BioCycle May 2004, Vol. 45, No. 5, p. 52
While analyses in the Pacific Northwest show reduced average herbicide amounts, concerns are still voiced.
According to recent studies in Washington and Oregon, restrictions on the use of the herbicide clopyralid have, on average, significantly reduced compost contamination levels in those states. Concern continues, however, among composters and end users, both in the Pacific Northwest and around the country.
On March 26, 2004, the Washington State Department of Agriculture (WSDA) reported an average 80 percent reduction of clopyralid levels in commercial compost between 2001 and 2002, followed by an additional nine percent reduction in 2003. And on April 7, 2004 the Oregon Department of Agriculture (ODA) reported an overall average decrease of 47 percent between 2002 and 2003 in levels of clopyralid in compost from 12 operations tested in their state. Two of the facilities tested in Oregon showed an increase in clopyralid contamination. Utilizing the GC/MS analytical method, in the fall of 2003 the Oregon Department of Environmental Quality found clopyralid levels ranging from 4.3 to 37 ppb in compost samples tested (versus a range of 6.3 to 94.2 ppb in 12 samples taken in October 2002).
In eastern Washington, the average level of clopyralid in compost dropped from 169.4 ppb to 26.7 ppb between 2001 to 2002. WSDA’s most recent tests, however, showed average clopyralid levels in the eastern, primarily agricultural part of the state actually increased in 2003. That increase was caused primarily by one facility that went from an average 5.7 ppb in 2002 to an average 75 ppb in 2003 as the result of a batch of compost made with livestock bedding, grass and hay feedstocks that showed clopyralid at 260 ppb. At a second eastern Washington facility, although it had an overall decline, individual batches of compost made with grass clippings showed clopyralid levels of 87 and 66 ppb.
The contamination problem first surfaced in eastern Washington in 1999 when crop failures in Spokane and Pullman were traced to compost containing clopyralid. Testing revealed similar problems at composting operations in Oregon, California, Pennsylvania and New Jersey, primarily from residential lawn clippings. To protect the compost industry, the states of Washington, Oregon and California adopted rules prohibiting the use of clopyralid on residential and commercial lawns (except parks and golf courses), but no restrictions were placed on agricultural uses. The manufacturer, Dow AgroSciences, responded by amending the product’s label to more clearly state that grass clippings from turf treated with clopyralid should not be used as mulch or be diverted to commercial composting operations “in the growing season of application.” (See sidebar for article coverage in BioCycle on clopyralid and compost.)
Despite increased restrictions on its use, clopyralid is still impacting the compost industry around the country. In response to citizen complaints about failed gardens, in the fall of 2003 the city of Lawrence, Kansas, announced the cancellation of compost distribution from its municipal yard trimmings facility after tests showed clopyralid levels of 52 ppb. The Lawrence results led the Kansas Department of Health and Environment to test 27 composting facilities across the state, with 17 of those sites testing positive for clopyralid contamination.
Concern about improper use of clopyralid prompted an alert from the New Jersey Department of Environmental Protection to pesticide applicators on March 31, 2004 regarding potential contamination from grass clippings removed from turf areas treated with clopyralid. According to the New Jersey Pesticide Control Program, the relabeling of clopyralid “has put the burden on pesticide applicators to ensure that these clippings are not used for compost.” The letter goes on to state, “It also puts the burden on composting facilities, farmers and others who recycle organic materials to be sure not to accept grass clippings that contain residues of clopyralid, a difficult task.”
Jeff Gage, a board member of the Washington Organic Recycling Council, notes that while average clopyralid levels in western Washington dropped from 80.9 ppb in 2001 to 1.1 ppb in 2003, the increase in eastern Washington between 2002 and 2003 – from an average of 26.7 to 29.4 ppb – means the situation persists. “The testing data shows welcome reductions as an effect of the ban on feedstocks coming from lawn clippings and other municipally generated green materials in western Washington,” says Gage. “Unfortunately, the agricultural compost feedstocks tested in eastern Washington containing hay, straw and manure do not provide the same good news. As a result, the problem cannot be considered solved for Washington state.”
He adds that Washington chose to “encourage voluntary, farmer-directed exclusions of their agricultural wastes from entering compost facilities rather than an outright ban. Due to unreliable voluntary controls, agricultural waste-based products from eastern Washington are reaping the same problem faced by western Washington, where the state took decisive action on yard debris feedstocks.”
Chrys Ostrander, an organic farmer in eastern Washington, echoed this concern. Ostrander was quoted in the Capital Press as predicting that as long as clopyralid is used in large-scale agriculture, there will be outbreaks of crop loss due to contamination.
Others maintain clopyralid isn’t the problem that many fear. Cliff Weed, WSDA Pesticide Compliance Manager, attributed some crop losses experienced over the past few years to operator error. “Part of the problem was people weren’t using compost properly,” Weed told the Capital Press. “You don’t grow plants in pure compost,” he said. “It is intended to amend the soil when blended with the existing soil.”
Marti Roberts-Pillon of the Oregon Department of Environmental Quality says that in its testing, the state was unable to get enough samples to make any statement about clopyralid levels in manure and animal bedding. For further details, go to: www.deq.state.or.us/wmc/solwaste/clopyralid.html