title: Effects of water management on arsenic and cadmium speciation and accumulation in an upland rice cultivar.
abstract: Pot and field experiments were conducted to investigate the effects of water regimes on the speciation and accumulation of arsenic (As) and cadmium (Cd) in Brazilian upland rice growing in soils polluted with both As and Cd. In the pot experiment constant and intermittent flooding treatments gave 3-16 times higher As concentrations in soil solution than did aerobic conditions but Cd showed the opposite trend. Compared to arsenate, there were more marked changes in the arsenite concentrations in the soil solution as water management shifted, and therefore arsenite concentrations dominated the As speciation and bioavailability in the soil. In the field experiment As concentrations in the rice grains increased from 0.14 to 0.21 mg/kg while Cd concentrations decreased from 0.21 to 0.02 mg/kg with increasing irrigation ranging from aerobic to constantly flooding conditions. Among the various water regimes the conventional irrigation treatment produced the highest rice grain yield of 6.29 tons/ha. The As speciation analysis reveals that the accumulation of dimethylarsinic acid (from 11.3% to 61.7%) made a greater contribution to the increase in total As in brown rice in the intermittent and constant flooding treatments compared to the intermittent-aerobic treatment. Thus, water management exerted opposite effects on Cd and As speciation and bioavailability in the soil and consequently on their accumulation in the upland rice. Special care is required when irrigation regime methods are employed to mitigate the accumulation of metal(loid)s in the grain of rice grown in soils polluted with both As and Cd.
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address: pjhu@issas.ac.cn.
authors.forename: Pengjie
authors.initials: P
authors.lastname: Hu
authors.affiliation: Chinese National Rice Research Institute, Hangzhou 310006, China.
authors.forename: Younan
authors.initials: Y
authors.lastname: Ouyang
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address: lhwu@issas.ac.cn.
authors.forename: Longhua
authors.initials: L
authors.lastname: Wu
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Libo
authors.initials: L
authors.lastname: Shen
authors.affiliation: Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China.
authors.forename: Yongming
authors.initials: Y
authors.lastname: Luo
authors.affiliation: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
authors.forename: Peter
authors.initials: P
authors.lastname: Christie
mesh_terms: D001151:Arsenic / Q000032:analysis / Q000378:metabolism*; D018053:Arsenites / Q000378:metabolism; D002104:Cadmium / Q000032:analysis / Q000378:metabolism*; D002681:China; D002851:Chromatography, High Pressure Liquid; D013058:Mass Spectrometry; D012275:Oryza / Q000378:metabolism*; D012989:Soil Pollutants / Q000032:analysis / Q000378:metabolism*; D013054:Spectrophotometry, Atomic; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*; D018508:Water Purification
chemical_list: D018053:Arsenites; D012989:Soil Pollutants; D014874:Water Pollutants, Chemical; D002104:Cadmium; C015001:arsenite; D001151:Arsenic
keywords: Arsenic; Cadmium; Dimethylarsinic acid (DMA); Rice; Speciation; Water management