A Maximum Contaminant Level (MCL) in drinking water of 10 mg/L nitrate as nitrogen was established by the Environmental Protection Agency (EPA) because of possible toxic effects to infants and is applicable to any supply that may be used for drinking water.
The EPA established a goal for total phosphorus concentration of 0.10 mg/L to limit cultural eutrophication of flowing water. Larger concentrations also may interfere with coagulation in water-treatment plants.
The EPA also establishes recommended criteria for nutrients based on aggregate Level III nutrient ecoregions and subecoregions.
Most of the Kansas River basin is in ecoregion V (South Central Cultivated Great Plains). As it nears the Eastern end of the state, the river also flows through ecoregion IV (Great Plains Grass and Shrublands), ecoregion VI (Corn Belt and Northern Great Plains), and ecoregion IX (Southeastern Temperate Forested Plains and Hills).
The recommended criteria defined by each aggregate ecoregion may be found in the following table:
More information about nutrient ecoregions is available at: http://www.epa.gov/waterscience/criteria/nutrient/ecoregions/rivers/index.html
New EPA web site on nutrient pollution policy: http://epa.gov/nandppolicy
New EPA web site on nutrient pollution for homeowners, students, and educators: http://epa.gov/nutrientpollution