Simultaneous targeted and non-targeted analysis of contaminants in fertilizers in Quebec, Canada

In this study, an LC-MS based analytical method was developed and validated for the simultaneous targeted analysis (14 bisphenols and 14 plasticizers) and suspect screening of other plastic-related contaminants in various types of fertilizers. The ultrasound-assisted extraction method showed overall satisfactory performances, achieving a median absolute recovery of 85 % for the target compounds in different types of fertilizers. The method was applied to sixteen different types of fertilizers, including fertilizing residual materials (n = 8 types), one cattle manure, and seven mineral fertilizers collected in Quebec, Canada in 2022 and 2023. Relatively higher levels of the targeted bisphenols and plasticizers were detected in some fertilizing residual materials, such as municipal biosolids and deinking residues. 4-Hydroxyphenyl 4-isoprooxyphenylsulfone (D-8) and bis(2-ethylhexyl) phthalate (DEHP) were dominant contaminants in these matrixes, with concentrations up to 35.6 and 64.7 μg g^-1 dw, respectively. A non-targeted workflow was successfully applied to municipal biosolids and deinking residues, and >30 contaminants were identified across multiple chemical families at level 1 identification confidence, with most of them previously unreported in various types of fertilizers. For example, new color developers, N-(2-((Phenylcarbamoyl)amino)phenyl)benzenesulfonamide (NKK-1304) and 2,4-bis(phenylsulfonyl)phenol (DBSP), were reported in deinking residues. This work illustrates the complexity of the contaminant mixtures in fertilizers such as municipal biosolids and deinking residues.