Energy & Geoscience Institute, The University of Utah, Salt Lake City, UT, 84108, USA; Department of Civil & Environmental Engineering, The University of Utah, Salt Lake City, UT, 84112, USA.
Petroleum Recovery Research Center, New Mexico Institute of Mining and Technology, Socorro, NM, 87801, USA.
Chemosphere. 2023 Apr;321:138048. doi: 10.1016/j.chemosphere.2023.138048. Epub 2023 Feb 3.
Leakage from geologic CO sequestration (GCS) sites to overlying shallow drinking water aquifers is a tangible risk. A primary purpose of this study is to assess the potential impacts of CO leakage into a fresh-water aquifer with associated CO-water-sediment interactions. The study site is the Ogallala aquifer overlying an active demonstration-scale GCS site in north Texas, USA. Using the results of combined batch experiments and reactive transport simulations, we discuss the effects of salinity on potential trace metal release and the potential for groundwater quality recovery after leakage ceases. RESULTS: suggest that trace metals are released from sediment due to impure carbonate mineral dissolution and cation exchange with exposure to aqueous CO. Concentrations of Mn, Zn and Sr might exceed the U.S. Environmental Protection Agency's (EPA) limits. After CO leakage stops, most cation concentrations decrease to levels observed before leakage quickly, suggesting that water quality may not be a long-term concern. However, saline water that co-leaks with CO may increase salinity of a shallow aquifer and induce more trace metals release from the sediment. In most cases, pH is sensitive to even small increases of CO, suggesting that pH may be a sufficiently sensitive parameter for detecting CO leakage.
地质封存（GCS）场地的 CO 泄漏到上覆浅层饮用水含水层是一个切实存在的风险。本研究的主要目的是评估 CO 泄漏到与 CO-水-沉积物相互作用相关的淡水含水层中的潜在影响。研究地点是美国德克萨斯州北部一个活跃的示范规模 GCS 场地上方的奥加拉拉含水层。利用批处理实验和反应传输模拟的综合结果，我们讨论了盐度对潜在痕量金属释放的影响，以及泄漏停止后地下水质量恢复的可能性。结果表明，痕量金属是由于不纯碳酸盐矿物溶解和与暴露于水溶液中的 CO 进行阳离子交换而从沉积物中释放出来的。Mn、Zn 和 Sr 的浓度可能超过美国环境保护署（EPA）的限值。CO 泄漏停止后，大多数阳离子浓度迅速下降到泄漏前的水平，这表明水质可能不是一个长期问题。然而，与 CO 一起泄漏的盐水可能会增加浅层含水层的盐度，并从沉积物中释放更多的痕量金属。在大多数情况下，即使 CO 略有增加，pH 值也很敏感，这表明 pH 值可能是检测 CO 泄漏的一个足够敏感的参数。
