School of Earth, Environment and Society, McMaster University, Canada.
Water Science and Technology Directorate, Environment and Climate Change Canada, Canada.
Environ Pollut. 2021 May 1;276:116474. doi: 10.1016/j.envpol.2021.116474. Epub 2021 Jan 11.
Many types of contaminants of emerging concern (CECs), including per- and poly-fluoroalkyl substances (PFAS), have been found in leachate of operating municipal landfills. However, there is only limited information on CECs presence in leachate of historic landfills (≥3 decades since closure, often lacking engineered liners or leachate collection systems) at concentrations that may pose a risk to nearby wells and surface water ecosystems. In this study, 48 samples of leachate-impacted groundwater were collected from 20 historic landfills in Ontario, Canada. The CECs measured included artificial sweeteners (ASs), PFAS, organophosphate esters (OPE), pharmaceuticals, bisphenols, sulfamic acid, perchlorate, and substituted phenols. The common presence of the AS saccharin, a known indicator of old landfill leachate, combined with mostly negligible levels of the AS acesulfame, an indicator of modern wastewater, revealed that most samples were strongly influenced by leachate and not cross-contaminated by wastewater (which can contain these same CECs). Several landfills, including ones closed in the 1960s, had total PFAS concentrations similar to those previously measured at modern landfills, with a maximum observed here of 12.7 μg/L. Notably elevated concentrations of several OPE, sulfamic acid, cotinine, and bisphenols A and S were found at many 30-60 year-old landfills. There was little indication of declining concentrations with landfill age, suggesting historic landfills can be long-term sources of CECs to groundwater and that certain CECs may be useful tracers for historic landfill leachate. These findings provide guidance on which CECs may require monitoring at historic landfill sites and wastewater treatment plants receiving their effluent.
许多新兴关注污染物（CECs）类型，包括全氟和多氟烷基物质（PFAS），已在运行中的城市垃圾填埋场的渗滤液中被发现。然而，有关历史垃圾填埋场（关闭时间超过 30 年，通常缺乏工程衬垫或渗滤液收集系统）渗滤液中 CECs 存在情况的信息有限，这些污染物的浓度可能对附近的水井和地表水生态系统构成风险。在这项研究中，从加拿大安大略省的 20 个历史垃圾填埋场采集了 48 份受渗滤液影响的地下水样本。测量的 CECs 包括人工甜味剂（ASs）、PFAS、磷酸酯（OPE）、药品、双酚、氨基磺酸、高氯酸盐和取代酚。甜味剂糖精的普遍存在，这是旧垃圾渗滤液的已知指标，再加上含量可忽略不计的乙酰磺胺酸钾，这是现代废水的指标，表明大多数样本受到渗滤液的强烈影响，而不是受到废水的交叉污染（废水中可能含有这些相同的 CECs）。包括那些在 20 世纪 60 年代关闭的垃圾填埋场在内的几个垃圾填埋场，其总 PFAS 浓度与之前在现代垃圾填埋场测量的浓度相似，这里观察到的最高浓度为 12.7μg/L。在许多 30 至 60 年的旧垃圾填埋场中，发现了几种 OPE、氨基磺酸、可替宁、双酚 A 和 S 的浓度显著升高。随着垃圾填埋场年龄的增长，浓度下降的迹象很少，这表明历史垃圾填埋场可能是地下水 CECs 的长期来源，某些 CECs 可能是历史垃圾渗滤液的有用示踪剂。这些发现为哪些 CECs 可能需要在历史垃圾填埋场和接收其废水的污水处理厂进行监测提供了指导。
