美環保署擬禁止食物殘留「好年冬」殺蟲劑

Due to "considerable risks" of damage to human health and the environment associated with the pesticide carbofuran, the U.S. Environmental Protection Agency is revoking the regulations that allow carbofuran residues in food.

EPA's carbofuran tolerance revocation proposal will be published for public comment on July 30, 2008.
Carbofuran is an N-methyl carbamate insecticide and nematicide registered to control pests in soil and on leaves in a variety of field, fruit, and vegetable crops. No residential uses are registered.

EPA has concluded that dietary, worker, and ecological risks are of concern for all uses of carbofuran. All products containing carbofuran generally cause "unreasonable adverse effects on humans and the environment and do not meet safety standards," and therefore are ineligible for reregistration. When the revocation process is completed, the legal residue limits for carbofuran on food will be reduced to zero.

Carbofuran is a white crystalline solid with a slightly phenolic odor. A broad spectrum insecticide, it is sprayed directly onto soil and plants just after emergence to control beetles, nematodes and rootworm.

The greatest use of carbofuran is on alfalfa and rice, with turf and grapes making up most of the remainder. Earlier uses were primarily on corn crops.

When people are exposed to carbofuran for a short period of time, the EPA has found the chemical to potentially cause headache, sweating, nausea, diarrhea, chest pains, blurred vision, anxiety and general muscular weakness. These effects are reversible, the agency said. Long-term exposure to carbofuran has the potential to cause damage to the nervous and reproductive systems, said the EPA.

Trade names and synonyms for carbofuran are: Niagara 10242, Furadan 4F or 3G, Brifur, Crisfuran, Chinufur, Curaterr, Yaltox, Pillarfuran, and Kenofuran. It is most commonly marketed under the trade name Furadan, by the publicly traded chemical company FMC Corporation.

Even though carbofuran is used on a small percentage of the U.S. food supply and therefore the likelihood of exposure through food is low, EPA says tests have identified "risks that that do not meet our rigorous food safety standards." EPA is cancelling the pesticide registration, which will address the risks to pesticide applicators and birds in treated fields.

Carbofuran enters surface water as a result of runoff from treated fields and enters ground water by leaching of treated crops. The EPA's estimates show that up to two million birds were killed each year by carbofuran before it was banned for all but emergency uses.

FMC Corporation said in a statement Friday that it "believes strongly that carbofuran residue on food does not pose a threat to human health."

FMC has proposed a revised product label retaining uses of five crops where there are no viable alternatives for critical pest control. "Dietary and aggregate risks to carbofuran are acceptable when the best available science is used, contrary to the exaggerated risks as reported by EPA," said John Cummings, North America regulatory manager, FMC Agricultural Products Group.

If released to soil or water, carbofuran is broken down by reactive chemicals and microbes, particularly in alkaline conditions. Carbofuran may leach in many soils, as has been seen in the detection of carbofuran in sandy aquifers in New York and Wisconsin, the EPA said.

The regulation for carbofuran became effective in 1992. Between 1993 and 1995, the EPA required water suppliers to collect water samples every three months for a year and analyze them to find out if carbofuran is present above 0.9 parts per billion, ppb. If it is present above this level, the system had to continue to monitor this contaminant.

If contaminant levels are found to be consistently above the maximum contaminant level, water suppliers have had to reduce the amount of carbofuran using granular activated charcoal.

As part of this effort, EPA is also releasing its response to the peer review conducted by the independent Scientific Advisory Panel and the agency's response to the U.S. Department of Agriculture's comments on the effect of the cancellation of carbofuran on the agricultural economy.

The USDA says that, despite the limited use of carbofuran in most agricultural situations, the pesticide is economically important and some uses, at least, qualify for reregistration.

The USDA claims that carbofuran "is the only feasible post-emergent rescue treatment" for corn rootworm if other options fail, including varieties bioengineered for insect resistance such as Bt corn. Without a rescue treatment, the USDA asserts that grower losses could be as high as $1,000 per acre.

But the EPA does not agree, saying, "Even at the lower current usage, carbofuran use continues to result in serious adverse wildlife incidents, and significant water contamination. For example, a recent incident in 2006 included the deaths of 2,200 birds fiom carbofuran use in a sunflower field in Colorado. Similarly an incident in 2000 included the deaths of 800-1,200 snow geese and ducks following exposure to alfalfa in fields treated with flowable carbofuran.

EPA says reported incidents likely represent only a small fraction of the adverse incidents that are in fact occurring. The agency points out that kills are not likely to be noticed in agricultural environments, which are generally away from human activity.

EPA will accept public comments on the proposed tolerance revocation for 60 days. To find out more, click here. http://www.epa.gov/pesticides/reregistration/carbofuran/carbofuran_noic.htm