DDT, DDD, AND DDE CONTAMINATION OF SEDIMENT IN THE NEWARK BAY ESTUARY, NEW-JERSEY

Two hundred and forty-six surface and buried sediment samples from Newark Bay, New Jersey, and its major tributaries (Passaic River, Hackensack River, Newark Bay, Arthur Kill, Elizabeth River, and Kill Van Kull) were assayed for p,p'-dichlorodiphenyltrichloroethane (p.p'-DDT), p,p'-dichlorodiphenyldichloroethane (p,p'-DDD), and p,p'-dichlorodiphenylchloroethylene (p,p'-DDE) between February 1990 and March 1993. Chronological profiles in sediments from pre-1940 to the present were determined by radioisotope activities of (210)pb and (CS)-C-137. The concentrations of these chemicals were compared to National Oceanic and Atmospheric Administration (NOAA) benchmark sediment values (Long and Morgan 1991). The objectives were to (a) determine the spatial and temporal distributions of DDT compounds in sediments, (b) identify possible sources, and (c) assess the potential for sediment toxicity within the estuary. Mean concentrations in surface sediments in individual waterways ranged from 5 to 473 mu g/kg for p,p'-DDT, 18 to 429 mu g/kg for p,p'-DDD, and 5 to 111 mu g/kg for p,p'-DDE. A regional background mean concentration of approximately 100-300 mu g/kg Sigma p,p'-DDT (sum of p,p'-DDT, p,p'-DDD, and p,p'-DDE) was measured in surface sediments throughout the estuary, with the exception of the Arthur Kill, where mean concentrations exceeded 700 mu g/kg. The elevated concentrations found in recently deposited surface sediments in the Arthur Kill may be due to the presence of ongoing sources. The highest concentrations in buried sediments occurred in the lower Passaic River at depths corresponding to historical deposits from 1940 to 1970, the peak time period for production and usage of DDT in the United States. Comparisons to NOAA benchmark sediment toxicity values indicate that p,p'-DDT, p,p'-DDD, and p,p'-DDE concentrations in surface sediments may pose a potential hazard to fish, shellfish, and other benthic and demersal organisms in some portions of the estuary, particularly in the upper and lower Arthur Kill.