Lipofuscin as physiological indicator of heavy metal stress in Sunetta scripta (yellow clam) and Perna viridis (green mussel)

Sublethal exposure to copper induces enhanced total carotenoid concentration synchronous with increased lipofuscin accumulation at 48 h of exposure in Sunetta scripta and Perna viridis. The carotenoid concentration increment was found to be more in P. viridis (nearly 95% higher than control). In both the species, the control exhibits fewer number of lipofuscin granules scattered in the cytoplasm with less pigmentation, also non-aggregate in nature. Whereas at 48 h of exposure, more pigmentation with increased granular number and aggregation has been noticed. In P. viridis, the granular size remains unaltered for control and exposed cells whereas in S. scripta, an increase in granular size has been noticed at 48 h of exposure.