Water quality refers to the biological, chemical and physical makeup of the water. There are always natural changes in water quality, but industrialisation, population growth, climate change and land-use change have meant more pollutants are entering water systems than ever before. These pollutants alter entire ecosystems and present a danger to human health.

This pollution can be very sudden and dramatic - the BP oil spill made headlines for months. Other pollution, however, is sometimes harder to spot. Nitrogen and phosphorous, for example, quietly enter the environment as by-products of industrial processes. The resulting nutrient-rich water system can actually be harmful for aquatic life, with algae using up all the oxygen and creating ‘dead zones’.  

There is also the financial cost and the toll on human health. Nitrogen pollution alone costs Europe an estimated £60-280 billion per year, and about 10 million Europeans drink water with unsafe levels of nitrate.

CEH work on water quality


Monitoring sites

Research facilities

Clatto reservoir on a sunny day
Assessing failure to control cyanobacteria using Phoslock®
Bassenthwaite Lake and surrounding countryside
Redressing the extinction of vendace
Man holding a brown trout caught at Loch Leven
OpenNESS project: Loch Leven case study
A river in April
Estimates the ecological health of new running water sites
A digital data entry system to capture and store River Habitat Survey data in the field
Balbiania investiens species of algae. Photo: Dr Chris Carter
The list now contains about 5500 species of algae
Working on Loch Leven
The data and infrastructure to improve understanding of ecological processes and environmental change impacts
Predicts soil moisture and crop success in salinity-prone soils
Sediment from Loch Flemington
Helping lake managers diagnose water quality problems effectively and develop suitable restoration strategies
Boats on Derwent Water
Providing insights into how and why lakes respond to environmental change
Clatto reservoir on a sunny day
Providing the evidence for water managers to implement lake restoration programmes
Graph showing epilimnetic inorganic carbon changes in Loch Lomond
Demonstrating high quality and frequent lake measurements