On Monday, Nov. 8, the Minnesota Pollution Control Agency released a draft list of lakes, rivers and streams to be added to the state’s impaired waters list in 2022. Included are six water bodies in Washington County that have recently been found to have high levels of perfluorinated alkylated substances, also known as the “forever chemical.” The affected waters include Clear Lake (City of Forest Lake), Tanners Lake (Oakdale), Eagle Point wetland and H.J. Brown Pond (Lake Elmo Park Reserve), and the St. Croix River/Lake St. Croix from Taylors Falls to Prescott.

The journey of PFAS into our local waterways began in the 1950s and ‘60s when 3M began making Scotchguard, nonstick coatings, and fire-fighting foams. The company disposed of manufacturing waste in landfills on Hwy 14 in Oakdale and near Lake Jane in Lake Elmo, as well as at two smaller sites in Woodbury and Cottage Grove.

Over time, the chemicals leached deep into the ground and contaminated aquifers used as a source of drinking water for municipal and private wells in southern Washington County. The MPCA first discovered the groundwater contamination in 2002 and has been continuously working with 3M, local communities, and the Minnesota Department of Health ever since to ensure that east metro residents have safe drinking water.

The groundwater contamination plume has been gradually spreading eastward for decades, but recently, the MPCA determined that PFAS has been accumulating in some lakes and streams in the east metro as well. Three years ago, the MDH issued a fish consumption advisory for Lake Elmo, after measuring high levels of perfluorooctane sulfonic acid, a specific type of PFAS, in fish from that lake. At the time, MDH noted that fish in other nearby water bodies likely had PFOS levels as high, or higher, than what was found in Lake Elmo. 

Now, after years of slow-moving travel, the “forever chemical” has finally reached the St. Croix River as well. The proposed new listing for Lake St. Croix is based on site-specific criteria of 0.37 parts per billion PFOS in fish tissue. Because fish are mobile and able to travel both up and down river, the impairment will apply to the entire length of the Lower St. Croix River, south of the Taylors Falls dam. The river is still considered safe for swimming and recreation but there will be a fish consumption advisory. 

Finding high levels of PFOS in Clear Lake this year was somewhat of a surprise because the City of Forest Lake is well outside of the area affected by 3M’s chemical disposal. However, the airport and several industrial sites located within the Clear Lake watershed are potential sources of pollution. Outside of the east metro area, the MPCA has also found high levels of PFOS in Winona Lake in Alexandria; Wild Rice Lake and Fish Lake Flowage in St. Louis County; and Lake of the Isles, Bde Maka Ska and Harriet Lakes in Minneapolis. In fact, if the MPCA’s proposed changes are approved, there will be a total of 26 water bodies in Minnesota listed as impaired due to PFOS. 

Scientists are still not entirely sure what the long term health effects of PFAS may be. In some studies, higher levels of PFAS in a person’s body were associated with higher cholesterol, changes to liver function, reduced immune response, thyroid disease, and increased kidney and testicular cancer. The latest information also indicates that fetuses and infants are more vulnerable to the chemicals. 


To learn more:

 MPCA info meeting about statewide assessments, including PFOS in fish tissue and sulfate in wild rice production waters: Thursday, Dec. 9, 2 p.m.

(minnesota.webex.com | Meeting number: 2486 889 4793 | Password: RjVaYfgu847)

 Impaired Waters List: www.pca.state.mn.us/water/minnesotas-impaired-waters-list (draft list will be on public notice until Jan. 7, 2022) 

 Minnesota’s PFAS Blueprint: www.pca.state.mn.us/waste/minnesotas-pfas-blueprint 

 Fish Consumption Guidelines: www.health.state.mn.us/communities/environment/fish 

Angie Hong is an educator for East Metro Water. Follow her on TikTok @mnnature_awesomeness or contact her at 952-261-9599 or angie.hong@mnwcd.org. 

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