State officials have toughened up standards — again — for a chemical made by the 3M Co. found in drinking water.
Officials with the Minnesota Department of Health on Wednesday said that the safe level for the chemical needs to be slashed almost in half, because of new scientific research.
The new standards will have no effect on drinking water in Washington County cities, because levels already have been sharply reduced.
However, officials said that six privately-owned wells now have pollution levels above the new standards. The owners of those wells will be notified, and provided with an alternative water supply.
The chemical is PFOS, or perfluorooctane sulfonate. The health department’s new limit for PFOS is 15 parts per trillion, a reduction of almost half from the previous guideline.
In 2017, state health officials cut the acceptable limits for PFOS to 27 parts per trillion — less than half the previously-accepted level of 70 parts per trillion.
The health department also set a “health-based advisory” for PFHxS, or perfluorohexane sulfonic acid, of 47 parts per trillion. Previously, the state officials did not have information about this chemical, and set guidelines based on other chemicals.
3M manufactured the chemicals starting in the 1940s, for use in non-stick cookware and stain repellent. It legally disposed of the chemicals in dumpsites in Washington County.
In 2004, traces of the chemicals were discovered in underground plumes of water around the dumpsites, impacting the drinking water of Lake Elmo, Woodbury, Oakdale and Cottage Grove.
Large doses of the chemicals cause thyroid problems, birth defects and cancer in mice, but the chemicals never have been proven to adversely impact human health in the levels found in Washington County.
According to James Kelly, manager of environmental surveillance and assessment, the new values are a small adjustment, but they provide additional protection for human health.
“These changes may seem minor but they are part of our ongoing commitment to protect the affected communities,” Kelly said.
*Original article online at https://www.twincities.com/2019/04/03/minnesota-health-officials-cut-safety-level-of-3m-pollutant-in-half/