Phosphorus levels in the Huron River dropped an average of 28 percent after Ann Arbor adopted an ordinance in 2006 that curtailed the use of phosphorus on lawns.
Municipalities around the country are banning or restricting the use of phosphorus-containing lawn fertilizers, which can kill fish and cause algae blooms and other problems when the phosphorus washes out of the soil and into waterways.
Do the ordinances really help reduce phosphorus pollution? That was the objective of a research project conducted at the University of Michigan by John Lehman, professor of ecology and evolutionary biology at the University of Michigan and students Douglas Bell and Kahli McDonald. Their paper, appearing in the journal Lake and Reservoir Management, published online Aug. 14, shows that phosphorus levels in the Huron River dropped an average of 28 percent after Ann Arbor adopted an ordinance in 2006 that curtailed the use of phosphorus on lawns.
"Right away, we started to see decreases," Lehman said. After the first year of data collection, it was clear that phosphorus concentrations were lower after the ordinance was enacted than before.
But did the ordinance cause the drop? Though that explanation seems likely, public education efforts and general increased environmental awareness among Ann Arbor residents also may have entered in.
The Southeast Michigan Council of Governments (SEMCOG), invited Lehman to present the study results at a meeting earlier this year. Due to the importance of the data, the study may well generate interest beyond Michigan's borders.
"Although the science wasn't difficult, its ramifications in a political sense and in an environmental sense will not be insignificant," Lehman said.
Photo shows the Huron River.
For more information: http://www.ns.umich.edu/htdocs/releases/story.php?id=7272