New research shows that beavers remove lots of pollutants from creeks when building their dams. In a new study, scientists found that a single family of beavers remove high levels of sediment, nitrogen and phosphorus from water that flowed through a 2.5 hectare enclosure in the UK. The sediment contained high concentrations of nitrogen and phosphorus, which are nutrients known to create problems for wildlife in rivers and streams and which also need to be removed from human water supplies to meet drinking-quality standards. The study suggest that beavers should be reintroduced into the wild to help clean up polluted rivers.