Arsenic in irrigated water, soil, and rice: perspective of the cropping seasons

Abstract

Arsenic contamination of shallow groundwater and related health problems are threats for the millions in endemic regions of West Bengal. Contamination of rice grain creates the food chain pathway of mineral arsenic besides drinking water contamination. Present study concentrated on association of arsenic concentration in irrigated water, paddy field soil and rice with the cropping seasons. Irrigated ground water arsenic concentration decreased significantly (p = 0.007) from summer (median 0.42 mg l−1) to winter (median 0.35 mg l−1). Carried over effect created significant decrease (p = 0.03) of paddy field soil arsenic concentration from summer (median 8.35 mg kg−1) to winter (median 6.17 mg kg−1). Seasonal variation was observed in rice straw (p = 0.03) but not in husk (p = 0.91). Arsenic concentration decreased significantly (p = 0.05) in the rice grains collected in winter season (median 0.23 mg kg−1) than the samples collected in the summer season (median 0.30 mg kg−1). In conclusion, seasonal effects need to be considered in case of human health risk assessment from arsenic consumption.