Risk Assessment of Arsenic in Wheat and Maize Grown in Organic Matter Amended Soils of Indo-Gangetic Plain of Bihar, India

Abstract

ABSTRACT Recent outbreak of geogenic arsenic (As) contamination in the Gangetic Delta basin of Bihar drew due attention of researchers as prolonged consumption of As-contaminated drinking water and food leads to arsenicosis, with the symptoms of pigmentation and keratosis in human. Although some information on As content in rice grain grown on contaminated soil is available specific to some areas of Bihar, practically no such information is available on wheat and maize crops. The present field experiment was conducted to evaluate the efficacy of organic amendments in reducing the availability of As in contaminated soils, followed by its uptake by wheat and maize. Accumulation of total As in wheat and maize grains varied from 0.02 to 0.11 mg kg−1 and from 0.23 to 0.29 mg kg−1, respectively, whereas available As in post-harvest soil varied from 1.07 to 1.33 mg kg−1 for wheat and from 1.10 to 1.24 mg kg−1 for maize. The organic amendments reduced the As accumulation in wheat grain to the extent of 84% (sugarcane bagasse (SB)), 50% (rice straw) and 40% (paddy husk (PH)) compared with control. Similarly, As content in maize grain was the lowest in SB-treated soil followed by rice straw and PH. Solubility-free ion activity model, based on pH, organic carbon and Olsen extractable As, was effective in predicting the As uptake by wheat and maize grains to the extent of 75% and 87%, respectively. Impact of organics in reducing health hazard for intake of As through consumption of wheat and maize grains grown on contaminated soil was also reflected in the values of the corresponding hazard quotient (HQ).