CLEMSON – Meet the culprits that can make the region’s drinking water taste and smell foul.
In this vial, blue-green algae. In another, diatoms, the brownish algae.
They come from Lake Hartwell, and they thrive with warm weather and just the right amount of light. But on this day, they are living in a ground-level laboratory at Clemson University.
Kayla Wardlaw hunches over a microscope. She is surrounded by vials and beakers. Some of them contain algae and sediment samples from the lake. She moves away from the microscope and holds a vial up to the light. Some tiny, dark-colored creatures are still swimming in it.
Wardlaw, a graduate student studying environmental toxicology, extracts lake algae to study its pigment. She explains her mission in simple terms. She wants to know what classes of algae are present, and in what concentrations they exist.
SCIENCE OF THE LAKE
- Algae existed in Lake Hartwell at least as early as the mid-1970s, according to a report issued by the U.S. Environmental Protection Agency four decades ago.
- The algae being studied by Clemson University researchers is benthic, meaning that it grows on the bottom of the lake and is often not immediately visible.
- Researchers are studying two major groups: blue-green algae and diatoms.
Understanding Lake Hartwell is understanding the region’s main raw water source. The Anderson Regional Joint Regional Water System uses the lake to provide up to 48 million gallons of water daily to nearly 200,000 customers. A lot of water treatment happens between the lake and the tap. But if a collection of algae is thriving in the lake, the activated carbon that is added to the water in treatment processes may not be enough to keep odor-causing compounds at bay.
That’s where Wardlaw and students like her come in.
If she knows what classes of algae are present in the lake and in what concentrations they exist, that information can be used to try to keep the region’s drinking water pleasant to taste and free of odor.
WHAT’S IN THERE?
Regional water system officials reached out to Clemson University for help last September, after a spring and summer full of stinky drinking water. Led by professor John Rodgers, an expert in nuisance vegetation, researchers discovered that the source of the trouble was benthic algae, or algae that grows on the bottom of the lake and attaches itself to objects such as rocks and sticks.
“At first, we didn’t know what the problem was going to be,” Wardlaw said. “We couldn’t even see it. But when we started drawing samples from depths of the lake, we could smell it.”
The smell comes from geosmin and 2-Methylisoborneol, or MIB. Geosmin and MIB are the two algae-produced compounds that caused the unpleasant taste and odor in the region’s drinking water last year, and they are the ones that officials and researchers are trying to control this year.
Based on their research, Wardlaw and other students overseen by Rodgers have identified what they call an “assemblage” of algae that they believe to be responsible for producing the taste and odor problems. Included in the blue-green side is Oscillatoria, named for the way it can move, and Anabaena, which looks like a twisted strand of pearls. The diatoms, or brownish algae, include Fragilaria and Tabellaria.
But algae in Lake Hartwell didn’t just show up a couple of seasons ago.
Algae existed in the lake at least as early as the 1970s, according to a report issued by the U.S. Environmental Protection Agency.
WHAT HAS CHANGED?
Scott Willett, the executive director of the regional water system, has said for months that the drinking water in this part of the Upstate has remained safe, even as officials tried to rid it of taste and odor troubles.
So if the drinking water is safe and algae has been a part of Lake Hartwell for decades, why did the taste and odor problems surface with a vengeance last spring?
“There’s no exact reason that we can be sure of at this point,” Wardlaw said. “The best we have are theories. We think that part of it may have to do with lake levels. When the water was low, plant matter grew in places that are now covered by water. And the shoreline would be covered with nutrients, so you have the kinds of conditions that could allow algae to thrive.”
Conditions that led to the algae may have started in 2013, when, after a long drought, Anderson had its second-wettest year on record. In an 18-month period, Anderson got more than 94 inches of rain.
“The other thing is that there are more people living on Lake Hartwell than there were years ago,” Wardlaw said. “You have development, you have people doing lawn care, those kinds of things can affect the conditions algae need.”
When fertilizers that are used to keep lawns green run off into the lake, their nutrients can also feed algae.
So far, regional water system officials have approved one algaecide treatment on Lake Hartwell. The hydrogen peroxide-based treatment was applied to 6.5 acres of lake and shoreline around the regional water system’s intake.
Willett and the team at Clemson University expect that another, larger treatment will be applied later this week.
“The monitoring and research provided by Clemson has been instrumental in assisting the joint water system with knowing when to treat, and more importantly, how to treat,” Willett said. “Once in-lake treatment was selected as an option, the two most important aspects are timing and dose.”
Clemson University has a contract with the regional water system but does not work exclusively with that agency. This time of year, Wardlaw said, companies often are seeking help with algae problems. Requests for such help are sent to the university from a company in Georgia, she said.
Still, much of Wardlaw’s working life these days is centered on the issues faced by the regional water system. It’s why she’s out on Lake Hartwell at least twice a week right now. It’s why Rodgers laughs when he’s asked about her lab schedule.
“She lives there,” he jokes.
Back in the lab, Wardlaw returns to her microscope.
“My grandmother lives on the lake,” she said. “The water system’s drinking water is her drinking water. This is important work to everyone involved in it. We’re invested.”
Photo: By Sefton Ipock. Kayla Wardlaw, a graduate student at Clemson University, uses a microscope to look at algae in a water sample from Lake Hartwell. Wardlaw is part of a team studying the lake water in the hopes of curtailing an algal bloom similar to one that caused problems with drinking water last year.
View original article at: In the lab: Region’s water under the microscope