to produce the foam can then be extracted and used again.</p>
<h2>Why it matters</h2>
<p>Polyurethane foams are the world’s sixth-most-produced plastic yet among the least <a href="https://www.americanchemistry.com/industry-groups/center-for-the-polyurethanes-industry-cpi/applications-benefits/sustainability">recycled materials</a>. They are also designed for durability, meaning they will remain in the environment for several generations. </p>
<p>They contribute to the plastic waste problem for the world’s oceans, land and air, and to <a href="https://doi.org/10.1016/j.jhazmat.2021.127861">human health problems</a>. Today, plastics can be found in <a href="https://doi.org/10.1016/j.ancene.2016.01.002">virtually every creature in the terrestrial ecosystem</a>. And since most plastics are made from petroleum products, they’re connected to fossil fuel extraction, which contributes to climate change.</p>
<p>The fully bio-based origin of our foams addresses the issue of carbon neutrality, and the chemical recycling capability ensures that waste plastic has a value attached to it so it is less likely to be thrown away. Ensuring <a href="https://doi.org/10.1002/macp.202100488">waste has value</a> is a hallmark of the circular approach to manufacturing – attaching a monetary value to things tends to decrease the amount that is discarded.</p>
<figure class="align-center ">
<img alt="Illustration shows the recycling process including unzipping the molecules." src="https://images.theconversation.com/files/490558/original/file-20221019-19-a7wqv6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490558/original/file-20221019-19-a7wqv6.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=537&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490558/original/file-20221019-19-a7wqv6.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=537&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490558/original/file-20221019-19-a7wqv6.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=537&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490558/original/file-20221019-19-a7wqv6.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=675&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490558/original/file-20221019-19-a7wqv6.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=675&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490558/original/file-20221019-19-a7wqv6.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=675&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">How the chemicals in bio-based foams can be recycled and reused.</span>
<span class="attribution"><span class="source">Srikanth Pilla</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>We hope the nature of these foams inspires others to design plastics with the full life cycle in mind. Just as plastics need to be designed according to properties of their initial application, they also need to be designed to avoid the final destination of 90% of plastic waste: landfills and the environment.</p>
<h2>What’s next</h2>
<p>Our initial versions of bio-based foams produce a rigid material suitable for use in foam-core boards used in construction or for insulation in refrigerators. We have also created a lightweight and flexible version that can be used for cushioning and packaging applications. Initial testing of these materials showed good durability in wet conditions, increasing their chance of gaining commercial adoption. </p>
<figure class="align-center ">
<img alt="Two men and two women stand over a beaker with dark liquid in it" src="https://images.theconversation.com/files/490561/original/file-20221019-20-p2m2rj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/490561/original/file-20221019-20-p2m2rj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/490561/original/file-20221019-20-p2m2rj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/490561/original/file-20221019-20-p2m2rj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/490561/original/file-20221019-20-p2m2rj.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/490561/original/file-20221019-20-p2m2rj.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/490561/original/file-20221019-20-p2m2rj.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The authors with two students show methods for recycling bio-based foam.</span>
<span class="attribution"><a class="source" href="https://news.clemson.edu/green-foam-eliminates-the-need-for-toxic-chemicals/">Clemson University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Polyurethane foams are used so extensively because of their <a href="https://doi.org/10.3390/ma11101841">versatility</a>. The formulation that we initially discovered is being translated to create a library of precursors that can be mixed to produce the desired properties, like strength and washability, in each application.</p><img src="https://counter.theconversation.com/content/192154/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Srikanth Pilla receives funding from the National Science Foundation (award # 2122822) and Department of Energy (award # DE-SC0021367) to support this work.</span></em></p><p class="fine-print"><em><span>James Sternberg receives funding from the National Science Foundation (award # 2122822) and Department of Energy (award # DE-SC0021367) to support this work. </span></em></p>Polyurethane foams are the world’s sixth-most-produced plastic yet among the least recycled materials.Srikanth Pilla, Professor of Engineering, Clemson UniversityJames Sternberg, Research Assistant Professor of Automotive Engineering, Clemson UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1916512022-10-17T17:38:56Z2022-10-17T17:38:56ZSnow can spread and worsen the effects of pollutants in the environment<figure><img src="https://images.theconversation.com/files/488312/original/file-20221005-25-3ul0kh.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C5068%2C3368&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Snow's physical properties mean that it can accumulate chemicals from the environment, including nanoparticles from car exhaust.</span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><iframe style="width: 100%; height: 100px; border: none; position: relative; z-index: 1;" allowtransparency="" allow="clipboard-read; clipboard-write" src="https://narrations.ad-auris.com/widget/the-conversation-canada/snow-can-spread-and-worsen-the-effects-of-pollutants-in-the-environment" width="100%" height="400"></iframe>
<p>By October, autumn’s arrival brings with it the promise of winter — and snow. </p>
<p>And with it comes a quieter world, thanks to snow’s ability to absorb noise. This is because the spaces between snow crystals limit sound waves from bouncing around, creating a soundproofing effect. </p>
<p>Snow also adsorbs other matters it comes into contact with. Adsorption is when substances adhere on surfaces of materials (usually liquids or solids). The adsorptive properties of snow are the reason for some of its unique features, including its loosely bound crystalline porous structure with finely divided individually shaped flakes with large surface areas. </p>
<p>Its dynamic changes between ice and liquid states facilitate the absorption and release of pollutants, depending on prevailing surface and atmospheric conditions. </p>
<p>As an analytical material chemist with a research background in adsorption, I am interested in understanding how various materials — like snow — adsorb certain substances, like persistent organic and vehicular exhaust pollutants.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/489891/original/file-20221016-22-qbrsr0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="a pile of dirty snow at a street corner" src="https://images.theconversation.com/files/489891/original/file-20221016-22-qbrsr0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/489891/original/file-20221016-22-qbrsr0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/489891/original/file-20221016-22-qbrsr0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/489891/original/file-20221016-22-qbrsr0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/489891/original/file-20221016-22-qbrsr0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/489891/original/file-20221016-22-qbrsr0.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/489891/original/file-20221016-22-qbrsr0.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">During winter, piles of snow like this one become a regular sight.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Snow and pollution</h2>
<p>In the winter, snow becomes a superabsorbent for a wide range of <a href="https://doi.org/10.1016/j.scitotenv.2020.144136">pollutants</a>, including vehicular exhaust particulate matters, <a href="https://doi.org/10.1016/j.microc.2014.10.010">persistent organic pollutants</a> (POPs), trace metals and <a href="https://doi.org/10.1016/j.watres.2021.117493">chlorides from road salts</a>. </p>
<p>As snow subsequently moves around or melts, most of these pollutants find their way into underground pipes and aquifers. </p>
<p>POPs are some of the most dangerous pollutants because they remain active, lasting for several years within their environments before <a href="https://doi.org/10.1016/j.rsma.2022.102688">finally degrading into other chemical forms</a>. POPs, such as polychlorinated biphenyls, organochlorine pesticides and perflouroalkylated substances, have <a href="https://www.epa.gov/international-cooperation/persistent-organic-pollutants-global-issue-global-response">severe environmental impacts</a>. </p>
<p>They are classified under the <a href="https://www.canada.ca/en/environment-climate-change/services/canadian-environmental-protection-act-registry/historical/plans-policies/statement-pops-negotiations/backgrounder-persistent-organic-pollutants.html">Toxic Substances Management Policy as Track 1 substances in Canada, and are usually targeted for environmental removal</a>. </p>
<p>Just like POPs, very little is also known about how chemical pollutants from the exhausts of gasoline-powered vehicles interact with snow. </p>
<p>In Canadian cities, snow is moved around through various means, including snow melts, during plowing, on tires of vehicles or even soles of pedestrian shoes. During transportation, changes in ground surface pressure and ambient temperature can also affect the adsorption rates of chemical pollutants on snow. </p>
<p>Research conducted in Québec has shown that snow adsorbs significant amounts of organic pollutants and aerosol particles from exhaust pipes <a href="https://doi.org/10.1016/j.envpol.2017.01.082">within 30 minutes of exposure</a>. These researchers also observed the adsorption of aerosol particles with larger particulate sizes (approximately 50-400 nm) relative to smaller nanoparticles (less than 50 nm).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/489886/original/file-20221016-56148-cmyp4e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="cars follow behind three snowplows on a highway" src="https://images.theconversation.com/files/489886/original/file-20221016-56148-cmyp4e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/489886/original/file-20221016-56148-cmyp4e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/489886/original/file-20221016-56148-cmyp4e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/489886/original/file-20221016-56148-cmyp4e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/489886/original/file-20221016-56148-cmyp4e.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/489886/original/file-20221016-56148-cmyp4e.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/489886/original/file-20221016-56148-cmyp4e.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Snow carrying pollutants from road salts and vehicle exhausts can make its way into water systems.</span>
<span class="attribution"><span class="source">(Shutterstock)</span></span>
</figcaption>
</figure>
<h2>Health effects</h2>
<p>POPs are introduced into the environment through agricultural and industrial practices. Most of them may have come from other anthropogenic sources but are unintentionally released from simple events like <a href="https://nepis.epa.gov/Exe/ZyPDF.cgi/70000AZL.PDF?Dockey=70000AZL.PDF">burning household waste</a>. </p>
<p>Burning industrial, municipal or medical wastes can also release dioxins and furans. <a href="https://www.atsdr.cdc.gov/ToxProfiles/tp94-c6.pdf">Toxaphene</a> and <a href="https://www.atsdr.cdc.gov/ToxProfiles/tp90-c6.pdf">hexachlorobenzene</a> could originate from uncontrolled insecticide and pesticide waste disposal. Upon exposure during winter, these chemical pollutants find their way into the snow, then into surface water and up the food chain. They can adversely affect aquatic life when subsequently introduced into the aquatic ecosystems. </p>
<p>POPs and exhaust particulate matters can <a href="https://www.epa.gov/international-cooperation/persistent-organic-pollutants-global-issue-global-response">affect human health</a>. They can cause allergies, hypersensitivity, birth defects and neurological disorders. Most POPs are carcinogens. Some of them may alter the nervous systems, leading to chronic health conditions. POPs can also affect reproductive health and disrupt the immune system. Some particulate matters cause lung inflammation and increase the risk of blood clotting. </p>
<p>These severe impacts on human health and environment sustainability are why POPs are <a href="https://www.canada.ca/en/environment-climate-change/corporate/international-affairs/partnerships-organizations/persistent-organic-pollutants-stockholm-convention.html">currently regulated under the Stockholm Convention, as adopted by Canada in 2001</a>. </p>
<p>Between applicable industries and environmental monitoring agencies, federal and provincial governments and us, everyone has a part to play. All hands must be on deck in providing sustainable regulations for these pollutants. And as we approach winter, measures should be developed to reduce the amount of pollutants that can accumulate and persist in snow.</p><img src="https://counter.theconversation.com/content/191651/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eduok, U. does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>From persistent chemicals to exhaust particulate matter, snow accumulates highly toxic pollutants. Regulations are needed to address the impacts on water supplies and the food chain.Eduok, U., Senior Research Associate, Chemistry, Western UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1635632021-07-13T12:29:34Z2021-07-13T12:29:34Z25-year-long study of Black women links frequent use of lye-based hair relaxers to a higher risk of breast cancer<figure><img src="https://images.theconversation.com/files/410016/original/file-20210706-19-1kr29ru.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C8634%2C5756&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Research suggests Black women may want to be cautious about heavy use of lye-based chemical hair relaxers.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/this-product-sounds-great-royalty-free-image/1270972336?adppopup=true">ljubaphoto/E+ via Getty Images</a></span></figcaption></figure><p><em>The <a href="https://theconversation.com/us/topics/research-brief-83231">Research Brief</a> is a short take about interesting academic work.</em></p>
<h2>The big idea</h2>
<p>Frequent and long-term use of lye-based hair straightening products, or relaxers, may increase the risk of breast cancer among Black women, compared with more moderate use.</p>
<p>Boston University’s <a href="https://www.bu.edu/bwhs/">Black Women’s Health Study</a> followed 59,000 self-identified African American women for over 25 years, sending questionnaires every two years on new diagnoses and factors that might influence their health. </p>
<p>Using these data in <a href="https://doi.org/10.1093/carcin/bgab041">our own study</a>, <a href="https://www.bumc.bu.edu/busm/profile/kimberly-bertrand/">my team of epidemiologists and I</a> found that Black women who used <a href="https://www.cdc.gov/niosh/topics/sodium-hydroxide/default.html">hair products containing lye</a> at least seven times a year for 15 or more years had an approximately <a href="https://doi.org/10.1093/carcin/bgab041">30% increased risk</a> of <a href="https://www.cancer.org/cancer/breast-cancer/understanding-a-breast-cancer-diagnosis/breast-cancer-hormone-receptor-status.html">estrogen receptor positive</a> breast cancer compared with more infrequent users. </p>
<p>The minimal association between hair relaxers (with or without lye) and breast cancer risk for moderate users is generally reassuring. But the elevated risk for the heaviest users of lye-based hair products – which included about 20% of study participants – is concerning.</p>
<h2>Why it matters</h2>
<p>There is an urgent need to address racial disparities in breast cancer. </p>
<p>Black women diagnosed with breast cancer are <a href="https://doi.org/10.3322/caac.21583">40% more likely to die</a> from the disease than white women. While systemic factors such as <a href="https://doi.org/10.1001/archinte.166.20.2244">delays in diagnosis</a> and <a href="https://doi.org/10.1001/jamaoncol.2019.5672">poorer health care</a> likely contribute to this disparity, they don’t seem to fully explain the survival gap between Black and white women.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/410020/original/file-20210706-13-7cz4s4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Three diverse women practicing yoga outdoors, with a Black woman in the focus" src="https://images.theconversation.com/files/410020/original/file-20210706-13-7cz4s4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/410020/original/file-20210706-13-7cz4s4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/410020/original/file-20210706-13-7cz4s4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/410020/original/file-20210706-13-7cz4s4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/410020/original/file-20210706-13-7cz4s4.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/410020/original/file-20210706-13-7cz4s4.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/410020/original/file-20210706-13-7cz4s4.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Black and white women have the same lifetime risk for breast cancer, but Black women are often diagnosed with more aggressive forms earlier in life.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/photo/women-outdoors-doing-yoga-lotus-pose-with-prayer-royalty-free-image/1311318336?adppopup=true">kali9/E+ via Getty Images</a></span>
</figcaption>
</figure>
<p>Black women are more likely than white women to develop <a href="https://doi.org/10.3322/caac.21583">highly aggressive breast cancers</a> that have higher mortality rates, but researchers don’t really know why. However, scientists do know that <a href="https://doi.org/10.1038/jes.2014.32">chemical hair relaxers</a>, more often used by Black women, contain <a href="https://doi.org/10.1016/j.envres.2018.03.030">potentially harmful</a> <a href="https://www.fda.gov/consumers/consumer-updates/formaldehyde-hair-smoothing-products-what-you-should-know">chemicals</a>, including possible carcinogens and chemicals known as <a href="https://www.niehs.nih.gov/health/topics/agents/endocrine/index.cfm">endocrine disrupters</a>, which can interfere with hormone function and could raise breast cancer risk. In the Black Women’s Health Study, <a href="https://doi.org/10.1093/carcin/bgab041">95% of women</a> reported past or current use of these products.</p>
<p>This study fills a knowledge gap on the potential health effects of a consumer product popular among Black women. Given these findings, women may want to be cautious about the types of personal-care products they choose.</p>
<h2>What still isn’t known</h2>
<p>Because the Black Women’s Health Study did not have information on specific brands of hair relaxers, my team and I could not determine which specific ingredients might be most relevant for breast cancer risk. In addition, because we asked about hair relaxer use before 1997, the results of this study may not apply to products on the market today. </p>
<p>Though our findings suggest a link between the use of certain types of hair relaxers and breast cancer, epidemiologic studies such as this one cannot definitively prove that hair relaxers cause breast cancer. Additional research is needed, especially on currently available products.</p>
<h2>What other research is being done</h2>
<p><a href="https://doi.org/10.1289/EHP5221">Evidence from animal</a> and other <a href="https://doi.org/10.1016/j.envres.2018.03.030">experimental studies</a> support a possible link between chemicals included in hair relaxers and cancer development. <a href="https://doi.org/10.1093/carcin/bgx060">Studies</a> on <a href="https://doi.org/10.1002/ijc.32738">hair relaxer use</a> and <a href="https://doi.org/10.1093/carcin/bgy002">breast cancer risk</a> in people, however, have had inconsistent results, possibly because of differences in the types of products used or asked about.</p>
<h2>What’s next</h2>
<p>Thanks to 59,000 study participants in the Black Women’s Health Study, our research team continues to investigate risk factors for breast cancer and other diseases in Black women. By understanding what causes disease and learning about ways to lower risk, society can move one step closer toward eliminating health disparities.</p>
<p>[<em>Like what you’ve read? Want more?</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=likethis">Sign up for The Conversation’s daily newsletter</a>.]</p><img src="https://counter.theconversation.com/content/163563/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>This work was supported by the National Institutes of Health (U01 CA164974, R01 CA58420).</span></em></p>Researchers had suspected that chemical hair relaxers might be behind racial disparities in breast cancer diagnoses. A new study narrows in on lye as a possible cause for that link.Kimberly Bertrand, Assistant Professor of Medicine, Boston UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1595272021-05-06T18:12:35Z2021-05-06T18:12:35ZWildfires are contaminating drinking water systems, and it’s more widespread than people realize<figure><img src="https://images.theconversation.com/files/399022/original/file-20210505-21-d89nh3.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C2995%2C1994&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fire in one part of a community can contaminate the water system used by other residents, as Santa Rosa, California, discovered after the Tubbs Fire.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/an-aerial-view-of-homes-that-were-destroyed-by-the-tubbs-news-photo/860298200">Justin Sullivan/Getty Images</a></span></figcaption></figure><p>More than <a href="https://www.predictiveservices.nifc.gov/intelligence/2020_statssumm/annual_report_2020.pdf">58,000</a> fires scorched the United States last year, and 2021 is on track to be even <a href="https://droughtmonitor.unl.edu/">drier</a>. What many people don’t realize is that these wildfires can do lasting damage beyond the reach of the flames – they can contaminate entire drinking water systems with carcinogens that last for months after the blaze. That water flows to homes, contaminating the plumbing, too.</p>
<p>Over the past four years, wildfires have contaminated drinking water distribution networks and building plumbing for more than 240,000 people. </p>
<p>Small water systems serving housing developments, mobile home parks, businesses and small towns have been particularly hard-hit. Most didn’t realize their water was unsafe until weeks to months after the fire.</p>
<p>The problem starts when wildfire smoke gets into the system or <a href="https://doi.org/10.1039/D0EW00836B">plastic in water systems heats up</a>. Heating can cause plastics to release harmful chemicals, like benzene, which can contaminate drinking water and permeate the system. </p>
<p>As an <a href="https://engineering.purdue.edu/CE/People/ptProfile?resource_id=110359">environmental engineer</a>, I and my colleagues work with communities recovering from wildfires and other natural disasters. Last year, at least seven water systems were found to be contaminated, suggesting drinking water contamination may be a more widespread problem than people realize. </p>
<p>Our <a href="https://doi.org/10.1007/s11069-021-04714-9">new study</a> identifies critical issues that households and businesses should consider after a wildfire. Failing to address them can harm people’s health – mental, physical and financial.</p>
<h2>Wildfires make drinking water unsafe</h2>
<p>When wildfires <a href="https://doi.org/10.1002/aws2.1183">damage</a> water distribution pipes, wells and the plumbing in homes and other buildings, they can create immediate health risks. A building’s plumbing can become contaminated by smoke getting sucked into water systems, by heat damaging <a href="https://doi.org/10.1039/D0EW00836B">plastic pipes</a> – or contamination penetrating into the plumbing and leaching out slowly over time.</p>
<p>Since 2017, multiple fires have rendered drinking water systems unsafe, including <a href="https://yourwater.oregon.gov/wildfire-pws.php?pwsno=00603">the</a> <a href="https://yourwater.oregon.gov/wildfire-pws.php?pwsno=01468">Echo</a> <a href="https://yourwater.oregon.gov/wildfire-pws.php?pwsno=00605">Mountain</a>, <a href="https://yourwater.oregon.gov/inventory.php?pwsno=00257">Lionshead</a> and <a href="https://yourwater.oregon.gov/wildfire-pws.php?pwsno=00857">Almeda</a> fires in Oregon, and the <a href="https://www.slvwd.com/water-quality/pages/czu-fire-water-quality-info">CZU</a> <a href="http://www.bigbasinwater.com/">Lightning</a> <a href="https://www.countyofnapa.org/CivicAlerts.aspx?AID=191">Complex</a>, <a href="https://doi.org/10.1002/aws2.1183">Camp</a> and <a href="https://doi.org/10.1002/aws2.1183">Tubbs</a> fires in California. Thousands of private <a href="https://doi.org/10.1007/s11069-021-04714-9">wells</a> have been affected too.</p>
<p>Being exposed to contaminated water can cause immediate harm, such as headaches, nausea, dizziness and vomiting. Short-term exposure to 26 parts per billion or more of <a href="https://engineering.purdue.edu/PlumbingSafety/resources/Benzene-Levels-in-Water.pdf">benzene</a>, a carcinogen, may cause a decrease in white blood cells that protect the body from infectious disease. Multiple fires have caused drinking water to exceed this level. A <a href="https://doi.org/10.1002/aws2.1183">variety</a> of other chemicals can exceed safe drinking water exposure limits too in the absence of benzene.</p>
<p><iframe id="HfF2M" class="tc-infographic-datawrapper" src="https://datawrapper.dwcdn.net/HfF2M/3/" height="400px" width="100%" style="border: none" frameborder="0"></iframe></p>
<h2>Households are not being adequately warned</h2>
<p>In a <a href="https://doi.org/10.1007/s11069-021-04714-9">survey of 233 households</a> affected by water contamination, we found people reported high levels of anxiety and stress linked to the water problems. Nearly half had installed in-home water treatment because of uncertainty about the water. Eighty-five percent had looked for other water sources, such as bottled water.</p>
<p>In some cases, <a href="https://doi.org/10.1007/s11069-021-04714-9">we found</a> that advice from government agencies placed households at greater risk of harm. It has sometimes left people exposed to chemicals, caused them to needlessly spend money and given them a false sense of security. Certified in-home water treatment devices, for example, are tested only to bring down 15 parts per billion of benzene to less than 5 parts per billion, the federal standard. These devices are not tested to treat <a href="https://19january2017snapshot.epa.gov/sites/production/files/2015-06/documents/tclp.pdf">hazardous waste-scale</a> contaminated water that’s been found after wildfires.</p>
<p>Following the 2020 CZU Lightning Complex Fire near Santa Cruz, California, a local health department correctly <a href="https://www.santacruzcounty.us/Portals/6/Env_Health/CZU_Fire/WaterWellFireReturn.pdf">warned private well</a> owners not to use their water and to test it, but a nearby damaged water system and the state did not warn 17,000 people against <a href="https://www.slvwd.com/sites/g/files/vyhlif1176/f/uploads/slvwd_dnd-dnb_notice_approved_completed_8.29.2020_0.pdf">bathing</a> in the contaminated water. It was only after test results proved the water had been unsafe all along that the system owner and state advised against <a href="https://www.slvwd.com/sites/g/files/vyhlif1176/f/uploads/slvwd_faq_dnd-dnb_notice_swrcb_approved_9.6.2020.pdf?fbclid=IwAR0OaoX5YThw7chVdfDV8zOrUpun8hDCoStfjyJHJ3OdRFDifSPPHPC45Hk">bathing</a> in it.</p>
<p>In Oregon, some damaged systems encouraged people to <a href="http://www.cityoftalent.org/News.asp?NewsID=280">boil</a> their drinking water, later finding that the water had benzene in it.</p>
<p>After the 2018 Camp Fire that devastated Paradise, California, the local health department correctly warned the entire county not to use or try to <a href="https://buttecountyrecovers.org/butte-county-health-officer-issues-water-quality-advisory-for-residents-in-burn-affected-areas/">treat the drinking water</a>, which had contamination above EPA’s hazardous waste limit. But one water system and the state encouraged 13,000 people to try to <a href="https://www.waterboards.ca.gov/drinking_water/programs/documents/benzenecustomeradvisoryfinal.pdf">treat it themselves</a>.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/398673/original/file-20210504-13-9qjbaj.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Photos showing examples of fire damage to water systems" src="https://images.theconversation.com/files/398673/original/file-20210504-13-9qjbaj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/398673/original/file-20210504-13-9qjbaj.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=855&fit=crop&dpr=1 600w, https://images.theconversation.com/files/398673/original/file-20210504-13-9qjbaj.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=855&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/398673/original/file-20210504-13-9qjbaj.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=855&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/398673/original/file-20210504-13-9qjbaj.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=1075&fit=crop&dpr=1 754w, https://images.theconversation.com/files/398673/original/file-20210504-13-9qjbaj.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=1075&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/398673/original/file-20210504-13-9qjbaj.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=1075&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Pipes, water meters and meter covers after wildfires destroyed them.</span>
<span class="attribution"><a class="source" href="https://awwa.onlinelibrary.wiley.com/doi/full/10.1002/aws2.1183">Caitlin Proctor, Amisha Shah, David Yu, and Andrew Whelton/Purdue University</a>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>In all of these cases, the U.S. Environmental Protection Agency chose not to compel water utilities to explicitly <a href="https://nepis.epa.gov/Exe/ZyPDF.cgi?Dockey=P100529C.txt#_ga=1.47005794.472891366.1423060476%22%22">notify</a> customers about the water contamination and its risk.</p>
<p>Communities have received other bad information:</p>
<ul>
<li>Commercial <a href="https://doi.org/10.1007/s11069-021-04714-9">labs</a> and government officials recommended flushing faucets for 5 to 15 minutes before collecting a water sample, thereby dumping out the contaminated plumbing water meant for testing.</li>
<li>Homeowners were <a href="https://www.waterboards.ca.gov/drinking_water/programs/documents/benzenecustomeradvisoryfinal.pdf">led</a> to believe a single cold water sample at the kitchen sink would determine if the hot water system and property service line was contaminated. It cannot.</li>
<li>People were <a href="https://www.oregon.gov/oha/PH/HEALTHYENVIRONMENTS/DRINKINGWATER/PREPAREDNESS/Documents/customer-guidance-wildfire.pdf">led</a> to believe that benzene water testing would determine if any other chemicals were present above safe limits. This is not possible.</li>
</ul>
<h2>What to look for after a nearby fire</h2>
<p>Signs of potential contamination after a nearby wildfire could be loss of water pressure, discolored water, heat damage to water systems inside and outside buildings, and broken and leaking pipes, valves and hydrants.</p>
<p>Drinking water should be assumed to be chemically unsafe until proven otherwise.</p>
<p>Once a system is contaminated, cleanup can take months. The water system will have to be flushed and tested regularly to track down <a href="https://www.fema.gov/sites/default/files/2020-07/fema_DRRA-1205-implementation-job-aid.pdf">contamination</a>. Health departments should also issue guidance on how to test private wells and plumbing.</p>
<p>When testing plumbing, include the property service line as well as the hot and cold water lines. Before collecting a water sample, the water must sit long enough in the plumbing so contamination can be found – 72 hours was the Tubbs Fire and Camp Fire standard. Tests should look for more than benzene.</p>
<figure class="align-center ">
<img alt="Illustration of pipes in a community" src="https://images.theconversation.com/files/398719/original/file-20210504-18-3s947b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/398719/original/file-20210504-18-3s947b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=338&fit=crop&dpr=1 600w, https://images.theconversation.com/files/398719/original/file-20210504-18-3s947b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=338&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/398719/original/file-20210504-18-3s947b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=338&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/398719/original/file-20210504-18-3s947b.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=424&fit=crop&dpr=1 754w, https://images.theconversation.com/files/398719/original/file-20210504-18-3s947b.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=424&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/398719/original/file-20210504-18-3s947b.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=424&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Building water systems can receive contaminated drinking water from public water systems and private wells.</span>
<span class="attribution"><span class="source">Andrew Whelton/Purdue University</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<h2>Who can help?</h2>
<p>Many of the <a href="https://doi.org/10.1007/s11069-021-04714-9">critical public health risks</a> identified in our new study can be addressed by public health departments with financial support from state and local agencies.</p>
<p>Public health departments often have experience responding to water problems, such as legionella outbreaks, and can provide technical advice about both chemical exposures, building plumbing and private drinking water wells.</p>
<p>[<em>Deep knowledge, daily.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=deepknowledge">Sign up for The Conversation’s newsletter</a>.]</p><img src="https://counter.theconversation.com/content/159527/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew J. Whelton received funding from the U.S. National Science Foundation, Paradise Irrigation District, U.S. Environmental Protection Agency, Paradise Rotary Foundation, and Water Research Foundation.</span></em></p>An increasing number of communities are discovering dangerous contamination in their water systems weeks or months after fires.Andrew J. Whelton, Associate Professor of Civil, Environmental & Ecological Engineering, Director of the Healthy Plumbing Consortium and Center for Plumbing Safety, Purdue UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1595372021-04-28T09:06:33Z2021-04-28T09:06:33ZWe’re all ingesting microplastics at home, and these might be toxic for our health. Here are some tips to reduce your risk<figure><img src="https://images.theconversation.com/files/397474/original/file-20210428-27-1aathhr.jpg?ixlib=rb-1.1.0&rect=0%2C0%2C4288%2C2848&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>Australians are eating and inhaling significant numbers of tiny plastics at home, our <a href="https://doi.org/10.1016/j.envpol.2021.117064">new research</a> shows.</p>
<p>These “microplastics”, which are derived from petrochemicals extracted from oil and gas products, are settling in dust around the house. </p>
<p>Some of these particles are toxic to humans — they can carry carcinogenic or mutagenic chemicals, meaning they potentially cause cancer and/or damage our DNA. </p>
<p>We still don’t know the true impact of these microplastics on human health. But the good news is, having hard floors, using more natural fibres in clothing, furnishings and homewares, along with vacuuming at least weekly can reduce your exposure.</p>
<h2>What are microplastics?</h2>
<p>Microplastics are plastic particles less than five millimetres across. They come from a range of household and everyday items such as the clothes we wear, home furnishings, and food and beverage packaging.</p>
<p>We know microplastics are pervasive outdoors, reaching remote and inaccessible locations such as the <a href="https://advances.sciencemag.org/content/5/8/eaax1157">Arctic</a>, the <a href="https://www.geochemicalperspectivesletters.org/article1829/#">Mariana Trench</a> (the world’s deepest ocean trench), and the <a href="https://doi.org/10.1016/j.envpol.2019.07.005">Italian Alps</a>.</p>
<p>Our study demonstrates it’s an inescapable reality that we’re living in a sea of microplastics — they’re in our food and drinks, our oceans, and our homes.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/we-estimate-up-to-14-million-tonnes-of-microplastics-lie-on-the-seafloor-its-worse-than-we-thought-146403">We estimate up to 14 million tonnes of microplastics lie on the seafloor. It's worse than we thought</a>
</strong>
</em>
</p>
<hr>
<h2>What we did and what we found</h2>
<p>While research has focused mainly on microplastics in the natural environment, a <a href="https://doi.org/10.1021/acs.est.0c00087">handful</a> of <a href="https://doi.org/10.1016/j.envpol.2016.12.013">studies</a> have looked at how much we’re exposed to indoors.</p>
<p>People spend up to <a href="https://doi.org/10.1038/sj.jea.7500165">90% of their time indoors</a> and therefore the greatest risk of exposure to microplastics is in the home. </p>
<p>Our study is the first to examine how much microplastic we’re exposed to in Australian homes. We analysed dust deposited from indoor air in 32 homes across Sydney over a one-month period in 2019. </p>
<p>We <a href="https://www.360dustanalysis.com">asked members</a> <a href="https://www.ausmap.org/">of the public</a> to collect dust in specially prepared glass dishes, which we then analysed.</p>
<figure class="align-center ">
<img alt="A graphic showing how microplastics suspended in a home" src="https://images.theconversation.com/files/397448/original/file-20210428-15-1qxf69g.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397448/original/file-20210428-15-1qxf69g.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=424&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397448/original/file-20210428-15-1qxf69g.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=424&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397448/original/file-20210428-15-1qxf69g.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=424&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397448/original/file-20210428-15-1qxf69g.jpeg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=533&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397448/original/file-20210428-15-1qxf69g.jpeg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=533&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397448/original/file-20210428-15-1qxf69g.jpeg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=533&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Here’s how microplastics can be generated, suspended, ingested and inhaled inside a house.</span>
<span class="attribution"><a class="source" href="https://www.copperplatedesign.com.au/">Monique Chilton</a>, <span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>We found 39% of the deposited dust particles were microplastics; 42% were natural fibres such as cotton, hair and wool; and 18% were transformed natural-based fibres such as viscose and cellophane. The remaining 1% were film and fragments consisting of various materials.</p>
<p>Between 22 and 6,169 microfibres were deposited as dust per square metre, each day. </p>
<p>Homes with carpet as the main floor covering had nearly double the number of petrochemical-based fibres (including <a href="https://www.acplasticsinc.com/informationcenter/r/7-different-types-of-plastic-and-how-they-are-used">polyethylene, polyamide and polyacrylic</a>) than homes without carpeted floors.</p>
<p>Conversely, <a href="http://cameo.mfa.org/wiki/Polyvinyl_chloride_fiber#:%7E:text=Polyvinyl%20chloride%20fiber%2C%20200x%20polarized,as%20vinyon%20fibers%20or%20chlorofibers.">polyvinyl fibres</a> (synthetic fibres made of vinyl chloride) were two times more prevalent in homes without carpet. This is because the coating applied to hard flooring degrades over time, producing polyvinyl fibres in house dust. </p>
<h2>Microplastics can be toxic</h2>
<p>Microplastics can carry a range of <a href="https://doi.org/10.1021/es0010498">contaminants</a> such as trace metals and some potentially <a href="https://doi.org/10.1016/j.scitotenv.2020.142427">harmful organic chemicals</a>. </p>
<p>These chemicals can leach from the plastic surface once in the body, increasing the potential for toxic effects. Microplastics can have <a href="https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex%3A32008R1272">carcinogenic</a> properties, meaning they potentially cause cancer. They can also be mutagenic, meaning they can damage DNA.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/why-ocean-pollution-is-a-clear-danger-to-human-health-152641">Why ocean pollution is a clear danger to human health</a>
</strong>
</em>
</p>
<hr>
<p>However, even though some of the microplastics measured in our study are composed of potentially <a href="https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=celex%3A32008R1272">carcinogenic and/or mutagenic compounds</a>, the actual risk to human health is unclear.</p>
<p>Given the pervasiveness of microplastics not only in homes but in <a href="https://doi.org/10.1016/j.jhazmat.2020.124004">food and beverages</a>, the crucial next step in this research area is to establish what, if any, are <a href="https://doi.org/10.1371/journal.pbio.2003066">safe levels of exposure</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/youre-eating-microplastics-in-ways-you-dont-even-realise-97649">You're eating microplastics in ways you don't even realise</a>
</strong>
</em>
</p>
<hr>
<h2>How much are we exposed to? And can this be minimised?</h2>
<p>Roughly a quarter of all of the fibres we recorded were less than 250 micrometres in size, meaning they can be inhaled. This means we can be internally exposed to these microplastics and any contaminants attached to them.</p>
<p>Using human exposure models, we calculated that inhalation and ingestion rates were greatest in children under six years old. This is due to their lower relative body weight, smaller size, and higher breathing rate than adults. What’s more, young children typically have more contact with the floor, and tend to put their hands in their mouths more often than adults. </p>
<figure class="align-center ">
<img alt="Small bits of plastic floating in the sea" src="https://images.theconversation.com/files/397465/original/file-20210428-23-1tlwht3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/397465/original/file-20210428-23-1tlwht3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/397465/original/file-20210428-23-1tlwht3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/397465/original/file-20210428-23-1tlwht3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/397465/original/file-20210428-23-1tlwht3.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/397465/original/file-20210428-23-1tlwht3.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/397465/original/file-20210428-23-1tlwht3.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Microplastics are found not only in the sea, but in our food, beverages, and our homes.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>Children under six inhale around three times more microplastics than the average — 18,000 fibres, or 0.3 milligrams per kilogram of body weight per year. They would also ingest on average 6.1 milligrams of microplastics in dust per kg of body weight per year.</p>
<p>For a five-year-old, this would be equivalent to eating a garden pea’s worth of microplastics over the course of a year. But for many of these plastics there is no established safe level of exposure.</p>
<p>Our study indicated there are effective ways to minimise exposure.</p>
<p>First is the choice of flooring, with hard surfaces, including polished wood floors, likely to have fewer microplastics than carpeted floors. </p>
<p>Also, how often you clean makes a difference. Vacuuming floors at least weekly was associated with less microplastics in dust than those that were less frequently cleaned. So get cleaning!</p><img src="https://counter.theconversation.com/content/159537/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Mark Patrick Taylor received research support for this project via an Australian Government Citizen
Science Grant, CSG55984, ‘Citizen insights to the composition and risks of household dust’ (the DustSafe project).
Participant questionnaires for collecting meta-data were approved by Macquarie University’s ethics panel, project ID 2446. Cochlear Sydney provided access to their Nicolet iN10-MX FTIR instrument to undertake the research.</span></em></p><p class="fine-print"><em><span>Neda Sharifi Soltani receives funding from the Australian Government as a Research Training
Program (RTP) scholarship no.2017678. </span></em></p><p class="fine-print"><em><span>Scott Wilson receives funding from the Total Environment Centre and NSW EPA to conduct research on microplastics in the environment. He is the Research Director of the Australian Microplastic Assessment Project (AUSMAP), which is a citizen science focussed program. </span></em></p>We analysed the dust in 32 homes across Sydney, and found significant levels of microplastics. But having hard, non-varnished floors and vacuuming at least weekly might help.Mark Patrick Taylor, Professor of Environmental Science and Human Health, Macquarie UniversityNeda Sharifi Soltani, Academic Casual, Macquarie UniversityScott P. Wilson, Macquarie UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1245692019-10-14T11:42:39Z2019-10-14T11:42:39ZCanada needs an Alcohol Act to address the damage caused by this deadly carcinogen<figure><img src="https://images.theconversation.com/files/296284/original/file-20191009-3887-ftw3e3.jpg?ixlib=rb-1.1.0&rect=192%2C185%2C4276%2C2768&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Research estimates that each year some 15,000 deaths, 90,000 hospital admissions and 240,000 years of life lost are directly attributable to alcohol use. </span> <span class="attribution"><span class="source">(Shutterstock)</span></span></figcaption></figure><p>With the <a href="https://theconversation.com/the-opioid-crisis-is-not-about-pain-112296">opioid overdose crisis</a>, concern about <a href="https://theconversation.com/vaping-is-an-urgent-threat-to-public-health-112131">teens using electronic cigarettes</a> and our fascination with the <a href="https://theconversation.com/a-campaign-promise-kept-canadas-modestly-successful-cannabis-legalization-122380">legalization of cannabis</a>, our most dangerous legal drug continues to be ignored by Canadian policy-makers. </p>
<p>We have strong legislation and regulation governing tobacco and cannabis sales, marketing and labelling, but the federal government has been asleep at the wheel for years on alcohol policy. Meanwhile, some provincial governments are <a href="https://toronto.citynews.ca/2019/07/08/torontos-top-doctor-sounds-alarm-on-provinces-loosened-alcohol-regulations/">aggressively loosening restrictions and lowering prices</a>.</p>
<p>From a public health and safety perspective, this makes absolutely no sense. In 2018, using a <a href="https://www.ccsa.ca/sites/default/files/2019-04/CSUCH-Canadian-Substance-Use-Costs-Harms-Report-2018-en.pdf">Health Canada-funded study</a>, we estimated each year some 15,000 deaths, 90,000 hospital admissions and 240,000 years of life lost are directly attributable to alcohol use. </p>
<p>Along with impacts on productivity and crime, the <a href="https://www.ccsa.ca/sites/default/files/2019-04/CSUCH-Canadian-Substance-Use-Costs-Harms-Infographic-2018-en.pdf">annual economic toll of $15 billion</a> was greater than that from either tobacco use or from cannabis, opioids and all illegal substances combined. On the other side of the ledger, federal and provincial governments collected less than <a href="https://www.uvic.ca/research/centres/cisur/assets/docs/infographic-cisur-canadian-alcohol-policy-evaluation.pdf">$11 billion in revenues from alcohol in the same year</a>.</p>
<h2>Canadians kept in the dark</h2>
<p>The World Health Organization has <a href="https://monographs.iarc.fr/list-of-classifications">classified alcohol as a Class 1 carcinogen</a>, along with asbestos and tobacco, for decades. However, surveys find that only <a href="http://www.cancer.ca/en/about-us/news/on/2016/february/story4/?region=on">one third of Canadians are aware of this risk</a>.</p>
<p>Our attempt to study the value of placing this information on warning labels in government liquor stores in the Yukon <a href="https://www.cbc.ca/news/canada/north/yukon-liquor-label-backlash-1.4466330">was shut down in late 2017</a> following veiled legal threats from alcohol producers. The Yukon government backed down and the cancer labels were removed.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/296273/original/file-20191009-3846-1t2nnsd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/296273/original/file-20191009-3846-1t2nnsd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=387&fit=crop&dpr=1 600w, https://images.theconversation.com/files/296273/original/file-20191009-3846-1t2nnsd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=387&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/296273/original/file-20191009-3846-1t2nnsd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=387&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/296273/original/file-20191009-3846-1t2nnsd.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=486&fit=crop&dpr=1 754w, https://images.theconversation.com/files/296273/original/file-20191009-3846-1t2nnsd.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=486&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/296273/original/file-20191009-3846-1t2nnsd.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=486&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Alcohol, cannabis and tobacco products are labelled very differently.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Since then, the federal government has taken no action to help inform consumers about the cancer risk from alcohol, to offer guidelines for low-risk drinking or even provide information that is required on all food and drink products — such as calorie content, serve sizes or nutritional information. This is despite the fact that another one of our recent studies <a href="https://doi.org/10.3148/cjdpr-2018-046">found that Canadian drinkers consumed 11 per cent of their daily calories in the form of alcohol</a>.</p>
<p>The federal Liberal government recently woke up to the fact they were losing a fortune in tax revenues by not adjusting alcohol excise tax rates each year to the cost of living. </p>
<p>In late 2017, despite strenuous opposition from industry groups, they passed legislation to ensure <a href="https://www.canada.ca/en/revenue-agency/services/forms-publications/publications/edrates/excise-duty-rates.html">alcohol excise taxes were adjusted</a> to keep up with the cost of living for the first time since 1986. Alcohol industry lobbyists have attempted to mislead the public by characterizing these small indexed rises as “tax hikes” when they are simply maintaining the value of these taxes at the same level.</p>
<p>In a soon-to-be-released report, we estimate that the federal government has lost at least $10.5 billion by failing to adjust alcohol taxes with inflation. As a result, alcohol consumption is now about four per cent higher, leading to over 300 extra preventable deaths and almost 4,000 preventable hospitalizations per year.</p>
<h2>Death and (alcohol) taxes</h2>
<p>While talking of taxes may cause one’s eyes to glaze over, the real-world implications are deadly. One yawning loophole in the tax system encourages the manufacture, sale and consumption of cheap coolers — such as a malt-based product with the perhaps appropriate name of FCKDUP that contributed to the <a href="https://www.ctvnews.ca/canada/after-quebec-teen-s-death-convenience-store-pulls-sugary-high-alcohol-drink-1.3827525">tragic death of a 14-year-old girl last year</a>. This product had an 11.9 per cent alcohol content, delivering more than four standard drinks in one 568-millilitre container, retailing at less than a dollar per standard drink.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1110914086940876800"}"></div></p>
<p>In the aftermath of this tragedy, there was little discussion of the reason for this low price and hence attractiveness to teenagers: it was taxed at the same rate as beer without any regard for alcoholic strength because beer taxes in Canada are “flat” — they do not increase as alcohol content increases.</p>
<h2>Time for an Alcohol Act</h2>
<p>There is no federal Alcohol Act in Canada, unlike the case with <a href="https://laws-lois.justice.gc.ca/eng/acts/c-24.5/">cannabis</a>, <a href="https://www.canada.ca/en/health-canada/services/health-concerns/tobacco/legislation/federal-laws/tobacco-act.html">tobacco</a> and <a href="https://laws-lois.justice.gc.ca/eng/acts/c-38.8/">illegal substances</a>. </p>
<p>Doubtless political parties campaigning in our forthcoming federal election will make all manner of policy commitments for getting tough on vaping nicotine, which is associated with no known deaths in Canada. We’ve already seen various campaign promises being made on how to <a href="https://globalnews.ca/news/5895146/canada-election-federal-parties-opioid-overdose-crisis/">tackle the opioid overdose crisis</a>. And while the death toll from this crisis is indeed grim, protecting Canadians’ health and safety would be at least as equally well-served by a comprehensive set of evidence-based strategies and laws to mitigate the more substantial but overlooked harms from alcohol.</p>
<p>As we recommended in our <a href="https://www.uvic.ca/research/centres/cisur/assets/docs/report-cape-fed-en.pdf">evaluation of federal alcohol policies</a> earlier this year, a national strategy needs to be developed independently from alcohol industry interests to ensure consumers are informed about risks and harm reduction strategies, that prices reflect alcohol strength and advertising codes apply to the new digital media.</p>
<p>For too long, complacency and a strong industry voice has led to a lack of effective policies and supporting legislation around alcohol in Canada. Canadians deserve to be informed about alcohol’s risks and to have evidence-based regulations and laws to reduce these. </p>
<p>It’s time for our next federal government to step up with an Alcohol Act and a national strategy to reduce the harms from what continues to be our favourite, but most costly, recreational drug.</p>
<p>[ <em><a href="https://theconversation.com/ca/newsletters?utm_source=TCCA&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=expertise">Expertise in your inbox. Sign up for The Conversation’s newsletter and get a digest of academic takes on today’s news, every day.</a></em> ]</p><img src="https://counter.theconversation.com/content/124569/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Tim Stockwell receives funding from the Canadian Institutes for Health Research, Health Canada, Alko, Systembolaget, National Drug Research Institute (Australia), the BC Ministry of Health and Public Health Agency of Canada.</span></em></p>Alcohol is classified by the World Health Organization as a Class 1 carcinogen. Our next federal government must step up with an Alcohol Act and a strategy to reduce harms from this recreational drug.Tim Stockwell, Director, Canadian Institute for Substance Use Research and Professor of Psychology, University of VictoriaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1127712019-03-07T19:06:50Z2019-03-07T19:06:50ZResearch Check: do we need to worry about glyphosate in our beer and wine?<figure><img src="https://images.theconversation.com/files/262573/original/file-20190307-100787-1qzaux0.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Research out of the US tested different varieties of beer and wine for the presence of glyphosate – but there's lots to consider when interpreting the findings.</span> <span class="attribution"><span class="source">From shutterstock.com</span></span></figcaption></figure><p>Glyphosate is back in the news again. The common weed killer, which has previously <a href="https://medium.com/@gidmk/glyphosate-isnt-giving-you-cancer-f4597a35f87e">attracted controversy</a> for its possible link to cancer, has been found in beer and wine.</p>
<p>Researchers in the US tested 15 different types of beer and five different types of wine, <a href="https://uspirg.org/sites/pirg/files/reports/WEB_USP_Glyphosate-pesticide-beer-and-wine_REPORT_022619.pdf">finding traces</a> of the pesticide in 19 out of the 20 beverages.</p>
<p><div data-react-class="Tweet" data-react-props="{"tweetId":"1100908528133386241"}"></div></p>
<p>So how much should we be worried? Hint: not at all. The amount detected was well below a level which could cause harm. And there are insufficient details in the methods section to feel confident about the results.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/stop-worrying-and-trust-the-evidence-its-very-unlikely-roundup-causes-cancer-104554">Stop worrying and trust the evidence: it's very unlikely Roundup causes cancer</a>
</strong>
</em>
</p>
<hr>
<h2>How was this study conducted?</h2>
<p>One of the first things I do when evaluating a piece of research is to check the methods – so how the researchers went about collecting the data. What I found didn’t fill me with confidence.</p>
<p>The authors say they set up their experiment based on a technique called a <a href="https://www.chemguide.co.uk/analysis/masspec/howitworks.html">mass spectroscopy method</a>. This methodology has been used to measure the <a href="https://journals.tdl.org/regsci/index.php/regsci/article/view/15">quantities of glyphosate in milk</a> (but not alcoholic drinks). Mass spectroscopy is a very sensitive and specific method, and the authors quote the concentrations that can be reliably detected in milk with this approach.</p>
<p>But the method they actually used is called <a href="https://en.wikipedia.org/wiki/ELISA">enzyme linked immunosorbent assay</a> (ELISA). Importantly, you can’t use the concentrations that can be reliably detected with the mass spectroscopy to describe ELISA sensitivity. They’re not compatible.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/262577/original/file-20190307-100802-10j6abc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/262577/original/file-20190307-100802-10j6abc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=401&fit=crop&dpr=1 600w, https://images.theconversation.com/files/262577/original/file-20190307-100802-10j6abc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=401&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/262577/original/file-20190307-100802-10j6abc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=401&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/262577/original/file-20190307-100802-10j6abc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/262577/original/file-20190307-100802-10j6abc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/262577/original/file-20190307-100802-10j6abc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Glyphosate is the pesticide which makes up many weed killers.</span>
<span class="attribution"><span class="source">From shutterstock.com</span></span>
</figcaption>
</figure>
<p>ELISA is sensitive, but typically not as sensitive as mass spectroscopy, which uses an entirely different physical method to measure glyphosate. </p>
<p>ELISA also has issues of cross contamination. Biological samples for glyphosate measurement, whether ELISA or mass spectroscopy, need careful sample preparation to avoid cross-reaction with any other materials in the sample such as the common amino acid glycine, which looks quite similar to glyphosate and is present in much higher quantities. But the authors didn’t give any detail about the sample preparation used.</p>
<p>These issues make it difficult to be confident in the results.</p>
<p>We’ve seen this before with <a href="https://www.momsacrossamerica.com/glyphosate_testing_results">claims of detection of glyphosate in breast milk</a>, which <a href="https://www.ncbi.nlm.nih.gov/pubmed/27030536">could not be duplicated</a>. So given the lack of detail around the methodologies used, we should be cautious about taking these figures at face value.</p>
<h2>What did they find?</h2>
<p>For the sake of argument, let’s accept the researchers’ values and take a look at what they mean.</p>
<p>The highest level of glyphosate they measured was 51.4 parts per billion in one wine (in most of the beverages they found much less). That’s equivalent to 0.0514 miligrams per litre (mg/L). </p>
<p>The authors cite California’s Office of Environmental Health Hazard’s proposed “No Significant Risk Level” for glyphosate consumption of <a href="https://oehha.ca.gov/media/downloads/crnr/glyphosatensrlfsor041018.pdf">0.02 mg/kg body weight/day</a>. The limits are based on body weight, so a heavier person can be exposed to more than a person who weighs less, taking into account body volume and metabolism.</p>
<p>This is much lower than the EU Food Safety Authorities’ and <a href="https://apvma.gov.au/node/26596">Australia’s regulatory allowable daily intake</a> of 0.3 mg/kg body weight/day.</p>
<p>But again, for argument’s sake, let’s use the Californian proposed limits and look at the wine in which the researchers measured the highest amount of glyphosate. With those limits, an average Australian male weighing 86kg would need to drink <em>33 litres</em> of this wine every day to reach the risk threshold. A 60kg person would need to drink 23 litres of this wine each day.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/drink-drank-drunk-what-happens-when-we-drink-alcohol-in-four-short-videos-100206">Drink, drank, drunk: what happens when we drink alcohol in four short videos</a>
</strong>
</em>
</p>
<hr>
<p>If you’re drinking 33 litres of wine a day you have much, much bigger problems than glyphosate. </p>
<p>Alcohol is a <a href="https://canceraustralia.gov.au/publications-and-resources/position-statements/lifestyle-risk-factors-and-primary-prevention-cancer/lifestyle-risk-factors/alcohol">class 1 carcinogen</a>. Those levels of alcohol consumption would give you a <a href="https://www.cancer.gov/about-cancer/causes-prevention/risk/alcohol/alcohol-fact-sheet#q3">five times greater risk</a> of head, neck and oesophageal cancer (and an increased risk of other cancers). The risk of glyphosate causing cancer is nowhere near these levels. The irony is palpable.</p>
<p>This isn’t even taking into account the likelihood of dying of alcohol poisoning by drinking at this level – which will get you well before any cancer.</p>
<p>And that’s using the highly conservative Californian limits. Using the internationally accepted limits, an average adult male would have to drink over 1,000 litres of wine a day to reach any level of risk.</p>
<h2>So how should we interpret the results?</h2>
<p>The report does not contain a balanced representation of the risks of glyphosate.</p>
<p>They cite the International Agency for Research on Cancer’s finding of <a href="https://monographs.iarc.fr/iarc-monographs-on-the-evaluation-of-carcinogenic-risks-to-humans-4/">glyphosate as class 2</a> (probably) carcinogenic (alcohol is class 1, a known carcinogen). </p>
<p>But they don’t mention the <a href="https://www.efsa.europa.eu/en/efsajournal/pub/4302">European Food Safety authority finding</a> that glyphosate posed no risk of cancer, or the <a href="https://echa.europa.eu/documents/10162/22863068/glyphosate_jmpr_en.pdf/7dbc05a9-d81b-054d-e750-0f762b579fe7">WHO Joint Meeting on Pesticide Residues report</a> showing no significant cancer risk to consumers under normal exposure.</p>
<p>They cite a paper on glyphosate supposedly increasing the <a href="https://www.ncbi.nlm.nih.gov/pubmed/23756170">rate of breast cancer cell growth</a>, but not <a href="https://www.scireslit.com/Toxicology/AJTCR-ID23.pdf">the papers</a> that find <a href="https://journals.tdl.org/regsci/index.php/regsci/article/view/15">no such thing</a>. </p>
<p>They don’t cite the most important study of human exposure, the <a href="https://academic.oup.com/jnci/article/110/5/509/4590280">Agricultural Health Study</a> which is the largest and longest study of the effect of glyphosate use. This study found no significant increase in cancer in highly exposed users.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="https://theconversation.com/research-check-can-even-moderate-drinking-cause-brain-damage-79036">Research Check: can even moderate drinking cause brain damage?</a>
</strong>
</em>
</p>
<hr>
<p>The “report” claiming that there is glyphosate in wine and beer provides inadequate information to judge the accuracy of the claimed detection, and does not put the findings in context of exposure and risk.</p>
<p>Even taking their reported levels at face value, the risk from alcohol consumption vastly outweighs any theoretical risk from glyphosate. Their discussion does not fairly consider the evidence and is weighted towards casting doubt over the safety of glyphosate.</p>
<p>So you may enjoy your beer and wine (in moderation), without fear of glyphosate.</p>
<h2>Blind peer review</h2>
<p>This is a fair and accurate assessment of the study and its findings. That said, it is prudent for the scientific community to remain attentive to changes within the food supply and issues of potential risk to public health. Considering the increasing use of glyphosate by the food industry, we need continued diligence in this area. <strong>– Ben Desbrow</strong></p>
<hr>
<p><em><a href="https://theconversation.com/au/topics/research-check-25155">Research Checks</a> interrogate newly published studies and how they’re reported in the media. The analysis is undertaken by one or more academics not involved with the study, and reviewed by another, to make sure it’s accurate.</em></p><img src="https://counter.theconversation.com/content/112771/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Ian Musgrave has previously received funding from the National Health and Medical Research Council to study adverse reactions to herbal medicines and has previously been funded by the Australian Research Council to study potential natural product treatments for Alzheimer's disease. He has collaborated with SA water on studies of cyanobacterial toxins and their implication for drinking water quality. He does not consult or work for any Agricultural crop company. He did give an invited talk on glyphosate at the 5th South Australia Weeds Conference, for which he received a rather nice muffin and a free cup of coffee.</span></em></p><p class="fine-print"><em><span>Ben Desbrow does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The amount of alcohol you’d have to drink before glyphosate posed even a negligible risk would harm you well before the glyphosate would.Ian Musgrave, Senior lecturer in Pharmacology, University of AdelaideLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/989992018-07-18T15:12:01Z2018-07-18T15:12:01ZHealth clubs using tanning beds to attract members despite cancer risks, new study shows<figure><img src="https://images.theconversation.com/files/224982/original/file-20180626-112598-pyftsg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Individuals using indoor tanning are exposed to two types of UV rays -- UVA and UVB -- that damage skin and DNA and can lead to cancer, including the deadliest one: melanoma. Young users are most at risk.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/young-beautiful-latin-lady-lying-on-88135858?src=BpuO-_EIkjDyv8-TxSQmZA-1-12">By Rido/shutterstock.com</a></span></figcaption></figure><p>I drove past Planet Fitness on the way to my 10-year-old’s gymnastics class and had to chuckle at their sign advertising free pizza as part of a new member promotion. I decided to use this as a teaching moment, explaining to my daughter why we should avoid using junk food as a reward for exercise. This is one of many lectures she has heard from her mom, a cancer prevention scientist. </p>
<p>When I decided to look a little deeper into what gyms are offering to entice people to sign up, pizza turned out to be the least of my concerns. Many gyms offer access to tanning beds, a <a href="https://doi.org/10.1002/ijc.22453">known carcinogen</a>, to their patrons. We would be astounded if gyms provided tobacco to patrons, so we must pose serious questions to gyms who provide ultraviolet radiation.</p>
<p>The comparison of tobacco and tanning beds might seem like hyperbole, but it is not. They are both rated <a href="https://doi.org/10.1002/ijc.22453">group 1 carcinogens</a> and <a href="http://doi.org/10.1001/jamadermatol.2013.6896">research</a> shows that we now have more cancers related to tanning beds than cancers related to tobacco.</p>
<h2>Gyms are supporting the tanning industry</h2>
<p>To explore how pervasive these gym-tanning salons were, I asked my research assistant to call every Planet Fitness, Anytime Fitness and Gold’s Gym in Massachusetts and Connecticut to find out just how many had tanning beds. Of the 167 gyms we found on Google, 66 percent offer patrons tanning beds, with Planet Fitness the biggest offender where a whopping 100 percent of their franchises have tanning beds. In total, these gyms have 408 tanning beds. <a href="https://jamanetwork.com/journals/jamadermatology/fullarticle/2687548">Extrapolating this to all 50 states</a> would mean that these three gym chains alone house over 10,000 tanning beds nationwide. That’s an equivalent capacity to 1,600 tanning salons. The tanning industry must be thrilled.</p>
<p>Making the presence of tanning beds in gyms even more shocking is a recent <a href="https://doi.org/10.1001/jamainternmed.2016.1548">study</a> showing that people who are physically active are at increased risk for melanoma, the deadly form of skin cancer. <a href="https://doi.org/10.1093/jnci/dju112">Tanning bed use</a> is a major risk factor for melanoma, which is now the <a href="https://www.cancer.org/content/dam/cancer-org/research/cancer-facts-and-statistics/annual-cancer-facts-and-figures/2018/cancer-facts-and-figures-2018.pdf">third most prevalent cancer</a> in women under 49 years old, a popular gym demographic. Why would we put a carcinogen in the facility frequented by people who are at increased risk for the very cancer it causes? </p>
<p><a href="https://jamanetwork.com/journals/jamadermatology/fullarticle/2687548">I decided to conduct a study</a> to learn more about people who use those gym tanning beds. We surveyed 636 people who have ever used a tanning bed in their life and found that about a quarter of them had tanned in gyms. When I compared the group who had tanned in a gym to the group who had not, I was surprised to find that the gym tanner is a much harder core tanner. They hit the tanning bed 67 percent more often than other salon tanners and were far more likely to report tanning addiction. Gyms seem to be a great place for tanners to get their fix.</p>
<p>We also found in our sample of tanners that more tanning was associated with more exercise. Now we may be onto why gyms provide tanning beds – people who tan a lot love to workout. </p>
<h2>Undermining public health messaging</h2>
<p>We do not know why tanning and exercise is linked so I can only speculate. Both activities are driven by a desire to look and feel better. Regardless, gyms that provide tanning beds reinforce the idea that tanning is part of a beauty regimen, and perhaps even worse, that tanning is part of a healthy lifestyle. Tanning is part of neither. It will destroy your skin and has the potential to completely destroy your health. For decades <a href="https://www.cdc.gov/cancer/skin/burningtruth/base_tan_not_safe_tan.htm">public health campaigns</a> have attempted to dismantle the popular misconception that tanned skin is a sign of good health. </p>
<p>Tanning is a sign the body is receiving too much cancer-causing ultraviolet radiation. It is a warning sign.</p>
<p>Gyms should not provide tanning beds to patrons. Removing tanning beds from gyms surely won’t stop everybody from tanning, but that is certainly no argument for making them convenient for people at higher than average risk of melanoma. By pairing exercise with tanning beds, gyms undermine public health messaging and contribute to the cancer risk of their patrons. If you are
joining a gym to get healthy, my advice is: pick one that has your back.</p><img src="https://counter.theconversation.com/content/98999/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sherry Pagoto receives funding from the National Institutes of Health.</span></em></p>Many gyms use free tanning beds to lure in new members who are eager to look and feel their best. But this, argues Sherry Pagoto, runs against the health lifestyle premise these gyms are advocating.Sherry Pagoto, Professor of Allied Health Sciences, University of ConnecticutLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/639472016-09-09T04:34:16Z2016-09-09T04:34:16ZOne in five tattoo inks in Australia contain carcinogenic chemicals<figure><img src="https://images.theconversation.com/files/137121/original/image-20160908-16611-opufgy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">But it's unclear what that means for cancer risk.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-324788036/stock-photo-master-tattoo-draws-the-orange-paint-on-the-clients-tattoo-tattoo-artist-holding-a-pink-tattoo-machine-in-black-sterile-gloves-and-working-on-the-professional-blue-mat.html?src=mTgEp9KFLcO7JiRH2LHaDQ-1-0">IvanRiver/Shutterstock</a></span></figcaption></figure><p>A <a href="https://www.nicnas.gov.au/communications/issues/Tattoo-inks">report</a> this week from the Australian government’s National Industrial Chemical’s Notification and Assessment Scheme (<a href="https://www.nicnas.gov.au/">NICNAS</a>) shows what’s in the ink that’s under the skin of more than <a href="http://www.mccrindle.com.au/the-mccrindle-blog/tattoos_in_australia_perceptions-_trends_and_regrets">2 million Australians</a> and about <a href="http://www.ncbi.nlm.nih.gov/pubmed/26211826">100 million Europeans</a>. And it’s not pretty.</p>
<p>The report found 471 different tattoo inks likely to be used in Australia made up of 89 unique chemicals. They interviewed 22 professional tattoo artists and sourced 49 specific tattoo inks likely to be used in Australian tattoo parlours for detailed chemical analysis.</p>
<p>Of the 49 inks NICNAS tested, only four complied with the <a href="https://wcd.coe.int/ViewDoc.jsp?p=&Ref=ResAP(2008)1&Language=lanEnglish&Ver=original&Site=CM&BackColorInternet=DBDCF2&BackColorIntranet=FDC864&BackColorLogged=FDC864&direct=true">European standards</a>. </p>
<p>The major concern was the presence of polycyclic aromatic hydrocarbons (PAHs), a group of chemicals <a href="https://monographs.iarc.fr/ENG/Monographs/vol92/mono92.pdf">known to be carcinogens</a>. PAHs were found in more than one-fifth of the samples tested and in 83% of the black inks tested.</p>
<p>Other non-compliant components include barium, copper, mercury, amines and various colourants.</p>
<p>In some inks, there was a mismatch between the content and the labelling.
One ink was sold and used for tattooing when the container label said it was not intended for this purpose.</p>
<p>Gone are the days of tattoos being seen only on bikies and sailors. Increasing proportions of the population have increasing proportions of the dermal layer of their skin injected with the multi-coloured artworks. There is no sign of demand dropping off.</p>
<p>This is an international challenge for <a href="http://www.ncbi.nlm.nih.gov/pubmed/22469126">regulators</a>. Italy, for instance, <a href="http://www.ncbi.nlm.nih.gov/pubmed/25833645">had an eight-fold increase</a> in the number of tattoo parlours from 2006 to 2015. Like us, they struggle to monitor what the effects might be. </p>
<p>Swiss health authorities <a href="http://www.bag.admin.ch/dokumentation/publikationen/01435/04412/05934/index.html?lang=de&sort=">analysed 416 ink samples</a> and found 39 colourants that were never tested for use in contact with the human body. </p>
<p>Traditional Maori tattoos (<a href="http://www.teara.govt.nz/en/ta-moko-maori-tattooing">moko</a>) are a treasure protected by the <a href="http://archives.govt.nz/exhibitions/treaty">Treaty of Waitangi</a>, so regulation in New Zealand has special challenges.</p>
<p>It’s important to remember that humans have been tattooing their skin <a href="https://www.raci.org.au/flipbook?id=101#page=8">for thousands of years</a> using various methods, some very crude. Outside the risks of infection from unclean injecting equipment, and some <a href="http://www.healthguidance.org/entry/14894/1/Reasons-NOT-to-Get-a-Tattoo.html">serious pre-existing medical conditions</a>, there is little evidence directly linking tattooing to serious illness. </p>
<p>However, a <a href="http://www.ncbi.nlm.nih.gov/pubmed/?term=klugl+i+hiller+k+tattoo">German study</a> found 67% of tattooed people reported complications. Of those, 7% were systemic (affecting more than just the skin around the tattoo) and 6% were persistent. These are mostly superficial skin infections but have included bacterial infections such as <a href="http://www.ucl.ac.uk/%7Ezchabg4/staphylococci.htm">staphlococci</a> and <a href="https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/streptococcal-infection-group-a">streptococci</a>, <a href="http://www.niaid.nih.gov/topics/mycobacteria/pages/default.aspx">mycobacteria</a> and, in some rare cases, blood-borne viruses such as <a href="https://theconversation.com/explainer-the-a-b-c-d-and-e-of-hepatitis-54739">hepatitis B and C</a>. </p>
<p>So what does all this mean? In short, <a href="http://www.ncbi.nlm.nih.gov/pubmed/26211826">no one really knows</a>. Will everyone with ink get cancer? No. But the basics of toxicology tell us that the harm any substance does is influenced by how “poisonous” the substance is, the circumstances and nature of the exposure, and the dose people are exposed to. </p>
<p>Is there a prospect that with more people getting more tattoos, cancers linked to this exposure will occur? Again, we don’t know.</p>
<p>Specific concerns that tattoos might cause or mask skin cancer seem – so far at least – <a href="http://www.ncbi.nlm.nih.gov/pubmed/22469126">unfounded</a>.</p>
<p>It seems timely to establish a study to follow up on those who have tattoos and how they fare compared with those with a “blank canvas”. The simple truth is, we have no idea what, if any, long-term health effects go with having tattoo ink injected into human skin.</p>
<p>Another complexity is the “DIY tattoo”. Controlling the ink administered by paid tattoo artists in identifiable businesses is one issue. Controlling the ink that comes through online shopping and is administered by enthusiastic amateurs at home is quite another.</p>
<p>So, if you already have tattoos, what should you do? Removing them may not help. The NICNAS report says:</p>
<blockquote>
<p>These chemicals can undergo photo degradation under exposure to … solar radiation and lasers.</p>
</blockquote>
<p>This means the chemicals, instead of being trapped under the skin, are released into the body. And it’s unclear what effect this might have. </p>
<p>As tattooing becomes increasingly mainstream, we need to ensure those who are considering getting tattooed are fully informed of the risks. And if they wish to proceed, we need to ensure they can do so as safely as possible. </p>
<p>Stopping the use of unsafe ink and related contaminants is a vital first move. This report from NICNAS is an important step towards us getting this house in order.</p><img src="https://counter.theconversation.com/content/63947/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Terry Slevin is Education and Research Director for Cancer Council Western Australia. He is also Chair of the Cancer Council Australia Occupational and Environmental Cancer Committee. He represents Cancer Council Australia on the Strategic Consultative Committee for The National Industrial Chemical Notification and Assessment Scheme (NICNAS) </span></em></p>Of the 49 inks tested, only four complied with the European standards. Carcinogens were found in more than one-fifth of the samples, and in 83% of the black inks.Terry Slevin, Adjunct Professor, School of Psychology and Speech Pathology, Curtin University; Education and Research Director, Cancer Council WA; Chair, Occupational and Environmental Cancer Committee, Cancer Council AustraliaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/636212016-08-10T16:01:51Z2016-08-10T16:01:51ZDoes burnt food give you cancer?<figure><img src="https://images.theconversation.com/files/133657/original/image-20160810-28149-ijyh3i.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p>If you’re offered a plate of blackened barbecue food this summer, you might think twice about eating it. It’s commonly thought that food that has been burnt could cause cancer. This is in part down to one particular molecule that forms when food is cooked at high temperatures, known as acrylamide. But while the chemical is a known potential toxin and carcinogen in its industrial form, the link between consuming it in food and developing cancer is much less clear.</p>
<p>The reason we even know about acrylamide’s potential dangers are down to a railway tunnel. Nearly 20 years ago, workers were building a tunnel through the Hallandsås ridge on the Bjäre peninsula in southern Sweden. Cows nearby started to show strange symptoms, staggering around and in some cases collapsing and dying. This <a href="http://www.eurofound.europa.eu/observatories/eurwork/articles/skanska-managers-found-guilty-of-work-environment-crime">prompted an investigation</a> that showed that they had been drinking contaminated stream water and that the contamination was from a toxic molecule, acrylamide.</p>
<p>The construction workers had been using its polymer, polyacrylamide, as a crack sealant. This was, in itself, quite safe. But the polymer-forming reaction was incomplete, so some unreacted acrylamide was still present. The workers were tested to see if they also had unsafe levels of acrylamide in their blood, with a second “control” group of people who had no known exposure to industrial acrylamide used as a benchmark. However, it turned out that the control group also had surprisingly high amounts of acrylamide in their blood.</p>
<p>At first it was thought that burgers might be the source. Then high levels of acrylamide were found in potato products such as fried potatoes, as well as in coffee. It <a href="http://pubs.acs.org/doi/abs/10.1021/jf020302f">then became clear</a> that acrylamide formation was associated with carbohydrate-rich foods, rather than protein-rich ones, and with foods that had been heated above 120°C (250°F), that is food that has been fried, roasted or baked. This was a new discovery, but acrylamide must always have been formed in this style of cooking, ever since cooking was invented. </p>
<p><a href="http://www.chm.bris.ac.uk/motm/acrylamide/acrylamideh.htm">Acrylamide is formed</a> in reactions between the natural amino-acid asparagine and some (naturally-occurring) carbohydrates. You don’t find acrylamide in uncooked or boiled food. Dairy, meat or fish products are much less likely to contain acrylamide. It doesn’t matter whether the food is “organic” or not, it’s the type of food that counts. Acrylamide is also formed when smoking tobacco.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/133658/original/image-20160810-18037-1y0bzjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/133658/original/image-20160810-18037-1y0bzjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/133658/original/image-20160810-18037-1y0bzjv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/133658/original/image-20160810-18037-1y0bzjv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/133658/original/image-20160810-18037-1y0bzjv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/133658/original/image-20160810-18037-1y0bzjv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/133658/original/image-20160810-18037-1y0bzjv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Acrylamide is found in cooked carbohydrate-rich food.</span>
<span class="attribution"><span class="source">Shutterstock</span></span>
</figcaption>
</figure>
<p>A “golden rule” <a href="https://www.newscientist.com/article/mg19025483-600-acrylamide-the-food-scare-the-world-forgot/">has been suggested</a>: cook food until it goes yellow, not brown or black. This restricts acrylamide formation, though if you cook at too low a temperature you are less likely to kill off bacteria, so there is more risk of food poisoning.</p>
<p>While scientists have identified the source of acrylamide, they haven’t established that it is definitely a carcinogen in humans when consumed at the levels typically found in cooked food. <a href="http://onlinelibrary.wiley.com/doi/10.1002/ijc.29339/pdf">A 2015 review</a> of available data concluded that “dietary acrylamide is not related to the risk of most common cancers”. Although, it added that a modest association for kidney cancer, and for endometrial and ovarian cancers in people who had never smoked, couldn’t be ruled out.</p>
<h2>Meaty concerns</h2>
<p>Going back to the barbecue, there are other chemicals in meat that could be a concern. These generally fall into <a href="http://www.precisionnutrition.com/all-about-cooking-carcinogens">two classes</a>: polycyclic aromatic hydrocarbons (PAHs – compounds with several hexagonal “benzene rings” fused together) such as naphthalene and benzopyrene; and <a href="http://www.sciencedirect.com/science/article/pii/S0278691598000611">heterocyclic amines</a> (HCAs). The PAHs are formed from meat fat and juices dripping onto flames in cooking, and HCAs are generated, again in cooking, from reactions between molecules including amino-acids and sugars.</p>
<p>Animal testing has shown exposure to high levels of chemicals such as these <a href="http://www.cancer.gov/about-cancer/causes-prevention/risk/diet/cooked-meats-fact-sheet">is linked with cancer</a>, but these are levels of exposure much higher than humans would get from eating meat. <a href="http://www.sciencedirect.com/science/article/pii/S0027510702001690">Some studies</a> do appear to <a href="http://www.ncbi.nlm.nih.gov/pubmed/16357191">have shown that</a> meat that has been burned, fried or barbecued is associated with higher possibilities of certain cancers, but these links are hard to prove for certain.</p>
<p>If you are really concerned, you could reduce exposure risks by cooking in a microwave rather than over naked flames, and turning meat regularly. You could also eat less meat or replace the meat with vegetables when grilling. Of course, your food may not be as tasty, since grilling, baking or toasting produce a lot of molecules that enhance flavour. But if you have a healthy diet with lots of fruit, vegetables and whole grain food, none of which contain acrylamide, things are easier. It is all a question of proportion.</p><img src="https://counter.theconversation.com/content/63621/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Simon Cotton does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Chemicals that form in cooked food have been linked to cancer – but the full picture is more complicated.Simon Cotton, Senior Lecturer in Chemistry, University of BirminghamLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/635532016-08-08T13:57:43Z2016-08-08T13:57:43ZDo mobile phones give you brain cancer?<figure><img src="https://images.theconversation.com/files/133365/original/image-20160808-18046-1dhuvwi.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Time to hang up?</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/dl2_lim.mhtml?src=GxsxhjPHS6pDeLrM-xIreQ-1-19&id=395977894&size=medium_jpg">Shutterstock</a></span></figcaption></figure><p>It is a question any mobile phone user would be keen to have answered – and science does offer some clues. In 2011, for example, the International Agency for Research on Cancer (IARC) classified mobile phone radiation as a <a href="https://monographs.iarc.fr/ENG/Publications/Review2014-Radiation-Fatiha.pdf">possible human carcinogen, group 2B</a>. </p>
<p>The classification was based predominantly on evidence from population studies. A <a href="http://www.ncbi.nlm.nih.gov/pubmed/20483835">study</a> by the European Union-funded INTERPHONE group and <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3834325/">another</a> led by L. Hardell, a Swedish epidemiologist, showed an increased risk (40-170%) of developing glioma, a malignant brain cancer, in people who used a mobile phone for 30 minutes a day over ten years. </p>
<p>The idea of mobile phone radiation increasing the risk of cancer was strengthened by two other studies. The <a href="https://www.emf-portal.org/en/article/24860">Cerenat</a> study, published in 2013, confirmed observations of the INTERPHONE and Hardell studies. And an <a href="http://www.ncbi.nlm.nih.gov/pubmed/25749340">animal study</a> in 2015 showed cell phone radiation enhanced the carcinogenic effects of chemicals.</p>
<p>This evidence indicates that mobile phone radiation might indeed be “possibly carcinogenic” (IARC’s group 2B) or even “probably carcinogenic” (IARC’s group 2A) to humans. </p>
<p>IARC classifies agents as carcinogenic (group 1), probably carcinogenic (group 2A), possibly carcinogenic (group 2B), not classifiable as carcinogen (group 3), probably not carcinogenic (group 4).</p>
<p>However, <a href="http://www.ncbi.nlm.nih.gov/pubmed/22249239">other</a> <a href="https://www.emf-portal.org/en/article/29441">studies</a> show the number of people getting brain cancer has remained unchanged or only slightly increased. This is in spite of the dramatic increase in the number of users of mobile phones over the last ten to twenty years. </p>
<p>And so there is a contradiction between the evidence that shows an increased risk of brain cancer and the studies that show that the rate of brain cancer in populations “saturated” by mobile phones is fairly constant. </p>
<h2>Which view is right?</h2>
<p>Those who believe the case-control studies that indicate a causal link between brain cancer and mobile phone radiation to be correct suggest it is still too early to see the clear increase in brain cancer in the general population. There is, after all, a long latency for this cancer (tens of years) and it’s only during the last ten to 15 years that people have begun to use mobile phones intensively. Before that, they were too expensive. </p>
<p>Those who favour the studies that show no particular increase in brain cancer in populations with dramatically increased phone usage, meanwhile, consider the evidence from the case-control studies to be a statistical “glitch”.</p>
<p>But what if both views are correct? What if mobile phone radiation does not itself cause cancer but long-term exposure increases the risk of developing cancer from other causes?</p>
<p>This hypothesis may explain the apparent discrepancy.</p>
<p>Animal studies, evaluated by IARC experts in 2011, suggest that mobile phone radiation alone does not cause cancer. However, it may still have “co-carcinogen” properties. <a href="http://monographs.iarc.fr/ENG/Monographs/vol102/mono102-003.pdf">In five studies</a>, mobile phone radiation increased development of cancer in animals simultaneously exposed to low doses of known chemical carcinogens. One of the five was recently <a href="http://www.ncbi.nlm.nih.gov/pubmed/25749340">replicated</a> and confirmed the co-carcinogenic effect of mobile phone radiation.</p>
<p>To date there has only been a handful of co-carcinogenicity studies where animals or living cells were simultaneously exposed to chemicals and to mobile phone radiation. This poses a serious problem for proper risk estimation.</p>
<p>Based on the very limited, currently available knowledge, mobile phone radiation might not cause cancer itself. Instead, it might activate regulatory processes and accelerate development of the disease.</p>
<p>Using this hypothesis, it is possible to explain several of the “inexplicable” contradictory scientific results.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/133366/original/image-20160808-18030-1he13xg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/133366/original/image-20160808-18030-1he13xg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/133366/original/image-20160808-18030-1he13xg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/133366/original/image-20160808-18030-1he13xg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/133366/original/image-20160808-18030-1he13xg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/133366/original/image-20160808-18030-1he13xg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/133366/original/image-20160808-18030-1he13xg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Examining the brain.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/dl2_lim.mhtml?src=lbRD1O_Fg7csa5RQ0_wrKg-1-2&id=118491940&size=medium_jpg">Shutterstock</a></span>
</figcaption>
</figure>
<p>First, it could be that case-control studies show increased risk of brain cancer not because mobile phone radiation causes it, but because it accelerates the development of brain cancers caused by other carcinogens or which occur due to spontaneous gene mutations.</p>
<p>Second, the incidence of brain cancer is low compared with the high rate of mobile phone use because the increases are solely due to co-carcinogenic effects of mobile phone radiation. Not all users are in danger of developing brain cancer, only those who are developing it as a result of other carcinogenic or genetic factors. </p>
<p>Finally, published in May 2016 <a href="http://biorxiv.org/content/early/2016/06/23/055699">first results</a> from the animal study conducted at the US National Toxicology Program showed a lack of brain cancer in the control group and a very small number of brain cancer cases among the exposed rats. </p>
<p>Animals were exposed solely to mobile phone radiation and because of the small number of brain cancers caused by mobile phone radiation, some questioned the significance of this observation. But the above proposed hypothesis explains this result. Exposed animals developed a small number of brain cancers not because of the mobile phone radiation alone but because it accelerated the development of cancers caused by spontaneous mutations. In the control group, the same brain cancers, caused by spontaneous mutations, had no time to develop because there was no extra stimulus to accelerate them.</p>
<h2>Risk of brain cancer remains low</h2>
<p>Assuming the hypothesis is correct, mobile phone radiation would have less severe implications for public health than suggested by some epidemiological studies. Not all mobile phone users would be in danger of developing brain cancer. Only those exposed to carcinogenic factors or who develop spontaneous gene mutation would be at risk of the development and manifestation of the cancer.</p>
<p>The proposed hypothesis does not invalidate the IARC classification of mobile phone radiation as a possible carcinogen. IARC classification informs only that avid users have an increased risk of developing cancer. It does not say whether radiation is a “carcinogen” or a “co-carcinogen”.</p>
<p>So this hypothesis does not give mobile phone radiation a clean bill of health. It suggests, however, that it might be unlikely that there will be an epidemic of brain cancer but only a modest increase in prevalence.</p><img src="https://counter.theconversation.com/content/63553/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dariusz Leszczynski is a Chief Editor of ‘Radiation and Health’, specialty of Frontiers in Public Health, Lausanne, Switzerland.
Former member of the Working Group of the International Agency for Research on Cancer that in 2011 classified cell phone radiation as a possible carcinogen.
He receives occasionally conference travel funding from Pandora Foundation and Competence Initiative, Germany, Cellraid, Finland, Telstra, Australia, Swinburne University of Technology, Australia or from conference organizers.</span></em></p>The evidence appears contradictory – but there may be a good reason for this.Dariusz Leszczynski, Adjunct Professor of Biochemistry, University of HelsinkiLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/577222016-07-03T20:06:58Z2016-07-03T20:06:58ZPollution guidelines leave a blind spot for assessing the impact of coal and oil<p><a href="http://www.couriermail.com.au/news/queensland/environmentalists-hope-latest-challenge-to-approval-of-adani-mine-will-sto-project/news-story/d87b6b13d670ac4b4e6d15137b814f1a">Coal’s impact on the Great Barrier Reef</a> by causing climate change is one of the reasons why environmentalists oppose the development of coal fields and exports in Queensland. But fossil fuels could have a more direct impact on the reef and the waters around it, through chemicals produced during their production and distribution. </p>
<p>When coal dust is released in the marine environment it can <a href="https://www.crcpress.com/Oceanography-and-Marine-Biology-An-Annual-Review-Volume-43/Gibson-Atkinson-Gordon/9780849335976#googlePreviewContainer">damage marine ecosystems</a>. Coal contains a number of different chemicals, but it is <a href="http://www.atsdr.cdc.gov/csem/csem.asp?csem=13&po=11">polynuclear aromatic hydrocarbons</a> (PAHs), which are known carcinogens, that are of most concern. </p>
<p>Some components of coal PAHs cause biochemical changes in fish and can <a href="http://www.sciencedirect.com/science/article/pii/S0048969714010134">lead to cancer</a>. The coal dust has a very slow degradation rate and will <a href="http://www.sciencedirect.com/science/article/pii/S0272771411001132">build up in the ecosystem from the continuous input</a>.</p>
<p>Coal dust also absorbs chemicals in the coastal zone and transports things like pesticides and herbicides offshore. Oil spills are another source of PAHs in the marine environment. </p>
<p>It is currently impossible for Australia to assess the impact of these chemicals in marine sediments, because our sediment guidelines are out of date. They need to be updated to match the standards used elsewhere, such as in the United States. </p>
<h2>Coal dust and Great Barrier Reef marine life</h2>
<p>I have previously looked at how far these chemicals can travel from coal ports. I found they can be <a href="http://www.sciencedirect.com/science/article/pii/S0272771411001132">detected in suspended sediments</a> all the way to the shelf break <a href="http://www.sciencedirect.com/science/article/pii/S0272771414000894">200km offshore</a>. (I also published a <a href="http://www.sciencedirect.com/science/article/pii/S0272771414002418">corrigendum</a> to this paper to correct data errors and to explain how sediment guidelines need to be updated.)</p>
<p>I used the <a href="http://www.amazon.com/Sediment-Quality-Assessment-Practical-%20Guide/dp/%201486303846/ref=sr_1_fkmr0_2?s=books&ie=UTF8&qid=1457420456&sr=1-2-fkmr0&keywords=Batley%2C+Graeme%2C+and+Stuart+Simpson+%28eds%29.+2016.+Sediment+Quality+Assessment">Australian</a> and the <a href="https://clu-in.org/conf/tio/porewater1/resources/EPA-ESB-Procedures-Determine-freely-dissolved-organics-2012.pdf">US Environment Protection Authority (EPA)</a> sediment quality guidelines to assess the concentration of PAHs in the sediments and suspended sediments on the Great Barrier Reef. The guidelines are meant to indicate “trigger values” for the concentration of possible toxins. If trigger values are reached then sources should be curtailed. </p>
<p>My study showed the concentrations were below toxic levels as then defined by the US guidelines. But it is impossible to know based on the Australian guidelines because these guidelines don’t target the PAHs contained in coal or oil. To explain why, we have to go into a bit of chemistry. </p>
<p>The composition of the PAHs can indicate the source from coal, oil or combustion processes.</p>
<p>The US guidelines use <a href="http://www.tandfonline.com/doi/abs/10.1080/713848389">34 key PAH groups</a> (a total of about 290 individual compounds) and are currently the best available for assessing oil pollution incidents.</p>
<p>The Australian guidelines do not assess the PAHs that are the major contributor to PAHs in coal and oil. The Australian guidelines specify only 20 “parent” PAHs. These guidelines are more relevant to combustion products. </p>
<h2>When is it toxic?</h2>
<p>The Australian guidelines consider PAHs reach toxic levels at <a href="http://www.amazon.com/Sediment-Quality-Assessment-Practical-%20Guide/dp/%201486303846/ref=sr_1_fkmr0_2?s=books&ie=UTF8&qid=1457420456&sr=1-2-fkmr0&keywords=Batley%2C+Graeme%2C+and+Stuart+Simpson+%28eds%29.+2016.+Sediment+Quality+Assessment">10-50 milligrams per kilogram of sediment</a>. But research suggests this is way too high.</p>
<p>Modern assessments of oil spills now rely on the PAH content of oils in <a href="http://pubs.acs.org/toc/esthag/50/2">addition to the total oil content</a>.</p>
<p>PAHs make up about <a href="http://www.sciencedirect.com/science/article/pii/S0272771484710274">1% of total oil content</a>. If you applied these guidelines to an oil spill, the toxic level of 10mg PAH per kg of sediment would equal 1,000mg of oil per kg. This oil content would kill everything in marine sediments. </p>
<p>For example, I and a colleague published a detailed study of <a href="http://science.sciencemag.org/content/197/4302/484">fiddler crabs after the West Falmouth oil spill</a>. We determined that total oil concentrations of 100-200mg oil per kg of sediment were toxic to juvenile crabs. Concentrations of 1,000mg per kg were toxic to adults and/or caused a number of impacts before the crabs died. </p>
<p>As PAHs make up around 1% of most oils, this means that the trigger values should be 1mg PAH per kg (with a maximum of 5mg per kg). And this assessment must include the PAHs that are commonly found in oil and coal.</p>
<p>Commercial Australian labs don’t assess all these PAHs yet, but neither did the American labs until it became necessary for assessing major oil spills such as the <a href="http://www.uscg.mil/history/webshipwrecks/ExxonValdezNRT1989Report.pdf">Exxon Valdez</a> spill in Alaska and the <a href="https://theconversation.com/au/topics/deepwater-horizon">Deepwater Horizon</a> spill in the Gulf of Mexico. We should not wait for the next disaster to upgrade our capability.</p>
<h2>Cleaning up coal ports</h2>
<p>We also need the ports to reduce their inputs. Townsville port has reduced the dust emission from its powdered zinc and lead loadings. </p>
<p>The train cars are covered and one at a time enter a shed which is under negative pressure. The powder is dumped in a hopper, transported to the conveyors and loaded onto the ships with no or little dust escaping the process. </p>
<p>The cars are then rinsed before leaving the shed. Water is retained and filtered so no dust leaves the area. </p>
<p>Why can’t coal be handled the same way? Improvement in loading metal powders was brought on by public objections to the previous operations. </p>
<p>This would eliminate coal piles in the coastal zone which blow dust all over nearby cities such as Gladstone and leach into coastal creeks. We also need the Australian sediment quality guidelines for PAHs brought up to 21st-century standard.</p>
<p>Do we have to wait until we have another incident like the <a href="http://www.abc.net.au/news/2009-08-24/wa-oil-spill-one-of-australias-worst/1402204">Montara platform explosion</a> in the Timor Sea in 2010 before we update our guidelines and response times?</p><img src="https://counter.theconversation.com/content/57722/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kathryn Burns received funding from the Australian Institute of Marine Science for chemistry studies in the Great Barrier Reef lagoon 2008-2010, and retired in 2011.</span></em></p>Coal dust and oil can spread toxic chemicals hundreds of kilometres out to sea. But Australia’s monitoring guidelines do not meet the standards used in countries such as the United States.Kathryn Burns, Marine Scientist, James Cook UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/498392015-10-29T15:54:54Z2015-10-29T15:54:54ZTen deadly carcinogens (you’ve probably never heard of)<figure><img src="https://images.theconversation.com/files/100161/original/image-20151029-15358-58d5ld.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">There are scores of carcinogens. Most aren't as tasty</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/thecssdiv/6726292063/in/photolist-bfo1hP-itDkqe-n2kZP-eSaBv2-5FhXXG-9dKYe5-78QgCz-bnDhLS-qPPUT9-dvHL5r-dnW6pt-5P8uTV-7CKnq8-4RcJAu-oNd9J-5RwNdB-rZUQ7T-6raADB-eed6Ug-7FUoNC-aNjSXv-aMdtiR-agh7XK-aCe2Ez-sxCQN3-5RezZR-ocM7ah-fJ8wk1-fHQWXi-fJ8vb1-bMRqBB-6Z7pga-fDhaYM-mSiwUA-fJqdgN-4EkaKh-oiw4Ro-eevhLS-5J6cGH-mSiu5N-fdX6vP-6uwLS1-57BjB1-fp1ikJ-iGAxix-frU3xd-51myQ7-9J6U5N-8ke7F3-8a8iUG">Ross Bruniges/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>Bad news for bacon butty lovers and barbecue afficionados. The World Health Organisation now deems bacon, sausage – and other processed meats – <a href="http://www.who.int/phe/news/events/international_conference/meeting_report.pdf">a serious cancer risk</a>.</p>
<p>With more than 14m new cancer cases occurring around the world <a href="http://globocan.iarc.fr/Pages/fact_sheets_cancer.aspx">each year</a> and more than 8m cancer deaths a year, carcinogens certainly merit serious attention. Asbestos, diesel exhaust fumes, radiation in various forms, nightshift work, tobacco and alcohol are all well-known causes of cancer, but there are lots more besides, including several you may never have heard of.</p>
<p>Many factors determine the number, type and impact of the carcinogens you may face. You’re sure to be exposed to several. Some people may be exposed to high levels of them, although the greatest public health threat may come from large numbers of people being exposed to low levels of a carcinogen rather than small numbers being exposed to high levels of them. Be aware, however, that even exceptionally low doses of some carcinogens can have a serious effect. </p>
<h2>What’s your risk?</h2>
<p>An individual’s exposure to widely-used carcinogens depends on a wide range of factors: where they live, for example, and for how long, their work, their life circumstances, even what their parents were exposed to in the past. Usually the most vulnerable, the poorest and those in the worst jobs face the greatest risks from “environmental” carcinogens.</p>
<p><a href="http://hwww.iarc.fr">The International Agency for Research on Cancer</a> is the best global scientific source of information on what is and is not a carcinogen, but governments are not required to act on the information they produce. </p>
<p>It is important to remember that not everything is a carcinogen, but here are ten proven Class 1 global human carcinogens that may have passed under your radar.</p>
<p><strong>Biological agents</strong></p>
<p>Biological agents including opisthorchis viverrini , hepatitis B and C and various types of human papillomavirus are a major cause of cancer. <a href="http://monographs.iarc.fr/ENG/Monographs/vol100B/mono100B.pdf">Infectious diseases</a> are estimated to cause well more than 20% of cancers in developing countries and 6% in developed ones. In France, it is estimated that 15% of the workforce, 2.6m workers, are exposed to biological agents.</p>
<p><strong>Trichloroethylene</strong></p>
<p><a href="http://www3.epa.gov/airtoxics/hlthef/tri-ethy.html">Trichloroethylene</a> , an industrial solvent also used in consumer products and commercial degreasing, was once widely used as an anaesthetic and now may also appear in contaminated groundwater across the world. It causes kidney <a href="http://monographs.iarc.fr/ENG/Monographs/vol106/mono106-001.pdf">cancer</a> and there are associations with Non-Hodgkin lymphoma and liver cancer.</p>
<p><strong>Silica dust</strong></p>
<p>Silica dust, crystalline, in the form of quartz or <a href="https://www.osha.gov/OshDoc/data_General_Facts/crystalline-factsheet.pdf">cristobalite</a>, is widely-used in the construction foundry, tunnelling and stone-cutting work. It causes lung cancer. WHO and others have estimated that occupational lung carcinogens – such as silica – account for at least 10% of all lung cancer deaths worldwide. Up to 30% of all male and up to 20% of all female workers have been exposed at work to lung carcinogens. </p>
<p><strong>Shale oils</strong></p>
<p><a href="http://monographs.iarc.fr/ENG/Monographs/vol100F/mono100F-20.pdf">Shale oils</a> are mined and when processed may also present a range of risks as a fuel oil. Skin cancer in process workers was reported more than 100 years ago. Now shale oil extraction may involve exposure to a range of natural and man-made carcinogens. </p>
<p><strong>Radon gas</strong></p>
<p>Naturally-occurring <a href="http://monographs.iarc.fr/ENG/Monographs/vol43/">radon gas</a> causes lung cancer. It is estimated that residential radon could cause up to 14% of all lung cancers, the second highest cause of lung cancer. However, radon gas at dangerous levels may also be present in shops, offices and factories unless there is effective ventilation and sealing floors and walls. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/100162/original/image-20151029-15348-vrlzng.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/100162/original/image-20151029-15348-vrlzng.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/100162/original/image-20151029-15348-vrlzng.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/100162/original/image-20151029-15348-vrlzng.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/100162/original/image-20151029-15348-vrlzng.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/100162/original/image-20151029-15348-vrlzng.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/100162/original/image-20151029-15348-vrlzng.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Watch out! There could be benzene in that.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/coolinsights/5127279893/in/photolist-8P5DFt-7UGqzz-a2H49A-85suS7-v82tZ6-7ZNMSm-bWXkjG-99Ra4S-99N15c-7JB9Mc-9TrG6R-7TTKZp-81kmGX-8gLyR8-buvSZX-7UKG8S-7Z3CWB-nkKZb8-9GFL3p-9GJBdU-5hV2d1-fZpjyY-9Tuw2y-a8yaJs-9TrFd2-g81BS-9Tuwgu-7THLSk-4uRVTC-bXkwLB-9QWshP-tpjonG-9gs5hK-9c3qZz-7V6gMf-sfzUAu-7TM29h-7Pkt1v-62ZbSo-4DZxot-7Z6yMC-ojToEr-6yrdq2-uK7N98-qfGP9X-7Z6yK1-shT4XD-a8vsKM-a8vdZ2-a8vdhD">Walter Lim/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p><strong>Benzene</strong></p>
<p><a href="http://www.cancer.gov/about-cancer/causes-prevention/risk/substances/benzene">Benzene</a> is used as a solvent in the chemical and pharmaceutical industry and occurs in petrol, vehicle exhaust fumes, glues and adhesive products. It causes leukaemia and at least 2% of leukaemia cases worldwide are attributable to occupational exposures. There are natural sources of benzene, too, from volcanoes, forest fires and as a natural part of crude oil, gasoline and cigarette smoke. The oil and gas industry may produce benzene during processing and it may pollute water supplies. </p>
<p><strong>Aristolochic acid</strong></p>
<p><a href="https://ntp.niehs.nih.gov/ntp/roc/content/profiles/aristolochicacids.pdf">Aristolochic acid</a> is found in the Birthwort plant and was long used in Chinese herbal medicine as well as being cultivated as an ornamental plant. It is also produced as a research chemical and may possibly have contaminated wheat fields in China. It causes upper urinary tract cancers.</p>
<p><strong>Chromium VI</strong></p>
<p><a href="http://monographs.iarc.fr/ENG/Monographs/vol100C/mono100C-9.pdf">Chromium (VI)</a> occurs naturally but when processed as compounds it is used in textile dyes, paints, inks and plastics as well as for tanning and metal finishing. It can enter air, water and soil. It causes [lung, nasal and sinus cancers]( (http://www.atsdr.cdc.gov/csem/csem.asp?csem=10&po=7). Several million workers worldwide are estimated to be exposed to chromium compounds.</p>
<p><strong>Beryllium</strong></p>
<p><a href="http://www.ccohs.ca/oshanswers/diseases/beryllium.html">Beryllium</a> occurs naturally and is mined for use in alloys, nuclear reactors and in micro-electronics. In the past, it was used in fluorescent lighting and radio valves – where occasional low level exposures could occur for those people repairing old equipment – as well as in dental prosthetics. Beryllium compounds are linked with lung cancers.</p>
<p><strong>Sulphuric acid mists</strong></p>
<p><a href="http://monographs.iarc.fr/ENG/Monographs/vol100F/mono100F-33.pdf">Sulphuric acid mists</a> are used in making fertilisers, in food manufacturing, batteries, copper smelting and pickling. In Europe alone, 700,000 workers are exposed to these mists which can cause cancer of the larynx – and there’s also evidence that they can cause lung cancer.</p>
<p>So eat, drink and be merry and then put pressure on government and industry to cut hazardous exposures of the public to as many human carcinogens as possible. They really can affect us all.</p><img src="https://counter.theconversation.com/content/49839/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Watterson does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>WHO has said that processed meats cause cancer. But there are more, less visible carcinogens to worry aboutAndrew Watterson, Chair in Health Effectiveness, University of StirlingLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/495422015-10-26T06:04:46Z2015-10-26T06:04:46ZDoes fracking cause cancer and infertility?<p>It can be hard to know what to believe when it comes to fracking safety. Campaigners against the controversial oil and gas drilling technique say it can <a href="http://www.theguardian.com/environment/2014/jan/06/drilling-pollution-complaints-state-reports-pennsylvania">contaminate water</a> supplies, pollute local air and cause <a href="http://www.theguardian.com/environment/2015/aug/26/fracking-earthquakes-waste-disposal-potential-lawsuit-epa">dangerous earthquakes</a>. But the fossil fuel industry contradicts these claims by pointing <a href="https://royalsociety.org/topics-policy/projects/shale-gas-extraction/report/">to reports</a> that the risks can be managed and fracking operations set up safely. </p>
<p>Both sides have also been accused of misrepresenting the evidence. In 2013, the Advertising Standards Agency (ASA) <a href="https://www.asa.org.uk/Rulings/Adjudications/2013/4/Cuadrilla-Resources-Ltd/SHP_ADJ_203806.aspx#.VierSNY-DuQ">ruled that</a> the fracking firm Cuadrilla Resources had published misleading information exaggerating the strength of the evidence for the technique’s safety. More recently, the same company complained to the ASA that the charity Friends of the Earth <a href="http://www.bbc.co.uk/news/uk-england-lancashire-34570974">stated in an advert</a> that chemicals used in fracking could cause cancer. Cuadrilla said only chemicals deemed non-hazardous to groundwater would be used in any UK fracking operations.</p>
<p>No doubt this won’t be the last controversy about the hazards of fracking but it reminds us that there is a significant public health issue at stake here. In the US, almost <a href="http://www2.epa.gov/sites/production/files/2015-03/documents/fracfocus_analysis_report_and_appendices_final_032015_508_0.pdf">700 different chemicals</a> have been used in fracking, some of which have been linked not just to cancer but <a href="http://ehp.niehs.nih.gov/1409535/">also reproductive issues</a>.</p>
<p>What’s more, some of these health problems have been directly linked with fracking operations. For example, <a href="http://pdfs.journals.lww.com/epidem/9000/00000/Unconventional_Natural_Gas_Development_and_Birth.99128.pdf">one strong study</a> of more than 10,000 babies born near fracking operations in Pennsylvania from 2009 to 2013 found that the 25% of mothers most exposed to fracking were 40% more likely to give birth prematurely than the 25% least exposed.</p>
<p>There are a number of papers looking at the potential for fracking to cause cancer in humans but as development of the disease takes years there are not yet any studies proving whether there is a connection or not.</p>
<h2>Unknown in the UK</h2>
<p>The problem is that there hasn’t been any large scale commercial fracking in other countries, and we do not yet know exactly which chemicals will be used if and when operations start. We also don’t know how fracking workers and local communities might be exposed to these chemicals in the short, medium and long term. Another problem is that chemicals that might appear harmless on their own could interact with other natural substances in the rock being fracked.</p>
<p>All this means we can’t say for sure how much of a risk new fracking operations outside of the US will pose to people living nearby. That’s why researchers are looking so closely at US studies analysing fracking substances used there and the exposures linked to fracking and the areas where it has been carried out. </p>
<p>We have a definitive source of information on cancer-causing substances in the WHO’s <a href="http://www.iarc.fr/">International Agency for Research on Cancer</a>. This carries out research to identify proven human carcinogens (Class 1) as well as probable (2A) and possible (2B) ones. Class 1 human carcinogens in the IARC list that have been linked with fracking in the US or recorded near fracked wells include benzene, formaldehyde, crystalline silica dust in the form of quartz or cristobalite, and diesel engine exhaust.</p>
<p>Industries also often argue that even if people were exposed to these chemicals, it would not be enough to threaten their health. They also argue that the public is much more likely to be exposed to other sources of these chemicals from wider pollution, transport and food and drink consumption. Communities in areas likely to be fracked or affected by other forms of unconventional gas extraction <a href="http://www.refracktion.com/index.php/myth-busting/myth-3-fracking-fluids-are-harmless/">appear unconvinced</a> by such arguments.</p>
<h2>Complex mixture</h2>
<p>One of the issues is that it’s not possible to say for sure what will happen to the chemicals once they are injected into the ground. <a href="http://pubs.acs.org/doi/abs/10.1021/es503724k">One study</a> looked at chemicals used in the US called biocides, which prevent clogging in the fracking process. On their own, some of these <a href="http://source.colostate.edu/csu-review-environmental-impact-toxicity-biocides-used-fracking-still-largely-unknown/">are reportedly</a> toxic and carcinogenic. But the authors also identified gaps in industry knowledge about what happened when the biocides mixed with plastic gelling agents, friction reducers and groundwater pollution.</p>
<p>They found the biocides sometimes degraded into carcinogenic formaldehyde and nitrosamines, and that some biocides could react with water to become more toxic and persistent. And they noted there had been 595 documented spills from fracked wells in 2013 in Colorado alone, giving some sense of the scale of the industry’s challenge to prevent pollution.</p>
<p>This lack of information may not be resolved even after fracking operations begin. Fracking companies in the UK say they will fully disclose the details of any chemicals they use. But there is still <a href="http://www.theguardian.com/environment/2013/feb/28/shale-gas-lobbyist-urges-disclose-chemicals">no legal requirement</a> to reveal this information to the public and, so far, firms have only agreed in principle to disclose to the Environment Agency. As such, the controversy and conflict over fracking and its health impact looks set to continue for some time.</p><img src="https://counter.theconversation.com/content/49542/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Andrew Watterson is not currently a member of any political party, industry association or environmental or community group and takes no funding or consulting monies or any other moniesfrom either the industry or its critics</span></em></p>Fracking in the US has relied on chemicals linked to a range of health problems but the industry claims UK operations would be far safer.Andrew Watterson, Chair in Health Effectiveness, University of StirlingLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/480152015-09-23T06:37:16Z2015-09-23T06:37:16ZDiesel fumes and your health: VW cover-up shows we need to test local cars<p>Volkswagen <a href="https://theconversation.com/how-volkswagen-got-caught-cheating-emissions-tests-by-a-clean-air-ngo-47951">has been</a> systematically fixing its diesel cars to be clean during vehicle testing in the United States and then pollute more heavily when on the road. This allowed its vehicles to pass rigorous emissions tests, giving customers maximum driving performance at the cost of the environment and our health.</p>
<p>Diesel exhaust fumes are a <a href="http://www.iarc.fr/en/media-centre/pr/2012/pdfs/pr213_E.pdf">group one carcinogen</a>, meaning they can cause cancer in humans. So covering them up is a serious offence. In the US, this can result in fines of up to $US18 billion.</p>
<p>It’s unclear whether the cheating has occurred in Australia, but Volkswagen’s head said 11 million cars could be affected worldwide including popular models such as the Golf and Beetle, which are popular in Australia. </p>
<p>There’s also the potential that other manufacturers have been using the same dirty trick, and there are Australian firms that blatantly <a href="https://web.archive.org/web/20150402104909/http://www.chiptuning.com.au/dpf-removal-service/">advertise</a> removing anti-pollution devices in order to improve performance.</p>
<p>Levels of air pollution are mostly controlled by government policy, so government action is what’s needed here. </p>
<h2>Health harms</h2>
<p>Diesel exhaust fumes are a known cause of lung cancer and may cause bladder cancer. Burning diesel creates large amounts of particulate matter air pollution including small particles of less 2.5 micrometers (known as PM2.5). </p>
<p>The Clean Air Scientific Advisory Committee, set up by the US Environmental Protection Agency (EPA, which is <a href="http://www3.epa.gov/otaq/cert/documents/vw-nov-caa-09-18-15.pdf">leading the investigation</a> into VW), concluded that short- and long-term exposure to PM2.5 could cause death and cardiovascular harm (by increasing the risk of strokes and heart attacks) and was likely to cause respiratory harms such as asthma. </p>
<p>Similarly the World Health Organization has <a href="http://www.who.int/mediacentre/factsheets/fs313/en/">stated that</a>:</p>
<blockquote>
<p>there is a close, quantitative relationship between exposure to high concentrations of small particulates and increased mortality or morbidity.</p>
</blockquote>
<p>Diesel exhausts also pollute the air with nitrogen oxides (NOx), and this is a known cause of respiratory and cardiovascular disease. The on-road VW tests in the US found that NOx pollution levels were 15 to 35 times higher than the legal limit. </p>
<p>With so many cars creating so much more pollution there will have been health effects. It’s hard to say exactly how many more hospitalisations and deaths without more data, but the US EPA may attempt to quantify this as part of any legal case.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/95791/original/image-20150923-25748-19tqal8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/95791/original/image-20150923-25748-19tqal8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/95791/original/image-20150923-25748-19tqal8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/95791/original/image-20150923-25748-19tqal8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/95791/original/image-20150923-25748-19tqal8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=501&fit=crop&dpr=1 754w, https://images.theconversation.com/files/95791/original/image-20150923-25748-19tqal8.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=501&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/95791/original/image-20150923-25748-19tqal8.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=501&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Urban Australians’ main exposure to poor quality air is due to traffic pollution.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/jefah/2662924303/in/photolist-54jbBZ-oi7XVU-o3FgAR-o3DE3v-cfDumE-ojWYqN-ok9Fgz-o3EjyN-3hxA2h-77syy3-ojWT2b-p9vSXj-o3DR9j-ddTo9c-9vuPur-ok7Emu-o3Fjiz-ojS7YX-o3DYn7-omURpe-5XFTbX-au8WiH-oDEdXm-7GmWQN-o3Eu7B-ok7JUY-oi7VgL-ojXfw5-o3E4zw-omURGP-ojXwE7-o3EiqX-omUU66-ojXffd-b3JXAt-o3EbKS-ojSefe-o3Ey67-o3Eq3y-ok9MJe-o3DVcE-aTbjck-5w3jht-ojXvDE-ok83ZA-pYuWA8-ojXuxG-ewaUYP-6KNm8u-faMP6G">Jeff Hills/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<h2>Random testing</h2>
<p>There are a range of options Australian governments could take to reduce the harm of diesel exhaust fumes. </p>
<p>First, it seems prudent to see whether there’s a problem in Australia with new vehicles rorting pollution controls. This could be achieved by random on-road testing. A bit like random breath testing of drivers, this would tests the car’s fitness to drive. </p>
<p>Random tests would inconvenience a small number of people and testing two to three hundred diesel vehicles would make it clear if there was a big problem. It would be relatively low cost, but would need technical experts as well as the help of the police.</p>
<p>Next, we could introduce more systematic testing, such as adding a vehicle emission test to the roadworthy certificate needed to sell a car. </p>
<p>Alternatively, all in-use vehicles could be subject to an annual or bi-annual test of vehicle emissions by state transport departments. This already happens in <a href="https://www.dmv.ca.gov/portal/dmv/?1dmy&urile=wcm:path:/dmv_content_en/dmv/vr/smogfaq#BM2535">California</a> and the <a href="https://www.gov.uk/emissions-testing">United Kingdom</a> and if a vehicle fails the test it can’t be driven or sold. </p>
<p>This is a higher cost option but would likely provide better compliance across the vehicle fleet than random testing. Australia does have <a href="http://www.legislation.vic.gov.au/Domino/Web_Notes/LDMS/PubStatbook.nsf/b05145073fa2a882ca256da4001bc4e7/34858C99A54B5E99CA257C3D0019F70D/$FILE/13-159sra%20authorised.pdf">emissions standards for in-use cars</a>, but they are not enforced to the same extent as those overseas. Testing here could be targeted towards those vehicles that cause the greatest harm, and the obvious target is diesel vehicles in urban areas.</p>
<h2>Diesel vehicles</h2>
<p>Diesel emissions have improved markedly in recent years, and diesel has a green image because of the better mileage, but their air pollution scorecard is still worse than the typical petrol vehicles. This is probably why VW fixed its diesel emission levels. </p>
<p>Diesel cars and trucks produce more nitrogen oxides and particulate matter pollution, which are particularly damaging to health.</p>
<p>Our <a href="http://www.ncbi.nlm.nih.gov/pubmed/24552771">previous research showed</a> that when the price of diesel fell in Brisbane there was an increase in air pollution across the city likely driven by increased use, whereas there was no increase in air pollution for cheaper petrol. </p>
<p>Ideally, there would be no diesel vehicles in urban areas except for people who truly needed them for work. The mayors of <a href="http://www.theguardian.com/world/2014/dec/07/paris-mayor-hidalgo-plans-ban-diesel-cars-french-capital-2020">Paris</a> and <a href="http://www.theguardian.com/environment/2014/jul/29/increase-diesel-taxes-fight-pollution-boris-johnson-green-groups-fuel">London</a> have both expressed a desire to rid their cities of diesel vehicles. </p>
<p>The main source of exposure to poor quality air for many city-dwelling Australians is traffic pollution. Cleaning the air by increasing the number of cleaner vehicles has the potential to greatly improve health, including reducing asthma admissions to hospital, reducing strokes and even deaths. Norway, for instance, has <a href="https://en.wikipedia.org/wiki/Plug-in_electric_vehicles_in_Norway#Government_incentives">dramatically increased</a> the number of clean electric vehicles by lowering taxes and providing free parking and road tolls.</p>
<p>Having more dirty diesel vehicles on the road is about the worst thing that could happen in Australian cities. VW has a lot of questions to answer.</p><img src="https://counter.theconversation.com/content/48015/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Volkswagen’s cheating allowed its vehicles to pass rigorous emissions testing, giving customers maximum driving performance at the cost of the environment and our health.Adrian Barnett, Associate Professor of Public Health, Queensland University of TechnologyLuke Knibbs, Senior Lecturer, School of Public Health, Faculty of Medicine and Biomedical Sciences, The University of QueenslandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/437842015-07-02T04:55:50Z2015-07-02T04:55:50ZExplainer: do common chemicals increase your risk of cancer?<figure><img src="https://images.theconversation.com/files/87101/original/image-20150702-10590-8jrijh.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">No, we're not swimming around in a soup of cancer-causing chemicals</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/fhmira/2955984656/in/photolist-5vdcfG-fRUVQN-4aS9Ha-6zHuYx-dFaigc-4Qsje-bAaAm-6UAJq-dg4CeB-ih4Vst-832sJ9-e2H9Q4-8jTuAC-5z97DJ-8s5nmy-dqohMW-mJpLj8-iBQAMu-rgcKLF-rdUuLY-4DGTsB-2iSP7C-53LXPN-fXwXBH-8fBxQ7-b33zS6-fmMyRx-9ty3HA-r8qG6U-5J1P8-6hj9d4-dzXP3v-wx45q-6ZoFN3-7U51tQ-DxnvL-2Ymunn-8Neg3C-qAXQZL-7z7ixm-8wsRUf-34Mm9B-CebRM-mJpBbX-qQpcnD-8qP5V-mJrEPq-mJrH8o-mJrvd1-kjUY5p">F Mira/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>New research about the risk of cancer from exposure to common chemicals is usually accompanied by headlines screaming “X causes cancer!” So when a new study on the topic was published in <a href="http://carcin.oxfordjournals.org/content/36/Suppl_1/S254.full">Carcinogenesis</a> last week, I cringed in anticipation.</p>
<p><a href="https://theconversation.com/explainer-what-is-cancer-1673">Cancer</a> is caused by a combination of genetic and environmental influences – a kind of <a href="https://theconversation.com/why-the-causes-of-cancer-are-more-than-just-random-bad-luck-36250">genetic lottery</a> where the odds are stacked by environmental and lifestyle factors.</p>
<p>There are valid concerns over chemical exposure and cancer risk. The World Health Organization (WHO) and International Agency for Research on Cancer (IARC) <a href="http://www.researchgate.net/publication/271833028_Assessing_the_Carcinogenic_Potential_of_Low_Dose_Exposures_to_Chemical_Mixtures_in_the_Environment_The_Challenge_Ahead">estimate</a> toxic environmental exposure to known carcinogens accounts for between 7% and 19% of cancer cases. With around 14 million new cases of cancer diagnosed worldwide annually, this accounts for a huge personal and financial cost.</p>
<p>The reporting of this kind of study is often framed in a way that fuels <a href="http://www.compoundchem.com/2014/05/19/natural-vs-man-made-chemicals-dispelling-misconceptions/">chemophobia</a>, an “irrational” fear of chemicals. It’s perfect fodder for the likes of blogger <a href="http://gawker.com/the-food-babe-blogger-is-full-of-shit-1694902226">Food Babe</a> and the echo chamber of alternative health blogs.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/87071/original/image-20150702-27114-1ibyaoh.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/87071/original/image-20150702-27114-1ibyaoh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/87071/original/image-20150702-27114-1ibyaoh.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=600&fit=crop&dpr=1 600w, https://images.theconversation.com/files/87071/original/image-20150702-27114-1ibyaoh.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=600&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/87071/original/image-20150702-27114-1ibyaoh.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=600&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/87071/original/image-20150702-27114-1ibyaoh.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=754&fit=crop&dpr=1 754w, https://images.theconversation.com/files/87071/original/image-20150702-27114-1ibyaoh.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=754&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/87071/original/image-20150702-27114-1ibyaoh.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=754&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption"><Many natural chemicals are just as harmful to human health, if not more so, than man-made chemicals.</span>
<span class="attribution"><a class="source" href="http://www.compoundchem.com/2014/05/19/natural-vs-man-made-chemicals-dispelling-misconceptions/">Compound Interest</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<p>In this latest case, the <a href="http://www.dailymail.co.uk/news/article-3135384/50-everyday-chemicals-mix-raise-cancer-risk-Substances-fried-potatoes-handwash-suncream-lead-cancer-combined.html">Daily Mail didn’t disappoint</a>, with its headline claiming chemicals in fried potatoes, handwash and sunscreen could lead to cancer if combined. The Daily Mail’s hyperbolic contribution to classifying things as either causing or curing cancer (or both) is legendary, spawning the <a href="http://kill-or-cure.herokuapp.com">Kill or Cure website</a>.</p>
<h2>Everything gives you cancer?</h2>
<p>The IARC <a href="http://monographs.iarc.fr/ENG/Classification/">classifies chemicals</a> on a scale of decreasing carcingogenic certainty. The widely used weedkiller glyphosate, for example, was <a href="http://www.nature.com/news/widely-used-herbicide-linked-to-cancer-1.17181">recently classified</a> in Group 2: possibly/probably carcinogenic to humans. </p>
<p>For context, this places it in the same category as burning wood in your fireplace and shift work. There is a <em>possible</em> link to lymphoma with very high glyphosate exposure (for farmers spraying huge quantities of the stuff) but the data are limited and conflicting.</p>
<p><a href="http://ajcn.nutrition.org/content/97/1/127.long">This review</a> of the cancer risk associated with 50 common ingredients from random recipes in a cookbook is a brilliant demonstration of the difficulties faced in weighing evidence for cancer risk. While lots of studies claim a link between various foods and either increased cancer risk, or a protective effect, in many cases the evidence is unconvincing. </p>
<p>Sensationalist reporting of medical research often leaves a lot to be desired, but the blame doesn’t always lay at the feet of journalists and bloggers. A recent <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0127848">case study</a> of reporting around a study into pancreatic cancer risk and red meat consumption showed that most journalists simply regurgitated information in the accompanying press release.</p>
<h2>Does this study tell us anything new?</h2>
<p>The latest study represents a big effort by an international team of more than 200 cancer biologists and toxicologists involved in the <a href="http://www.gettingtoknowcancer.org">Halifax Project</a>. It is not a primary research study, but reviews the available literature on the carcinogenic potential of low-dose environmental exposure to chemical mixtures. </p>
<p>Data on 85 chemicals – with varying levels of evidence – were included in the review. In some cases, only a single study was available, so the evidence is severely limited in some aspects.</p>
<p>The Halifax Project study puts forward an interesting <em>hypothesis</em> – that exposure to low doses and mixtures of chemicals might synergise to cause cancer. The authors go on to suggest that World Health Organization efforts to assess chemical safety should be realigned with our current understanding of cancer biology.</p>
<p>Probably the most telling (under)statement in the whole paper is that:</p>
<blockquote>
<p><em>[the hypothesis] needs to be rigorously pursued before the merits of this hypothesis can be further advanced</em>. </p>
</blockquote>
<h2>A new framework for understanding chemical risk in cancer?</h2>
<p>For me, the most interesting outcome of this study is the recommendation to change research and regulatory strategy when assessing chemical risk to use an “<a href="http://www.sciencedirect.com/science/article/pii/S0300483X13002308">adverse outcome pathway concept</a>” model.</p>
<p>In other words, the carcinogenic potential of low-dose chemical exposure should be interpreted in the context of the “<a href="http://www.sciencedirect.com/science/article/pii/S0092867411001279">hallmarks of cancer</a>”. This concept provides a mechanistic framework for understanding cancer biology, describing characteristic features of tumours such as sustained growth, new blood vessel formation, and so on.</p>
<h2>Missing the forest for the trees</h2>
<p>The hallmarks concept has been a galvanising force in cancer biology. Its great strength is as an organising principle for rationalising the complexity of cancer. It is only valid as a whole.</p>
<p>To assess the cancer-causing potential of chemical agents against each of the individual hallmarks in isolation completely misses the point. Effects on a single individual feature in isolation do not necessarily translate into transforming a normal cell into a cancer cell. Even then, there are huge challenges in translating lab-based findings on the effects of individual chemicals or mixtures of chemicals to whole body in real world.</p>
<h2>What can we do?</h2>
<p>The authors of this study admit their suggestion for expanding the evaluation of chemical risk is “not a trivial undertaking” and it would be hugely expensive. In the face of limited funding and time, it’s valid to question whether this approach will provide a return on the investment.</p>
<p>Environmental chemical exposure is a valid concern, but the evidence does not support hyperbolic claims that we are swimming around in a soup of cancer-causing chemicals. Lifestyle changes such as giving up smoking, maintaining a healthy weight and avoiding too much alcohol are far more achievable ways to reduce cancer risk.</p><img src="https://counter.theconversation.com/content/43784/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Darren Saunders receives funding from NHMRC</span></em></p>Cancer is caused by a combination of genetic and environmental influences – a kind of genetic lottery where the odds are stacked by environmental and lifestyle factors.Darren Saunders, Senior Lecturer, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/400362015-04-20T05:04:49Z2015-04-20T05:04:49ZThe mystery of breast cancer<p>For most of the common cancers, a major cause has been identified: smoking causes <a href="http://med.stanford.edu/biostatistics/abstract/RobertProctor_paper1.pdf">90% of lung cancer worldwide</a>, hepatitis viruses cause most liver cancer, <em>H pylori</em> bacteria <a href="http://www.ncbi.nlm.nih.gov/pubmed/24889903">causes stomach cancer</a>, Human papillomavirus causes almost all cases of <a href="http://www.cdc.gov/cancer/hpv/statistics/cases.htm">cervical cancer</a>, colon cancer is <a href="http://www.ncbi.nlm.nih.gov/pubmed/22158327">largely explained</a> by physical activity, diet and family history. </p>
<p>But for breast cancer, there is no smoking gun. It is almost unique among the common cancers of the world in that there is not a known major cause; there is no consensus among experts that proof of a major cause has been identified. </p>
<p>Yet, breast cancer is the most common form of cancer in <a href="http://www.who.int/mediacentre/factsheets/fs297/en/">women worldwide</a>. The risk <a href="http://globocan.iarc.fr/Pages/fact_sheets_cancer.aspx">is not equally distributed</a> around the globe, though. Women in North America and Northern Europe have long had five times the risk of women in Africa and Asia, though recently risk has been increasing fast in Africa and Asia for unknown reasons. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/78092/original/image-20150415-31691-dptqsl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/78092/original/image-20150415-31691-dptqsl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=402&fit=crop&dpr=1 600w, https://images.theconversation.com/files/78092/original/image-20150415-31691-dptqsl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=402&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/78092/original/image-20150415-31691-dptqsl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=402&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/78092/original/image-20150415-31691-dptqsl.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=505&fit=crop&dpr=1 754w, https://images.theconversation.com/files/78092/original/image-20150415-31691-dptqsl.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=505&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/78092/original/image-20150415-31691-dptqsl.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=505&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Was it something I ate?</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-2024202/stock-photo-supermarket.html?src=uWWE4rUoHUIzS65Kzhlheg-3-12">Supermarket aisle via www.shutterstock.com.</a></span>
</figcaption>
</figure>
<h2>Is diet to blame?</h2>
<p>Up until about 20 years ago, we thought it was all about diet. As people abandon their local food sources and begin to eat highly processed foods with lots of fats, the hypothesis went, breast cancer was thought to be more likely to develop. </p>
<p>This hypothesis was logical because when researchers analyzed countries’ per capita fat consumption and breast cancer mortality rates, they found a <a href="http://cancerres.aacrjournals.org/content/35/11_Part_2/3374">strong correlation</a>. In addition, rats fed a high-fat diet are more prone to breast tumors. </p>
<p>By studying Japanese migrants to California, researchers found that the first generation had low risk like their parents in Japan, but then by the second and third generation, <a href="http://www.ncbi.nlm.nih.gov/pubmed/7742407">risk was as high</a> as white American women. So, the genetics of race did not account for the stark differences in the breast cancer risk between Asia and America. This was also consistent with the idea that the change in food from the lean Asian diet to the high-fat American diet causes cancer. So it all made sense.</p>
<p>Until it didn’t. </p>
<h2>Diet studies find that fat is not the answer</h2>
<p>Starting in the mid-1980s, large, well-done prospective studies of diet and breast cancer began to be reported, and they were uniformly negative. Fat in the diet of adult women <a href="http://www.ncbi.nlm.nih.gov/pubmed/3785347">had no impact</a> on breast cancer risk at all. </p>
<p>This was very surprising – and very disappointing. The evidence for other aspects of diet, like fruits and vegetables, has been <a href="http://www.ncbi.nlm.nih.gov/pubmed/24330083">mixed</a>, though alcohol consumption does increase risk modestly. It is also clear that heavier women are at higher risk after menopause which might implicate the total amount of calories consumed if not the composition of the diet. </p>
<p>There is a chance that early life dietary fat exposure, even in utero, <a href="http://www.ncbi.nlm.nih.gov/pubmed/9823005">may be important</a>, but it’s difficult to study in humans, so we don’t know much about how it might relate to breast cancer risk later in life. </p>
<p>If diet is not the major cause of breast cancer, then what else about modernization might be the culprit? </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/78094/original/image-20150415-31660-xtlhen.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/78094/original/image-20150415-31660-xtlhen.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/78094/original/image-20150415-31660-xtlhen.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/78094/original/image-20150415-31660-xtlhen.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/78094/original/image-20150415-31660-xtlhen.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/78094/original/image-20150415-31660-xtlhen.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/78094/original/image-20150415-31660-xtlhen.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Some risk factors, like exercise, can be modified.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-175183394/stock-photo-fit-sports-woman-jogging-at-park.html?src=h_0DMjDoxgREWJUukUoIEQ-1-0">Runner via www.shutterstock.com.</a></span>
</figcaption>
</figure>
<h2>Two kinds of risk factors: what we can modify, and what we can’t</h2>
<p>The factors shown to affect a woman’s risk for developing breast cancer fall into <a href="http://www.cancer.org/cancer/breastcancer/detailedguide/breast-cancer-risk-factors">two categories</a>. First, those that cannot be easily modified: age at menarche, age at birth of first child, family history, genes like BRCA1. And second, those that are modifiable: exercise, body weight, alcohol intake, night-work jobs. </p>
<p>The role of environmental pollution is controversial and also <a href="http://www.ncbi.nlm.nih.gov/pubmed/24818537">difficult to study</a>. The concern about chemicals, particularly endocrine disruptors, started after the realization that such chemicals could affect cancer risk in <a href="http://www.niehs.nih.gov/health/topics/agents/endocrine/">rodent models</a>. But in human studies the evidence is mixed.</p>
<p>Because child bearing at a young age and breast feeding reduce risk, the incidence throughout Africa, where birth rates tend to be higher, and where women start their families at younger ages, <a href="http://www.who.int/bulletin/volumes/91/9/13-020913/en/">has been lower</a>. </p>
<p>Death rates, however, from breast cancer in sub-Saharan Africa are now almost as high as in the developed world <a href="http://www.ncbi.nlm.nih.gov/pubmed/24604092">despite the incidence still being much lower</a>. This is because in Africa, women are diagnosed at a later stage of disease and also because there are far fewer treatment options.</p>
<p>The question is whether the known risk factors differ enough between the high-risk modern societies and the low-risk developing societies to account for the large differences in risk. The answer: probably not. Experts think that less than half the high risk in America is explained by the <a href="http://www.ncbi.nlm.nih.gov/pubmed/7473816">known risk factors</a>, and that these factors explain <a href="http://www.ncbi.nlm.nih.gov/pubmed/2228308">very little of the difference</a> in risk with Asia. </p>
<p>A related question is whether the high risk in America and Northern Europe is due to a combination of many known exposures, each of which affects risk a little bit, or mostly due to a major cause that has so far eluded detection. And maybe some of the known risk factors have a common cause which we don’t yet understand. </p>
<h2>Are we just finding more cancer?</h2>
<p>Since the 1980s, screening by mammography has accounted for some of the increase in incidence in the modern world compared to the developing world, but not nearly enough to explain the entire difference. About 20% of the cancers found by mammography are now believed to be of a type that would never have progressed beyond the very small early stage that mammography can detect. But the problem is that we can’t tell which are the benign <a href="http://jama.jamanetwork.com/article.aspx?articleid=1853165">ones and which are not</a>. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/78095/original/image-20150415-19648-cw521g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/78095/original/image-20150415-19648-cw521g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/78095/original/image-20150415-19648-cw521g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/78095/original/image-20150415-19648-cw521g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/78095/original/image-20150415-19648-cw521g.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/78095/original/image-20150415-19648-cw521g.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/78095/original/image-20150415-19648-cw521g.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Electric light and shift work may be factors.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-146043281/stock-photo-side-view-of-a-young-woman-working-on-computer-in-dark-office.html?src=R6VnowHB7Nqr7vQwuzgxsg-1-19">Office worker via www.shutterstock.com.</a></span>
</figcaption>
</figure>
<h2>What about electric light?</h2>
<p>Electric light is a hallmark of modern life. So, maybe the introduction and increasing use of electricity to light the night accounts for a portion of the worldwide breast cancer burden.</p>
<p>This might be because our circadian rhythm is disrupted, which affects hormones that <a href="http://onlinelibrary.wiley.com/doi/10.3322/caac.21218/abstract">influence breast cancer development</a>. For example, electric light at night can trick the body into daytime physiology in which the hormone melatonin is suppressed; and melatonin has been <a href="http://www.ncbi.nlm.nih.gov/pubmed/16322268">shown</a> to have a strong inhibitory effect on human breast tumors growing in rats.</p>
<p>The theory is easy to state but difficult to test in a rigorous manner. Studies have shown that night-working women are at <a href="http://www.thelancet.com/journals/lanonc/article/PIIS1470-2045%2807%2970373-X/abstract">higher risk than day-working women</a>, which was the first prediction of the theory. </p>
<p>Other predictions are that blind women would be at lower risk, short sleepers would be at higher risk, and more highly lighted communities at night would have higher breast cancer incidence. Each of these has some modest support though <a href="http://www.ncbi.nlm.nih.gov/pubmed/19380369">none are conclusive</a>. What we do know is that electric light in the evening or at night can <a href="https://theconversation.com/a-dark-night-is-good-for-your-health-39161">disrupt our circadian rhythms</a>, and whether this harms our long term health, including risk of breast cancer, is not yet clear.</p>
<p>Whatever is going on, it’s important to find answers because breast cancer has become a scourge that now afflicts women all over the world in very large numbers, at almost two million new cases this year alone.</p><img src="https://counter.theconversation.com/content/40036/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Richard Stevens has received funding from the National Institute for Environmental Health Sciences.</span></em></p>Major causes have been identified for most common cancers, like liver and lung. But we still haven’t identified one for breast cancer.Richard G. "Bugs" Stevens, Professor, School of Medicine, University of ConnecticutLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/197952013-11-05T13:43:55Z2013-11-05T13:43:55ZAir pollution ate my computer (and other vital objects)<figure><img src="https://images.theconversation.com/files/34417/original/s5hbq4tb-1383585966.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Subtle impact.</span> <span class="attribution"><span class="source">Anthony Devlin/PA</span></span></figcaption></figure><p>So serious are the effects of air pollution on human health - the WHO <a href="http://www.reuters.com/article/2013/10/17/us-cancer-pollution-idUSBRE99G0BB20131017">recently categorised</a> it as carcinogenic, responsible for 223,000 deaths a year worldwide - that it is easy to neglect its wider impact.</p>
<p>Air pollution damages ecosystems, building materials, and cultural heritage. While health is and will remain the key problem to be addressed, there has been renewed concern recently about the <a href="http://www.environmentalleader.com/2013/10/22/air-pollution-hurts-computers-intel-says/">damage to electronic circuitry</a>, particularly in highly polluted cities in India and China. </p>
<p>This was noticed 40 ago when <a href="http://www.alcatel-lucent.com/bell-labs/about">Bell Laboratories</a> realised that telephone switchboards had a shortened service life when used in polluted areas. Acidic air pollutants react with the electrical contacts made of copper and tin, causing a build up of corrosion products which interfere with electrical current, causing switches to fail. While this is <a href="http://www.hindawi.com/isrn/corrosion/2013/846405/">clearly a problem</a>, the reaction of air pollutants with the <a href="http://www.britannica.com/EBchecked/topic/533976/semiconductor-device#toc34319">solid state components</a> found in electronics also has some uses, for example as air pollution sensors. These still suffer from drift and low sensitivity, but one can envisage a future where tiny air pollution monitors could easily fit into a mobile phone and provide local air pollutant levels.</p>
<p>The range of air pollution impacts not related to health is very large. In 2010 the world was surprised by the natural pollutants ejected into the atmosphere when the <a href="http://www.bgs.ac.uk/research/volcanoes/icelandic_ash.html">Eyjafjallajökull</a> volcano erupted in Iceland. This caused the most substantial disruption of air traffic in 50 years, with the transatlantic routes affected of such importance that it cost the airline industry an estimated US$1.7 billion.</p>
<p>A number of serious incidents in the 1980s occurred when aircraft engines shut down after airliners ran through volcanic ash clouds. In response the <a href="http://www.icao.int/">International Civil Aviation Organisation</a> began to use information provided by <a href="http://www.metoffice.gov.uk/aviation/vaac/">Volcanic Ash Advisory Centres</a> to warn of airborne ash dangers. Where volcanic eruptions are very intense and explosive they can drive gases and dust high into the stratosphere, which can lower global temperatures and extend the whole in the ozone layer.</p>
<h2>Small holes, large problems</h2>
<p>Another much smaller “ozone hole”, but one that can be just as important on a personal level, was the discovery in the 1980s that the ozone produced in photochemical smog attacked the thin latex of condoms causing them to degrade after just a few days. It forced the industry to think about production and packaging.</p>
<p>Chemically speaking, rubber (for example natural rubber, known as polyisoprene; CH<sub>2</sub>=C(CH<sub>3</sub>)CH=CH<sub>2</sub>) has many <a href="http://www.britannica.com/EBchecked/topic/141012/covalent-bond">double bonds</a> that easily react and combine with ozone (O<sub>3</sub>). In a similar way, ozone-rich smogs can attack modern building materials such as plastic fittings, polymer coatings and sealants. Some metals, most notably copper and aluminium that are widely used in modern architecture, are sensitive to these oxidising pollutants typically found in cities.</p>
<p>Our modern atmosphere is quite different from the smoke-filled air of cities in the past. The Roman poet Horace was much concerned about the smoke-begrimed temples of his ancient city. More than a thousand years later architect Christopher Wren described <a href="http://www.enviropedia.org.uk/Acid_Rain/Buildings.php">sulphate crusts</a> on Westminster Abbey that had grown four inches thick from long exposure to coal smoke in London.</p>
<p>Today buildings rarely exhibit such thick sulphate crusts as the days of coal have largely gone. Instead damage is more subtle. In the past the sulphur-laden coal smoke had also killed off lichen that attach to buildings. Now sulphur dioxide pollution has been replaced by nitrogen oxides, which form deposits on stone facades, essentially providing a fertiliser of sorts that encourages biological growth.</p>
<h2>Outdoor damage indoors</h2>
<p>Air pollutants can also leak indoors, and potentially damage objects in museums, art galleries and historic houses. To some extent the problem can be alleviated in museums and art galleries, but historic houses are not well suited to modern air conditioning. Even visitors themselves can be a source of damage - their presence changes the humidity of indoor air and they shed pollutant dust and fibres from their clothes as they move among the displays. The current enthusiasm for open displays means these deposited pollutants must be regularly cleaned off.</p>
<p>However, the aesthetic impact of air pollution is not always negative. Some of the chemical reactions taking place in the atmosphere contribute to our appreciation of landscapes. Natural chemicals given off from trees, such as pinene from coniferous forests or eucalyptol from eucalyptus trees in Australia, react to form fine particles. In the case of eucalyptol, these particles scatter blue light, making distant objects appear blue – hence the appearance of the <a href="http://www.bluemts.com.au/">Blue Mountains</a>. The importance of cool tones in depicting distant objects was described long ago by Leonardo da Vinci.</p>
<p>In its own way air pollution has had a great impact on art. Take the abstraction evident in Monet’s <a href="http://en.wikipedia.org/wiki/Houses_of_Parliament_series_(Monet)">paintings of Westminster</a> done more than a century ago. He particularly chose to visit London in winter to capture the vivid colours of its famous polluted fog. <a href="http://vichist.blogspot.co.uk/2006/11/london-fog.html">Victorian fog</a> became a metaphor for confusion and lack of clarity, hence its use in Sherlock Holmes stories. Even today it can be used to wield the same symbolism: in <a href="http://www.kingsspeech.com/">The King’s Speech</a>, a film about King George VI and <a href="http://www.stammering.org/logue.html">Lionel Logue</a>, a confused Duke of York wanders off into the fog. Clearly, the effects of air pollution in all its forms is much broader than one would think.</p><img src="https://counter.theconversation.com/content/19795/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Brimblecombe does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>So serious are the effects of air pollution on human health - the WHO recently categorised it as carcinogenic, responsible for 223,000 deaths a year worldwide - that it is easy to neglect its wider impact…Peter Brimblecombe, Associate Dean, Chair Professor of the Atmospheric Environment , City University of Hong KongLicensed as Creative Commons – attribution, no derivatives.