title: Assessing the labile arsenic pool in contaminated paddy soils by isotopic dilution techniques and simple extractions.
abstract: Arsenic (As) contamination of paddy soils threatens rice cultivation and the health of populations relying on rice as a staple crop. In the present study, isotopic dilution techniques were used to determine the chemically labile (E value) and phytoavailable (L value) pools of As in a range of paddy soils from Bangladesh, India, and China and two arable soils from the UK varying in the degree and sources of As contamination. The E value accounted for 6.2-21.4% of the total As, suggesting that a large proportion of soil As is chemically nonlabile. L values measured with rice grown under anaerobic conditions were generally larger than those under aerobic conditions, indicating increased potentially phytoavailable pool of As in flooded soils. In an incubation study, As was mobilized into soil pore water mainly as arsenite under flooded conditions, with Bangladeshi soils contaminated by irrigation of groundwater showing a greater potential of As mobilization than other soils. Arsenic mobilization was best predicted by phosphate-extractable As in the soils.
authors.affiliation: Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK.
authors.forename: Jacqueline L
authors.initials: JL
authors.lastname: Stroud
authors.forename: M Asaduzzman
authors.initials: MA
authors.lastname: Khan
authors.forename: Gareth J
authors.initials: GJ
authors.lastname: Norton
authors.forename: M Rafiqul
authors.initials: MR
authors.lastname: Islam
authors.forename: Tapash
authors.initials: T
authors.lastname: Dasgupta
authors.forename: Yong-Guan
authors.initials: YG
authors.lastname: Zhu
authors.forename: Adam H
authors.initials: AH
authors.lastname: Price
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Meharg
authors.forename: Steve P
authors.initials: SP
authors.lastname: McGrath
authors.forename: Fang-Jie
authors.initials: FJ
authors.lastname: Zhao
mesh_terms: D000383:Agriculture; D001151:Arsenic / Q000032:analysis* / Q000737:chemistry; D005591:Chemical Fractionation / Q000379:methods; D004784:Environmental Monitoring / Q000379:methods*; D005618:Fresh Water / Q000737:chemistry; D007554:Isotopes / Q000032:analysis / Q000737:chemistry; D012275:Oryza; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis* / Q000737:chemistry
chemical_list: D007554:Isotopes; D012987:Soil; D012989:Soil Pollutants; D001151:Arsenic