Assessment of Heavy Metal Accumulation and Mineralization in Edible Bivalves and Their Health Risks: A Case Study of Timsah Lake, Suez Canal, Egypt

Abstract

The heavy metals were measured in edible parts and shells of five edible bivalve species; Venerupis corrugata, Venerupis sp., Venerupis aurea, Ruditapes decussatus, and Paratapes undulatus collected from Timsah Lake, Suez Canal, Egypt. Ruditapes decussatus showed the highest average of flesh weight and exhibited the highest accumulation averages of Mn, Ni, and Pb. Paratapes undulatus recorded the highest averages of Fe, Zn, Cu, Cd, and Co in their flesh. According to the WHO guidelines, Fe levels in the edible parts of V. corrugata, R. decussatus and P. undulatus exceed the permissible limit of 100 µg/g. In contrast, Cu and Zn metals concentrations are below the permissible limits of 30 and 1000 µg/g, respectively. The levels of Pb and Ni surpass the permissible limits (0.2 and 0.35 µg/g) in all the studied species. Meanwhile, Cd levels are below the permissible limit (0.07 µg/g) in all species, except for P. undulatus. Furthermore, P. undulatus had the highest shell weight average and the highest averages of the mineralized; Fe, Mn, Zn, Cu, Ni, Pb, and Cd. Zn recorded the highest mineralization ratio (metal _shell/metal _flesh) in the shells of R. decussatus, P. undulates, and V. corrugata (11.38, 6.26, and 5.18, respectively). However, Cd and Fe showed high mineralization ratios in the shell lattices of P. undulatus (7.17, 6.22), suggesting that some bivalve species have demonstrated differential abilities to mineralize certain metals within their shells.