Health officials warn public to avoid North Santiam River due to cyanotoxins

The Oregon Health Authority said Tuesday evening that people should avoid getting in the North Santiam River due to the presence of cyanotoxins.

OHA issued a healthy advisory for the North Santiam River from the confluence with the South Santiam River up to the mouth of the Little North Fork Santiam River in Mehama and a precautionary advisory for the North Santiam River from Mehama upstream to and including Big Cliff Reservoir and Detroit Reservoir.

"People should avoid swimming and high-speed water activities, such as water skiing or power boating, in areas of the river and reservoirs where blooms are present, as the major route of exposure is ingestion of water," OHA said.

The city of Salem said testing of water from the North Santiam River going through its Geren Island Water Treatment Plant shows it is safe to drink.

OHA said drinking water directly from areas of the river and reservoirs affected by an algae boom is "especially dangerous."

Toxins cannot be removed by boiling, filtering or treating water with camping-style filters.

OHA said campers along the river should contact campground managers or local health departments with questions about water at nearby campgrounds or day use areas.

The agency also said people who do not use a well or public water system and draw in-home water directly from an affected area should an alternative water source.

City of Salem says drinking water is safe

The city of Salem issued a statement soon after the OHA advisory was issued saying Salem's drinking water remains safe.

The city in 2021 completed new filtration systems, ozone treatment, and chlorination processesat the water treatment facility at Geren Island on the North Santiam River.

The facility screens water from the river and sends it through slow sand filters and then through a chamber where ozone made from super-cooled liquid oxygen turned into gas dissolves in the water and destroys cyanotoxins. It also breaks down other materials that can make the water look, taste or smell off.

"The Geren Island Water Treatment Facility continues to safeguard Salem’s drinking water from cyanotoxins," the city said in a prepared statement.

OHA warns about increased risk of exposure for children and pets

OHA's advisory said children and pets are at increased risk for exposure to cyanotoxins because of their size and level of activity.

"Dogs can get extremely ill and even die within minutes to hours of exposure to cyanotoxins by drinking the water, licking their fur or eating the toxins from floating mats or dried crust along the shore," OHA said.

"Intoxication is a potentially fatal disturbance in brain function resulting from an imbalance of electrolytes in the body," the advisory said. "Water intoxication and heat stroke can cause similar symptoms as exposure to cyanotoxins."