Pesticide assessments in Canada: Environmental risk
On this page
- Purpose of an environmental risk assessment
- Understanding ecotoxicity, environmental fate and behaviour
- Conducting an environmental risk assessment
Purpose of an environmental risk assessment
The purpose of an environmental risk assessment is to study if pesticide exposure could cause negative effects to plants, animals, and the environment. Negative effects can include mortality, reduced growth, impaired reproduction, and other related measures.
Understanding ecotoxicity, environmental fate and behaviour
An environmental assessment considers:
- ecotoxicity: potential for a pesticide to cause negative effects on plants, animals, and the environment
- environmental fate and behaviour: what happens to a pesticide after it enters the environment, including how it moves, transforms, and interacts in the environment
For more information about ecotoxicity and environmental fate:
Conducting an environmental risk assessment
PMRA scientists use a scientific risk assessment process to protect the environment. The process is accepted by scientists and organizations across the world.
Exposure assessment (environmental fate and behaviour)
The exposure assessment considers what happens to a pesticide once it enters the environment. It studies how a pesticide may spread from the site where it's applied to other areas. Pesticides can spread through soil, water, and air.
The assessment also checks the potential intake and build-up of pesticides in plants and animals.
To determine what happens when a pesticide is in the environment, the exposure assessment considers:
- how the pesticide is used (from the value assessment)
- the pesticide's physical and chemical properties (from the chemistry assessment)
- findings from laboratory studies
- field studies that show what happens to the pesticide in different Canadian environments on land and in water
- monitoring data such as information from the national-scale water monitoring program for pesticides
Effects assessment (environmental toxicology)
The effect assessment looks at the negative effects a pesticide could have on a wide range of plants and animals that aren't the target of the pesticide (non-target organisms). This includes effects on biodiversity and the food chain.
We use laboratory and field studies to evaluate potential effects of pesticides on organisms like plants and animals.
We consider these organisms on land:
- earthworms and other invertebrates that live in soil
- pollinators such as bees
- beneficial arthropods such as predatory and parasitic insects, spiders and mites
- birds
- small wild mammals
- plants
We consider these organisms in water:
- aquatic invertebrates
- fish
- amphibians such as frogs
- algae
- aquatic plants
The assessment examines the relationship between different amounts of pesticide exposure and the effects on organisms that aren't the target of the pesticide (non-target organisms). It considers lethal (mortality) effects and sub-lethal effects including reduced growth, impaired reproduction, and other related measures.
Risk characterization
A risk characterization takes the information from the exposure and effects assessments. We use the information to describe the overall risk from a pesticide, including the likelihood and severity of environmental effects. We use the risk characterization to decide whether the pesticide can be used in Canada safely.
More information
For more information on environmental risk assessments, visit: