ISOMER-SPECIFIC ANALYSIS AND TOXIC POTENTIAL EVALUATION OF POLYCHLORINATED-BIPHENYLS IN ANTARCTIC FISH, SEABIRDS AND WEDDELL SEALS FROM TERRA-NOVA BAY (ROSS SEA)

To provide data on the degree of contamination of the marine ecosystem isomer-specific concentrations of polychlorinated biphenyls, includin g planar, mono- and di-ortho congeners, were measured in the Weddell s eal, the Adelie penguin, the south polar skua, and in two species of A ntarctic fish (Trematomus bernacchii and Chionodraco hamatus) from Ter ra Nova Bay, Antarctica. The results show a clear relation between PCB concentrations and trophic level, in the order fish < Adelie penguin < Weddell seal. The higher values found in the skua appear to be relat ed to its migration to more contaminated lower latitudes. The data for the various PCB congeners were used to calculate toxic potential in t he different animals. The 2,3,7,8-TCDD toxic equivalents of coplanar c ongeners were estimated by the ''toxic equivalent factors'' (TEFs) app roach. The highest values of TEFs were found in the south polar skua a nd Weddell seal. Values in the other species were considerably lower.