Caring for and Healing the Earth

Pesticides, Poisons and Health Issues

Pesticide Fact Sheet

Alternative to Pesticides Team (Kitchener-Waterloo, Ontario)


What are pesticides?

A pesticide is any substance, or mixture of substances used to kill, control or prevent an unwanted species of life. It includes herbicides ("weed" killers), insecticides and fungicides, etc. Pesticides are unique in that they are produced and released into the environment for their toxic effects. In Canada, herbicides such as 2,4-D are the pesticides most commonly used. Many products used to kill "weeds" and at the same time fertilize, will contain 2, 4-D. Even when used as directed, pesticides have many negative side effects on human health and the environment.


They are legal, but are they safe?

Many people believe that making a product legally available is a guarantee of safety, but we only have to look at the history of cigarettes to know that consumer safety is not always allowed to interfere with commerce."1  According to Environment Canada, "Pesticides are poisons, otherwise they wouldn't work."2 All pesticides in Canada are government registered but this may not mean that they are safe. In some instances, federal registration of pesticides in Canada was subsequently found to have been based on invalid or unreliably produced data. Pesticide formulations may contain as little as 2% of the "active" ingredient. The rest is made up of so-called "inert" ingredients (or formulants), such as solvents and emulsifiers. Inerts may themselves be hazardous substances - for instance, benzene or formaldehyde, or some combination of a possible 3,000 other chemicals. Exact formulas are protected from public scrutiny, because they are considered to be trade secrets.3 Pesticides are not tested in combination - the synergistic effects may amplify their toxicity as much as 1000 times. No studies have been published attesting to the safety of pesticides. Pesticides are designed to kill.


So, What are the Dangers?

Children, fetuses, and the elderly are at greater risk:
Pesticides affect every organ of the body causing many health problems. Studies confim1 that the use of pesticides around the home increases the likelihood of childhood leukemia, brain cancer, behavioural problems, environmental sensitivities, attention deficit disorder, cerebral palsy, mental problems, suppressed immune system functions, etc. Children whose parents use garden pesticides have a seven times higher risk of developing childhood leukemia. Children are more likely to suffer greater effects from pesticide exposure because of their immature immune systems. The elderly, people with impaired immune systems, allergies &/or asthma are also all at risk of developing health problems from pesticide exposure i.e. airway passages narrowing causing breathing difficulties for asthmatics.

Hormone Disruption:
Some pesticides, including 2,4-D, can act as hom1one disruptors. Scientists are now focusing on pesticides belonging to a group of chemicals known as endocrine disruptors which have been linked to reproductive problems in wildlife. Some researchers believe that endocrine disruptors may be causing higher rates of breast cancer, lower spem1 counts, reduced intelligence and behavioural changes in children,4 and penile defects in newborn males.

The Journal of National Cancer Institute, 1990 reports that a study of 70,000 Saskatchewan farmers show a significant positive association between non-Hodgkin's lymphoma and the number of acres sprayed with herbicides, predominantly 2,4-D. According to the U.S. Environmental Protection Agency, 95% of the pesticides used on residential lawns are considered to be possible or probable carcinogens.5

Other Health Effects in Humans:
Acute: The Canadian Centre for Occupational Health and Safety identifies some as: nausea or vomiting, eye, skin, respiratory and throat irritation, muscle spasms, and death.
Chronic: - repeated exposures are linked to: neurological problems, brain and lung cancer, immune suppression (i.e. environmental hypersensitivity), leukemia, Parkinson's and Lou Gehrig's disease, kidney damage, non-Hodgkin's lymphoma, & reproductive disorders including endocrine disruption, low sperm counts, and sterility.6


What is the danger to the environment?

Water contamination:
Protecting our drinking water is another good reason to avoid using pesticides. Both groundwater and surface water can be contaminated by chemical use both inside and outside the home. Agriculture Canada reports that between 1981 and 1984 the herbicide atrazine was found at the mouth of the Grand River over 90% of the time, and 2,4-D was found up to 32% of the time7. An Environment Canada study has found that the urban use of pesticides is making an appreciable contribution to pollution in the Great Lakes.8 Many pesticides do not biodegrade and disappear. They persist in the environment, in oceans and rivers, becoming more concentrated as they go up the food chain. Deformities and serious health problems are appearing in beluga whales, alligators and various water birds.

Cancer and Deformities in Animals:
Many pesticides are considered to be carcinogenic (cancercausing). Recent reports from Minnesota are revealing serious deformities (missing eyes & limbs, limbs in the wrong places) in a large percentage of a frog population some as high as 69%. A relationship has been established between these deformities and the use of pesticides.9 Farm animals and pets are also at risk. One recent study showed a significant association between cancer in dogs (canine malignant lymphoma) and owner's use of the herbicide 2,4D.10

Soil Breakdown:
Beneficial organisms (worms, fungi, bacteria, etc.) are destroyed by pesticides, causing a degradation and imbalance in the health of the soil system which may cause infertility, pest outbreaks and soil sterilization.11 Worldwide, the loss of fertile top soil needed to grow crops is a serious threat to future food production.

Pesticide Drift:
"Frequently a portion of the spray fails to reach the target pest or area and deposits on adjacent properties where it can cause damage to animals (including humans) and/or plants."12  A recent study has shown that lawn herbicides have been detected 48 feet away from the designated spray area. There was enough drifted spray to be tracked onto indoor carpeting to contaminate carpets for a year or more.13  Radioactively traced pesticides sprayed aerially over England were discovered 7 days later in Texas.


How am I exposed to pesticides?

The smell of pesticides is often unpleasant, unhealthy to breathe, and offensive to neighbours. Common sense tells us that if you can smell it, you're absorbing it. Pesticides are absorbed through the skin, or by breathing or swallowing them. Pesticides banned, restricted or never registered in North America are sold abroad and used on food crops which we then import, buy, and in turn eat.14  Immediate effects that have been reported include: the acute effects listed above as well as: headaches, allergic-type responses, mental or emotional effects, weakness, nervous system disorders, heart palpitations, fever, miscarriage, swollen glands and anaphylactic shock.15  Many ingested pesticides are stored in the fat tissue and are released gradually into the blood stream over a few years, contributing to autoimmune and degenerative diseases.16 


Did You Know.....

  • Annually billions of kilograms of pesticides are manufactured globally, and over a million kilograms are applied commercially in Ontario alone, mostly in urban centres.17
  • The World Health Organization (WHO) estimates that pesticides affect more than 500,000 people every year, with one in 10 cases resulting in death or permanent disability.
  • 2,4-D, a common herbicide used on lawns today, was an ingredient in Agent Orange used in the Vietnam War. Serious health problems in children of Vietnam War Veterans have been documented.
  • Pesticides are the second most common cause of poisoning in young children.18



1 Moore, Steven. (1994). Poisons on your lawn. Healthy Naturally, 11 (Aug/Sept.), p. 22.
2 Environment Canada. (1987). Fact Sheet Alternatives to Pesticides in Yards and Gardens.
3 Pesticide Action Group. (1 995). "E" Regulatory Anomalies. The problem with pesticides.
4 Johnson, Sharlene K. Pesticides: What you don't know can hurt you. Ladies Home Journal June 1997.
5 Wisconsin's Environmental Decade Institute. (1996). Great Lakes, Great Lawns.
6 Environment Canada. (1989). Pesticides, the right amount.
7 Agriculture and Agri-Food Canada/Ontario Ministry of Agriculture Food and Rural Affairs. (1996). Best management practices: Integrated pest management. p.2.
8 Environment Canada. (1991). Environmental Concentrations of Urban Pesticides.
9 Toronto Star, October 5, 1996 & May 24, 1997
10 Hayes, H.M. et al. (1991 ). Case-control study of canine malignant lymphoma: Positive association with dog owner's use of 2,4-D herbicides. Journal of the National Cancer Institute.83 (17), 1226 1231.
11 Urban Pesticide Caucus. ( 1991 ). Regulating the urban cosmetic use of synthetic pesticides: An action plan for the Province of Ontario. p.17. (Available from the Toronto Environmental Alliance Tel. (416) 348-0660.
12 Ministry of Agriculture and Food. ( 1988). Reducing Pesticide Drift and Crop Damage (October Fact Sheet).
13 Nishioka, Marcia et al. (Battalle Memorial Institute/U.S. E.P.A.). 1996. Measuring transport of lawn applied herbicide acids from turf to home: Correlation of dislodgeable 2,4-D turf residues with carpet dust and carpet surface residues. . Environmental Science and Technologv 30, ( 11) 3313 - 3320.
14 Friends of the Earth. (1989). How to Get Your Lawn and Garden Off Drugs. (Available by calling (613) 230-3352).
15 Pesticide Exposure Group of Sufferers, Pesticide Action Group of Cambridge, 1996. (A vailable from P AG - see "Resources" page for phone numbers).
16 Alive #175 May 1997. The Plague of Pesticides. p. 16
17 Ontario Ministry of Agriculture & Food. Pesticide Use Survev. (1993).
18 Dr. H. Needleman (1994) Raising Children Toxic Free


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