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Information bulletin #44

posted Oct 12, 2015, 3:44 PM by Keith Gilbert

PFOS contamination in Lake Johanna
In 2011, Perfluorooctane sulfonate (PFOS) was discovered in fish tissue in Lake Johanna. See this link for more details. Since then, Summer Streets, a chemist from the MPCA, has been trying to locate the source of the chemical.

She is asking the Lake Johanna Improvement Society for help. Specifically, if you have a well that has not been sealed, she would like to take a water sample from your well. As she explains:

I am interested in shallow wells in the surficial aquifer (not bedrock wells), and I prefer active wells, although it may be possible to access and sample old wells if they haven’t been completely filled and sealed.

Here’s a bit of background about the sampling you can share with potentially interested homeowners:

I am looking for 2 suites of contaminants:

Perfluorochemicals, also known as PFCs. The analysis can detect 13 PFCs including PFOS. You may be familiar with these as “Scotchgard” chemicals that have been a concern in MN for a number of years.

Chlorinated paraffins, also known as CPs. These are a very complex suite of chemicals with tens of thousands of potential isomers. Data are reported as short-chain (SCCP), medium-chain (MCCP), long-chain (LCCP), and total CPs. SCCPs have only recently been phased out for future use and are likely still present in current-use products. MCCPs and LCCPs are still being widely used in numerous industrial and consumer applications.

I am interested in these chemicals because Lake Johanna is impaired due to high concentrations of PFOS in fish tissue. There is currently a 1 meal/month fish consumption advisory in the lake. I have been working to find the source of contamination for quite some time, and so far have come up empty. I am hoping these groundwater samples will help me determine a source so we can stop it and improve the lake.

In the process of looking for CPs as part of my other regular work, I had fish tissue from Lake Johanna tested, assuming it would probably be representative of so-called “background” concentrations. I was quite surprised when the results turned up higher-than-expected concentrations of CPs. A second round of sampling confirmed my initial findings. The concentrations of CPs found in fish do not appear to be at a level that is a concern for human health, however, aquatic life appears to be quite sensitive to these chemicals and the levels found so far are a concern.

CPs and PFCs are used in many similar types of industrial applications and products, so, I am hoping that if I find the source of one, I will find the source of both. Getting groundwater samples from around the lake will go a long way toward helping me pinpoint the source, or perhaps in convincing me that the source is not at all related to groundwater. The only way to know for sure is to get enough samples for a thorough analysis.

Please feel free to share this email with anyone in your association that may be interested in allowing access to their wells. Your assistance is greatly appreciated!

Best regards,

Summer Streets
Environmental Chemist
Minnesota Pollution Control Agency
520 Lafayette Rd N, St Paul, MN 55155
(651) 757.2761