The Quebec Poison Control Centre and the Quebec Ministry of Environment and Wildlife released statistics on pesticide poisoning in 1996. They reported a staggering 1,650 poisoning cases. 79.4% of the cases were in private homes, and 46.1% of the victims were children under age five. 31% of these cases were due to oral ingestion, and 34.9% followed a pesticide application (1).
What are Pesticides?
Pesticides (herbicides, vermicides, fungicides, and rodenticides) are poisons designed to kill insects, plants, fungi, moulds and rodents. Pesticides contain “active” ingredients (the chemicals intended to kill), and so-called “inert” ingredients. These are considered trade secrets, and although in many cases they can be even more toxic than “active” chemicals, most consumers are completely unaware they exist. Even when used as directed, pesticides have many negative side effects on human health and the environment.
Does “Registered” Mean Safe?
Although pesticides used and sold in Canada are registered, this does not mean they are safe. Even the federal government regulators do not claim that registration equals safety. Pesticides are not tested in combination, although their synergistic effects may be amplified as much as 1000 times. While pesticides produce acute and long-term health effects, toxicity experiments (done on healthy animals) measure and account for only the acute effects. The pesticides that are deemed acceptable for use as a result of these tests do not take into account the possible chronic effects (2). “Acceptable” tolerance levels are set for an average adult male, and do not take into account the different situations of women and children.Some Environmental Effects Some pesticides accumulate in the fatty tissues of mammals, amphibians, birds and fish, interfering with their growth, reproduction and behaviour. Pesticides poison the food chain, contaminate water supplies, and are implicated in the declining populations of certain species.
What are the Health Effects?
Acute Effects: The Canadian Centre for Occupational Health and Safety has identified acute health effects in humans including nausea, eye, skin, respiratory and throat irritation, muscle spasms, and even death (3).
Chronic effects: Repeated exposure to pesticides has been linked to neurological problems, brain and lung cancer, immune suppression (which creates environmental hypersensitivity), leukaemia, Parkinson’s disease, kidney damage, non-Hodgkin’s lymphoma and reproductive disorders, including endocrine disruption, low sperm count, and sterility(4).
Children are Vulnerable: Pound for pound of body weight, children consume considerably more pesticides than adults. Kids are especially vulnerable to the toxic effects because their metabolic systems don’t process or excrete toxins the way adults’ systems do. Children typically play in grass and dirt, and put toys and hands in their mouths, activities that significantly increase their exposure to pesticides. Children from homes where pesticides are used have been found to have four times the risk of soft tissue sarcomas (cancerous growths (5) and between six and seven times the rate of childhood leukaemia as other children (6).
Sweden Has Not Allowed
2,4-D Since 19892,4-D is the most commonly used herbicide in Canada. It was a major component of Agent Orange, and is still used in over 1,500 lawn-care products (including Killex and Weed ‘n Feed). Cancer in dogs has been linked to their owners’ use of 2,4-D (7).
“ Insects...are the most important component of the ecosystem, an integral part of the food chain...without insects the vast majority of flowering plants would not be able to reproduce. A miniscule fraction of this huge group of animals are pests to human beings….spraying powerful poisons that kill all exposed insects is no more ‘management’ of pest than killing everyone in New York city would be managing urban crime.” David Suzuki – The folly of Chemical Pest Control
The Pesticide Treadmill
Once you begin to apply pesticides, your lawn can become addicted to chemical treatment. Repeated applications can cause soil to become conditioned, which speeds up degradation of the pesticides. This results in the need to apply increasingly toxic chemicals at more frequent intervals to control the pest problem. Meanwhile, beneficial organisms are killed off, soil can become sterile, and pesticide-resistant insects breed to produce a species able to withstand the toxins and continue eating your grass!
References
1. Centre Anti-Poison du Quebec, Rapport annuel 1996: statistiques sur les intoxicantions par les pesticides, April 1997.
2. National Coalition Against the Misuse of Pesticides, Lawn pesticide facts and figures, NCAMP, San Francisco, US, 1992.
3. Canadian Centre for Occupational Health and Safety bulletin, Ottawa,1990.
4. Environment Canada, Pesticides, the right amount. Ottawa, 1989.
5. American Journal of Public Health, “study suggests possible link of child cancer, home pesticides”. Ottawa Citizen, Feb.27, 1995.
6. Journal of the National Cancer Institute.
7. Hayes et al., Journal of the Nation Cancer Institute vol.83, 1991.
Pesticide Reduction
Pesticides in Canada are widespread and commonly used in households- yet few Canadians are informed about the negative effects of these chemicals. Pesticide regulation in Canada is seen as inadequate by many and pesticides are promoted as “safe”; the risks associated with their use minimized. The continued use of pesticides in Canada contributes to a build-up of harmful chemicals in the environment.
According to Canadian studies, DDT and DDE residual levels in the breast milk to Inuit women in the Eastern Arctic are 1210 parts per billion, compared to 171 parts per billion in women in Southern Ontario. The extreme levels of persistent pesticides in Arctic people and animals high on the food chain are largely a result of transboundary transport and bioaccumulation. Similar build-ups of other harmful pesticides have been recorded in various parts of Canada including the Great Lakes, the St. Lawrence River and the Prairies.
Over 34 million kilograms of pesticides are used annually across Canada. According to the National Research Council, expenditures on pesticides have doubled between 1980 and 1990 and have increased eightfold since 1970.
The negative effects of pesticides in the Canadian environment are already evident and well documented. For example, autopsies performed on a group of Canada Geese that died inexplicably near Simcoe Ontario in September 1996 revealed that the grass and clover found in their digestive systems contained diazinon-a lethal chemical used on lawns. The birds were reported to have been behaving erratically and showed signs of blood in the feces and mucus streaming from their mouths.
In another incident in Manitoba, a 13 kilometer stretch of trees was wiped out by the chemical Roundup (a broadleaf pesticide, chemical name glyphospate) that was sprayed on nearby fields. Roundup is promoted by industry as a safe pesticide, despite the fact that it has proved to be far more toxic than its initial registration revealed.
The Health and Environment program area’s Pesticide Reduction program works directly with the federal government on pesticide issues through many stakeholder committees including the Pest Management Advisory Council and the Healthy Lawns Labelling Subcommittee.
2,4-D
Dichlorophenoxyacetic Acid
General
2,4-D is a very popular lawn care pesticide in Canada and according to American manufactures, 2,4-Dichlorophenoxyacetic Acid (2,4-D) is the most widely used herbicide in the world.[1] It is sold under a variety of product names including numerous “weed and feed” lawn care products. A chlorinated phenoxy herbicide, 2,4-D is unique in that it causes a variety of different effects to the nervous system.
How It Works
2,4D is a growth inhibitor. It is absorbed into a plant through the plant’s surface. The weed killer circulates through all parts of the plant mimicking hormones called auxins which control numerous development and growth processes[2]. It causes abnormal growth, blocking the passage of liquids and nutrients. Subsequently, the roots starve and the plant dies.[3]
Health Effects
In mammals, 2,4-D disrupts energy production[4], depleting the body of its primary energy molecule, ATP (adenosine triphosphate)[5] 2,4-D has been shown to cause cellular mutations which can lead to cancer. This mutagen contains dioxins, a group of chemicals known to be hazardous to human health and to the environment[6].Documented health problems relate to 2,4-D include reproductive damage(i.e. sterility), respiratory difficulties, atrophy, nausea, loss of appetite, skin rashes, eye irritation, and chronic headaches[7]. Non-Hodgkins lymphoma has also been associated with 2,4-D exposure[8]. Furthermore, there is evidence of teratogenicity (birth defects) and mutagencity (mutation of cells) provided by studies involving 2,4-D and lab animals[9].Workers applying chlorinated phenoxy herbicides frequently have nervous system disorders, are exposed to a higher risk of soft tissue sarcoma, and show symptoms of hormonal and internal organ irregularities.[10][11] A study of farmers in Alberta, Saskatchewan and Manitoba linked use of 2,4-D to an increased incidence of prostate cancer.[12]In the urban setting, it has been proven that households using 2,4-D put their dogs at twice the risk of developing canine malignant lymphoma.[13]These risks are elevated when one discovers that homeowners using 2,4-D are likely to track the pesticide into their home where it is expected to persist for up to one year.[14]
Environmental Effects
2,4-D is a moderately persistent chemical with a half-life between 20 and 200 days. Unfortunately, the herbicide does not affect target weeds alone. It can cause low growth rates, reproductive problems, changes in appearance or behaviour, or death in non-target species.Additionally, the spraying of 2,4-D often, contaminates ground water systems because of its very high mobility in soils and weak binding to soil particles[15]. About 91.7% of 2,4-D will eventually end up in water.[16] This contamination threatens the vegetation and the animal life that consumes it. The chemical will also be carried by run-off into the local river systems, thereby jeopardizing the health of aquatic life as well.
Who Uses 2,4-D?
The pesticide is used primarily by cereal crop producers. The forestry industry uses 2,4-D to suppress the growth of hardwoods and undergrowth in conifer plantations. Another application of 2,4-D occurs along major rights-of-ways (i.e. railway tracks) to control brush. In urban areas 2,4-D is applied to control broad leafed weeds such as dandelions, ragweed, and poison ivy[17]. It is the active ingredient in readily available weed control mixtures, for example, killex.
Conclusions
The federal government is currently completing a final review of toxicological data for the pesticide 2,4-D. It states that there is contradictor information regarding the compounds carcinogenicity. This argument fails to realize that there has been cancer linked to this compound and the risk does exist. Is a lawn free of weeds worth the putting your dog, your child, your spouse or other loved one at an increased cancer risk?
References
[1] Industry Task Force II on 2,4-D Research Data. 1996. Where in the world and the environment are we: A one day status report and briefing on the reregistration of 2,4-D. Seminar sponsored by the Northwest Food & Forest Education Foundation. Portland, OR, July 31.
[2] Hess, F.D. 1993. Herbicide effects on plant structure, physiology and biochemistry. In Pesticide interactions in crop production: Beneficial and deleterious effects, ed. Altman, J. Boca Raton: CRC Press.
[3] Littorin, M “Dioxins in Blood from Swedish Phenoxy Herbicide Workers.” In Lancet Vol.344 (8922), August 27,19994 pp.611-612.
[4] Zychlinkski, L. and S. Zolnierowicz. 1990. Comparison of uncoupling activities of chlorophenoxy herbicides in rat liver mitochondria. Toxicol. Lett. 52:25-34.
[5] Palmeira, C.M, A.J Moreno and V.M.C. Madeira. 1994. Interactions of herbicides 2,4-D and dinoseb with liver mitochondrial bioenergetics. Toxicol. Appl. Pharmacol. 127:50-57.
[6] Littorin, M “Dioxins in Blood from Swedish Phenoxy Herbicide Workers.” In Lancet Vol.344 (8922), August 27,19994 pp.611-612.
[7] Gopher://ecosys.drdr.VirtualLibrary/gen/ toxins/2%2C4-D
[8] Kogevinas, M. “ Soft Tissue Sarcoma and non-Hodgkins Lymponmain Workers exposed to phenoxy-herbicides, chlorophenols, and dioxins – 2 nested case studies.” In Epidemiology. Vol.6 (4) July, 1995. Pp.396-402
[9] Environment Canada Fact Sheet, “Pesticides :2,4-D, MCPA, Dichlorprop, Mecoprop”
[10] Kogevinas, M. “ Soft Tissue Sarcoma and non-Hodgkins Lymponmain Workers exposed to phenoxy-herbicides, chlorophenols, and dioxins – 2 nested case studies.” In Epidemiology. Vol.6 (4) July, 1995. Pp.396-402
[11] Associate committee on Scientific Criteria for Environmental Quality; Subcommittee on Pesticides and Industrial Organic Chemicals. “2,4-D Some Current Issues” NRCC No. 20647. National Research Council of Canada, 1983. Pp. 29,55.
[12] Morrison, H. et al. 1993.Farming and Prostate Cancer Mortality. American Journal of Epidemology 137(30):270-280
[13] Environment Canada Fact Sheet, “Pesticides :2,4-D, MCPA, Dichlorprop, Mecoprop”
[14] Nishioka, M.G. et al. 1999. Distribution of 2,4-dichlorophenoxy acetic acid in floor dust throughout homes following homeowner and commercial lawn applications: Quantitative effects of children, pets and shoes. Environ. Sci. Technol. 33:1359-1365.
[15] Cheah, U-B, R.C. Kirkwood, and K-Y. Lum. 1997. Adsorption, desorption and mobility of four commonly used pesticides in Malaysian agricultural soils. Pesticide Science 50:53-63.
[16] Gopher://ecosys.drdr.VirtualLibrary/gen/ toxins/2%2C4-D
[17] Interdepartmental Executive Committee on Pest Management. “2,4-D Re-evaluation Update and Label Improvement Program.” Note to CAPCO C94-08. November 23, 1994.