Four Decades of Research on the Swedish Large Lakes Mälaren, Hjälmaren, Vättern and Vänern: The Significance of Monitoring and Remedial Measures for a Sustainable Society

Abstract

The large lakes of Sweden, Mälaren, Hjälmaren, Vättern and Vänern, have been subjected to water-quality monitoring for almost four decades. Physicochemical variables, plankton and benthic invertebrates have been regularly assessed. Hydrological and sediment conditions, macrophytes, fish, primary production, bacteria and attached algae have been periodically investigated. The human impact, including industrial activities, was reflected in excessive amounts of organic matter, nutrients, metals and persistent organic compounds. From the late 1960s all municipal sewage works in the catchments of the lakes were upgraded to the highest technical standard, including chemical precipitation of phosphorus, and phosphorus discharge from the sewage works was thereby reduced by 90–95%. In addition, industries were obliged to restrict discharge of harmful substances. The reactions of the lakes to the remedial measures are discussed as well as the value of various indicators. The studies were instrumental in designing a national lake monitoring program. Additionally, results from large lake monitoring have contributed to the establishment of national water-quality criteria including, physical, chemical, and biological indicators.

Published in

AMBIO: A Journal of the Human Environment
2001, Volume: 30, number: 8, pages: 458-466

SLU Authors

• Willén, Eva

  • Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Environmental Sciences
Oceanography, Hydrology, Water Resources


Publication identifier

DOI: https://doi.org/10.1579/0044-7447-30.8.458

Permanent link to this page (URI)

https://res.slu.se/id/publ/131601