Susan Korrick

Date: December 13, 2005

Developmental Health Effects of PCBs in a Superfund Community

New Bedford Harbor in southeastern Massachusetts is a well-characterized polychlorinated biphenyl (PCB)-contaminated Superfund site as a consequence of pollution from local electronics manufacturing. Concerns about potential increased exposure risk, and related health hazards, among area residents have been ongoing. Children with early life exposures are believed to be particularly sensitive to PCB-associated health hazards. However, PCB-associated risks of adverse child development have been inconsistently demonstrated in epidemiologic studies.

In an effort to better understand the developmental health effects of early life PCB exposure, 788 newborns (born between 1993-98) residing in communities adjacent to the New Bedford waste site were recruited. Prenatal organochlorine (PCBs, DDE, and hexachlorobenzene) measures were obtained on the children at birth and they had developmental assessments beginning at birth through age 8 years. Retention of this sociodemographically diverse cohort has been excellent with approximately 80% participation in the 8-year follow-up. Cord serum PCB levels in the study population were low with mean (SD) sum PCB of 0.54 (0.83) ng/g serum, approximately 25-50% of levels observed in most other longitudinal studies of PCB exposure and child development.

Despite low-level exposure, local factors including the relative predominance of the dioxin-like PCB congener 118 in site sediments, maternal consumption of locally grown foods, and the U.S. EPA’s dredging of the harbor site during study recruitment were predictive of cord serum PCB levels. Small negative associations were observed for PCBs and birth weight with evidence of effect modification by sociodemographic and maternal factors. E.g., the steepest cord serum PCB-associated declines in birth weight were observed among infants whose mothers smoked during pregnancy.

Higher prenatal PCB exposures were also associated with poorer neuromuscular maturity, including hypo-reflexia, on newborn exam. Study children’s 8-year assessments are ongoing. Global cognitive measures such as 8-year IQ were not associated with prenatal PCB exposure in this population. However, our preliminary 8-year findings are notable for evidence of prenatal PCB exposure-associated: (1) increased risk of behavioral disorders, particularly Attention Deficit Hyperactivity Disorder (ADHD)-associated behaviors; (2) decrements in verbal proficiency; and (3) impaired memory.

These behavioral and cognitive outcomes measure skills related to the risk of childhood behavioral and learning disorders, increasingly common sources of childhood and later life morbidity and public health concern. Our findings contribute to an improved understanding of the children’s health risks associated with early life exposure to low-level PCBs as well as the potential PCB exposure risks associated with residence in communities adjacent to PCB-contaminated sites.

^*This work was made possible by grant number P42-ES05947 from the National Institute of Environmental Health Sciences, NIH. Its contents are solely the responsibility of the author(s) and do not necessarily represent the official views of NIEHS, NIH.

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