Scientists predict toxic algal bloom in western Lake Erie

Sarah Rahal
The Detroit News
A sample glass of Lake Erie water near the City of Toledo water intake crib, in August 2014.

Predictions released this week bolster earlier forecasts that possibly toxic algae will form in western Lake Erie this summer, with a bloom that's more harmful than last year's but less severe than the one that fouled Toledo's drinking water five years ago.

National Oceanographic and Atmospheric Administration scientists expect this summer's bloom to measure higher than a 7 on a severity index that typically runs from 1 to 10, saying it could reach a maximum of 9. That would be an increase from last year, which was ranked at 6.

A key factor this year: Rain.

Phosphorus runoff from nearby farms using fertilizer affects the severity of algae blooms. As phosphorus gets into the lake, it feeds existing plants.

Frequent rainfall this spring has increased phosphorus runoff, said Richard Stumpf, an oceanographer for NOAA who studies harmful algal blooms.

"It’s been raining and raining; a lot of water has been running off the land this year and the same thing that happened in 2011 and 2015, when it was the greatest," Stumpf said. "It carries the phosphorus into the water."

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The severity levels were at an 8 in 2017 and a mild bloom in 2016 ranked at 5.5. The largest blooms, 2011 and 2015, were 10 and 10.5. That 2015 bloom covered an area the size of New York City, officials said. 

The severity index is based on the harmfulness of algae over a period of time. Contamination in 2014 left more than 400,000 people in Toledo and parts of southeast Michigan unable to drink tap water for two days. 

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The projection also includes the possibility of additional rain over the next several weeks, researchers said. 

The forecast is estimated based on a combination of measurements and forecasts of phosphorus loads into July. Researchers will not be able to release official forecasts for the season until July 11, when the phosphorus loads from the spring are measured.

So far, phosphorus loads accumulated from the Maumee River near Waterville, Ohio, have exceeded 2014 records. 

NOAA researchers say it's too early to tell how much phosphorus could get into the drinking water but they are developing tools to predict the toxicity. 

Stumpf said he doesn't expect the bloom to be more harmful than 2014 due to advances in technology and monitoring. 

"What happened in Toledo was a large amount of toxin that showed up early in the intake and it was a perfect storm of events, physical and biological, that contributed and unfortunately landed right on the Toldeo intake," Stumpf said. "2014 is still the worse toxic bloom we measured in any of the years."

Stumpf said the easiest way to prevent toxicity is to cleanse the water of the cells by injecting activated charcoal into the lake. 

"If the cells break, the toxins get into the water and if the toxins in the water dissolve, you have to use chemicals to get rid of it and it's much harder to do," he said. 

Gov. Gretchen Whitmer and other Great Lakes leaders have taken steps to reduce phosphorus loading in Lake Erie, at least in the long run.

Whitmer signed an executive directive Thursday instructing the departments of Agriculture and Rural Development; Environment, Great Lakes and Energy; and Natural Resources to submit annual progress reports on efforts to cut pollution in the lake.

Michigan adopted guidelines — known as the Michigan Domestic Action Plan — last year for making Lake Erie healthier, including cutting phosphorus loading into its western basin 40% by 2025.

Whitmer’s directive focuses on lessening nutrient inflows from the Detroit River, the River Raisin and the Maumee River.

"Building on the positive steps taken by the departments to date, we must take additional action to ensure Michigan meets its specific DAP objectives, including reducing the nutrient loadings from priority tributaries and associated watersheds," Whitmer said in her directive.

She joined Ohio Gov. Mike DeWine and Ontario Premier Doug Ford last week in renewing their jurisdictions’ previous commitment to the 40% nutrient reduction goal.

The harmful bloom of the blue-green algae in Lake Erie can produce toxins that pose a risk to drinking water, can cause skin irritation and can negatively impact wildlife, pets and livestock. 

Contact with humans may cause a skin rash, hives, or skin blisters. Inhalation of water droplets can cause runny eyes and nose, sore throat and asthma-like symptoms, or allergic reactions. If the water is ingested, it can cause abdominal pain, headaches, sore throats, nausea, vomiting, dry cough and pneumonia.

Blooms affect not only drinking water but the marine ecosystems and economy, especially for coastal communities dependent on income generated through fishing and tourism, Stumpf said.  

"People often try to avoid Lake Erie and cancel boating trips they have, but we don't recommend that," he said. "We try to emphasize that the whole lake isn't covered in bloom. You can come fish. People will tell you the best places and if you don't want to fish in scum, visit the bulletin to know where to go."

NOAA issues bulletins twice a week during the bloom season providing a three- to five-day forecast.  

Associated Press contributed.