Does Living near a Superfund Site Contribute to Higher Polychlorinated Biphenyl (PCB) Exposure?

We assessed determinants of cord serum polychlorinated biphenyl (PCB) levels among 720 infants born between 1993 and 1998 to mothers living near a PCB-contaminated Superfund site in Massachusetts, measuring the sum of 51 PCB congeners ($\Sigma PCB$) and ascertaining maternal address, diet, sociodemographics, and exposure risk factors. Addresses were geocoded to obtain distance to the Superfund site and neighborhood characteristics. We modeled $log_{10}(\Sigma PCB)$ as a function of potential individual and neighborhood risk factors, mapping model residuals to assess spatial correlates of PCB exposure. Similar analyses were performed for light (mono-tetra) and heavy (penta-deca) PCBs to assess potential differences in exposure pathways as a function of relative volatility. PCB-118 (relatively prevalent in site sediments and cord serum) was assessed separately. The geometric mean of $\Sigma PCB$ levels was 0.40 (range, 0.068-18.14) ng/g serum. Maternal age and birthplace were the strongest predictors of $\Sigma PCB$ levels. Maternal consumption of organ meat and local dairy products was associated with higher and smoking and previous lactation with lower $\Sigma PCB$ levels. Infants born later in the study had lower $\Sigma PCB$ levels, likely due to temporal declines in exposure and site remediation in 1994-1995. No association was found between $\Sigma PCB$ levels and residential distance from the Superfund site. Similar results were found with light and heavy PCBs and PCB-118. Previously reported demographic (age) and other (lactation, smoking, diet) correlates of PCB exposure, as well as local factors (consumption of local dairy products and Superfund site dredging) but not residential proximity to the site, were important determinants of cord serum PCB levels in the study community.