Analytical and mathematical assessment of emerging pollutants fate in a river system

The fate of several emerging pollutants in a Greek river system was assessed through analytical measurements and mathematical modelling. Target compounds selected in this study consist of five endocrine disrupting chemicals and four non-steroidal anti-inflammatory drugs. Two sampling campaigns were implemented to assess target compounds concentrations along the river system during dry period. Furthermore a mathematical model was developed in order to simulate the spatial distribution of target compounds concentration. The mathematical model describes several abiotic and biotic processes (sorption, photodegradation, biodegradation, biotransformation) in order to account for the removal of target compounds. Following sensitivity analysis, the model was calibrated and validated against measured values. Environmental risk assessment was performed based on both analytical measurements and simulation results. Uncertainty analysis was also conducted by applying Monte Carlo technique. According to the results the simulation data matched very satisfactorily with the analytical measurements, thus confirming the main experimental observations showing that the primary removal mechanism for the photo-sensitive chemicals is photodegradation, the latter being mostly influenced by weather conditions and river general quality characteristics (e.g. chlorophyll, turbidity). Model results demonstrate a gradual increase of uncertainty from the upstream to the downstream of the river system for all target compounds.