Garden Chemicals and Intellectual Honesty

Environment, Frontier Centre, Publications, Uncategorized

Background: Early in 2005, based on concerns that weed-killers pose an environmental threat, the City Council of Brandon, Manitoba, was considering an outright ban in that municipality of the products people use to keep their lawns free of unwanted plants. In an article that appeared in the Brandon Sun on March 10, which is reprinted at the beginning of this exchange, the Frontier Centre’s Agricultural Policy Fellow, Rolf Penner, said that those concerns were unfounded and that study after study had proven herbicides to be safe for both man and beast. On March 24, the Sun printed a response to Penner’s views, from Dr. Bill Paton, a professor at Brandon University. Here we present Rolf Penner’s original piece, Dr. Paton’s rebuttal and then Rolf Penner’s point-by-point analysis of it. The exchange provides not only a fair amount of detailed information about herbicides and pesticides, but also a striking demonstration of the importance of intellectual honesty.

1. Opening Round

Weed Killers Eco-Friendly; A ban on lawn-protection products would not be science-based.

By Rolf Penner, Brandon Sun, March 10, 2005

Banning the use of lawn chemicals that control weeds in the city of Brandon is an idea that councillors should flatly reject. Despite the assertions of chemophobes and peddlers of herbicide panic, such bans do nothing to improve public health or the environment. The scientific evidence overwhelmingly confirms their safety.

Claims against herbicides are legion, but they hold about as much water as a hula-hoop. All of the hard science done in the last 50 years, at the cost of billions of dollars, has time and again shown that these weed controllers are benign to the public at large, their pets, their children and the overall environment. They eliminate the specific target that they are designed to control, and that is it.

Take, for example, the herbicide 2,4-D, the oldest and most widely used chemical found in lawn care products today. The toxicology database contains more than 4,000 peer-reviewed, published studies of this compound alone. One done by the U.S. Food and Drug Administration fed massive daily amounts of 2,4-D to dogs for two years. None of the animals developed cancer or any other disease.

The number of truckloads of grass clippings a person would have to eat to match the dosage given to these dogs – where nothing happened – is a physical impossibility. Numerous lifetime mouse and rat feeding trials, as well as multi-generational reproductive studies, have demonstrated similar results. Researchers at the University of Guelph have studied barefoot, barelegged humans who actively walked or sat on turf grass on the day of spraying 2,4-D. They were unable to find any detectable level of exposure.

On February 21, 2005, Health Canada’s Pest Management Regulatory Agency (PMRA) released the results of its latest round of testing on 2,4-D which gave special attention to children and adults in contact with treated lawns and golf courses. It showed that “the use of 2,4-D and its end-use products to treat lawns and turf does not entail an unacceptable risk of harm to human health or the environment.”

Studies can be found which show negative effects to 2,4-D exposure, but on serious inspection they quickly fall apart. One that was recently released by the Journal of the American Veterinary Medicine Association supposedly linked the chemical to bladder cancer in terriers. That breed was chosen because it has shown a genetic predisposition for cancer that makes it 20 times more likely to contract the disease. On top of this deliberate bias, the researchers chose terriers that already had cancer. They based their findings on written questionnaires filled out by owners of these dogs, in which they were asked if they remembered whether or not their dogs might have been on lawns that might have been sprayed with 2,4-D. This sort of study may barely be considered legitimate research; it certainly is not science.

Manitoba’s summers are short. If people would rather spend time outside with their kids, playing baseball or walking their dogs rather than pulling weeds out of their lawns, they should be free to do so. They are not harming themselves, anyone else or the ecosystem if they make this choice, and have no reason to feel guilty if they do.

City councillors may be tempted to jump on the politically correct anti-herbicide bandwagon. But this would be a disservice to the community. Caving in to the arbitrary demands of eco-theologians who substitute personal prejudices and junk science for rigorous, rational, evidence-based conclusions would set a regrettable precedent for Brandon. Councillors should say, “No.” Not to lawn-care products, but to ecological fanatics.

Rolf Penner operates a hog farm near Morris, Manitoba, and is the Agricultural Policy Fellow with the Frontier Centre for Public Policy in Winnipeg.

2. Dr. Bill Paton’s Response

BU Scientist Zaps Notion of Eco-Friendly Weed Killers

By Dr. Bill Paton, Brandon Sun, March 24, 2005

In my course on Environmental Health at Brandon University, I encourage students to improve their critical thinking skills and in the light of Mr. Rolf Penner’s letter to the editor Weed Killers Eco-Friendly (March 10), I would also ask your readers to apply the same common sense skills to the discussion of the cosmetic use of pesticides in our community. The Brandon and Area Environmental Council is pleased to provide published scientific and medical information to the public to assist in this debate.

First of all, do your own reading and research, do not rely upon the word
of Mr.Penner.

What are pesticides? They are chemical\physical agents used to kill or control pests-insects, weeds, fungi, rodents, birds etc. These substances interact with the metabolism of these organisms to inhibit or kill them. A fundamental principle in biology is the unity of biochemistry- that is, the metabolism of all organisms share [sic] common bio-chemical pathways. There is therefore a strong possibility that a chemical that kills an insect, fungus or weed may also affect the growth and development of other plants and animals.

Indeed a number of the formerly recommended pesticides (captan, chlordane, benlate, DDT, etc) have had their registrations withdrawn because of their effects on human health or cancer causing properties.

What are Mr. Penner’s qualifications and research experience in the area of pesticides and their impacts on ecosystems and biota? Mr.Penner has a diploma in agriculture and is a farmer. He has been an avid propagandist for the hog industry in the province, espousing its benign impact on the environment. His credibility in this area is therefore minimal, relying on hearsay and propaganda from the proponents of spray and pray agriculture which current biological knowledge and modern agricultural ecology clearly indicates is on its way out.

Indeed, the City of Brandon no longer sprays boulevards for dandelions for both economic reasons and the reality that these plants have developed resistance to the herbicides at recommended rates. Despite many years of attack they are ever present in the city and the countryside around. Those who continue to use these products in our city are negatively impacting other plants in our community.

It is notable that Mr. Penner makes great generalizations but cites no specific references to substantiate his claims of absolutely no impacts of pesticides on human or ecosystem health. This despite an extensive body of literature linking the phenoxy-acetic acid herbicides to soft tissue sarcomas and non-Hodgkins lymphoma.

However, as in any epidemiological study involving small populations and often recall analysis, critics can raise questions about the conclusions. The introduction of meta-analysis allows one to take a large number of different studies on this issue and conclude that indeed there is significance to the linkage between this group of herbicides and these cancers.

It is also clear that there are individuals in the Brandon population who experience serious health consequences from drift of such agents into their environment. Chemical sensitivities are a reality of our modern world and clearly society has a responsibility to protect these citizens from foreign chemicals that impact on their living space and health.

Examinations of the Material Safety Data Sheet for 2,4-D indicates very clearly that it is a respiratory irritant. Statistically significant links between phenoxy acetic acid herbicide exposures and suicide have been reported among hydro workers in Ontario using the herbicides to clear transmission lines. 2,4-D has also been also shown in laboratory studies to influence the level of the natural substance serotonin, well linked to depression and mental well-being. Associations with miscarriages and fetal development have also been reported.

Following the introduction of 2,4-D and its analogues in the 1940’s there is a long history of impacts on broad-leaved crops and ornamentals. Indeed in the shelterbelts trails in the 1930’s the Manitoba Maple was found to be the best shelterbelt tree throughout much of the prairies and the Midwest USA. However, with the advent of 2,4-D, this tree was found to be severely damaged by drift and of reduced value in shelterbelt programs in the region. Due to continued damage to sunflowers, vegetables and ornamentals through the 1950’s and early 60’s the most volatile ester formulations of the herbicide were withdrawn by the manufacturers or prohibited by provincial or state governments.

2,4-D is a herbicide developed from the natural plant growth regulator indole acetic acid. Eighty–plus years of research on IAA have demonstrated that auxin can have a role in all aspects of plant growth and development, hence it is not surprising that the effects of the phenoxy-acetic acid herbicides on other plants are extremely complex. Indeed our research in the past 20 years on this problem on the Prairies has uncovered dramatic negative impacts on the flora and fauna. The emergence of 2,4-D resistant mustard and weed resistance to a number of other herbicides in the province has also illustrated the folly of dependence on simplistic chemical approaches.

When we look at the big picture, more and more of the pesticides that have been traditionally used by gardeners in the city and region are being deregistered by the manufacturers. Why? Because the market in Canada for these products is declining as major communities across the country go pesticide free and the companies themselves acknowledge that the new approaches to dealing with pest problems are necessary. The development of biological controls, disease resistant crop varieties and the application of principles of integrated pest management have become the new focus of modern agribusiness companies interested in truly sustainable food production.

Bill Paton teaches Enviromental Health at Brandon University and is president of the Brandon and Area Environmental Council.

3. Discussion

Rolf Penner responds:

BU Scientist Zaps Notion of Eco-Friendly Weed Killers
By Dr. Bill Paton

In my course on Environmental Health at Brandon University, I encourage students to improve their critical thinking skills and in the light of Mr. Rolf Penner’s letter
to the editor, “Weed Killers Eco-Friendly” (March 10), I would also ask your readers to apply the same common sense skills to the discussion of the cosmetic use of pesticides in our community. The Brandon and Area Environmental Council is pleased to provide published scientific and medical information to the public to assist in this debate.

Rolf Penner: Good luck to the public in finding the Council. They do not have a website and are not listed in the phonebook or under directory assistance.

First of all, do your own reading and research, do not rely upon the word of Mr. Penner.

RP: Good advice. Don’t take the word of Dr. Paton, either.

What are pesticides? They are chemical\physical agents used to kill or control pests–insects, weeds, fungi, rodents, birds etc.

RP: Not quite true, pesticide is an umbrella term, which includes herbicides to control plants, insecticides to control insects and fungicides to control fungus. Products to control rodents and birds do not fall under this umbrella.

These substances interact with the metabolism of these organisms to inhibit or kill them. A fundamental principle in biology is the unity of biochemistry¯that is, the metabolism of all organisms share common bio-chemical pathways. There is therefore a strong possibility that a chemical that kills an insect, fungus or weed may also affect the growth and development of other plants and animals.

RP: This is a disproved speculation, which is why it contains the qualifier, “strong possibility.” It is based on the fact that all of the countless, diverse forms of life on the planet share similar genes. For instance 98.6 percent of the genes in chimpanzees are identical to humans. Even so, we all know that there are big differences between chimps and humans. So it is with plants, animals, bugs and us. It is a simple thing to test for the effects of chemicals on non-target organisms, and such testing has been done thoroughly and extensively for over 50 years. Paton’s statement falls apart when tested. A plant is not a bug, is not a rat and is not a boy.

A good example is the chemical compound, dioxin. The tiniest amount of this substance is capable of “taking out” a guinea pig, but it takes at least 5,000 times that dose to kill a much smaller hamster. This difference in reaction is what saved the life of Ukrainian presidential candidate, Viktor Yushchenko, when he was purposefully poisoned with a massive dose of dioxin. The would-be assassins did not do their homework; they relied on junk science.

Paton here attempts to smuggle environmental ideology into a scientific discussion. His position suffers from a logical fallacy, a syllogistic error known as the “undistributed middle.” The argument is: “If A kills B, and B is somehow similar to C, A therefore kills C.” The argument is false.

Indeed a number of the formerly recommended pesticides (captan, chlordane, benlate, DDT, etc.) have had their registrations withdrawn because of their effects on human health or cancer-causing properties.

RP: Dr. Paton should do his homework.

Captan, a fungicide, was reclassified by the American Environmental Protection Agency (EPA) on November 24, 2004. But the text of the EPA’s decision to move captan into the category of “probable human carcinogen” tells the tale. Captan, the EPA stated, is still just “a potential carcinogen only at prolonged high doses that are significantly greater than those likely to be consumed in the diet or encountered in occupational or residential settings. The Agency has concluded that captan is not likely to be a human carcinogen or to pose cancer risks of concern when used in accordance with approved product labeling.” It is still registe
red for use.

Chlordane, an insecticide, has been banned since 1988. That decision, however, resulted not from its harmful effects but from the compound’s chemical stability. It breaks down very slowly and can remain in the soil for more than 20 years. Pesticides in which the active ingredients neutralize and break down quickly after use are now favoured. Adverse health effects occur only when people breathe air containing high concentrations of chlordane, as in a house has just been fumigated for termites, or when they accidentally swallow small amounts of it. The International Agency for Research on Cancer has determined that chlordane is not classifiable as to its carcinogenicity for humans. Studies of workers who made or used chlordane do not show that exposure to chlordane is related to cancer.

Benlate, a fungicide, has never been shown to have any negative effect on human health or cause cancer. In fact, it is of such a low acute toxicity to mammals that it has been impossible or impractical to administer doses large enough to firmly establish an LD50, which is the common measuring stick for toxicity. The product’s withdrawal from registration occurred in response to numerous lawsuits brought against its manufacturer, and those actions had nothing to do with safety. They stemmed from the fact that some lots of the product in 1989 and 1991 were accidentally contaminated with the herbicide atrazine, which caused unintended crop damage. The lawsuits didn’t stop after the problem with contamination was rectified, and the company dropped the product to halt the endless, unfounded litigation it was facing. That was unfortunate, because benlate is an extremely safe and effective product.

DDT, an insecticide, has never been shown to have negative effects on human health. On the contrary, as the most effective agents for controlling disease-spreading insects, it served as one of the greatest public health tools of the 20th century. However, overuse harmed its efficacy. That made it politically unpopular, as did Silent Spring, the famous book by Rachel Carson that indicted DDT for weakening the eggshells of birds. Carson’s claims have since been refuted. According to the Journal of Cancer Research and Clinical Oncology, feeding primates more than 33,000 times the average daily human exposure to DDT (as estimated in 1969 and 1972) was “inconclusive with respect to a carcinogenic effect of DDT in nonhuman primates.”

What are Mr. Penner’s qualifications and research experience in the area of pesticides and their impacts on ecosystems and biota? Mr.Penner has a diploma in agriculture and is a farmer. He has been an avid propagandist for the hog industry in the province, espousing its benign impact on the environment. His credibility in this area is therefore minimal, relying on hearsay and propaganda from the proponents of spray and spray agriculture which current biological knowledge and modern agricultural ecology clearly indicates is on its way out.

RP: Dr. Paton has some nasty bones in his body. Here he uses more logical fallacies to express himself. The first is argumentum ad hominem, or attacking the person. In this case the fallacy, which in debating circles is generally considered unsportsmanlike and which some consider as cause for immediate disqualification, mixes personal attacks with outright falsehoods. It is characteristic of people taking weak logical positions that they attack the person presenting the argument rather than the argument itself.

The second fallacy, contained in the statement “current biological knowledge and modern agricultural ecology clearly indicates [spray and spray agriculture] is on its way out,” is argumentum ad verecundiam, or appeal to authority. Not only do experts in the field disagree on this point, but the position taken by Paton is a minority one. The website of the Center for Global Food Issues (at http://www.highyieldconservation.org/signers.php) contains a “Declaration of Support for Protecting Nature with High Yield Agriculture and Forestry.” Among others, its signatories include Noble Prize winners Dr. Norman Borlaug, Ph.D., the “Father of the Green Revolution,” and Oscar Arias, Ph.D, and world food prize winner, Per Pinstrup-Andersen, Ph.D. In this case, Dr. Paton’s appeal to authority is not just fallacious but dishonest, because he fails to include other, majority perspectives that disagree with his.

The third fallacy, which is the source of the others, is what is known as “the argument from intimidation”. It is best illustrated by the classic story, “The Emperor’s New Clothes.” How dare a lowly dirt farmer of limited education challenge the assertion of an obviously superior intellect, which is self-evident by virtue of a name beginning with the letters “Dr.” and ending in “Ph.D.” Simply put, this farmer boy maintains that the emperor has no clothes, and the good professor has few facts.

I have made it clear that my credentials, as with Dr. Paton’s, are not relevant to the evidence or the arguments presented here. Since he has chosen to make them an issue, however, and may be of interest to some, I gladly share them. I do indeed have a diploma in agriculture that I received at the University of Manitoba in 1988. The diploma program focuses on the practical application of science related to agriculture. I was taught by many different professors far more qualified than Dr. Paton, on a much broader range of subjects than merely botany.
I am also a full-time farmer and have been all my life. As such, I have a lifetime of hands-on experience with all three categories of pesticides, which I have now used on tens of thousands of acres of cropland. This makes my research experience on pesticides and their impacts on ecosystems and biota extensive and evidence-based, rooted in the real world not a laboratory. This is not to say that one is superior to the other; they both have their place. In addition to this I am currently the Agricultural Policy Fellow for the Winnipeg-based indepen
dent think-tank, the Frontier Centre for Public Policy, where I research issues like the banning of the cosmetic use of pesticides.

Further, even though I never studied English literature, I am still somehow able to find Shakespeare in the library, am able to read it and even quote from Hamlet. The fact that I lack a Ph.D. in English literature says nothing about my ability to appreciate thoughts from the great bard or to analyze his lines critically.

If one were inclined to apply Dr. Paton’s standard of the qualifications and experience necessary to engage in a discussion to him, what would one discover? That he was “born in Kilwinning, Scotland and received his Bachelor of Science from the University of Strathclyde, Scotland and his Master of Science and Ph.D. in Biology from Queen’s University in Kingston, Ontario. He is currently a Professor of Botany at Brandon University in Manitoba and his research interests include tree decline, alternative energy (ethanol/butanol), transport processes, solid waste management/composting, sewage sludge, pollution biology (wastewater treatment, environmental monitoring), biomass energy crops and horticulture (greenhouse, hydroponics).”
His biography contains no mention of any credentials related to pesticides, nor are pesticides mentioned in his “research interests.” A web search of his peer-reviewed, published studies of any kind comes up blank. He may have done such studies but, if so, they are not readily available or easy to find. A scientist who does not have credit for any such studies is like a farmer who never harvested a crop. His opposition to the use of chemicals is, I suggest, a product of ideology, not independent science.

Paton is not a medical doctor and has no medical background. Neither is he a toxicologist or an epidemiologist. He has never worked for any of the regulatory bodies, which test and approve the chemicals in question. He has never been involved in developing an herbicide or taking it all the way from the laboratory stage through registration and into commercial use.

In fact, a cursory investigation of Dr. Paton reveals that he is an activist academic who has been more than willing to lend his Ph.D. credentials to any number of causes. He was opposed to the construction of the successful Maple Leaf slaughter plant in Brandon, and to a proposed second shift at the facility. He has campaigned against the PMU industry, hog barns and sewage lagoons. He regularly works with extremist organizations like Hogwatch and the Sierra Club. In the Spring, 2003, edition of the Sierra Club Activist News, he is on record as saying that, “If you smell hog manure, molecules of ammonia and phosphorus are entering your lungs.” The article claims that anyone who gets a whiff of a hog barn is at high risk for getting asthma. There is zero evidence for this claim; it is science fiction.

All this raises serious questions about Dr. Paton’s credibility on the subject at hand, and his overall general lack of commitment to the scientific method. If you think that neither Paton nor myself are qualified enough to comment on the issue, how about Sir Richard Doll, professor emeritus of cancer research epidemiology at Oxford University? At a meeting in Guelph, Ontario, when a local municipal politician asked Sir Richard if there were a connection between the use of pesticides and cancer, and if a ban was warranted on the use of lawn and garden pesticides, he responded, “No. There’s no scientific basis for it.” The argument from authority cuts both ways.

Indeed, the City of Brandon no longer sprays boulevards for dandelions for both economic reasons and the reality that these plants have developed resistance to the herbicides at recommended rates.

RP: I don’t know why the City of Brandon chose to stop spraying boulevards for dandelions, but I seriously doubt that herbicide resistance is the reason. There is more than one herbicide available to control them, and I’m sure that a qualified specialist who knew how to rotate herbicides properly was hired to oversee these control measures.

Despite many years of attack they are ever present in the city and the countryside around. Those who continue to use these products in our city are negatively impacting other plants in our community.

RP: This is a common argument from the anti-pesticide crowd. Why is it that the offending plants are still around? The products must therefore not work. This line of reasoning is false.

The products only control the plants actually sprayed if they are at exactly the right growth stage. If a plant is too small or conversely too large, the herbicide may be completely ineffective. Since the growth stages of weeds across a field or ditch are never completely uniform, it is impossible to time an application perfectly. The plants that survive set seed, and it does not take a lot of plants to make a lot of seed, which of course leads to more plants. On top of this, plants outside the spray zones continue to propagate and the seeds from these plants migrate all over thanks to animals, birds, insects and the wind. Weeds will never be eliminated. They can only be temporarily controlled. That says nothing about the effectiveness of the chemical agent in use.

Ecologists and environmentalist who harp on the importance of bio-diversity should be pleased by this. I doubt they would really be happier if we made certain species of plants extinct. This is what is called a self-cancelling argument. Another question that begs asking is, “If there are farmers who never made it past junior high who understand this weed cycle perfectly, why is it that a professor of botany does not?” The question answers itself.

It is notable that Mr.Penner makes great generalizations but cites no specific references to substantiate his claims of absolutely no impacts of pesticides on human or
ecosystem health.

RP: I invite the reader to review my original article “Weed Killers Are Eco-Friendly,” which is reprinted above. Take particular note of paragraphs three, four, five and six, where I reference a U.S. Food and Drug Administration study, a University of Guelph study, results from Health Canada’s Pest Management Regulatory Agency and a bladder cancer study from the Journal of the American Veterinary Medicine Association.

This despite an extensive body of literature linking the phenoxy-acetic acid herbicides to soft tissue sarcomas and non-Hodgkins lymphoma.

RP: Could the good professor generalize less and be more specific in his references?

There are over 140 epidemiological studies regarding 2,4-D. The studies most frequently cited by activist groups are the National Cancer Institute’s Kansas (1986) and Nebraska (1990) farm worker studies, both of which received considerable media attention. NCI’s larger and more recent Iowa/Minnesota study, which showed no association between 2,4-D and cancer, has been generally ignored by the media, as has the latest NCI case-control study (A. J. DeRoos et al., in the Journal of Occupational and Environmental Medicine, 2003). For some reason, those on Dr. Paton’s side of this issue never cite the latter two studies.

The Kansas study did not develop data specific to 2,4-D, but dealt with general herbicide use. It suggested a higher risk of non-Hodgkin’s lymphoma (NHL) among farmers who applied herbicides 21 days a year or more. The Nebraska study showed a statistically non-significant risk (not outside the realm of chance) of NHL among farmers applying 2,4-D for 21 days a year or more. The Kansas study showed that the highest risk of NHL was among farmers who had applied herbicides prior to 1946. But 2,4-D was not registered for sale as an herbicide until 1947. In the real world, there were no farmers in Kansas who had applied 2,4-D prior to 1946.

All three studies relied on information provided by proxy respondents. In many cases, the person chosen to participate in the study was not available, so next-of-kin or neighbours were asked about the unavailable person’s pesticide use over a previous period of more than forty years. Is this scientific? Of course not, and in the NCI Nebraska study when the information provided by the self-respondents, the farmers themselves, is analyzed separate from the information given by neighbors or next-of-kin, no association between 2,4-D and cancer was found (G. W. Olsen et al., Journal of Agromedicine, 1996).

The U.S. National Cancer Institute has spent 20 years and millions of dollars testing for any link between 2,4-D and non-Hodgkin’s lymphoma. Its analysis concluded that there is no association between non-Hodgkin’s lymphoma and “ever having used 2,4-D.” One of the more recent cohort studies pertinent to 2,4-D was conducted by the University of Miami School of Medicine, which concluded, “In a cohort of 33,669 Florida pesticide applicators, there were 1,266 incident cancer cases with 316,226 person-years from 1/1/75 to 1/1/94. In the SMR and Cox proportional hazard analyses, these workers were significantly healthier compared with the general Florida population for overall cancer incidence. There were no confirmed cases of soft tissue sarcoma, and non-Hodgkin’s lymphoma was not increased.” (L. E. Fleming et al., “Mortality in a cohort of licenced pesticide applicators in Florida,” Journal of Occupational and Environmental Medicine, 1999). Those interested in further information should look at a report from Purdue University Pesticide Programs from July, 1998, titled, “Pesticides and Epidemiology: Unraveling Disease Patterns.”

However as in any epidemiological study involving small populations and often recall analysis, critics can raise questions about the conclusions. The introduction of meta-analysis allows one to take a large number of different studies on this issue and conclude that indeed there is significance to the linkage between this group of herbicides and these cancers.

RP: Meta-analysis, a mainstay of junk-science pushers, takes a bunch of poorly done studies like the ones above, disregards the rigorously tested ones that don’t support a pre-determined conclusion and mixes them all together. What do you get? A really big study that is even less reliable than the ones that make it up. It doesn’t matter how much garbage you pile together or how big the pile gets, it’s still a pile of garbage.

It is also clear that there are individuals in the Brandon population who experience serious health consequences from drift of such agents into their environment.

RP: That sounds serious. Would be too much trouble for Dr. Paton to point out some actually documented cases? It turns out that would be a lot of trouble, because there are none.

Chemical sensitivities are a reality of our modern world and clearly society has a responsibility to protect these citizens from foreign chemicals that impact on their living space and health.

RP: If that’s the case, why have all the following groups, to name but a few, rejected multiple chemical sensitivity as a legitimate organic disease? The list includes: the American Academy of Allergy and Immunology, the Board of the International Society of Regulatory Toxicology and Pharmacology, the American Medical Association, the American Medical Council on Scientific Affairs, the American College of Physicians, the American College of Occupational and Environmental Medicine and the American Academy of Allergy, Asthma and Immunology.

Perhaps it is because they are not botanists at the University of Brandon. Iowa University Medical Center psychiatrist Dr. Donald Black, who has studied multiple chemical sensitivity for many years, has a better explanation: “The conclusion I draw is that almost all studies have found an excess of mental illness in these individuals.” Paton’s statement also ignores the fact that we are exposed to far more naturally occurring toxins than manmade ones. According to Professor Bruce Ames of the University of Berkeley, probably the world’s most respected authority on the subject, 99.99 percent of the pesticides we consume are natural; only .01 percent are synthetic.

Comparing levels of carcinogens in our environment turns up some interesting facts. Did you know, for instance, that our average intake of coffee, for example, is 66 times more carcinogenic than that of the most dangerous present-day pesticide, ETU? That substance, by the way, is not found in lawn care products.

Examinations of the Material Safety Data Sheet for 2,4-D indicates very clearly that it is a respiratory irritant.

RP: Run for the hills, you may be at serious risk of getting a tickle in your throat. What the sheet actually says under “Health Hazards” is: “INHALATION: May cause moderate respiratory irritation.” You have to suck in a whole lot of it before you even get to that point. The EPA has stated in its Toxicological Endpoint Selection Document, ”Exposure via inhalation is not a concern.”

Statistically significant links between phenoxy acetic acid herbicide exposures and suicide have been reported among hydro workers in Ontario using the herbicides to clear transmission lines. 2,4-D has also been also shown in laboratory studies to influence the level of the natural substance serotonin, well linked to depression and mental well-being.

RP: Talk about theater of the absurd! This claim certainly doesn’t pass the common sense test, or the most fundamental rule of epidemiology, namely, that correlation is not causation. Logically, this statement is an example of the fallacy called post hoc, ergo propter hoc, in English, “after this, therefore because of this.”

Sure enough, studies have tried to link herbicide use to suicides. But the professor has an interesting take on what is “statistically significant.” The study to which he refers is part of an international one that comprised 36 cohorts from 12 countries, followed from 1939 to 1992 and compiled by 18 authors. One of those cohorts came from Canada, and was based on Ontario Hydro workers. The overall conclusion of the study was that, “Mortality from suicide was comparable to that for the general population for all workers exposed to herbicides.” So a study that shows no difference is somehow considered statistically significant to Dr. Paton.

Associations with miscarriages and fetal development
have also been reported.

RP: The 114 research studies completed under the recent re-registration program confirm the existing toxicology data package. They reconfirmed that 2,4-D has low reproductive toxicity and does not cause birth defects.

Following the introduction of 2,4-D and its analogues in the 1940’s there is a long history of impacts on broad-leaved crops and ornamentals.

RP: Imagine that. A herbicide designed to control broadleaf plants actually controls broadleaf plants.

Indeed in the shelterbelts trails in the 1930’s the Manitoba Maple was found to be the best shelterbelt tree throughout much of the prairies and the Midwest USA. However, with the advent of 2,4-D, this tree was found to be severely damaged by drift and of reduced value in shelterbelt programs in the region. Due to continued damage to sunflowers, vegetables and ornamentals through the 1950’s and early ‘60’s the most volatile ester formulations of the herbicide were withdrawn by the manufacturers or prohibited by provincial or state governments.

RP: The more volatile esters where never prohibited by any government; that statement is false. There was never any great concern about damage to non-target plants, but since the research into the product was ongoing and scientists were able to develop a less volatile, safer formulation, manufacturers quite understandably switched to them.

2,4-D is a herbicide developed from the natural plant growth regulator indole acetic acid. Eighty–plus years of research on IAA have demonstrated that auxin can have a role in all aspects of plant growth and development, hence it is not surprising that the effects of the phenoxy-acetic acid herbicides on other plants are extremely complex.

RP: Translation: Despite using every test known to man for decades, we haven’t found any such effects. So we should base our decisions on what we don’t know, and can’t test for. The logical fallacy here is argumentum ad ignorantiam, the argument from ignorance. It’s like saying since you cannot prove that ghosts do not exist, they must exist. Lack of proof is not proof of anything.

Indeed our research in the past 20 years on this problem on the Prairies has uncovered dramatic negative impacts on the flora and fauna. The emergence of 2,4-D resistant mustard and weed resistance to a number of other herbicides in the province has also illustrated the folly of dependence on simplistic chemical approaches.

RP: What would a gallery of logical fallacies be without a “straw man” argument? The existence of herbicide-resistant weeds is irrelevant to the topic at hand. It simply shows how complicated chemical weed control actually is, because it has to deal with plant evolution as well.

When we look at the big picture, more and more of the pesticides that have been traditionally used by gardeners in the city and region are being deregistered by the manufacturers. Why? Because the market in Canada for these products is declining as major communities across the country go pesticide free . . .

RP: That’s not true. Communities are not going pesticide free. Because a municipality decides it wants to ban pesticides doesn’t mean it can make that happen. In Toronto, for instance, residents are still able to purchase all the pesticides they want at local stores because they have been federally approved. The city has no jurisdiction in that area. These bans are essentially social statements and not much more. Enforcement on a residential basis is practically impossible and would be terribly expensive. The products break down so quickly and the residue tests required for actual proof are so expensive that no municipality has bothered to pursue the matter.

As to the market declining, Dr. Paton has once again neglected to do his homework. According to the Croplife Canada annual report, non-agricultural herbicide sales in Canada increased 16 percent in 2003 over 2002. Despite all of the politically correct hoopla around pesticides, Canadians are in favour of them now more than ever.

. . . and the companies themselves acknowledge that the new approaches to dealing with pest problems are necessary. The development of biological controls, disease resistant crop varieties and the application of principles of integrated pest management have become the new focus of modern agribusiness companies interested in truly sustainable food production.

RP: Again, this is not true, but I thought we were talking about the cosmetic use of pesticides. The professor shamefully concludes his attack with another straw man argument