Cyanobacteria are naturally present in bodies of water worldwide. But with excess nutrients, typically in warm months, they multiply and bloom, and can produce liver toxins, neurotoxins, or toxins that can cause gastrointestinal illness. Such harmful algal blooms become public health concerns.
In a recently published study, Theo Dreher, professor emeritus of microbiology at Oregon State University, analyzed the toxic bacteria in Detroit Lake over time. That included 2018, when toxins caused do-not-drink notices for at-risk populations in Salem, which gets its drinking water downstream from the reservoir. Genetic analysis found that the predominant type of toxin shifted in about 2018.
“What we've contributed is to identify the two toxin producers and to show that they were the ones over the entire period from 2011 to 2024,” Dreher told KLCC. “So there aren't any unknowns there, which is comforting.”
However, said Dreher, the bacteria strain that’s currently dominant lives longer, so harmful blooms may contaminate Detroit Lake for more days, each year.
A trio of harmful cyanotoxin, or blue-green algae, events in 2017 and 2018 led the Oregon legislature to fund the Oregon DEQ and Oregon Health Authority to beef up the research and analysis of cyanotoxins.
Dreher said the state now has good tracking, monitoring and public health safety tools. The new research would allow water utilities to target genetic testing for specific bacteria.
What the public should know, said Dreher, is to avoid scummy water, and especially to keep children and dogs away. Pets often lick their fur to clean themselves, ingesting harmful toxins, which can be deadly.
