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Radioiodine concentrated in a wetland

机译：放射性碘集中在湿地

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摘要

Most subsurface environmental radioactivity contamination is expected to eventually resurface in riparian zones, or wetlands. There are a number of extremely sharp biogeochemical interfaces in wetlands that could alter radionuclide speciation and promote accumulation. The objective of this study was to determine if a wetland concentrated ~(129)I emanating from a former waste disposal basin located on the Savannah River Site (SRS) in South Carolina, USA. Additionally, studies were conducted to evaluate the role of sediment organic matter in immobilizing the radioiodine. Groundwater samples were collected along a 0.7-km transect away from the seepage basin and in the downstream wetlands. The samples were analyzed for ~(129)I speciation (iodide (I~-), iodate (IO_3~-), and organo-I). Groundwater ~(129)I concentrations in many locations in the wetlands (as high as 59.9 Bq L~(-1) ~(129)I) were greatly elevated with respect to the source term (5.9 Bq L~(-1) ~(129)I). ~(129)I concentration profiles in sediment cores were closely correlated to organic matter concentrations (r~2 - 0.992; n - 5). While the sediment organic matter promoted the uptake of ~(129)I to the wetland sediment, it also promoted the formation of a soluble organic fraction: 74% of the wetland groundwater ~(129)I could pass through a 1 kDa (＜1 nm) membrane and only 26% of the ~(129)I was colloidal. Of that fraction that could pass through a 1 kDa membrane, 39% of the ~(129)I was organo-I. Therefore, while wetlands may be highly effective at immobilizing aqueous ~(129)I, they may also promote the formation of a low-molecular-weight organic species that does not partition to sediments. This study provides a rare example of radioactivity concentrations increasing rather than decreasing as it migrates from a point source and brings into question assumptions in risk models regarding continuous dilution of released contaminants.
机译：预期大多数地下环境放射性污染最终将在河岸带或湿地重新出现。湿地中有许多极其尖锐的生物地球化学界面，它们可能会改变放射性核素的形态并促进积累。这项研究的目的是确定湿地是否集中来自美国南卡罗来纳州萨凡纳河站点（SRS）上一个前废物处理盆地的〜（129）I。另外，进行了研究以评估沉积物有机物在固定放射性碘中的作用。沿着距渗漏盆地和下游湿地0.7公里的断面收集地下水样品。分析了样品的〜（129）I形态（碘化物（I〜-），碘酸盐（IO_3〜-）和有机物I）。相对于源项（5.9 Bq L〜（-1）〜），湿地许多地方的地下水〜（129）I浓度（高达59.9 Bq L〜（-1）〜（129）I）大大提高。 （129）I）。沉积物岩心中的〜（129）I浓度分布与有机质浓度密切相关（r〜2-0.992； n-5）。沉积物有机质促进〜（129）I进入湿地沉积物，但也促进了可溶性有机物的形成：74％的湿地地下水〜（129）I可以通过1 kDa（＜1纳米膜），只有约26％的〜（129）I是胶体。在可以通过1 kDa膜的那部分中，〜（129）I的39％是有机I。因此，尽管湿地在固定〜（129）I水溶液方面可能非常有效，但它们也可能促进不分配至沉积物的低分子量有机物的形成。这项研究提供了一个罕见的放射性浓度随着从点源迁移而增加而不是减少的例子，并在风险模型中对释放污染物的连续稀释提出了假设。

著录项

  • 来源
    《Journal of Environmental Radioactivity》 |2014年第5期|57-61|共5页
  • 作者

    Daniel I. Kaplan; Saijin Zhang; Kimberly A. Roberts; Kathy Schwehr; Chen Xu; Danielle Creeley; Yi-Fang Ho; Hsiu-Ping Li; Chris M. Yeager; Peter H. Santschi;

  • 作者单位

    Savannah River National Laboratory (SRNL), Aiken, SC, USA;

    Department of Marine Science, Texas A&M University at Galveston, TX 77554, USA;

    Savannah River National Laboratory (SRNL), Aiken, SC, USA;

    Department of Marine Science, Texas A&M University at Galveston, TX 77554, USA;

    Department of Marine Science, Texas A&M University at Galveston, TX 77554, USA;

    Department of Marine Science, Texas A&M University at Galveston, TX 77554, USA;

    Department of Marine Science, Texas A&M University at Galveston, TX 77554, USA;

    Department of Marine Science, Texas A&M University at Galveston, TX 77554, USA;

    Los Alamos National Laboratory (LANL), Los Alamos, NM, USA;

    Department of Marine Science, Texas A&M University at Galveston, TX 77554, USA;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Radioiodine; Wetlands; Speciation; Iodide; Iodate; Natural organic matter;

    机译：放射性碘湿地;物种碘化物碘酸盐天然有机物;

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