Department of Agronomy, Purdue University, West Lafayette, IN 47907, USA.
Department of Agronomy, Purdue University, West Lafayette, IN 47907, USA; Department of Environmental & Ecological Engineering, Purdue University, West Lafayette, IN 47907, USA; Ecological Sciences & Engineering Interdisciplinary Graduate Program, Purdue University, West Lafayette, IN 47907, USA.
Sci Total Environ. 2024 Dec 1;954:176540. doi: 10.1016/j.scitotenv.2024.176540. Epub 2024 Sep 25.
The fate of per- and polyfluoroalkyl substances (PFAS) was evaluated at a site where municipal biosolids have been applied annually for 38 years as a waste management strategy. Soil cores (1.8 m in 30-cm sections), groundwater from four wells, and biosolids applied in 2022 were analyzed for PFAS (54 targeted, 17 semi-quantified) using liquid chromatography high resolution mass spectrometry including suspect screening. Total PFAS concentrations decreased with soil depth from 1700 ng/g to 2.06 ng/g. PFAS distribution in 2022 biosolids were 60 mol% perfluoroalkyl acid (PFAA) precursors and intermediates. The surface soil was dominated by long-chain PFAAs (67-76 mol%) reflecting precursor degradation after biosolids application. Presence of semi-quantified intermediates further reflects precursor degradation in surface soil. Long-chain PFAAs diminished with depth while short-chain PFAAs increased with up to 98 and 96 mol% short-chain PFAAs in the bottom depth and groundwater, respectively. PFAS distribution with depth is consistent with chain-length dependent sorption-impacted transport and the high organic carbon content of the surface soil (15.2 % OC) which subsequently decreased with depth (~2-3 % OC at >60 cm). High organic carbon content in the upper horizon is likely from decades of high biosolids application rates, which contributed to minimizing leaching of long-chain PFAS. While the well within the dedicated land disposal is not drinking water, for comparison only, PFAS concentrations in this well only marginally exceeded the EU drinking water directive for total PFAS and a few individual short-chain PFAS, but did exceed tenfold, the USEPA drinking water standard for PFOA.
对一个连续 38 年将城市生物固体作为废物管理策略进行每年施用量的地点进行了全氟和多氟烷基物质 (PFAS) 的命运评估。使用液相色谱高分辨质谱法（包括嫌疑筛查）对 1.8 米长的 30 厘米土壤芯、四口井的地下水和 2022 年施用量的生物固体进行了 54 种目标物和 17 种半定量的 PFAS 分析。PFAS 浓度随土壤深度从 1700ng/g 降至 2.06ng/g。2022 年生物固体中 PFAS 的分布为 60mol%全氟烷基酸 (PFAA) 前体和中间体。表层土壤主要由长链 PFAAs（67-76mol%）组成，反映出生物固体施用量后前体的降解。半定量中间产物的存在进一步反映了表层土壤中前体的降解。长链 PFAAs 随深度减少，而短链 PFAAs 增加，底部深度和地下水中的短链 PFAAs 分别高达 98 和 96mol%。PFAS 随深度的分布与链长依赖性吸附影响的传输以及表层土壤（15.2%OC）的高有机碳含量一致，随后随深度降低（>60cm 处约 2-3%OC）。上层土壤中高的有机碳含量可能是几十年高生物固体施用量的结果，这有助于最大限度地减少长链 PFAS 的淋失。虽然专用土地处置井不是饮用水，但仅为比较起见，该井中的 PFAS 浓度仅略高于欧盟总 PFAS 和少数个别短链 PFAS 的饮用水指令，但超过 10 倍，超过了美国环保署饮用水标准的 PFOA。
