Open AccessAlteration of Fractionation and Bioavailability of Arsenic (As) in Paddy Soil under Transition from Aerobic to Anaerobic Conditions
Author(s) -
Apichaya Duangthong,
Seelawut Damrongsiri
Publication year - 2021
Publication title -
environment and natural resources journal/warasan singwaetlom lae sappayakon tammachat
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.202
H-Index - 5
eISSN - 2408-2384
pISSN - 1686-5456
DOI - 10.32526/ennrj/20/202100150
Subject(s) - bioavailability , fractionation , arsenic , chemistry , environmental chemistry , fraction (chemistry) , anaerobic exercise , ferric , chromatography , inorganic chemistry , biology , organic chemistry , physiology , bioinformatics
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). 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.