A BIOASSAY-DIRECTED INVESTIGATION OF SYDNEY HARBOR SEDIMENT

A coal tar-contaminated sediment sample from Sydney Harbour, Nova Scotia, Canada was examined for genotoxicity using a bioassay-directed fractionation approach. An organic solvent soluble fraction, prepared from the marine sediment by ultrasonic extraction, was fractionated into compound classes using a sequential alumina and Sephadex LH20 clean-up procedure followed by high performance chromatographic techniques. The PAH-containing fractions were analyzed using gas chromatography-mass spectrometry (GC-MS) and reversed phase-high performance liquid chromatography (RP-HPLC). The composition of the fractionated material was also characterized using Salmonella typhimurium microbiological assays to identify fractions with mutagenic potency. The fraction containing the PAH was the major source of mutagenicity requiring microsomal activation. Compounds responsible for some of the mutagenic activity in the PAH-containing fraction, including benzo[a]pyrene, benzo[ghi]perylene and indeno[1,2,3-cd]pyrene, were identified through a combination of RP-HPLC followed by GC-MS of individual subfractions.