Polychlorinated biphenyls, organochlorine pesticides and trace metals in cultured and harvested bivalves from the eastern Adriatic coast (Croatia)

•PCBs, organochlorine pesticides, and trace metals were determined in bivalves.•Spatial and seasonal distribution was dependent on the origin of contaminants.•No significant differences in organic contaminant levels were found among species.•Significant differences in Cu and Zn levels were found among species.•Contaminant levels pose no harmful risk to bivalve consumers.

Polychlorinated biphenyls, organochlorine pesticides and trace metals were determined in tissues of bivalve molluscs (Mytilus galloprovincialis, Ostrea edulis, Venus verrucosa, Arca noae and Callista chione), collected from 11 harvesting and 2 cultured locations along the eastern Adriatic coast, in May and November 2012. Concentrations (ng g−1 dry weight) of organochlorines ranged from 1.53 to 21.1 for PCBs and 0.68 to 5.21 for p,p'-DDTs. HCB, lindane, heptachlor and aldrin-like compounds were found in lower levels or were not detected. Metal concentrations (mg kg−1 dry weight) ranged from 0.23 to 4.03 for Cd, 0.87–3.43 for Cr, 3.69–202.3 for Cu, 0.06–0.26 for HgT, 0.62–9.42 for Ni, 0.95–4.64 for Pb, and 55.76–4010.3 for Zn. Established organochlorine and trace metal levels were lower than the maximum allowable levels in seafood set by the European Commission.