Abstract

Objective: To evaluate the presence of heavy metal cadmium in six species of shellfish at Pulicat Lake, Tamil Nadu, India. Methods: Six species of shellfish, Fenneropenaeus indicus, Fenneropenaeus monodon, Fenneropenaeus semisulcatus, Scylla serrata, Clibanarius longitarsus and Meretrix casta (M. casta) in Pulicat lake, Tamil Nadu, India were analysed for the presence of cadmium in the gills and muscles from January 2011 to December 2012. Results: The results showed seasonal variations in the uptake of cadmium. Very high accumulation of cadmium was found in the gills and muscles of M. casta during post monsoon, summer, premonsoon and monsoon. The corresponding values of cadmium present in the gills of M. casta were 1.59, 1.56, 1.48 and 1.46 µg/g in 2011 and 1.16, 1.25, 1.15 and 1.14 µg/g in 2012. Whereas for muscles, they were 1.14, 0.11, 0.96 and 0.80 µg/g in 2011 and 0.49, 0.34, 1.05 and 1.20 µg/g in 2012. Conclusion: The results of the present study has shown that the accumulation of cadmium found in the gills and muscles were high in M. casta when compared to other species of shellfish. Thus, the consumption of the shellfish is safe, but does not exclude bioaccumulation risk in their meat. This present study has highlighted the need for estuarine biomonitoring to avoid possible contamination of shellfish and its consumers. The overall scenario of the shellfish accumulating high levels of cadmium indicates that the Pulicat lake is polluted with undesirable elements and the risk of consuming the meat of shellfish by man and other carnivores may lead to their toxicity. Stringent control measures are necessary to control the pollution of this precious lake to reduce the bioaccumulation of toxic metals in organisms.

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