Bisphenol A (BPA for short) is a common chemical used to harden plastics and make resins used for dental fillings among many other commercial applications. It’s also an endocrine disruptor. In a recently published report, female rats exposed to BPA as pups at levels below EPA standards developed polycystic ovaries as adults. The hormone profiles for these rats were high in estrogen and testosterone and low in progesterone.
On the same note, the Endocrine Society is having its annual meeting this week in San Diego. At a symposium titled Endocrine Disruptors of Reproductive Function, research will be presented showing that women with polycystic ovary syndrome have higher body burdens of BPA.
One of the more surprising exposures to BPA was revealed in a review released last week by the organization Environment and Human Health. They found the green building standards established by the Leadership in Energy and Environmental Design program (LEED) focus on energy efficiency but not on health. It was friendly criticism but nevertheless found that a construction project could receive the highest LEED designation possible while exposing inhabitants to BPA-containing materials. The green building standards simply don’t address those issues.
For a hostile criticism of industrial practices that expose people to endocrine disruptors, we can still remain within the energy economy. The documentary “Gasland” is about a practice called fracking, short for hydraulic fracturing. It’s a method for extracting methane (that is, natural gas) from rock by blasting it with water, sand, and chemicals. The waste from this process gets into the water supply and into the air.
Theo Colborn, the Rachel Carson of endocrine disruptors, estimates that of the 278 chemicals used, virtually all have known health risks and almost half are known endocrine disruptors. The fight over exposures to these dangers is an old one: local people trying to protect their communities against energy companies. You won’t be surprised to know that special legislation by the US Congress, desperate to support domestic energy sources—especially clean energy such natural gas—exempted fracking from the Safe Drinking Water Act and the Clean Water Act.
Seeing Theo Colborn’s name in the news about this injustice caused me to wonder what we’ve learned about endocrine disruptors since publication of her groundbreaking book Our Stolen Future. She talks about the toxicity of BPA in her book—and we’re still struggling to get it properly regulated, even though it’s become something of a legislative and regulatory cause célèbre. So we’ve learned, once again, that the path to humane regulation of toxins is long and torturous. Here’s what else we’ve learned.
Endocrine disruptors are everywhere. Every human being on the face of the earth has been exposed to them. Everyone. Everyone is likely to have at least 100 chemicals in their blood or sequestered in their tissues that would not have been there a century ago. Every child born in the last 30 years was exposed in the womb.
Endocrine disruptors are potent at low doses. The old way of thinking in toxicology was that there is some dose below which there is no effect. But this way of thinking used poisoning as its model so that a safe dose was one that did not cause an acute response. What the science of endocrine disruptors has shown us is that a very small dose at a specific stage in an organism’s development can have a profound effect on its viability and health.
Endocrine disruptors affect every chemically mediated signaling system, not just sex hormones. Thyroid signally is affect. Retinoids are affected—these work during fetal development to differentiate tissues. Glucocorticoids are affected—these affect energy metabolism, stress response, body mass regulation, and the central nervous system.
The list of endocrine disrupting chemicals continues to expand dramatically. The list now includes persistent organohalogens such as dioxins and PCBs, food additives such as BHA, pesticides such as Atrazine, phthalates, and metals such as arsenic.
Endocrine disruptors affect health with long latency periods. Exposed as a fetus, the adult will suffer the health effects. Exposed as an adult, subsequent generations will suffer. The study I cited is an example: early exposure to BPA increased the risk of polycystic ovaries. Ominously, this area is one of the least studied.
Endocrine disruptor research is biased in favor of finding no association with health risks. Tracking people’s exposures and health outcomes outside a controlled experimental environment is a problem. Such a setup is inherently biased toward producing a false negative—that is, showing no association when in fact there is one. Of course, this emphasizes our personal and community experiences as involuntary test subjects in the uncontrolled experiments now being conducted by industry. But that doesn’t count as science.
This all sounds like bad news. It is.
But there’s good news. There are people working hard for better regulation and against production of endocrine disruptors. All good, but it’s defensive. It’s “No!” Where do we find “Yes?” One of the basic principles we promote on this show is to do the simplest things first. Simplest, not easiest. We are inundated with endocrine disruptors because of the way in which production is organized, with health effects not even a consideration so far as producers are concerned until it’s forced on them. But we are capable of changing that. How? There are many ways. Here’s just one. The US Social Forum takes place this week in Detroit. It’s motto is “Another world is possible. Another US is necessary.” Yes.
