Effect of transplantation on heavy metal concentrations in commercial clams of Lake Timsah, Suez Canal, Egypt
Treść / Zawartość
Ruditapes decussatus and Venerupis pullastra are commercially fished clams with a wide distribution in the shallow inshore waters of Lake Timsah, Egypt. They are usually contaminated with heavy metals. Consumption of such contaminated clams can pose a public health risk. To minimize this risk, therefore, the clams should be removed from the contaminated waters and transferred to an approved area to reduce the high levels of metals before being marketed. The aim of this work was to study the effect of transplantation on levels of heavy metals (Fe, Mn, Zn, Cu,Ni, Co,Cd,Pb) in these clams. The clams were removed from their polluted site and transplanted to a relatively clean area for a period of 120 days. Although the salinity at the transplantation site was higher than at the polluted site, it was stable and did not appear to have any adverse effect on clam growth. Heavy metals were analysed in the water, sediment and clam tissues from both the polluted and the transplantation sites. Although in both species transplantation evidently reduced heavy metal levels, these still exceeded the maximum permissible levels laid down by the WHO (1982).