Fertilizer Limits Sought Near Lake Erie to Fight Spread of Algae

A United States-Canadian agency called on Wednesday for swift and sweeping limits on the use of fertilizer around Lake Erie to reduce the amount of phosphorus entering the water and creating a vast blanket of algae each summer, threatening fisheries, tourism and even drinking water.

In a report on the algae problem, the agency, the International Joint Commission, said that fertilizer swept by rains from farms and lawns was a major source of phosphorus in the lake. It recommended that crop insurance be tied to farmers' adoption of practices that limit fertilizer runoff, and that Ontario, Ohio and Pennsylvania ban most sales of phosphorus-based lawn fertilizers.

The commission, which studies and regulates water uses in streams and lakes along the border of the United States and Canada, urged Michigan and Ohio to invoke the Clean Water Act to limit phosphorus pollution from farmland as opposed to from factories and other places where pollution can be pinpointed and measured.

The proposals are likely to encounter strong opposition from the agricultural industry and fertilizer manufacturers. Both groups have already asked a federal appeals court to prohibit the Environmental Protection Agency from regulating farm-related pollution from phosphorus and other chemicals along the Chesapeake Bay.

Phosphorus - and especially phosphorus in fertilizer, which is designed to be easily absorbed by plants - is the source of the algal blooms, some of which are so toxic that they have killed dogs and sickened swimmers. Beyond clotting the lake's surface, decomposing algae consumes the oxygen in the lake's deep center each summer, creating a dead zone where deepwater fish that are essential to the lake's food chain cannot exist.

National and state governments rid the lake of algae in the 1980s, ordering big cuts in phosphorus pollution from factories and sewage plants. But the blooms returned in the late 1990s as farmers started applying fertilizer on frozen fields in the winter, and spreading or spraying it instead of injecting it into the ground.

In 2011, heavy spring rains washed so much phosphorus into the lake that the succeeding summer, algal bloom, at 1,920 square miles, was three times bigger than any previous one.

That and other large blooms have crippled tourism in a region where sport fishing and lake recreation are major industries, and they have forced towns and cities to filter and even shut off drinking water. The multibillion-dollar commercial fishing industry could be hit hard. The lake's growing dead zone has prompted deepwater fish to move upward in search of oxygen, only to run into warmer waters that they find hard to tolerate. Deepwater fish such as perch - a favorite food of one big commercial fish, the walleye - could suffer if the dead zone continues to expand.

'The long-term potential impact on fisheries is something we're really worried about,' said Donald Scavia, a scientist at the University of Michigan's Graham Environmental Sustainability Institute.

Although the sources of phosphorus range from leaky septic tanks to storm sewers to ordinary rainfall, the biggest contributor is farming, the report indicates - and the biggest farm source is the fields along the Maumee River watershed in Ohio and Indiana.

Both the United States and Canada have set targets for reducing Erie's phosphorus load by 2018, but the commission's report states that those targets are too low. To return the lake to the mostly algae-free state it enjoyed in the mid-1990s, it states, the Maumee's phosphorus runoff must be cut by 39 percent.

Both governments and private organizations conduct programs that encourage farmers to voluntarily limit fertilizer runoff, but regulatory limits are mostly nonexistent. The commission's report urges a mix of voluntary and legal programs to achieve large reductions by 2022, with a focus on dissolved reactive phosphorus, the sort used in fertilizers.

The report also states that farmers in lakeside states and provinces should prohibit spreading fertilizer on snowy or frozen ground, where it is most likely to be carried away by melting or rains, and should limit applications in the fall.

For homeowners, the report recommends that Ontario, Ohio and Pennsylvania ban the sale of phosphorus-based lawn fertilizers except during the first growing season of new lawns, or when soil tests show that the phosphorus content is too low. It also says that Michigan and Ontario should require inspections of septic tanks to ensure they do not leak.