Efficient workflow for suspect screening analysis to characterize novel and legacy per- and polyfluoroalkyl substances (PFAS) in biosolids

Abstract

Land application of treated sewage sludge (also known as biosolids) is considered a sustainable route of disposal because it reduces waste loading into landfills while improving soil health. However, this waste management practice can introduce contaminants from biosolids, such as per- and polyfluoroalkyl substances (PFAS), into the environment. PFAS have been observed to be taken up by plants, accumulate in humans and animals, and have been linked to various negative health effects. There is limited information on the nature and amounts of PFAS introduced from biosolids that have undergone different treatment processes. Therefore, this study developed analytical techniques to improve the characterization of PFAS in complex biosolid samples. Different clean-up techniques were evaluated and applied to waste-activated sludge (WAS) and lime-stabilized primary solids (PS) prior to targeted analysis and suspect screening of biosolid samples. Using liquid chromatography with high-resolution mass spectrometry, a workflow was developed to achieve parallel quantitative targeted analysis and qualitative suspect screening. This study found that concentrations of individual PFAS (27 targeted analytes) can range from 0.6 to 84.6 ng/g in WAS (average total PFAS = 241.4 ng/g) and from 1.6 to 33.8 ng/g in PS (average total PFAS = 72.1 ng/g). The suspect screening workflow identified seven additional PFAS in the biosolid samples, five of which have not been previously reported in environmental samples. Some of the newly identified compounds are a short-chain polyfluorinated carboxylate (a PFOS replacement), a diphosphate ester (a PFOA precursor), a possible transformation product of carboxylate PFAS, and an imidohydrazide which contains a sulfonate and benzene ring.

Levels of per- and polyfluoroalkyl substances (PFAS) in various wastewater-derived fertilizers – analytical investigations from different perspectives

“…Moreover, fluorinated pesticides (flufenacet and fludioxonil), pharmaceutical (flufenamic acid and pitavastatin) as well as aromatic compounds (4,4′-difluorobenzophenone and 1-cyclopropyl-6,7-difluoro-1,4-dihydro-8-hydroxy-4-oxo-3-quinoline-3-carboxylic acid) were also identified, which are all included in the EOF parameter. Our findings agree well with previous work of others 18,41,42 who were able to detect a broad range of different PFAS and fluorinated compounds in SLs/biosolids from France, Sweden and the US by LC-HRMS suspect screening.…”

“…LTC = low-temperature conversion (pyrolysis). Our ndings agree well with previous work of others 18,41,42 who were able to detect a broad range of different PFAS and uorinated compounds in SLs/biosolids from France, Sweden and the US by LC-HRMS suspect screening.…”

Quantitation of Total PFAS Including Trifluoroacetic Acid with Fluorine Nuclear Magnetic Resonance Spectroscopy

“…All chemicals, reagents, and sample preparation methods for wastewater samples are outlined in the Supporting Information and Table S1. Workflows for the complementary TOP assay and LC-HRMS analysis, including instrument parameters, were optimized and detailed in previous publications. The LC-HRMS analysis included a targeted quantitation (27 PFAS) as well as a suspect screening for PFAS from the U.S. EPA Masterlist (>12000 PFAS) using Fluoromatch Flow 2.2 .…”

“…Workflows for the complementary TOP assay and LC-HRMS analysis, including instrument parameters, were optimized and detailed in previous publications. The LC-HRMS analysis included a targeted quantitation (27 PFAS) as well as a suspect screening for PFAS from the U.S. EPA Masterlist (>12000 PFAS) using Fluoromatch Flow 2.2 . Wastewater samples were designated WWa for treatment via TOP assay and WWb for analysis via LC-HRMS.…”

“…The LC-HRMS analysis included a targeted quantitation (27 PFAS) as well as a suspect screening for PFAS from the U.S. EPA Masterlist (>12000 PFAS) using Fluoromatch Flow 2.2. 34 Wastewater samples were designated WWa for treatment via TOP assay and WWb for analysis via LC-HRMS. The terminal −CF 3 group used for PFAS quantification was observed in a standard containing 31 PFAS from a variety of subclasses to establish the signal of −CF 3 at −82.4 ppm, which was consistent with previous 19 F-NMR PFAS analyses.…”