WEDNESDAY, Aug. 26, 2009 (HealthDay News) -- Banning or restricting the use of certain types of lawn fertilizers can improve water quality in nearby lakes and streams, new research shows.
Rain and runoff can cause lawn fertilizers that contain phosphorous to leach from the soil into waterways, killing fish, causing foul-smelling algae blooms and disrupting the marine ecosystem.
As awareness of the problems has increased, municipal and county governments around the nation have prohibited or restricted the use of the fertilizers. Some ban their use outright, while others limit usage to the first year the lawn has been planted or to phosphorous-deficient soil.
To determine the effectiveness of the legislation, researchers analyzed water samples from the Huron River, which flows through southeast Michigan. In 2006, nearby Ann Arbor, Mich., limited the use of phosphorus-containing fertilizers.
The study found that phosphorus levels dropped 28 percent in the three years after the ordinance took effect.
Southeast Michigan soil tends to have adequate phosphorus, researchers noted, making fertilizing lawns with the nutrient unnecessary in most cases.
Until this study, there was little scientific research confirming that fertilizer restrictions are an effective means of protecting waterways from damaging runoff, John Lehman, a professor of ecology and evolutionary biology at the University of Michigan, said in a news release from the school.
"It's one of those things where political organizations take the action because they believe it's the environmentally conscious thing to do, but there's been no evidence offered in peer-reviewed literature that these ordinances actually have a salutary effect," Lehman said.
The study was published in the Aug. 14 online issue of Lake and Reservoir Management.
The U.S. Environmental Protection Agency has more on the impact of fertilizers containing phosphorus.