Arsenic accumulation, speciation and bioavailability in rice cultivated in arsanilic acid exposed soil

Abstract

The present study used various amounts of P-arsanilic acid (AsA) in pot experiments to evaluate the effects of AsA on arsenic (As) accumulation, speciation and meanwhile using the in vitro digestion/Caco-2 cell model to evaluate the bioavailability of As in rice. The results indicated a linear relationship between As in rice and As in soil, and at 75 mg AsA/kg of soil, As content in rice exceeded the statutory permissible limit of 0.2 mg As/kg dry weight in China. Speciation studies indicated that inorganic As (Asi), dimethylarsinic acid (DMA), and monomethylarsonic acid (MMA) were the main As species in rice. Bioavailability of As experiment indicated that As uptake and transport amount by Caco-2 cells increased with increasing As accumulation in rice. In general, the content of AsA in soil reached or exceeded 75 mg/kg, which is not suitable for growing rice.