About seventy drugs and about thirty other chemical substances that are difficult to break down have been analyzed around and in Lake Vänern, Lake Vättern and Lake Mälaren, which together supply three million Swedes with drinking water.
25 of the critical substances were found in more than half of the samples in the Great Lakes.
For example, the content of the hormone drug estradiol was above the environmental quality standard in almost half of the samples in all three lakes.
In three surrounding watercourses, the analgesic and environmentally hazardous drug diclofenac was measured above the norm, which can be said to indicate what nature can tolerate.
PFAS substances
The chemical PFOS, which is considered to be one of the most dangerous so-called PFAS substances, occurs at levels that exceed the environmental quality standard in all three largest lakes, their watercourses according to the report.
PFOS has been used in fire foam but also in textiles, for example.
- The PFAS substances are a problem because it takes so long to break them down and they are enriched in fish.
This is a problem for Lake Vättern, which has such a long turnover time.
The water remains for 60 years before it flows into the Motala stream.
Does it affect people?
What the report shows is what pollutants are present.
However, it remains to be seen how it affects, for example, fish and humans.
- The next step for us is to look at drug residues in fish to see how much they take up of the drug residues and what effects it can have, says Friederike Ermold.
The critical substances are also found in drinking water, but today the concentrations are so low that they do not pose a danger.
The treatment plant
The three large lakes Vänern, Vättern and Mälaren together supply about three million Swedes with drinking water.
For a year, SLU, together with the three lakes' water management associations, has carried out extensive sampling, not only in the lakes but also in watercourses, waterworks and treatment plants.
The treatment plants today are not able to purify drug residues.
- Drug treatment is definitely something we need to look at, says Friederike Ermold.
An experiment will soon begin in Alingsås where new methods of pure medicine will be tried.