ACIDIFICATION OF SURFACE WATERS IN NORTHERN SWEDEN CURRENT STATUS – FUTURE – COUNTERMEASURES
Recent studies show that anthropogenic acid surges provide the major acidification problem for lakes and watercourses in northern Sweden. Anthropogenic acid episodes may occur in around 20-40 % of all watercourses and in around 15-30 % of all lakes. Anthropogenic acidification throughout the year is a lesser problem. Predictions for the future using mathematical models indicate that current reduction planes for acid emission in European countries will still cause a successive deterioration of surface water quality in northern Sweden during the next 20 years. A reduction of acid emissions of 60-80 % would be enough to stop deterioration of surface waters being anthropogenically acidified throughout the year, while the number of surface waters where anthropogenic acid surges occur may be reduced by 20-40 %. Analysis of limed lakes in northern Sweden indicate that liming have been successful in most occasions, but may have been unnecessary for a fairly large number of lakes.