Spatial variability and concentration of arsenic in the groundwater of a region in Nadia district, West Bengal, India

Abstract

Arsenic pollution in ground water in India and Bangladesh is considered to be the largest contamination problem in the world. About 15 – 18% of the area of West Bengal, India comes under the threat of arsenic (As) contamination and around 5.36 million people are exposed to this hazard. A detailed isoline map corresponding to variations in arsenic concentration and their spatial distribution was prepared for the study area, which comprised two villages Ghentugachi and Gotera in Nadia district, West Bengal and the total area covered was 808 hectares. The pattern of arsenic contamination was highly irregular and diverse. About 11.2% of the study area was affected most ( > 0.50 mg As l−1) with sample As values reaching 0.71 and 0.80 mg l−1. About 22.5% of the area had As content between 0.20 and 0.50 mg l−1 and 33.9% of study area had As content below the WHO guideline of 0.01 mg As/l. Thus the local population living around these areas is vulnerable and exposed to arsenic contamination. None of the water samples exceeded the allowable limit (1.0 mg As l−1) of As for water used in irrigation purposes. The spatial distribution map helped to determine zones with different As concentrations, making it possible to identify high-risk zones.