Nutrient Standards

Phosphorus and nitrogen are necessary to sustain life, however, too much of a good thing can cause problems in our waterways.

Excess phosphorous in our streams and lakes causes algae blooms (which look like green gunk in the water), reduces water clarity, and saps water of dissolved oxygen. These effects make waterbodies less appealing for human recreation and can cause fish kills and other ecosystem disruptions.

Nitrogen and phosphorus pollution comes from farm animals, fertilizers, human sewage, cars, and storm-water runoff from highways and parking lots. In general, runoff from farms and urban areas causes the greatest problem, although sewage treatment plants are significant contributors as well.

When excess nitrogen and phosphorus enter waters from discharges, fertilizer run off, and other sources, they cause an explosion of algae or phytoplankton in the water. The algae quickly deplete the dissolved oxygen in the water and then die themselves. Fish and other water creatures leave the polluted area, if they can, or die, if they cannot escape. The resulting dead zone is known as a hypoxic zone. These dead zones occur in lakes and even in streams.

Nitrogen pollution from Midwestern farms contributes to the massive annual “dead zone" in the Gulf of Mexico . In 2007, the dead zone covered 7,900 square miles, an area comparable to the size of New Jersey . At high levels, nitrogen in drinking water can even threaten human health, by interfering with the blood’s ability to transfer oxygen to cells. Nitrogen pollution of well water is responsible for “blue baby” syndrome, a life threatening condition present.

Technologies exist to remove nitrogen and phosphorus from sewage plant discharges, and best management practices such as buffer strips and wetland restoration can reduce pollution from farm runoff.

With assistance from the Washington University Interdisciplinary Environmental Clinic, the Coalition has been working to secure the adoption of nitrogen and phosphorus pollution limits in our state. Nutrient criteria for lakes and reservoirs have been developed, submitted to EPA and are currently awaiting final EPA approval.

Additionally, on March 3, 2010, the Missouri Clean Water Commission approved a Finding of Necessity for rulemaking for nitrogen and phosphorous standards for Missouri's streams -- the rulemaking is scheduled to be finished by the end of 2012. This Finding of Necessity acknowledges that this nutrient criteria rulemaking is necessary to carry out the purposes of the Missouri Clean Water Law. MCE will participate in the relevant steps of the rulemaking, including the stakeholder workgroup process, to ensure that Missouri DNR has all the important information and makes the best decisions for protective nutrient criteria for Missouri's streams.