Toledo resident Lauren Birner's kitchen sink has looked a bit odd the past few days. Birner, who is 15 weeks pregnant, took extra precautions to keep herself from accidentally turning on the tap during the city's recent water ban.
"I put plastic bags over the faucets because, without thinking, I would turn on the faucet, and think, 'Oh, wait!'" she says.
The ban was put in place Saturday and lifted Monday. Experts suspect that a big algae bloom on Lake Erie produced toxins that got into the water supply, affecting hundreds of thousands of people in Ohio's fourth-largest city.
Algae blooms have been growing on Lake Erie for years. The Ohio Sea Grant Research Lab told the Associated Press this year's bloom was smaller than in years past but it was pushed toward shore by wind and waves.
A number of factors make the algae flourish. Experts point to global warming and to fertilizer run-off from farm fields. "Algae blooms love fertilizer the same way wheat and corn love fertilizer," says Charles Fishman, author of "The Big Thirst," a book about water.
Fishman says when algae die, they produce a toxin, and that toxin appears to have gotten past Toledo's water treatment plant. Fishman fears the situation could happen on the other Great Lakes. That should put cities on guard, he says, especially if they rely on a single water source.
Fishman says the situation was not catastrophic in Toledo, but it could have been graver. "If this had happened in the middle of the week, it would've had a huge economic impact," he says.
Experts say there are ways to mitigate problems tied to algal blooms, like improving water treatment facilities or getting farmers to grow crops that need less fertilizer, even if they're less lucrative.
"A lot of farmers would see costs go up and revenues go down," says David Zetland, a water economist at Leiden University College in the Netherlands.
The state of Ohio has tried to address problem. Legislators passed a law this year requiring that farmers get training before using commercial fertilizers.
But Alan Vicory, a principal in the water practice at Stantec Consulting in Cincinnati, says it's not clear what quantities of the fertilizer components nitrogen and phosphorous cause an algae bloom outbreak.
"We have been working on this as a community of scientists and engineers for many years, and it's very difficult," he says. "It's confounded our ability to tie all those things together to have any predictive capability as to an outbreak."