Understanding Urban Groundwater Pollution in the Upper Gangetic Alluvial Plains of Northern India with Multiple Industries and Their Impact on Drinking Water Quality and Associated Health Risks

Udham Singh Nagar district is having various industries like paint, textile, sugar, petrochemical, paper and automobile which produces different kind of contaminants including heavy metals in the environment and pollute groundwater. Therefore, in the present study, fifty groundwater samples were collected from this region and analyzed for 7 physicochemical parameters (pH, electrical conductivity, total dissolved solids, bicarbonate, chloride, sulphate, nitrate), 4 metals (calcium, magnesium, sodium, potassium) along with 6 heavy metals (Fe, Mn, Zn, Pb, Cd, Cr). Heavy metal pollution level in the groundwater was assessed by calculating and analysing heavy metal pollution indices (heavy metal pollution indices -HPI, m-HPI; heavy metal evaluation index- HEI) and risk assessment parameters (hazard quotient - HQ and hazard index - HI). Multivariate statistical analysis was also done to identify the sources of heavy metals and categorize groundwater quality. Concentration of Fe, Mn and Cr in 14%, 16% and 18% water samples exceeded the desirable limit. Piper diagram suggested that majority of groundwater samples were Ca–Mg–HCO3 type. HPI calculation indicated that no groundwater sample fall under high category of pollution. HEI and m-HPI indicated that 90% and 82% groundwater samples were found suitable for potable purpose respectively while on the basis of m-HPI, 3 groundwater samples were found under the unacceptable category. Non-carcinogenic hazards were observed which might be due to high chromium content. According to principal component analysis (PCA) and cluster analysis (CA), geogenic, anthropogenic and industrial activities were responsible for groundwater pollution. The values of HQ for Cr for both adult (13 samples) and younger people (9 sampling sits) surpass the unity. HI values indicated that groundwater samples from 14 sites were not suitable for drinking purpose. This is the first attempt of analyzing heavy metal pollution and health risk in Udham Singh Nagar district of Uttarakhand.