The impact of nitrogen deposition on upland surface waters in Great Britain: a regional assessment of nitrate leaching.

A national dataset of water chemistry collected for critical loads mapping is used to make a regional assessment of surface water nitrate concentrations in Great Britain. The primary data are dominated by high concentrations in lowland regions Where N inputs are dominated by non-atmospheric sources. Land cover data are used to screen out sites with potential catchment sources of N, allowing the evaluation of nitrate leaching due to atmospheric deposition alone. In the screened dataset several upland regions show elevated nitrate concentrations, notably Wales, the Pennines, Cumbria, Galloway and the Cairngorms, and there is a clear relationship between surface water nitrate and total N deposition.