COMPARATIVE BIOACCUMULATION OF CHLORINATED HYDROCARBONS FROM SEDIMENTBY 2 INFAUNAL INVERTEBRATES

Bioaccumulation of chlorinated hydrocarbons (CHs) from field-contamina ted sediments by two infaunal invertebrates, Rhepoxynius abronius (a n on-deposit feeding amphipod) and Armandia brevis (a nonselective, depo sit-feeding polychaete), was examined and species responses were compa red. Sediments were selected over a large geographical area of the Kud son-Raritan estuary to assess the potential for bioaccumulation from a typical urban estuary. Unlike polycyclic aromatic hydrocarbons (PAHs) from these sediments, concentrations of CHs in interstitial water (IW ) indicated that partition coefficients (K-oc) were generally as expec ted, especially when based on predicted, nonsorbed, interstitial water CH concentrations (IWfree). Correlations between amphipod and polycha ete tissue residues revealed that these species were responding simila rly to a gradient of CH concentrations in sediment. While tissue resid ues and BAF(loc) (lipid/organic carbon normalized bioaccumulation fact or) values for the trichlorobiphenyls were similar for both species, a ccumulation in the polychaete was three to 10 times higher for the mor e hydrophobic PCBs, which was attributed to differences in the route o f exposure. A negative correlation between the bioaccumulation factor (BAF) and total organic carbon (TOC) was found for both species, which was expected according to equilibrium partitioning theory. Because it was assumed that the amphipod was not feeding in these tests and the polychaete was ingesting sediment, comparison of their tissue residues and bioaccumulation factors was useful for highlighting the importanc e of sediment ingestion, especially for shea-term, nonequilibrium expo sures. These results may also help elucidate the limitations associate d with assessing bioaccumulation and the resultant toxic response in s tandard 10-day toxicity tests with similar invertebrates.