Freshwater Umbrella News

Two new research reports, launched today, indicate that UK waters are recovering from acid rain

Tuesday November 15th, 2005

Some of the UK's most environmentally sensitive upland lakes and streams are starting to recover from the effects of acid rain. According to new research the amount of acidic sulphur in UK waters has generally halved in the last 15 years. In turn acidity is declining and wildlife is beginning to recuperate.

It is thought that - thanks to emission controls brought in by Government and greater use of natural gas over coal - fish, plants and insects are now starting to return.

Since 1970 there has been an 84% decline in sulphur dioxide emissions (from 3.8 million tonnes to 1 million tonnes in 2002) and a 37% decline in emissions of nitrogen oxides. These gases, along with emissions of ammonia from agriculture, are largely to blame for acid rain.

The wildlife and chemistry of upland lakes and rivers throughout the UK had also been severely affected. Natterjack toads in the south of England may have been lost due to the acidification of their spawning ponds. Salmon and trout fisheries in small Welsh rivers also suffered significant declines.

Ben Bradshaw, Fisheries and Local Environmental Quality Minister, today welcomed the research and highlighted how measures brought in by Government were starting to bear fruit.

It will take time for these sensitive waters to recover from the devastating effects of acid rain. So it is extremely encouraging that today's research suggests that they are starting to recover, he said.

The research shows that the measures we have put into place to control emissions of sulphur dioxide and nitrogen oxides are starting to pay off. The switch from coal to gas in both power generation and in the home, while being mainly for economic reasons, has also meant a lot less pollution. New, strengthened measures - such as the implementation of the Large Combustion Plant Directive - will help ease the situation even further, said Bradsahw.

The report "Future of Britain's Upland Waters", launched today, details the proceedings of a one-day workshop held at UCL in a series of papers. These stress the importance of upland water ecosystems and the threats they face from atmospheric pollutants and changes in climate and land-use.

In particular the report contains a summary of the main findings of 15 years of monitoring as part of the UK Acid Waters Monitoring Network (UK AWMN). The full results of the analysis of the UK AWMN data have recently been published in a special issue of the scientific journal Environmental Pollution.

The UK AWMN is funded by DEFRA and was established in 1988 to study the success of international emissions reductions and their effects. The Network comprises 22 of the most sensitive lakes and streams in the UK, is coordinated by Don Monteith at the Environmental Change Research Centre, UCL, and involves researchers from the Centre for Ecology and Hydrology, Queen Mary, University of London and Fisheries Research Services.

In around half of all sites, native algae and invertebrates are showing signs of recovery. In others, acid-sensitive mosses and other aquatic plants have been found for the first time in fifteen years. And at three of the most acidic sites identified juvenile brown trout have recently been found for the first time since monitoring began.

Other examples of improvement include, the River Etherow in the Pennines which has experienced substantial reductions in biologically toxic Aluminium as levels of acidity have fallen; and the Round Loch of Glenhead, in Galloway and Llyn Llagi in Snowdonia, both with a well documented history of acidification, where stands of aquatic plants absent during acidification have now returned.

University College London's Professor Rick Battarbee said, Wildlife in many of our upland lakes and streams in the UK has been badly affected by acid rain. But following a major decrease in sulphur emissions there are encouraging signs of recovery, with newly-hatched brown trout now re-appearing at the most acidic sites.

However, there is a long way to go. There is a risk that a wetter climate in the uplands in future might offset some of the recovery we are now seeing. Continued careful monitoring at key sites will be essential to assess future responses to these different pressures, said Battarbee.

Ben Bradshaw agreed that more work was needed to clean up UK waters. Unfortunately, today's research does not mean our waters are in the clear, he said. This is an issue without boundaries, so our focus must be on working closely with our European and international partners. We need to put into place effective policies to address the causes of acidity, nitrogen pollution and other forms of trans-boundary air pollution, said Bradshaw.

The Future of Britain's Upland Waters is available online at or from the Defra website

Further information