Chapter 11 Flashcards
Distinguish between point source and non point source pollution? What is an example of each?
Point source contamination comes from a specific identifiable place of location ( pesticide spill entering a storm sewer)
Non point source comes from a widespread area. (movement of pesticide into streams following a broadcast application)
How do site characteristic affect the chance of runoff and risk of contamination of surface water?
Slope - steeper slopes present a greater risk of runoff
Vegetative Cover - vegetation helps trap or slow down moving water
Soil Characteristics - water soaks into finer textured (clay) soils more slowly. Finer soils have more runoff
Temperature - if the ground is frozen water cannot infiltrate and runoff will be more likely
Rainfall and irrigation - heavy rain will contribute greatly to runoff
Groundwater
water that is underground in cracks in the bedrock and in the spaces between gravel and rocks. It is the sources of water for wells and springs
Water Table
boundary between the saturated zone (all space is filled with water) and overlying unsaturated rock and soil (pores filled with air)
Aquifer
Overall geologic formation from which groundwater can be drawn
How do pesticides get into groundwater?
groundwater is recharged by water that filters down through the unsaturated zone to the water tables. The water that moves downward can carry pesticides via leeching
How do pesticides characteristics affect the rate of leaching and risk of groundwater contamination?
High solubility - pesticides leach by moving in soil water
Persistence - it takes time for a pesticide to reach groundwater.
Low adsorption - a pesticide bound strongly to soil particles with not be free to move in soil water
Where on a pesticide label can you find information about surface water and groundwater protection?
Follow the use direction. specific warning in the precautionary statement
What steps can you take to minimize the risk of pesticide contamination of groundwater and surface water?
Follow Best Management Practices - effective commonsense practices that emphasize the proper mixing, loading, application, and disposal of pesticides
Use IPM
Identity Vulnerable areas and avoid pesticide application
Keep pesticides away from wells
select appropriate mix and load sites
use containment pads for mixing and loading
avoid back siphoning
avoid overflow
improve land use and application methods
watch weather conditions
select products wisely
handle pesticides safely
What is the purpose and features of a containment pad for mixing and loading pesticides?
Designed to contain spills, leaks, overflows, and waste water for reuse by the applicator or for disposal
must be made of an impermeable material. must be concave or have curbs or walls, must be equipped with a system for removing and recovering materials
What is back siphoning of pesticides into a water supply
reverse flow of liquid into a fill hose
How does back siphoning occur??
suction occurs at the end of a fill hose when you turn off the water there is a drop in water pressure. If the end of the hose is in the spray mix the suction could cause pesticide mix to back siphon into your water sources
Why is back siphoning a problem?
Can contaminate the water source you are drawing from
What are 3 ways to prevent back siphoning?
Use a water tank
maintain an air gap
install back flow prevention between the hose or pipe end and the water source
What label restriction intend to minimize the risk of surface water and groundwater contamination
do not apply directly to water or to areas where surface water is present
do not contaminate water supplies while cleaning equipment or disposing of equipment wash water
may prohibit you from mixing/applying with a certain distance of well or surface water
groundwater warning statement if applicable
