The World Health Organization estimates that one in every 12 deaths worldwide is due to chemical exposure, sometimes acute but mostly chronic. This eclipses the annual death tolls from malaria, car crashes and HIV/AIDS.
Clearly, we need to be doing more about major health risks like malaria, as well as other environmental risks to health from ongoing changes to the world’s climate, soils, ocean chemistry, biodiversity and other natural systems. But a new book raises an important question: what are the consequences of diverting our gaze from another global environmental health hazard?
The dangers associated with urban-industrial air pollutants have long been apparent, though they are now also implicated in old-age mental decline. Yet apart from acute environmental disasters such as Minamata in the late 1950s and Bhopal in 1984, most of the rising tide of long-lasting synthetic chemicals, heavy metals and other contaminants diffusing through the environment has been invisible.
Further, the ecological and health risks are not well understood – and are widely assumed to be negligible because actual exposures are presumably low.
That assumption is challenged by Australian science writer Julian Cribb in his new book Poisoned Planet. He argues that the Earth’s surface is now chemically contaminated from the Arctic to the ocean floor – and that each of us is unwittingly a “walking contaminated site”.
A rising tide of toxins
In Western countries, national concerns and legislation over environmental contamination by human-generated chemical effluent and wastes peaked in the 1970s.
Yet since 1960, annual synthetic chemical production worldwide has increased 20-fold. Over 140,000 newly synthesised industrial and agricultural chemicals have been registered in North America, Europe and Australia.
Persistent organochlorines such as DDT and polychlorinated biphenyls (PCBs), heavy metals (especially lead and mercury) and many volatile aromatic hydrocarbons all have known toxic effects. And what of nano-pollutants, with their bioactivity transformed by miniscule size?
Climate change can cause floods, mobilise mosquitoes and diminish harvests, and the adverse human impacts are easy to see.
In contrast, long-lasting chemical contaminants act more covertly, spreading through air, soil, water, foods and ecosystems. Some are benign, some overtly toxic, but many act by insidious weakening or disruption of healthy biological functions: affecting specific organ systems, altering hormonal profiles, switching genes on or off, and contributing to various cancerous, neurological and behavioural changes. Humans, other species and ecosystems are thus endangered.
Drawing on diverse scientific research, a coherent picture emerges in this book of wide-ranging potential harm to bodies, brains and babies from chemical contamination, mostly food-borne.
Some of Cribb’s evidence is unavoidably thin, some is contested. But when viewed overall, it’s hard not to agree that humanity is fouling its nest.
For instance, a recent European-wide study concluded that the ecological risks from toxic chemicals greatly exceed previous assumptions.
Many persistent contaminants have spread globally into polar ice, mountain glaciers, seals and whales. Humans dine at nature’s high table, often eating industrially-produced food, grown, processed and packaged in ways that impart traces of many chemical hazards – a trade-off for the undoubted privilege of abundant and affordable food.
A silent epidemic?
There is much to be celebrated about modern life.
Urbanisation and industrialisation have ushered in the high-water mark of human material achievement. Poverty, starvation, infectious diseases and brute labour, though still with us, are no longer the norm. The contagion, filth and stench of medieval times has given way to clean water, sanitation, safe food, vaccines, better housing – and longer lives.
But is it mere coincidence that rising rates of cognitive impairment and child-and-adolescent behavioural abnormalities in recent decades have accompanied the increase in low-level environmental chemical exposures? We know that foetal and perinatal biology renders tiny humans vulnerable to toxic insult, so it is not unreasonable to at least ask such questions. And are increases in allergic conditions, even autism, also part of this picture?
Scientific evidence is also accruing that some chemical exposures contribute to obesity and the diabetes that is often a consequence of that obesity.
The average person’s in-out energy imbalance in modern society – that is, we’re consuming more food energy than we’re physically expending – is an acknowledged cause of weight gain. However, biologically, that energy imbalance exerts effects via various metabolic, cellular and hormonal changes, as do various assimilated chemical contaminants.
A thought experiment shows the difficulty of assessing consequences of chronic low-level exposure to chemicals. If the urbanised Romans’ use of lead for plumbing and in drinking vessels caused gradual intellectual impairment and loss of imperial authority, who would have noticed the link, or foreseen the future consequences?
What we can do
Poisoned Planet may unsettle some readers, and raise eyebrows among others.
But Cribb’s message – emphasising the need for both information and precaution – warrants our serious attention. The problem of persistent environmental chemical contamination could well have long-lasting effects on human biology, health and longevity, and we owe it to ourselves and coming generations to debate the questions he raises.
In the meantime, there are solutions to toxic pollution that we can act on today. These changes include improving the way we grow, manufacture, transport, consume, and dispose of chemical wastes.
International conventions on chemical contamination must be ratified and complied with.
And citizens all over the world can also exert influence through existing social and political channels.
For inspiration, we need look no further than China, where the spread of the internet has helped millions of individuals speak up with a common voice about environmental hazards – such as deadly air pollution – to demand genuine improvements to clear the air.
Poisoned Planet: How constant exposure to man-made chemicals is putting your life at risk by Julian Cribb is published by Allen and Unwin.