摘要:
通过分析赣南大余地区农田土壤As、Cd元素化学形态含量 ,研究土壤中As、Cd元素形态含量特征和垂向变化、全量与形态含量的相关性.研究表明 ,赣南大余地区农田生态系统中土壤残渣态As、离子交换态Cd含量分别为22 .14 mg/kg和0 .437 mg/kg ,分别占其总量的76 .88% 和54 .97% ;异常区表层土壤As、Cd元素的活动态百分比含量分别为4 .03% 和70 .29% ,分别高出对照区1 .55倍和0 .61倍 ;受污灌或洪水漫淹的农田土壤中As、Cd元素活动态含量具有垂直分布特征 ,其在0~20 cm的表层土壤中富集显著 ,而20 cm之下的土层含量有不同程度的下降.随表层土壤As、Cd元素总量增加 ,残渣态As和离子交换态Cd的百分比含量增加 ,而其它形态的百分含量下降或无显著变化.
Abstract:
Content ,vertical exchange ,correlation of total content and speciation content were deter-mined by geochemical speciation analysis of As and Cd in farmland soil in Dayu County ,Jiangxi Province . The results showed that the contents of residual As and ion exchange Cd were 22 .14 mg/kg and 0 .437 mg/kg ,which accounted for 76 .88% and 54 .97% ,respectively .The percentage of mobile As and Cd in abnormal topsoil were 4 .03% and 70 .29% ,1 .55 and 0 .61 times higher than that of the controlled areas , respectively .The contents of As and Cd in the farmland soil affected by sewage irrigation or flood had the characteristics of vertical distribution existed as significant enrichment in topsoil of 0~20 cm ,varying de-grees of decline under 20 cm .With the increasing of As and Cd in topsoil ,the percentage content of the re-sidual As and ion exchange Cd increased ,w hile the other speciation contents decreased or with no signifi-cant changing .
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