Cyanotoxin levels ‘are below recreational guideline values,’ the Oregon Health Authority says

By Morgan Rothborne, Ashland.news 

Water samples from Emigrant Lake have tested negative for illness-associated toxins common to cyanotoxin algal blooms, the Oregon Health Authority said.

“Water monitoring has confirmed that the level of cyanotoxins in Emigrant Lake are below recreational guideline values,” an OHA news release said. 

The OHA has lifted its recreational advisory for Emigrant Lake — but the public should remain cautious with all bodies of water throughout the summer, said Dr. David Farrer, a public health toxicologist with the OHA. 

Advisory followed procedure, OHA says 

The presumptive positive recreational advisory issued May 1 was normal procedure for monitoring recreational bodies of water statewide, Farrer said. A member of the public had reported seeing what looked like a cyanotoxin algal bloom in Emigrant Lake to the OHA. 

“We have access to satellite imagery for this. … The pigments specific to this cyanotoxin algae can be seen from space,” Farrer said. 

With a bloom presumptively confirmed by satellite, the OHA issued a presumptive positive recreation advisory to the public and notified its “downstream partners,” such as the Oregon Department of Agriculture, the Department of Environmental Quality and county authorities. But the recreational advisories are issued to give people information to protect themselves prior to testing. The presence of the algae doesn’t mean toxins are in the water, Farrer said. 

“If the algae are releasing the toxins, that’s the key,” he said. 

Testing samples collected May 6

Upon being notified, DEQ collected samples on May 6 to be taken to the department’s lab in Hillsboro, where the water is tested for the presence of bacteria known to cause illness, Farrer said. 

The Oregon Department of Agriculture responded to a request for comment by deferring to the OHA to answer questions, with the exception of an inquiry into whether any animals could be confirmed as harmed by algal toxins via irrigation water. 

“Toxicity in livestock is not reportable to the Oregon Department of Agriculture unless it is a large undiagnosed mortality event. We do not have any way to track and report HAB (harmful algal bloom) toxicities in livestock or other animals,” Andrea Cantu-Schomus, an Agriculture Department spokeswoman wrote in a Thursday email. 

Jonathan Modie​, a communications officer for the OHA Public Health Division, said the OHA covers recreational use and drinking water but that irrigation water would likely be the purview of the ODA or Jackson County. Dylan Darling, a public information officer for DEQ, confirmed that the department is testing the water but largely deferred questions to the OHA. 

Talent Irrigation Board President Mike Winters provided a statement to the Rogue Valley Times Friday, saying that professionals in the field should be science-based in their approach as well as responsible and responsive to water contamination concerns to ensure the retention of the public’s trust. 

“There’s nothing more important to the Talent Irrigation District than its patrons and their animals. If the professionals believe there is a problem, then take the proper samples, expedite the testing and give the irrigation district the appropriate instructions to protect our patrons and their livestock,” he said. 

Why was there a bloom so early in the year? 

Upon learning that Emigrant Lake had been at low levels for the previous eight years, Farrer said that could help create a bloom. Cyanotoxin algae come from bacteria that can rest in sediment like “seeds,” he said, and if sediment is exposed for a long time it can allow nutrients for that bacteria to develop. 

“If all those nutrients are there to feed the bacteria, a sudden influx of water could rehydrate those ‘seeds,’ he said. 

Public advised to stay vigilant 

The OHA sometimes receives reports from around the state that dogs — and in a case last year in southeastern Oregon, cattle — have been killed by suspected exposure to the toxins, Farrer said. Drinking vessels for livestock can and do develop cyanotoxin algae, he said. Not every body of water in the state is regularly tested and the algae blooms are commonly seen throughout the state during warm weather. 

“We’ve had dogs die from drinking out of a puddle,” he said. “The bacteria are microscopic, they don’t need a lot of water to thrive.”  

The photosynthesising blue-green pigments that give blue-green algae its name are distinctive, and the OHA recommends learning to identify it for safe recreation akin to the way Oregonians learn to spot and avoid poison oak. 

“Avoid areas where the water is foamy, scummy, thick like paint, pea-green or blue-green, or if thick brownish-red mats are visible or bright green clumps are suspended in the water,” the Friday OHA release advised. 

The toxins can sometimes be present in clear water as well, the release said. 

“When a bloom dies, toxins released may reach into clear water around the bloom. Blooms can be pushed into other areas, leaving toxins behind. There also are species of cyanobacteria that anchor themselves at the bottom of a water body, live in the sediment, or can grow on aquatic plants and release toxins into clear water,” the release said. 

Greater risk for dogs and small children

Dogs and small children are at the highest risk. Dogs can be attracted to the smell of the bacteria and may lap at pockets of stagnant water around lakes. And dogs and children may be likely to play in water, Modie said. During a recreation use advisory, those most at risk should be watched carefully, and high-speed water sports should be avoided. Jet-skiing or boating can result in accidentally ingested water spray or a person falling in and swallowing water. 

Though the results are currently negative, cyanotoxin algae can disperse, return and necessitate additional advisories, Modie said. 

Further algal blooms will trigger additional advisories and rounds of testing as needed through the warm weather months when these blooms are most likely, Farrer said. 

On the drinking-water side of OHA’s monitoring, those providing water — such as Ashland Public Works — test their raw water every other week. After a positive result, treated water is tested and, if positive, the public is notified while the water system responds to the bacteria. 

For health information or to report an illness, contact the OHA at 971-673-0482, or visit OHA’s website. For information on the city of Ashland’s drinking water and its source in the Reeder Reservoir, visit the city’s website. 

Email Ashland.news reporter Morgan Rothborne at [email protected].