Heavy metal indicator potential of the asiatic clam (Corbicula fluminea) in artificial stream systems

The potential of the Asiatic clam, Corbicula fluminea , as a bioindicator of cadmium, copper, and zinc was studied during 28-day exposure in field artificial streams receiving river water on a once-through basis. Copper, at aquatic concentrations of 0.016 and 0.057 mg l super(-1), showed the greatest degree of tissue uptake and had bioconcentration factors (BCF) of 22,571 and 17,720, respectively. A significant correlation was observed between water concentrations and tissue accumulation. Cadmium was intermediate relative to BCF, and had a correlation coefficient of 0.758. Zinc had the lowest potential for concentration with a correlation coefficient of 0.478. The rate of accumulation in Corbicula reached a maximum after 11 days for cadmium while a steady state condition for copper was not observed in 28 days. Zinc accumulation, like copper, showed a relative increase throughout the 28-day exposure period. Data from this study show that the Asiatic clam may be a reliable indicator of uptake for exposure to selected heavy metals.