Characterization of scrubber water discharges from ships using comprehensive suspect screening strategies based on GC-APCI-HRMS

Abstract

An extended suspect screening approach for the comprehensive chemical characterization of scrubber discharge waters from exhaust gas cleaning systems (EGCSs), used to reduce atmospheric shipping emissions of sulphur oxides, was developed. The suspect screening was based on gas chromatography coupled with high-resolution mass spectrometry (GC-HRMS) and focused on the identification of polycyclic aromatic hydrocarbons (PAHs) and their alkylated derivatives (alkyl-PAHs), which are among the most frequent and potentially toxic organic contaminants detected in these matrices. Although alkyl-PAHs can be even more abundant than parent compounds, information regarding their occurrence in scrubber waters is scarce. For compound identification, an in-house compound database was built, with 26 suspect groups, including 25 parent PAHs and 23 alkyl-PAH homologues. With this approach, 7 PAHs and 12 clusters of alkyl-PAHs were tentatively identified, whose occurrence was finally confirmed by target analysis using GC coupled with tandem mass spectrometry (GC-MS/MS). Finally, a retrospective analysis was performed to identify other relevant (poly)cyclic aromatic compounds (PACs) of potential concern in scrubber waters. According to it, 18 suspect groups were tentatively identified, including biphenyls, dibenzofurans, dibenzothiophenes, and oxygenated PAHs derivatives. All these compounds could be used as relevant markers of scrubber water contamination in heavy traffic marine areas and could be considered as potential stressors when evaluating scrubber water toxicity

This study has been carried out under the support of the Horizon 2020 EMERGE project (Grant agreement ID: 874990). M. Gros acknowledges her Ramon y Cajal contract (RYC2020-030324-I) funded by the MCIN/AEI 10.13039/501100011033 and by “ESF Investing in your future”. Authors also acknowledge the European Regional Development Fund (FEDER), the Generalitat de Catalunya through the Consolidated Research Group (SGR ICRA-ENV 2021 01282) and the funding from CERCA program