Effect of environmental contaminants on the health of Mytilus edulis from Puget Sound, Washington, USA. I. Cytochemical measures of lysosomal responses in the digestive cells using automatic image analysis

Lysosomal responses in the digestive cells of Mytilus eduljs from 9 sites in Puget Sound, Washington. USA, with varying degrees of sediment contamination were measured using automatic image analysis. Mussels from urban-associated sltes (areas with elevated sediment concentration of anthropogenic contaminants such as PAHs, PCBs. DDTs, and toxic elements) showed pathological changes in the lysosomes (reduced lysosomal labilization period, reduced lysosomal stability and increased N-acetyl P-hexosaminidase activity), enhanced lipofuscin deposition and increased accumu-lat~on of lysosomal and cytoplasmic unsaturated neutral lipids. Morphometric measures of growth showed that mussels were generally smaller in size and that somatic tissue weight relative to shell length was lower in mussels from urban-associated sites relative to those from minimally contaminated sites. Highly significant correlations were observed between concentrations of tissue PAH, PCB, and selected toxic elements (measures of anthropogenic exposure) and lysosomal labil~zation period. Pathological alterations in the lysosomal system of mussels from the urban-associated sites were probably induced by the high tissue concentrations of organic and inorganic contaminants rather than as a result of potential confounding biotic (spawning stress) or abiotic (temperature, salinity and food availability) factors. The results show that cytochemical measurement of lysosomal responses combined with automatic image analysis have the potential to be used as sensitive, accurate and rapid techniques for assessing the biological impact of environmental contaminants in mussels in the near coastal environment.