PAH CONTENT AND MUTAGENICITY OF MARINE-SEDIMENTS FROM THE VENICE LAGOON

Sediments from the Venice lagoon, a polluted coastal environment in no rtheastern Italy, were assayed for mutagenicity and content of several toxic microcontaminants, which included selected polycyclic aromatic hydrocarbons (PAHs); the latter are specifically dealt with in this pa per. Samples were collected at three lagoon sites with reasonably dist inct environmental features-urban, industrial, or agricultural-and at two others considered to be under mixed pollution influences; a sixth sample was obtained from an open sea area to act as background control , The organic matter (EOM) associated with the mineral substrata was e xtracted; after cleanup, analyte determination was carried out by HRGC -LRMS(SIM) using isotopically labeled compounds as internal standards. Cumulative levels of the selected PAHs were found to be in the range of 0.065 to 0.46 mu g/g of dry matrix at five sites; a much higher con centration (48 mu g/g) was detected in the sample from the urban envir onment. The remarkable PAH level increase at this site was mostly acco unted for by the concurrent, apparent increase of EOM contamination as PAH concentration was seen to reach 32 mu g/mg of EOM from <1 mu g/mg at the five remaining sites. Mutagenicity assays with Salmonella typh imurium strains TA98 and TA100 of marine sediment organic extracts als o highlighted a distinct activity in the sample from the urban site. F urther fractionation and analysis of this extract pointed to PAHs as t he main mutagenic component present in the sediment matrix, possibly a ccounting for up to approximately 70-80% of the entire mutagenic poten tial detected. (C) 1996 Academic Press, Inc.