Last week saw CleanUp 2013, a worthy conference on environmental remediation hosted by the CRC for Contamination Assessment and Remediation of the Environment. However, in amongst the media releases on state of the art science to clean up our polluted landscape* was one claiming Every human ‘is now polluted’.
In the literal sense this is true. Pollutants have touched the furthest corners of the globe, even Antarctica has turned up traces of pollutants. And all of us bear some traces of pollutants. But the authors want to draw a far scarier picture.
“….. Healthcare costs due to degenerative diseases are now crippling the US Obama Government. The economic losses from sickness caused by chronic chemical exposure are rising in all societies.”
Ummm, right, yeah chronic chemical exposure is crippling us with sickness. As shown by the graph to the left. On, no, wait a second, that shows that in Australia people at the age 65 actually had more disease free years of health than in 1998.
But wait a second, we’ve all heard on the news of the coming problems with chronic disease. How can this be if we are living healthier?
Because we are living longer, Even if more people aged 65 live longer before disease strikes, the simple fact that more people over 65 are living longer means we have a growing burden of chronic disease when it does strike. No need to invoke chemical exposure for this.
The reasons we are living longer also suggest the chronic exposure to trace chemicals is not to blame is why life span is increasing. Death rates for cardiovascular disease, our biggest killer, and cancer, our second biggest killer, are both falling (or at least not rising for cancer). Okay, we have better treatments for both diseases, but the incidence of cardiovascular disease is falling, in part due to falling rates of smoking. Cancer is more complex, lung cancer in men is falling, but still rising in women because of changes in smoking habits. Breast cancer rates are pretty flat.
Still, there is not much evidence from either cardiovascular disease or cancer that chronic exposure to trace chemicals is crippling us (or at least, more than in the past when infectious disease ran riot, fungal and other toxins were prevalent in food and people put plaster in flour to bulk it out).
What about type 2 diabetes? We have an epidemic of that. But we also have increasing obesity and decreasing physical activity, both significant risk factors for type 2 diabetes, we don’t need to invoke chronic exposure to trace chemicals to explain our rising rates of type 2 diabetes.
Also in Australia the incidence of asthma has actually fallen by 25% in young people over the past 10 years. The fall in Australia is possibly related to our successful anti-smoking campaigns, and chronic exposure to trace chemicals is certainly not responsible for this fall.
I don’t wish to trivialize the issue of environmental pollutants. This year marks the 51st anniversary of the publication of “Silent Spring”, a wake up call to the effects certain synthetic chemicals on the environment. Since then we have seen devastating examples of environmental contamination from Bophal to Minimata. Closer to home people in Port Pirie face ongoing issues with lead contamination, and in the suburb of Birkenhead in Adelaide public housing tenants were relocated due to contamination of their homes with persistent pollutants.
But along with these examples of environmental contamination there has arisen a degree of chemophobia, a fear of all chemicals regardless of their concentration and potential harms, and a yearning for an environmental purity that never was. This is reflected in the media release.
“One US study found 232 industrial chemicals and pollutants, including known carcinogens and complex mixtures, in the (umbilical) cord blood of newborns. This means that children are coming into the world already polluted with things that could kill them.”
That number, 232 industrial chemicals, sounds really scary. But if your analytical techniques are good, you can detect minute and irrelevant concentrations of these substances.
To remind you, yet again, of what my blog patron says. It’s the dose that makes the poison. Merely detecting a potential toxin does not mean its causing you harm. After all, formaldehyde is an toxin, but your body makes small amounts of formaldehyde as part of normal metabolism, and finding these levels in your body is not an indicator of harm.
The 232 figure comes from this study which looked at all of 10 babies. Also, no child had all 232 chemicals, most had a lot less. And when we look at the published results, the figures are even less scary.
Lets take lead. Lead is a known neurotoxin, but it is also a natural and ubiquitous part of our environment. You will never have zero lead in your body, even if you lived in a hermetically sealed bubble.
Looking at these 10 newborns, their average blood lead levels were 0.34 micrograms per 100 millilitres of blood. This is well below the Australian threshold safety limit of 10 micrograms per 100 millilitres of blood.
If you look through the list at mercury, PFO’s and PCB’s, you will find that they are all below the thresholds for toxic effects. Which is pretty good, but the report spins this finding as bad. Still 10 children is a bit unrepresentative of the larger population.
The US Centers for Disease Control has been looking at 212 environmental chemicals in over 2000 people of all ages for a decade. Their recent results show that the concentrations of chemicals in our bodies has been decreasing over the decade for all age groups. Those that have detectable levels that is. These results counter one of the key themes in the press release.
And then there is this statement in the press release:
“The rise in autism spectrum disorders is considered by many scientists one possible outcome of this process”
Yes, we live in an environment which has a range of synthetic chemicals present at low concentrations. But in many ways we have swapped highly toxic natural products for these less toxic synthetic chemicals. In developed nations we no longer have significant concentrations of the highly carcinogenic (and liver damaging) aflatoxin or orchitoxin in our foods. Contamination from toxic plant alkaloids, an issue in our grandparents and great-grandparents days, is now minimized. In Taiwan, the presence of the toxic alkaloid aristocolic acid is thought to be responsible for the high levels of rare kidney cancer there.
In contrast, we have very little evidence that the background levels of industrial chemicals (as opposed to specific incidents of contamination with high levels of these chemicals) produce detectable harm. Several studies have been unable to attribute any level of cancer to these chemicals (as opposed to say, cigarette smoking, or domestic fuel use).
We should not be complacent about the presence of these chemicals in our environment, we have environmental exposure laws for good reason. But action on environmental toxins should be based on good evidence. Breathless press releases about polluted people only creates panic and ultimately harms the goal of effective environmental regulation.
*some of which have obscure titles which would get them defunded by the current Liberal government if they go ahead with their election promises in this area.