Comprehensive monitoring of priority pollutants and emerging contaminants is considered necessary to provide insights concerning the quality of ecosystems. Chemicals such as plant protection products, pharmaceuticals, illicit drugs, personal care products, as well as per- and polyfluoroalkyl substances (PFAS) often end up in the environment and are distributed in different compartments. Human related activities and sewage facilities’ inability to remove them from the wastewater stream seem to be the main sources of contamination of the marine ecosystem. Upon ending up in the natural environment, both biotic and abiotic processes, such as hydrolysis and photolysis, take place, producing transformation products (TPs), suspected to be the cause of even more potent effects compared to parent compounds.

The region of Thessaly, Greece, was severely struck by sequential major storm events named “Daniel” and “Elias”, during the fall of 2023. Approximately 1.5 million tons of water per square kilometer rained down the surrounding area of Pagasitikos Gulf (Aegean Sea, Eastern Mediterranean) each day the phenomena were in effect. Naturally induced environmental change such as these may increase the number of chemicals, which end up in the marine ecosystem and relate to anthropogenic activities, often causing unpredictable damage to indigenous fauna and flora. Many of these compounds reach humans through the food chain and are classified as persistent, bioaccumulative and toxic (PBT).

Aiming to extract as many contaminants as possible from the studied samples, generic sample preparation protocols were applied using multilayer mixed-mode SPE cartridges to enrich the final extracts with thousands of LC-amenable, non-volatile, thermal unstable, semi-polar to polar, organic micropollutants.

The analytes were chromatographically separated using Reversed Phase Liquid Chromatography (RPLC). The chromatographic system was linked to a hybrid Trapped Ion Mobility Spectrometer coupled to High Resolution Mass Spectrometer (TIMS-HRMS). The occurrence of more than 2,000 chemicals from different chemical classes was investigated in the acquired HRMS-data through wide-scope target analysis based on strict identification criteria. TIMS provides an additional dimension of separation, adding increased value of confidence to the identification criteria, minimizing false positive selection, further optimizing wide-scope target screening methodology via HRMS analysis.

Preliminary results indicate the presence of numerous plant protection products in seawater and sediment samples, associated with agricultural activities, such as Azoxystrobin and Atrazine along with their respective TPs: Azoxystrobin acid and 2-hydroxy-atrazine, desethyl-atrazine and desisopropyl-atrazine. Pharmaceutical compounds were also detected in some cases, especially in areas close to wastewater treatment plants, such as Carbamazepine, along with its’ metabolites: 10,11-epoxy-carbamazepine and 10-hydroxy-carbamazepine, findings that could be attributed to reported overflowing of nearby sewage treatment plants, during the flood events. The presence of PFAS is also confirmed, following the detection of compounds such as Perfluorooctanesulfonic acid (PFOS) and Perfluorooctanoic acid (PFOA), possibly linked to the destruction of industrial and port infrastructure.

This work was funded by the Ministry of Development & Investment, National Strategic Reference Framework (NSRF) - Operational Program: “OP Transport Infrastructure, Environment and Sustainable Development”, in the frame of the Monitoring program for the ecological quality of rivers, transitional and coastal waters according to WFD 2000/60/ΕΕ