Polychlorinated biphenyls in Narragansett Bay surface sediments

Polychlorinated biphenyls (PCBs) were evaluated in 41 surface sediments collected from Narragansett Bay, RI in 1997–1998. Highest concentrations of total PCBs (1760 ng/g) were in rivers at the head of the bay and the values decreased southward toward the mouth of the bay, with elevated concentrations in some of the coves. The PCB levels in not, vert, similar43% of the samples exceeded the effects range median (ERM) guideline [Environ. Manage. 19 (1995) 81] indicating possible adverse biological effects at these stations.Principal component analysis (PCA) of the surface sediment PCBs separated the Taunton River samples from the rest of the samples. This result suggests that this river has a different PCB composition and sources than the other areas investigated. It also showed that this river has a limited influence on other bay stations as the adjacent samples downstream did not have the same chemical signature. Congener ratios derived from the PCA were useful in distinguishing stations that had different sources of PCBs than the bulk of the bay sediments. Although Aroclor 1268 and 1270 accounted for <1% of all PCB production, their major components, CB206 and CB209, account for 3–6% of the CBs in most bay samples. This may reflect more local use of these Aroclor mixtures and/or be indicative of their relative stability, compared to less chlorinated mixtures.Principal component analysis (PCA) of the surface sediment PCBs separated the Taunton River samples from the rest of the samples. This result suggests that this river has a different PCB composition and sources than the other areas investigated. It also showed that this river has a limited influence on other bay stations as the adjacent samples downstream did not have the same chemical signature. Congener ratios derived from the PCA were useful in distinguishing stations that had different sources of PCBs than the bulk of the bay sediments. Although Aroclor 1268 and 1270 accounted for <1% of all PCB production, their major components, CB206 and CB209, account for 3–6% of the CBs in most bay samples. This may reflect more local use of these Aroclor mixtures and/or be indicative of their relative stability, compared to less chlorinated mixtures.