Here are 5 reasons why restrictions on non-essential uses of pesticides are so important.
1. Pesticides pose risks to human health.
- Independent, peer-reviewed studies have established that serious health risks are associated with human exposure to chemical pesticides.
- The range of harmful effects includes adverse reproductive, neurological and respiratory outcomes. Researchers have identified increased risks for Parkinson’s disease, asthma and obstructive lung disease, Amyotrophic Lateral Sclerosis (ALS), diabetes, and cancers such as non-Hodgkin lymphoma, leukemia and cutaneous melanoma.
- Exposure can occur through direct contact with skin (dermal absorption), through food and water (oral ingestion), or from breathing (inhalation).
- Those at particular risk include children, pregnant women, people with chronic illnesses, those with chemical sensitivities and, indeed, otherwise healthy adults.
- Pesticide toxicity can be greatly increased when other chemicals are added to the main active ingredient in retail product formulations. These additives may include surfactants, solvents, preservatives or other product enhancers. Formulations can be many times more toxic than the main active ingredient alone.
- See the Resources page of this web site for references to detailed overviews of more than 500 epidemiological studies documenting pesticide health risks.
2. Pesticides used on lawns and green spaces are especially risky for children.
- Children are most at risk because of their relatively large body-surface-area-to-weight ratio, their long life expectancy (for problems to develop), and their direct exposure when in contact with treated lawns when playing on the grass.
- Dangers of exposure for children include increased risks of low birth weight and pre-term births in babies, reduced head circumference at birth, deficits in cognitive and motor development, hormonal (endocrine) disruption, neural tube defects, birth defects such as cleft palate, learning disabilities and other developmental deficits such as autism, and childhood cancers such as leukemia and brain cancer.
- In many studies, the harmful effects noted in children were related to the exposure of their mothers during pregnancy or to children’s exposure at a young age.
- For some harms affecting children, there are critical windows of vulnerability — i.e. pre-conceptual, prenatal or during childhood.
3. Cosmetic pesticides contaminate our water.
- A number of pesticides are highly toxic in water, where they harm fish and aquatic insects.
- Some pesticide contamination of rivers, lakes and streams occurs as a result of drainage from agricultural land. But run-off from urban use of pesticides on residential lawns, city parks and golf courses is also a significant source.
- Pesticides that move through soil also contaminate groundwater sources that people rely on for drinking water.
4. Pesticides are risky for pets.
- Dogs and cats that play on treated green spaces are directly exposed to pesticides.
- As the Winnipeg Humane Society notes, pets that go outdoors often lie on lawns, chew grass and other plants, lick their paws and groom themselves. These behaviours increase their risks of inhaling and ingesting pesticides.
- Animal physiology is not exactly the same as human physiology, but researchers note that humans and dogs, for example, share about 360 similar diseases with correspondingly similar genetic factors.
- Not surprisingly, then, animals experience increased risk of illness and disease from exposure to pesticides, just as people do.
- In some cases, the risks for animals are greater. For example, a study published in a veterinary journal in 2014 describes how cats lack enzymes that detoxify certain kinds of ingested chemicals in the liver.
5. Pesticides harm pollinating insects that we depend on for garden vegetables and food crops.
- Pollinators, which play a critical role in plant reproduction, are vulnerable to adverse health and behavioural impacts caused by exposure to pesticides.
- Food sources for foraging bees and other pollinators are reduced when herbicides are applied to lawns and green spaces, removing flowering plants that provide nectar.
- Pollinators ingest residue pesticides when gathering nectar from plants that have been treated. In the case of bees, they then carry this contaminated food back to the hive, where others are exposed.
- A study published in the Journal of Experimental Biology in 2015 found that exposure to low concentrations of glyphosate (a common chemical herbicide) interfered with bees’ ability to navigate back to their hives.
- Much more research is needed on the sub-lethal effects of herbicides on pollinating insects. Given multiple environmental stresses on bee populations, the authors of a 2019 systematic review of published research urge a precautionary approach to pesticide regulation while further studies are carried out to assess the risks to vital pollinators.
MORE INFORMATION: See our Resources page for links to systematic reviews of peer-reviewed epidemiological studies of human health risks associated with pesticides.