Geochemical aspects of Meretrix casta (bivalve) shells of Vellar estuary, southeast coast of India

The bivalve mollusk, Meretrix casta shells are abundant in the Vellar estuary along the East coast of India, they are economically important and used as chief raw material for many lime based industries. Their shells are harvested in large quantities for meat and lime production. The present study focused on understanding the chemical characteristics of M. casta shells, collected at eight different locations in the marine zone of Vellar estuary. Slica, alumina, iron, calcium and magnesium were determined by wet analysis method. The concentrations of Cu, Fe, Zn, Cd, Hg and Mg were analysed by inductive coupled plasma - optical emission spectroscopy (ICP-OES). The M. casta shells consists of calcium which is up to 54%, silica, aluminum, iron and magnesium constituents are very small. Metal concentrations in the shells were in the following order: Fe>Mg>Zn>Cu. The results of heavy metal concentrations was Fe (1.822 mg/l), Mg (0.420 mg/l), Zn (0.026mg/l) and Cu (0.017 mg/l), the elements Cd and Hg were below detection limit in all the eight locations. The result evidenced that the shells were suitable for industrial applications especially for lime based industries. Key words: Raw materials, bivalve, Meretrix casta , ICP-OES, heavy metals, Vellar estuary. African Journal of Biotechnology , Vol 13(19), 2090-2094