Abstract

Fluoride and nitrate are the most widespread toxic pollutant elements present in groundwaters in large parts of India. The study assessed the groundwater quality and non-carcinogenic health risk due to fluoride and nitrate. Groundwaters were alkaline in reaction with the predominance of sulfate > bicarbonate > chloride > nitrate > fluoride. About 83.8% of the samples were poor in water quality and 77 and 93% of the samples had nitrate and fluoride content above the permissible limit for drinking. Principal component analysis suggested that alkaline pH of groundwater was due to presence of high bicarbonate and low calcium concentration (resulting from precipitation of calcium as calcium carbonate), that also favored release of fluoride. Cluster analysis indicated a common source of anions and cations (Na, Ca and Cl) and the influence of anthropogenic activities in groundwater nitrate contamination; but a geogenic source for fluoride and the influence of alkaline water on weathering of fluoride bearing minerals. The hazard quotient for infant, children and adults due to nitrate was 2.8, 2.19 and 2.0 and due to fluoride was 3.39, 2.64 and 2.42 respectively and 99% of the samples were above the cumulative hazard index implicating that groundwater was unsafe for drinking.

摘要

氟化物和硝酸盐是印度大部分地区地下水中最普遍的有毒污染物。该研究评估了地下水质量和氟化物和硝酸盐引起的非致癌健康风险。地下水以硫酸盐>碳酸氢盐>氯化物>硝酸盐>氟化物为主，呈碱性。大约83.8％的样品的水质较差，其中77％和93％的样品中的硝酸盐和氟化物含量超过了允许的饮用极限。主成分分析表明，地下水的碱性pH值归因于碳酸氢根含量高和钙浓度低（由于钙以碳酸钙的形式沉淀），也有利于氟化物的释放。聚类分析表明阴离子和阳离子是常见的来源（Na，钙和氯）以及人为活动对地下水硝酸盐污染的影响；但是氟化物的地源，以及碱性水对含氟化物矿物的风化的影响。硝酸盐对婴儿，儿童和成人的危害系数分别为2.8、2.19和2.0，氟化物的危害系数分别为3.39、2.64和2.42，其中99％的样品高于累积危害指数，这表明地下水不安全饮用。