Vulnerability of deep groundwater in the Bengal Aquifer System to contamination by arsenic
Vulnerability of deep groundwater in the Bengal Aquifer System to contamination by arsenic
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DOI：
10.1038/ngeo750
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发表时间：
2010-02-01
影响因子：
18.3
通讯作者：
Ahmed, K. M.
中科院分区：
文献类型：
--
作者：
Burgess, W. G.;Hoque, M. A.;Ahmed, K. M.
浅层地下水是孟加拉盆地的主要水源，其砷含量高达世界卫生组织（世卫组织）饮用水标准10 μ g（-1）的100倍，威胁着7000万人的健康。深度超过150米的地下水几乎一致符合世卫组织的准则，已成为首选的替代水源。深井易受砷污染的程度取决于诱导地下水流道的几何形状以及浅层和深层之间所遇到的地球化学条件。在某些地区，水流分层将深层地下水与浅层砷源分开。氧化沉积物还通过铁氧氢氧化物吸附砷的能力来保护深层地下水。盆地尺度的地下水流动模型表明，在大范围地区，用于家庭供应的深手抽井可能在数百年内不会受到砷的入侵。相比之下，广泛的深层灌溉抽水可能会在几十年内有效地消除深层地下水作为一种无砷资源。需要更精细的模型，包括空间异质性，来研究深度城市抽象在特定城市位置的安全性。
Shallow groundwater, the primary water source in the Bengal Basin, contains up to 100 times the World Health Organization (WHO) drinking-water guideline of 10 mu g l(-1) arsenic (As), threatening the health of 70 million people. Groundwater from a depth greater than 150 m, which almost uniformly meets the WHO guideline, has become the preferred alternative source. The vulnerability of deep wells to contamination by As is governed by the geometry of induced groundwater flow paths and the geochemical conditions encountered between the shallow and deep regions of the aquifer. Stratification of flow separates deep groundwater from shallow sources of As in some areas. Oxidized sediments also protect deep groundwater through the ability of ferric oxyhydroxides to adsorb As. Basin-scale groundwater flow modelling suggests that, over large regions, deep hand-pumped wells for domestic supply may be secure against As invasion for hundreds of years. By contrast, widespread deep irrigation pumping might effectively eliminate deep groundwater as an As-free resource within decades. Finer-scale models, incorporating spatial heterogeneity, are needed to investigate the security of deep municipal abstraction at specific urban locations.