Why our lake?

A dense bloom of potentially toxic blue-green algae that caused county water plants to discontinue pumping water from Marion Reservoir has residents scratching their heads and wondering, “Why us?”

Algae blooms “happen periodically and by no means is this a unique situation,” according to the Kansas Department of Health and Environment, but the situation left many residents questioning just how safe the water supply really is.

Peggy Blackman, water quality coordinator for the Marion Reservoir Watershed and chair of a newly formed county task force on water quality, said she wanted to “help put the public at ease as to really what’s happening.”

“We want to inform the public that this is what they call a chronic situation,” she said. “This is not an acute situation at all. It’s not that (the algae) hasn’t been there before, it just has not been in the quantity that was quite so evident. It is the amount of the bloom and the toxin it produces that is the hazard, not just because it is there.”


Blue-green algae blooms often occur in lakes and rivers during the spring and early summer months. The anabaena species found in the Marion Reservoir is one of four types of blue-green algae capable of producing toxins.

“It releases the toxins as it dies,” Blackman said. “The only time we would ever see any great toxicity is in extreme concentrations and near the intake of a water-treatment facility.”

The effects of algae toxins are still under study. The toxins can kill livestock and pets that drink significant quantities of the bloom waters.

Although no human deaths directly related to algae blooms have been documented, the toxins are known to cause skin irritations, nausea and diarrhea in humans who drink untreated water or who swim near algal blooms.

Some algal toxins are suspected to stimulate cancer growth, and studies are currently under way to explore those risks.

Lack of standards

Blackman said the algae is not something that is routinely tested for, and it was the Hillsboro water-treatment facility that noticed and became suspicious of the elevated phosphorus levels.

Those levels, combined with the presence of the algae bloom near the water intake, aroused the concern of water-quality officials.

Because of the rarity of this type of algal bloom in Kansas and the fact there are no national or state standards related to algae toxins, it was difficult to judge how serious the problem really was.

“In our water-quality standards for the state of Kansas and the nation, this toxin has never been addressed as to what might be the safe level,” Blackman said.

The Environmental Protection Agency includes blue-green algae on its “Drinking Water Contaminant Candidate” list. This list includes contaminants that are known to occur in public water systems and require additional research, occurrence monitoring and guidance development.

“It’s been identified as one that needs study, but it isn’t the priority of certain other parameters,” said Mike Tate, chief of the technical services section of KDHE’s Bureau of Water.

He said that until standards are developed, “what people are looking at comparing is work in some other countries, primarily Australia and Canada and the World Health Organization.”

Conditions were right

Tate said the blue-green algae isn’t itself an automatic cause for alarm.

“If you took a lake sample and looked at a microscope, you’d probably find them in most lakes at most times,” he said. “What was unique about this was the density of it for the period of time when you saw the large blooms and mats of it.

“You always see algae in that lake. What you typically see are green algae which don’t produce these toxins,” he added. “Nutrients in the water is what will start any kind of algae growth, whether it be the green algae or the blue-green algae.”

Tate said the green algae tend to predominate when the ratio of nitrogen to phosphorus is at least 10. When a higher amount of phosphorus is present and the ratio of nitrogen to phosphorus drops to a lower level, the conditions are right for the blue-green algae to take over.

Water quality experts also say cooler weather, less wind and greater than normal sun penetration also contributed to making conditions perfect for algae growth.

“We have had some gorgeous water out there. It has been so pretty and blue and very clear compared to what we are used to seeing,” Blackman said. “Normally, sunlight would penetrate maybe a foot to 18 inches, and we are seeing depths of clarity as far down as three, four, five feet.

“The sunlight is penetrating it far greater than it ever has before, because we don’t have the suspended solids in the lake with the sediment that we’d normally see. That’s because we don’t have the runoff. We’ve had no significant runoff whatsoever from the tributaries coming into the watershed. We just have not had the significant rains.”

Said Tate: “What we’re surmising can be happening there is with less runoff, the water’s just being held in that lake. Normally you’d have more discharge from the lake and you’d get those (nutrients) flushing through there. With no discharge, over a period of time those nutrients have just set in there and have given the algae a chance to get a foothold.”

Nutrients in the lake

So how do these nutrients get into the lake in the first place?

Nitrogen and phosphorus can be tracked back to fertilizers and animal wastes that enter the water system.

“Phosphorus tends to bind with soil, and if you get sediment runoff it will stay bound with that soil,” Tate said. “What may be happening in this case is that some of the phosphorus that’s also in the bottom sediments of the lake could be getting released.”

Blackman said the erosion is a natural phenomena caused by natural lay of the land, type of soil, and type of farming.

“This is just the nature of the area we live in,” she said. “What our lake is experiencing is not any different from any other lake in Kansas-depending on the amount of crop land, the type of soil, and what may be surrounding that lake.

“We have a situation where our lake was placed in farm ground to begin with,” she added. “We have known through the years that our lake has had a significant amount of sedimentation coming in. That is our principal contaminating element.

“Sedimentation is the erosion of land, sediment coming in via the tributaries, off of the fields, off of our homes-anything that has erosion creates sedimentation.”

Despite the sedimentation, Marion County water is very clean, she said.

“The EPA has set a total maximum daily load of possible contaminants that may come into a water source. Our current TMDL status with the state for Marion County and Marion Reservoir in particular is moderate-not high,” Blackman said.

“Really, and I’m sincere in this, we have one of the cleaner bodies of water and cleaner tributaries in the entire state.”

Long-term solutions

That’s not to say there isn’t room for improvement, and Marion County is actively working on initiatives to improve watershed management practices, she said.

One such initiative is the 319 Water Quality Marion Reservoir Watershed project, of which Blackman is coordinator. This initiative is designed to help producers implement practices that will preserve the land’s topsoil and reduce the runoff of nutrients and other contaminants into the waterways.

Blackman said the lake was built on 70,000 acres of crop land in the reservoir watershed itself.

“Forty thousand of those acres are eroding above a tolerable level,” she said. “And so this is why we have this 319 water quality grant that I am working on in place-to help these producers put in their grass waterways, their terraces, their reseeding pastures or in taking minimal producing land and turning it into continuous CRP (Conservation Reserve Program) or CRP.

“They are finding it is just not profitable to farm that ground where they are not getting good crops and that turning it into a grassland is actually preserving what topsoil is there.

“It just takes hundreds of years to produce an inch of topsoil. We want to help the farmer and rancher be as productive as possible and also get the practices in place that are going to help them maintain that precious topsoil.”

Blackman said she is also involved with the governor’s “buffer initiative” that will also have a positive effect on lakes and other waterways by placing buffers -strips of grass, shrubs and trees-long fields, roadsides and stream banks to catch the soil and hold it rather than allowing it to go into the waters.

“We now have 30 percent more cost share available for any producer who’s wanting to come in and place these strips into their farming practice,” she said. “That will occur July 1.”

In the near-term

Obviously, these are not short-term fixes. In the meantime, county water-treatment facilities will begin treating the water with the addition of powdered activated carbon, a commonly accepted practice for treatment of algae and alga toxins.

Tate said both the Hillsboro and Marion plants already have processes in place to “settle” the water as well as filter it and that provides an extra level of defense against toxins.

“The toxins are tied up in the algae, and they typically release it when they die,” he said. “Both plants now settle those algae solids out, and as long as they don’t kill those solids in that process, they are removing a big bunch of the toxins in settling and filtering those algae cells out. Then whatever might have been released in the lake or died through the process is what the carbon works on.”

Although water officials hope the water treatment will control the situation, they are not ruling out the chance of more algae blooms down the road, perhaps yet this summer.

“It could reoccur,” Tate said. “It depends on climate, rain and everything else.”

But without standards, will it be any easier to assess the seriousness of the situation the next time around?

“We’ve learned a lot from this,” Tate said. “A bloom to this degree we had not seen before. As it was near the intake to the lake, we agreed with the cities it was probably time to stop using that if possible until we could get some more information.

“What we’re trying to do is get together some reference material that’s already been done, and based on some testing, try to come up with more of a ratio,” he said. “What people can do is count the number of cells of this algae in the lake fairly readily. It’s not expensive, and a lot of different folks can do it.”

By counting the number of algae cells in a sample, the density of the bloom could be determined, he said. With that information, water-quality officials could determine whether the toxins would be at a level significant enough to warrant discontinuing pumping the reservoir water.

“There’s a lot of good information out about the effectiveness of drinking-water treatment plants on removing these things too, and they’re pretty effective at getting rid of those toxins,” he added.

“I think everybody knows a little bit more at this time, and are working with those cities to get the treatment plants fine tuned, if you will, to be able to maximize the removal of any problem.”

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