POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS IN MYA-ARENARIA IN THE NEWARK RARITAN-BAY ESTUARY

The objectives of this study were to examine the bioavailability, bioaccumulation, and elimination of several polychlorinated dibenzo-p-dioxins and dibenzofurans in the soft-shell clam, Mya arenaria Linneaus. Clams were collected from three sites in the Newark/Raritan Bay estuary (Newark, NJ; Elizabeth, NJ; Wards Point, NY), from Little Egg Harbor (Tuckerton, NJ), and from the Chesapeake Bay (Prince Frederick, MD). Collections were made between 1986 and 1990, and samples were prepared for isomer-specific analysis. Clams from the Newark site contained TCDD concentrations that ranged from 11 to 20 parts per trillion (pptr), from the Elizabeth site 4.8 to 10 pptr, and from Wards Point 0.5 to 1.1 pptr. Clams collected from Tuckerton and Chesapeake Bay ranged from 0.1 to 0.6 pptr. Transplantation of clams from Chesapeake Bay into the Elizabeth site resulted in bioaccumulation of dioxins and furans to concentrations comparable with the natural Elizabeth population by three months post-transplant. Transplantation of soft-shell clams from the Elizabeth into the Tucker-ton site resulted in elimination of dioxins and furans to concentrations comparable with the natural Tuckerton population within four months post-transplant. The calculated half-life of elimination for TCDD was 45 d, for TCDF 111 d, and for I-TEF 66 d.