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Trevor Hancock: We carry from birth a body-burden of toxic chemicals that we add to along the way

Decades of lax assessment coupled with the assumption that chemicals are innocent until proven guilty have left us and the ecosystem with a burden of toxins
Pesticides like chlorpyrifos, long targeted by environmentalists because it poses risks to children and farm workers, are applied on numerous crops, including soybeans, fruit and nut trees, broccoli and cauliflower. Many synthetic chemicals, including pesticides, are designed to be stable and not easily broken down by nature, which makes them persistent, writes Trevor Hancock. AP FILES

Last week, I noted the ecological footprint does not do a good job of including some forms of wastes.

While biological wastes and materials going to landfill or recycling are accounted for, “Toxics and pollutants released from the human economy that cannot in any way be absorbed or broken down by biological processes … cannot be directly assigned an Ecological Footprint,” notes the Global Footprint Network.

So on top of learning about and reducing our ecological footprint, we need to also understand and reduce what we might call our “toxics footprint.”

Unfortunately, these pollutants include plastics, heavy metals such as mercury, and many synthetic chemicals, including pesticides, PCBs and PFAs (found in non-stick pans, fabrics, furnishings, shampoos and cleaning products), that were designed to be stable and not easily broken down by nature.

Thus, they are persistent — or in popular parlance, “forever chemicals.”

We have known of their potential ecological and health impacts for decades — Rachel Carson, in her book Silent Spring, sounded a warning about pesticides way back in 1962, more than 60 years ago.

In the planetary boundaries framework, they are part of one of the nine planetary boundary systems, the broader class of “novel entities:” “new substances, new forms of existing substances and modified life forms” including “chemicals and other new types of engineered materials (read nano-particles) or organisms not previously known to the Earth system (read GMOs) as well as naturally occurring elements (for example, heavy metals) mobilized by [human] activities.”

The big problem with these novel entities is twofold: First, human activity disperses them widely around the planet and across ecosystems, contaminating many life-forms — a process known as eco-toxicity.

Second, for some of these novel entities (in particular, persistent organic pollutants or POPs, heavy metals and nano-particles) nature — through a process known as bio-concentration — brings them together and concentrates them up the food chain.

And who sits at the top of those food chains? Us, making this process perhaps the most elegant and potent form of nature’s revenge on humanity that I can think of.

But it’s not just us. It’s other predators, too. Locally, we have seen high levels of POPs threaten the health of orcas, while DDT nearly wiped out bald eagles and other raptors in the 1970s.

We and they all carry from birth a body-burden of these chemicals, many of which are known to be toxic in various ways — and we add to that burden throughout our lives.

But even worse, in many cases, we do not know what their toxic effects are, and we certainly don’t know the effects of their multiple potential interactions.

This is hardly a new problem. An important 1979 report on ecotoxicity from the Canadian Environmental Advisory commented on “the unavoidable limits to scientific knowledge and the limitations of the classical scientific method, particularly as it relates to toxicology.”

Forty years later, nothing much has changed. In finding last year that the planetary boundary for novel entities had been transgressed, Linda Pearson and her colleagues noted: “There are an estimated 350,000 chemicals (or mixtures of chemicals) on the global market. Nearly 70,000 have been registered in the past decade” — and many of those have been registered only in emerging economies, where chemicals management capacity is lower.

Even where capacity is high, they note, such as the European Union, of 12,000 or so chemicals registered with the 10 year-old REACH program, 80 per cent are yet to be assessed.

So what we have, in effect, is a decades-long unauthorized experiment to find out what happens when we expose humans, other species and entire ecosystems to long-term contamination with multiple, low-dose, persistent toxins and loose novel entities into our ecosystems.

This results from decades of lax assessment of these chemicals, coupled with the bizarre assumption that chemicals, like people, are innocent until proven guilty.

All this has been facilitated by a chemical industry that has shown time and again that it will fight tooth and nail to keep its products on the market, and will always put its profits over the wellbeing of people and the planet.

That is our toxics footprint, and it is a dangerously unknown and shameful legacy.

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Dr. Trevor Hancock is a retired professor and senior scholar at the University of Victoria’s School of Public Health and Social Policy