Insight

Science and the PCB problem

By Tim Zink
Special to The Star
12-08-2002

The more science tells me of man-made neurotoxins like dioxins and PCBs, the more I realize how important it is for a thorough cleanup and detailed epidemiological study in Anniston to get under way, yesterday. While negative effects of these materials on the human body have been known for more than a half-century, two recently released reports have strengthened my understanding and stirred this conviction. The first comes from a team of Dutch researchers, which studied the health effects of prenatal exposure to PCBs and dioxins. Because they cross the placenta during pregnancy, these compounds reach and enter fetuses during the most delicate of stages. Yet strikingly little had been known about exactly what happens to fetuses fed doses of these synthetic chemicals. Begun in 1990, the Dutch study has shed some light. It evaluated the development of more than 150 children who had been exposed to PCBs and dioxins while still in the womb. In earlier inquiries, these children were found to have below-average psychomotor skills at 3 months of age and lower cognitive abilities at 42 months. Sobering as those early findings were, the most recent conclusions by the Dutch research team dwarf them. Focusing on the play behaviors of children at an average age of 7.5 years, the researchers found a link between prenatal exposure to PCBs and altered play behaviors that reflect fundamental sex differences. The researchers asked parents to complete detailed questionnaires that gauged, among other things, their child’s preference for tools or dolls, and playing sports or dressing up in girlish clothes. The parents’ responses were compared to the children’s PCB- and dioxin-exposure levels. Higher prenatal exposure to PCBs was associated with less masculine play behavior in boys and more masculine play behavior in girls. Higher prenatal exposure to dioxin was associated with more feminized play behavior in both boys and girls. The researchers suggest that their results may indicate the effects of steroid hormone imbalances caused early in development by prenatal exposure to PCBs and dioxins. Steroid hormones, such as estrogens and androgens, play important roles in the growth of the central nervous system. They also influence the reproductive process. The researchers claim that this is the first study in humans to document clear effects of environmental PCBs and dioxins on behavior that shows marked sex differences. They recommend following up this study with more detailed monitoring, noting that the current body of scientific knowledge on how PCBs and dioxins affect steroid hormones is limited. To me this illustrates one of the saddest realities of our age: We have allowed powerful chemical agents to infiltrate and influence vital human processes without understanding the most basic effects they will have on our lives — and inestimable future generations. Yet even as we begin to grasp the health detriments of a select few chemical compounds that have aroused public scrutiny, usually for their overt and obvious offenses against the public health, scientists still must navigate vast knowledge gaps to advance their research. To me, when a substance can dull or erode the very things that define us as humans — our thinking, our dexterity, our sex — no gaps should be allowed to exist in our understanding of its destructive potential. This theme is repeated throughout an April 2002 General Accounting Office report on the Environmental Protection Agency’s Draft Reassessment of Dioxins. The EPA reassessment, which officials say will be released in its final form by the end of this year after almost 10 years of formulation and review, promises to provide the most complete overview to date of the negative health effects of dioxins and PCBs. By studying 29 of the most toxic of the several hundred known dioxin compounds — including PCBs, which it characterizes as “dioxin-like” — the EPA was able to draw some conclusions on the entire chemical family.

Because the EPA reassessment is currently in draft form, it may not be quoted and the agency’s public affairs office is tight-lipped on the report’s final language. It has been in draft form for quite some time and plausibly has been ready for final approval and release. Critics see this as an indication that the Bush administration is planning to try to bury or dilute the final reassessment to protect the interests of industry. But the GAO review largely speaks well of the EPA’s methodology and findings, suggesting that the administration will be unable to subvert the soundness of the EPA’s science. It also offers a window unto the EPA’s conclusions — conclusions the agency shares with the World Health Organization, which has likewise probed the issue deeply. “Dioxins can cause a variety of both cancer and non-cancer health effects,” the GAO review reads, summarizing the conclusions of the draft EPA report. “Dioxins act in the same way within the body to cause the effects observed in animals and humans. Dioxins adversely affect human health at lower exposure levels than previously thought, and some effects could occur at or near levels to which the general population is now being exposed.” It should be noted that the EPA based these conclusions on Department of Agriculture estimates of dietary exposure to PCBs and dioxins that were gathered near the start of the 10-year investigative process, when the chemicals were common at higher levels in our food supply. Years of prohibiting the trade of many of these substances hopefully will have decreased the exposure levels in much of the general public. Then there’s Anniston, where many folks have unknowingly ingested obscenely high levels of synthetic chemicals. No matter how fast exposure levels dissipate in the wider population, the contamination will remain acute far longer here. This we know. Unknown are many of the specific health effects that have befallen certain of Anniston’s citizens as a direct result of exposure to these neurotoxins. While anecdotal evidence abounds, scientific proof continues to elude, in largest part because studies into the specific mechanisms by which PCBs and dioxins damage the body have yet to be undertaken. Does Anniston have higher incidences of reproductive failure or complications, kidney and liver diseases, and cancer than the wider public? If so, how does it best deal with the risks? The first step toward answering these life-and-death questions has been taken, or at least planned. The cleanup guaranteed by Solutia Inc. and the federal government should cut the risks. But in order to cut the risks, it needs to be more than a plan. It needs to be put into motion on the ground as soon as possible. History is full of worthy plans abandoned when a society’s priorities shifted. After waiting for federal cleanup assistance for so long, the last thing Anniston needs is further delay. Within the last year, large-scale cleanups promised to hundreds of communities via the federal Superfund have been put on hold as the fund’s financial reserves, once replenished by corporate taxes but now by individual taxpayers, have shrunken dramatically. This should serve as a warning. Now that a cleanup deal for Anniston finally has been struck, it needs to progress. And the cleanup, whenever it begins, just begins the solution. By undertaking a detailed and lasting epidemiological study, as has been advocated by The Anniston Star and several community groups, a robust understanding of the intricate changes deep within the human body caused by these chemicals can be advanced and spread. Even though the EPA has allocated funding to the Agency for Toxic Substances and Disease Registry for such a study, the funds have not yet been appropriated. They must be. Tim Zink is an editor of Blue Ridge Press, a syndicated column service publishing on Southeastern environmental issues from Purcellville, Va.