Fate and consequences of emerging contaminants in the aquatic environment

Water quality in the UK has now become a priority area of concern as freshwater resources and habitats are under threat from various forms of chemical pollution from multiple sources. Human activities have resulted in the release of large volumes of contaminants into the aquatic environment. One of these groups are known as contaminants of emerging concern (CECs), these refer to substances that are often not controlled or monitored in the environment, and even at low concentrations may be harmful to human health or the environment.  CECs cover a diverse range of both synthetic and natural contaminants with wide-ranging properties, including per- and polyfluoroalkyl substances (PFAS) or ‘forever chemicals’; pesticides, fungicides and herbicides; pharmaceuticals (antibiotics and veterinary medicines) and tyre compounds. One of the main pathways CECs enter the aquatic environment is from water recycling centre (WRC) treated discharges. Traditional WRC processes were not developed to remove CECs from water, resulting in these often being present in treated effluent from WRCs. Currently, little is known about how these chemical mixtures behave and the impacts they can potentially have on aquatic ecosystems. This project will aim to elucidate the impact of these polar chemical mixtures on macroinvertebrate communities in freshwater rivers downstream of WRC discharges. The project will consist of 6 key objectives: (1) The student will collaborate with the Environment Agency (EA), Rivers Trust and water utility companies to assemble emerging contaminant data in water and sediment and to inform other objectives of specific CECs to investigate. (2) environmental monitoring of emerging contaminants up/downstream of several WRCs. Monitoring will be undertaken using the Chemcatcher passive sampler for surface water and accredited techniques for sediment sampling. (3) Further development of monitoring and analytical techniques (e.g. liquid chromatography time-of-flight mass spectrometry) for the analysis of contaminants to ascertain the chemical profile. (4) These data will inform experimental investigation into their fate and consequences at environmentally relevant concentrations using a set of semi-natural mesocosms at the River Laboratory facility in Dorset. (5) The project will aim to interpret (using statistical packages) the links between contaminants and macroinvertebrate biodiversity at several sites on the River Avon (Hampshire/Wiltshire, UK) and its tributaries. (6) Source apportionment and modelling of the fate and migration of emerging contaminants in selected catchments development of risk ranking tools aligned to PNEC and PNECRs for essential contaminants.