Some lakes are coming off MN's list of polluted waters

Lots of lakes are going onto the polluted list, but a few are coming off.

The Minnesota Pollution Control Agency (MPCA) said it had some good news to report Tuesday: it's going to take some lakes and rivers off the state's list of polluted waters. 

They're recommending that nine bodies of water – including five lakes in the Twin Cities area – be removed from the "impaired waters" list

Then they dropped the other shoe: hundreds of other waters are being added to that list. 

The 618 new listings bring the total number of polluted waters to 2,669. Some of those lakes and rivers have more than one thing polluting them, though. So the total number of "impairments" is over 5,000. 

There's a 60/40 split between healthy/polluted

To be fair, one of the reasons the polluted waters list is expanding so much is because the state is taking a really thorough look at all of its lakes and rivers. 

The MPCA says it's in the middle of a 10-year water quality study that includes all 80 Minnesota watersheds. 

So taking such a comprehensive look is revealing lots of problems or red flags, which are all being added to that list that now has 5,000 things on it. 

But through it all, the agency says, there's one rule of thumb that continues to hold true: about 60 percent of the lakes and rivers in the state are healthy. The other 40 percent are polluted. 

Putting all the sate's waters under a microscope has revealed lots of problems, but through it all that 60-40 ratio has stayed about the same, they say. 

What kind of pollution? 

There are a couple different pollution standards. 

Some water is too dirty to swim in, but fish and underwater bugs can still live in it. 

Other waters are so polluted that nobody lives in them at all. 

Of this year's additions to the polluted list, 201 streams and 23 lakes are in that "can't support aquatic life" category. It's mostly because of nutrients that cause algae and sediment that clouds the water. 

There are 100 streams that scientists now say have too much bacteria for people to swim in safely. Most of them are in the Red River Valley, the MPCA says, where the bacteria could be caused by manure runoff or failing sewer systems. 

In 32 bodies of water the fish have too much mercury for you to eat them. 

The interesting thing there is that most of the mercury in Minnesota's lakes actually comes from the air and the MPCA says 90 percent of it drifts here from other states or countries. 

The recommended changes to Minnesota's impaired waters list won't be final until after a series of November public hearings around the state. The schedule is listed here

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Minnesota's list of polluted waters grows by more than 500

On the bright side, there are 13 lakes that were cleaned up enough to come off the Minnesota Pollution Control Agency's semi-annual list of polluted waterways. On the other hand, more than 500 rivers and lakes were added to that list. There are now more than 3,600 bodies of water that are too polluted for fishing or swimming.