International co-operative programme on assessment and monitoring of acidification of rivers and lakes

Abstract

The International Co-operative Programme on Assessment and Monitoring of Acidification in Rivers and Lakes has been designed to establish the degree and geographic extent of acidification of surface waters. Further, to collect information in order to evaluate dose-response relationships and to define long-term trends and variations in aquatic chemistry and biota attributable to atmospheric pollution, particularly to acidic deposition. Twenty countries of Europe, Russia and North America have representatives in the Programme. Data from more then 200 sites in 16 countries are available in the database. Sites included in the programme are monitored by each country individually, although the monitoring methods used have been standardised across participants and intercalibration studies are completed each year. The programme base delivered data, reports and results for use to the Working Group on Effects of the ECE/UN. The programme Centre and the Programme database are located at the Norwegian Institute for Water Research (NIVA). The unique possibility to evaluate water quality in catchments across boundaries has been performed based on available data of the programme data base. Long-term trend analysis on the ICP dataset is the first attempt, as far as we know, to trey to discover regional patterns both in Europe and North America in long-term changes in surface water chemistry, due to changes in deposition. Decreases in surface water sulphate and calcium concentration were common among European sites, in both river and lake sites. Decreases in nitrate concentrations were observed in many of the European sites. Decreases in suffice water sulphate predominated at the US sites although these were not accompanied by any specific trend patterns in other variables. At the Canadian sites, decreases in sulphate were common and were accompanied by in creases in pH. Concomitant increases in alkalinity were noted in some of these sites but not all.