Wang Zhao, Cui Jiang-Hui, Chen Zheng, Lu Xiu-Jun, Liu Wen-Ju
College of Recourses and Environmental Sciences, Agricultural University of Hebei, Baoding 071000, Hebei, China.
Ying Yong Sheng Tai Xue Bao. 2013 May;24(5):1415-22.
Taking arsenic (As)-contaminated paddy soil as test object, and by using high performance liquid chromatography inductively coupled plasma-mass spectrometry (HPLC-ICP-MS), this paper studied the variations of As species in soil solution when the soil was sterilized or non-sterilized and incubated at different temperatures (5, 27, and 50 degrees C) under flooding. In the soil solution (pore water), only As(III) (arsenite), As(V) (arsenate), and DMA(V) ( dimethylarsinic acid) were detected, but no MMA(V)(mono methylarsinic acid) was found. With the increasing time of flooding and at the test temperatures, arsenite became the predominant species, averagely accounting for 64%, followed by As(V), with the proportion of 35%, and DMA(V), with the least proportion of 1%. Soil sterilization or non-sterilization had less effect on the concentrations of As(III) and DMA(V) in the soil solution, but remarkably affected the reduction of As(V) and the methylation of As(III). The promotion effect of soil sterilization decreased gradually with the increasing time of flooding and incubation. At 50 degrees C and after flooded for 23 days, the DMA(V) concentration in sterilized soil solution was the highest and up to 23.7 ng x mL(-1), indicating that some thermophilic microbes remained in sterilized soil became predominant species, and promoted the methylation of As(III) In sum, the total arsenic concentration in non-sterilized soil at incubation temperature 27 degrees C and flooded for 23 days was relatively low (501 ng x mL(-1)), and thus, in As-contaminated paddy rice planting areas, to adopt the water management mode of short cycle flooding-non-flooding could decrease the As level in soil solution as far as possible, and in the same time, save water resources and ensure yielding.
以受砷（As）污染的稻田土壤为试验对象，采用高效液相色谱-电感耦合等离子体质谱联用仪（HPLC-ICP-MS），研究了在淹水条件下，土壤经过灭菌或未灭菌处理，并在不同温度（5、27和50℃）下培养时，土壤溶液中砷形态的变化。在土壤溶液（孔隙水）中，仅检测到As(III)（亚砷酸盐）、As(V)（砷酸盐）和DMA(V)（二甲基砷酸），未发现MMA(V)（一甲基砷酸）。随着淹水时间的延长以及在试验温度下，亚砷酸盐成为主要形态，平均占64%，其次是As(V)，占比35%，DMA(V)占比最少，为1%。土壤灭菌或未灭菌对土壤溶液中As(III)和DMA(V)的浓度影响较小，但对As(V)的还原和As(III)的甲基化有显著影响。土壤灭菌的促进作用随着淹水和培养时间的增加而逐渐降低。在50℃且淹水23天后，灭菌土壤溶液中DMA(V)浓度最高，达23.7 ng x mL(-1)，表明灭菌土壤中残留的一些嗜热微生物成为优势菌种，促进了As(III)的甲基化。总之，在27℃培养温度下淹水23天的未灭菌土壤中总砷浓度相对较低（501 ng x mL(-1)），因此，在受砷污染的水稻种植区，采用短周期淹水-落干的水分管理模式可尽可能降低土壤溶液中的砷含量，同时节约水资源并保证产量。
