Acidification in the Lake District on the decline

Dr Tipping compared pH levels in 1999 with those in 1998 and 1971-73. Samples of rain and river water collected in the Duddon catchment in 1999 gave significantly higher pH values than in previous years. The team also found evidence that the invertebrate populations are starting to recover. The paper concluded: “These findings are consistent with a long-term response to the gradual decline in acid deposition, mainly of sulphur.”

The group has also published results showing a local decline in sulphate deposition, which may be related to the decline of heavy industry in the Midlands or even as far away as Northern Ireland. Sulphate deposition by rain is closely related to the burning of coal for electricity at power stations and other energy-intensive industries.

Although these results show that acidification is on the decline in the Lake District, further studies are needed to establish if there is a similar improvement across the UK as a whole.

The DETR is soon to publish a report produced by University College London, which will detail changes in pH and biodiversity over the past 10 years at 2O sites around the UK.

Dr Tipping said: “Our findings in the Lake District are probably the first to show the reversal of acidification and biological recovery in the UK but they are not unique in Europe, as similar results have also been found in Norway.”