Department of Environmental Science, School of Earth, Environment & Space Studies, Central University of Haryana, Jant Pali, Mahendergarh 123029, India.
School of Environmental Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
Int J Environ Res Public Health. 2018 Jan 23;15(2):183. doi: 10.3390/ijerph15020183.
A geochemical and speciation study of As, Fe, Mn, Zn, and Cu was performed using sequential extraction and statistical approaches in the core sediments taken at two locations-Rigni Chhapra and Chaube Chhapra-of the central Gangetic basin (India). A gradual increase in the grain size (varying from clay to coarse sands) was observed in both the core profiles up to 30.5 m depth. The concentrations of analyzed elements ranged as follows: 6.9-14.2 mg/kg for As, 13,849-31,088 mg/kg for Fe, 267-711 mg/kg for Mn, 45-164 mg/kg for Cu for Rigni Chhapra while for Chaube Chhapra the range was 7.5-13.2 mg/kg for As, 10,936-37,052 mg/kg for Fe, 267-1052 mg/kg for Mn, 60-198 mg/kg for Zn and 60-108 mg/kg for Cu. Significant amounts (53-95%) of all the fractionated elemental concentrations were bound within the crystal structure of the minerals as a residual fraction. The reducible fraction was the second most dominant fraction for As (7% and 8%), Fe (3%), Mn (20% and 26%), and Cu (7% and 6%) respectively for both the cores. It may be released when aquifers subjected to changing redox conditions. The acid soluble fraction was of most interest because it could quickly mobilize into the water system which formed the third most dominating among all three fractions. Four color code of sediments showed an association with total As concentration and did not show a relation with any fraction of all elements analyzed. The core sediment was observed enriched with As and other elements (Cu, Fe, Mn, and Zn). However, it fell under uncontaminated to moderately contaminate which might exhibit a low risk in prevailing natural conditions. X-ray diffraction analyses indicated the availability of siderite and magnetite minerals in the core sediments in a section of dark grey with micaceous medium sand with organic matter (black).
采用连续提取和统计方法，对印度恒河盆地中部的两个地点（Rigni Chhapra 和 Chaube Chhapra）采集的岩芯沉积物中的 As、Fe、Mn、Zn 和 Cu 进行了地球化学和形态研究。在两个岩芯剖面中，粒度逐渐增加（从粘土到粗砂），深度达到 30.5 米。分析元素的浓度范围如下：Rigni Chhapra 的 As 为 6.9-14.2mg/kg，Fe 为 13849-31088mg/kg，Mn 为 267-711mg/kg，Cu 为 45-164mg/kg；而 Chaube Chhapra 的 As 为 7.5-13.2mg/kg，Fe 为 10936-37052mg/kg，Mn 为 267-1052mg/kg，Zn 为 60-198mg/kg，Cu 为 60-108mg/kg。所有分馏元素浓度的大部分（53-95%）都结合在矿物的晶体结构中作为残余物。可还原部分是第二大主导部分，对于 As（7%和 8%）、Fe（3%）、Mn（20%和 26%）和 Cu（7%和 6%）分别为两个核心。当含水层处于不断变化的氧化还原条件下时，它可能会被释放出来。酸可溶部分最受关注，因为它可以迅速进入水系中，在所有三个部分中形成第三大主导部分。沉积物的四个颜色代码与总 As 浓度有关，与分析的所有元素的任何部分都没有关系。岩芯沉积物富含 As 和其他元素（Cu、Fe、Mn 和 Zn）。然而，它属于无污染到中度污染，在目前的自然条件下可能表现出低风险。X 射线衍射分析表明，在一段深灰色带有云母状中砂和有机质（黑色）的岩芯沉积物中存在菱铁矿和磁铁矿矿物。
