奎屯河及玛纳斯河流域平原区地下水中氮素对砷迁移富集的影响

发布时间：2018-11-27 09:57

【摘要】：研究奎屯河及玛纳斯河流域氮素对地下水中As浓度的影响,可以深入了解研究区高砷地下水的迁移富集机理.通过对奎屯河和玛纳斯河流域的34个地下水样品的采集和测试,分析了研究区地下水的水化学成分以及地下水中硝酸盐、氨氮与砷浓度之间的关系,并探讨了地下水系统中氧化还原环境对砷迁移富集的影响.结果表明,奎屯河和玛纳斯河流域高砷地下水水化学类型分别主要为SO_4·HCO_3-Na和HCO_3·SO_4-Na型.研究区高砷地下水赋存于低Eh和NO_3~-,高NH_4~+/NT、Fe、Mn的还原性环境中,在水平上主要分布于流域的地下水排泄区、湖积平原处,奎屯河流域地下水样中砷浓度都超标且明显高于玛纳斯河流域;在垂直方向上,主要集中在80—200 m.地下水中砷浓度和NO_3~-浓度呈负相关关系,这是因为在由NO_3~-指示的处于氧化环境的地下水系统中,铁锰化合物未被还原,因此其吸附的砷的化合物也没有释放.地下水中砷浓度随着NH_4~+/NT增大而增大,NH_4~+/NT可以指示地下水系统的还原环境的强弱程度,NH_4~+/N_T越大,地下水系统还原环境越强,含砷化合物越容易产生还原性溶解,将其吸附的砷释放到地下水中,且五价砷被还原成三价砷.
[Abstract]:To study the effect of nitrogen on the concentration of As in groundwater in Kuitun and Manas River basins, the migration and enrichment mechanism of high-arsenic groundwater in the study area can be deeply understood. Based on the sampling and testing of 34 groundwater samples from the Kuitun and Manas River basins, the chemical composition of groundwater and the relationship between nitrate, ammonia nitrogen and arsenic concentration in groundwater in the study area were analyzed. The effect of redox environment on arsenic migration and enrichment in groundwater system was also discussed. The results show that the hydrochemical types of high arsenic groundwater in Kuitun River and Manas River basin are mainly SO_4 HCO_3-Na and HCO_3 SO_4-Na type respectively. The groundwater with high arsenic in the study area is located in the reductive environment of low Eh and NO_3~-, high NH_4~ / NT,Fe,Mn, and distributes mainly in the drainage area of the basin and the lake plain at the level. The concentration of arsenic in groundwater samples in Kuitun River Basin was higher than that in Manas River Basin. In the vertical direction, it is mainly concentrated in 80-200 m. There is a negative correlation between arsenic concentration in groundwater and NO_3~- concentration because iron and manganese compounds have not been reduced in the groundwater system indicated by NO_3~- in oxidized environment and therefore the arsenic compounds adsorbed by them have not been released. The concentration of arsenic in groundwater increases with the increase of NH_4~ / NT. NH_4~ / NT can indicate the degree of reduction environment of groundwater system. The larger the NH_4~ / NSCT, the stronger the reduction environment of groundwater system. Arsenic compounds are more likely to cause reductive dissolution and release the adsorbed arsenic into groundwater, and the pentavalent arsenic is reduced to trivalent arsenic.
【作者单位】：新疆农业大学水利与土木工程学院;新疆水文水资源工程技术研究中心;
【基金】：新疆维吾尔自治区自然科学基金青年基金(2016D01B024)资助~~
【分类号】：X523

【相似文献】