Currently, there is uncertainty about emissions of pharmaceuticals into larger closed ecosystems that are at risk such as the Baltic Sea. There is an increasing need for selecting the right strategies on advanced wastewater treatment. This study analysed 35 pharmaceuticals and iodinated X-ray contrast media in effluents from 82 WWTPs across Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland and Sweden. Data from Finland and Denmark were compared to predict effluent concentrations estimated using different levels of refinement. The concentrations predicted by the Total Residue Approach, as proposed by the European Medicines Agency, correlated with R2 of 0.18 and 0.031 for Denmark and Finland, respectively and the predicted data were significantly higher than the measured ones. These correlations improved substantially to 0.72 and 0.74 after adjusting for estimated human excretion rates and further to R² = 0.91 and 0.78 with the inclusion of removal rates in WWTPs. Temporal analysis of compound variations in a closely monitored WWTP showed minimal fluctuation over days and weeks for most compounds but revealed weekly shifts in iodinated X-ray contrast media due to emergency-only operations at X-ray clinics during weekends and an abrupt seasonal change for gabapentin, thus indicating towards limited predictability for these compounds. Environmental ImplicationThis focusses on emissions of pharmaceuticals by analyzing the effluents from 82 wastewater treatment plants (WWTPs) across eight countries. The data derived from this study illustrates that the real-world concentrations of pharmaceuticals contrasts with those predicted by conventional models based on pharmaceutical sales data only. The findings underscore the limitations of current predictive models and demonstrates how these methodologies can be refined by incorporating human pharmaceutical excretion/metabolization as well as removal in wastewater treatment plants to more accurately forecast pharmaceutical levels in aquatic environments. Beyond the scientific advancement of the field, this study provides support for environmental regulators and policymakers in developing and prioritizing more effective regulations and treatments to mitigate the environmental impact of pharmaceutical residues by removing them from wastewater or other mitigation options.