Evaluation of processes controlling the geochemical constituents in deep groundwater in Bangladesh: spatial variability on arsenic and boron enrichment.
Evaluation of processes controlling the geochemical constituents in deep groundwater in Bangladesh: spatial variability on arsenic and boron enrichment.
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DOI：
10.1016/j.jhazmat.2010.01.008
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发表时间：
2010-08
影响因子：
13.6
通讯作者：
M. Halim;R. Majumder;S. A. Nessa;Y. Hiroshiro;K. Sasaki;B. Saha;A. Saepuloh;K. Jinno
中科院分区：
文献类型：
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作者：
M. Halim;R. Majumder;S. A. Nessa;Y. Hiroshiro;K. Sasaki;B. Saha;A. Saepuloh;K. Jinno
为了评价控制深层含水层系统中地球化学成分的过程，对孟加拉国高砷影响地区的46个深层地下水样本进行了分析。溶质的空间变化趋势、地球化学模拟和主成分分析表明，碳酸盐溶蚀、硅酸盐风化和离子交换控制了主要的离子化学性质。地下水以Na-Cl型微咸水为主。约17%的地下水砷含量高于饮用水可接受的最大限度10μg/L。铁与溶解有机碳（DOC）和菱铁矿正饱和指数呈强相关（R2=0.67），表明有机质存在下，铁-氢氧化铁的还原溶解被认为是深层含水层释放高含量铁（中位数0.31mg/L）的主导过程。相反，As与Fe和DOC不相关。26%的样品中硼的浓度超过了人类饮用水500μg/L的标准限值。B/Cl比与Cl呈负相关，硼与Na/Ca呈负相关，说明深部地下水中的硼伴随着微咸水和粘土沉积物中的阳离子交换。
Forty-six deep groundwater samples from highly arsenic affected areas in Bangladesh were analyzed in order to evaluate the processes controlling geochemical constituents in the deep aquifer system. Spatial trends of solutes, geochemical modeling and principal component analysis indicate that carbonate dissolution, silicate weathering and ion exchange control the major-ion chemistry. The groundwater is dominantly of Na–Cl type brackish water. Approximately 17% of the examined groundwaters exhibit As concentrations higher than the maximum acceptable limit of 10μg/L for drinking water. Strong correlation (R2=0.67) of Fe with dissolved organic carbon (DOC) and positive saturation index of siderite suggests that the reductive dissolution of Fe-oxyhydroxide in presence of organic matter is considered to be the dominant process to release high content of Fe (median 0.31mg/L) in the deep aquifer. In contrast, As is not correlated with Fe and DOC. Boron concentration in the 26% samples exceeds the standard limit of 500μg/L, for water intended for human consumption. Negative relationships of B/Cl ratio with Cl and boron with Na/Ca ratio demonstrate the boron in deep groundwater is accompanied by brackish water and cation exchange within the clayey sediments.