Last week, the Minnesota Pollution Control Agency announced it had found elevated amounts of industrial chemicals called PFAS in the flesh of fish from the St. Croix River. The substances are toxic, hurting child development, They originate from sources like 3M’s closed landfills in Oakdale.
Agency scientists have now shared more details about just how much PFAS they found. The average amount in the fish sampled from the river was 32 nanogram per gram, said Miranda Nichols of the Water Assessment Section.
Anything above 0.37 ng/g is considered impaired and possibly harmful.
Sampling efforts included taking fish from Taylors Falls all the way down to Prescott. Researchers collected 31 fish of five species: smallmouth bass, largemouth bass, bluegill, common carp, and freshwater drum, reported MPCA scientist Bruce Monson. The lowest level of PFAS detected was 1 ng/g — still above the threshold. The highest level was 295 ng/g in a smallmouth bass.
PFAS are particular problems for pregnant and nursing women and children. The chemicals interfere in neurological development. Much remains unknown about their effects on human health and the environment. They are often called “forever chemicals” because they do not break down in the environment.
The designation of the lower St. Croix River as impaired for fish consumption is part of a process to regularly update the state’s list as required by the Clean Water Act. This year marked a significant addition to waters contaminated by PFAS. The substances were used for products like Scotchgard and many other industrial purposes.
While it may change in the future, general guidance is now to limit meals of St. Croix River fish to once per month. That’s the same recommendation for white bass, buffalo, and channel catfish because of mercury and PCBs.
The MPCA is accepting written comments on the draft 2022 list of impaired waters through 4:30 p.m. on Friday, Jan. 7, 2022. After the comment period and any changes to the list based on public input, the state will submit the draft list, and the comments and responses, to the U.S. Environmental Protection Agency for final approval. Details on how to comment.
Public information meetings
Attend an online public information meeting via Webex.
- Statewide assessments, including discussion of PFOS in fish tissue and sulfate in wild rice production waters
Thursday, Dec. 9, 2 p.m.
Join the meeting
Meeting number (access code): 2486 889 4793
Meeting password: RjVaYfgu847
- Central Minnesota regional meeting, including Sauk, Mississippi River – St. Cloud, and Lower St. Croix river watersheds
Monday, Dec. 20, 2 p.m.
Join the meeting
Meeting number (access code): 2489 358 6002
Meeting password: PpetMP4ex39