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Harmful algae prompts health warnings at multiple Portland-area lakes

Lacamas Lake and Round Lake are both under health warnings due to the presence of cyanotoxins, which can be harmful to people, especially children, and pets.

VANCOUVER, Wash. — Clark County Public Health issued a warning Thursday for high levels of cyanotoxins and cyanobacteria at Round Lake near Camas, after issuing a similar warning last week for the nearby Lacamas Lake.

The Oregon Health Authority has issued similar warnings for cyanobacteria or another toxin called microcystin at multiple swimming sites around the state, including the Willamette River at Cathedral Park in Portland as of Wednesday.

Water samples taken Monday at Round Lake showed cyanotoxins levels beyond the safe limit recommended by the Washington Department of Health, county officials said in a press release. 

RELATED: Health advisory: No swimming, water skiing at Lacamas Lake

Warning signs are being placed at public access points around the lake. Officials will monitor both lakes and take weekly water samples to test for toxins when algae blooms are present.

Cyanotoxins are produced by harmful algae, and can rise to unsafe levels during algae blooms. The toxins can be harmful for people, especially children, and deadly for pets if they drink the water.

“Our pets, especially our dogs are really susceptible to these cyanotoxins because they tend to swallow more water,” said Curtis Cude with the Oregon Health Authority. “A lower level of cyanotoxins can actually be potentially deadly to our dogs.”

Cyanobacteria can cause wheezing, coughing, chest tightness and shortness of breath if inhaled and abdominal pain, diarrhea, vomiting and dizziness if ingested, according to Clark County health officials, and skin contact can cause rashes, itching, blisters or eye irritation.

RELATED: Henry Hagg Lake tests negative for toxic algae bloom

While the advisory is in effect, officials recommend that people avoid swimming or water skiing and don't let their pets have any contact with the water. Boaters and kayakers are advised to steer clear of areas with visible scum or algae.

“The conditions are improving for cyanobacteria blooms to flourish and last longer,” said Aaron Borisenko, a water quality monitoring manager for the Oregon Department of Environmental Quality, which tested water samples from Cathedral Park.

Borisenko said that as more people learn to recognize the harmful blooms, more are getting reported to health authorities. However, he believes the increase is also tied to climate change.

“The factors that climate change favors, like warming water temperature, are favorable to the formation of bloom.”

Borisenko along with the Oregon Health Authority further discussed the issue of cyanobacteria and harmful algal blooms in this recent edition of the DEQ’s GreenState Podcast.

Officials began monitoring Lacamas Lake in July and had to issue a cyanotoxin warning for a few weeks, but were able to lift it as water quality improved. New tests last week prompted it to be re-issued.

Vancouver Lake was also placed under a cyanotoxin warning back in June, although it has since been lifted. A harmful algae bloom is still being monitored by officials at the lake, however, according to Clark County's database.

Clark County's map and list of cyanotoxin warnings can be found here. The Oregon Health Authority's list of advisories can be found here.

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