土著微生物参与下河套平原地下水中砷的还原作用

Reduction of Arsenic in Groundwater from Hetao Plain with the Involvement of Indigenous Microbes

为查明土著微生物活动对高砷地下水形成的影响,利用河套平原高砷地下水中分离出的土著微生物(YH002)进行了微宇宙实验研究.实验结果表明:高砷地下水中加入的葡萄糖提供了微生物生长所需要的碳源,微生物大量繁殖,分泌的有机酸使溶液的pH值降低.在缺氧条件下,溶液中的OD值最高达到了0.189,pH值最低为6.22;在有氧条件下,OD值最高达到了0.286,pH值最低为6.04.溶液中As(Ⅲ)的初始质量浓度为74μg/L,占总砷质量浓度的11.2%,在加入微生物和葡萄糖后,在缺氧和有氧条件下,As(Ⅲ)的质量浓度分别为278μg/L和310μg/L,占总砷质量浓度的42%和47%.微宇宙实验说明地下水中的土著微生物能将As(V)还原成As(Ⅲ).

In order to understand the effect of microbial activities on the occurrence of high arsenic groundwater,microcosm experiments were conducted using the indigenous microbe（YH002） isolated from high arsenic groundwater collected from Hetao Plain.The experiments show that the microcosm supplemented with bacteria and glucose,bacterial metabolism can excrete the organic acid which can cause pH decline.Under anoxic conditions,the maximal OD values reached 0.189 on the 7th day and the pH reduced to 6.22.However,under oxic conditions,the maximum of OD value also occurred on the 7th day with the value of 0.286,while pH values reduced to 6.04 at the end of the experiment.The initial concentration of As（III） was 74 μg/L,accounting for 11.2% of the total arsenic,when at the presence of the microbe and glucose,As（III） concentrations were 278 μg/L and 310 μg/L,accounting for 42% and 47% of the total arsenic,in the N2 and O2 atmosphere,respectively.The experimental results show that the indigenous microbe is capable of reducing As（V） to As（III） in groundwater.