Algae toxins may threaten water supply

The water sample of harmful algal blooms pictured was taken from Harsha Lake in May 2012.

The water sample of harmful algal blooms pictured was taken from Harsha Lake in May 2012.
By Megan Alley
Sun staff

This summer, toxins given off by harmful algal blooms could once again threaten local water sources.

According to a presentation by Hannah Lubers, project manager for Clermont County’s Office of Environmental Quality, to Clermont County Commissioners on May 4, HABs, also known as blue green algae, are made up of cyanobacteria that contain chlorophyll and perform photosynthesis. They are known to release toxins that can attack the skin, liver and nervous system in humans and animals, said Lubers.

When the levels of microcystin, a class of toxins produced by certain freshwater cyanobacteria, reach six parts per billion, a recreational public health advisory is given. When levels reach 20 ppb, which can cause human illness and pet death, a No Contact Advisory is issued.

HABs were first detected in Harsha Lake in 2012, and the first No Contact Advisory was dispensed in 2013. Since then, HABs have been found throughout Clermont County, including East Fork, farm ponds and golf course ponds.

“We believe that once the harmful algal blooms are in a body of water, they will be there for a while,” said Paul Braasch, director of Clermont County’s Office of Environmental Quality. “The HABs turn into resting cells over the winter and grow when the conditions are favorable again.”

HABs thrive in warm, calm water with lots of sunlight. They also need access to nutrients, such as nitrogen and phosphorus, which come from the runoff carrying fertilizer applications from farms and lawns.

“The widespread impacts of HABs can negatively affect recreation, drinking water and the economy,” said Lubers.

In 2014, the regional swim meet at East Fork had to be moved because of high microcystin levels, and this year, microcsystin could threaten the national rowing championships set to take place July 14 at East Fork.

“There are some theories about why we’re seeing in increase in HABs now. Basically, changes in farming practices, different types of fertilizer, and weather are all making conditions favorable for the HABs,” said Lubers.

The East Fork Watershed Cooperative, which is made up of federal, state and local partners, is conducting research and developing solutions to remove the HABs, said Lubers.

“Short term plans such as treating the reservoir on a smaller scale with copper sulfate, alum or ferric, or reservoir mixing, aeration and dredging, are not cost effective on larger reservoirs such as Harsha Lake, so we have to look at long term solutions and solutions that prevent the HABs from blooming,” explained Lubers. “We need to look at the source of the blooms. Weather patterns and nutrients feed the blooms, and since we can’t control the weather, we’re going to look at nutrient sources.”

The watershed cooperative has received two major grants to continue its research to determine what effect reducing fertilizer runoff through best management practices would have on the HABs.

Data acquired from the watershed cooperative, which includes studies done by the U.S. EPA Office of Research and Development, show that nutrients for the HABs are coming from agricultural runoff.

“The studies go on to show that 80 percent of the nitrogen is coming from agricultural runoff and 97 percent of the phosphorus is coming from agricultural runoff,” said Lubers.