Storm Daniel Extreme Flood Event in Thessaly, Greece: Assessing the Pollution Status of the Impacted Coastal Marine Areas through Extended Screening of Emerging Contaminants Using LC-TIMS-HRMS

In this study, we investigate the pollution status in impacted seawaters and sediments of coastal areas in the region of Thessaly, central Greece, following the Storm Daniel extreme flood event in September 2023, a phenomenon classified as the deadliest Mediterranean tropical-like cyclone in recorded history and one of the costliest cyclones beyond the North Atlantic. For this, an ultra high-performance liquid-chromatography-based wide-scope target screening of more than 2300 LC-amenable emerging contaminants (ECs) was carried out utilizing the technique of TIMS-QTOF-MS. Our results highlight the fact that the extreme floodwater runoff resulted in an extensive transportation of terrestrial derived material from the impacted areas and a major transport of plant protection products, pharmaceuticals, including even illicit drugs, surfactants, industrial chemicals, and per- and polyfluorinated alkyl compounds (PFAS) at sea, as a result of the overflowing of local wastewater treatment plants and the destruction of agricultural, industrial, and port facilities. Overall, the phenomenon resulted in a major alteration of the classification of the determined ECs in seawaters and most importantly in sediments of the study area, with potential implications for their environmental quality status.