Silt dumping isn’t fueling lake algae
Toledo, Ohio — A federal agency that has resisted calls to stop depositing tons of mud and soil in western Lake Erie said new research shows that the dumping isn’t contributing to the rising number of harmful algae outbreaks in recent few years.
The study released by the U.S. Army Corps of Engineers found that silt dumped into the lake isn’t a primary source of the phosphorus that feeds the algae, which produces toxins that this summer fouled the tap water for 400,000 people in Ohio and southeastern Michigan.
Environmental regulators and political leaders in Ohio have been trying to stop the dumping since the 1980s, arguing that it harms water quality and fish in the lake. The Army Corps has maintained that it’s safe and much cheaper to dump the sediment into the lake than storing it.
Researchers believe as much as two-thirds of the phosphorus in Lake Erie comes from farm fertilizers and livestock manure. Some also comes from sewage treatment plants and leaking septic tanks.
But many environmental groups also have long suspected there was a connection between the increasing algae growth and the dumping of silt in the western end of the lake.
Two members of Ohio’s congressional delegation proposed legislation last week that would force the Army Corps to end dumping sediment from Great Lakes shipping channels into the open water.
A day later, the Army Corps released the results of the 18-month study conducted by two outside engineering consulting firms that concluded dumping dredged sediment in the lake had no measurable impact on the amount of phosphorus in the water.
Two of the main backers of the federal bill — Republican Bob Latta and Democrat Marcy Kaptur, both of northwestern Ohio — said through their offices that the Army Corps’ study did not change their view that the dumping should be stopped.
Latta said that while coming up with the legislation he spoke with a number of experts about what causes the algae growth.
“Preventing the discharge of dredged materials is just one piece of the puzzle,” he said in a statement. “The goal of this legislation is not to shut down or slow navigation channels, but rather implement best management practices for our Great Lakes.”
Kristy Meyer, of the Ohio Environmental Council, said that while depositing sediment in the lake isn’t a main cause of the algae problem, ending the practice will help. There are other environmental reasons to consider as well, she said, including water quality and how dumping affects fish.
Pressure to stop the dumping had been increasing even before Toledo’s water supply was contaminated for two days in early August.
State lawmakers this past spring approved spending $10 million to research alternative uses for the silt dredged from northern Ohio’s harbors. Silt is usually stored because of the costs involved in putting it to a new use. The Army Corps and Ohio’s Environmental Protection Agency pledged to work together on finding new uses.
Ohio EPA Director Craig Butler has set a goal of significantly reducing or eliminating the dumping of sediment dredged from Toledo’s harbor within five years.
Around the Great Lakes, Minnesota and Wisconsin have laws prohibiting nearly all open-water dumping while some other states have taken steps to reduce it.
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