Tracing recharge to aquifers beneath an Asian megacity with Cl/Br and stable isotopes: the example of Dhaka, Bangladesh
Tracing recharge to aquifers beneath an Asian megacity with Cl/Br and stable isotopes: the example of Dhaka, Bangladesh
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DOI：
10.1007/s10040-014-1155-8
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发表时间：
2014-06
影响因子：
2.8
通讯作者：
M. A. Hoque;J. McArthur;P. K. Sikdar;J. D. Ball;T. Molla
中科院分区：
文献类型：
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作者：
M. A. Hoque;J. McArthur;P. K. Sikdar;J. D. Ball;T. Molla
孟加拉国首都达卡有1500万人口，85%的供水来自城市地下含水层的地下水。在达卡西部以下距河流3公里的地下水中，以及城市周围和城市内的河流和下水道中，氯/溴和氯值500是常见的。研究表明，达卡西部以下的地下水受到渗漏的下水道和未铺设下水道的卫生设施的渗入以及图拉格-布里甘加河系的河岸渗入的强烈影响，图拉格-布里甘加河系是达卡西部边界的边界。达卡周围其他河流的河岸渗透作用很小。氯/溴和氯浓度值显示，在达卡采样的井中，23%的井受到高达1%的盐水的影响。这种残留的天然盐度影响了利用地下水的电导率作为确定受污染地表水的补给途径的方法。地下水样品中As、B、BA、Cd、Cu、F、Ni、NO3、Pb、Sb、Se和U的浓度低于世卫组织基于健康的饮用水指导值。
Dhaka, the capital of Bangladesh, is home to a population of 15 million people, whose water supply is 85% drawn from groundwater in aquifers that underlie the city. Values of Cl/Br> 500 are common in groundwater beneath western Dhaka in areas< 3 km from the river, and in rivers and sewers around and within the city. The study shows that groundwater beneath western Dhaka is strongly influenced by infiltration of effluent from leaking sewers and unsewered sanitation, and by river-bank infiltration from the Turag-Buriganga river system which bounds the western limit of the city. River-bank infiltration from other rivers around Dhaka is minor. Values of Cl/Br and Cl concentrations reveal that 23% of wells sampled in Dhaka are influenced by saline connate water in amounts up to 1%. This residual natural salinity compromises the use of electrical conductivity of groundwater as a method for defining pathways of recharge by contaminated surface waters. Concentrations of As, B, Ba, Cd, Cu, F, Ni, NO 3, Pb, Sb, Se and U in groundwater samples are less than WHO health-based guideline values for drinking water.