School of Engineering, RMIT University, Melbourne, Australia.
School of Engineering, RMIT University, Melbourne, Australia.
Environ Pollut. 2019 May;248:101-113. doi: 10.1016/j.envpol.2019.02.018. Epub 2019 Feb 8.
The extent of per- and polyfluoroalkyl substances (PFAS) in groundwater surrounding legacy landfills is currently poorly constrained. Seventeen PFAS were analysed in groundwater surrounding legacy landfills in a major Australian urban re-development precinct. Sampling locations (n = 13) included sites installed directly in waste material and down-gradient from landfills, some of which exhibited evidence of leachate contamination including elevated concentrations of ammonia-N (≤106 mg/L), bicarbonate (≤1,740 mg/L) and dissolved methane (≤10.4 mg/L). Between one and fourteen PFAS were detected at all sites and PFOS, PFHxS, PFOA and PFBS were detected in all samples. The sum of detected PFAS (∑PFAS) varied from 26 ng/L at an ambient background site to 5,200 ng/L near a potential industrial point-source. PFHxS had the highest median concentration (34 ng/L; range: 2.6-280 ng/L) followed by PFOS (26 ng/L; range: 1.3-4,800 ng/L), PFHxA (19 ng/L; range: <LOQ - 46 ng/L) and PFOA (12 ng/L; range: 1.7-74 ng/L). Positive correlations between ∑PFAS, PFOA and other perfluoroalkyl carboxylic acids (PFCAs) (e.g. PFHxA) with typical leachate indicators including ammonia-N and bicarbonate were observed. In contrast, no such correlations were found with perfluoroalkyl sulfonic acids (PFSAs) (e.g., PFOS and PFHxS). In addition, a strong positive linear correlation (R = 0.69) was found between the proportion of PFOA in the sum of detected perfluorinated alkylated acids (PFOA/∑PFAA) and ammonia-N concentrations in groundwater. This is consistent with previous research showing relatively high PFOA/∑PFAA in municipal landfill leachates, and more conservative behaviour (e.g. less sorption and reactivity) of PFCAs during subsurface transport compared to PFSAs. PFOA/∑PFAA in groundwater may therefore be a useful indicator of municipal landfill-derived PFAA. One site with significantly elevated PFOS and PFHxS concentrations (4,800 and 280 ng/L, respectively) appears to be affected by point-source industrial contamination, as landfill leachate indicators were absent.
地下水周围遗留垃圾填埋场中持久性和多氟烷基物质 (PFAS) 的范围目前还没有得到很好的限制。在澳大利亚一个主要的城市重建区，对遗留垃圾填埋场周围的地下水进行了 17 种 PFAS 的分析。采样地点（n=13）包括直接安装在废物中的地点和垃圾填埋场的下游地点，其中一些地点显示出沥滤液污染的证据，包括氨氮（≤106mg/L）、重碳酸盐（≤1740mg/L）和溶解甲烷（≤10.4mg/L）浓度升高。所有地点均检测到 1 至 14 种 PFAS，所有样品中均检测到全氟辛烷磺酸 (PFOS)、全氟己基磺酸 (PFHxS)、PFOA 和 PFBS。检测到的 PFAS 总和（∑PFAS）从环境背景点的 26ng/L 到潜在工业点源附近的 5200ng/L 不等。PFHxS 的浓度最高（34ng/L；范围：2.6-280ng/L），其次是 PFOS（26ng/L；范围：1.3-4800ng/L）、PFHxA（19ng/L；范围：<LOQ-46ng/L）和 PFOA（12ng/L；范围：1.7-74ng/L）。∑PFAS、PFOA 和其他全氟烷基羧酸（PFCAs）（例如，PFHxA）与典型沥滤液指标（如氨氮和重碳酸盐）之间存在正相关关系。相比之下，与全氟烷基磺酸（PFSAs）（例如，PFOS 和 PFHxS）之间则没有这种相关性。此外，在地下水的 PFOA 在检测到的全氟烷基化酸总和中的比例（PFOA/∑PFAA）与氨氮浓度之间发现了强烈的正线性相关（R=0.69）。这与之前的研究一致，该研究表明城市垃圾填埋场沥滤液中 PFOA/∑PFAA 的比例相对较高，并且与 PFSAs 相比，PFCAs 在地下水中的迁移过程中表现出更保守的行为（例如，吸附和反应性较低）。因此，地下水的 PFOA/∑PFAA 可能是城市垃圾填埋场衍生的 PFAA 的有用指标。一个地点的 PFOS 和 PFHxS 浓度显著升高（分别为 4800ng/L 和 280ng/L），似乎受到点源工业污染的影响，因为没有发现垃圾填埋场沥滤液指标。
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