Use of the zebra mussel (Dreissena polymorpha) as a bioindicator for aromatic hydrocarbons in Hamilton Harbour

Three methods for the extraction of polycyclic aromatic hydrocarbons (PAHs) from zebra mussels (Dreissena polymorpha) sampled from Hamilton Harbour we re compared. Replicate freeze-dried mussel tissue samples were extracted us ing acid digestion, tissue homogenization (mechanical extraction) and ultra sonication. Each extract was submitted to a cleanup procedure (alumina chro matography and Sephadex LH20 gel chromatography), followed by analysis usin g gas chromatography-mass spectrometry (GC-MS). The three extraction method s were equally efficient, based on a statistical comparison of mean concent rations of individual PAHs. Mussel extracts, when subjected to bioassays wi th Salmonella typhimurium strain YG1029 (TA100-like) in the presence of an exogenous metabolic activation system (S9), exhibited significant mutagenic responses; these responses varied with the PAH content of the mussel extra cts. Sources of PAHs in mussel extracts were determined by examining the pr ofiles of sulfur-containing polycyclic aromatic compounds (thia-arenes). Co mparison of the ratios of certain thia-arenes with ratios in source samples enabled identification of vehicular emissions and coal tar-contaminated se diment as two sources of PAH contamination in Hamilton Harbour.