Effects of long-term paddy rice cultivation on soil arsenic speciation
Journal
Journal of Environmental Management
Journal Volume
254
Date Issued
2020
Author(s)
Abstract
Geochemical behavior of arsenic (As) in rice paddy soils determines the availability and mobility of As in the soils, but little is known about the long-term effects of paddy rice cultivation on As speciation in the soils. In this study, surface soil samples were collected from a rice paddy land and its adjacent dry land with similar soil properties and known cultivation histories. The soils of the paddy land and dry land contained 378 and 423 mg As kg−1, respectively. The predominant As species in the soils were investigated using As K-edge X-ray absorption spectroscopy (XAS) in combination with two sequential chemical fractionation methods. The XAS results showed that the predominant As species in the soils were As(III)- and As(V)-ferrihydrite, As(V)-goethite and scorodite. In comparison to the dry land soil, the paddy land soil contained a higher proportion of As(V)-ferrihydrite and a lower proportion of scorodite. The results of chemical fractionation revealed that As in the paddy land soil was more labile than that in the dry land soil. It is therefore suggested that long-term rice cultivation enhances the mobility and availability of As in paddy soils. © 2019 Elsevier Ltd
Subjects
Arsenic speciation; Paddy soil; Redox transformation; Wet-dry cycles
SDGs
Other Subjects
arsenic; ferric hydroxide; organic matter; arsenic; atomic absorption spectroscopy; chemical composition; element mobility; fractionation; paddy field; redox potential; speciation (chemistry); wetting-drying cycle; Article; chemical analysis; comparative study; controlled study; dry land; fractionation; land use; long term care; nonhuman; paddy land; rice; soil analysis; soil property; surface soil; X ray absorption spectroscopy; Oryza; soil; soil pollutant; Arsenic; Oryza; Soil; Soil Pollutants; X-Ray Absorption Spectroscopy
Type
journal article