Posts Tagged ‘Risk Assessment’

It may come as a shock, but the EPA and industry view exposures to toxic chemicals in basically the same way that a famous 16th-Century  occultist named  Paracelsus did over 500 years ago: The amount of exposure to a chemical determines its toxicity; the higher the dose, the more toxic it is. The lower the dose, the more benign. "The dose makes the poison." 

This approach says there's a linear one-to-one relationship between volume and harm. It's the basis of all federal, state and local environmental health regulation. It's what drives government "risk assessments." It's what allows there to be such things as "safe levels" of things that don't sound very safe.

But, what if this approach didn't capture all of what was going on physiologically between poison and victim? What if there were different effects happening at the cellular level?  What if, like the Renaissance-born theory of Newtonian physics, it couldn't account for phenomenon on a smaller-scale because it didn't have the ability to see it? What if there were certain poisons that,

"depict a weird world of endocrine disruption that is as different from traditional toxicology as quantum mechanics is from the staid clockwork of Newtonian physics. When even minuscule quantities of BPA and other disrupters interact with hormone receptors at crucial moments in development — activating, jamming, hijacking or otherwise messing with their normal function — they can give rise to strange-looking experimental results, especially when other hormones are thrown into the mix."

From the journal Nature comes a case study in why no self-respecting thinking person would trust the current regulatory system to give them the final word on whether any given chemical exposure is "safe" or not.

A citizen can't underestimate the kind of threat this research presents to the Environmental Industrial and Legal Complex. Every permit ever written and awarded. Every environmental law every passed. They all depend on a Paracelsusian view of the world. Prove a different world exists and it turns everything upside down.

"A growing number of academic researchers are making just such a claim for endocrine disrupters, a large group of synthetic chemicals able to interact with cellular hormone receptors. These compounds, which range from the common weed killer atrazine and the plasticizer bisphenol A (BPA) to the antibacterial agent triclosan (used in cleansers) and the vineyard fungicide vinclozolin, don't play by the usual rules of toxicology. On the basis of conventional high-dose testing, regulators have set maximum acceptable levels for each of them that assume all doses below that level are safe. But academic researchers who have studied a wider range of doses, including very low ones found in the everyday environment, say that their experiments usually do not generate the tidy, familiar 'ski-slope' dose-response graphs of classic toxicology. Instead, most endocrine disrupters have 'non-monotonic' dose-response curves, meaning that their slopes change at least once from negative to positive, or vice versa, forming 'U' shapes, inverted 'U's or even stranger shapes that resemble undulating Chinese dragons."

It's not just endocrine disruptors that are challenging tradition. We're already seeing the contradiction between the latest science and regulations when it comes to old-fashioned poisons like lead and soot. There's a scientific consensus among the frontline researchers that there's no safe level of exposure to either one of these toxic substances, And yet, permits are still being written to allow what regulators claim are "safe levels" of them to be spewed into the air and our lungs.

Locally, UT Southwestern epidemiologist Dr. Robert Haley's groundbreaking work on Gulf War Syndrome has found similar effects in studying exposure of veterans to very low doses of nerve agents. Levels of substances that weren't supposed to make people sick individually seem to have a harmful synergistic effect when combined.

The more we can see what's happening at the smallest levels of things – whether its the vibrations of atoms in the chair you're sitting in, or the nuance of chemicals in the cells of a developing fetus – the more we find out that things are more complicated than they appear. Science is pushing us in the direction of a "Precautionary Principle" approach to regulating human chemical exposure. That's a radically different perspective that undermines the billions invested in the status quo allowing continual low level poisoning. After 500 years, maybe it's time to find a new model.