Monitoring Trace Metal Contaminants in Green Mussel, Perna viridis from the Coastal Waters of Karnataka, Southwest Coast of India

The green mussel (Perna viridis) is widely distributed in the coastal waters of Asia and is used in mussel watch programmes for monitoring environmental contaminants throughout the region. Green mussels representing different size groups and habitats were sampled from their natural beds at 28 locations in the inshore waters of Karnataka (southwest coast of India) to analyze the tissue concentrations of Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn. Tissue concentrations of Cr, Cu, Fe, and Pb were significantly higher in smaller mussels than in the larger size group. Significantly higher concentrations of Cr, Cu, Fe, Mn, and Ni were observed in mussels sampled from intertidal beds when compared to mussels from the subtidal beds. The sampling sites were categorized into industrial sites (IS), urban sites (US), and nonurban sites (NS) based on principal component analysis of metal concentrations in mussel. Spatial variations in tissue concentrations of all metals were observed except for Zn. Generally, the levels of toxic trace metals like Pb, Cd, Ni, and Cr in the whole tissue of P. viridis were within safe limits throughout the coast of Karnataka. However, relatively high concentrations of Cd, Cr, and Pb were observed in the whole tissue of green mussels collected from the industrial sites (IS), which may be derived from a variety of anthropogenic activities.