A controversial iron treatment in a Chisago County lake can continue, a Minnesota Pollution Control Agency panel said on Tuesday.
For several years, the Rush Lake Improvement Association has dumped tons of powdered iron into the lake. The stated goal is to improve water quality by binding phosphorus to the iron.
Audubon Minnesota and other groups asked for an environmental review. They worry about possible effects onfish and birds living in the lake. They contend that the real reason for the treatment is to reduce curly-leaf pondweed, which would require a permit.
Steve McComas runs Blue Water Science, the firm that arranges the iron treatment. He says the effect on the invasive plant is coincidental.
"In our studies, we sample aquatic plants where we add the iron; in those cases, curly-leaf is often reduced in density; it's still present, but reduced in density," McComas said.
Because the treatment is experimental, the MPCA Citizens Board decided the project doesn't need an environmental review.
Wild River Audubon president Sue Leaf is disappointed in the MPCA decision.
"I like to think of my state agency as being very concerned with good science, and in this case good science isn't being done," Leaf said. "All the hallmarks of good science aren't there — especially once you have data that you publish that data and allow the scientific community to comment on it, and there was no element of that in that room, whatsoever."
The MPCA Board will require Blue Water Science to report its results next year.