Monday October 13, 2025
Tri-City Herald —
Despite cooling temperatures, toxic algae continues to be found in the Columbia River in the Tri-Cities and nearby in the Snake River.
The most recent water samples collected by the Benton Franklin Health District found toxins at levels dangerous to animals and people at the Leslie Groves swim beach on the Columbia River in Richland.
All other checks of the Columbia River in the Tri-Cities found no toxin levels of concern.
However, the health district said river currents can change quickly and move floating algae debris along the shorelines.
“Be cautious if you see floating algal mats in the river,” it said.
Signs have been posted at Leslie Groves Park warning that playing in the water there could make people and pets sick. Six dogs are known to have died since 2021 after wading in contaminated water along the shore of the Columbia River in the Tri-Cities area when toxic algae was present.
The Washington state Department of Ecology is also warning of toxic algae on the Snake River, including at Charbonneau Park.
It is 15 miles east of the Tri-Cities in Walla Walla County via Highway 124.
The toxin released by bacteria in the scum in slow-moving river water at Leslie Grove Park is anatoxin-a and the toxin on the Snake River is microsystin, both of which can kill dogs.
Dogs can be exposed to the poisons if they drink the water, lick their fur after being in the water or being sprayed with the water or eat algae clumps.
Dogs that develop symptoms need immediate veterinary care and people with symptoms also should get medical care.
Symptoms of anatoxin-a, which attacks the nervous system, can appear within 15 to 20 minutes, depending on the size of the person or animal and the amount of toxins consumed.
Exposure in animals may result in weakness, staggering, difficulty breathing, convulsions and death.
In people, signs may include numbness of the lips, tingling in fingers and toes, and dizziness.
Symptoms of microsystin poisoning may take hours to days to appear.
They include abdominal pain, diarrhea, vomiting and a skin rash in humans. Initial symptoms in dogs are lethargy, vomiting and diarrhea.
People catching fish in areas with a major toxic algae bloom, should be aware that the neurotoxin may accumulate in the liver, kidneys and other organs of fish. They should remove the skin, fat and internal organs, which may contain more of the neurotoxin, or consider not eating the fish.