Lysosomal histochemistry in the mussel Mytilus edulis from south-west Iceland

It has been recently highlighted that high levels of micropollutants (i.e. organometals, POPs and PAHs) may be present in the coastal waters at high latitudes, stressing the need to evaluate the effects of contamination on marine organisms from the sub-artic zones. With this aim, specimens of the blue mussels Mytilus edulis were sampled in polluted and reference areas of the southwest Iceland in July 2004. In particular, samplings were carried out intertidally in three sites of the Reykyjavik harbour differently exposed to contaminants, and in three reference locations of the Reykjaness Peninsula and Hvalfjordur fiord. Lipofuscin content, neutral lipid accumulation and lysosomal to cytoplasm volume ratio were evaluated in digestive cell cytoplasm from cryostat sections of the epatopancreas of ten mussels per each sites, and quantified through automatic image analyses. The mussels from the site in Reykyjavik harbour most influenced by extensive shipping activity (the nearest to the dock) showed highest values in lipofuscin, neutral lipid, and lysosomal to cytoplasm volume ratio. Another two sites of the harbour revealed lower levels, similar to those observed in mussels collected in the reference sites of Hvalfjordur fiord and bay of Osar, whereas mussels from Kuagerði showed the lowest values. These results are discussed in relation to their potential use as signals of coastal pollution.