For the Instructor
These student materials complement the Future of Food Instructor Materials. If you would like your students to have access to the student materials, we suggest you either point them at the Student Version which omits the framing pages with information designed for faculty (and this box). Or you can download these pages in several formats that you can include in your course website or local Learning Managment System. Learn more about using, modifying, and sharing InTeGrate teaching materials.Water Quality Impacts
Runoff from agricultural areas is often not captured in a pipe and discharged into a waterway; rather it reaches streams in a dispersed manner, often via sub-surface pathways, and is referred to as non-point source pollution. In other words, the pollutants do not discharge into a stream or river from a distinct point, such as from a pipe. Agricultural runoff may pick up chemicals or manure that were applied to the crop, carry away exposed soil and the associated organic matter, and leach materials from the soil, such as salts, nutrients or heavy metals like selenium. The application of irrigation water can make some agricultural pollution problems worse. In addition, runoff from animal feeding operations can also contribute to pollution from agricultural activities.
The critical water quality issues linked to agricultural activities include:
- Fertilizers – nutrients (nitrogen and phosphorus)
- Eutrophication – dead zones
- Pesticides
- Soil erosion
- Animal Feeding Operations
- Organic matter
- Nutrients
- Irrigation and return flows
- Salinity
- Selenium
Review the following fact sheet on agricultural impacts on water quality:
Protecting Water Quality from Agricultural Runoff, 2005, EPA Fact Sheet on Agricultural Runoff (Acrobat (PDF) 119kB Jan3 18)
Check Your Understanding
Answer the following questions:
What is nonpoint source pollution?
What agricultural activities contribute to nonpoint source pollution?
What are the major water pollutants contributed by agricultural activities?