Geochemical and health risk assessment of potentially toxic trace elements and nitrate via groundwater in agro-ecosystem of alluvial plain Punjab, India

Abstract Sporadic rainfall and limited surface water sources have increased dependency on groundwater in semi-arid region of Punjab. The present paper is comprehensive study carried out in an intensive agricultural region of southwest Punjab to examine the quality and extent of contamination due to trace elements and nitrate in the aquifer system. Total 15 toxic elements are analyzed in groundwater samples (N = 129) covering both the shallow (<60 m) and deeper aquifers (>60 m). Elements such as As, B, Cd, Li, Mn, Pb, Sr, and Se exceed the prescribed limits. Overall, 68 and 13% of samples exceed the NO3 − permissible limit (45 ppm) in shallow and deep aquifers, respectively. Contaminants concentration increases toward groundwater flow direction, that is, from northeast to southwest possibly due to arid climatic conditions. Relatively, shallow aquifer is more contaminated than deeper aquifer due to fertilizers input and irrigation return flow. Drinking water quality indices (DWQI) reveal that groundwater is unfit for drinking at most locations. Further, health risk indicate that comparatively, children are at higher risk in terms of non-carcinogenic risk posed by nitrate, and higher carcinogenic risk for As, Cr, and Cd is seen in all age groups. Multivariate analysis reveals the influence of anthropogenic activities on NO3 −, Mn, Ni, and Zn levels, while geogenic factors control the, As and Mo concentrations. Present findings suggest regular monitoring of wells to lower the public health risk.