Novel Mass Spectrometry Approaches for the Identification of Pesticides and Per- and Polyfluoroalkyl Substances in North Carolina Drinking Water Sources

Abstract

Water quality can be adversely impacted by a wide range of organic contaminants, including pesticides and per- and polyfluoroalkyl substances (PFAS). To support the assessment of water quality by liquid chromatography, ion mobility spectrometry, and tandem mass spectrometry, a database of collision cross sections was developed for pesticides. The database can be used in both targeted and nontargeted analyses of aqueous samples. Within the database, a clear separation occurs between pesticides and highly halogenated exposomic compounds, such as per- and polyfluoroalkyl substances (PFAS), polybrominated diphenyl ethers (PBDEs), and polychlorinated biphenyls (PCBs), which will be useful in nontargeted workflows as unknown features can be tentatively assigned to specific exposomic classes without a true identification. The utility of these methods for the assessment of water quality and human exposure was explored. Using the database, atrazine was identified in 3 out of 13 surface water samples (11-40 ng/L). To assess the potential impact of land-applied biosolids on aqueous PFAS concentrations, 13 surface water sites and 9 private wells were sampled near fields that had received biosolids. Eight of the surface water sites contained detectable PFAS at concentrations up to 1,880 ng/L, and eight of the private wells contained detectable PFAS at concentrations up to 194 ng/L. The primary subclasses identified in the samples were perfluoroalkyl sulfonic acids and perfluoroalkyl carboxylic acids.