Most of Sweden’s lakes and streams are in relatively good health despite the impact of human activities. Only a few are absolutely pristine, however.
On 1 July 2011, the responsibility for most issues related to the freshwater environment, among them, eutrophication, was taken over by the Swedish Agency for Marine and Water Management (SwAM). Issues related to acidification and environmental pollutants are still in the remit of the Swedish EPA.
The Swedish Agency for Marine and Water Management
The state of the freshwater environment is monitored
The number of acidified lakes and streams in Sweden is steadily declining thanks to the rising pH-levels in rain and snow. However, it takes a long time for plants and animals to return to formerly acidified waters. The load of toxic pollutants has also declined, as shown by analysis of perch.
Environmental monitoring shows that our lake waters are becoming browner because the inflow of humic compounds (organic soil material) has increased. Humic compounds bind many toxic pollutants, which may account in part for the reduced accumulation of toxins in fish and other organisms. The increasing humic concentration in our waters may be an effect of climate change and greatly increased water flows.
The status of plants and animals in lakes and streams is primarily affected by:
- physical impacts, changes in lake and stream morphology
- acidification
- eutrophication
- the introduction of alien organisms
- inflows of heavy metals, and toxic or oxygen-depleting substances