Statement on Duckweed in the Chicago River

“The duckweed that people are reporting in the Chicago River is an object lesson in how the river health is impacted by nutrient pollution, sewer overflows, and climate change,” said Friends of the Chicago River in a statement.

“The extreme conditions of heat, heavy rain, and too much nitrogen and phosphorus have caused this otherwise innocuous native plant to proliferate in some parts of the river. While likely not causing any problems now, if enough of it grew it could block sunlight for other aquatic plants, deplete oxygen, and foul water infrastructure.

Friends is advocating for stronger nutrient standards with the Illinois EPA, and this unwanted increase in duckweed is a good reason why they should be approved.”

Friends reported the appearance of duckweed to the Metropolitan Water Reclamation District of Greater Chicago on Monday evening.