Journal of Hazardous Materials ( IF 13.6 ) Pub Date : 2022-08-08 , DOI: 10.1016/j.jhazmat.2022.129736 Dawei Cai 1 , Shuqiong Kong 1 , Yixian Shao 2 , Juanjuan Liu 1 , Ruiqi Liu 1 , Xiaguo Wei 1 , Bing Bai 1 , David Werner 3 , Xubo Gao 1 , Chengcheng Li 4
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.
中文翻译:
灌溉条件下含砷铁矿物中砷的迁移:外源物质、氧化还原条件和间歇流动的影响
灌溉活动会引起非饱和区强烈的地球化学和水文波动,影响砷(As)的迁移和转化。非饱和区的砷地球化学循环通过吸附-解吸、共沉淀和氧化还原过程与铁矿物的地球化学循环耦合。通过动态批次实验和干湿循环柱实验,评估了外源物质、氧化还原条件和间歇流动影响下的 As 动员行为。我们的研究结果表明,灌溉携带的外源物质(如磷酸盐、碳酸盐、黄腐酸、腐植酸等)下的As释放随外源输入类型的变化呈现三种趋势。无机阴离子和有机物导致不同氧化还原条件下砷酸盐释放的趋势相反。在缺氧环境中,添加磷酸盐和碳酸盐有利于 As(V) 的释放,而在有氧环境中,添加富里酸 (FA) 促进了 As(V) 的迁移。此外,间歇灌溉促进了 Fe 氧化物的还原溶解和 As 的迁移。添加腐植酸 (HA) 导致砷酸盐以 As-Fe-HA 三元配合物的形式移动。灌溉条件下砷的动员机制对于典型高砷农田防止砷通过土壤向食物链转移具有重要意义。添加腐植酸 (HA) 导致砷酸盐以 As-Fe-HA 三元配合物的形式移动。灌溉条件下砷的动员机制对于典型高砷农田防止砷通过土壤向食物链转移具有重要意义。添加腐植酸 (HA) 导致砷酸盐以 As-Fe-HA 三元配合物的形式移动。灌溉条件下砷的动员机制对于典型高砷农田防止砷通过土壤向食物链转移具有重要意义。