Unit 4 Pesticides in the Environment


  • Sources of Contamination
  • Sensitive Areas
  • Pesticide Movement
  • Harmful Effects on Nontarget Plants and Animals
  • Harmful Effects on Surfaces

Learning Objectives Unit 4 Pesticides in the Environment

After you complete your study of this unit, you should be able to:

  • Distinguish between point-sources and non-point-sources of environmental contamination by pesticides.
  • List factors you should consider when you accidentally or intentionally release a pesticide into the environment.
  • Explain why sensitive areas are important considerations for pesticide handlers.
  • Name the routes by which pesticides can move offsite into the environment.
  • Describe factors that influence whether pesticides will move offsite in the air.
  • Describe factors that influence whether pesticides will move offsite in water.
  • Describe ways that pesticides move offsite in or on objects, plants, or animals.
  • Recognize that nontarget plants and animals can be harmed by both pesticides and pesticide residues.
  • Describe harmful effects that pesticides can have on surfaces.

Test Your Knowledge Unit4 Pesticides in the Environment

Q. What is the "environment"?
A. Environment is everything that surrounds us - indoors and outdoors - including natural elements, manmade objects, people, and other living organisms.

Q. Explain what is meant by point-source and non-point-source contamination of the environment by pesticides, and give an example of each.
A. Point-source pollution comes from a specific, identifiable place (point). A pesticide spill that moves into a storm sewer is an example of point-source pollution. Non-point-source pollution comes from a wide area. The movement of pesticides into streams after broadcast applications is an example of non-point-source pollution.

Q. Name some ways that careless pesticide handling could lead to point-source pollution.
A. Examples of ways that careless pesticide handling could cause point-source pollution include:

  1. Mismanagement of wash water and spills produced at equipment cleanup sites.
  2. Improper disposal of containers, water from rinsing containers, and excess pesticides.
  3. Failure to correctly clean up leaks and spills at pesticide storage sites.
  4. Spilling pesticides while mixing concentrates or loading pesticides into application equipment.

Q. What environmental factors should you consider any time you accidentally or intentionally release a pesticide into an environment?
A. Consider:

  1. Whether there are sensitive areas in the environment at the pesticide use site that might be harmed by contact with the pesticide,
  2. Whether there are sensitive offsite areas near the use site that might harmed by contact with the pesticide,
  3. Whether there are conditions in the immediate environment that might cause the pesticide to move offsite, and
  4. Whether you can change any factors in your application or in the pesticide use site to reduce the risk of environmental contamination.

Q. What is a "sensitive area? Give four examples of sensitive areas that you must be especially careful to protect when you are handling pesticides.
A. Sensitive areas are sites or living things in environments that are easily injured by a pesticide. Four examples of sensitive areas are:

  1. Places where pesticides might get into ground water or surface water; homes, schools, playgrounds, hospitals, and other places where people are present;
  2. Places where there are animals - endangered species, bees, other wildlife, livestock, or pets;
  3. Places where crops, ornamental plants, or other sensitive plants are growing; and
  4. Areas where food or feed is processed, stored, or served.

Q. List three routes by which pesticides can move offsite.
A. The three routes are:

  1. In air, through wind or through air currents generated by ventilation systems.
  2. In water, through runoff or leaching.
  3. On or in objects, plants, or animals (including humans) that move or are moved offsite.

Q. What factors influence whether a pesticide will move offsite in the air?
A. Factors influencing offsite movement of pesticides are:

  1. Droplet or particle size.
  2. Height and direction of release.
  3. Whether the pesticide tends to form vapors.

Q. Q. Name two cirumstances that might cause a pesticide to move offsite in water.
A. Two circumstances that might cause offsite movement of pesticides in water are:

  1. Too much liquid pesticide is applied, leaked, or spilled onto a surface.
  2. Too much rainwater, irrigation water, or wash water gets onto a surface that contains pesticide residue.

Q. Give some examples of ways that pesticides can move offsite on or in objects, plants, or animals.
A. Some examples of ways pesticides can move ofsite by way of objects, plants or animals are:

  1. Pesticides may be carried offsite if they stick to such things as shoes or clothing, animal fur, or blowing dust - anything that moves from the use site to another location.
  2. Pesticide residues may remain on treated surfaces, such as food or feed products, when they are taken from the use site to be sold.

Q. In addition to direct contact with the pesticide during application or through drift or runoff, how else may nontarget plants and animals be harmed by a pesticide?
A. Nontarget plants and animals may be harmed by the pesticide residues that stay in the environment for a period of time after the release. These can be residues that remain in soil or on surfaces, or they may be residues that build up in the bodies of animals, harming those animals themselves and sometimes other animals that feed on them.

Q. What kinds of damage can some pesticides cause to surfaces?
A. Surfaces may become discolored, be pitted or marked, be corroded or obstructed, or be left with a visible deposit.

Additional Resources
Clemson University websites:

  1. Regulatory Services Clemson University Department of Pesticide Regulation
  2. Extension Pesticide Information Program