Arsenic contamination in sesame and possible mitigation through organic interventions in the lower Gangetic Plain of West Bengal, India

BACKGROUND: The widespread geogenic arsenic contamination of groundwater in the Gangetic Delta of West Bengal, leading to toxicities through the food chain - principally through irrigated rice - drew due attention from researchers. Oilseeds such as sesame might be a remunerative alternative to rice and can be grown with small quantities of contaminated groundwater. RESULTS: The present study was conducted to explore the efficiency of organic matter in reducing arsenic accumulation in sesame. Accumulation of total arsenic in sesame seed and available arsenic in post-harvest soils varied from 0.08 to 0.58 mg kg(-1) and from 3.87 to 8.89 kg ha(-1), respectively. The organic manures added as soil amendment significantly reduced the accumulation (concentration) of arsenic in sesame seed to a maximum extent of 65.5% (vermicompost), 50% (phosphocompost), 42% (mustard cake) and 40% (farmyard manure (FYM)) compared with the control counterpart. The risk associated with dietary exposure to arsenic-contaminated sesame oil reached a value of 15.55% of provisional tolerable weekly intake for arsenic at the maximum accumulation of arsenic in sesame oil. CONCLUSION: Substantial accumulation of arsenic in the soil-plant system was found. Risks of exposure to arsenic-contaminated oil remained considerably high. Irrigation through surface water and organic amendments both significantly reduced arsenic accumulation in sesame. (C) 2011 Society of Chemical Industry