Section 13: Pesticides and the Environment Flashcards
List the processes that affect pesticides once they are released into the environment.
Degradation
Bioaccumulation
Biomagnification
Volatilization and vapour drift
Adsportion
Absorption
Spray drift
Surface runoff
Leaching
Soil erosion
Explain what persistence is.
A pesticide with a long half life remains in the environment without a change for a long period of time and is said to be persistent.
Explain each of the following:
Microbial Degradation
Chemical degradation
Photo degradation
Microbial degradation occurs when pesticides are used as an energy source or food by microorganisms.
Chemical degradation involves chemical reactions that occur between pesticide and other chemicals in the environment
Photo degradation is the breakdown of pesticides by sunlight
What is the term that is defined as the process of a pesticide building up in the body tissues of animals?
Bioaccumulation
What factors increase vapour drift?
When high pressures that produce small droplets
When temperatures are high
When relative humidity is low
When volatility pesticide formulations are selected
Describe the difference between adsorption and absorption of pesticides.
Adsorption in soil is the ability of a solid or liquid material to bind onto the surface of soil particles.
Absorption is the ability of a substance to move into organisms or structures.
List 4 factors that affect the adsorption of pesticides onto soil particles.
Characterists of the pesticide
Soil moisture
Soil pH
Soil texture
Define spray drift.
The airborne movement of droplets away from the treatment site during application.
List the factors that can reduce spray drift.
Decrease spray pressure to increase droplet size
Avoid applications when winds will cause significant drift
Avoid applications in inversions or unstable weather conditions
use nozzles that will produce larger droplet sizes
Reduce the speed of the application equipment
Add adjuvents to the spray tank to decrease drift
Select a different formulation that will reduce the possibility of significant drift
When do atmospheric inversion conditions occur?
Inversions occur when the wind is calm and air temperature at the ground level is lower than the air above it
When does the greatest loss of pesticides from the treated area due to surface runoff occur?
When the rain falls within 24 hours of application
List 5 methods of reducing surface runoff of pesticides.
Use an alternative control method
Use adjuvents to make the pesticide adhere to plant surfaces
Incorporate the pesticide into the soil asap
If rain is expected, delay your application of pesticide
Apply conservative applications on highly sloped lands
Avoid the application on barren soils
Define leaching and list 5 actions to reduce the leaching of pesticides.
Leaching is the movement of soluble materials through the soil.
Reduce leaching by:
Using alternatives to pesticide
Use the minimum application rate as the label will allow
Use a pesticide that adsorbs into soil readily and does not leach
Do not irrigate for at least 24 hours after application
Do not apply pesticides in areas of higher water table where soil is saturated with water
Do not apply pesticides within 24 hours of anticipated precipitation.
List 6 ways water can be contaminated by pesticides.
Water can be contaminated by:
Runoff, leaching, movement of soil, direct application, drift, spills
List 4 actions that an exterminator can take to protect beneficial insects from pesticides.
Minimizing pesticide usage
Using alternative pest control practices
Choosing the pesticide least harmful to beneficial insects
Not treating edges of areas where insect predators take shelter
Minimizing drift onto non-target areas
