HIGH BREAST-MILK LEVELS OF POLYCHLORINATED-BIPHENYLS (PCBS) AMONG 4 WOMEN LIVING ADJACENT TO A PCB-CONTAMINATED WASTE SITE

As a consequence of contamination by effluents from local electronics manufacturing facilities, the New Bedford Harbor and estuary in southe astern Massachusetts is among the sites in the United States that are considered the most highly contaminated by polychlorinated biphenyls ( PCBs). Since 1993, measures of intrauterine PCB exposure have been obt ained for a sample of New Bedford area infants. Among 122 mother-infan t pairs, we identified four milk samples with total PCB levels that we re significantly higher than the rest, with estimated total PCBs rangi ng from 1,100 to 2,400 ng/g milk fat compared with an overall mean of 320 ng/g milk fat for the 122 women. The congener profile and history of one case was consistent with past occupational PCB exposures. Other wise, the source of PCB exposures in these cases was difficult to spec ify. Environmental exposures including those from fish consumption wer e likely, whereas residence adjacent to a PCB-contaminated site was co nsidered an unlikely exposure source. In all four cases, the infants w ere full-term, healthy newborns. Because the developing nervous system is believed to be particularly susceptible to PCBs (for example, pren atal PCB exposures have been associated with prematurity, decrements i n birth weight and gestation time, and behavioral and developmental de ficits in later infancy and childhood, including decrements in IQ), it is critical to ascertain if breast-feeding is a health risk for the w omen's infants. Despite the potential for large postnatal PCB exposure s via breast milk, there is limited evidence of significant developmen tal toxicity associated with the transmission of moderate PCB concentr ations through breast milk. Breast-feeding is associated with substant ia health benefits including better cognitive skills among breast-fed compared with formula-fed infants. We conclude, based on evidence from other studies, that the benefits of breast-feeding probably outweigh any risk from PCB exposures via breast milk among the four New Bedford infants. In this case report, PCB analysis of breast milk and infant cord serum was a research tool. PCB analysis of milk is rarely done cl inically, in part because It is difficult to use the results of such a nalyses to predict health risks. Substantial effort is needed to achie ve a better understanding of the clinical and public health significan ce of PCB exposures, particularly among potentially susceptible groups such as infants and children. Such efforts are critical to improving the clinical and public heath management of widespread and ongoing pop ulation exposures to PCBs.