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Lookup NU author(s): Professor David WernerORCiD
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© 2022 Elsevier B.V.Irrigation activities can cause strong geochemical and hydrological fluctuations in the unsaturated zone, and affect arsenic (As) migration and transformation. The As geochemical cycle in the unsaturated zone is coupled with that of iron minerals through sorption-desorption, coprecipitation and redox processes. Dynamic batch experiments and wetting-drying cycling column experiments were conducted to evaluate As mobilization behaviors under the effects of exogenous substances, redox condition and intermittent flow. Our results show that As release under exogenous substances carried by irrigation (e.g., phosphate, carbonate, fulvic acid, humic acid, etc.) followed three trends with the types of exogenous inputs. Inorganic anions and organic matter resulted in opposite trends of arsenate release in different redox conditions. In anoxic environments, As(V) release was favored by the addition of phosphate and carbonate, while in oxic environments, the mobilization of As(V) was promoted by the addition of fulvic acid (FA). Further, intermittent irrigation promoted the reductive dissolution of Fe oxides and the mobilization of As. The addition of humic acid (HA) resulted in the mobilization of arsenate as As-Fe-HA ternary complexes. The mechanism of arsenic mobilization under irrigation has importance for prevention of arsenic exposure through soil to food chain transfer in typical high arsenic farmland.
Author(s): Cai D, Kong S, Shao Y, Liu J, Liu R, Wei X, Bai B, Werner D, Gao X, Li C
Publication type: Article
Publication status: Published
Journal: Journal of Hazardous Materials
Print publication date: 15/10/2022
Online publication date: 08/08/2022
Acceptance date: 07/08/2022
ISSN (print): 0304-3894
ISSN (electronic): 1873-3336
Publisher: Elsevier B.V.
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