Superfund Research Program
A Partnership Study of the Effects of PCBs on Akwesasne Mohawk Youth
Polychlorinated biphenyls (PCBs) are a group of 209 environmentally persistent organochlorine compounds. PCB congeners are probable human carcinogens and are known or suspected to result in neurotoxicity, immunotoxicity, endocrine disruption, and growth disturbance. There are no known natural sources of PCBs and although PCBs have not been manufactured in the United States since 1977, their diminishing but continued presence in the environment and the workplace has resulted in low-level exposure to the general population. Native American communities are particularly at risk of PCB exposure as the result of their subsistence systems and cultural ethos involving greater contact with the physical environment.
Over the past 40 years, emissions from three industrial sites have contaminated the air, land, and water in and around the northern New York Akwesasne Mohawk community with toxic substances including PCBs, polycyclic aromatic hydrocarbons, dioxins, dibenzofurans, metals, cyanide, and styrene. Within 10 years of the construction of the automobile and foundry plants along the St. Lawrence River, the Mohawk community began noticing impacts on their health, livestock, and the environment.
Scientists at the University of Albany, State University of New York, are involved in a community partnership research project in collaboration with the Akwesasne Mohawk Nation. Their research goals are: (1) to identify the effects of PCB body burden on the physical growth, maturation, and cognitive development of children and youth including endocrine measures of thyroid function and sexual maturation; and (2) to identify the role of body composition, specifically fat stores, in determining the level and effect of PCBs in circulation.
Researchers have interviewed 270 sets of mother/child participants, collecting a diverse data set including information on maternal fish consumption, adolescent diets, socio-demographic data, height, weight and body composition measures, sexual maturation scale, and alcohol and cigarette use. Assessments of adolescent cognitive and behavioral characteristics were also conducted. Levels of total thyroxine, free thyroxine, triiodothyronine, and thyroid stimulating hormone were then measured in adolescents' blood.
An important part of this collaborative research effort is the intensive effort to ensure that members of the Akwesasne community from whom the data were collected are kept informed of the research progress and results. Outreach activities have included (1) sharing the results interviews, examinations, psychological assessments, and laboratory analyses with the study participants; and (2) presenting preliminary results and updates at meetings of the Akwesasne Task Force on the Environment which is responsible for study of environmental quality and connections between the environment and the health of the community.
The University of Albany scientists confirmed that PCB exposure of adolescents in this community is largely in utero or/and lactational and is most strongly related to maternal consumption of contaminated fish prior to pregnancy. Comparison of blood levels of PCBs and thyroid hormones indicate that PCBs may affect growth, development or cognitive function. Preliminary analysis of data from 117 participants in this study has found that the level of highly chlorinated congeners (PCBs with 5-9 chlorine substitutions) is significantly related to thyroid function. The researchers emphasize that because the PCB levels in the sample are very low, the results of the thyroid hormone studies may pertain to many populations with low exposure.
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To learn more about this research, please refer to the following sources:
- Gallo M, Schell LM, Newman J, DeCaprio AP, the Akwesasne Task Force on the Environment. 2000. Relationship of polychlorinated biphenyls (PCBs) in Akwesasne Mohawk Nation youth and maternal fish consumption before and during pregnancy. American Journal of Human Biology 12:266-267.
- Schell LM, DeCaprio AP, Gallo M, Hubicki L, the Akwesasne Task Force on the Environment. 2000. Polychlorinated biphenyls and thyroid function in adolescents of the Mohawk Nation at Akwesasne. In: Proceedings of IX International Congress of Auxology: Human Growth From Conception to Maturity. Turin, Italy. Smith-Gordon, London,
- Denham M, Schell LM, Choh A, Gallo M, Newman J, the Akwesasne Task Force on the Environment. 1999. Sexual maturation of Akwesasne Mohawk youth. American Journal of Human Biology 11:109.
- Schell LM, Tarbell A. 1998. A partnership study of PCBs and the health of Mohawk youth: Lessons from our past and guidelines for our future. Environ Health Perspect 106:833-840. PMID:9646046
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