Evaluation of heavy metals in ground and surface water in Ranipet, India utilizing HPI model

Ranipet is an industrial hub located 120 km away from Chennai houses around 250 tanneries beside other industries. Tanneries and Tamil Nadu Chromate and Chemicals Limited (TCCL) generated and dumped tons of chromium waste on land and water bodies which is the major threat to the people living in the area for several years. In this study, heavy metal pollution in Ranipet industrial zone was estimated using the Heavy Metal Pollution Index (HPI) model along with spatial distribution maps. The level of Cd, Cu, Cr, Pb, Ni and Zn in ground and surface water was measured using standard methods, and the results were utilized to make the HPI model. It was observed that the metal level was in the order of Zn > Pb > Ni > Cu > Cr > Cd and Cr > Pb > Zn > Cd > Cu > Ni in ground and surface water respectively. All the ground water samples exhibited high HPI of (> 38). Except one sample with low HPI (˂ 19), and three surface water samples held in midrange (19-38), the other surface water samples displayed high HPI of (> 38). The average HPI of ground and surface water is 500.42 and 523.78. The HPI and spatial distribution of heavy metals revealed that the Cr contamination in Ranipet industrial estate is originated from the premises of TCCL.