Kalkningens effekt och spridning - Uppföljning och utvärdering av kalkning och försurning i Ulricehamns kommun

Sammanfattning: Acidification was one of the biggest environmental issues during the 20th centaury, especially in Sweden since acidic emissions from other regions ended up in the ground and water here. In this study, data from several lakes in Ulricehamn Municipality was analysed with consideration of acidification. Liming has been carried out in three lakes, Surströmmasjön, Vallsjön and Trehörningen, since the 1980s to counteract the consequences of acidification. The effects of liming were evaluated in terms of pH and alkalinity. Moreover, six other lakes and a few streams have also been tested throughout the years, some of which are positioned downstream from the limed lakes. The results show a significant difference of the mean pH for all limed lakes before and after liming started, furthermore the effects have spread to another lake in the case of Vallsjön. It is possible that the same goes for Surströmmasjön, although this cannot be said for certain without more data prior to the liming. In this study, I show that the positive effects are most abundant in Vallsjön, however a significant increase in pH and alkalinity can also be seen in Trehörningen all throughout the testing period. As for the lakes that has not been limed and which are not positioned downstream from a limed lake, no significant increase in pH has occurred even though the deposition of acid emissions has decreased greatly since testing began. Here I discuss the impact of forestry, which could have slowed down the recovery since the majority of the lakes’ drainage areas consist of forest. In the future, the impact of forestry on acidification will continue to increase and it is therefore important to plan acidification efforts accordingly.