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Question #1: How does this study compare to the government's National Exposure Report?
Question #2: Why test for chemicals in people? Risk assessment, public health policy
Question #3: Why did you test just 10 newborns?
Question #4: How do industrial chemicals get in my body?
Question #5: How can I reduce my chemical exposures?

Question #2: Why test for chemicals in people? Applications of body burden (biomonitoring) data for human health risk assessment and public health policy

Scientists and regulators use body burden data (biomonitoring studies) to estimate human health risks from exposures to industrial chemicals, to set public health policies that protect against these risks, and to track the success of these policies in reducing exposures. The applications of biomonitoring are rapidly expanding beyond its traditional use in occupational medicine and poisoning cases to new applications in measuring exposures and estimating health risks among the general population (Thornton et al. 2002, EWG 2003, Sexton et al. 2004, CDC 2003). Public health officials have recently used body burden data in assessing health risks for chemicals described below, all of which found in this study in newborn umbilical cord blood:

• Mercury. When CDC body burden studies showed high blood levels of mercury in women of childbearing age, government scientists assessed the data to show that one of every six women is exposed to mercury in excess of safe levels, through their consumption of mercury-contaminated seafood. These analyses were benchmarked back to seminal umbilical cord blood studies linking mercury to brain damage among children exposed in the womb (Grandjean et al. 1997). FDA then designed and publicized seafood consumer advisories that are intended to lower women's blood mercury levels (Carrington et al. 2004, FDA 2004). EWG's investigation identified mercury (as the form in seafood, methylmercury) in all 10 newborns tested.



• Scotchgard. Beginning in 1997 3M found the active ingredient in Scotchgard (PFOS) not only in blood from U.S. blood banks, but also in the blood of 600 children tested. Concurrently, 3M was learning that Scotchgard induces serious birth defects in laboratory studies, results that government scientists called "disturbing." EPA officials pressured 3M to take Scotchgard off the market. According to government officials, Scotchgard "combine[s] persistence, bioaccumulation, and toxicity properties to an extraordinary degree" (Auer 2000). In the past three years 3M has completely reformulated the product, although the persistent PFOS chemical will continue to pollute people, including babies in the womb, for generations to come. EWG's investigation identified PFOS in all 10 newborns tested, and represents the first reported detections of PFOS in U.S. cord blood.



• Teflon chemical PFOA. In the wake of the Scotchgard phaseout, EPA turned their attention to a closely related chemical, the Teflon ingredient PFOA. EPA conducted an assessment of human health risks benchmarked on measured levels of PFOA in the blood of the general population (EPA 2005d). This assessment, currently under review by EPA's independent Science Advisory Panel, was conducted to guide EPA in designing policies necessary to lower human exposures to PFOA. The Agency's priority review and assessment of PFOA is driven by its ubiquity in human blood — it pollutes the blood of more than 95 percent of Americans — combined with the chemicals' broad toxicity and the fact that, among all human blood pollutants, PFOA belongs to a chemical family (perfluorochemicals) that is uniquely persistent in the environment: PFOA never breaks down. EWG's investigation identified PFOA in all 10 newborns tested, the first reported detections of the chemical in cord blood from the general population.



• Dioxin. In a politically controversial series of exposure and human health risk assessments, EPA has consistently relied on body burden measurements of dioxin — in breast milk and other human tissues — to estimate exposures and health risks for the notirious family of dioxin-like chemicals (EPA 2000a). EWG's investigation identified dioxin-like chemicals in all 10 newborns tested.

Biomonitoring can fill data gaps and reduce uncertainties inherent in traditional exposure and risk assessment, leading to more fully informed public health policies. As measures of "internal dose," biomonitoring data comprise exposure estimates more direct, and with lower uncertainty, than those that scientists derive from traditional algorithms — methods that compound uncertainty by combining estimates of behavior patterns, pharmacokinetics, and external doses. When compared against measurements or estimates of internal dose from toxicology studies, biomonitoring data also providing a more direct estimate of potential hazards by reducing the need to compensate for differences in pharmacokinetics between humans and laboratory animals in exposure and risk assessments. Government scientists used this technique most recently in their risk assessment for the Teflon chemical PFOA, in which they compared measured human serum levels of PFOA to animal serum PFOA levels from laboratory studies (EPA 2005d).

In addition to the clear benefits of its use in exposure and risk assessments that shape public health policy, body burden studies are also a powerful tool for tracking the success of programs that aim to mitigate exposures. Body burden studies show, for example, that blood lead levels in children have dropped steadily since the mandatory reduction of lead in gasoline and house paint of the 1970s; the median concentration fell 85 percent between 1976 and 2000 (EPA 2003a, Pirkle et al. 1994).

Body burden data also has the capacity to uncover sensitive or highly exposed subpopulations, and the potential to elucidate distributions of exposure for individuals and across populations, including exposures to mixtures. Consideration of both of these factors — sensitive subpopulations and the nature of mixtures that comprise the human body burden — are critical components in developing effective public health policies. It is with a goal of exploring these two factors that we conducted our cord blood pollution investigation. Our study seeks specifically to measure the human body burden in an inherently sensitive in utero population, and to define in part the chemical mixtures present among the study samples.

The scientific community also uses biomonitoring such as that performed in this cord blood study to track exposure reductions that can stem from public health interventions. Biomonitoring studies have documented the success of public health interventions in dramatically reducing children's blood lead levels in the U.S. (Pirkle et al. 1994); in lowering PCB and organochlorine pesticide levels in breast milk from mothers in Germany and Sweden (Schade and Heinzow 1998, Noren and Meironyte 2000); and even in reducing exposures to second-hand smoke in the U.S. (CDC 2003).

In future biomonitoring efforts (CDC 2005) scientists from the Centers for Disease Control and Prevention plan to collect exposure data that can document the efficacy of recent public health interventions restricting the use of the Scotchgard chemical PFOS (EPA 2000d) and the popular home insecticide chlorpyrifos, or Dursban. And in the Children's Health Act of 2000 (Public Law 106-310 Sec. 1004), Congress authorized "a national longitudinal study of environmental influences (including physical, chemical, biological and psychosocial) on children's health and development." The study, as planned, aims to track exposure and health outcomes for 100,000 American children from early pregnancy to age 21 (DHHS 2004).

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More From Body Burden — The Pollution in Newborns
Executive Summary
Babies are Vulnerable
Human Health Problems on the Rise
Guide to testing.
Adult Blood Test Results.
Why are babies born polluted?
Guest Commentary
Peer Statement