New product could remove common herbicide from drinking waterby Stephanie Hemphill, Minnesota Public Radio
St. Paul, Minn. — Two University of Minnesota graduates have come up with a product to remove the common herbicide atrazine from drinking water.
Corn farmers across the Midwest use atrazine to kill weeds, but it contaminates groundwater, and exposure to it can cause a variety of health problems, according to some animal studies.
The new product involves taking bacteria and attaching them to a filter inserted in the water supply. The bacteria then consume the atrazine.
The young entrepreneurs are capitalizing on 15 years worth of research by their professors. They do much of their work in the Biotechnology Resource Center, in the basement of a building on the University of Minnesota's St. Paul campus.
Stainless steel tanks line the walls. They're fermentation tanks, where bacteria and other small creatures are fed their favorite foods so they'll reproduce a lot. This is where the idea began, according to Alex Johansson, the chief scientist at NewWater, a tiny business with big plans to clean up atrazine in drinking water.
Johansson is a chemist who just graduated from the university last year. Researchers in this lab introduced him to a bacterium -- part of a group called arthrobacter -- that eats atrazine.
"The organism is very effective. It can consume its weight in atrazine every two minutes," said Johansson. "So every two minutes, 50 grams of organism can eat 50 grams of atrazine, at its peak efficiency."
Atrazine is a commonly used herbicide throughout the Midwest, and it's highly effective at killing weeds in cornfields. But it migrates into waterways, and studies have linked it to sexual abnormalities in frogs and fish. In some animal studies, it's been linked to liver, kidney, and heart damage.
Some cities in the farm belt -- not in Minnesota -- have spikes of atrazine in their drinking water supplies that far exceed the health limit set by the Environmental Protection Agency. The EPA is currently reviewing new research on atrazine, and may consider tighter restrictions.
Johansson and his partner Joe Mullenbach, who also graduated from the U last year, are working with a couple of local manufacturing firms to design a filter that will exploit the special appetite of this bacterium.
"In rudimentary terms, we glue the cells to the inside of your Brita water filter," said Johansson. "It's not glue, it's an immobilization method, but we take the organisms and glue them to the walls [of the filter] and then it functions."
It doesn't just capture the atrazine, as carbon filters do. It uses an enzyme to break down the atrazine into harmless substances.
The partners have licensed three patents owned by the university. One of the patents is for a technique to kill the bacterium, but allow it to retain the enzyme.
That's useful in case the firm decides to use genetically modified versions of the bacterium. The modified organisms are more efficient, but they would probably face more resistance from regulators who would have to approve the system.
The concept has been tested in the lab, and also in the field. Ten years ago, a truck accidentally dumped atrazine on a field in South Dakota. One of the lab's main researchers, professor Larry Wackett, heard about the accident and offered the bacteria he'd been working with in the lab. He says after the bacteria had eaten their fill of atrazine, the EPA certified the soil as clean.
"This was about 1,000 pounds of atrazine that had been spilled in the soil, and it was all cleaned up," said Wackett. "That was a good demonstration that something much larger than what you have in the laboratory could work."
But what about the rivers and lakes, where atrazine may be harming frogs and fish? Wackett says it's possible in the future the entrepreneurs could apply the same techniques there.
"I think from their business scouting, they find that that wasn't a big business opportunity, so as a new company they couldn't focus on that initially," said Wackett. "People have higher priority than frogs, so that's just the way it is."
There's more work to be done, including conducting tests at larger scales and obtaining government approvals. The firm hopes to have a product to introduce to the market in two years.
- All Things Considered, 07/29/2010, 5:24 p.m.