Monitoring, Modelling And Mitigating Pollution Impacts In A Changing World: Science And Tools For Tomorrow's Rivers

For centuries, human activities have impacted our rivers by shifting the sources and combinations of physical, biological and chemical drivers and pressures. However, our understanding of their impact on ecosystems has been limited by viewing each in isolation and not considering their combined effects. Significant reductions in some regulated pollutants (such as nitrogen and phosphorus) have been achieved in recent decades. However, even with these improvements, we are witnessing declining water quality of our rivers, and the resulting loss of freshwater species and biota. The picture that we see is made evermore complex by the increasing numbers of different types of emerging contaminants of concern (e.g. pharmaceuticals, pesticides, illicit drugs, micro plastics etc.). This means that our freshwater species are being challenged by a bewildering combination of pollutant cocktails (mixtures) whose effects are poorly understood. At the same time, climate-change driven shifts in water quantity (more frequent floods, longer periods of low flow) and warming waters are expected not only to be influencing the function, physiology, abundance and biological timings of freshwater ecological communities directly, but also the delivery and potential toxicity of these cocktails respectively. It is not simply the water pathway that we need to consider, but also the re-mobilisation of contaminants and the changing patterns of exposure that potentially magnify the effects on biota (i.e. organism sensitivity). Our wastewater systems and combined sewer overflows transport these emerging pollutants from our cities and towns into our freshwater environment. Increasing urbanisation and changes in rainfall intensity and its seasonality, different catchment processes all have the potential to increase inputs of these emerging contaminants to the environment and freshwater species that live there.

Substantial knowledge gaps remain around the effects of hydro-climatic and land use changes in combination with the different mixtures of chemicals on freshwater species. Our research will address these gaps by embracing the digital revolution through innovative technologies and transformative data analytics to deliver a step change in our knowledge and understanding. Our approach has three strands. The first will turn a spotlight on a typical catchment encompassing rural to urban land uses through rigorous investigations that will deliver high temporal resolution data. This will provide new understanding of acute/event-based impacts on freshwater ecosystems. Secondly, we will use national scale datasets and cutting edge data analytics tools to investigate the impacts of longer-term exposure to pollutant cocktails across the UK on water quality and ecosystem health. This will provide new understanding of chronic/long term impacts on freshwater ecosystems. Thirdly, we will integrate our new evidence base and understanding into a risk-based probabilistic model. The model will allow the exploration of the relationships between environmental change, declining river quality, multiple pollutants and ecosystem impacts. Our research will develop the evidence base to understand changing pollutant sources, delivery pathways and the environmental tolerances and boundaries within which organisms can thrive and flourish (i.e. the ecosystem safe space).

Together, MOT4Rivers will inform priorities for policy, regulation and investment to design cost effective programmes of measures to promote and enhance sustainable freshwater ecosystems under a changing climate.