Fact Sheet

Nutrient Pollution


Mississippi River

NCEL Point of Contact

Chris Askew-Merwin
Sustainable Agriculture and Water Specialist



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.

Key Points

Key Point 1

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

Key Point 2

Improving river health requires cross-state collaboration and a watershed approach to management of issues like water quality, infrastructure, and flooding. (1 Mississippi)

Key Point 3

In the Mississippi River, 39 percent of streams have high levels of nitrogen and 32 percent of streams have high levels of phosphorus, above the national average. (EPA)

Key Point 4

Economic activity connected to the Mississippi River generates $497 billion annually and supports 1.5 million jobs, all of which depend on a healthy river. (UNEP)


Nutrient monitoring, trading, and reduction legislation:

  • Wisconsin Phosphorus Water Quality Standards and Arkansas HB 1067 (2015) provide authority for water quality trading programs.Ohio Senate Bill 1 (2015) limits the application of fertilizer and manure in certain conditions. 
  • Minnesota SF 297 (2017) creates water testing for certain contaminants and establishes best practices.

Buffer zone legislation:

  • Minnesota Statutes 2016, Section 103F.48, amended by SF 844 (2017), establishes set buffer zones for all designated public waters.
  • Maine Mandatory Shoreland Zoning Act requires specific land use controls for certain water bodies.


NCEL Resources

Online Resources

Reports on Nutrient Pollution - EPA

A collection scientific reports and case studies on nutrient pollution from the U.S. Environmental Protection Agency.

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Decades of Delay Report - Mississippi River Collaborative

A detailed report on the gaps in protections against nutrient pollution and steps Mississippi River states can take.

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Illinois Nutrient Loss Reduction Strategy Report

This report is intended to guides Illinois' efforts to improve water quality at home and downstream by reducing nitrogen and phosphorus levels in lakes, streams, and rivers.

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Mississippi River Basin Conservation Network Fact Sheets

MRBCN fact sheets by state and issue area.

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