National Water-Quality Assessment Program

Nutrients in the Nation's Waters--Too Much of a Good Thing?

[Electronic version of Circular 1136]

Published 1996.

Nutrients are essential for plant and animal growth and nourishment, but the overabundance of certain nutrients in water can cause a number of adverse health and ecological effects. To determine the extent of nutrient and other types of contamination in the Nation's streams and ground water, we analyzed data from about 12,000 ground-water samples and more than 22,000 surface-water samples collected at more than 300 sites between October 1979 and September 1990. Most samples had been collected within NAWQA study units. Nutrient concentrations in water generally are related to land use in the upstream watershed or the area overlying a ground-water aquifer. Nitrate concentrations were generally higher in ground water than in streams. Concentrations were highest in the Northeast, Great Plains, and along the West Coast. Drinking water from public-supply wells and domestic-supply wells outside of agricultural areas is not likely to have high levels of nitrate. Domestic-supply wells in agricultural areas are more prone to increased concentrations. Ammonia and phosphorus concentrations in surface water are highest downstream from urban areas. Where these concentrations are high, they warrant concerns about decreased oxygen in the water, toxicity to fish, and accelerated eutrophication.

• Table of Contents
• Printed copies of the report are available upon request to the NAWQA Program office.

U.S. Department of the Interior, U.S. Geological Survey Maintainer: Kerie Hitt (kjhitt@usgs.gov) Last update: 09:55:34 Mon 19 Aug 2002 Privacy Statement || Disclaimer || Accessibility URL: http://water.usgs.gov/nawqa/CIRC-1136.html