Lake pollution has largely remained unchanged since 1990, despite expanding agriculture, urban development and climate change, says a study of 3,000 lakes in the Midwest and eastern states.
Seven percent of the lakes in the study saw increases in phosphorus — a common component of farm runoff that’s implicated in toxic green-algae blooms. Nine percent of those lakes saw improvements.
“Nitrogen levels in the lakes declined a little — 1.1 percent per year overall — a trend that was apparent primarily in the East, where there’s less farming,” said The Star Tribune, citing Samantha Oliver, the study’s lead researcher at the University of Wisconsin. “The nitrogen declines in the East where largely because of improvements in air quality thanks to the Clean Air Act.”
Some of the solutions that have helped keep lakes clean include “water-quality projects and landowner education about lawn fertilizers and rain gardens,” and “the creation of wetlands and ponds that hold and filter storm water reduces phosphorus.”
The federal government spends about $3.5 billion every year to help maintain the health of lakes in the region, on top of locally funded efforts, which leads some critics to wonder why their haven’t been greater improvements.