North Dakota State University
NDSU Extension Service
Volume 15, No. 4 -- October 1997
Pesticide
Perceptions
Tulane University Lab to Retract Study That
Reported Dramatic Synergism in Weakly Estrogenic Chemicals
Pesticides: A Point of View
In This Issue
Coordinator's Comments
Law
Insect Control
Disease Control
Weed Control
Equipment
Safety
Training
In the July 25 issue of Science, John McLachlan will retract his laboratory's well publicized study that found mixtures of weak estrogens could be significantly more powerful when combined than when tested individually.
McLachlan's retraction will lay to rest an international debate that ensued after Tulane published a study that found mixtures of weak estrogens including two pesticides, dieldren and toxaphene, could be up to 1600 times more powerful in combination. That study appeared in the June 7, 1996, issue of Science. McLachlan directs the Tulane/Xavier Center for Bioenvironmental Research in New Orleans.
Tulane plans to retract its study because neither the university nor other laboratories can reproduce the results, McLachlan told Pesticide & Toxic Chemical News in a July 21 interview.
Tulane's research captured attention worldwide. The funding offered a possible explanation of how low levels of chemicals might be causing increased breast and testicular cancers along with other maladies people have reported and which some scientists say may be caused by endocrine disruptors chemicals that mimic, block or alter hormonal activity.
If the university's findings had been replicated, EPA could have dramatically reduced tolerances, legal pesticide residues. At several public forums on endocrine disruptors, Penelope Fenner-Crisp, then deputy director of EPA's Office of Pesticide Programs, said that if other laboratories reproduced Tulane's results, EPA likely would have to change the way it assessed risks of endocrine disruptors. EPA currently assumes chemicals act in an additive manner, meaning a mixture's toxicity can be predicted by summing the potency of the individual chemicals that make up the combination. Occupational exposure limits and other federal standards also could have been affected if Tulane's results had been repeated.
The Chemical Industry Institute of Toxicology, Duke University Medical School, the national Institute of Environmental Health Sciences and Texas A&M University jointly tried and were unable to replicate Tulane's study. The four laboratories' research was published as "technical comment" in the Jan. 17 issue of Science; the full study also was published in the April issue of Endocrinology.
Zeneca Central Toxicology Laboratory in Cheshire, England, also was unable to replicate the results. A letter on the study was published in the Feb. 6 issue of Nature.
McLachlan's laboratory has been exploring three hypotheses that might explain the synergistic results in his laboratory's original study. Using a yeast assay, Tulane tried to see if the number of receptors affected the outcome. The synergistic effect, McLachlan speculated, might come into play when chemicals are fighting for a few receptors.
The laboratory also tried to determine whether the structures of the estrogen receptors caused the synergism. Estrogen receptors may be single (monomer) or paired (dimer).
Finally, Tulane tried to determine whether the protein, called a transporter mechanism, that brings chemicals into cells might explain the disparate results. The research team hypothesized that some chemicals might be transported more efficiently or that the protein might work more efficiently in some yeast strains, McLachlan told PTCN.
But none of these theories explained why the synergistic results could not be replicated, McLachlan said, adding, "I don't know why."
McLachlan said he felt it important to publish a formal retraction because "a lot of people have given this study a lot of accord in the public policy debate."
Previously, a toxicologist who requested anonymity told PTCN that political appointees at EPA jumped on Tulane's study to push a "we need regulations" agenda (See PTCN June 4, Page 5).
John Gibbons, director of the White House Office of Science and Technology Policy, referred to McLachaln's retraction at the July 21 session of Estrogens in the Environment IV, a conference hosted by NIEHS. There are many uncertainties surrounding endocrine disruptors, Gibbons said. As research continues, "some observations will be found true and others found not valid." Tulane has been unable to replicate its results, Gibbons continued, and "the scientific process moves forward."
McLachlan is best known for his research on diethylstilbestrol, a drug used in the 1950s that caused vaginal cancer in the daughters and reproductive abnormalities in the sons of women who had taken the drug during pregnancy. The discovery that DES could harm offspring who were exposed in the womb foreshadowed current interest in endocrine disruptors.
Copies of the poster session abstracts from NIEHS' conference are available from PTCN's Documents Express service (PTCN3905, 68 pages, $21.)
(Source: P&TCN Vol. 25 No. 39)
I believe that for North Dakota, United States, and world agriculture, pesticides are absolutely necessary; now and for the forseeable future. Pesticides provide tremendous benefits. One estimate was that there is roughly a $4 return for every $1 invested in pesticides. There is simply no way that food can be produced to feed from 6 to 11 billion people that will be on the world in the next 25 years without pesticides without large disruptions to the environment. Pesticides have played a large part in the bountiful harvests that we have received many of the past years. In recent years pesticides have prevented losses to our crops and fungicides have literally saved the North Dakota potato crop from destruction.
There are alternatives to pesticides, these alternatives have advantages over pesticides, disadvantages compared to pesticides, and limits on where, when, and how they will work.
Cultivation works really well, until it rains, and rains, and rains. The performance of many of the alternatives to pesticides such as biological controls is slow acting or erratic. They work well in one situation and poorly in another. The alternatives need to be effective and dependable. They also must be practical and relatively inexpensive. I firmly believe in using an integrated approach to pest management using many strategies and methods including pesticides. Sometimes pesticides are the best solution to a pest problem. They can solve a pest problem quickly, inexpensively, practically, with a minimum of time and effort.
Pesticides vary greatly in characteristics. Many pesticides impose little or no risk on the applicator, other people, animals, plants, or the environment. Many other pesticides impose some level of risk that can be managed safely. There are some pesticides that impose a significant level of risk; these need to be handled carefully only by a properly trained and experienced applicator. Many people are much more afraid of pesticides than they need to be. SOME people need to be much more afraid of pesticides than they are.
The Food Quality Protection Act (FQPA) will place additional pressure on the pesticide registration system. It will be more expensive and more complicated to get a new pesticide registered. That will result in fewer registrations. The registration process will now require products to be reregistered every 15 years. That will result in loss of some products. The need to consider all types of exposure to a pesticide and exposure to all pesticides with the same mode of action will result in the loss of some important pesticides, such as some insecticides in the organophosphate and carbamate families and some of the common fungicides. The net result of this will be fewer pesticide options.
On a brighter side, USDA, EPA, and the North Dakota Pesticide Control Board will be trying to obtain and maintain pesticide registrations for minor uses. USDA and EPA have put in place programs to help obtain and maintain minor use pesticide registrations (see article on page 8). USDA has its IR-4 program which has obtained many very needed pesticide registrations in the past and will continue to do so. In addition the 1997 North Dakota legislature authorized and appropriated a program to obtain pesticide registrations for minor uses in North Dakota. Barry Coleman, with the North Dakota Department of Agriculture, is accepting applications for projects to obtain a pesticide registration for a minor pesticide use. Between the IR-4 and the North Dakota minor use pesticide program the mechanism is in place for growers, pesticide applicators, and commodity or agricultural organizations to become involved in obtaining the registrations that are needed to produce crops in the very competitive world economy that now exists. Pesticide companies will simply not be able to get many of the uses we would like to see registered. USING A PESTICIDE ON A CROP IT IS NOT REGISTERED ON IS NOT AN OPTION, AND IT NEVER WILL BE. YOU MUST take responsibility to determine which uses YOU NEED to control pests and produce the commodities that are grown. Then YOU MUST work hard to obtain that registration. If you do not help, North Dakota will fall behind the rest of the world and become unproductive. If you become involved you can help North Dakota compete successfully in the world economy. YOUR SUCCESS depends on your involvement. Please become involved.
Pesticides do need to be regulated because of potential risks, and both the National Pesticide Law and the State Pesticide Act work pretty well. Pesticide applicators must become more involved in the process of regulation. When applicators have been involved the regulations have been fairly reasonable. When not, the regulations have been impractical or burdensome. Many regulators have become more agreeable to input and reaction from applicators, because they want the new regulations to work. There is also some considerable pressure for agencies to be customer friendly. Take advantage of the opportunity.
One of the regulations that is very well intentioned, but contains significant burden and is not as practical as it should be, is the EPA Worker Protection Standard. When EPA moved to finalize the standard it was told by USDA, state departments of agriculture and other to repropose the standard instead of finalizing it. They finalized the standard. Since then implementation has been difficult. It was even delayed by an act of Congress. The standard is now in place and is being implemented, but there is much room for improvement of this regulation. I hope that you will continue to work with EPA to make the Worker Protection Standard a tool to protect farmworkers from being harmed by pesticides, while making the regulations practical and as unburdensome as possible.
When Congress was considering what to do with the EPA worker protection standard, I was asked by a staff person to make recommendations on how the standard could be improved. I think that some of these suggestions still could be implemented to improve the program. My suggestions follow:
"During the meeting you asked for a letter with suggestions on ways to improve the Worker Protection Standards (WPS) issued by the U. S. Environmental Protection Agency.
"I contacted several individuals representing the North Dakota Department of Agriculture, the NDSU Extension Service, and commercial and private agricultural applicators. What follows is a combination of my ideas and some of the ideas suggested by those individuals.
"Improvement revision no. 1
"There should be an exemption process for any portion of the WPS that is an undue hardship or is unnecessary for the safety of workers or handlers in a particular situation.
"Persons should be able to apply to the State Lead Agency (SLA) for an exemption to or modification of a certain portion of the WPS. The applicant would need to explain why the exemption or modification was being sought and why or how workers would not be placed at risk from pesticides if the exemption or modification was granted. The SLA would have the ability to grant or deny the application. The exemptions should have a time limit, (suggest three years). The exemptions should be renewable, with no limit on the number of times the exemption can be renewed. EPA should be notified by the SLA of the number and type of exemptions or modifications that were granted. EPA should be encouraged to review the exemptions and express to the SLA its opinion about the appropriateness of the exemptions.
"Many of the persons affected by the worker protection standard have had reasonable alternatives to the requirements that have caused the most complaints such as when to wear PPE in certain situations, location of decontamination facilities, posting, displaying application information, and employer information exchange. A process that would allow exemptions would allow persons to fulfill the intent of the regulation, protecting workers from harm, with less burden on the regulated community.
"There will increased acceptance of the regulation because the regulated community has input that is heard and respected in fulfilling the intention of the regulation. Individuals will tend to police themselves locally if some of their own ideas and policies are in place.
"EPA has allowed states to develop state plans to protect groundwater and endangered species, but not for the protection of workers from pesticides. Why?
"Improvement revision no. 2
"Rescind the requirement to display all pesticide application information at a central location from before the application until thirty days after the restricted entry interval has expired. USDA's official comments in the Federal Register Vol. 57, No. 178, on page 42473 were that this requirement would not provide much benefit to workers or handlers as is the case in North Dakota. Information should be made available by employers to workers or handlers about an application or field upon verbal or written request.
"Intermediate solutions could be to exempt employers with fewer than 10 employees from the display requirement and to exempt landgrant universities and private research centers where displaying the information from dozens to hundreds of treatments in some experiments is over-burdensome. The application information should be made available on request.
"Improvement revision no. 3
"Exempt employers from all WPS requirements for those employees that are helping with the mechanical harvesting of a crop after the minimum preharvest interval has expired. The 30 day requirement will cause an unnecessary burden for farmers that hire workers to drive trucks, combines, or harvesters for the harvest season. These farmers must comply with the WPS requirements such as display application information for 30 days, provide pesticide safety training, decontamination facilities, and emergency assistance requirements. The chance of any risk to these farmers' employees from pesticides after the preharvest interval has expired for North Dakota crops is highly remote.
"Improvement revision no. 4
"The requirement for decontamination facilities to be available for pesticide handlers or early entry workers is not unreasonable.
"However, please change the requirement that decontamination facilities be within one-quarter mile of the workers, but not in the treated area for the 30 day interval following the expiration of the restricted entry interval. Many North Dakota fields are large enough that it will be difficult to have the decontamination facility within one-quarter mile of the workers and not be in the treated area.
"The requirement of decontamination facility for the 30 days should be waived. If this requirement is not waived then if the requirement was changed to allow the facility to be in the field or at the end of the field it would not be unreasonable for North Dakota farmers.
"Improvement revision no. 5
"The original worker protection standard had additional requirements on only certain pesticides. The decision to include "all requirements" on "all agricultural pesticides" has caused much of the controversy. There is little disagreement that certain pesticides are more dangerous and need extra protections. There is also a very real concern by persons such as myself that persons will become complacent because all products are affected and workers or handlers may disregard safety measures when the risk is very high.
"A possible solution would be to conduct the worker protection standard only for certain pesticides. According to the USDA comments to EPA in the Federal Register Vol. 57, No. 178 page 42479, only five compounds were responsible for 40% of the pesticide illness incidents in the information USDA was citing. Of the five compounds Phosdrin has been banned by EPA and parathion has had most uses cancelled. Methomyl and propagite are not used in North Dakota. Diazinon, is used only rarely in North Dakota agricultural crop protection. Parathion is still used in North Dakota. North Dakota recognized the need for safeguards and had state regulations in place to prevent harm from parathion to people or organisms in the environment previous to the revised worker protection standard.
"Most pesticides are used without incident. Most North Dakota incidents of illness or injury from pesticides have occurred to the pesticide applicator or someone helping with the application.
"The number of reported incidents has declined from over 200 per year in the early 1980's to between 30 to 40 per year recently.
"EPA could select certain pesticides based upon high risk of pesticide illness or injury or a history of incidents. Lower risk pesticides would be exempted from the more burdensome requirements of the standard.
"Improvement revision no. 6
"The most burdensome portion of the worker protection standard to commercial pesticide applicators is the information exchange requirements. There should be more flexibility in the timing of the information exchange if no other requirements are modified. For example if the grower cannot be contacted prior to the application the notification should be able to be a completed copy of the application record along with the necessary worker protection information at the completion of the application. If the customer was not informed prior to the application then the applicator must not allow persons into the field while the application is taking place.
"In summary, these are possible regulatory revisions to fine tune the worker protection standard to fulfill the intended purpose of protecting workers with a reasonable amount of burden. Revision 1. would allow the states to incorporate and localize most of the other necessary revisions as they see fit.
"Thank you for the opportunity to present these suggestions. I hope that you found this information useful. Please contact me if you have any questions or I can be of further help to you."
Please continue to care about protecting people and the environment from harm. You are the protectors. You protect the crops, food, people, animals, parks, golf courses, wood products, homes, and businesses, from harm. You contribute so much to the economy, environment and the way of life for all North Dakotans. I salute you for your efforts. Please spread the word about the importance of what you do. Help to build trust. Because knowledge and trust are about the only defences of pesticides and pesticide application that really work.
I have had the interesting experience of being in the center of many events, controversies and viewpoints concerning pesticides. I have dealt with people who believe that pesticides present absolutely no risk whatsoever. I have also dealt with people who are desperately afraid of pesticides.
Some of my more unique experiences include:
Concerning ALAR: I remember the phone ringing. When I answered it, a woman asked me if the apple juice she had could be poured down the drain or did it need to go to a toxic waste dump. I was absolutely dumbfounded. As I visited with her about pesticides and pesticide safety she calmed her down considerably. I told her that I planned to keep right on drinking apple juice, that the amount of any pesticide in the juice would be such a low risk as to be zero. BUT, I THINK THE APPLE JUICE WENT DOWN THE DRAIN.
I remember noticing a commercial applicator who was not paying much attention at a pesticide certification meeting. The next time I saw him at a recertification meeting he had lots of questions about how to protect himself from a spray drift lawsuit. I guess he had a teachable moment. Too bad he wasn't more interested earlier.
I really get mad when I think about the dozens of calls I have received over the last nine years from a frightened person who had just had spray drift onto them, their children, pets, livestock, homes or gardens. They are furious and frightened. They do not know if they will die, get sick, or will be OK. These people need to be comforted, provided with information about what they were probably exposed to, decontamination of themselves and their belongings, pesticide toxicity, likely symptoms, effects, and when to go for emergency medical treatment. If you are spraying carelessly . . . KNOCK IT OFF.
I remember the many times that I had to visit with a lawyer representing someone who allegedly was harmed by the mishandling or misapplication of a pesticide, and then the lawyer representing the applicator who was trying to defend his client, the applicator. Please remember that there is more than enough liability when pesticides are involved. You don't need the stress, lost time, and lost money. Think smart and know when not to use a pesticide.
I have really appreciated the hundreds of you (way too many to mention) who have shared with me some situation, practice, or improvement in that you have made to your operation and how it had worked out for you. That filled me with such pleasure. Keep on improving. You have my very best wishes for your success.
(Submitted by Greg Dahl, NDSU Extension Pesticide Programs Specialist.)
[ In This Issue /
Coordinator's Comments ]
[ Law / Insect Control / Disease Control
]
[ Weed Control ]
[ Equipment / Safety / Training ]
ND Pesticide Quarterly, Vol. 15, No. 4 -- October 1997
NDSU Extension Service, North Dakota State University of
Agriculture and Applied Science, and U.S. Department of
Agriculture cooperating. Sharon D. Anderson, Director, Fargo,
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