Levels, persistence and bioavailability of organic contaminants present inmarine harbor sediments impacted by raw sewage

As part of a program to investigate the levels, fate and bioaccumulation of organic contaminants in a polluted marine harbor, organochlorine compounds including the polychlorinated biphenyls (PCBs), dichloro diphenyltrichloro ethane and metabolites (DDTs), chlordanes, dibenzo-p-dioxins (Ds) and diben zofurans (Fs), polycyclic aromatic hydrocarbons (PAHs) and sulphur hetero c ycles were analysed in sediments spiked with St. John's Harbor sludge. Wint er flounder (Pseudopleuronectes americamus) were exposed to these sediments containing six levels of harbor sludge during four winter months. Followin g exposure, sediments were reanalysed to investigate the persistence of the contaminants. The primary contaminants detected were PAHs (similar to 5000 ng/g), predominantly alkylated phenanthrenes, fluoranthene and pyrene; PCB s with a predominance of Aroclor 1260 signature (similar to 64 ng/g), DDTs (similar to 5 ng/g), hepta and octachloro dioxins and furans (similar to 0. 5 ng/g) with very row levels of less chlorinated congeners. The PAHs degrad ed with an estimated half life of 2 to 3 months, while no significant degra dation could be attributed to the other compounds. Bioaccumulation to muscl e showed the potential uptake of contaminants in biota inhabiting the harbo r. A dose-response relationship was observed between spiked sediments and t he concentrations of PCB congener 153 and unresolved congeners 138/163/164 in muscle. Of the dioxins and furans, only 2, 3, 7, 8-tetrachlorofuran was detectable in muscle and at a similar concentration in all exposures indica ting a similar bioavailability independent of the fraction of sludge in sed iments. Of the PAHs, only naphthalene and methyl naphthalenes were detected in muscle, but did not display a dose-response. One bile metabolite of pyr ene was quantified and demonstrates metabolism. Biota-sediment accumulation factors were of 0.2 to 7 indicating that equilibrium was approached, with the exception of the hepta and octachloro dioxins and furans which were not significantly bioaccumulated. (C) 1998 Elsevier Science Ltd. All rights re served.