Currell Matthew, Northby Nathan, Netherway Pacian
School of Engineering and Built Environment, Griffith University, Nathan 4111, QLD, Australia; Australian Rivers Institute, Griffith University, Nathan 4111, QLD, Australia; School of Engineering, RMIT University, Melbourne 3000, VIC, Australia.
School of Engineering, RMIT University, Melbourne 3000, VIC, Australia; Geosyntec Consultants, Australia.
Chemosphere. 2024 Mar;352:141345. doi: 10.1016/j.chemosphere.2024.141345. Epub 2024 Jan 31.
Understanding groundwater contamination from legacy landfills, including fate and transport of Per- and polyfluoroalkyl substances (PFAS), is a critical challenge for sustainable urban renewal. We analysed groundwater within and surrounding legacy landfills at Fishermans Bend for PFAS and complementary hydrochemical indicators. Sampling in 2017 revealed extensive PFAS contamination from the landfills. We re-examined concentrations after a 3-year period, to assess natural source attenuation and evolution of the contaminant plumes. Total PFAS (∑PFAS) ranged from 88 to 973 ng/L, with relatively high concentrations (mean = 500 ng/L, n = 4) in samples directly within the waste mass of a large legacy municipal and industrial landfill (Port Melbourne Tip). Two samples on the boundary of a former construction and demolition waste landfill also had elevated PFAS concentrations (∑PFAS = 232 and 761.5 ng/L). Down-gradient of the landfills, groundwater showed reductions in total PFAS, though still maintained considerable loads (∑PFAS = 107.5-207.5 ng/L). Long-chained PFAS showed greatest reductions relative to chloride concentrations down-gradient of the landfills, consistent with sorption as the predominant removal mechanism. The dominant mass fractions detected were similar in 2017 and 2020 (median: PFOS > PFHxS > PFHxA > PFOA); comprising the widely known, persistent 'legacy' PFAS. Re-sampled bores returned similar concentrations of these PFAS in 2017 and 2020 (median %RPDs of 0.0, 9.3 and 15.4, for PFOS, PFOA, and PFHxS, respectively). However, there were marked increases in concentrations of certain PFAS in three bores - including a previously un-impacted background site. The results show limited attenuation of legacy landfill PFAS contamination in groundwater over a 3-year period.
了解遗留垃圾填埋场造成的地下水污染，包括全氟和多氟烷基物质（PFAS）的归宿和迁移，是可持续城市更新面临的一项关键挑战。我们分析了渔人湾遗留垃圾填埋场及其周边地下水中的PFAS和补充性水化学指标。2017年的采样显示垃圾填埋场存在广泛的PFAS污染。我们在3年后重新检测了浓度，以评估自然源衰减和污染物羽流的演变。总PFAS（∑PFAS）范围为88至973纳克/升，在一个大型遗留市政和工业垃圾填埋场（墨尔本港垃圾场）的废物堆内的样品中浓度相对较高（平均值 = 500纳克/升，n = 4）。一个 former construction and demolition waste landfill 的边界上的两个样品的PFAS浓度也有所升高（∑PFAS = 232和761.5纳克/升）。在垃圾填埋场的下游，地下水中的总PFAS有所减少，不过仍保持相当高的含量（∑PFAS = 107.5 - 207.5纳克/升）。与垃圾填埋场下游的氯化物浓度相比，长链PFAS的减少最为显著，这与吸附作为主要去除机制相一致。2017年和2020年检测到的主要质量分数相似（中位数：全氟辛烷磺酸>全氟己烷磺酸>全氟己酸>全氟辛酸）；包括广为人知的持久性“遗留”PFAS。2017年和2020年重新采样的钻孔中这些PFAS的浓度相似（全氟辛烷磺酸、全氟辛酸和全氟己烷磺酸的中位数相对百分比差异分别为0.0、9.3和15.4）。然而，三个钻孔中某些PFAS的浓度有显著增加——包括一个之前未受影响的背景场地。结果表明，在3年时间里，遗留垃圾填埋场的PFAS对地下水的污染衰减有限。
