No toxins found, but experts still advise caution
Local biologist Natalie Day has lived in Moab for the past 12 years, and she regularly visits Ken’s Lake for a swim—up to three or four times a week over this past summer. She was there in late August, walking over to where she usually starts her laps, when she noticed concerning symptoms in the water.
“I just glanced down at the water and was like, ‘that does not look normal,’” she said. “It looked like a paint spill—like a bluish-green paint spill.”
That’s a common manifestation of cyanobacteria, sometimes also called blue-green algae; some types can produce toxins that are harmful to humans and animals. Day recognized it right away—she studies cyanobacteria for her job.
“This is what I do at work all the time,” she said.
A week or so later, the Southeast Utah Health Department investigated and confirmed the presence of a potentially harmful cyanobacteria in Ken’s Lake. Tests for toxicity came back negative, but experts say these blooms are not well understood; the one in Ken’s Lake could have produced toxins before samples were taken and could still generate toxins.
A Sept. 6 warning issued by the department recommends that people avoid ingesting the water; use caution when swimming or paddling; keep pets and livestock away from the lake; wash hands with clean water before eating or preparing food; and thoroughly clean any fish harvested from the lake.
Cyanobacteria, toxic algal bloom, blue-green algae… What is it?
Salt and fresh water bodies all over the world carry small organisms that, under the right conditions, can grow exponentially. Some of these are actual algae; others are actually bacteria, though rapid growths of these organisms are all captured under the broad term “harmful algal bloom.” The concerning growth in Ken’s Lake, like most that occur in freshwater, is actually a cyanobacteria that photosynthesizes like a plant. There are many types of these cyanobacteria; factors such as temperature and nutrient concentration can trigger them to multiply rapidly, forming visible colonies that can look like swirls of paint, pea soup, or grass clippings, or form mats or globs. This is called a “bloom.” These colonies can disrupt the aquatic ecosystem, blocking sunlight or causing oxygen depletion in the water. Sometimes these blooms can also produce toxins that can damage the kidneys, liver, or neurologic systems of people or animals.
These blooms should not be confused with other types of algae, such as filamentous green algae—which, Day said, Ken’s Lake regulars may recognize as the scummy growth that often gives the water a greenish tinge in late summer. Filamentous green algae may be icky, but it doesn’t carry health risks to humans.
Cyanobacteria confirmed in Ken’s Lake
On the afternoon when she noticed the bloom, Day ran into some acquaintances, including Moab resident Katie Grauel, enjoying the lake with their dogs. Day pointed out the bacteria colony and warned her friends of the health risks of harmful algal blooms. She also emailed the San Juan County health department about the bloom, but said she didn’t get a response. (San Juan Public Health later posted a message on their Facebook page sharing the Southeast Utah Health Department notice.)
Grauel remembered Day’s warning when her dog, Pickles, got sick the night after visiting the lake. After Pickles vomited a couple of times, Grauel called the vet and described the symptoms; though he was throwing up, Pickles’s energy level was normal, so the vet believed it was likely not a serious illness. That night, though, Pickles began drinking water excessively, and Grauel started to worry. She took him to the vet the next day; blood tests showed he had acute renal injury. Veterinarians put Pickles on intravenous fluids for two days.
When Day heard about Grauel’s dog a few days later, she got in touch with Orion Rogers, Environmental Health Director at the Southeast Utah Health Department, to share her concerns. It’s not entirely certain whether the cyanobacteria made Pickles sick, but the coincidence was enough to make both Grauel and Day suspect that to be the case.
Rogers visited the lake, found the unusual scum, and took photos and samples; he sent the photos to a state water quality specialist in Salt Lake City, who agreed that the growth looked suspicious. Rogers sent Ken’s Lake water samples to two labs: one identified the genus of the bacteria as limnoraphis, which can produce toxins; the other screened for toxins and did not detect any.
Meanwhile, even before the results came back, the health department placed warning signs around the lake and issued a press release about the suspected bloom. Other agencies that co-manage the lake also shared the message: the Bureau of Land Management, which oversees recreation and the campground next to the lake, posted the warning on its Facebook page; the Grand Water and Sewer Service Agency, which manages irrigation water in the valley, linked to the statement on its website.
The concentrations of cyanobacteria found in Ken’s Lake were relatively low: over 200,000 cells per milliliter in the sample tested for species. For comparison, Rogers said the threshold of concern is 100,000 cells per milliliter; Scofield Reservoir, he said, sometimes tests as high as 90 million cells per milliliter. However, concentrations can change rapidly.
Dr. Ben Abbott is a professor of Environmental Science and Sustainability at Brigham Young University, and he has studied cyanobacteria extensively, particularly in Utah Lake. He pointed out that algal blooms follow an exponential model.
“Concentration of cells can change really fast,” he said. “You can go from two hundred thousand to ninety million in a matter of hours or days.” He added that cyanobacteria don’t always, or constantly, produce toxins, and it’s not well-understood what triggers them to do so—some theorize that the toxins may be defense against other competing algae or small grazing organisms eating the blooms.
Conversely, there could be toxins in the water even if algae is not visible. In August, the Daily Herald reported the death of a pet dog after he was exposed to toxins in Utah Lake. The owner of the dog said the water looked clear.
Cyanotoxin illnesses
Though tests for toxins in Ken’s Lake came back negative, health officials still advise caution around the reservoir; it’s possible that the cyanobacteria may still generate toxins this season.
According to the Centers for Disease Control, cyanotoxins can cause a range of symptoms in people: touching or swimming in contaminated water, or breathing in tiny droplets, can cause irritation in the eyes, nose, throat, or lungs, or on the skin. Swallowing contaminated water or eating contaminated food can cause stomach pain, headache, neurological symptoms like muscle weakness or dizziness, vomiting, diarrhea, or liver damage. The Utah Division of Water Quality also mentions kidney damage as a potential result of consumption of cyanotoxins.
“The biggest concern is generally for dogs,” Rogers said, because they’re more likely than humans to drink a substantial amount of lake water and to splash and play in areas where algae is evident; it’s best to keep pets away from the lake. Rogers said the health department has alerted local vet clinics of the risk. He added that livestock owners who use Ken’s Lake to fill their stock tanks may consider switching to an uncontaminated water source. All mammals are susceptible to cyanotoxins, including wildlife; birds and fish can also be harmed.
Ken’s Lake is used for irrigation throughout the valley. Rogers said there’s no known risk to continuing that use, except for instances where water is sprayed onto fruits and vegetables that will be consumed. Agricultural workers should also avoid exposure to irrigation water contaminated with cyanotoxins.
More frequent, more severe
Harmful algal blooms are occurring more frequently and with greater severity across the world. Utah Lake is notorious for them, Rogers said, and he posts warnings about them at Scofield Reservoir every summer.
“It blooms every year,” Rogers said of Scofield, which is in Carbon County, also under the jurisdiction of the Southeast Utah Health Department. “Hopefully Ken’s Lake doesn’t follow suit.”
Rogers added that Ken’s Lake isn’t typical of water bodies that host harmful algal blooms. It’s relatively deep and cold, he said, and it’s not a terminal lake—the water is constantly refreshed as it’s let out for irrigation and refilled from Mill Creek. As far as Rogers is aware, this is the first incidence of a suspected toxic bloom at Ken’s.
“That’s why it hasn’t been on anybody’s radar,” he said.
Abbott thinks it’s likely that there have been algal blooms in Ken’s Lake in the past, but that they’ve gone undetected. In years when the lake shrinks to an unappealing pond by late summer, it’s less likely that someone would have noticed and reported a bloom.
Abbott also suggested a potential explanation for this year’s bloom. One known trigger of harmful algal blooms is eutrophication, or an excess of nutrients, in a water body. Sources of nutrients include natural organic matter. In a high water year like this one, snowmelt-swollen streams may have picked up a large accumulation of that organic matter as they rushed down to the valley. When the water slows down in Ken’s Lake, those nutrients could get deposited and build up in the reservoir.
Abbott said the main source of eutrophication in water bodies across the globe is from agricultural runoff. Over 70 percent of the earth’s surface has been modified by people, he said, mostly for agricultural purposes.
“Thankfully, that provides food security for the global population,” he said, but added that monitoring and regulation of fertilizer use is critical to reducing eutrophication, an underrecognized form of pollution.
Other sources of eutrophication include urban waste water runoff, nitrogen-fixing crops like soy, alfalfa, and peas, and the burning of fossil fuels.
“When we burn oil, and especially when we burn coal, there’s not just carbon in there,” Abbott said. There are also nitrogen and phosphorus compounds—those are the two nutrients most closely associated with algal blooms.
“If it’s oil, it came from ancient algae, and if it’s coal, it came from ancient land plants,” Abbott said, and those nutrient-rich compounds are released and can accumulate in water and soils. He said that about two thirds of the world’s freshwater ecosystems are experiencing eutrophication.
Warmer temperatures are also associated with harmful algal blooms, and climate change is likely a factor in their increase in frequency and severity worldwide.
Once a bloom is detected, there aren’t a lot of options for decontaminating the water. Abbott said there are steps people can take to reduce the occurrence of algal blooms. More monitoring and regulation of fertilizer applications could help; higher standards for wastewater treatment could also help. Abbott said improving wastewater treatment in Utah Valley has actually improved conditions in Utah Lake since a few decades ago, when algal blooms were an even bigger problem.
“We definitely need to up our game in terms of how we grow our food and how we design our cities,” Abbott said.
Meanwhile, people should learn to recognize harmful algal blooms and report them to public health authorities when they see them. There are photo references on the Utah Division of Water Quality’s website with information on how to identify them. Rogers said that as of September 12, there were still visible cyanobacteria colonies at Ken’s Lake, looking like “fibrous pieces of grass.”
The Division of Water Quality has sent testing kits to the Southeast Utah Health Department; Rogers plans to test again for cell counts and toxicity this week and next week. If toxins are detected or cell counts increase, the current healthwatch could be raised to a warning or danger alert; the healthwatch will remain until HAB levels drop below a minimum threshold.
Pickles on the mend
Pickles the dog is still being treated for kidney injury. Grauel said that with another round of intravenous fluids and a regimen of subcutaneous fluid injections, his blood tests showed a small improvement in kidney performance, though they’re still not functioning normally. Aside from excessive water consumption and urination and occasional vomiting, he’s been behaving like a normal, healthy dog: whining to go out and exercise and waving his white tail high when trotting down the trail with a bouncy step. Grauel likes to take him on trails close to water so he can satisfy his outsized thirst. But they won’t be going back to Ken’s Lake any time soon.
