Description
Pesticides are substances that are used to control organisms considered undesirable or harmful. They are generally classified into broad categories depending on what they are used for:
- Insecticides (harmful insect control)
- Rodenticides (rodent control)
- Herbicides (weed control)
- Fungicides (control of plant disease caused by fungi), etc
Pesticides are used mainly in the following sectors:
- In agriculture, to protect animal and plant production
- In pest control (extermination), to control harmful organisms inside or outside buildings, for example:
- Wasp nests
- Rodents
- Cockroaches
- Bed bugs
- In ornamental horticulture and landscape maintenance, to protect trees, shrubs, flowers, lawns, etc
Pesticides can also be useful in the public health sector. They are used, for example, to control mosquitoes that spread West Nile Virus (WNV) or ticks passing on Lyme disease.
Pesticides have toxic effects on living organisms. If they are highly toxic, these products can involve certain risks for health and the environment. They are, however, generally considered safe if they are used judiciously and in accordance with the manufacturer’s instructions.
For more details about what pesticides are made of and what they are used for, go to the All about pesticides page.
Risk of exposure to pesticides
Exposure to pesticides can affect human health. Pesticides can enter the body or come into contact with human tissues in various ways.
Exposure via the skin
Pesticides can be absorbed through the skin, for example, if a person handles products without protection or if they touch surfaces contaminated by pesticides.
In sufficient amounts, pesticides can cause health problems. They affect the skin and eyes in particular.
Some parts of the body absorb pesticides more easily, such as:
- The scalp
- The forehead
- The eyes
- Mucous membranes, such as in the mouth and nose
Exposure via the respiratory system
Pesticides applied as an aerosol or gas can easily enter the body through the respiratory system. This route of exposure to pesticides causes the most direct and most rapid poisoning.
Make sure that any areas you are treating with pesticides are well ventilated. If necessary, leave the area temporarily. Follow the directions on the product label.
Exposure via the mouth
Pesticides can be absorbed by mouth. This often happens when a person eats a food contaminated by pesticides or if they put their hands to their mouth after handling pesticides.
A number of common habits lead to this type of contact with pesticides, even accidentally. Therefore, you should avoid:
- Smoking, drinking or eating when you handle or use pesticides
- Storing pesticides in an inappropriate or incorrectly identified container, such as a fruit juice bottle
- Storing pesticides in a place that children can access easily, for example, under the kitchen sink
Food
Food is often the main source of exposure to pesticides. In particular, fresh fruits and vegetables sometimes contain traces of pesticides. These amounts are, however, very low and are generally compliant with the standards established by Health Canada for acceptable concentrations of pesticides in food, called “maximum residue limits”.
According to the 2013-2014 Report of the Canadian Food Inspection Agency 
(CFIA), foods of plant and animal origin were tested for pesticide residues; the compliance rate with maximum residue limits established by Health Canada was 98.27%.
Furthermore, the CFIA’s 2013-2014 Children’s Food Project , which included baby foods, showed that the compliance rate of these foods with maximum residue limits for all concentrations of pesticide residues was 100%.
Following the 2007-2011 monitoring program conducted by the Ministère de l’Agriculture, des Pêcheries et de l’Alimentation du Québec (MAPAQ), similar conclusions were drawn regarding fresh fruits and vegetables in Québec. To find out more, consult the publication Résidus des pesticides dans les fruits et légumes frais vendus au Québec 2007-2011 (in French only).
Eating fruits and vegetables is essential to health. The benefits of these foods greatly outweigh the potential risks associated with the low amounts of pesticide residues they might contain. Concerns about pesticide use should not mean that you eat fewer fruits or vegetables.
You can, however, develop the habit of washing fruits and vegetables thoroughly before eating them to reduce the amount of pesticides that might be on the surface. Make sure that you eat a wide variety of fruits and vegetables too, since the amount of the different pesticides that may be in these foods varies widely. These simple precautions will reduce your exposure to some pesticides while increasing the variety of fruits and vegetables that you eat.
Drinking water
Drinking water may also be a potential source of exposure to pesticides. However, the water distributed by municipal systems usually complies with the pesticide standards in the Ministère de l’Environnement et de la Lutte contre les changements climatiques (MELCC)’s Regulation respecting the quality of drinking water . Furthermore, according to the Pesticides Management Code , pesticides must be applied a certain distance from bodies of water, watercourses and water intakes. This measure is crucial, especially in agriculture, for it helps protect surface wells, artesian wells and groundwater.
To find out more, go to the MELCC’s page La présence de pesticides dans l’eau en milieu agricole au Québec (in French only).
Acute poisoning
In general, acute poisoning occurs immediately or shortly after a single episode of exposure or short-term exposure to a pesticide. Acute poisoning could, for example, occur in young children who have access to improperly stored pesticides. Similarly, adults could be poisoned if they handled pesticides without taking all the necessary precautions. The severity of acute poisoning can vary depending on:
- The toxicity of the pesticide
- The amount and concentration of the active ingredient in the product
- The exposure route
Signs or symptoms of acute poisoning
The most common signs or symptoms of acute pesticide poisoning are as follows:
- Headaches
- Nausea
- Vomiting
- Dizziness
- Fatigue
- Loss of appetite
- Eye or skin irritation at the site of contact with the product
Chronic poisoning
A person may also have chronic toxic effects after being in contact with low doses of pesticides for days, months or years. The person is then a victim of chronic poisoning.
Signs or symptoms of chronic poisoning
The main signs or symptoms that indicate chronic poisoning are as follows:
- Fatigue
- Frequent headaches
- Loss of appetite
- Weight loss
Other risks of long-term toxic effects
The World Health Organization and an affiliate, the International Agency for Research on Cancer, have classified some pesticides as “probably” or “possibly” carcinogenic. Health Canada is therefore re-evaluating these pesticides to determine if their current conditions of use in Canada pose a threat. The results of this re-evaluation might lead to restrictions on the use of these pesticides or cause them to be taken off the market.
Studies are also being conducted on the potential long-term effects of the use of some pesticides. These risks are related to:
- Reproduction
- Fetal development, especially the nervous system
- Hormone balance
- Immune system
If the studies confirm these risks, Health Canada will also revise the registration of the pesticides concerned.
Treatment
If you think that you have been a victim of accidental pesticide poisoning, call the Centre antipoison du Québec immediately at 1-800-463-5060.
The nurse at the Centre antipoison might advise you to go to the emergency room immediately. If so, she will notify the emergency room staff that you are on your way. Don’t forget to bring the label of the pesticide involved with you. This will allow the medical staff to make a diagnosis quickly and decide which treatment is appropriate in your case.
You will find information about first aid for someone who has been poisoned by pesticides on the Centre antipoison du Québec site (in French only).
People at risk
The toxic effects of pesticides can affect anyone. Children and pregnant women are, however, particularly vulnerable to these effects.
Children are more vulnerable to pesticides than adults for a number of reasons:
- Children’s skin surface area relative to body weight is higher than in adults
- Children absorb some pesticides more easily through their skin than adults
- Children are less able to deal with the toxic effect of pesticides because their metabolism has not reached maturity
- Babies and young children spend more time on the ground, where pesticides are applied and build up
- Children can easily come into contact with objects contaminated by pesticides
Exposure to certain pesticides during pregnancy can adversely affect a child’s development in the short or medium term. Pregnant women should therefore avoid exposure to or handling pesticides.
Protection and prevention
Pesticides should be used only as a last resort, with precautions and in a responsible manner.
Pesticides are sometimes necessary, such as for a cockroach, bed bug or rodent infestation. In this type of situation, you should hire a certified pest control specialist who has a permit and a certificate issued by the Ministère de l’Environnement et de la Lutte contre les changements climatiques (MELCC). Carefully follow the pest control specialist’s instructions on how to prepare the area prior to treatment. Follow the instructions that he gives you during the treatment and for the period after treatment too. Each step is essential to ensure the treatment is effective and to protect your health.
To find out how to choose a certified pest control specialist, go to the Comment choisir une entreprise de gestion parasitaire? page on the MELCC’s website (in French only).
Plan d’agriculture durable 2020-2030
The Plan d’agriculture durable 2020-2030 plans to accelerate, by 2030, the adoption of best agri-environmental practices. In particular, it aims to reduce the use of pesticides and the health and environmental risks associated with them. To find out more, see the Utilisation et gestion des pesticides page (in French only).
Regulation of the marketing and use of pesticides
The Government of Canada, the Government of Québec and some municipalities regulate pesticides.
Pesticide registration
To be imported, sold or used in Canada, a pesticide must first be registered, that is, approved in accordance with the Pest Control Products Act. Health Canada’s Pest Management Regulatory Agency (PMRA)administers this Act.
PMRA evaluates every pesticide to ensure compliance with the most stringent health, safety and environmental protection requirements. It must also ensure that:
- The pesticide is effective
- The pesticide label provides directions for safe use
- The pesticide residues that may be found on or in food products are not harmful to consumer health
Framework for the sale and use of pesticides
The sale and use of pesticides are governed by laws and regulations that are intended to protect health and the environment. The application of these provisions ensures that:
- Only the least toxic and safest pesticides are readily available to the general public
- The most toxic pesticides are restricted to professional and specialized use
In Québec
In Québec, pesticide use is regulated by the MELCC pursuant to the Pesticides Act. The MELCC developed the Pesticides Management Code to regulate the sale and use of pesticides. The Code’s provisions are intended to better protect the environment and health, especially children’s health. To find out more, go to the Pesticides section.
Municipal regulation of pesticide use
Since the early ’90s, many municipalities in Québec have regulated pesticide use on their territory. These municipalities must ensure that their regulatory provisions comply with the MELCC’s Pesticides Management Code. Consult the liste des municipalités du Québec qui réglementent en matière de pesticides (in French only).
Useful sites
- All about pesticides
Ministère de l’Environnement et de la Lutte contre les changements climatiques - Pesticides and food safety
Health Canada - Résidus de pesticides dans les fruits et légumes frais vendus au Québec 2018-2019
Ministère de l’Agriculture, des Pêcheries et de l’Alimentation (in French only)
Last update: February 14, 2022
