Arsenic in shallow groundwater of Bangladesh: investigations from three different physiographic settings
Arsenic in shallow groundwater of Bangladesh: investigations from three different physiographic settings
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DOI：
10.1007/s10040-007-0203-z
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发表时间：
2007-12-01
影响因子：
2.8
通讯作者：
Jacks, Gunnar
中科院分区：
文献类型：
--
作者：
Hasan, M. Aziz;Ahmed, K. Matin;Jacks, Gunnar
孟加拉国孟加拉盆地砷的赋存状态与沉积环境和沉积物结构密切相关。不同的自然地理和沉积历史的三个网站的水化学数据显示氧化还原状态和溶解As浓度的显着变化。砷浓度在地下水中的恒河泛滥平原（GFP）的特点是低，其中高锰浓度表明通过还原锰（IV）-羟基氧化物的氧化还原缓冲。低DOC，HCO 3-，NH 4+和高NO3-和SO（4）（2-）浓度反映了GFP含水层的氧化还原状态升高。相比之下，在恒河三角洲平原（GDP）的砷浓度是非常高的沿着与高铁和低锰。在Meghna洪泛平原（MFP），中度到高的As和Fe的浓度和低锰检测。有机质的降解可能会驱动含水层中的氧化还原反应，特别是在MFP和GDP，从而动员溶解的As。形态计算表明相对于菱铁矿和蓝铁矿在MFP和GDP的地下水样品中的过饱和，但在GFP威尔斯井地下水一般是过饱和菱锰矿。MFP和GDP站点的log P-CO2值通常高于GFP站点。与MFP和GDP位点的Fe（III）-氧化还原缓冲相比，这与GFP位点提出的Mn（IV）-氧化还原缓冲一致。
Occurrences of arsenic (As) in the Bengal Basin of Bangladesh show close relationships with depositional environments and sediment textures. Hydrochemical data from three sites with varying physiography and sedimentation history show marked variations in redox status and dissolved As concentrations. Arsenic concentration in groundwater of the Ganges Flood Plain (GFP) is characteristically low, where high Mn concentrations indicate redox buffering by reduction of Mn(IV)-oxyhydroxides. Low DOC, HCO3-, NH4+ and high NO3- and So(4)(2-) concentrations reflect an elevated redox status in GFP aquifers. In contrast, As concentration in the Ganges Delta Plain (GDP) is very high along with high Fe and low Mn. In the Meghna Flood Plain (MFP), moderate to high As and Fe concentrations and low Mn are detected. Degradation of organic matter probably drives redox reactions in the aquifers, particularly in MFP and GDP, thereby mobilising dissolved As. Speciation calculations indicate supersaturation with respect to siderite and vivianite in the groundwater samples at MFP and GDP, but groundwater in the GFP wells is generally supersaturated with respect to rhodochrosite. Values of log P-CO2 at MFP and GDP sites are generally higher than at the GFP site. This is consistent with Mn(IV)-redox buffering suggested at the GFP site compared to Fe(III)-redox buffering at MFP and GDP sites.