Research highlights:

• Developed high-resolution monitoring systems to detect nutrient pollution events and improve water quality management.

• Created predictive models to simulate nutrient flux.

• Informed UK government policy, including the Environment Bill 2021 and Defra's farming rules for water.

• Contributed to international initiatives addressing nutrient pollution.

Nutrient pollution of inland and coastal water systems caused by agricultural practices, sewage discharge and fossil fuel emissions is a growing global threat – contributing to biodiversity loss, harmful algal blooms and water toxicity. The consequences for ecosystems and human health are severe.  

Researchers at the University of Bristol have led groundbreaking studies to quantify and mitigate this problem that have influenced policy and practices on a national and international scale.

Novel approaches and breakthrough findings

Humanity’s disruption of global nutrient cycles is so great that researchers at the Stockholm Resilience Centre have identified the nutrients nitrogen and phosphorus as two of the most pressing threats to planetary stability.  

Bristol’s response to this and other threats has included the development of novel approaches, including new high-resolution monitoring techniques, innovative analytical methods to determine the full range of nutrient contaminants, and powerful digital models that simulate the rates of nutrient flux to waters across the whole of the UK.  

This has enabled team of researchers including Professor Penny Johnes, Professor Jim Freer, Dr Charlotte Lloyd and Dr Gemma Coxon  to determine the  scale and complexity of the nutrient challenge in different UK water systems, including the first spatially accurate simulation of nutrient flux at a 4km2 scale. 

In addition the team has successfully identified the environmental factors controlling the rates and scale of this flux, the pathways by which pollution is transported from land to water, and the importance of organic and particulate nutrient fractions as key contributors to ecosystem damage.  

Influence on practice and policy  

These critical findings have helped to shift perspectives in several important areas – helping to optimise targeting of mitigation measures for specific farming and landscape types, for example, and  providing robust advice and practical solutions that are directly influencing water quality policy and practice.  

In the UK, this has involved collaborations with bodies including Defra, the Environment Agency, Natural England, Natural Resources Wales and water companies. Bristol’s work has also fed directly into UK government policy and practice, informing the House of Commons Audit Committee’s Nitrates Inquiry (2018) and the setting of targets for Water and Biodiversity under the Environment Bill 2021. 

The work has also influenced a range of key reports and policy documents, including Defra’s farming rules for water and advice on nutrient management for agriculture, 

Wider impact 

Beyond the UK, Bristol’s work has contributed to international policy development. The team has advised the United Nations Economic Commission for Europe’s Task Force for Reactive Nitrogen, plus Environment Ministers of the OECD, feeding into their report on Human Acceleration of the Nitrogen Cycle which called for international action to control nitrogen pollution. 

The team is now actively developing new techniques to sense, sample and secure evidence on the behaviours of contaminants in the environment. It is also investigating emerging contaminants in nutrient-enriched waters, including microplastics, pharmaceuticals and organic compounds to address their ecosystem impacts.