• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Arsenic mobility and attenuation in a natural wetland at Terra Mine, Northwest Territories, Canada.
【24h】

Arsenic mobility and attenuation in a natural wetland at Terra Mine, Northwest Territories, Canada.

机译：加拿大西北地区Terra Mine天然湿地中的砷迁移率和衰减。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Elevated arsenic (As) concentrations in surface water from storing mine tailings in lakes can have a negative impact on local and downstream vegetation and aquatic life. At Terra Mine, an abandoned silver and copper mine in the Northwest Territories, tailings storage in Ho-Hum Lake has resulted in dissolved As concentrations of 50-80 mug/L, exceeding the 5 mug/L maximum guideline for aquatic life. A natural wetland located downstream appears to be attenuating As from surface water. The objectives of this study was to understand the sources of As to the wetland, the effectiveness of the wetland to sequester As, the form and stability of As in the sediments, the processes controlling As mobility, and the effect of seasonal changes in the wetland in the dissolved phase. Arsenic bound to the sediments was determined by analyzing for bulk composition, and As speciation and element association were identified using synchrotron-based bulk XANES and ESEM analysis.;While As was accumulating in the sediments at most sites in the wetland over the summer, these results suggest that the wetland was not effectively sequestering dissolved As from the surface water, and that sediment-water cycling of As in the wetland as a result of seasonal redox variations were contributing As in the surface water.;Arsenic enters the wetland by surface flow from Ho-Hum Lake, subsurface flow through the waste rock airstrip, and by windblown dust. In spring, dissolved As concentrations in surface water increased downstream. In late summer, a decrease in concentration was observed in the upstream portion of the wetland, however As returned to lake concentrations further downstream. Sediment As concentrations increased over the summer. ESEM and bulk XANES indicate that As was associated with (oxy)hydroxides and secondary sulphides. In the spring, when water levels were high from snow melt, (oxy)hydroxides formed and captured As, while sulphide oxidation in the sediments lead to the release of As into surface water. Over the summer, the onset of reducing conditions from microbial activity drove the formation of As-bearing sulphides and dissolution of (oxy)hydroxides.
机译：在湖中储存矿山尾矿后，地表水中砷（As）浓度升高，可能会对当地和下游的植被以及水生生物产生负面影响。在西北地区一个废弃的银铜矿山Terra Terra矿中，Ho-Hum湖的尾矿储存导致溶解的As浓度为50-80马克杯/升，超过了5马克/升的水生生物最高标准。位于下游的天然湿地似乎正在从地表水中衰减As。这项研究的目的是了解湿地砷的来源，湿地螯合砷的有效性，沉积物中砷的形式和稳定性，控制砷迁移率的过程以及湿地季节性变化的影响。在溶解阶段。通过分析堆积成分确定砷与沉积物的结合，并使用基于同步加速器的大量XANES和ESEM分析确定砷的形态和元素缔合;尽管夏季大部分时间湿地中沉积物中的砷积累，但这些结果表明，湿地不能有效地从地表水中分离出溶解态的As，并且由于季节性氧化还原变化，湿地中As的沉积物-水循环是地表水中As的贡献因素;砷通过地表水进入湿地来自Ho-Hum湖的地下流经废石跑道，并被风吹起。在春季，地表水中的溶解砷浓度向下游增加。在夏末，在湿地的上游部分观察到浓度降低，但是在更下游的地方又返回到湖泊中。夏季随着沉积物浓度增加。 ESEM和大量XANES表明，As与（羟基）氢氧化物和仲硫化物有关。在春季，当融雪中的水位高时，（氧）氢氧化物形成并捕获了As，而沉积物中的硫化物氧化导致As释放到地表水中。在整个夏天，由于微生物活动而导致的还原条件的开始，导致了含砷硫化物的形成和（氧）氢氧化物的溶解。

著录项

  • 作者

    Sealey, Heather Nicole.;

  • 作者单位

    Queen's University (Canada).;

  • 授予单位 Queen's University (Canada).;
  • 学科 Biogeochemistry.;Geochemistry.
  • 学位 M.Sc.
  • 年度 2011
  • 页码 223 p.
  • 总页数 223
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号