Peter Lynda, Modiri-Gharehveran Mahsa, Alvarez-Campos Odiney, Evanylo Gregory K, Lee Linda S
Department of Agronomy, Ecological Sciences & Engineering Interdisciplinary Graduate Program, Purdue University, West Lafayette, Indiana, USA.
Environmental & Ecological Engineering, Purdue University, West Lafayette, Indiana, USA.
J Environ Qual. 2025 Jan-Feb;54(1):41-53. doi: 10.1002/jeq2.20576. Epub 2024 May 30.
Carbon- and nutrient-rich biosolids are used in agriculture and land reclamation. However, per- and polyfluoroalkyl substances (PFAS) typically present in biosolids raise concerns of PFAS leaching to groundwater and plant uptake. Here, we investigated PFAS persistence and leaching from biosolids applied to a site constructed artificially to mimic degraded soils. Treatments included biosolids and biosolids blended with mulch applied at different rates to attain either one and five times the agronomic N rate for vegetable crops and a control treatment with synthetic urea and triple superphosphate fertilizer. Leachates were collected for a 2-year period from 15-cm depth zero-tension drainage lysimeters. Soils were analyzed post biosolids application. PFAS were quantified using isotope-dilution, solid-phase extraction and liquid chromatography tandem mass spectrometry. Leachate profiles exemplified an initial high total PFAS concentration, followed by a sharp decline and subsequent small fluctuations attributed to pre-existing soil conditions and rainfall patterns. Quantifiable PFAS in leachate were proportional to biosolids application rates. Short-chain perfluoroalkyl acids (CF < 6) were dominant in leachate, while the percentage of longer chains homologues was higher in soils. A 43% biosolids blend with mulch resulted in 21% lower PFAS leachate concentrations even with the blend application rate being 1.5 times higher than biosolids due to the blend's lower N-content. The blending effect was more pronounced for long-chain perfluoroalkyl sulfonic acids that have a greater retention by soils and the air-water interface. Biosolids blending as a pragmatic strategy for reducing PFAS leachate concentrations may aid in the sustainable beneficial reuse of biosolids.
富含碳和养分的生物固体被用于农业和土地复垦。然而，生物固体中通常存在的全氟和多氟烷基物质（PFAS）引发了人们对PFAS渗入地下水和被植物吸收的担忧。在此，我们研究了PFAS在人工构建以模拟退化土壤的场地中施用生物固体后的持久性和淋溶情况。处理包括生物固体以及与覆盖物混合的生物固体，以不同速率施用，达到蔬菜作物农艺氮用量的1倍和5倍，还有一个使用合成尿素和重过磷酸钙肥料的对照处理。在两年时间里，从15厘米深度的零张力排水渗滤计收集渗滤液。在施用生物固体后对土壤进行分析。使用同位素稀释、固相萃取和液相色谱串联质谱法定量PFAS。渗滤液剖面显示，最初全氟烷基物质总浓度较高，随后急剧下降，随后因土壤原有条件和降雨模式出现小波动。渗滤液中可量化的PFAS与生物固体施用量成正比。短链全氟烷基酸（CF < 6）在渗滤液中占主导，而长链同系物在土壤中的百分比更高。与覆盖物混合43%的生物固体导致PFAS渗滤液浓度降低21%，即使混合施用率比生物固体高1.5倍，这是因为混合物料的氮含量较低。对于在土壤和空气 - 水界面具有更强保留能力的长链全氟烷基磺酸，混合效果更为明显。将生物固体混合作为降低PFAS渗滤液浓度的实用策略，可能有助于生物固体的可持续有益再利用。
