Extended suspect screening to identify organic micropollutants and their transformation products as potential markers of wastewater contamination in riverine and coastal ecosystems

In this study, a comprehensive suspect screening of organic micropollutants (MPs), and some of their transformation products (TPs) and metabolites, was performed in waste, river and coastal waters from the Ebro Delta region (Catalonia, Spain). For this purpose, an automated suspect screening workflow was developed using two analytical steps: (i) identification of suspected compounds using on-line databases; and (ii) semi-quantification of identified compounds by using isotopic labelled standards. Using this strategy, several pollutants were identified comprising pharmaceuticals, pesticides, abused substances, personal care products, industrial chemicals and surfactants of major relevance in Catalonia. Additionally, their occurrence was evaluated along the wastewater-recipient water chain until they reach estuaries and the Mediterranean Sea. The most ecologically relevant compounds detected, that could be considered as suitable markers of wastewater contamination in freshwater and coastal ecosystems, were highlighted. Results reveal that some suspected TPs and metabolites were more ubiquitous than their parent compound and found at similar concentration levels. These results evidence that suspect screening methodologies can be a useful tool for the identification of relevant markers of wastewater contamination.