Now the cylinders that Gustaf Olsson found at Turelund's parking lot in the nature reserve have been identified.
They were found to come from treatment plants and to be harmful to the environment.
Gustaf Olsson is a trustee for the foundation that owns the land.
He suspects that the waste has been dumped on the site by someone who wants to avoid paying for the handling.
- I get angry and disappointed that people behave this way, he says.
Lying in unknown liquid
The plastic cylinders can, among other things, come from a private treatment plant or a car wash.
However, it is unclear what kind of liquid the cylinders were in.
The police are now investigating environmental crimes.
- The liquid in which they have been lying can be very toxic, and if you tip this into a ditch that is full of water, it goes without saying that such things can go into the groundwater.
It is dangerous for the environment, says police officer Bo Wickström.
The police currently have no suspects, but hope to receive tips from the public.
Unclear responsibility
The next step is for the land on the site to be cleaned up.
But who will carry out the cleanup remains to be seen.
- Knivsta municipality, which helps with the cleaning here, I thought would take care of it, but they seem to think that it is the landowner's responsibility, which is strange since it is a place that is open to the public.
According to Johan Glad, environmental inspector at Knivsta municipality, it is the property owner who must take care of the cleanup if the person who dumped the waste is not found.
- The municipality does not have a formal responsibility for the remediation measure, we have to demand that it be remedied, he says.
In the clip: See the potentially hazardous waste and hear more about what happens next.