title: Effects of alternating wetting and drying versus continuous flooding on chromium fate in paddy soils.
abstract: Anthropogenic chromium (Cr) pollution in soils poses a great threat to human health through the food chain. It is imperative to understand Cr fate under the range of conditions suitable for rice growth. In this study, the effects of irrigation managements on dynamics of porewater Cr(VI) concentrations in rice paddies and Cr distribution in rice were investigated with pot experiments under greenhouse conditions. Soil redox potential in continuous flooding (CF) treatments showed that reducing conditions remained for the whole duration of rice growing period, while soil redox potential in alternating wetting and drying (AWD) treatments showed that soil conditions alternately changed between reducing and oxic. As soil redox potential is an important factor affecting Cr(VI) reduction in paddy soils, dynamics of Cr(VI) concentration were clearly different under different irrigation managements. In CF treatments, porewater Cr(VI) concentrations decreased with time after planting, while in AWD treatments porewater Cr(VI) concentrations were increased and decreased alternately response to the irrigation cycles. Chromium(VI) concentrations in the CF treatments were lower than those in AWD treatments for most part of rice-growing season. Moreover, Cr concentrations in rice tissues were significantly influenced by irrigation with relatively higher values in the AWD treatments, which might be attributed to the higher porewater Cr(VI) concentrations in AWD treatments. Therefore, it would be better to use CF than AWD management in Cr-contaminated paddy soils to reduce Cr accumulation in rice, and thus to reduce the potential risk to human health.
authors.affiliation: Zhejiang Province Key Lab for Food Safety, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China. Electronic address: wendanxiao@aliyun.com.
authors.forename: Wendan
authors.initials: W
authors.lastname: Xiao
authors.affiliation: Zhejiang Province Key Lab for Food Safety, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
authors.forename: Xuezhu
authors.initials: X
authors.lastname: Ye
authors.affiliation: Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
authors.forename: Xiaoe
authors.initials: X
authors.lastname: Yang
authors.affiliation: Ministry of Education Key Laboratory of Environmental Remediation and Ecological Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310058, China.
authors.forename: Tingqiang
authors.initials: T
authors.lastname: Li
authors.affiliation: Zhejiang Province Key Lab for Food Safety, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
authors.forename: Shouping
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Zhejiang Province Key Lab for Food Safety, Institute of Quality and Standard for Agro-products, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D057914:Agricultural Irrigation; D018533:Biomass; D002857:Chromium / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D055868:Floods; D012275:Oryza / Q000254:growth & development / Q000378:metabolism*; D010084:Oxidation-Reduction; D012987:Soil / Q000737:chemistry; D012989:Soil Pollutants / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism
chemical_list: D012987:Soil; D012989:Soil Pollutants; D002857:Chromium
keywords: Alternating wetting and drying; Chromium(VI) concentration; Continuous flooding; Oryza sativa L.; Soil redox potential