Mobilization of arsenic in groundwater of Bangladesh: evidence from an incubation study
Mobilization of arsenic in groundwater of Bangladesh: evidence from an incubation study
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DOI：
10.1007/s10653-006-9054-0
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发表时间：
2006-12-01
影响因子：
4.2
通讯作者：
Garcia-Sanchez, A.
中科院分区：
文献类型：
--
作者：
Anawar, H. M.;Akai, J.;Garcia-Sanchez, A.
在孟加拉国许多地区，大量抽取受砷污染的地下水用于饮用、家庭和农业用途是一个严重的健康问题。本实验室为基础的孵化研究调查的来源和机制，作为动员在这些地下水。利用从孟加拉国含水层收集的沉积物进行了几项培养研究，这些沉积物补充或不补充不同的营养物质，然后分析了沉积物悬浮液的pH值、氧化还原电位、电导率以及As和Fe（II）浓度。在厌氧环境下培养的底物修饰的沉积物悬浮液中，存在As（最大值：50-67 μ g/l）和Fe（II）（最大值：182 μ g/l）的移动，而ORP值在5-6天内立即急剧下降（高达-468 mV至-560 mV）。在控制和有氧条件下培养的沉积物悬浮液中，没有发生显着的As动员。从沉积物中的As和Fe（II）的同时动员是一个强有力的迹象表明，他们的动员导致铁羟基氧化物的减少土著细菌存在于沉积物中的活性增强，这种现象也提供了见解的动员机制，作为地下水。在孵化研究中使用的沉积物中的As的浓度与氧化还原电位发展的梯度密切相关，所使用的有机营养物（葡萄糖）的量刺激。表层有机质渗透入浅层含水层可能会刺激微生物群落的活动，从而导致氢氧化铁和As释放的减少。
The extensive extraction of arsenic (As)-contaminated groundwaters for drinking, household and agricultural purposes represents a serious health concern in many districts of Bangladesh. This laboratory-based incubation study investigated the sources and mechanisms of As mobilization in these groundwaters. Several incubation studies were carried out using sediments collected from the Bangladesh aquifer that were supplemented, or not, with different nutrients, followed by an analysis of the sediment suspensions for pH, ORP (oxidation-reduction potential), EC (electrical conductivity) and As and Fe(II) concentrations. In the substrate-amended sediment suspensions incubated under anaerobic environment, there was a mobilization of As (maximum: 50-67 mu g/l) and Fe(II) (maximum: 182 mu g/l), while the ORP value decreased immediately and drastically (as much as -468 mV to -560 mV) within 5-6 days. In the sediment suspensions incubated under control and aerobic conditions, no significant As mobilization occurred. The simultaneous mobilization of As and Fe(II) from sediments is a strong indication that their mobilization resulted from the reduction of Fe oxyhydroxide by the enhanced activity of indigenous bacteria present in the sediments; this phenomenon also provides insights on the mobilization mechanism of As in groundwater. The concentrations of As in the sediments used in the incubation studies were strongly linked to the gradients of redox potential development that was stimulated by the quantity of organic nutrient (glucose) used. The penetration of surface-derived organic matter into the shallow aquifer may stimulate the activity of microbial communities, thereby leading to a reduction of iron oxyhydroxide and As release.