Toxic algae warning expanded for Oregon's Willamette River

By Courtney Sherwood PORTLAND Ore. (Reuters) - Tests have confirmed that a green film shimmering on the surface of the Willamette River as it flows through Oregon's largest city is caused by toxic algae that can be dangerous to people and animals, public health officials said on Friday. Authorities also expanded the "warning zone" issued on Wednesday when the algae was first observed, declaring water recreation unsafe for the hundreds of boaters and swimmers who normally use the river daily at this time of year. Tests completed on Friday showed the blue-green algae known as microcystis is present at 50 times the maximum safe level, the Oregon Health Authority said in a press release. The notice warned the public to avoid all contact with a 10-mile stretch of the Willamette, which runs through downtown Portland and is fringed by industry, parks, marinas and housing. Swallowing or inhaling water contaminated by the algae can cause numbness, digestive distress or fainting, and skin contact can cause a rash. Filtering the water will not make it safe, and fish or shellfish from the river could be dangerous to eat, the health authority said. Dogs are particularly vulnerable, and can die within an hour of contact, according to the agency. Toxic algae blooms have been a growing problem in the U.S. Pacific Northwest during the past several years, a trend scientists attribute to warming waters. But previous outbreaks have been mostly confined to ponds and lakes. Health authority spokesman John Modie said that unusually high temperatures in Portland may have allowed the algae to form in the relatively stagnant waters of a river lagoon before spreading to the Willamette's more swiftly flowing main channel. He declined to speculate on how long the algae will remain, saying it could take days or months to dissipate. (Reporting by Courtney Sherwood in Portland; Editing by Steve Gorman and Sandra Maler)