Concentration of heavy metals in groundwater and heavy metal pollution index in Punjab

Abstract

Groundwater samples (263 number) were collected from the Punjab state during August, September, and October, 2019 and were analyzed for heavy metals arsenic (As), aluminium (Al), iron (Fe), manganese (Mn), zinc (Zn), copper (Cu), chromium (Cr), cadmium (Cd), nickel (Ni), and lead (Pb). It has been found that majority of the samples have concentrations within the acceptable limits as prescribed by Indian drinking water standards. The analysed data was used for calculating heavy metal pollution index (HPI) for groundwater and mean HPI was 4.9 which are well below the critical index limit of 100. On the basis of values of HPI, all samples were classified under 3 categories as low, medium and high for corresponding HPI values of <15, 15-30 and > 30, respectively. It was found that 2 samples have values > 30, 4 samples have HPI values in the range of 15-30 and all other samples have values < 15. The study based on HPI values demonstrated that heavy metal concentrations evidently indicates the groundwater of Punjab in majority of the area monitored, to be free from heavy metal pollution and can be used for human consumption. Groundwater in the areas where HPI index is > 15 may be avoided for drinking purposes and continuous monitoring is essential to check the heavy metal pollution.