PROGRAMME

The occurrence of antibiotics in the environment could lead to the development of antibiotic resistance in bacteria, which could trigger a public health crisis. The occurrence of 676 antibiotics and main transformation products (TPs) was investigated in the effluents of 48 wastewater treatment plants (WWTPs) from 11 countries (Germany, Romania, Serbia, Croatia, Slovenia, Hungary, Slovakia, Czechia, Austria, Cyprus, and Greece) using target and suspect screening. Target screening involved the investigation of antibiotics with 40 reference standards. Suspect screening covered 676 antibiotics retrieved from the NORMAN Substance Database (antibiotic list on NORMAN network). Mass spectrometry fragmentation patterns and retention time index predictions of the studied antibiotics were established for their screening by liquid chromatography – high resolution mass spectrometry using NORMAN Digital Sample Freezing Platform (DSFP). In total, 47 antibiotics were detected in effluent wastewater samples: 32 detected by target screening and 15 additional ones detected by suspect screening. Ecotoxicological risk assessment was performed based on occurrence data and predicted no effect concentration (PNEC). The assessment involved the derivation of frequency of appearance (FoA), frequency of PNEC exceedance (FoE) and extent of PNEC exceedance (EoE). Risk characterization revealed 5 antibiotics of environmental concern (azithromycin, erythromycin, clarithromycin, ofloxacin and ciprofloxacin). The median of daily load of antibiotics to freshwater ecosystems by a WWTP was 0.59 g. The detection of antibiotics in wastewater effluents across countries indicates the widespread presence of antibiotics in the ecosystems of Europe, which may trigger unwanted responses including antibiotic resistance. This requires systematic monitoring and establishment of emission limits in the regulatory context.