Source-related smart suspect screening in the aqueous environment: search for tire-derived persistent and mobile trace organic contaminants in surface waters

Abstract

A variant of suspect screening by liquid chromatography-high-resolution mass spectrometry (LC-HRMS) is proposed in this study: Samples of a potential source of contamination and of an environmental sample close to this source are first analyzed in a non-targeted manner to select source-related suspects and to identify them. The suspect list compiled from such an exercise is then applied to LC-HRMS data of environmental samples to ascribe and to identify persistent and mobile contaminants in the water cycle that may originate from the source under study. This approach was applied to tire crumb rubber (source) and road dust (close to source); by comparison of the two data sets, 88% of the features detected in tire leachate could be excluded. Of the 48 suspects remaining, a total of 41 could be tentatively identified as either related to hexamethoxymethyl melamine or cyclic amines, benzothiazoles, or glycols. Subsequently, environmental samples were searched for these suspects: 85% were determined in an urban creek after a combined sewer overflow and 67% in the influent of a municipal wastewater treatment plant (WWTP). These exceptionally high rates of positive findings prove that this source-related smart suspect screening effectively directs the effort of selecting and identifying unknown contaminants to those related to the source of interest. The WWTP effluent and the urban creek during dry weather also showed the presence of numerous contaminants that may stem from tire and road wear particles (TRWP) in road runoff. Contribution from other sources, however, cannot be ruled out.

The Tire Wear Compounds 6PPD-Quinone and 1,3-Diphenylguanidine in an Urban Watershed

“…Several chemicals that are used in the manufacturing of tires and/or the transformation products of these compounds are transported in road runoff into surface waters (Unice et al 2015 ; Seiwert et al 2020 ). Untreated road runoff is a significant source of these contaminants in the aquatic environment (Hou et al 2019 ).…”

“…Another tire wear compound, the aryl-amine compound, 1,3-diphenylguanidine (DPG) has been detected in urban surface waters (Peter et al 2018 ; Wagner et al 2018 ; Zahn et al 2019 ; Seiwert et al 2020 ). DPG is used as a catalyst in tire production to accelerate the cross-linking of rubber material with sulfur (Fishbein 1991 ).…”

Road Runoff Characterization: Ecotoxicological Assessment Combined with (Non-)Target Screenings of Micropollutants for the Identification of Relevant Toxicants in the Dissolved Phase

“…This original topdown approach (from complex samples to single molecules) represents an effective way of characterizing complex environmental contaminants mixtures. Establishing specific environmental HRMS signatures is still an emerging, promising but challenging strategy to classify urban chemical sources and poorly documented to date [14,15]. Even fewer studies coupled HRMS and toxicological analysis, for example, applied to the detection of contaminants in RR-exposed fish tissues [16], or ecotoxicological assessment, leading for instance to the identification of a highly toxic quinone transformation product of 6PPD for coho salmon [72].…”

“…Thus, non-target screening (NTS) is increasingly used to complete the characterization of micropollutant contamination of samples without focusing on one or more families of molecules, but by examining the sample content as a whole, unraveling several hundreds to thousands of unknown molecules [13]. Few studies of this type have been carried out so far on RR samples [14,15] and even less coupling HRMS and toxicological analysis [16].…”

A Deep Dive into the Complex Chemical Mixture and Toxicity of Tire Wear Particle Leachate in Fathead Minnow

“…2009), was also abundant in tire crumb rubber, road dust and road run-off (Peter et al 2018;Seiwert et al 2020). DPG and DHU have been reported at concentrations of 100±16 µg/g and 18±2 µg/g in tire wear (Peter et al 2020), and together with CPU have been associated with the coho mortality signature in North America (Peter et al 2018).…”