Critical loads and their exceedances for ICP-Waters sites (ICP Waters report 44/1998)

Abstract

The International Co-operative Programme on Assessment and Monitoring of Acidification of Rivers and Lakes (ICP Waters) is designed to assess, on a regional basis, the degree and geographical extent of acidification of surface waters. We report here an assessment of critical loads and their exceedances of sulphur and nitrogen acidity for the 92 ICP-sites (72 in Europe and 20 in North America). At 46% of the European sites the critical loads of acidity are less than 50 meq/m²/yr, and 68% of the sites have critical loads less than 100 meq/m²/yr. The corresponding figures for the North American sites are 40 and 75%, respectively. Comparing the critical loads with the nitrogen and sulphur depositions in 1990, the current reduction plans (CRP) and maximum feasible reductions (MFR) scenarios in 2010, it was found that of the 72 European sites 51 were exceeded in 1990, 32 will still be exceeded in 2010 under the current reduction plans, and only two at maximum feasible reductions. Apparently, the sensitivity of surface waters to acidification in parts of Europe has not received proper attention.