What impact does agricultural runoff have on water sources?

Agricultural runoff significantly impacts water sources primarily by introducing pesticides, fertilizers, and sediment into the water. This runoff occurs when rainwater or irrigation water flows over agricultural fields, carrying these substances into nearby rivers, lakes, and groundwater.

Pesticides can harm aquatic life and disrupt ecosystems, while excess fertilizers, particularly nitrogen and phosphorus, promote algal blooms. These blooms can reduce oxygen levels in the water, leading to dead zones where aquatic organisms cannot survive. Additionally, sediment can cloud the water and carry more pollutants, further degrading water quality and affecting both human health and wildlife habitats.

Understanding this impact is crucial for water management practices and policies aimed at minimizing pollution and protecting water resources.