Greenfield won't be last Iowa town to have drinking water threatened by toxic blue-green algae, environmentalists say

Donnelle Eller | The Des Moines Register

Show Caption Hide Caption Why Iowa’s water quality debate matters to you In early 2018 the Iowa Legislature took a step in addressing Iowa's water quality with a plan to reduce nitrogen and phosphorous levels by 45 percent.

Greenfield is the first city in Iowa to warn residents against drinking its water, fearing contamination from toxic blue-green algae.

But it won't be the last, environmentalists say.

Dozens of Iowa cities and towns rely on lakes, rivers and reservoirs at risk for cyanobacteria — or blue-green algae — to source their drinking water.

Tests on Greenfield's water came back clean for toxins Wednesday, enabling officials to lift a bottled-water order.

And a boil water order was lifted Friday, after leaders wrangled with high turbidity levels that can compromise the system's ability to kill possible disease-causing organisms.

"It's good it wasn't a toxic bloom this time, but it doesn't change the fact there is significant risk in the future," said Josh Mandelbaum, an attorney for the Environmental Law & Policy Center.

"Not every algal bloom will be a toxic one. But the more algal blooms there are, the greater likelihood you'll get a toxic one, and one that will contaminate a water supply," Mandelbaum said.

"We know that there are a lot of places that are vulnerable," since runoff from farms and cities more easily makes its way into surface water used for drinking, said David Osterberg, co-founder of Iowa Policy Project, a research group based in Iowa City.

The group released a report last month, saying blue-green algae blooms are becoming more prevalent in Iowa lakes and rivers.

It points to a 2016 state study that showed 15 of 26 public water systems had detectable levels of microcystins in raw water. None, though, were detected in finished water.

MORE: Iowa nitrogen pollution in the water is getting worse, study shows

Cyanobacteria release microcystins as the cell is dying, and the toxins can be dangerous to people when they're in drinking water.

Microcystins can harm people's livers, cause diarrhea, vomiting, nausea, numbness or dizziness, the U.S. Environmental Protection Agency says.

"The report says cyanotoxins are there," Osterberg said. "There in the water, going into the systems. That gives you a vulnerability."

The Iowa Department of Natural Resources said the study showed the public water systems' treatment was effective at removing the microcystins.

Iowa Policy Project's report also points to state beach advisories for mycrocystins, which spiked 60 percent from 2006 to 2016.

The number dropped to five last year, but the report says the state changed how the tests were conducted and were not comparable.

Des Moines Water Works, which tests daily for cyanobacteria and microtoxins, issued a warning in 2016 that said microcystins had been detected in finished water, although below health advisory levels.

"It's a poison. We're concerned about even a hint of microtoxins. It's an immediate risk to consumers," said Bill Stowe, the utility's CEO.

The utility said was able to shift to the Des Moines River from the Raccoon to avoid any disruption in service to its 500,000 central Iowa residents.

In 2014, Toledo, Ohio, shut down its water supply for nearly a week due to a massive toxic algae bloom on Lake Erie, prompting the U.S. Environmental Protection Agency to issue health advisories on cyanotoxins.

The federal agency is requiring U.S. cities over 10,000 people to monitor their water for toxins over four months between 2018 and 2020.

Osterberg said broad farm fertilizer use and warmer temperatures from climate change are creating more favorable conditions for blue-green algae to grow.

Phosphorus is believed to be the nutrient driving algal blooms, but nitrogen also plays a role, officials say. Farmers use both fertilizers, which are naturally occurring, to grow crops.

"Climate change is exacerbating our heavy, heavy use of fertilizer," Osterberg said.

And he said the state's Nutrient Reduction Strategy, designed to cut by 45 percent the nitrogen and phosphorus entering waterways and contributing to the Gulf of Mexico dead zone, is not ramping up quickly enough to reduce dangerous blue-green algae blooms in Iowa.

His group is calling for the mandatory buffers on all streams within the next decade to help prevent the loss of nutrients that contribute to algal blooms — and the Gulf dead zone, expected to be an area the size of Connecticut that's unable to support aquatic life this summer.

Iowa is prone to a large number of blue-green algae blooms, given a large number of acres devoted to corn, soybean and other crops, Stowe said.

Iowa ranks fifth nationally for its percentage of acres being farmed — close to 86 percent, the U.S. Census of Agriculture shows.

The state is a leading producer of corn, soybeans, pigs, eggs and cattle.

"Go to any lake this time of year, and you're likely to find a thick mat of algae," said Stowe.

He led a 2015 lawsuit that claimed underground drainage tiles funneled high levels of nitrates into the Raccoon River, which the utility paid millions of dollars to clean up. It was later dismissed.

Iowa could see a bumper crop of toxic blue-green algae this year, Stowe said, thanks to intense heat earlier this month, along with torrential rains that likely carried nutrients into waterways.

Scott Tonderum, the Greenfield utility's general manager, said his board plans to discuss ways to better protect the water supplies, which include six wells.

Changes to treatment and added buffers are on the table, he said. "We want to be proactive and make sure we don’t get a huge algae bloom," Tonderum said.