Willamette River Health Advisory in Portland Expanded Due to Toxic Algae

Several samples were collected around Ross Island, but the specific sample used for this count was from the mouth of the Ross Island lagoon.

(PORTLAND, Ore. ) — The Oregon Health Authority is expanding a health advisory after preliminary test results show blue-green algae covering a stretch of the Willamette River flowing through downtown Portland is a toxic species.

Officials with OHA's Public Health Division say the advisory, first issued September 16 for the stretch of the Willamette between the south end of Ross Island and the Fremont Bridge, now extends from Ross Island downriver to the south end of Sauvie Island.

Public health officials recommend that people avoid all contact with Willamette River water in this stretch of the river, and that pets be kept away from the water as well. This includes avoiding swallowing or inhaling water droplets, and avoiding skin contact. Drinking water directly from this stretch of the Willamette is especially dangerous at this time.

The public will be alerted when the concern no longer exists.

Official results of at least two tests on water samples conducted by the Oregon Department of Environmental Quality are expected back later Friday. A preliminary test by one of the laboratories, Aquatic Scientific Resource, confirmed the blue-green algae, which is visible as a swirling, bright-green slick, is a species known as Microcystis aeruginosa (microcystis). This type of algae produces toxins that are harmful to humans and animals.

The advisory threshold for microcystis is 40,000 cells of the toxin per milliliter of water. Preliminary counts indicate microcystis is present in the Willamette River at 2.25 million cells per milliliter. Several samples were collected around Ross Island, but the specific sample used for this count was from the mouth of the Ross Island lagoon.

Accidental swallowing of water containing these toxins may produce such symptoms as numbness, tingling, dizziness, weakness, diarrhea, nausea, cramps and fainting. Inhalation of water droplets can lead to breathing problems, sneezing, coughing or runny nose. Skin contact can cause skin irritation, including a rash. Symptoms usually occur in less than 24 hours.

Children and pets are at increased risk for exposure because of their size and level of activity. Dogs, in particular, can quickly experience symptoms of microcystis exposure and can die within an hour.

The toxins produced by microcystis cannot be removed by boiling, filtering or treating the water with camping-style filters, health officials warn. People who draw in-home water directly from Willamette are advised to use an alternative water source because private treatment systems are not proven effective at removing algae toxins.

No public drinking water systems draw water from the portion of the Willamette River affected by the health advisory.

Oregon health officials recommend that people who choose to eat fish from waters where algae blooms are present remove all fat, skin and organs before cooking, because toxins are more likely to collect in these tissues.

Public health officials also advise that people not eat freshwater clams or mussels from affected water, and that Oregon Department of Fish and Wildlife regulations do not allow the harvest of these shellfish from freshwater sources. Crayfish muscle can be eaten, but internal organs and liquid fat should be discarded.

For local information about water quality or blue-green algae sampling, contact the Department of Environmental Quality at 503-693-5723.

Source: Oregon Health Authority