Hydrochemistry of groundwater with special reference to arsenic in Lakhimpur Kheri district, Uttar Pradesh, India

Abstract

The present study aims to understand the severity of Arsenic contamination along with the hydrochemistry of ground water in Lakhimpur Kheri, one of the largest districts in Uttar Pradesh, India. Ground water samples collected from 102 handpumps from 15 blocks were analyzed for physicochemical parameters and Arsenic. The groundwater quality data were analysed statistically. The characteristic features of groundwater indicated the presence of As (0-0.224 mg/L), Fe (0.011-8.634mg/L), Na + (2.84-62.12 mg/L), K + (1.21-51.20 mg/L), Ca 2+ (6-102mg/L), Mg mg/L), SO 4 2-(1-269.92 mg/L), NO 3 -(0.11-2.61 mg/L) and HCO 3 -(122-549 mg/L). The pH of the groundwater was found to be neutral to slightly alkaline (6.88-8.45) with high EC (471-1569 S/cm) and TDS (289-1042 mg/L). Of the total samples analysed, 41.18% contained As > 10g/L, 13.73% contained As < 10g/L, while in the rest of the samples As was found to be below detectable limit. Severe As contamination was reported mainly in six blocks of the study area-Pallia, Nighasan, Dhawahara, Ramia Beher, Isanagar and Nakaha. The highly contaminated block was Pallia where all the samples contained As above permissible limit. Ho wever, maximum As concentration (0.224 mg/L) was reported from a deep well handpump of village Dubha from Nighasan block. Both Shallow and deep bore handpumps were analysed to study the distribution pattern of As with depth. No systematic relationship was found. Arsenic showed insignificant correlation with EC, TDS, TH, Ca 2+ , Mg 2+ , Na + , K + , HCO 3 -, NO 3 -Cl -and SO 4