Last year, more than 700 people -- most of them pickup-driving backyard gardeners -- showed up for the city of Lawrence's second annual compost giveaway, hauling off 4,000 tons of recycled bounty.
"It was boon to any gardener," said Lawrence master gardener Marilyn Hull. "Here was all this free material that otherwise you'd have to pay for, and you could take all you wanted. It was a great deal."
Not this year. City officials canceled the giveaway after learning the compost contained Clopyralid, a lawn care herbicide that's harmful to flowers and tomato plants.
"Knowing what we know now, we've chosen not to give it away," said Mollie Mangerich, operations supervisor at the city's Waste Reduction and Recycling Division.
That has left gardeners and city officials wondering what to do with this year's crop of contaminated compost and how to avoid a replay of the problem in coming years. And the discovery may solve some gardeners' unexplained failures over the past few years -- the city has learned last year's compost was even more contaminated.
Mangerich said she would spend the coming months educating the public about Clopyralid, a common ingredient in many lawn and turf herbicides.
"We need to get people to understand that if they use a product that contains Clopyralid, they shouldn't bag their clippings for curbside pickup," Mangerich said, "because that's how it's getting in the compost. It's in the clippings."
The city's compost is made from more than 9,000 tons of leaves and grass clippings collected throughout the spring, summer and fall.
Tests found Clopyralid in this year's compost at a rate of 55 parts per billion. Rates exceeding 10 parts per billion can be harmful to garden-type plants, mainly tomatoes, peas and broadleaf flowers like sunflowers.
Last year's compost tested at 72 parts per billion, Mangerich said. But the sample wasn't submitted and the results weren't known until after the compost had been given away.
The latest testing was part of a Kansas Department of Health and Environment sampling in response to Clopyralid being detected in composting operations in California, Washington and Pennsylvania.
Nearly the worst
"We sent (Kansas State University) 34 samples from 27 (composting) facilities," said Ken Powell, environmental scientist at KDHE's Bureau of Waste Management. "Clopyralid was found in 17 of the samples."
Lawrence's 72 parts per billion, he said, was the second highest in the state last year. Powell declined to say which Kansas city's compost crop contained more.
The presence of the herbicide may explain a few things, said Bruce Chladny, extension agent for horticulture at the Douglas County office of K-State Extension.
"I've gotten calls from people who've done everything right -- proper watering, good plant selection, mulching -- and who said they composted, and then for some unexplained reason they started having problems," Chladny said. "I never questioned the compost. I should have. Maybe that's what it was."
Plans call for crews to put some of the compost on city-owned grassy areas.
|To reduce the transfer of Clopyralid to compost stock, city officials recommend that residents:¢ Not use herbicide products containing Clopyralid on residential lawns.¢ Instruct your lawn-care professional to not use Clopyralid-containing herbicide products on your property.¢ Do not set out grass clippings that have been treated with products containing Clopyralid for city collection and composting.¢ Do not compost materials in your back yard that have been treated with a Clopyralid-containing herbicide.¢ If you wish to use products containing Clopyralid, leave the grass clippings on the lawn after mowing.|
"There'll be a lot left over," said Bob Yoos, solid waste manager for the city. "We haven't decided what we'll do with the rest of it. We may just let it sit and see if the Clopyralid degrades to a point where we can give it away in the spring."
No way to know
So far, no one has figured out how much of the contamination is linked to over-the-counter herbicide sales and how much is tied to commercial lawn or turf treatments.
Commercial applicators say they're not to blame:
- "We've never used it," said Scott Waisner, general manager at Preferred Lawn Service and Landscaping.
- "We used to use it, but we don't anymore," said Larry Ryan, owner of Ryan Lawn and Tree. "If it causes a problem, we don't want anything to do it with it."
|Twenty-eight herbicide products containing the active ingredient Clopyralid are registered for use in Kansas and distributed for agricultural use and for use on residential lawns. They are available through chemical supply and retail stores:¢ 16-4-8 with Millennium Ultra Herbicide¢ Accent Gold Herbicide¢ Accent Gold WDG¢ Battleship¢ Chaser Ultra¢ Confront¢ Curtail¢ Curtail M¢ Hornet¢ Hornet WDG¢ Lesco Momentum Premium Selective Herbicide #062479¢ Lontrel Turf and Ornamental¢ Millennium Ultra Plus¢ Millennium Ultra Weed & Feed 20-5-10¢ Momentum Weed & Feed 0-0-7¢ Momentum Weed & Feed 21-0-12¢ Preen N Green Lawns¢ Redeem R&P;¢ Riverdale Millennium Ultra Selective Herbicide¢ Riverdale Trupower TM Selective Herbicide¢ Stinger¢ Strike 3 Ultra¢ Tee Time 18-5-9 With Millennium Ultra Herbicide¢ Transline¢ Weed & Feed¢ Weed & Feed 32-3-5¢ Weed & Feed with Millennium Ultra HJE¢ Winter Weed & Feed 24-4-14|
Chladny said there was no way to know for sure.
"There are so many guys out there who spray (commercially); it's not just lawn-service people," he said. "It would be impossible to sort it all out."
By next spring, few if any over-the-counter lawn herbicides will contain Clopyralid.
"We've amended our labels so that Clopyralid will no longer be used for residential lawn care," said Tim Maniscalo, spokesman for Dow AgroSciences, which manufactures Clopyralid.
The herbicide still will be available for uses that do not involve bagging grass clippings. Those include weed control on golf courses.
"Clopyralid is an excellent product," Maniscalo said. "It's not the problem -- it's not a problem if you're not going to bag the clippings."
He insisted that Clopyralid was not harmful to people or pets.
KDHE's Powell said Lawrence officials did the "smart thing" in calling off this year's giveaway.
"They know what they've got and they're working on it," he said. "That's exactly what they should be doing. They can go ahead and put it on their parks with no problem at all and, in the meantime, be educating the public about Clopyralid."