How does agricultural runoff affect water quality?

Agricultural runoff significantly impacts water quality primarily by introducing pesticides and nutrients into water systems. When rainfall or irrigation occurs, excess fertilizers used in agricultural practices can wash away into nearby rivers, lakes, or streams. This runoff often contains high levels of nitrogen and phosphorus, which are essential nutrients for plant growth but can lead to detrimental effects in aquatic environments when present in excess.

The introduction of these nutrients can cause algal blooms, which can deplete oxygen levels in the water and harm aquatic life. Additionally, pesticides used to control pests and diseases in crops can also be carried into water bodies, potentially affecting not only the organisms within those ecosystems but also humans who rely on that water for drinking or recreational purposes.

By understanding the mechanism of agricultural runoff and its contribution of harmful substances to water bodies, it highlights the importance of managing agricultural practices to minimize negative impacts on water quality.