Food Quality & Protection Act was passed two years ago, but so far EPA has little to show for its efforts
By David J. Hanson

When it was passed unanimously in August 1996, the Food Quality & Protection Act (FQPA) was hailed by Congress as the most significant revision of the pesticide laws in more than 20 years. Its primary success was establishing a new standard for evaluating the health and safety of pesticides of "reasonable certainty of no harm."Unfortunately, in trying to implement this standard, the Environmental Protection Agency is hearing the same arguments about pesticides it has heard before.

Over the past several months, the agency and the numerous stakeholders that either support or oppose pesticide use have gotten bogged down over EPA's methods for review of pesticide residues on foods and whether these methods are fair and accurate. A special committee formed to debate these review methods just completed what was to be its final meeting, but the issues are far from resolved.

Consensus on the deeply dividing issues surrounding pesticide use was not the purpose of the committee, but members of the panel seem to agree that some convergence on a few issues occurred. These include increased public participation and ideas on how data might be posted on the Internet. Still, the only concrete result apparently will be the release of several science policy notices by EPA on how the agency will handle issues such as exposure measurements and dietary risk assessments.

The change in safety standards for pesticides in foods under FQPA was supposed to make it easier for EPA and the agricultural chemical industry to deal with pesticide residues on food. Previously, the applicable law for pesticide residues was the 1958 Delaney amendment,which flatly prohibited the addition to food of any compound that was found to cause cancer in humans or laboratory animals. The Delaney amendment was about to cause a number of useful pesticide products to be banned because they had been discovered to cause cancer in animals,and residues of those products were being found on processed foods.

Congress substituted the reasonable certainty of no harm standard because that would allow the continued use of pesticide products if EPA declared them safe. Congress did not stop there, however. It added that EPA would be able to reduce a product's residue limit 10-fold if there was not enough scientific evidence to show that that limit would be protective of infants and children. It also mandated that EPA had to consider a person's entire potential exposure to a pesticide, not just intake from food.

Deadlines were imposed on EPA for these reviews. All of the more than 9,700 specific residue tolerances were to be examined and updated within 10 years--the first third of these were to be completed byAugust 1999. EPA, realizing it had to work fast, took a look at what pesticides are used on foods and decided to examine the most likely problem products first. These happen to include some very common and long-used insecticides, the organophosphates and carbamates. Earlier this year, EPA hinted that many uses of these products might be too risky and that there could even be a wholesale banning of organophosphates as a group.

The resulting uproar from farmers, producers, and distributors of these chemicals gave the government pause, and Vice President Albert Gore called for establishment of the Tolerance Reassessment Advisory Committee (TRAC), an unwieldy body of 52 representatives from diverse stakeholders. Five TRAC meetings have been held, and, according to EPA officials, little has been resolved.

Scientific issues and the way the agency is handling them are at the root of the problem. "The scientific requirements of this law are very complicated," says Christopher Klose, vice president of communications for the Washington, D.C.-based American Crop Protection Association (ACPA), which represents pesticide makers. "The issues of aggregate assessments, cumulative risk, and common mechanisms of toxicity are all areas of science at the cutting edge." ACPA contends that EPA is not doing a very good job of meeting the scientific challenge.

In fact, ACPA and many other industry- and farm-related groups were so concerned that the TRAC process was not going anywhere that they developed their own "road map" for resolving the scientific issues, which they presented to the committee this summer. "This is our look at this law and our recommendations on how the various parts of the law should be dealt with," Klose says.

EPA has further aggravated pesticide makers and users by posting 16 preliminary risk assessments for organophosphates on the agency's Internet site. The purpose was to elicit public comment, but industry was upset. Bayer Corp.'s agriculture division manufactures several organophosphates, and Wayne C. Carlson, the division's vice president for regulatory affairs and field development, wrote EPA about the postings: "Putting preliminary, incomplete, or incorrect information on the Internet may be disparaging to our products or those of our customers."

ACPA reiterated these concerns and noted that the exclusion of information such as company correspondence would give only one side of the assessment. "Without full information, there is a possibility of misunderstanding the nature of those preliminary assessments and the risk of libelous disparagement," ACPA President Jay J. Vroom wrote to EPA.

Vroom tells C&EN that Internet postings raise other concerns as well. "The Internet posting is problematic because it so broadly disseminates the information, particularly to an audience outside the U.S., that there is greater potential for misinterpretations and uncalled-for market gyrations," Vroom says. He noted that in the short time since EPA posted the assessments, there has already been some misunderstanding on the part of foreign government regulatory agencies and some industrial customers that has caused some pesticide product marketing problems.

The incompleteness of the preliminary assessments is a problem being faced by Dow AgriSciences, Indianapolis. According to company spokesman Garry Hamlin, EPA is considering restrictions on the use of the organophosphate chlorpyrifos, which Dow AgriSciences manufactures, because EPA says it doesn't have enough safety studies. "Over the past five years, we have sent some 142 studies relative to the registration of chlorpyrifos. As many as 104 still remain to be reviewed by the agency. We're concerned EPA will pursue a risk assessment without making reference to the data already in the agency's hands," Hamlin says.

Industry has a general complaint that EPA is going to try to make decisions about pesticide use without enough information. "Our member companies are perfectly willing, and have offered, to generate reams of data and studies" on pesticide safety, ACPA's Klose says. He adds that it looks as if the agency is now being driven by the congressional deadline and doesn't care about more scientific data.

Environmental and consumer groups concerned about pesticide use think there are already enough data to warrant more controls on these products, especially the organophosphates and their uses on foods eaten by children. Charles M. Benbrook, an Idaho consultant to the Consumers Union, which is making a major issue of pesticide residues on food and children's health, says that the industry is not reading the FQPA safety standard strictly enough and is off track in its arguments.

"Industry rightly argues that there is very little evidence that pesticide residues in the food supply are a direct and immediate health threat to children," Benbrook says. "The reason FQPA will result in restrictions on organophosphates is that exposure to these chemicals at very low levels increases the risk across the population of very subtle, complex, difficult-to-document changes in neurological, reproductive, and immune development." According to Benbrook, these are the risks EPA needs to reduce by lowering residue tolerances, and not the acute toxicity risks being tested for by companies.

Stephen L. Johnson, deputy director of EPA's Office of Pesticide Programs, admits that having to spend several months working with TRAC has slowed down other work of the pesticide program. "We have put the reassessments on an accelerated pace, and anytime you commit additional resources to one area, you hurt your ability to move forward on other decisions." Still, he points out, the reassessments are a necessary activity. He says that in the coming month, EPA will be releasing preliminary assessments on the remaining 24 organophosphate pesticides, most likely finishing in December.

EPA will issue nine science policy papers in the Federal Register over the next several months to clarify its thinking on pesticide tolerance reassessments. Johnson says these will include papers on aggregate risk assessment, cumulative risk assessment, and how the agency will conduct dietary exposure measurements. "Part of these nine policy issues will be fundamentals such as data reliability and the use of defaults and assumptions," Johnson says.

Johnson says that despite the slowdown in the process, the agency still expects to meet its statutory deadline of having nearly 3,000 residue tolerances updated by August of next year. He says this is partly because EPA is working on other residue assessments, not just the organophosphates. "We believe we can numerically meet the mandated deadline," he says.

In a June 30 New York Times article, a science adviser to the Atlantic Foundation writes in a freelance article that the shortest list of problems threatening our children should include: 1) obesity, 2) poor nutrition, and 3) asthma.

Yet the EPA's Children's Health Protection Advisory Committee included only asthma on its top-five list. Instead, the EPA panel has adopted essentially the agenda that environmental groups wanted them to take, emphasizing the dangers of pesticides as the greater enemy. The article goes on to say that this is what might be expected from an agency with the word "environmental" in its name, but the problems facing American children are not so easily cataloged. What seems like solutions from a narrow environmental viewpoint could be distractions from other, more important issues and in fact could hurt children's health. Data shows that asthma is growing at a terrible rate. The U.S. Centers for Disease Control and Prevention estimates that 15 million Americans now suffer from it, with the number of doctor's office visits resulting from the disease doubling between 1975 and 1995. African Americans are hit hardest of all. Their hospitalization rate for asthma was more than three times that of whites, and their death rate from the disease is more than seven times higher.

The EPA blames air pollution for the increase in incidence of asthma because bad air quality from pollution or cigarette smoke, for example, can aggravate the symptoms of asthmatics. Yet EPA's own data shows that air pollution levels have steadily declined as the disease has skyrocketed. A study published recently in The Lancet (a British medical journal) looked at the hospital admission records for 460,000 children in 56 countries and found that asthma rates were highest in countries with the least air pollution. A study on the causes of asthma published in The New England Journal of Medicine says that blaming air pollution "is political, not medical," and that research has found that the disease's primary cause in American inner cities, where asthma rates are the highest, is actually the inhalation of dried cockroach excrement. Researchers were cited as saying we should not concentrate so much on air pollution and instead declare war on roaches.

Concurrently, however, the EPA is considering limiting or banning many organophosphates and carbamates, two types of pesticides that are potent cockroach killers. The authors cited the fact that although 30 years' use has shown these chemicals pose very little danger to humans when used properly, the EPA committee on children continues to voice concern about the use of both of these classes of pesticides, a campaign that they say can only harm children and help roaches. They also believe that making these insecticides a target will harm children's health in another way: because these pesticides are vital in controlling crop-eating insects, restrictions on their use would mean that fruit and vegetable prices would probably rise. More than 200 studies associate low consumption of fruits and vegetables with higher risk of cancer. A study published in 1995 in the Proceedings of the National Academy of Sciences reported that the one-quarter of the U.S. population with the lowest dietary intake of fruits and vegetables, disproportionately inner-city minorities, suffers roughly twice the cancer rate as the one-quarter of the population that eats the most produce.

The University of California-Berkeley's Dr. Bruce Ames, a biochemist and director of environmental health science, has been quoted as saying that "It just does not make any sense to spend $146 billion on EPA regulations, a few billion on cancer treatment research, and practically nothing to get people to eat good diets." Further, our youngsters' atrocious eating habits have led to an explosion in obesity, making American children among the fattest on earth. From 1963 to 1970, Government data show only 5 percent of children ages 6 to 11 were obese. Since then, that percentage has almost tripled. For children ages 12 to 17, it has more than doubled. Again, minority groups suffer the most.

Moreover, a recent Harvard study reported that one apparent cause of asthma is, yes, obesity. In the past, doctors presumed that people who have asthma become obese because the disease makes it difficult to exercise. But this study found that the heavier adults are, the more likely they are to develop asthma. Chemically Speaking August 1998

"Safety" of 2 OP Residues in Food

According to the World Health Organization (WHO), food residues of two commonly used organophosphate insecticides are unlikely to cause adverse health effects. Levels of diazinon detected in edible crops and animal feeds "have been far below the acceptable daily intake" thresholds, declares WHO summaries. Additionally, the Organization says that the general population's food residue exposure to oxydemeton-methyl (Metasystox-R) likewise does not put humans at risk.

The WHO stated that both dietary and occupational exposure to these two organophosphates are unlikely to produce adverse health effects if recommended safety precautions from the chemicals' manufacturer are followed. There is, however, still the need for precautions to minimize exposure of non-target organisms, but these chemicals do not persist in the environment and are "not accumulated by organisms." WHO's summaries in part draw their conclusions from reports of accidental, suicidal, and occupational poisonings.

The book number for WHO's Environmental Health Criteria series summary for diazinon is #198, and for oxydemeton-methyl is #193. Additional information on these summaries and other similar books is available on WHO's Internet site at http://www.who.ch/pll/dsa/cat95/zhow.htm

Conversely, a preliminary analysis by the EPA shows that 20 organophosphate insecticides expected to be found in some people's diets pose risks that exceed those allowed by the Food Quality Protection Act. The Agency did not identify which 20 OPs were analyzed. These assessments are, according to EPA, "truly works in progress" and represent varying levels of refinement in their risk assessments to date for OPs. EPA wants it known that a "major message for all" is that there is opportunity to refine assessments to reflect actual or potential risks better, with information from pesticide users, registrants and public interest groups. Chemical Regulation Reporter; June 26 and July 10, 1998; Chemically Speaking August 1998

ACPA SAYS MARKET BASKET SURVEY WILL SHOW OP EXPOSURE LESS THAN PREDICTED

The levels of 20 organophosphates (Ops) found as residues in people's diets exceed EPA's reference or "safe dose," according to preliminary data the agency presented at the June 22-23 meeting of the newly formed Tolerance Reassessment Advisory Committee (TRAC).

EPA's estimates dealt with dietary exposure to single Ops only. The figures did not discuss exposure through lawn, home and other pathways, as the Food Quality Protection Act (FQPA) requires. Nor did the analysis look at the cumulative risk posed by the pesticides that affect the body in the same way, which EPA argues Ops do.

The snapshot is worrisome, said Dr. David Wallinga, a physician with the Natural Resources Defense Council. He did not, however, call for EPA to cancel any uses, noting the preliminary status of the data.

But, EPA should put all the information on the table so the public can consider the question of whether some uses should be canceled before the agency officially reviews the Ops as scheduled next year, Wallinga said.

" I don't understand why [the data] are preliminary," said Jay Feldman of the National Coalition Against the Misuse of Pesticides. The agency was only discussing dietary data. It has enough information on dietary exposures that the data should not be considered preliminary, he said.

The data were very preliminary, said Ray McAllister, director for regulatory affairs with the American Crop Protection Association, the pesticide manufacturers trade organization.

Risk assessments are conducted in a phased or "tiered" approach in which the agency makes assumptions designed to overestimate risk and refines the assumptions with better data.

There was no way to know what stage of the risk assessment each OP was in, McAllister said. If the estimates were based on the first, or screening stage, the figures could have overestimated exposure well over 1000 times.

EPA did not reveal the names of the chemicals, identifying them instead by numbers. Hence pesticide manufactures could not respond to EPA's data during the meeting, he said. But companies can guess which products are theirs, so they are now reviewing EPA's analysis.

" We were concerned about how [the data were] presented. It looks like there is a vast over-exposure, when we don't believe that is the case," McAllister told EHL after the meeting.

By the end of the year ACPA plans to begin an extensive market basket survey to determine OP residues. The organization also may carry out a drinking water survey.

McAllister predicts these surveys will show that actual exposure is "dramatically lower" than EPA's estimates. The information, however, may take a year or more to analyze.

EPA is scheduled to begin its review of OP tolerances next year.

McAllister said EPA might have to postpone the review so that it can use the market basket information. The FQPA requires the agency to use "reliable" data, he noted.

EPA staff, however, note the law requires the agency to use "available" data.

Feldman and McAllister agreed on one issue: lack of time. Both were concerned that so much time is being spent at the TRAC meeting making members who are less familiar with the pesticide-registration process understand how it works that valuable time to give EPA feedback is being lost.

Also, EPA is releasing so much information in such a short time frame that it is almost impossible to read and give cogent response, McAllister said.

Nevertheless, McAllister was pleased that EPA has announced it will publish and request comment on some key policy decisions that affect its risk calculations.

The June meeting was the second of four meetings of the 45-member TRAC panel formed after Vice President Al Gore ordered EPA to take agricultural interests into account when implementing the FQPA.

By September, EPA hopes to include TRAC's recommendations in guidance on the use of Monte Carlo analysis in pesticide tolerance decisions and of a draft model for assessing residential exposure.

By October, the agency seeks to publish draft guidelines for the so-called "children's" safety factor, the law's requirement that, to protect children, EPA use an additional 10- fold margin of safety in setting legal residue limits unless the agency is certain children will not face additional risk from the pesticide. Also scheduled for October publication is draft guidance on determining pesticide exposures through drinking water.

By November, EPA expects to publish a proposed method of what to do in tolerance assessment when no residues are detected in food, although the residues may be there in small enough amounts that they cannot be detected with current testing procedures. In that month, also, draft guidelines would describe a method for aggregating exposures from all non-occupational sources.

In January of 1999, the agency would publish draft guidance on how to conduct a cumulative risk assessment for all exposures to pesticides with similar modes of action, such as organophosphates and other pesticides that act upon central nervous systems. All guidance would be subjected to public comment, with 30 or 60-day comment deadlines. (Environmental Health Letter, July 1998); Pesticide Reports August 1998

REGISTRATION SOUGHT FOR PHOTOACTIVE PESTICIDE

PhotoDye International, Inc. last week submitted to the Environmental Protection Agency its application to register SureDye, a photoactive pesticide.

The Baltimore-based company is seeking an expedited review for SureDye as a reduced risk pesticide, the active ingredient of which is Phloxene B, or Red Dye 28.

The dye already is registered with the Food and Drug Administration for use in drugs and cosmetics. As a pesticide it would be used to kill Mediterranean fruit flies which ingest the bait with which it is mixed. In sunlight, the Phloxene B acts as a powerful oxidant within the flies.

PhotoDye founder Jim Heitz also is developing a mixture to use against the corn rootworm, company spokesman Lowell Kasden told PTCN, and it might one day be used against other pests as well. If so, the pesticide might serve as a substitute for the organophosphate pesticides which are currently applied against those insects. According to the latest, albeit unreviewed, test results from Morocco, added Kasden, SureDye shows an efficacy against medflies equivalent to that of malathion.

According to EPA, the registration period for an active ingredient granted reduced risk status is 14 months. Conventional registrations average 38 months.

Kasden said there have been no inquiries from within the U.S. to use SureDye because it has not been registered, nor has there ever been any attempt to use it under a Federal Insecticide, Fungicide and Rodenticide Act Section 18 exemption. (Kasden may be reached at 410-435-4886). ( Pesticide & Toxic Chemical News, May 21,1998); Pesticide Reports July 1998

Botanical Extracts Reduce Populations of Soil Pathogens

Principal Investigators: James C. Locke and John H. Bowers, Research Plant Pathologists, Floral and Nursery Plants Research Unit, U.S. National Arboretum, USDAARS, Beltsville, MD 20705

There are a number of soilborne fungal pathogens that are of concern in the production of ornamental crops. To combat these pathogens, methyl bromide has been used to fumigate soil prior to planting many of these crops. One such example is Fusarium wilt of chrysanthemum, a widespread and destructive disease of this major horticultural crop. Symptoms of this disease may not become evident until near the time of flower production, although infection takes place early in the crop cycle.

The overall goal of this research project is to develop and evaluate new or existing, biologically based alternative control methods that can be integrated into cropping systems which currently use methyl bromide. Environmentally safe alternatives such as natural plant products, biological control agents, and cultural methods are being investigated. Major soilborne pathogens, Fusarium, Rhizoctonia, Verticillium, and Phytophthora are being used in bioassays designed to determine impact on soil populations and disease reduction in selected crops. This report focuses on the effect of several formulated plant extracts in reducing soil populations of Fusarium oxysporum f. sp. chrysanthemi (F.o.c.).

Artificially infested soil samples were treated with several rates of the botanical materials, incubated under standardized conditions, and assayed periodically to determine survival of the pathogen. The materials evaluated included the following formulations: 70 percent clove oil, 90 percent neem oil, pepper extract plus oil of mustard (4.94 percent capsaicin, 4.43 percent allyl isothiocyanate), cassia tree extract (Abion M), and the standard soil-drench fungicide Banrot 40W. Fusarium population determinations were made at 0, 1, 3, 7, 14, and 21 days after soil treatment. The natural product formulations were applied as 1, 5, and 10 percent aqueous emulsions at 5 ml per 150 cubic centimeters of soil.

Neither Banrot nor 1 percent applications of any of the botanical extracts reduced the population of F.o.c. compared to the untreated control. However, the 5 and 10 percent applications of the botanical extracts resulted in significant differences in the surviving F.o.c. populations at each assay date. Treatment with the neem oil material actually resulted in increased F.o.c. populations.

Soil populations of F.o.c. were lowest after 3 to 7 days of incubation with the pepper extract. In addition, populations of other soil microbes were also reduced to the greatest degree when treated with the pepper extract. The F.o.c. populations did rebound over time, showing a steady increase beginning 7 days after treatment. This increase could be the result of either breakdown of the pepper extract in soil or the lack of microbial competition which allows any surviving F.o.c. propagules to rapidly recolonize the treated soil. This may also occur with the clove oil and cassia extract but to a lesser extent. Further research will address these population dynamics questions.

The ability of these natural products to reduce soil populations of these pathogens coupled with their environmentally friendly composition makes these materials attractive candidates for use in biologically based management strategies. In the highly intense management of high value ornamental crops, these materials may be part of the answer to the quest for an alternative to methyl bromide fumigation. However, to fully develop an alternative cultural practice, these materials may need to be integrated with other practices such as the use of beneficial or biocontrol agents.

Additional research needs to be completed to scale-up these findings to actual production systems. Application rates and methods, pre-plant incubation periods, tolerance of various crop plants, and impact on soil microbial systems are being addressed. Whether this technology could be adapted for use with agronomic crops remains to be determined. ARS Methyl Bromide Alternatives Newsletter V 4 No 14 Jan. 1998 (http://www.ars.usda/is/np/mba)

Grower Reports on Field Tests for Preplant Methyl Bromide Alternatives

For a year, Dave Murray, a strawberry grower in Oxnard, California, has participated in the field validation project initiated by the Agricultural Research Service in 1995. The mission of the projectwhich is also sponsored by the California Strawberry Commission and the University of Californiais to validate in the field, on as large a scale as possible, preplant alternatives to methyl bromide fumigation. (See Methyl Bromide Alternatives, April 1996, pp. 12, "Update on Field Tests for Preplant Methyl Bromide Alternatives.")

Murray, who grows Camerosa strawberries, fumigates with methyl bromide to increase plant vigor and control weeds. "Without methyl bromide, my crop would be subjected to increased risk from soilborne and root diseases." "I used four treatments for my experiments: methyl bromide, Basamid, Telone II with chloropicrin, and chloropicrin by itself," Murray says. "I must say that Basamid, by far, outperformed the other alternatives."

Murray used half-acre plots for each experiment. In the control plot, he fumigated with methyl bromide and chloropicrin (57:43) at 325 pounds per acre. Yield was 7,920 pounds per acre.

He applied Basamid to two replicated plots: one with 350 pounds per acre; the other, 450. "At the beginning of March, yields from both of these plots were significantly higher than those from the methyl bromide plots," he reports. "I'm still collecting data, but yields through March 6 are the most important since that is when the market price is highest."

Plots fumigated with 400 pounds per acre of Telone II/chloropicrin (65:35) yielded about the same as the methyl bromide plots. "But I started to see a change after March. Production in this plot started to drop off somewhat," Murray says.

The plot treated with only chloropicrin (at 200 pounds per acre) produced slightly higher yields than the control.

According to Murray, controlling weeds is just as important as increasing or maintaining yield. "Methyl bromide was the only treatment that completely controlled weeds. But Basamid did a fairly good job. It controlled weeds at an acceptable level, whereas Telone/chloropicrin didn't do well at all."

"As a production manager, I need to know about every viable alternative to methyl bromide. We are going to lose methyl bromide after January 1, 2001. I appreciate being included in this study because, to stay in business, growers must have alternatives and I want to know as much as I can about all the possible options."

At this time, Murray says, Basamid seems to be the choice alternative chemical. Although Basamid is not yet registered for use on food crops, the chemical company BASF is actively seeking registration from the U.S. Environmental Protection Agency.

"One problem I have with Basamid is that you really need ideal conditions for it to work effectively," Murray notes. "Ideally, soil temperature needs to be 70 degrees or greater. In granular form, Basamid must react with soil moisture to degrade to a gas. We fumigate in September and plant in October. Is this enough time to convert Basamid from granular to gas form and have the gas dissipate?"

He says that in tests this year, the soil was free of gas in 2 to 3 weeks after treatment.

To test soil readiness in this study, Murray planted a pepper plant. The plant survived, which meant that the soil was free of gas. Had the plant died or growth been stunted, more time would have been needed to clear the soil of the gas.

Basamid is currently registered by EPA for nonfood uses such as in horticultural nurseries, forest tree nurseries, turf grass production, and golf course green construction and renovation. It can also be used on nut and nonbearing fruit crops. EPA granted an experimental use permit for growers in the validation program to use the chemical for field tests.

"The bottom line is: Strawberry growers need an alternative. This project has shown that Basamid will work if conditions are favorable," Murray says.

According to Ken Vick, USDA methyl bromide coordinator, some alternatives may or may not work equally well under fluctuating conditions, and their limitations must be explored.

"Methyl bromide is a compound that takes care of variabilities in temperature, rainfall, soil moisture content, and pest pressure. And after decades of use, it continues to be a robust fumigant that works over a wide range of conditions," he says. "We've been testing methyl bromide alternatives at different locations over a period of years to determine the extent to which they can handle variabilities of these factors. We intend to continue our research on Basamid as well as on other alternatives to compare their effectiveness with methyl bromide under fluctuating conditions." ARS Methyl Bromide Alternatives Newsletter V 4 No 3 July 1998 (http://www.ars.usda/is/np/mba)

Reviving Propargyl Bromide, A Chemical From the Past

As the January 1, 2001, deadline for the ban on methyl bromide looms nearer, scientists from around the world intensify their search for viable alternatives.

Scott R. Yates is reviving interest in propargyl bromide, a chemical used with chloropicrin and methyl bromide in Trizone, a fumigant developed in the l960s. Yates is a soil scientist with the Agricultural Research Service's U.S. Salinity Laboratory in Riverside, California. He reported this research at the Annual International Research Conference on Methyl Bromide Alternatives and Emissions Reductions held in San Diego, November 35, 1997.

"The increasing popularity of methyl bromide back in the '60s is one reason that propargyl bromide was never commercialized," Yates reported. "Since the compound is not currently registered by the Environmental Protection Agency as a pesticide, its environmental behavior is essentially unknown."

In tests, Yates and colleagues at Riverside found that under typical agricultural conditions, this chemical appears to pose no serious environmental risk. "It degrades quickly in the soil. This would help limit the amount of the chemical that reaches groundwater or escapes into the atmosphere," he said.

Since virtually no information exists on propargyl bromide, Yates concentrated research efforts on basic parameters such as solubility, saturated vapor density, and the ease with which the chemical moves through the soil and escapes into the atmosphere. This knowledge is critical before a decision can be made on whether the chemical should be used as a soil fumigant, Yates said. The data are also needed to design methods that minimize application rates and optimize control of target organisms.

Yates compared the solubility of propargyl bromide (3BP) with that of methyl bromide and 1,3dichloropropene (1,3D), a potential methyl bromide alternative. Solubility determines how quickly a chemical is transported with water moving through porous substances.

"At low temperatures, the solubility of propargyl bromide increases rapidly as temperatures rise, and then levels off. We found that this chemical dissolves into water at a rate comparable to methyl bromide," Yates said. "And under high leaching conditions, more propargyl will move with water than 1,3D, since 1,3D is less soluble."

According to Yates, since it is important that a chemical move rapidly through the soil, all agricultural fumigants generally have high saturated vapor density. The saturated vapor density gives an indication of the tendency of a chemical to prefer the vapor phase.

In soil tests, 3BP degraded at a rate similar to 1,3D, but much faster than methyl bromide. In theory, Yates said, that part of a chemical applied to the soil which doesn't degrade will eventually enter groundwater or the atmosphere. Since 3BP degrades rapidly in soil, it will have lower volatilization and is less likely to leach into groundwater than methyl bromide. "Because of its easy movement through and low retention rate in the soil, 3BP should provide a fairly uniform fumigation," said Yates. "Unless the soil is covered with a barrier like an impermeable plastic film, most agricultural fumigants will have a high rate of emission into the air. In fact, very high emission rates are reported for both methyl bromide and 1,3D in field and lab tests.

"On one hand, high emission rates would reduce phytotoxicity and possible groundwater contamination. But on the other hand, air emissions could produce undesirable health effects on people living or working near treated fields. Since propargyl bromide is highly degradable, little would reach the atmosphere or groundwater, compared to methyl bromide," he reported.

Propargyl bromide has characteristics which suggest that it would be environmentally safe and, therefore, warrants consideration as a methyl bromide alternative, Yates said. "However, further research is needed to determine its effectiveness in controlling pests and to further study its fate and transport behavior under typical farming conditions."

ARS Methyl Bromide Alternatives Newsletter V 4 No 14 Jan. 1998 (http://www.ars.usda/is/np/mba)

AT LAST, ZOOLOGISTS MAY KNOW WHAT IS KILLING THE WORLD'S AMPHIBIANS; A GREAT LEAP FORWARD

Frogs and toads throughout the world are being killed by a fungus that is new to science. The fungus, which coats their undersides and legs, is thought to be suffocating the animals, which breathe through their skins. It could be a major factor underlying the decline in amphibian populations reported worldwide. The fungus has been found independently by teams in the US and Australia. It belongs to a new genus of chytrid, a group thought to be related to the earliest fungi. Although other chytrids parasitize a range of organisms, from microscopic algae to insect, they have never before been found to cause a disease in vertebrates. The fungus, which has yet to be given a scientific name, is known to have struck down 10 species of frogs and toads from 10 locations in Australia, seven species from two locations in Panama, a toad from southern California, and six species of frogs in four American zoos and aquariums. " There's little doubt that this is a worldwide phenomenon," says Allan Pessier, a veterinary Pathologist at the National Zoological Park in Washington DC. The scientists don't yet know if the fungus is the primary cause of death, or is killing animals weakened by other factors, such as ozone layer or agricultural chemicals. "Many factors could be at work, but the fungus is probably right up there," says Pessier. Nobody knows where the fungus came from, or how it is spread (see below). It was first noticed by Don Nichols, a colleague of Pessier's at the zoo in Washington DC, in arroyo toads, Bufo microscaphus californicus, from a captive colony in California. At first Nichols didn't recognize it as a fungus. Because infected skin contained a proliferation of round cells, rather than fungal filaments, Nichols thought it was a protozoan. Earl Green of the Maryland Animal Health Laboratory in College Park made the same mistake when he examined specimens collected in 1996 and 1997 from western Panama by Karen Lips of St. Lawrence University in Canton, New York. By 1996, Nichols and Pessier had begun to doubt the protozoan diagnosis. Then an outbreak of the infection began to ravage the National Zoological Park's population of blue poison-dart frogs, Dentrobates azureus, which come from Surinam. Nichols and Pessier teamed up with Joyce Longcore, a chytrid taxonomist at the University of Maine in Orono, who described her findings to the Mycological Society of America in Puerto Rico last week. (New Scientist press summary, June 24, 1998)

Pesticide Reports August 1998

WATER QUALITY LAWS TO COMPLICATE FQPA PROCESS, MULKEY WARNS

Amendments to the Safe Drinking Water Act and a new initiative to beef up the Clean Water Act are sure to complicate EPA efforts to implement the Food Quality Protection Act, Marcia Mulkey, director of the Office of Pesticide Programs, said at this week's meeting of the State FIFRA Issues Research and Evaluation Group (SFIREG).

The June 28-29 meeting in Washington, D.C., was held to address the role that states will play in regulating pesticides and antimicrobials. Mulkey stressed that this role will be vital to OPP, but warned that 1996 revisions to the drinking water law, as well as President Bill Clinton's pledge to speed up efforts aimed at making all the nation's water bodies "fishable and swimmable," will be something of a "curve ball" for state pesticide officials.

" I suspect that the FQPA is on your minds almost as much as mine," Mulkey said. "The Safe Drinking Water Act has not quite hit us in terms of how it affects us, but it will, and fairly soon. All of a sudden we will have to develop much more monitoring data on pesticides in water."

Mulkey argued that the new food law, along with the water initiatives, have put such stable regulatory programs as that of OPP into a situation reminiscent of the early 1970's, when "a lot of people with an awful lot at stake" were trying, for the first time, to establish a regulatory framework for environmental regulation.

To help the states address the political and logistical nightmare which might result from regulating pesticides from widely divergent standpoints, Mulkey said that, as a first step, EPA will be resurrecting its "week-in-residence" program.

Under this presently dormant program, state regulators will spend a week at EPA headquarters to, as Mulkey put it, "hang out with us" while their federal counterparts will be following suit at state offices.

Marion Fuller, who heads Florida's pesticide bureau thought the idea was "tremendous" because state regulators all are experiencing "some excitement but mostly fear over the changes brought about the FQPA."

She also said that "the week-in-residence" shouldn't be limited to people from the states and headquarters. You need to involve people in the regions, too. It would be a `win-win' deal for all of us."

In fact, the efficacy of EPA's regional regulation emerged as a cause for concern during the meeting. Twenty years ago, as pesticide programs were being established, the states were trying to follow the lead of EPA. Over that time, the level of competency at the states has increased but the level of regional enforcement has decreased.

A lapse in "competency...often happens in any well-established program," said Rick Colbert, from EPA's office of enforcement and compliance assurance. "People eventually leave and they take their experience with them. So, you're hiring less experienced people to replace them."

In addition, Colbert said, alluding to long-standing regulatory programs, "the old stuff isn't sexy any more." But such "old stuff" as pesticide regulation is being subjected to a "sea change," and not just because of the water laws. "In the past, EPA was focused mostly on industry, but now we're starting to focus on agriculture," Colbert said. "The Clean Water Action plan focuses on agriculture. The Office of Water is talking to USDA. Things are changing."

Colbert warned, however, that there will be a mess if state and federal water regulators try to "duplicate the wheel by trying to do what OPP does. You make mistakes when you do that. There's no use stepping on toes," Colbert added, alluding to the politics of bureaucracy, "and there's no sense in trying to recreate relationships which already exist."

Moreover, such duplications would be exacerbated, said Mulkey, alluding to the tolerance reassessment initiative under way at OPP, by ill- conceived initiatives developed in response to FQPA mandates. "I know that some truly pin-headed things get designed in Washington, and that's because, sometimes, there's a lack of understanding of how these things are manifested in the real world." (Pesticide & Toxic Chemical News, Vol. 26, No. 31, July 2, 1998); Pesticide Reports August 1998

Pesticide use today is killing us? One hundred years ago, the average life expectancy in this country was less than 50 years. Today, a baby born in the U.S. can expect to live about 76 years, even longer if she is a baby girl. Because life-span figures include such misfortunes as car accidents and violent crime, many people live much longer than the average. In fact, the fastest growing segment of our population today is people over 85. There are certain significant contributing factors we have to thank for our longer lives: improved sanitation, antibiotics, and high-tech medicine. How do you stay active and healthy in your 50s, 60s and 70s? Adopt a healthy lifestyle in your 20s, 30s and 40s. Experts recommend eating a Mediterranean diet, one high in vegetables, fish, olive oil and pasta. Exercise at least three hours a week, not just to burn calories, but to work the heart, keep the body's hinges flexible and build up strength. Do not smoke or consume excessive amounts of alcohol. Avoid head trauma by using bicycle helmets, seatbelts and air bags. AP; July 1, 1998; Chemically Speaking August 1998

Think about this for a minute: the world's production of grain will have to almost double by the year 2020. Ontario Farmer Daily; Jan. 29, 1998 via Agnet ;Chemically Speaking August 1998

The lesser cornstalk borer's damage to peanuts has a 94 percent correlation with aflatoxin. Aflatoxin is one of the most potent carcinogens ever discovered. What will happen to peanuts if we cannot control this borer without organophosphates? Georgia Pest Management Newsletter; May/June 1998

Chemically Speaking August 1998

Termites that are plaguing southern Louisiana are expected to leave at least $500,000 worth of damage this year. The exotic Formosan termite has spread beyond New Orleans into Baton Rouge. LSU scientists say at least 75 homes in the capital city are infested with the pest. Chemically Speaking August 1998

EPA's current "best effort" at evaluating aggregate and cumulative exposures from 40 organophosphate pesticides indicates that even by themselves, several of these chemicals overflow the available "risk cup" by factors of ten to 50. When these exposures are cumulated for the entire class of chemicals, the Agency's current working data produce an exposure estimate that appears to be more than 100 times higher than that allowed under the Food Quality Protection Act's health-based standard for pesticide regulation. Food Regulation Weekly; July 27, 1998; Chemically Speaking August 1998

Members of the Center for Disease Control's mycotic diseases division has recommended that EPA should withdraw its approval of all tetracycline and streptomycin products used as pesticides. They believe that since there is resistance to these products in the field, this resistance may have transferable effects on humans. Pesticide and Toxic Chemical News; June 18. Chemically Speaking August 1998

1998 Darwin Award Runner Up

An insurance company asked for more information regarding a work-related accident claim. This was the response: "I put 'poor planning' as the cause of my accident. I am an amateur radio operator and was working on the top section of my new 80 foot tower. When I had completed my work, I discovered that I had, over the course of several trips up the tower, brought up about 300 pounds of tools and spare hardware. Rather than carry the materials down by hand, I decided to lower the items using a pulley.

Securing the rope at ground level, I went to the top of the tower and loaded the tools into a small barrel.

Then I went back to the ground and untied the rope, holding it tightly to ensure a slow descent of the 300 pounds of tools. You will note in block number 11 of the accident report that I weigh 155 pounds.

Due to my surprise of being jerked off the ground so suddenly, I lost my presence of mind and forgot to let go of the rope. I proceeded at a rather rapid rate of speed up the side of the tower. In the vicinity of the 40 foot level, I met the barrel coming down. This explains my fractured skull and broken collarbone.

Slowed only slightly, I continued my rapid ascent, not stopping until the fingers of my right hand were two knuckles deep into the pulley. I regained my presence of mind and was able to hold onto the rope in spite of my pain. At the same time, however, the barrel of tools hit the ground and the bottom fell out of the barrel. Devoid of the weight of the tools, the barrel now weighed approximately 20 pounds. I refer you again to my weight in block number 11. As you might imagine, I began a rapid descent down the side of the tower. In the vicinity of the 40 foot level, I met the barrel coming up. This accounts for the two fractured ankles, and the lacerations of my legs and lower body. The encounter with the barrel slowed me enough to lessen my injuries when I fell onto the pile of tools so only three vertebrae were cracked. I am sorry to report, however, that as I lay on the tools, in pain, unable to stand and watching the empty barrel 80 feet above me, I again lost my presence of mind and let go of the rope..."