Effect of Organic and Inorganic Amendments on Uptake of Arsenic by Wheat and Transformations of Arsenic in a Contaminated Soil

Abstract

Arsenic (As) poisoning to humans through the consumption of food grown on contaminated soil becomes a major issue. We, therefore, experimented to study the effect of selected organic and inorganic amendments to restrict the availability of As in contaminated soil of the Indo Gangetic Plain of Bihar and its uptake by wheat crop. Available As in post-harvest non-spiked and spiked soil and As content in wheat grain were reduced by the application of sugarcane bagasse, press mud, poultry manure, and red mud. The As concentrations in different soil fractions were determined. Among these soil fractions, only non-specifically sorbed and specifically sorbed bounded-As contributed significantly to plant uptake. Solubility-free ion activity model, based on pH, organic carbon and Olsen extractable As, was effective in predicting As uptake by wheat grains in both non-spiked and spiked soil, accounting for 89% and 87% of the variation, respectively. To assess the risk to human health posed by arsenic intake through consumption of wheat grain grown in contaminated soil treated with different amendments, we calculated hazard quotients (HQ), which ranged from 0.233 to 0.335 for non-spiked soil and 0.321 to 0.403 for spiked soil. Overall, study concluded that availability of As can be reduced significantly through application of organic and inorganic amendments in contaminated soils for growing crops to safe use of human consumption.