engleski

Crowat project: Comparison of biomarkers between field-collected and caged mussels

Mussels Mytilus galloprovincialis collected at four coastal locations in the Kaštela/Trogir Bay and mussels caged for 1 month at two locations, a polluted location (Trogir Shipyard, TR-SY) in the same monitoring area and an unpolluted locations at the Šolta Island (ŠO), have been used in order to compare the biomarker response between field-collected and transplantated mussels. Two biomarkers were chosen: a biomarker specific for heavy metal exposure, the metallothionein (MT) and a non-specific biomarker of multiple stressors, the lysosomal membrane stability (LMS). MT content was determined in gill samples by a spectrophotometric method, and LSM was evaluated in mussel hemocytes using a neutral red lysosomal assay. Besides biomarkers, the heavy metals content in the heat-treated cytosolic fraction of gills and the total cytosolic proteins were determined as well as particular biometric variables (condition index, mussel and gill mass) and percent of tissue water content. Pronounced differences in MT, metal and total protein concentrations expressed on a wet tissue mass basis between native and caged mussels were obtained. These differences could be mostly explained by a higher proportion of water in the tissue of caged mussels, although the influence of some other factors affecting protein syntesis can not be entirely excluded. MT and metal data were normalized using metal(MT)/shell mass indices. Higher index values for Cu were obtained in mussels caged at more metal polluted TR-SY station. Mussels caged at ŠO station had a slightly higher Cd/shell mass index putting in the question the selection of this site as a reference location. The results will be disscused in terms of suitability of native and caged mussels for biomonitoring purposes.

biomarkers; native and caged Mytilus galloprovincialis; heavy metals

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