The Oregon Health Authority on Tuesday lifted a recreational use health advisory for Fern Ridge Reservoir.

The health authority had announced the warning on June 18 in response to toxic algae blooms detected in the lake.

“Water monitoring has confirmed that the level of cyanotoxins in Fern Ridge Reservoir are below recreational guideline values for people,” Oregon Health Authority stated Tuesday in a press release.

The agency said that visitors to Fern Ridge Reservoir should continue to be alert for signs of a bloom.

“This is because blooms can develop and disappear on any water body at any time when bloom conditions are favorable,” the agency stated.

Oregon Health Authority said that only some water bodies in Oregon are monitored for algae blooms and toxins. For this reason, people should become familiar with signs of a blooms, as well as the symptoms of exposure.

The health authority said people should 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. Pets should also be kept from those areas.

The agency stated that cyanotoxins can still exist in clear water. To learn more about harmful algae blooms, visit Oregon Health Authority’s website.

Original story:

The Oregon Health Authority on Wednesday issued a recreational use advisory for Fern Ridge Reservoir, a lake west of Eugene that is popular for swimming and boating.

“The decision to issue the advisory is based on a report of a toxigenic bloom from a partner agency,” the agency stated in a press release. “Results of testing in the days to come will either confirm the advisory or allow us to lift.” 

The health authority suggested people avoid swimming, water skiing and power boating in areas of the lake where blooms are present, “as the major route of exposure is ingestion of water.” Pet owners should also prevent their dogs from drinking the water. 

The release cautioned that toxins cannot be removed by boiling, filtering or treating water with camping-style filters. 

Anglers should also avoid eating fish caught from areas where algae blooms are present. 

Exposure to cyanotoxins in algae blooms can cause a range of symptoms, including stomach cramping, diarrhea, nausea and vomiting, as well as numbness, dizziness and shortness of breath, the health authority said.

Toxins are not absorbed through the skin, according to the agency. However, people with skin sensitivities may get a puffy red rash.

According to the Centers for Disease Control and Prevention, many factors can help algal blooms grow, including high nutrient levels from fertilizer, sewage and runoff. Algae blooms also are more likely to grow in warm, slow-moving water.