Lake Erie free of toxicity in algae bloom

Sarah Rahal
The Detroit News

Months after reports predicted possible toxic algae bloom forming in western Lake Erie this summer, researchers now say, "we're in the clear."

Last week, the bloom continued in the western basin of Lake Erie extending up Michigan shore, but winds reaching 25 mph between Monday and Thursday helped promote the slight mixing of surface waters. The key to ending the bloom is high winds when the temperature starts dropping, said Richard Stumpf, oceanographer with the National Centers for Coastal Ocean Service.

"There is still a bloom, but it has not been particularly strong this year," said Stumpf. "Typically, the bloom reaches max concentration in early September, but on the good side, there has been little scum in the lake during the small bloom and it's windier than usual."

Algae covers the surface of Maumee River at the mouth of Lake Erie in Toledo in November 2017. This year the bloom, which was strongly visible in July, was less severe than previous ones that contaminated drinking water.

Stumpf said the toxicity is low, but are still cautioning people entering the water until the end of September. 

"If you compare it to last year when there was scum from downtown Toledo to Ontario, we're in the clear.

"The most toxic is at the beginning of each bloom so, we are clear of toxicity and it's not a concern," he said. "Right now, the toxicity is at levels normal water treatment can handle... It takes a while for everything to come down. Sometimes we see a reappearance in late September and we're only halfway through."

The bloom, which was strongly visible in July, was less severe than previous ones that contaminated drinking water. Too early to tell, but it possibly ranked a 6 or less, he said. 

The severity index (on a scale of 0 to 10) is based on the harmful algae over a period of time during a bloom. Contamination in 2014 left more than 400,000 people in Toledo and parts of southeastern Michigan unable to drink tap water for two days. 

The largest blooms recorded were in 2011 and 2015, which ranked at a 10 and 10.5 respectively. That 2015 bloom covered an area the size of New York City, officials said. 

One factor contributing to the severity of algae blooms is phosphorus runoff from nearby farms using fertilizers. This gets into the lake and feeds the existing plants.

Jason Morgan, a supervisor at Wm.C. Sterling State Park near Monroe, said field staff observed this year has been surprisingly unlike years past.

"Although a heavy presence of algae over the past several years was not an uncommon occurrence, this year was surprisingly milder with regards to algal blooms that were observed from the beach and within the lagoons," he said. "This year has not been like years past regarding murky/discoloration and odor with coastal waters. That’s not to say it was nonexistent, just that it appeared in milder concentrations and therefore went easily unnoticed."

Morgan said the beach has been favored by park guests and has not been under any advisories restricting water entry based on algal blooms.

Twitter: @SarahRahal_