Effect of heavy metals on tissue glycogen levels in the freshwater mussel, Lamellidens corrianus (Lea)

Abstract

Industrial effluents including heavy metals that enter the aquatic environment cause serious metabolic, physiological, as well as structural impairments to living organisms. In the present study, variations in gill and hepatopancreas glycogen levels in the freshwater mussel, Lamellidens conianus, exposed to different concentrations of copper, mercury, and cadmium are reported. Sampling was done on mussels exposed to 100, 200, and 400 ppb of copper, 75, 150, and 300 ppb of mercury, and 150, 300, and 600 ppb of cadmium at 24, 72, 120, and 168 h. When compared with the controls, gill glycogen levels were found depleted in copper-exposed mussels at all time-periods in all exposures, while in those exposed to mercury, depletion was more pronounced at later periods of exposure. In mussels exposed to cadmium, reduction in glycogen levels was more evident at the highest concentration. Hepatopancreas also showed a general trend of depleted levels of glycogen activity in all the exposures to all the three heavy metals. It is indicated that hypoxic conditions prevailing in mussels exposed to the heavy metals might have resulted in enhanced breakdown of glycogen.