MARSHALL - About 20 area residents gathered at the Marshall-Lyon County Library on Thursday evening to learn more about the Minnesota Department of Agriculture's (MDA) developing program to control ground water contamination by nitrate fertilizers.
Nitrates are chemicals that accumulate in the soil from agricultural fertilizers, manure, septic systems and airborne nitrogen compounds given off by industry and automobiles. Nitrates dissolve easily and percolate into ground water and are thought to be linked to low blood oxygen levels in infants.
Ground water is defined as at the Health Risk Limit (HRL) when nitrate levels reach 10 parts per million. Currently, 6 percent of the state's wells exceed the HRL, mostly in the Central Sands region and in Washington and Dakota counties. Two townships in Lyon County and one each in Lincoln and Yellow Medicine counties have wells with nitrate levels that exceed the HRL.
"About 54 percent of our drinking water comes from public groundwater wells," said Annie Felix-Gerth, nitrogen fertilizer management plan coordinator for MDA. "Twenty percent comes from private wells, and 26 percent from surface water sources."
According to MDA studies, nitrate removal from municipal water systems, using either a reverse osmosis filtration system or drilling new wells to blend unaffected water with existing supplies, imposes an estimated $2 million to $3 million in upfront costs.
The Department of Agriculture first drew up a plan in 1990. The present project is being developed to update the plans and procedures in the light of 20 years' experience.
"We wanted to look at all the things that have changed, and the experience we've gained," Felix-Gerth said.
What has been learned from experience are protocols for testing, best management practices (BMP) to assure the most efficient use of nitrates by crops so less goes into the ground water and remediation measures, such as planting strips of nitrogen-hungry plants such as alfalfa alongside receiving streams.
Don Stoddard, assistant director of the Pesticide and Fertilizer Management Division of the MDA, outlined the four phases of the proposed Nitrogen Fertilizer Management Program.
The first step is preventing nitrates from entering the ground water in the first place.
"We know this is not possible," Stoddard said. "The goal is to minimize it through a phased approach assessing and prioritizing areas, involving local farmers and consideration for alternative management tools."
Stoddard said the MDA's goal is to encourage voluntary BMPs through locally- recruited advisory boards and consider regulation at phases three and four only as a last resort.
"We'll start by identifying, who are the biggest farmers, active groups, crop advisers?" Felix-Gerth said. "In Phase one and two, we'll start initiating contacts in at-risk townships."
The MDA is seeking comments and feedback through local meetings and on its website through Nov. 2. Implementation of the plan is expected to begin early next year.
Doug Albin, director of the Minnesota Corn Research and Promotion Council, urged careful consideration of all factors involved.
"I appreciate the idea they're going to take the time to research it before imposing on communities without considering the costs imposed," Albin said. "Farmers are trying, we need to have some guidance not based on emotion but based on research."