The Oregon Health Authority issued a recreational health advisory on Friday, Aug. 3, alerting the public to a visual siting of harmful algae bloom in the Ross Island Lagoon. Ross Island is located on the Willamette River just south of the Ross Island Bridge, about a mile south of downtown Portland.
The state agency has taken water samples to confirm the type of cyanobacteria present and the level of potential toxins that might be produced from the algae.
The advisory is confined to the Ross Island Lagoon and its mouth, but the bloom could spread from there elsewhere into the Willamette.
The Oregon Health Authority advises people not to drink water directly from the river where toxic algae blooms are identified, and notes that dangerous toxins cannot be removed simply by boiling water. No potable water systems have been affected by the algae blooms, the agency reported.
Health officials also advise people not to swim or engage in high-speed water activities, such as water skiing, jet skiing and power boating, in areas where such blooms are identified. Toxins aren't absorbed through the skin, but people with skin sensitivities may experience a puffy red rash at the affected area.
Algae blooms can develop in areas where there is low water flow and slow-moving water, such as the lagoon.
For more information or to report an illness, contact the Oregon Health Authority at 971-673-0440.
Ross Island is partly owned by Ross Island Sand and Gravel, which mined gravel from the lagoon from 1926 to 2001. The company's base of operations is located on the riverfront just east of the island.
Ross Island Sand and Gravel is owned by Robert Pamplin Jr., who also owns the Portland Tribune and Pamplin Media Group.
There are four islands in and around Ross Island, including Toe, Hardtack and East islands. An earthen dike was constructed between Ross and Hardtack islands in 1926-27 to create the Ross Island Lagoon, according to the state Department of Environmental Quality.
Ross Island Sand and Gravel began importing fill material to replace the removed gravel beginning in 1980, according to the DEQ. Some of that fill turned out to be contaminated, and the company was required to cap the contamination with clean fill material.
The cleanup was completed in 2010, and DEQ issued a "no further action" recommendation in 2011.
To get Sustainable Life news delivered weekly to your inbox: https://bit.ly/2Isfz1F