Can't Lay This Burden Down

The first body burden post I wrote, The Unbearable Burden, was about the recently released results of the study done on the cord blood of newborns by The Environmental Working Group and Commonweal, showing that babies are now born with as many as 287 industrial chemicals, pollutants and pesticides in their blood. These same folks did the first-ever body burden study on "identified" subjects in 2003, Body Burden 1. In the second post on this subject, Better Living Through Chemistry, I said that the CDC would soon be releasing the results of the third biennial National Report on Human Exposure to Environmental Chemicals. They were announced last Thursday, and it's possible to read the whole report in PDF form on the CDC site. The "summary" of the report is 18 pages long, so if you can plow through the entire report itself - I stand in awe. What the CDC and private agencies are doing is known as "biomonitoring"...

Body burden assessment or biological monitoring ("biomonitoring") is the simultaneous measurement of the presence and concentration of chemical compounds in human biospecimens like blood, urine, breastmilk, adipose tissue, hair, saliva, and meconium that, apart from occupational exposure or other special circumstances, usually are found at levels beneath those of traditional toxicological concern. A new framework is emerging in toxicology, however, that emphasizes the importance of exposures to complex mixtures of chemicals, even at low levels of exposure, and the timing of exposure at critical periods of development. (Commonweal)

There was some small measure of good news in this year's report: lead levels have dropped dramatically, and exposure to second-hand smoke is down. The drop in blood levels of lead is mostly due to the removal of lead from gasoline, and the exposure to second-hand smoke is connected to stronger anti-smoking laws across the country. However, blacks and children still have higher levels of the chemical used to measure second-hand smoke, cotinine, a breakdown product of nicotine.

The CDC's Environmental Health Lab tested for 148 different chemicals found in the blood and urine of 2400 volunteers. Of these, 38 have never been measured before in the population. Among chemicals tested for are mercury, insecticides, pesticides, weed killers, dioxins, furans PCBs, and a new group - the phthlates. Six of these have been banned across the European Union and Greenpeace has been campaigning against them since 1999. They are associated with vinyls, plastics, and cosmetic products.

So, biomonitoring by both private and goverment groups has now shown that our bodies (across the population spectrum: age, race, occupation, etc) are liberally laced with chemicals. Before this work, the focus was on small groups of people exposed to large amounts of toxins. Now, as Charlotte Brody, of Commonweal, writes:

The old story about toxic chemicals was about toxic waste sites in someone else's backyard, and that only high levels matter. Toxic chemicals were not linked to health impacts, unless you happened to live next to a Superfund site or were exposed occupationally. The new story is that we are all exposed to complex mixtures of chemicals all the time and, unexpectedly, they are capable of interfering with normal biological processes even at low levels of exposure. They aren't toxins or poisons in the traditional sense, in that they may not be acutely toxic at the time of exposure or very soon thereafter.

Rather, the chemicals that make up our body burdens form an internal reservoir of toxicity capable of delivering small amounts of toxic insult on an ongoing basis. For individuals exposed very young, the effects of chemicals may be more severe, but such effects may not appear for decades after the initial exposure. Toxic chemicals are contaminants hijacking control of biological processes, especially endocrine-disrupting chemicals freely crossing the placental barrier and entering the fetus.

What no one yet knows, with any degree of proof or certainty, are the health effects of this chemical stew within us. However there is a wide array of health conditions now plausibly linked by scientific research to exposure to different contaminants. Knowledge of this chemical burden will hopefully create an opportunity to attract new constituencies into public health advocacy. Doctors and scientists alike agree that research on the connections between health problems ranging from childhood leukemia to Alzheimer's Disease and this chemical burden must be ongoing. The problem is that research takes years, decades. How many of us and of our children will die of these consequences before the links are proven? Clif Curtis, director of the World Wildlife Fund's Global Toxics Program, summed it up nicely: "The CDC's latest research confirms that the American public is exposed to widespread contamination by toxic chemicals, the effects of which are unknown."

Note: This is a vast subject, and this is already a lengthy post. I intend to make this the subject of several more posts, so - be warned, there's a dance in the old dame yet.

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