The concentration of seven eco-toxic heavy metals such as As, Mn, Zn, Cd, Cr, Cu and Pb have been analyzed for 50 ground water sampling stations in and around Gulf of Mannar (GoM) and Palk strait (PS) sea shore area by atomic absorption spectrometer. The concentrations of heavy metals have been found to above the permissible limit of drinking water quality standards. The data have been used for the calculation of Heavy-metal Pollution Index (HPI) and Metal Index (MI). The mean HPI values of ground water in GoM and Palk Strait area are 233.2 and 136.4 respectively. The results indicated that mean HPI values were found to be above the critical pollution index value of 100. Mean deviation and percentage deviation from the mean HPI value was also calculated for each sampling point. HPI results showed that, 60% of the sampling sites at Gulf of Mannar were found higher than the critical pollution index 100, however, in Palk Strait 68% of the sampling sites showed higher than the critical pollution index. The comparative study of these two study areas were also carried out and represented in the form of bar diagram. The mean MI values of ground water at GoM and Palk Strait area are 1.728 and 0.589 respectively. These results of MI were used to ascertain the heavy metal toxicity among the sampling sites.
Keywords: Heavy Metal Pollution Index; Metal Index; Gulf of Mannar; Palk Strait;