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Mutual Relationship of Arsenic Release Mechanism and salinity of Groundwater in Bangladesh

孟加拉国砷释放机制与地下水盐度的相互关系

基本信息

批准号：
15404005
负责人：
ISHIBASHI Yoshinobu
金额：
$ 5.95万
依托单位：
Tohoku Gakuin University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-15404005/
关键词：
Bangladesh Arsenic Contamination Release of Arsenic Fluidization Model of Groundwater Cell Surface Engineering Adverse effect of salination 地下水物資流動モデルヒ素溶出機構表面表層工学

项目摘要

Factors analysis of arsenic release, arsenic removal by cell surface engineering and Arsenic Transport analysis for pumping from deep aquifer in South Bangladesh were performed, mainly.A marked increase in arsenic release was recognized With sewage sludge content as organic matter from laboratory experiments. Maximum arsenic release was reconfirmed when the value of oxidation-reduction potential was around -80 mV. However, the relationship between divalent iron or hydrogen carbonate ion and arsenic release did not find out.On the other hand, distribution coefficient (k) in equilibrium between arsenic adsorption from water to solids and arsenic release from solids to water was 0.69×10^<-7> m^3/mg. The value was similar to the distribution coefficient of shallow aquifer in Bangladesh.lamB and arsR genes were combined with plasmid pTV118N for cell surface engineering, and more than 70 percent of arsenic was removed. But a problem, which lamB and arsR were inserted suitably or not, was still remained.At present, Bangladeshi people are using arsenic contaminated shallow groundwater. In the years ahead, deep aquifer which arsenic concentration is low would be the water sources. Therefore, model analyses of arsenic transport were performed in each depth of wells using field data in Bangladesh. As a result, arsenic concentration in shallow aquifer would be low, gradually, with the passage of time. On the contrary, arsenic concentration in deep aquifer would be increased little by little. If a time until reaction of adsorption and desorption becomes equilibrium condition assumed five years, arsenic contamination would progress to deep aquifer where the depth is -70 m in one hundred years later as one calculation.

通过对孟加拉国南部深层地下水中砷释放的影响因素分析、细胞表面工程除砷研究和砷迁移分析，发现以污泥为有机质时，砷释放量明显增加。当氧化还原电位为-80 mV左右时，砷的释放量最大。另一方面，砷从水到固体的吸附和砷从固体到水的释放之间的平衡分配系数（k）为0.69×10^<-7>m^3/mg。将lamB和arsR基因与质粒pTV 118 N结合进行细胞表面工程，去除砷70%以上。但是，目前孟加拉国人民使用的是砷污染的浅层地下水，这就存在着lamB和arsR是否合适的问题。未来几年，砷含量较低的深层含水层将成为水源。因此，在孟加拉国使用现场数据，在每个深度的威尔斯进行砷迁移的模型分析。结果表明，随着时间的推移，浅层含水层中砷的浓度会逐渐降低。相反，深层含水层中的砷浓度会逐渐增加。如果假设吸附和解吸反应达到平衡状态的时间为5年，则砷污染将在100年后向深度为-70 m的深层含水层发展。