Evaluation of groundwater quality and human health risks from fluoride and nitrate in semi-arid region of northern India

Abstract

Groundwater quality in the alluvial plains of Punjab has special significance and needs great attention since it is the foremost source of drinking, irrigation and industrial uses. The present research work emphasizes the integrated hydrogeochemical and chemometric statistical approaches to appraise the geochemical processes and source apportionment of the groundwater in the alluvial plains of Jalandhar district, Punjab, India. The human health risk assessment was also performed to quantify the potential non-carcinogenic impacts of nitrate and fluoride on human health through ingestion of groundwater. For this purpose, 41 groundwater samples were collected from different groundwater abstraction units and analysed for pH, electrical conductivity, total dissolved solids, total hardness, total alkalinity and major ions (Ca²⁺, Mg²⁺, Na⁺, K⁺, HCO₃^-, CO₃^2-, SO₄^2-, NO₃^-, F^-, Cl^- and PO₄^3-) using standard protocols. Drinking water quality index and Revelle index showed that groundwater samples fall under poor to unfit water class and salinization along the south-western portion of the study region shows poor water quality. The results of the hazard index (HI_ingestion) show 68% and 46.34% of the groundwater samples have HI > 1 for children and adults. The non-carcinogenic health risk assessment of nitrate (NO₃^-) and fluoride (F^-) on the local population indicated that the children are more vulnerable through direct ingestion of drinking water than adults. Piper diagram and saturation index reveal that Ca²⁺-Mg²⁺-HCO₃^- is the dominant hydrochemical facies and oversaturated with calcite, dolomite and aragonite minerals in the groundwater. Gibbs diagrams, chloro-alkaline indices and scatter plots show that the hydrochemistry of the groundwater is mainly governed by aquifer material interaction such as weathering of silicate, carbonate rock, halite dissolution and cation exchange process. Chemometric statistical techniques revealed that the source identification of parameters such as Ca²⁺, Mg²⁺, Na⁺, K⁺, HCO₃^-, CO₃^- and F^- is originated from geogenic factors, whereas NO₃^-, SO₄^2-, Cl^- and PO₄^3- are from the anthropogenic origin. Therefore, urgent and efficient measures must be taken to combat groundwater pollution and reduce human health risk in the study area.

Keywords: Alluvial plains; Chemometric statistical techniques; Groundwater quality; Hazard index; Hydrogeochemical.