Phosphorous causes algal blooms like this one on the shore of Catawaba Island, Ohio. Photo: National Oceanic Atmospheric Administration
By Brian Bienkowski
Phosphorous fertilizers will soon be restricted in Michigan as the state addresses one of the ways the nutrient infiltrates waters and spurs the creation of zones of low oxygen that harm aquatic life.
The ban begins next January. Exempt are new lawns and those that test low for phosphorous, farmers and golf courses where management has taken a state-approved fertilizer training.
Michigan is one of five Great Lakes states with limits on the nutrient that promotes algae and weed growth in water. When the weeds die, the bacteria that feasts on them sucks up the oxygen in the water and creates dead zones that kill fish and other aquatic species.
Minnesota and Illinois already had similar limits in place while New York’s restrictions will take effect next January. Wisconsin is reviewing existing restrictions.
The goal is to keep phosphorous from settling into lakes and streams. Fertilizer that gets onto pavement, frozen ground or compacted soil will run off into lakes and streams.
Michigan recently banned phosphorous in dishwashing detergents. It banned phosphorous-heavy laundry detergents decades ago. Although a naturally occurring element, the near shore areas of the Great Lakes have had consistently elevated levels of phosphorous due to human use. According to the EPA’s “State of the Great Lakes” report, in 2009 four of the five lakes had elevated levels in the nearshore areas.
“This creates problems outside of threats to ecosystems,” said John Nevin, public affairs advisor of the International Joint Commision, an agency that advises the U.S. and Canada on water issues. “This affects the quality of drinking water, causes illness in swimmers, disrupts fisheries and leads to beach closures.”
Fertilizer is not the only culprit. Agricultural run-off, inadequate municipal wastewater and residential septic systems, industrial livestock, ecosystem changes from invasive mussels, and climate change impact are all likely factors, according to a recent report by the International Joint Commission.
Michigan’s ban only applies to commercial and residential lawns. Farm restrictions don’t seem to be on the horizon.
“Farmers routinely check their soil and are very aware of nutrient levels,” said Robin Rosenbaum, plant industry section manager at the Michigan Department of Agriculture and Rural Development. “They typically don’t use any more fertilizer than they need to.”
Those who were active in lobbying for the bill recognize agricultural use as a significant contributor to the problem, but, nonetheless, credit the legislation for taking a step in the right direction.
“It (agricultural use) is certainly a contributor but at this point it is not reasonable to ban phosphorous in agricultural applications,” said Hugh McDiarmid, communications director at the Michigan Environmental Council. “But we do need to continue efforts to educate both farmers and those at golf courses on responsible fertilizer use.”
The statewide restrictions have been discussed since 2003; opposition was light, Rosenbaum said. A uniform ban across the state makes it easier on everyone, including fertilizer manufacturers, McDiarmid said.
“It is a common sense approach agreed to by multiple stake holders and it enjoyed strong bi-partisan support with legislators as a result,” Jeff Fedorchak wrote in an email. He is vice president of government affairs at ServiceMaster, a large fertilizer company with a family of brands that includes Trugreen and Terminix.
ServiceMaster partnered directly with the Michigan Environmental Council to support the legislation.
Several counties and cities had bans in place prior to the bill making it difficult for fertilizer companies. Those with existing phosphorous restrictions will have them grandfathered but state law will trump any restrictions put forth by municipalities moving forward.
The success of these local restrictions helped push the law through, said Laura Rubin, executive director of the Huron River Watershed Council. The city of Ann Arbor adopted a ban in 1997 that also exempts agricultural uses. The council found a 36 percent decrease in phosphorous levels at urban-area creeks between 2003 and 2008, according to a 2009 report.
“We have seen a definite trend of reductions in phosphorous since the fertilizer restrictions,” Rubin said. “The greater reductions in urban areas speak to the effectiveness of the ordinances.”
The ban will be enforced by the state Department of Agriculture and Rural Development through periodic testing of lawns treated by fertilizer companies. It will largely be “complaint based,” Rosenbaum said, but the department will check in regularly with companies who apply fertilizers.
While the restrictions will address at least a part of the problem, scientists still aren’t exactly sure where all of the phosphorous is coming from, Nevin said.
“What we need is more monitoring and a regular review of inputs into the lake. Before we can stop it we need to answer the question – where is it coming from?”