Our single largest environmental remedial measure in Swedish freshwaters is liming the waters to reduce damage by acidification. It comprises significant monitoring by hydrochemical and biological sampling. The monitoring is conducted both regionally and nationally.
Regional liming effect monitoring
The regional monitoring of liming effects include both chemical and biological sampling. The chemical analysis primarily aims to assess whether the calcium doses are appropriate to fulfill the liming objectives. Therefore, it is usually limited to sampling during the most acid conditions, and only comprises a few hydrochemical parameters, typically pH, alkalinity and some measure of water colour or organic material content.
National liming effect monitoring
The national monitoring of liming effects commenced in 2007 with the target lake inventory. About 3 000 limed so-called target lakes were analysed with respect to chemical composition, during the autumns in 2007 and 2008. The sampling also comprised about 1 800 unlimed reference lakes. The inventory aimed to provide a basis for assessment of acidification of the limed lakes.
During 2010 to 2013, one sixth of all target lakes were sampled each year with sampling in the autumn and subsequent spring, so that half of the lakes have four samples. During 2010 to 2016, a corresponding sampling program was implemented for limed target watercourses and unlimed reference watercourses.
Read more about liming effect monitoring and liming on our page about IKEU (Integrated Studies of the Effects of Liming Acidified Waters, ISELAW).