伊索斯卡普作为一个区域规模的工具,用于追踪北方平原的地下水循环,美国
Arijeet Mitra1, Randall Hughes2, Tracy Zacher2
1Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, New York 10032, United States.
Environmental science & technology
|December 9, 2025
概括
南达科他州部落井中的地下水污染对健康构成风险. 同位素分析揭示了独特的氧化还原区控制释放和去除,指导有针对性的监测和干预策略.
科学领域:
- 环境科学 环境科学
- 地质化学 地质化学
- 水文地质学 水文地质学
背景情况:
- 地下水的 (U) 污染是一个重大的健康问题,特别是对于使用私人井的美洲原住民社区.
- 了解地下水中的循环对于评估和减轻暴露风险至关重要.
研究的目的:
- 在南达科他州的一个部落地区调查地下水度,同位素特征 (δ238U和234U/238U) 以及相关的氧化还原敏感元素.
- 划定地质化学环境和控制在砂岩含水层中的行为的氧化还原机制.
- 为这个含水层系统开发了第一个 δ238U 和 234U/238U 的同位体.
主要方法:
- 来自140个私人井的地下水样本分析了的度, δ238U,234U/238U,以及对氧化还原敏感的元素 (Fe,Mn,NO3-,Se,V).
- 集群分析和统一多重近似和投影 (UMAP) 的应用用于地球化学环境的识别.
- 对同位素数据进行空间映射,以创建δ238U和234U/238U同位素.
主要成果:
- 的度在0.4至48.2μg/L之间,其中5%超过了EPA的30μg/L的MCL.
- 确定了不同的氧化还原区域:东北地区的氧化区域显示出较高的U和正的δ238U,而西南地区的减少区域显示出较低的U和负的δ238U.
- 234U/238U值表示不同U源的近距离和沿流路的输送距离.
结论:
- 氧化溶解在东北释放,而在西南减少条件促进其去除.
- 地质化学和同位素数据成功地在砂岩水层中划出了三个不同的氧化还原环境.
- 东北地区需要持续监测和潜在干预,以减少暴露风险.
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