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. Exposure to the toxins can cause symptoms similar to food poisoning, such as stomach cramping, or worse, the state agency said.

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, which is sourced from the North Santiam River, 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.

The history of the 2018 Salem water crisis

An algae bloom discovered in Detroit Lake in May 2018 sent cyanotoxin levels in the North Santiam River above EPA health advisory levels. The levels put young children, pets, pregnant and nursing people, and those with weakened immune systems at potential risk.

The crisis triggered a shortage of bottled water in the region and caused weeks of uncertainty.

The event spurred the city to invest in a $48 million, state-of-the-art ozone treatment facility at Geren Island.

In the summer, the community uses about 55 million gallons of water per day, according to city data. That amount decreases to about 20 million gallons a day in the winter.

Ozone is considered one of the strongest disinfectants used for treating drinking water — even stronger than chlorine. It is used nationally, including in Oregon in Lake Oswego, Medford and Wilsonville.

City officials called the ozone treatment a "robust, long-term insurance policy against cyanotoxins" and well as helping the city adapt to wildfire runoff and heavy rains.

The ozone treatment went online in the summer of 2021.

Symptoms of exposure to cyanotoxins

Exposure to cyanotoxins can be serious and cause a range of symptoms including stomach cramping, diarrhea, nausea and vomiting, OHA said.

"Symptoms may also be more serious, such as numbness, tingling, dizziness and shortness of breath. These symptoms may require medical attention," OHA said.

Dogs can experience weakness, difficulty walking, seizures, lethargy, loss of appetite and more. If a dog exhibits symptoms, veterinary treatment should be sought as quickly as possible.

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."

OHA recommends not eating fish from area with cyanobacteria

Fish caught from areas where cyanobacteria blooms are present may pose unknown health risks, so OHA recommended not eating fish from those areas.

"Those who decide to eat the fish should remove fat, skin and organs before cooking or freezing. Toxins are more likely to collect in these tissues. Fillets should also be rinsed with clean water," OHA said.

Reporters Zach Urness and Whitney Woodworth contributed to this story.

This article originally appeared on Salem Statesman Journal: Health officials warn public to avoid North Santiam River due to cyanotoxins