Nutrient Pollution Reduction Excessive inputs of nitrogen and phosphorous can spur algae growth and create hypoxic and dead zones

The Problem

Nutrient pollution is when an overabundance of nutrients, like nitrogen and phosphorous, enter the water system. These nutrients are natural, but in high quantities they can lead to an overgrowth of algae–known as “blooms”–and decrease oxygen that fish and other aquatic life need to survive.

The primary sources of excess nutrients are runoff from fertilizers and animal manure, discharges from domestic and municipal sewage systems, and stormwater runoff. Nutrient pollution is detrimental to human health and the economy, with U.S. tourism losing close to $1 billion each year from impacts to fishing and recreation. Excessive nitrogen is also a common drinking water contaminant and particularly harmful for infants.

City of St. Louis skyline.

Fast Facts

Nutrient pollution threatens drinking water and the ecological stability of rivers and lakes through algal blooms and hypoxic zones.

Improving river health requires cross-state collaboration and a watershed approach to management of issues like water quality, infrastructure, and flooding.

Only 1.6% of rivers and streams in the 10 state Mississippi River corridor are tested for phosphorus, and 0.6% are tested for nitrates.

Economic activity connected to the Mississippi River generates $405 billion annually and supports 1.3 million jobs, all of which depend on a healthy river (USFWS).

NCEL Projects

NCEL has two regional efforts underway that incorporate nutrient pollution reduction. Click on the images to learn more. 


State governments have proposed and implemented a number of successful strategies for healthy rivers. Many of the policies below were crafted with the involvement of the local agricultural communities, such as Farm Bureaus.

Nutrient monitoring, trading, and reduction legislation:

Buffer zone legislation:

Science and Reports

State of the River Report

This report by the Friends of the Mississippi River and US National Park Service includes 14 key indicators of water quality and ecological health in the river, including swimming and recreation, flow and hydrology, and river life.

Minnesota Nutrient Reduction Strategy

This strategy guides the state in reducing excess nutrients in waters so that in-state and downstream water quality goals are ultimately met.

Illinois Nutrient Loss Reduction Strategy

This strategy guides state efforts to improve water quality at home and downstream by reducing nitrogen and phosphorus levels in our lakes, streams, and rivers.

Illinois Farm Bureau Water Quality Report

The annual water quality report from the Illinois Farm Bureau, which describes the achievements of current programs and details future plans to address water quality.


  • NCEL Fact Sheet with key points and links to legislation. 

  • This report zeros in on the Midwest and offers a first step toward defining the range of potential economic consequences to this particular region if we continue on our current greenhouse gas emissions pathway. Interactive graphics and detailed research is included by region. 

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  • The Collaborative is a collection of environmental organizations and legal centers from states bordering the Mississippi River. Their website offers links to groups working on specific issues, as well as detailed issue pages that provide an overview of issues such as nutrient pollution and dead zones. The full website can be viewed here

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