CORRELATION BETWEEN BIOASSAY-DERIVED P4501A1 INDUCTION ACTIVITY AND CHEMICAL-ANALYSIS OF CLAM (LATERNULA-ELLIPTICA) EXTRACTS FROM MCMURDO SOUND, ANTARCTICA

Variable levels of halogenated aromatic hydrocarbons were measured in clams (Laternula elliptica) collected from McMurdo Sound, Antarctica. Clams collected in and near Winter Quarters Bay contained high levels of organochlorine compounds, particularly polychlorinated biphenyls (P CBs). A strong gradient has been documented in Winter Quarters Bay tha t been linked to human activities at McMurdo Station. The activity of clam extracts as inducers of P4501A1-dependent ethoxyresorufin O-deeth ylase (EROD) activity was determined using in vitro bioassays utilizin g rat hepatoma H4IIE cells. The extracts which exhibited the highest i nduction activities were those derived from clams collected in contami nated areas. Additionally, there was an excellent linear correlation b etween induced EROD activity versus total PCB levels (r2=0.96) The com plimentary nature of both the analytical and bioanalytical data confir ms the utility of the latter assay and provides a method for estimatin g the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalents in extracts from marine biota.