Title: The fate of arsenic in contaminated paddy soil with gypsum and ferrihydrite amendments

Authors: Xue-Ping Chen; Jingyong Zhou; Yanru Lei; Chiquan He; Xiaoyan Liu; Zheng Chen; Peng Bao

Addresses: School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China ' School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China ' School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China ' School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China ' School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444, China ' State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China ' State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China

Abstract: Ferrihydrite and gypsum (CaSO₄·2H₂O) are two chemicals which were suggested to reduce the bioavailability of arsenic (As) in agricultural field. The efficiency of those chemicals added in the paddy field was investigated by pot culture in this study. The results showed As uptake by rice under ferrihydrite treatment was significantly lower than that in the control (36% in shoot), however, plants grown in gypsum show no significant difference in As content compared with those in the control. Sequential extraction showed that As was mainly adsorbed to amorphous and crystalline hydrous oxide. The addition of gypsum did not change the As fractionation in comparison with the control, which may be due to restrained sulphur (S) reduction by the high microbially reducible Fe(III) (150-250 mg kg⁻¹), which precipitates with sulphide in preference to As. These results suggest that the chemical Fe oxides efficiently reduce As risk in the paddy.

Keywords: ferrihydrite; gypsum; arsenic; sequential extraction; soil remediation; soil contamination; environmental pollution; agricultural fields; paddy fields; rice fields; iron oxides.

DOI: 10.1504/IJEP.2014.067675

International Journal of Environment and Pollution, 2014 Vol.56 No.1/2/3/4, pp.48 - 62

Received: 23 Nov 2013
Accepted: 04 Jul 2014
Published online: 07 Mar 2015 *

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