Food and the Future Environment

Water Quality Impacts


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

Check Your Understanding

Review the following fact sheet on agricultural impacts on water quality:

Protecting Water Quality from Agricultural Runoff, 2005, EPA Fact Sheet on Agricultural Runoff