• Twitter - Grey Circle
  • YouTube - Grey Circle
  • Facebook - Grey Circle

Understanding Chicago's role in the Gulf of Mexico dead zone

January 16, 2018

One of the many environmental problems that Earth faces today is the dead zone in the Gulf of Mexico, where 8,774 square miles are uninhabitable by fish and other aquatic life due to extremely low oxygen levels. These low oxygen levels are caused by nutrient (phosphorus and nitrogen) pollution in waterways that flow into the Gulf of Mexico through the Mississippi River. Over a century ago, the Chicago River was intentionally reversed in order to divert sewage from entering Lake Michigan. However, an unintentional consequence was the phosphorus pollution carried from Chicago, through the Mississippi River, and into the Gulf. Because of this, Chicago is now the single largest contributor of phosphorus pollution to the Gulf of Mexico's dead zone.


Gulf of Mexico dead zone in July 2017

At 8,776 square miles, this year's dead zone in the Gulf of Mexico is the largest ever measured.

(Courtesy of N. Rabalais, LSU/LUMCON)



What is phosphorus and why is it so significant? 


The Earth Institute of Columbia University in New York City states:


Phosphorus, the 11th most common element on earth, is fundamental to all living things. It is essential for the creation of DNA, cell membranes, and for bone and teeth formation in humans. It is vital for food production since it is one of three nutrients (nitrogen, potassium and phosphorus) used in commercial fertilizer. Phosphorus cannot be manufactured or destroyed, and there is no substitute or synthetic version of it available. 


When excess phosphorus enters bodies of water, it makes the bodies of water uninhabitable for marine life by spurring algae growth and choking oxygen levels. In fact, most excess phosphorus enters waterways, which is why dead zones are so prevalent, not only in the Gulf of Mexico




Dead zones around Earth

(Courtesy of NASA)



What is the source of phosphorus pollution in Chicago? 


Human waste through toilets, agricultural fertilizers, uncleaned pet manure on walkways, and other organic wastes in sewage and industrial outflow contribute to phosphorus pollution in waterways.



How is Chicago handling their phosphorus pollution? 


The Metropolitan Water Reclamation District of Greater Chicago (MWRD) has employed technologies in its water treatment process to recover phosphorus from raw sewage and stormwater runoff before it hits the river. Ostara Nutrient Recovery Technologies, equipment capable of recovering dissolved phosphorus, has been installed at MWRD's Stickney Water Reclamation Plant. There has been great success from the implementation of the Ostara technology so far; however, the Stickney Plant is the only MWRD plant that uses this technology. There are seven water reclamation plants.



How can you prevent excess phosphorus from entering waterways at home? 


  • Always clean up after your pet. If you don't, it will eventually end up in a waterway (Source: MWRD)

  • Say goodbye to pesticides and fertilizers on your lawn with these alternatives (Source: Midwest Pesticide Action Center)

  • Choose unprocessed, chemical-free foods and beverages. Not only will you be helping water but you also will be helping your health. (Source: MWRD)

  • Prevent soil erosion and agricultural runoff by promoting no-till farming, terracing, contour tilling and the use of windbreaks (Source: State of the Planet)

  • Eat a plant based diet. Less meat consumption means less animal waste entering waterways. (Source: State of the Planet)

  • Reduce food waste from farm to fork. Prepare recipes ahead of time in order to make grocery shopping as efficient as possible. (Source: State of the Planet)



An overview of how the Chicago River connects to the Mississippi and then the Gulf of Mexico 

(Courtesy of Raft the Mississippi River)




Share on Facebook
Share on Twitter
Please reload