We are exposed to pesticides every day. According to the Centres for Disease Control and Prevention, pesticides are in our food, lawn and garden applications, and insecticides at home. Some people (especially farmers and pest control applicators) are also exposed at work.
In Alberta alone, 75 million kilograms of pesticides are sold every year. Farmers use them to remove pests that would otherwise damage crops. Protecting crops allows us to consume a wider selection of healthy foods. It also keeps the prices of food and clothing low. At home, pesticides are used to kill insects that can spread disease or cause structural damage to homes. Gardeners use pesticides to protect their flowers and plants. Pesticides can be used in recreational water to prevent the spread of diseases that are carried in the water. Our society benefits greatly from the use of pesticides.
Scientific studies suggest that pesticides may be associated with some medical conditions in children and adults. In children, high exposure to pesticides has been linked with developmental problems and many types of cancers.
Similarly, significant pesticide exposure during pregnancy has been linked to birth defects and death of the baby before birth. In adults, high amounts of pesticide exposure have been associated with conditions of the nervous system, cancers, and poor fertility.
However, these studies show very weak associations and mixed results. They are usually of poor quality. ‘Association’ only means that two events occur together. It does not prove that pesticides cause these medical conditions. Often it is not possible to draw a firm conclusion about health effects from association studies. We can only speculate that pesticides may affect human health.
We do know that harmful health effects strongly depend on:
If used properly, pesticides are unlikely to cause health problems.
If science is unclear about whether pesticides should be used, how do you decide whether to use them? Consider several factors, including regulation, proper use, exposure of children and pregnant women, prevention of pest problems, and your comfort level with pesticide use.
As there are risks associated with pesticide use, these products are tightly regulated in Canada. The Pest Management Regulatory Agency of Health Canada reviews the effectiveness and safety of pesticides. Scientific studies must show that the product serves a useful purpose, and does not pose unacceptable health or environmental risk. Only then will the product be allowed for sale and use in Canada. Provincial, territorial, or municipal governments may further restrict the use of pesticides based on local concerns.
If new scientific evidence shows that a registered product is more harmful than helpful, it can be withdrawn from use. For example, DDT (dichlorodiphenyltrichloroethane) was widely used as an agricultural insecticide from the 1940s to the 1960s. It was later found to be harmful to human health and the environment, and banned in the mid-1980s.
Regulation of pesticides is an important way to minimize potential health risks. Only use approved pesticide products allowed for use in your city or town.
Pesticide products must include instructions on how to use the product safely. The instructions may include the amount required, how often, and any protection that is to be used. For instance, protective gloves, masks, and clothing may be required. It is also advised that warning signs be posted where a pesticide is applied, so that people can avoid exposure. Following these instructions should greatly reduce the chance of harmful exposure and minimize the risk of poor health effects associated with pesticides. Health Canada provides more details on the safe use of pesticides (see links in sidebar).
Studies have shown that children and unborn babies may be at higher risk if exposed to pesticides and other chemicals. Since chemicals can sometimes interfere with normal growth and development, they can cause birth defects, childhood cancers, and in severe cases, death. Children, pregnant and breastfeeding women may be more sensitive to pesticides. For this reason, they should stay away from them as much as possible. Store any pesticides in the home out of children’s reach. When applying pesticides, check how long children and pregnant women should avoid the area. A different formulation of the same pesticide can stay in the environment for varying lengths of time. For instance, some preparations of the lawn herbicide 2,4-D can stay in the environment for weeks to months.
Before considering pesticides, take steps to discourage pests in your surroundings by applying the principles of integrated pest management. This approach emphasizes prevention and control of pests, as well as the responsible use of pesticides. For instance, a healthy lawn that is maintained well is less likely to have pest problems. Thick grass smothers weeds and prevents germination of their seeds. If a pest is found in the lawn, first identify the type of pest. Next, take steps to control that specific pest. [Health Canada provides more details on integrated pest management (see links in sidebar).]
Simple measures in the home can also prevent pest problems. Cockroaches, spiders, and ants are often attracted to food, so keep the house clean and tidy. Similarly, mosquitoes like to be around water. Draining collected water is a necessary part of controlling mosquitoes. Sometimes, a pest suggests an environmental problem in the house. For instance, excess moisture can attract insects like centipedes, millipedes, and spiders, especially in basements. Similarly, carpenter ants can signal a moisture problem and decaying wood. In such cases, remove the cause before trying to remove the pest with chemicals.
Physical barriers can block flies, mosquitoes and rodents from entering the house. Properly fitting screens, weather stripping, and sealing gaps in windows, doors, and house foundations can all make a difference.
From It’s Your Health,
Healthy lawns and integrated
In spite of preventive measures, you may find that pests are an ongoing problem. Pesticides offer a solution. However, the decision to use pesticide may not be easy, given the potential health risks associated with their use. Scientific studies are not very helpful. They suggest that some harm could occur with high exposure levels and in sensitive populations. However, the evidence is not very strong. If instructions are followed, exposure to the pesticide should be very minimal. If a risk truly exists, it is extremely small when the pesticide is used as directed along with proper protection. Base your decision on the potential benefits and risks, as well as your personal preferences. Some families may feel comfortable using pesticides because they follow instructions and protect sensitive people. Other families may not like to take any risk, regardless of how small and uncertain it may be. They may choose to not use pesticides at all.
Pesticides play an important role in protecting our crops, homes, and water from unwanted pests. There is a small chance that pesticides can cause harm to human health. Keep in mind that harm is unlikely when an approved product is used as directed on the label and recommended precautions are taken. Children and women who are pregnant or breastfeeding are considered especially sensitive. They should not be exposed to chemical pesticides. Remember, the best measure is to prevent the pest problem before using pesticides.