State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 10069, China.
State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; CAS Center for Excellence in Deep Earth Science, Guangzhou 510640, China; University of Chinese Academy of Sciences, Beijing 10069, China.
Sci Total Environ. 2023 Feb 1;858(Pt 2):159821. doi: 10.1016/j.scitotenv.2022.159821. Epub 2022 Nov 2.
Shale gas exploitation is a water-intensive process, generating flowback and produced water (FPW) with complex chemical compositions. Reuse, disposal and treatment of FPW are of increasing concern, because of the potential risk of FPW contamination to the surrounding aquatic environment and drinking water sources when emitted. Among numerous organic substances present in FPW, of particular concern are those that are persistent, mobile and toxic (PMT) and very persistent and very mobile (vPvM). PMT and vPvM substances have the greatest potential to spread in groundwater and are the hardest to remediate. This study presents the outcome of a literature review to identify organic compounds that were previously detected in FPW. The 162 target compounds identified from this review were assessed to see if they can be considered PMT/vPvM substances based on their substance properties. Our results indicated that most FPW substances are "not PMT", accounting for 108 (66.7 %) compouds. In total 22 FPW substances can be considered PMT/vPvM or very likely to meet this criteria if more data were available. Examples of PMT substances in FPW include anthracene, 1,4-dioxane and 1,4-dichlorobenzene. PMT/vPvM compounds identified in FPW should be prioritized for risk management measures and monitoring in order to protect regional water resources.
页岩气开采是一个耗水的过程，会产生具有复杂化学成分的返排液和采出水（FPW）。由于 FPW 排放可能对周围水环境污染和饮用水源造成潜在风险，因此 FPW 的再利用、处置和处理越来越受到关注。在 FPW 中存在的众多有机物质中，特别令人关注的是那些持久性、迁移性和毒性（PMT）以及非常持久性和非常迁移性（vPvM）的物质。PMT 和 vPvM 物质具有在地下水中扩散的最大潜力，也是最难修复的。本研究通过文献回顾，确定了先前在 FPW 中检测到的有机化合物。从本次综述中确定的 162 种目标化合物，根据其物质特性，评估它们是否可以被视为 PMT/vPvM 物质。我们的结果表明，大多数 FPW 物质“不是 PMT”，占 108 种（66.7%）化合物。如果有更多的数据可用，总共 22 种 FPW 物质可以被认为是 PMT/vPvM 物质或很可能符合这一标准。FPW 中 PMT 物质的例子包括蒽、1,4-二恶烷和 1,4-二氯苯。应优先考虑 FPW 中识别出的 PMT/vPvM 化合物，以采取风险管理措施和监测，从而保护区域水资源。
