Heavy metal concentrations in seawater and sediments of Gulf of Mannar andPalk Bay, southeast coast of India

An investigation was carried out to delineate the levels of heavy metals bo th in the seawater and sediments from the Gulf of Mannar and Palk Bay. The data, obtained during the year 1995 revealed that Cd could not be detected in the waters of Kanyakumari. However, at other stations the levels of Cd w ere in the order of Arumuganeri > Tuticorin > Thondi > Mandapam. In contras t, Pb levels were found to be maximum at Kanyakumari and minimum at Arumuga neri, while Hg was found to be maximum at Arumuganeri and minimum at Mandap am. Cd levels were found to decrease towards sea from the coast at Tuticori n. However no definite trend was observed at Mandapam and Thondi. Unlike Cd , Pb showed seaward increasing trend at Thondi transect. However, no defini te trend was evident for other transects as seen for Cd. Bottom waters show ed higher concentration of Cd and Pb as compared to those in surface water. Hg did not show any trend in its distribution. Data on sediments showed th at Cd registered maximum levels at Arumuganeri (4.33 ppm) while Kanyakumari exhibited the minimum (0.4 ppm). Similarly the levels of Pb were found to be minimum (1.15 ppm) at Kanyakumari. In conclusion, among the transects st udied, Arumuganeri appeared to be polluted.