The pollution in the lake comes from the old paper mill and other adjacent businesses.

At the bottom there is contaminated sea sediment and also a fiber bank of cellulose from papermaking.

But if the lake is to be dredged and the bottom partially covered, it can cost up to SEK 550 million.

- Munksjön flows into Lake Vättern, which is covered with drinking water, and we must protect it, says Emma Willaredt, who is head of department at the county administrative board.

It's a lot of money it's about?

- Yes it is, but dealing with pollution problems is very expensive and difficult and this is a particularly difficult case.

The company that carried out the investigation on behalf of the municipality of Jönköping has come up with four possible measures that would improve the environment in Munksjön to varying degrees.

In the clip above, you get to know more.