Archive for Friday, June 10, 1994


June 10, 1994


Farmers and water utilities wait as Lawrence researchers track herbicide contamination of drinking water in northeast Kansas.

Carl Flory's corn fields are largely weed free -- just endless rows of luscious green corn plants that follow the man-made terraces and natural rolling contours of otherwise bare brown earth eight miles south of Lawrence.

The weeds have been few and far between each spring on Flory's corn fields since the early 1960s, when Flory -- then working with his father -- started using the chemical herbicide atrazine to kill weeds.

The inexpensive, popular, powerful chemical that has caused tumors in laboratory animals has also seeped into streams and lakes in northeast Kansas and eventually into the lower Kansas River, which supplies drinking water for more than 370,000 people -- including those in Lawrence.

And since 1989, when the U.S. Environmental Protection Agency lowered its safe drinking water standard for atrazine contamination from an annual average of 215 parts per billion to 3 parts per billion, water utilities have been pushing for limits on the chemical's use so they can avoid having to purchase expensive filtering equipment.

"I'd hate to see it go off the market," said Flory, who this year applied about 1 1/2 quarts of atrazine to each of his 400 acres of corn and 100 acres of milo. "It doesn't kill everything, but it sure helps."

Tracking contamination

In 1989 atrazine contamination in the tributaries and waters of Perry Lake, which supplies water for several small Jefferson County communities and which drains into the Kansas River northwest of Lawrence, were higher than the EPA's maximum allowable contaminant level.

In an effort to lower the Perry Lake contamination, the Kansas Board of Agriculture in December 1991 created a Pesticide Management Area for the 1,100-square-mile Delaware River region that drains into Perry Lake.

Initially the pesticide management area imposed few restrictions on atrazine use, but rather asked farmers to voluntarily cut their use and avoid applying the chemical near stream banks and public water supplies. Farmers in the area were also asked to limit the amount of atrazine they used.

The board of agriculture said at the time that if the voluntary measures weren't enough to cut atrazine contamination in drinking water then it would consider mandatory restrictions, as had been recommended all along by a technical advisory panel.

That warning became meaningless in 1992 when the EPA approved nationwide restrictions on atrazine use nearly identical to the voluntary measures in the Delaware River Basin Pesticide Management Area.

However, the PMA was not rendered entirely meaningless. That's because U.S. Geological Survey researchers from Lawrence continued to monitor atrazine levels in the area in what may be the most extensive study ever of the transport of atrazine from farm fields to waterways.

The USGS set up 10 monitoring stations along Delaware River tributaries that automatically sample water when the water rises after a rainfall. That's when runoff and contamination are highest, especially in late spring, when atrazine is typically applied to fields.

The researchers hope not merely to gauge contamination levels in the pesticide management area but to identify the specific tributaries that contribute the most atrazine runoff to Perry Lake. If they can track the runoff then regulators may be able to devise measures to reduce contamination in specific areas while still allowing the herbicide to be used, said Mike Pope, a USGS hydrologist.

"We're basically still trying to get the point across and work with the agricultural community so that we're making a proactive effort here, trying to prevent problems to keep the cities from having to do changes in their water systems," said Dale Lambley, assistant to Kansas Agriculture Secretary Phillip Fishburn.

Cleanup costs

Without reductions in atrazine contamination municipal water companies could face enormous filtering expenses.

Water District No. 1 of Johnson County, which draws drinking water from the Kansas and Missouri rivers for about 300,000 residents in 15 cities, including Shawnee, Lenexa, Overland Park, Merriam, Mission and Leawood, spent $1.2 million in 1991 to install a new treatment system that uses powdered activated carbon to remove atrazine from the water.

Atrazine removal costs the district about $280,000 a year, said Tom Schrempp, the district's assistant director of operations.

And the costs could mount. A more reliable treatment method, which so far hasn't been necessary, could cost the district $50 million, plus $2 million a year to operate, Schrempp said.

"The question is, how much money do we want to spend to treat our drinking water?" said Tim LeTourneau, water systems engineer for the city of Lawrence.

"Everything can be removed from drinking water, one way or another. But, it's risk verses cost. So if we want to spend $500 a month on our water bill to have ultra pure water, then let's have the public step forward and say that's what we want and increase water bills accordingly. It's all kind of relative."

Lawrence has had a powdered activated carbon treatment system for years to control the taste and odor of its water.

"We've had to feed additional dosages of powdered activated carbon to help remove the atrazine concentrations," LeTourneau said. "That's one of the reasons why we wanted to see the pesticide management area work. We are limited to the amount of powdered activated carbon we can physically feed. The chemical itself has its limitations as to how much atrazine it can remove. If atrazine levels increased in the Kansas River we then would have to look at more expensive means of treatment."

In August 1993 the water drawn from the Kansas River for the Lawrence water supply had atrazine contamination of 1 part per billion before treatment, LeTourneau said. Clinton Lake water measured 1.2 parts before treatment.

Samples taken May 19 this year showed levels of 1.3 parts per billion in the Kansas River and 1.2 in Clinton Lake.

The carbon treatment reduces level to well below 1 part per billion. LeTourneau said raw samples from the Kansas River have been as high as 8 parts per billion within the past three years.

Researchers are cautiously optimistic that atrazine contamination in Perry Lake has declined in the past two years. In 1993 atrazine levels just below Perry Dam averaged 1.7 parts per billion, well below the EPA limit. But researchers also say the results are inconclusive because of unusual weather in the years of study. So the study will continue through next spring.

Meanwhile, the herbicide's manufacturer, Ciba Crop Protection Agricultural Group, of Greensboro, N.C., has petitioned to have the maximum allowable contamination level raised to 20 parts per billion.

If not atrazine, then what

For now, atrazine remains an effective, and above all cheap means of killing weeds and increasing yields on Carl Flory's farm. It costs him about $4 to $5 per acre.

"It's been around for a number of years," he said. "I wonder if it's as bad as they say it is. I wouldn't doubt if they could find a trace of just about everything in the water if they wanted to. I'm sure they'll come out with some new chemical, and I'm sure in 10 or 15 years they'll find something wrong with it.

"It's one of those things," he said. "We have to do what we're supposed to do, what we're told, whether we agree with it or not. There have been some changes in farming in the last 35 years and I'm sure there'll be more."

He said if he can't use atrazine he'll use some other chemical to kill his weeds.

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