Biogeochemical properties and potential risk of shallow arsenic-rich sediment layers to groundwater quality in Western Bangladesh

Nguyen Van Thinh, Masaru Matsumoto, Myo Zaw, Yoshihiro Kuwahara, Yiping Xie, Akinori Ozaki, Kiyoshi Kurosawa

研究成果: Contribution to journalArticle査読

抄録

The arsenic-contaminated groundwater has attracted attention in much south and southeast Asian deltas, however, mainly on the deep aquifers. Here, arsenic (As) concentration and its fractionation of the sediment cores in a shallow aquifer in Bangladesh were investigated using ICP-MS, FE-EPMA, XRD and 14C-AMS chronology techniques. The results of the present study indicated that the peak concentrations of As (54.7–79.1 µg/g) were in peat layers (at a depth of 7.5–8.0 m). Several types of iron (oxyhidr)oxides and framboidal pyrite, which contain As also, were found in the peat samples. The high concentrations of As were in an exchangeable form, As-bearing iron crystalline and As-bearing organic materials. We revealed that the As-rich peat layers were formed from 3170 to 3901 cal yrs before, due to the sea level decrease in this area. The 16S rRNA gene-based phylogenetic analysis revealed that the bacterial strains in the As-rich peats were mainly affiliated with genera Acinetobacter, Enterobacter, Escherichia, Bacillus, Clostridiaceae and Acinetobacter. The geo-accumulation index (Igeo) and ecological risk index assessment were calculated for the sediments, which shows that As-rich sediment layers were in range of moderately to heavily contaminated and considerable classes, respectively. Under the permanent saturated condition, the As-rich peat layers should be considered as an important potential driver of the groundwater As in this area.

本文言語英語
ジャーナルEnvironmental Geochemistry and Health
DOI
出版ステータス受理済み/印刷中 - 2021

All Science Journal Classification (ASJC) codes

  • 環境工学
  • 環境化学
  • 水の科学と技術
  • 環境科学(全般)
  • 地球化学および岩石学

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