Menezes Osmar, Srivastava Kartika, Ferreira Bianca, Field Jim A, Root Robert A, Chorover Jon, Abrell Leif, Sierra-Alvarez Reyes
Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ, 85721, USA; Departamento de Engenharia Civil e Ambiental, Universidade Federal de Pernambuco, Recife, PE, 50740-600, Brazil.
Department of Chemical and Environmental Engineering, The University of Arizona, Tucson, AZ, 85721, USA.
Chemosphere. 2024 Dec;369:143887. doi: 10.1016/j.chemosphere.2024.143887. Epub 2024 Dec 6.
The widespread presence of per- and polyfluoroalkyl substances (PFAS) in the environment, driven by extensive industrial use, has raised global concerns due to their persistence and adverse health effects. Despite the increased regulatory focus on a sub-set of well-known PFAS, over 12,000 compounds exist, many poorly characterized. Our study assessed hidden PFAS concentrations, undetectable by standard LC-MS/MS analysis, in contaminated groundwater. We analyzed total oxidizable precursors (TOP) via TOP assay followed by LC-MS/MS, and total organic fluorine (TOF) via combustion ion chromatography (CIC). Results were compared with those from LC-MS/MS analysis of 25 individual PFAS (∑PFAS25), representing the non-hidden PFAS fraction. We also evaluated the removal of hidden PFAS employing conventional and novel adsorbents. Groundwater samples from drinking water sources and contaminated military sites in the USA showed varying PFAS contamination levels as indicated by TOF values ranging from non-detect (<0.7 μg L) to 40.2 μg L. ∑PFAS25 was a major fraction of the TOF (41.7 - 92.8%) in some samples, whereas in others it only accounted for 5.1 - 20.4% of the TOF. The remaining percentages consisted of hidden PFAS not detected by conventional LC-MS/MS, but detectable as TOF by CIC. Organic fluorine content of oxidizable precursors accounted for 0.0-39.0% of TOF content, depending on the sample. Selected samples underwent adsorption with activated carbon (AC), anion exchange resin (IX), polyaniline (PANI), and poly-o-toluidine (POT). All adsorbents removed the hidden PFAS less effectively than the PFAS quantified by direct LC-MS/MS techniques. This is likely because PFAS adsorbents investigated to date primarily target anionic per- and polyfluoroalkyl acids, not effectively removing cationic, neutral, or zwitterionic hidden PFAS. AC exhibited the best overall performance among the investigated adsorbents. The results demonstrate that measuring TOP and TOF concentrations is effective for evaluating the removal of hidden PFAS in groundwater remediation.
由于广泛的工业用途，全氟和多氟烷基物质（PFAS）在环境中广泛存在，因其持久性和对健康的不利影响而引起全球关注。尽管监管机构对一部分知名的PFAS的关注度有所提高，但仍存在超过12,000种化合物，其中许多特性尚不明确。我们的研究评估了受污染地下水中标准液相色谱 - 串联质谱（LC-MS/MS）分析无法检测到的隐藏PFAS浓度。我们通过TOP分析然后进行LC-MS/MS分析总可氧化前体（TOP），并通过燃烧离子色谱法（CIC）分析总有机氟（TOF）。将结果与25种单独PFAS（∑PFAS25）的LC-MS/MS分析结果进行比较，∑PFAS25代表非隐藏PFAS部分。我们还评估了使用传统和新型吸附剂去除隐藏PFAS的情况。美国饮用水源和受污染军事基地的地下水样本显示出不同的PFAS污染水平，TOF值范围从未检测到（<0.7 μg/L）到40.2 μg/L不等。在一些样本中，∑PFAS25是TOF的主要部分（41.7 - 92.8%），而在其他样本中，它仅占TOF的5.1 - 20.4%。其余百分比由传统LC-MS/MS未检测到但CIC可检测为TOF的隐藏PFAS组成。可氧化前体的有机氟含量占TOF含量的0.0 - 39.0%，具体取决于样本。选定的样本用活性炭（AC）、阴离子交换树脂（IX）、聚苯胺（PANI）和聚邻甲苯胺（POT）进行吸附。所有吸附剂去除隐藏PFAS的效果都不如直接LC-MS/MS技术定量的PFAS。这可能是因为迄今为止研究的PFAS吸附剂主要针对阴离子全氟和多氟烷基酸，不能有效去除阳离子、中性或两性离子隐藏PFAS。在研究的吸附剂中，AC表现出最佳的整体性能。结果表明，测量TOP和TOF浓度对于评估地下水修复中隐藏PFAS的去除效果是有效的。
