What is the primary source of phosphorus pollution in waterways?

The primary source of phosphorus pollution in waterways has been identified as runoff from agricultural land containing excess fertilizer. When fertilizers that are high in phosphorus are applied to crops, not all of the nutrient is absorbed by the plants. Rainfall and irrigation can cause this excess phosphorus to wash away from the fields and into nearby streams, rivers, and lakes, leading to nutrient pollution.

This runoff contributes significantly to the eutrophication process, which encourages excessive algal blooms in water bodies. These blooms can deplete dissolved oxygen levels, harming aquatic life and disrupting ecosystem balance.

While urban runoff, industrial discharge, and wastewater treatment plants can also contribute to phosphorus levels, agricultural runoff is particularly significant due to the volume of land used for agriculture and the high application rates of phosphorus fertilizers. Thus, understanding the role of agricultural practices in nutrient management is crucial for effective environmental stewardship and the protection of water quality in Maryland and similar regions.