ARSENIC CONTAMINATED GROUNDWATER AND ASSOCIATED HEALTH EFFECT IN GANGES DELTA, WEST BENGAL, INDIA

Arsenic (As) contamination in groundwater was causing widespread human health disaster around the World (especially in Southeast Asia). Our aim was to determine the degree of severity of As exposure from drinking groundwater in Lower Ganga Plain (Moyna and Adrebok regions, North 24-Parganas district, West Bengal, India). The analysis reveals that the groundwaters were mostly Ca-HCO₃ type and anoxic in nature (mean Eh = 34 mV). The groundwater contains high concentrations of As (ranged between <10 to 538 μg/L) along with high Fe (0.07 to 9.8 mg/L) and with relatively low Mn (0.15 to 3.4 mg/L). The groundwater contains mostly As(III), exhibiting reducing character, consistent with Eh values. The geochemical data supports Fe-/Mn- reduction process as the dominant pathway for As release in these groundwaters. The population-based case-reference study showed increased risk for skin lesions and As accumulation in hair and nails. High As concentrations were also observed in the urine samples. The surveyed populations were affected by chronic bronchitis including keratosis and melanosis. There were positive correlations between As content in hair, nails and urine with As content in groundwater. The accumulation of As in hair and nails were observed to be increased with age. The dermatological features of the As-affected population exhibited symptoms of keratosis and melanosis. This study further supports that regular awareness campaign was required as part of the management and prevention of such human health hazard.