Number of Minnesota waters known to be polluted 1,400

St. Paul (AP) – Extensive testing has pushed the number of
Minnesota lakes and streams known to be polluted to a record

The Minnesota Pollution Control Agency said last week it wants
to add nearly 300 “impairments” to the list, which is updated every
two years.

Altogether, the number of known impairments in Minnesota
waterways is 2,575 because some of them have more than one problem
pollutant, MPCA research scientist Howard Markus said.

The number could grow in coming years. Only about 18 percent of
Minnesota’s lakes and 14 percent of its rivers have been assessed
so far. Of those tested, about 40 percent fail and are listed for
at least one pollutant.

For waterways with impairments, the state can impose pollution
limits that require farmers, businesses, and cities to change their

New pollutants on the inventory are listings for PFOS, a
chemical formerly made by 3M that has been found in fish in 13
metro-area lakes, and acetochlor, a corn herbicide detected in two
southeastern Minnesota rivers.

The MPCA will submit the draft list to the federal Environmental
Protection Agency, but a dispute over acetochlor may delay the

State regulators originally had listed five rivers as impaired
by the herbicide, but dropped three of them after reviewing
evidence from the chemical’s manufacturers that the MPCA’s proposed
water quality standard for acetochlor was too strict.

Dow AgroSciences LLC and Monsanto Co., the two leading
manufacturers of products containing acetochlor, also have
challenged the inclusion of the two remaining river segments on the
list – the Le Sueur River and a short waterway called the Little
Beauford Ditch. The companies said last Thursday that there are
“factual disputes” that need to be corrected in a formal two-day
hearing before the entire list goes to the EPA.

Carla Heyl, an attorney general for the MPCA, said the agency
will recommend that the chemical companies’ petition be denied for
several reasons. She also said any appeal of the state’s list at
this point needs to be filed with the EPA.

Markus said most of Minnesota’s water pollution problems occur
in four areas: fecal coliform bacteria from animal feedlots or
failing septic systems; excessive phosphorus and nitrogen from farm
runoff and sewage plants; mercury from coal-burning power plants,
taconite processing, and other sources; and turbidity or cloudiness
caused by erosion, runoff from fields or construction sites, and

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