Oregon Health Authority issued a recreational use health advisory today for Ross Island Lagoon and the Holgate Channel in the Willamette River in Portland due to the presence of a cyanobacteria bloom and cyanotoxins above recreational use values for human exposure. These waters are in Multnomah County.
People should avoid swimming and high-speed water activities, such as water skiing or power boating, in areas of the river where blooms are, as the major route of exposure is ingestion of water. Toxins are not absorbed through the skin. However, if you have skin sensitivities you may get a puffy red rash.
You are encouraged to visit the Ross Island Lagoon and Holgate Channel in the Willamette River and enjoy activities such as fishing, walking, biking, canoeing, kayaking, and bird watching. Boating is safe as long as speeds do not create excessive water spray. Sprays could lead to the risk of inhaling cyanotoxins.
Drinking water
Drinking water directly from areas of the river affected by a bloom is especially dangerous. Toxins cannot be removed by boiling, filtering, or treating water with camping-style filters. Contact the local health department with questions about water available at nearby areas.
Children and pets
Children and pets are at increased risk for exposure 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. This is regardless of a recreational use health advisory in place.
Be aware that dogs can become ill and die from water intoxication after drinking excessive amounts of water while swimming or fetching objects for long periods. Intoxication is a potentially fatal disturbance in brain function resulting from an imbalance of electrolytes in the body. Water intoxication and heat stroke can cause similar symptoms as exposure to cyanotoxins.
Symptoms
Exposure to cyanotoxins can be serious and cause a range of symptoms. Symptoms may be similar to food poisoning such as stomach cramping, diarrhea, nausea and vomiting. Symptoms may also be more serious, such as numbness, tingling, dizziness, and shortness of breath. These symptoms may require medical attention. Dogs can experience weakness, difficulty walking, seizures, lethargy, loss of appetite, and more. If your dog exhibits symptoms veterinary treatment should be sought as quickly as possible.
Fishing
Fish caught from areas where cyanobacteria blooms are present may pose unknown health risks. Fat, skin, and organs should be removed before cooking or freezing. Toxins are more likely to collect in these tissues. Fillets should also be rinsed with clean water.