Seasonal variation of heavy metals in coastal water of the Coromandel coast, Bay of Bengal, India

Abstract

This report presents the dissolved heavy metals and associated hydrographic and nutrients data. Concentrations of heavy metals such as Cu, Zn, Ni, Co, Cd and Hg were showed a rather homogeneous distribution (except Hg) within the

coastal region, with high values of Cu (63.20 μg l^-1) and Cd (66 .80 μg l^-1) at Mahabalipuram and Zn (130.20 μg l^-1),Ni(14.60 μg l^-1), Co (9.60 μg l^-1) and Hg (0.12 μg l^-1) at Pondicherry during the premonsoon and monsoon seasons respectively. High concentrations of these metals in water may be due to the discharge of monsoonal rains carrying discharge of industrial and agricultural wastes and sewage directly into the coast. This is substantiated by a highly significant positive correlation between concentrations of heavy metals in seawater and nutrients. The metal concentrations in seawater were in

<span style="font-size:14.0pt;line-height:115%;font-family:" times="" new="" roman";="" mso-fareast-font-family:"times="" roman";color:black;mso-ansi-language:en-in;="" mso-fareast-language:en-in;mso-bidi-language:hi"="" lang="EN-IN">order of Zn> Cu> Cd> Ni> Co> Hg at Mahabalipuram and Zn> Cd> Cu> Co> Ni> Hg at Pondicherry. Enrichment of heavy metals contaminations were more in the Coromandel coast, when compared to other marine environs of the Indian coast and also compared to natural seawater level.</span>