Cyanobacteria blooms continue to plague Lake Erie. Farms and wastewater have gotten a lot of attention for contributing nutrients that create these harmful blooms.
More recently, the spotlight has focused on lawn care. Grass fertilizers can also contain phosphorus that winds up in waterways. Michigan and other states around the Great Lakes have already banned lawn fertilizers that contain phosphorus. Now international regulators and others are pushing Ohio and Pennsylvania to do the same.
Greener grass and a greener lake
Michael Pelletier is spreading fertilizer pellets in the grass of a manicured, park-like area, behind a new business development.
“Once the fertilizer starts to work, you’ll see the color improve, the turf will fill in, some of these thin areas in the shade will fill in a little more, it’ll recover from the winter damage, the plants should be strong, healthy, dense turf,” he says.
Pelletier has been doing this kind of work for more than 30 years.
But these days, fertilizer is getting a bad name because it can run off the land and into waterways. The Great Lakes, particularly Lake Erie, have been choked with cyanobacteria blooms (sometimes referred to as blue-green algal blooms) in recent years. And fertilizer ingredients such as nitrogen, and especially phosphorus, are getting much of the blame.
Dave Dempsey is a policy advisor at the International Joint Commission.
“Well, it’s fertilizer, and so what happens is when it runs off it fertilizes the water, literally,” he says.
The IJC regulates the lakes and rivers along the U.S.-Canadian border. Dempsey says nearly every state and province bordering the Great Lakes limits phosphorus in lawn fertilizers. In a report earlier this year, the IJC called on Ontario, Ohio, and Pennsylvania, to take action. They are the only three without phosphorus bans.
Dempsey says it's common sense.
“Most lawns don’t need phosphorus to begin with. Most have enough in the soil. We’re essentially just putting phosphorus on the ground to run off, we’re wasting money as consumers, and we’re creating an environmental problem,” he says.
Michigan’s law limits nitrogen and bans phosphorus in many lawn fertilizers. It’s similar to laws in other Great Lakes states, and to a bill that’s been introduced in Pennsylvania.
In response to these laws, companies that make fertilizers have already reformulated their products. But the Pennsylvania Lawn and Nursery Association still opposes the law because it says it will cost professional lawn care companies and consumers more money.
Michael Pelletier says under the Pennsylvania law, he would be required to apply fertilizer at reduced rates.
“If lawn care companies have to reduce the amount of fertilizer they put down each time, and have to come out more frequently, it’s going to be more expensive. Absolutely.”
But Pelletier already uses fertilizer without phosphorus. It’s cheaper.
Researchers see results in the Huron River
In Michigan, researchers have found taking phosphorus out of fertilizer is making a difference.
John Lehman is a biologist at the University of Michigan. He’s been studying the Huron River for more than a decade. He found a big change in 2008, after the city of Ann Arbor started limiting lawn fertilizers.
“Frankly, I was quite surprised that even after the first year, we could see an effect,” he says.
Lehman says the ban reduced phosphorus in the river by 25%.
“If it was only one year, we’d have to think that that was perhaps coincidental, but we saw it repeated three years in a row.”
Since then, the state of Michigan and others in the Great Lakes have passed limits on lawn chemicals. Lehman says the health of Lakes Michigan and Superior has improved in recent years. But Lake Erie is still the most polluted with fertilizer nutrients, and has the most trouble with cyanobacteria blooms.
Clarification: An earlier version of this story referred to "algae blooms" in Lake Erie. These are really bacterial blooms (cyanobacteria) that look like algae. The copy has been clarified above.
