Freshwater ecosystems are today facing multiple pressures from a cocktail of pollutants. They include chemicals, microplastics, pharmaceuticals, invasive species and land management practices. Consequently, the majority of UK rivers fail to have good ecological status. Only 14 per cent of waterways in England, 46 per cent in Wales, 50 per cent in Scotland, and 31 per cent in Northern Ireland made the grade.
Poor water quality can result in the loss of aquatic invertebrates and fish. It can threaten the structure and stability of the aquatic food chain. In other cases, it can be dangerous for bathing and lead to enhanced drinking water treatment needs and costs.
The Natural Environment Research Council and Defra have awarded researchers funding. The funding came from the £8.4 million Understanding changes in quality of the UK freshwaters programme to:
- investigate how pollutants enter, leave and interact with rivers and supporting ecosystems
- determine how the movement of pollutants will be modified with changes in the water cycle
- create better tools to monitor and measure pollution.
The £1.6 million University of Bristol-led project will study how livestock farming practices affect UK water quality.
Livestock farming is the dominant farming type and source of organic matter pollution in UK freshwaters. About 10 million cattle and more than 30 million sheep are on 10 million hectares of grassland. It represents more than half (57%) of all agricultural land in the UK.
Penny Johnes, Professor of Biogeochemistry at the university’s School of Geographical Sciences, said: “When livestock excreta are flushed to waters, it drives changes in their physical, chemical and ecological quality and function. This material contains inorganic nutrient contaminants typically included in routine water quality monitoring programmes across the UK and many other compounds that are not being monitored.
What does this research mean for freshwater ecosystems?
“These include nutrient-rich organic matter, pathogens, pharmaceuticals and hormones. They are likely to drive significant damage to freshwater ecosystems. They also present a persistent problem for recreational water use, fisheries and shellfisheries and drinking water in livestock farming catchments.”
Climate change-induced increases in water temperature and alterations in flow regimes are also accelerating the biological processing of this material in freshwaters. At the same time, increased rainfall may overwhelm on-farm storage capacity, thwarting efforts to reduce the effects of livestock farming on UK freshwaters.
“The project will deliver a new understanding of how these stressors interact to drive changes in UK water quality in livestock-dominated catchments,” said Johnes.
The field sites comprise the Conwy, Bristol Avon and 50 further catchments across livestock farming regions in Wales, Scotland, Northern Ireland, and the north and west of England.
“Through this innovative programme, we will develop cutting-edge environmental science focussed on improving UK freshwater quality. The programme will help ensure that our rivers and other waterways are more resilient to future climate and land-use change.”
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