engleski

Comparison of metal accumulation, intracellular metal distribution and metal-binding biomolecules in the digestive gland of two freshwater bivalve species from the Mrežnica River

Metals are common pollutants in aquatic systems, but they are also crucial for normal functioning of organisms. Freshwater bivalves, as filter- feeders, are suitable bioindicators of metal contamination but their accumulation capacity and intracellular distribution may vary by species. Therefore, the aim of this study was to compare the bioaccumulation and intracellular distribution of nine selected metals/metalloids (essential: Cu, Zn, Fe, Co, Mo and Se ; non-essential: Cd, Ag and As) in the digestive gland of two freshwater bivalve species, Anodonta anatina and Unio pictorum, collected from a reference site on the Mrežnica River (Croatia). Higher total metal concentrations were found in U. pictorum for all of the elements studied, except for Ag where concentrations were comparable in both species. The largest differences were found for Cd being 13 times higher, and for Co and Fe with about 3.5 fold increased values in U. pictorum. In both species, Cd and Se were primarily accumulated in the cytosol, while Fe was found mainly in the insoluble tissue fraction. The distribution of Cd and Cu did not differ significantly between species, while for all other elements except As, a significantly higher presence in the cytosolic fraction was found in A. anatina. Analysis of metal distribution among cytosolic biomolecules by size exclusion HPLC allowed the definition of molecular masses of biomolecules involved in binding of particular metals. The obtained metal profiles were comparable in both of the studied species for all of the studied elements. Our results will contribute to a better understanding of accumulation and metal metabolism in the studied freshwater bivalve species.

bioaccumulation ; bivalves ; metabolism ; metal profiles ; proteins

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