Whitewater may be added to list of impaired waters
By Mike KallokStaff Writer
St. Paul - The middle branch of the Whitewater River and four other southern Minnesota rivers likely will be listed as impaired due to the presence of a chemical commonly found in pesticides.
Acetochlor, which is used to control weeds in row crops, has been measured in concentrations that could be harmful to aquatic plants, according to Marvin Hora, Minnesota Pollution Control Agency water assessment manager.
It's the first time the MPCA has requested EPA approval for the listing of a river due to the presence of a 'modern pesticide,' Hora said.
In the past, rivers have been listed as impaired due to the presence of mercury, phosphorus, and bacteria.
Provided the EPA grants approval of the listings, state agencies will begin looking at ways to reduce the amount of acetochlor entering rivers, according to Greg Buzicky, director of pesticide and fertilizer management for the Minnesota Department of Agriculture.
'We work very closely with the PCA in sharing data, and we will be working closely with them on the impaired waters,' Buzicky said.
The MDA has been monitoring surface water for pesticides since 1993, according to Buzicky.
In 2006, pesticide monitoring at different intervals was conducted by the MDA on more than 50 streams and rivers across the state, according to department data.
Both acetochlor and the weed killer atrazine are present in surface water and are listed by the MDA as pesticides of concern.
The two chemicals often are used in conjunction with one another, said Buzicky, who noted that fewer pounds of these chemicals are used per acre by Minnesota farmers than almost all other growers in the Upper Midwest.
Along with education designed to help producers apply the lowest rate of pesticide, farmers are encouraged by the MDA to create filter strips or buffer zones of vegetation to reduce the amount of runoff entering surface water.
According to hydrologist Paul Wotzka, of Weaver, the recommendations are not enforced and crops often are sprayed within 8 feet of trout streams.
Rising demand for ethanol and the nearly ubiquitous use of atrazine and acetochlor for corn production coupled with the geography of southeastern Minnesota add up to what Weaver describes as 'the perfect storm.'
Thin soils, fractured limestone, and the intimate connection of surface and groundwater in the region not only provide ideal habitat for trout, but also provide direct routes for these chemicals to enter the drinking water supply.
Wotzka worked for the Minnesota Department of Agriculture and monitored water on the middle branch of the Whitewater River for nearly 16 years.
He said acetochlor, which was approved for use in 1994, on the condition that less atrazine would be used by farmers, began showing up in water samples as soon as they began testing for it in 1995.
In October, Wotzka left the MDA to work for the MPCA, but was fired in May. He filed a whistle-blower suit in June, claiming the state terminated his employment for wanting to testify at a legislative hearing about the results of his atrazine monitoring and the risk the chemical poses for endocrine disruption in aquatic animals.
According to Hora, the MPCA has evaluated the presence of atrazine in surface water in several areas of the state and has not found levels exceeding safe standards.
Wotzka doesn't agree with those findings, noting that his research showed atrazine to be present in the middle branch of the Whitewater, often at levels exceeding the safe standard for aquatic life.
He said listing the rivers as impaired due to the presence of acetochlor is only a small step, adding that a host of other pesticides, including atrazine, are finding their way into southeastern Minnesota streams and groundwater.
'We've got a chemical soup out there, and the agencies are dealing with this on a chemical-by-chemical basis,' Wotzka said.
It's not too little too late, but it's very little, said Janette Brimmer, legal director for the Minnesota Center for Environmental Advocacy, regarding the proposed impaired river listings.
'We're happy to see it; we've been nagging the PCA to put these on the list for years, as well as others,' Brimmer said.
Levels of both atrazine and acetochlor spike in rivers after rain events.
According to Hora, levels of atrazine have been measured at unsafe levels during these spikes, but when unsustained higher levels are averaged out they fall below criteria for listing water as impaired.
'I would describe what the PCA and Department of Ag are doing is fun with math,' Brimmer said. 'Atrazine spikes have been getting higher and more frequent.'
The EPA classifies acetochlor as a likely human carcinogen, according to Samuel Yamin, a toxicologist with the MCEA.
The MDA has monitored groundwater since 1985, and according to Buzicky, aside from private wells near the site of spills or chemical facilities, no unsafe pesticide levels have been found.