Trends in surface water chemistry in acidified areas in Europe and North America from 1990 to 2008
Garmo, Øyvind Aaberg; Skjelkvåle, Brit Lisa; de Wit, Heleen; Colombo, Luca; Curtis, Chris; Fölster, Jens; Hoffmann, Andreas; Hruška, Jakub; Høgåsen, Tore; Jeffries, Dean S.; Keller, W. Bill; Krám, Pavel; Majer, Vladimir; Monteith, Don T.; Paterson, Andrew M.; Rogora, Michela; Rzychon, Dorota; Steingruber, Sandra; Stoddard, John L.; Vuorenmaa, Jussi; Worsztynowicz, Adam
Journal article, Peer reviewed
Accepted version
Date
2014Metadata
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Abstract
Acidification of lakes and rivers is still an environmental concern despite reduced emissions of acidifying compounds. We analysed trends in surface water chemistry of 173 acid-sensitive sites from 12 regions in Europe and North America. In 11 of 12 regions, non-marine sulphate (SO4*) declined significantly between 1990 and 2008 (−15 to −59 %). In contrast, regional and temporal trends in nitrate were smaller and less uniform. In 11 of 12 regions, chemical recovery was demonstrated in the form of positive trends in pH and/or alkalinity and/or acid neutralising capacity (ANC). The positive trends in these indicators of chemical recovery were regionally and temporally less distinct than the decline in SO4* and tended to flatten after 1999. From an ecological perspective, the chemical quality of surface waters in acid-sensitive areas in these regions has clearly improved as a consequence of emission abatement strategies, paving the way for some biological recovery.