The International Cooperative Programme on Assessment and Monitoring Effects of Air Pollution on Rivers and Lakes (ICP Waters)

ICP Waters was established under the United Nations Economic Commission for Europe’s Convention on Long-Range Transboundary Air Pollution (LRTAP) in 1985, when it was recognized that acidification of freshwater systems provided some of the earliest evidence of the damage caused by sulphur emissions.

The monitoring programme is designed to assess, on a regional basis, the degree and geographical extent of acidification of surface waters. The data collected should provide information on exposure/response relationships under different conditions and correlate changes in acid deposition with the physical, chemical and biological status of lakes and streams.
Switzerland joined the Programme in 2000 and is represented by the Cantone Ticino.

Trend analyses of the data reveal that sulphate concentrations decreased and alkalinity increased significantly in most studied lakes. Base cation and nitrate trends are mostly insignificant.
Seasonal variations of the same parameters were analyzed for three Alpine rivers. Seasonal variations of alkalinity, base cation and sulphate concentrations correlate negatively with the river discharge, while a positive correlation was found for the concentrations of dissolved aluminium. In both lakes and rivers macroinvertebrates were utilized as bioindicators for the level of acidification. Applying the evaluation system proposed by Braukmann and Biss (2004) for rivers, acidification classes corre- sponding well with the measured river pH values were obtained.



Dr. Sandra Steingruber,