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Pesticide residues in grass clippings raise concerns

Pesticide residues in grass clippings raise concerns

Joyner, Joel

MANATTAN, Kan. – Over a billion pounds of pesticides are sold in the United States annually. Though an estimated 70 percent are applied for use on agricultural foods and products, golf courses often are targeted when pesticide use issues develop.

While federal legislation is currently focused on regulating pesticide usage at public schools, some golf course superintendents and courses are taking a proactive approach on the issue, particularly with grass clippings, before the government sprays them with new regulations.

One of the main subjects being addressed is the proper disposal of turfgrass clippings that have been treated with pesticides. “Normally, if clippings are scattered over existing turf areas, the pesticides degrade relatively quickly,” said James Snow, national director of the USGA Green Section in Far hills, N.J. “The one thing not to do is dump clippings into ponds or streams.”

RECYCLE AND REUSE

For the most part, golf courses return clippings to the soil to be recycled by soil microbes, according to Todd Lowe, USGA agronomist in Hobe Sound, Fla. “Clippings are removed from greens only on most courses, but the topic of clipping disposal is an especially important issue around equipment washing facilities.”

More and more facilities are installing systems that separate clippings and recycle and reuse the water following a filtration and treatment process. “The clippings can then be transported to a compost heap to recycle nutrients back to the environment,” said Lowe.

Dave Gourlay, course manager here at the Colbert Hills Golf Course, makes use of Landa’s Waterstax wash-water treatment system to reduce potential runoff of pesticides when equipment is cleaned at the facility.

“We have a contained wash pad station that was installed when the course was built,” said Gourlay. “The Waterstax unit uses a process called bioremediation to treat the wash water.”

After equipment used on the course is washed, the system removes dirt and turfgrass clippings. “The wash water is then treated with a solution of microbes that break down the waste into carbon dioxide and water,” Gourlay said.

The water enters a separate tank and is further cleansed with aeration and additional treatment before it’s made available for reuse. “It’s capable of treating a thousand gallons a day at a rate of 15 gallons per minute,” Gourlay said. “The grass clippings are either dried and redistributed to the course or composted.”

PERSISTENCE OF PESTICIDES

Gerald Stephenson and colleagues at the University of Guelph in Guelph, Ontario, Canada, published a study on the persistence of pesticides in turfgrass clippings this summer. Stephenson recommends not to collect clippings for composting for about four weeks following pesticide treatments.

The research focused on 2,4-D, Mecoprop, Dicamba, Chlorpyrifos and Chlorothalonil in controlled “once-loaded” and “multiple– loaded” compost scenarios.

“Basically, we treated a large area of turfgrass with these different pesticides, and then we harvested a large quantity and mixed clippings in roughly a 60/40 ratio with tree leaves. We placed the mixture in home composters to monitor the disappearance of pesticides over time,” said Stephenson.

The researchers harvested one study the day after pesticide treatments were applied, and multiple-loaded studies were harvested at week intervals. “In about four to five weeks, the pesticide residues were not detectable in the multiple-loaded scenarios,” Stephenson said.

“In the once-loaded scenario, although the pesticides were disappearing, the dry weight of the compost was decreasing as well,” he said. “The concentration of the pesticides didn’t change.”

CHANGING CULTURAL PRACTICE

Superintendent Rob Brown at the Martindale Country Club in Auburn, Maine, used to compost clippings at the facility. “We weren’t under any restrictions to change our practice at the course, it just seemed the sensible thing to do,” he said. “About three years, we stopped composting grass clippings altogether and decided to leave them on the course and in our rough areas.”

For Brown, environmental awareness and responsibility prompted his pro active measure toward changing the cultural practice at the course.

Copyright United Publications, Inc. Nov 2001

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