Groundwater quality and associated human health risk assessment in parts of Raebareli district, Uttar Pradesh, India

Groundwater is a primary drinking water source in various parts of Indo-Gangetic plain. Many rural agglomerations in this alluvial plain face scarcity of safe drinking water. Yet, there is a lack of public awareness and scientific studies in these areas, and Raebareli district is one of them. Groundwater samples collected from handpumps, dugwells, and tubewells were analysed for various physico-chemical parameters and compared with drinking standards for drinking suitability. The elevated concentrations of nitrate can be attributed towards heavy fertilizer application and irrigation practices, whereas rock-water interaction can be a cause for higher fluoride concentrations in groundwater. The ionic abundance was in order of HCO3- > Na+ > Cl- > SO42- > Mg2+ > Ca2+ > NO3- > K+ > F-, and HCO3- > Na+ > Cl- > SO42- > Ca2+ > Mg2+ > NO3- > k(+) > F- during the pre-monsoon and post-monsoon seasons respectively. Irrigation suitability of groundwater was also assessed using Sodium Absorption Ratio, Wilcox diagram, Doneen's plot, Kelley's index, Magnesium Hazard, and other suitable indices. The analysis suggested that there is a medium to high salinity hazard in the area. As per Kelley's index, approximately 57% of the samples were found unsuitable for irrigation practices. Non-carcinogenic health hazards associated with nitrate and fluoride and their impacts on adult men and children were also assessed. The 'Total Hazard Index' values ranged from 0.4 to 14.5 in children, and 0.3 to 10.8 in adult men. The results also suggested that more than 82% of the samples for children and 77% for adult men could possibly impart non-carcinogenic health hazards.