Occurrence, distribution and risk assessment of organic micropollutants in the Saronikos Gulf, Greece, utilizing LC-TIMS-HRMS

Abstract

This study investigates the occurrence, distribution and ecological risk of emerging contaminants (ECs) and priority pollutants (PPs) in seawater and sediments of the Saronikos Gulf, and Elefsis Bay, Greece, an area continuously impacted by wastewater treatment plant (WWTP) effluents, industrial discharges and maritime traffic. Utilizing novel liquid chromatography tandem ion-mobility spectrometry and high-resolution mass spectrometry the occurrence of more than 4,000 LC-amenable organic micropollutants was investigated through wide-scope target and suspect screening. A total of 171 analytes were detected in marine samples, with pharmaceuticals identified as the most prevalent class (36% in seawater, 41% in sediments) followed by plant protection products (18% in seawater, 27% in sediments). Per- and polyfluoroalkyl substances (PFAS) were also detected in both matrices. Semi-polar ECs with higher molar mass were determined exclusively in sediments near WWTPs, possibly due to their high log P values, reflecting their affinity for particulate matter. Additionally, seawater circulation pattern was found to play a significant role in controlling the spatial distribution of ECs. Comparison with earlier studies in the area suggests a clear shift in pharmaceutical usage by the local population. Risk assessment, based on risk quotient calculations and environmental quality standards (EQS) set by EU legislation, revealed that PFAS exceeded annual average environmental quality standard values in 92% of seawater samples, whereas 20 ECs in seawater and 12 in sediments exceeded predicted no-effect concentrations (PNECs), indicating potential adverse effects on marine biota.