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Posted on Mon, Aug 17, 2009 : 4:36 p.m.

Huron River phosphorus levels down, University of Michigan study shows

By Juliana Keeping

A 2006 Ann Arbor ordinance that bans lawn fertilizers with phosphorus appears to be reducing phosphorus levels in the Huron River, a new University of Michigan study concludes.

Phosphorus, which can cause algae blooms when it washes into waterways, has dropped an average of 28 percent in the Huron River, according John Lehman, a U-M professor of ecology and evolutionary biology. He and several students co-authored the study.

Lehman had been collecting data since 2003 for a separate study that assessed nutrient levels in the Huron River and Ford and Bellville lakes downstream.


For the new study, students ran chemical analyses on samples taken once a week in 2008 and this summer from the Huron River to determine whether the ban of phosphorus use had any impact on the city's main waterway.

"We had a series of sites we had been testing, and we had a great data set from the original study," Lehman said. "It just so happened it was exactly the right kind of thing needed to assess retrospectively what the effect of a fertilizer ordinance was going to be."

In southeast Michigan, phosphorus - a poisonous, nonmetallic element occurring naturally in phosphates - is plentiful in soil; adding it to lawns is not necessary, Lehman said.

Unused phosphorus will run off into waterways, where it can cause algae blooms. If the blooms die and decay, bacteria doing the decomposition work will suck oxygen from the water, which can kill fish.

Lehman and U-M students Julie Ferris, Douglas Bell and Kahli McDonald collaborated on the data collection and analyses. The paper by Lehman, Bell and McDonald was published online Friday for the Journal of Lake and Reservoir Management.

Research was funded by the city of Ann Arbor, the U.S. Department of Agriculture and the Environmental Protection Agency.

Juliana Keeping covers the University of Michigan for Reach her at or 734-623-2528.


Alan Benard

Tue, Aug 18, 2009 : 12:31 p.m.

A big player in cleaning up the phosphorus in the river is the fairly new water detention pond reconstructed at Mary Beth Doyle Park. Formerly Brown Park, it was re-dedicated on June 1, 2008. The Washtenaw Co. Drain Comission owns the pond and spent two years transforming it from a wide spot in the creek to real wetland. The watercourse now forms a U-shape, with a dam limiting the flow to detain stormwater. Particles in the water have a chance to settle, and plants soak up the phosphorus well before creek reaches the Huron. Cranes and other waterfowl live in the fenced-off wildlife habitat. Walking paths, woods and a playground make it a pleasant spot between I-94 and Packard Road. Map:

Deb Anderson

Tue, Aug 18, 2009 : 9:22 a.m.

Good news for the pro-Argo Pond people? What isn't mentioned is the water levels have been at its highest in 15 years. This would reduce the phosphorus concentrations. Let's see what it is in a dryer year.

Laura Bien

Mon, Aug 17, 2009 : 8:35 p.m.

A drop of 28 percent in a scant 3 years--that is good news.


Mon, Aug 17, 2009 : 6:26 p.m.

let's keep it up! The huron is an awesome resource.

Matt Van Auker

Mon, Aug 17, 2009 : 3:53 p.m.

Excellent, Cool. I don't want to take showers with that kind of crap in my water.


Mon, Aug 17, 2009 : 3:53 p.m.

Excellent news!!