Current and Future Emissions of Urban Chemicals into the Aquatic Environment

Urban environments are hot spots for chemical use and emissions and urban aquatic systems are under constant pressure from exposure to chemical mixtures. Chemical emissions and impacts are expected to change in the future due to socio-economic, climate and technological changes. However, the impact of these changes on chemical use and emissions is uncertain. This study therefore investigated how the emissions of chemicals of concern in European urban aquatic systems might evolve in the future due to global changes. A systematic review demonstrated that more than 1100 chemicals, belonging to 19 class categories, have been detected in urban environments around the globe. Comparison of the measured concentrations with ecotoxicological data indicated that 168 of these chemicals pose an unacceptable risk for at least one location and should be regarded as priority chemicals. To determine the current level of risk associated with selected priority chemicals in Europe, two antibiotics and ten metals were monitored in rivers in York (UK), Madrid (Spain) and Olso (Norway) for one year. Results showed that aluminium, zinc, iron, copper, mercury, chromium and the antibiotic clarithromycin all posed an unacceptable risk. To investigate how chemicals emissions might change in the future, a framework was developed to extend the Shared Socio-economic Pathway approach, an approach used in climate change forecasting, to forecast changes in chemical emissions in the future. Following, pilot-testing with insecticidal products and antidepressants, the framework was used to forecast antibiotics emission in European freshwater systems in 2050. This resulted in a number of different future emission scenarios characterised by either an increase or decrease in antibiotic emissions depending on the pathway. Overall, the thesis has demonstrated that chemical pollutants do pose an unacceptable risk to European urban aquatic environment. It illustrates how emissions of chemicals are likely to increase or decrease in the future depending on the pathways that society follows. The findings will be invaluable to decision makers involved in the risk assessment and management of chemical products and the natural environment.