@article{Duangthong_Damrongsiri_2021, place={Nakhon Pathom, Thailand}, title={Alteration of Fractionation and Bioavailability of Arsenic (As) in Paddy Soil under Transition from Aerobic to Anaerobic Conditions: 10.32526/ennrj/20/202100150}, volume={20}, url={https://ph02.tci-thaijo.org/index.php/ennrj/article/view/245611}, abstractNote={<p>The impact of the change from aerobic to anaerobic immersed soil conditions on arsenic (As) fractionation (Tessier’s method) and its bioavailability (ethylene diamine tetraacetic acid extractable) were assessed. As-contaminated paddy soils were tested by laboratory simulation experiments. The samples were aerobic, with 35-49 mg/kg of As at low bioavailability (<2%). Most As was distributed in the stable fraction (77%), followed by As bound to ferric and manganese oxide (17%) and organic compounds (5%), while the mobile fraction (exchangeable and mildly acid-soluble) was limited (1%). After one month under anaerobic simulation, redox potential reduced to less than zero (-32 to -124 mV)<em>.</em> The stable fraction of As decreased (-17%), while the mobile fraction increased (+16%) and As bioavailability also increased (+26% total As). Increase in the As mobile fraction was associated with freshly precipitated compounds. The As content in the soil altered from a stable fraction to an available fraction when confined in an anaerobic environment for a long period. Results indicated that agricultural methods which promoted anaerobic conditions in As-contaminated soil should be avoided.</p>}, number={1}, journal={Environment and Natural Resources Journal}, author={Duangthong, Apichaya and Damrongsiri, Seelawut}, year={2021}, month={Nov.}, pages={89–95} }