Use of the Zebra Mussel (Dreissena polymorpha) as a Bioindicator for Aromatic Hydrocarbons in Hamilton Harbour

Abstract Three methods for the extraction of polycyclic aromatic hydrocarbons (PAHs) from zebra mussels (Dreissena polymorpha) sampled from Hamilton Harbour were compared. Replicate freeze-dried mussel tissue samples were extracted using 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 using gas chromatography-mass spectrometry (GC-MS). The three extraction methods were equally efficient, based on a statistical comparison of mean concentrations of individual PAHs. Mussel extracts, when subjected to bioassays with 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 extracts. Sources of PAHs in mussel extracts were determined by examining the profiles of sulfur-containing polycyclic aromatic compounds (thia-arenes). Comparison of the ratios of certain thia-arenes with ratios in source samples enabled identification of vehicular emissions and coal tar-contaminated sediment as two sources of PAH contamination in Hamilton Harbour.