A health advisory was issued on Tuesday for Cullaby Lake due to a bloom of harmful algae.
State public health officials confirmed the presence of cyanobacteria and the toxins they produce at the popular recreational site off U.S. Highway 101 near Warrenton. A similar bloom occurred at Coffenbury Lake in Fort Stevens State Park last summer.
Officials say people should avoid swimming and high-speed water activities in areas where blooms are identified.
Drinking the tainted water is especially dangerous. The toxins cannot be removed by boiling, filtering or treating the water.
The bloom is the second recorded at Cullaby Lake within the past five or six years, said Steve Meshke, natural resources manager for Clatsop County. Other times, toxin levels have neared the threshold.
He began keeping an eye on potential blooms and taking water samples as awareness has grown about the danger the toxins present.
The lake and surrounding parkland are popular with boaters and large groups. The park may host as many as 400 or 500 people on a busy weekend day. On Tuesday, Meshke saw between 30 and 40 people at the park.
Boating is still safe on the lake so long as speeds don’t create excessive water spray, which could lead to inhalation risk.
If people choose to eat fish they catch from the lake, they should first remove all fat, skin and organs before cooking since toxins are more likely to collect in these tissues. Fillets should be rinsed with clean water.
The toxins cannot be absorbed through the skin, but people who have skin sensitivities may experience a puffy, red rash.
Pets and children are at increased risk for exposure because of their smaller size and activity levels.
Exposure to the toxins can produce a number of symptoms, including numbness, tingling and dizziness that can lead to difficulty breathing or heart problems. People may also experience skin irritation, weakness, diarrhea, nausea, cramps and fainting and should seek medical attention if these conditions persist or worsen, public health officials say.
Public health officials say cyanobacteria is not always obvious and toxins can still exist in clear water. Sometimes affected water will also look foamy or scummy.