Bioavailability, risk assessment, and source traceability of potentially toxic elements in bivalve species widely consumed in the emblematic Acapulco Bay, Mexico

The concentration of potentially toxic elements (PTE) was determined in edible tissue, digestive system, and shells of two bivalve species ( Hyotissa hyotis and Spondylus limbatus ) highly consumed in Acapulco Bay (southern Mexico) to evaluate the impact on marine ecosystems and human health risk associated with the consumption of potentially contaminated bivalves. PTE concentrations (Ba-Cd-Cu-Co-Cr-Mn-Ni-Pb-Sr-V-Zn) in edible tissues were lower than in the digestive system and shells in both bivalve species. Except for Cr, Pb, and Cd, PTE concentrations in the edible tissue of both species did not exceed international threshold limits. In addition, the biota-sediment accumulation factor values indicate bioaccumulation in edible tissues (Ni, Cd, Pb, Co, and Zn), digestive system (V, Ni, Cu, Cd, Pb, Co, and Zn), and shells (V, Cr, Pb, Co, and Mn), evidencing availability of pollutants in the Acapulco Bay. Contents of Pb and Cd found in edible tissue can threaten human health. Target Hazard Quotient values indicate that the consumption of edible tissue does not represent any risk of developing non-cancerogenic effects. However, the Target Cancer Risk values indicate a moderate risk of developing carcinogenic effects due to the accumulation of Cr and Pb and an even greater risk due to the accumulation of Cd. Additionally, although local rocks and sediments should be the only source of PTE in uncontaminated marine ecosystems, a low radiogenic Pb isotope composition was detected in the bivalve shells, which partially overlap with Pb isotope compositions of paints and gasoline, indicating anthropogenic lead sources participation in the Acapulco Bay.