Why do nutrient loadings to some rivers and streams need to be reduced?
As of 1996, about 40% of the nation’s surveyed rivers, lakes, and estuaries were too polluted for basic uses like fishing and swimming. High concentrations of nutrients were one of the leading causes of water quality problems. The 2000 National Water Quality Inventory revealed that nutrients are the most widespread pollutants impacting surveyed estuaries; and nutrients and metals are the most widespread pollutants impacting surveyed lakes. Aquatic ecosystems require some nutrients in the water; but excessive amounts of nutrients can harm aquatic life and human health. For example: • High concentrations of phosphorus are often responsible for accelerated eutrophication in lakes, streams, and reservoirs. Eutrophication can lead to algal blooms, fish kills, foul odors, and excessive aquatic weed growth. • Drinking water with high concentrations of nitrate (a form of nitrogen) can reduce oxygen transport in the bloodstream. In extreme cases, this can lead to “blue baby syndrome” in infants
