Concentrations of inorganic arsenic in groundwater, agricultural soils and subsurface sediments from the middle Gangetic plain of Bihar, India
Concentrations of inorganic arsenic in groundwater, agricultural soils and subsurface sediments from the middle Gangetic plain of Bihar, India
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DOI：
10.1016/j.scitotenv.2016.08.109
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发表时间：
2016-12-15
影响因子：
9.8
通讯作者：
Naidu, Ravi
中科院分区：
文献类型：
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作者：
Kumar, Manoj;Ramanathan, A. L.;Naidu, Ravi
测定了印度比哈尔邦恒河平原中部地下水、农业土壤和地下沉积物中砷（As）的无机形态[亚砷酸盐，As（III）和砷酸盐，As（V）]的浓度。大约73%的地下水样品（n = 19）显示As（III）为优势种，而27%的显示As（V）为优势种。农业土壤样品中As（III）的浓度从检测不到到40 μ g/kg不等，As（V）是观察到的主要种类（从1050到6835 μ g/kg不等），而总As浓度从3528到14,690 μ g/kg不等。地下沉积物中As的总提取浓度高于农业土壤（Methrapur为9119- 20，056 μ g/kg，Harail Chapar为4788- 19，681 μ g/kg），表明地下沉积物是As的来源。X射线衍射（XRD）和环境扫描电子显微镜（ESEM）的结果显示，在整个垂直截面下方存在赤铁矿和针铁矿，而磁铁矿仅在Methrapur和Harail Chapar的上部氧化层中观察到。铁氧化物的蚀变和纤维状针铁矿的存在表明成岩沉积物的存在。菱铁矿作为地下沉积物中砷的汇起着至关重要的作用。该研究还得出结论认为，存在于黑暗和灰色部分的有机物的分解促进氧化还原条件和触发动员As进入地下水。(C)© 2016 Elsevier B. V.版权所有。
Concentrations of inorganic forms [arsenite, As(III) and arsenate, As(V) of arsenic (As) present in groundwater, agricultural soils and subsurface sediments located in the middle Gangetic plain of Bihar, India were determined. Approximately 73% of the groundwater samples (n = 19) show As(III) as the dominant species while 27% reveals As(V) was the dominant species. The concentration of As(III) in agricultural soil samples varies from not detectable to 40 mu g/kg and As(V) was observed as the major species (ranging from 1050 to 6835 mu g/kg) while the total As.concentration varied from 3528 to 14,690 mu g/kg. Total extracted concentration of As was higher in the subsurface sediments (range 9119-20,056 mu g/kg in Methrapur and 4788-19,681 mu g/kg in Harail Chapar) than the agricultural soil, indicating the subsurface sediment as a source of As. Results of X-ray diffraction (XRD) and environmental scanning electron microscope (ESEM) revealed the presence of hematite and goethite throughout the vertical section below while magnetite was observed only in the upper oxidized layer at Methrapur and Harail Chapar. Alteration of Fe-oxides and presence of fibrous goethite indicatingpresence of diagenetic sediment. Siderite plays a crucial role as sinks to the As in subsurface sediments. The study also concluded that decomposition of organic matter present in dark and grey sections promote the redox conditions and trigger mobilization of As into groundwater. (C) 2016 Elsevier B.V. All rights reserved.