Advertisement

The Banned Pesticide in our Soil

FEATUREThe Banned Pesticide in Our Soil © JIM REED/GETTY IMAGES BY ALISON MCCOOK For years, commercial growers have been using methyl bromide to strip their soil of pathogens that impede plant growth. Colorless, odorless, cheap to make (often formed as a byproduct of other bromide manufacturing processes) and relatively easy to use, methyl

By | January 1, 2006

FEATURE
The Banned Pesticide in Our Soil
The Banned Pesticide in Our Soil. In the 1990s, the world agreed to stop fumigating with methyl bromide. So why are so many US farmers still using it?
© JIM REED/GETTY IMAGES

For years, commercial growers have been using methyl bromide to strip their soil of pathogens that impede plant growth. Colorless, odorless, cheap to make (often formed as a byproduct of other bromide manufacturing processes) and relatively easy to use, methyl bromide is an incredibly effective fumigant, whose tiny molecules disperse quickly and efficiently throughout the soil. It wipes out the vast majority of soil pests so well that when it was introduced, farmers practically abandoned all other options. They simply inject the gas 30 to 60 centimeters below the soil surface, often planting a few days later.

"A lot of energy and effort has gone into defending CUEs [critical use exemptions] rather than implementing alternatives."

Perfect? No. Unfortunately, the reasons that methyl bromide works so well also account for its harmful effects. The US Environmental Protection Agency (EPA) estimates that the chemical spreads so easily that up to 95% of the methyl bromide injected into soil eventually makes its way into the atmosphere. There, in high concentrations, it can cause a wide range of health effects, such as failure of the central nervous and respiratory systems. A 2003 study by the National Cancer Institute of male pesticide applicators found that those who handled methyl bromide had a higher risk of prostate cancer.

The bigger problem with methyl bromide is the damage it causes high above our heads, where its splintered bromine atoms help destroy the ozone layer. If growers continue to use the chemical, as they do in large quantities in the United States, methyl bromide could be responsible for as much as 15% of future ozone depletion, according to the EPA. Despite these risks, and a global agreement to ban the chemical, some say US growers want to greedily hold on to methyl bromide because it works so well at a relatively low cost. Now, growers who successfully operate without methyl bromide say they have been threatened by other growers to keep silent. "There's never been an issue as big as this," says Donald Dickson of the University of Florida (UF) at Gainesville, who's studied pesticides for 35 years.

A BAN AND A SEARCH

In 1997, world leaders met in Montreal on the occasion of the Montreal Protocol and decided to stop using the chemical gradually, with the goal of a complete phase-out by industrialized nations by 2005. Developing nations would follow suit by 2015. Scientists began efforts to create a substitute for methyl bromide that works equally well but is less toxic, work that was familiar to a branch of the US government's Agricultural Research Service ARS). Since 1993, me ARS has spent more than $170 million looking for a suitable replacement for the chemical king.

No product has emerged, however, that is as widely endorsed as methyl bromide, and after years of scientific investigations, US growers are still using an estimated 19,000 metric tons of methyl bromide every year, according to the EPA. In 2003, methyl bromide was the fourth most commonly used pesticide among california growers. In that state alone, growers applied more than 3,300 metric tons of the chemical to more than 22,000 hectares of land. The United States recently submitted a request to the United Nations, currently under review, to continue its use of nearly 30% of the methyl bromide used in 1991, a total of 7,400 metric tons, in 2007 alone. (see chart below.)

CRITICAL USE EXEMPTIONS FOR METHYL BROMIDE IN 2005
CUEs granted by the Montreal Protocol (MP)
European Community Total uses granted by MP Total prodn/
imports granted by MP
Belgium 59,794 (kg) 59,824 (kg)
France 474,635 474,635
Germany 45,250 45,250
Greece 227,280 227,280
Italy 2,298,225 2,298,225
Netherlands 120 120
Poland 44,100 44,100
Portugal 50,000 50,000
Spain 1,059,000 1,059,000
UK 134,408 134,330
Source: MP data from reports of Meetings of the Parties (UNEP). *CUE = Critical use exemption

Other countries Total uses granted by MP Total prodn/
imports granted by MP
Australia 146,600 (kg) 146,900 (kg)
Canada 61,792 61,840
Israel 1,089,306 1,074,000
Japan 748,000 748,000
New Zealand 50,000 40,500
Switzerland 8,700 8,700
USA 9,552,879 7,659,000

MP total 16,050,089 14,031,704
US as % of total: 60% 55%
Total minus US: 6,497,210 6,372,704

In contrast, 15 industrialized nations that had fumigated with methyl bromide essentially no longer use it. Likewise, 87 developing countries, which don't have to phase out the chemical until 2015, have already abandoned it.

THE COST

In 2000, the US Department of Agriculture (USDA) published a report estimating that if growers had to switch from methyl bromide to the available alternatives, it could cost americans as much as $450 million each year (see chart below). Since that report, the US government has filed for exemption after exemption from the methyl bromide phase-out, under the loophole that people can continue to use the chemical if no "technically and economically feasible" alternative exists.

Growers need methyl bromide, simply because alternatives aren't as good, according to reggie Brown, executive vice president of the Florida Tomato Exchange and president of the Crop Protection Coalition, a lobbying group working to save methyl bromide. "It's not that we're wanting to continue to use [methyl bromide] because it's there and we don't want to change."

For example, Florida growers are plagued by nutsedge, a common weed that can compete with crops for nutrients and put holes in plastic that is used to regulate fertilizer and moisture in the soil. Methyl bromide controls nutsedge, but alternatives really don't do the job, Brown says. It costs up to $7,000 per acre before harvest to produce tomatoes, he estimates, so losing a crop to nutsedge or other weeds can have significant consequences, and not just to individual farmers. In Florida alone, tomatoes bring in close to $1 billion each year, and the tomato industry employs tens of thousands of workers, Brown says. To put that at risk is "not in the national interest."


However, Marten Barel, a consultant for several United Nations agencies, and a member of the Methyl Bromide Technical Options Committee (part of the UN Environment Program, or UNEP) argues that growers do not, in fact, need methyl bromide, because alternatives are available in most circumstances. "Many growers have already adopted alternatives and use them successfully in the US and other countries," says Barel. For instance, he notes that Holland was once the largest user of methyl bromide in europe, but the country phased it out a decade ago. The phase-out led to technical innovation and modernization in crop production, with many benefits for growers as a result, Barel says.

Moreover, since the 2000 USDA report predicting dire consequences from a methyl bromide phase-out, alternatives have been improved and are much more cost effective for growers, says Tom Batchelor, methyl bromide expert at the European Commission. "Now some combinations, such as alternative fumigants with additional weed control, give similar results in the US compared to methyl bromide." Indeed, a UNEP report released in May 2005 found that an increasing number of research studies show that modified and improved application methods are producing yields similar to methyl bromide in diverse situations.

However, someone involved in the Montreal Protocol, who spoke under condition of anonymity, notes that some US farmers are "incensed" at the prospect of losing "more tools from the toolbox," and are doing everything they can to keep methyl bromide. "a lot of energy and effort has gone into defending CUEs [critical use exemptions] rather than implementing alternatives." The USDA, for its part, has "taken a strong position to defend methyl bromide products rather than taking a neutral position on pest control methods, and has allocated money to projects that seem to show nothing is as good, rather than implementing viable alternatives."

PROGRESS?

Many users argue that they have cut back as much as they can on methyl bromide. In California, use of pesticides containing 1,3-dichloropropene, such as the methyl bromide alternative Telone, has increased markedly from 186 metric tons in 1995 to more than 3,100 metric tons in 2003. Brown says that Florida tomato growers have cut their use of methyl bromide by using different plastic films that slow emissions of methyl bromide. Farmers also employ a combination of methyl bromide and chloropicrin, and have increased the concentration of chloropicrin from approximately 2% to 34%.

UF's Dickson says he's received funds from the chemical industry, the vegetable industry, and the US government for years in his search for methyl bromide substitutes, and nothing works as well. The alternative 1,3-dichloropropene is also a carcinogen, so users must follow certain safety guidelines, such as not applying it too close to wells. many of the possible alternatives don't control one or more of the important soil-borne pests, such as weeds, nematodes, or fungi, as effectively as methyl bromide, says Dickson. Growers also have to wait many more days after using alternatives before planting, which can throw off the planting schedule, he adds. Indeed, Jack Norton, manager of the Ir-4 methyl bromide alternative program in North Brunswick, NJ, which works with the EPA, USDS, and other groups to develop alternatives, says that current CUEs are "absolutely" justified.

Exemptions were also part of the deal in the montreal Protocol, notes James Bair, vice president of the North American Millers' Association (NAMA) and vice chairperson of the crop protection coalition. (Approximately 5% of methyl bromide is used to fumigate structures such as enclosed mills that, like soil, vary from mill to mill owing to differences in size and construction materials.) Bair says that countries complaining about CUEs aren't holding up their end of the original bargain. There is no evidence to support the claim that the US government is simply following the methyl bromide lobbyists' wishes, he adds. Every year users reduce the amount of fumigant they're requesting when they apply for exemptions, the EPA reduces the allowable amount, and the UN cuts it back even further, Bair says.

Americans are not the only millers to ask for exemptions, he notes; milling industries in Europe, the United Kingdom, and Canada do so as well. "We have already made dramatic cuts in our use of methyl bromide," says Bair. But it's too early to do away with it altogether. "If there was something that was as effective, we would use it, but there is not."

If the alternatives don't work as well, users lose money, Bair notes. Flour mills generally run "24/7," he says, and shutting mills down to fumigate can be very expensive. Alternatives all take longer to work than methyl bromide, and that extra time costs millers thousands of dollars. For instance, if the average flour mill produces more than 450,000 kilograms of flour per day at 22 cents per kilogram, and if using an alternative fumigant would force the mill to shut down for 12 extra hours, that translates to a loss of almost $50,000 every time the miller fumigates, Bair notes. He argues that the problem with methyl bromide is not the ozone layer, but "politics," since the international community knows that banning the chemical will disproportionately hurt the United States, the biggest user.

Vanessa Bogenholm, a fulltime strawberry farmer in California, disagrees, and believes users have an obligation to cut back on methyl bromide. She says she stopped using methyl bromide in 1996, then spent one more year as a conventional farmer before going organic. In her last year as a conventional farmer, she used 1,3-dichloropropene (Telone). Bogenholm admits that the alternative was less effective at weed control, and it took an additional two months to get her field ready without methyl bromide, extra time that could make farmers lose a crop. But it was worth it, she says, and farmers who aren't willing to sacrifice some of their profits to protect the environment are being greedy. "Just because you're going to lose 20% of your profits" doesn't mean it's worth holding onto the chemical, she says. Because of this opinion, Bogenholm says she has been approached by other angry growers, even people she knows, who tell her to stop talking about farming without methyl bromide. "They don't want two or three people saying they can do without it."

Dave Mueller, owner of a commercial fumigation company in Westfield, Indiana, has been fumigating mills and other food-processing facilities without the use of methyl bromide since 1994. Since April 2004, his company has been using sulfuryl fluoride as an alternative fumigant. In July 2004, he described for Congress how he has successfully replaced 136,000 kg of methyl bromide with alternatives. He says that he has received a "tremendous" amount of resistance from lobbying groups and government officials in Washington, who seem to want to continue the use of methyl bromide in the United States. Mueller argues that he's worked hard to meet the US goal of phasing out methyl bromide in 2005, and he's losing business to fumigators who still use and promote the chemical. Methyl bromide users often have a competitive edge, he says, because alternatives can be more expensive and more labor intensive than methyl bromide. Millers also need to purchase new equipment and obtain advanced training to use these new alternatives. And besides this, people in the commodity groups are "conservative" and reluctant to change, according to Mueller.

Even companies larger than Mueller's are complaining that they're being penalized for complying with the methyl bromide phase-out timetable. On March 10, 2005, representatives from Dow Agrosciences argued to the US House Committee on Agriculture that they have spent more than $150 million developing methyl bromide alternatives containing 1,3-dichloropropene and sulfuryl fluoride. But since US users keep filing for exemptions, their efforts have been for nothing. In the statement, the company says that there is a "great deal of distortion and misinformation pertaining to alternatives," and the government's requests for exemptions "do not take into account the considerable progress that has been made" in finding alternatives.

However, NAMA's Bair argues that many of those who say there are alternatives have patents on such products, so they have something to gain if methyl bromide disappears. For instance, Dow sells a range of alternatives, and Mueller has patented an alternative regimen that combines heat, carbon dioxide, and phosphine to fumigate mills.

Still, part of methyl bromide users' reluctance to change stems from the fact that many are "addicted" to methyl bromide, says Kert Davies of Greenpeace. Methyl bromide works so well as a soil fumigant that the system of growing things has evolved around it, he says, and changing to alternatives means changing the machines, plastic, and entire system. Methyl bromide was the "silver bullet," he says, that allowed farmers to prosper unnaturally, and make "buckets" of money. "That greed is part of the resistance to change," notes Davies. "Tomatoes in February are a luxury, not a right."

Advertisement

Follow The Scientist

icon-facebook icon-linkedin icon-twitter icon-vimeo icon-youtube
Advertisement

Stay Connected with The Scientist

  • icon-facebook The Scientist Magazine
  • icon-facebook The Scientist Careers
  • icon-facebook Neuroscience Research Techniques
  • icon-facebook Genetic Research Techniques
  • icon-facebook Cell Culture Techniques
  • icon-facebook Microbiology and Immunology
  • icon-facebook Cancer Research and Technology
  • icon-facebook Stem Cell and Regenerative Science
Advertisement
Advertisement
Life Technologies