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Sonoma County issues toxic algae warning for Russian River beaches

The Press Democrat - 7/26/2017

July 26--Sonoma County officials were planning Wednesday to post beaches up and down the Russian River with caution signs alerting visitors to positive test results for a potentially dangerous naturally occurring neurotoxin linked to harmful algae that is plaguing other Northern California waterways this summer.

Water samples collected at three local beaches turned up very low levels of a substance called Anatoxin-a, which is produced by certain species of blue-green algae, Sonoma County health officials said.

The samples were taken Monday and the test results received Wednesday, Deputy County Health Officer Karen Holbrook said.

Though the level of toxin in the water "was just at the ability to detect it," the finding triggers precautions under state guidelines, she said.

River-goers should be particularly watchful of dogs, which are actually attracted to harmful algae, according to studies, and, by virtue of their relative body size and habits when around fresh water, are particularly susceptible to exposure.

But swimmers, waders, tubers, paddle-boarders and others who may have direct contact with water, as well as parents of small children, should take precautions to ensure they do not put themselves or their offspring at risk, health officials said.

That means avoiding ingesting river water or cooking with it, washing off after swimming, and avoiding hand-mouth contact.

"Be aware and take precautions to protect themselves, particularly their pets, but also know that the river is open," Holbrook said.

The warning comes after a broader alert from North Coast Regional Water Quality Control Board about the potential for harmful algal blooms in fresh water bodies around the region -- including Lake, Mendocino and Humboldt counties -- due to summer conditions that including warming water temperatures and still water.

Sonoma County health officials and state quality water regulators have been monitoring conditions in the Russian River closely since an outbreak of harmful algae the summer of 2015 led to the deaths of two dogs. In both cases, Anatoxin-a appeared to be responsible, causing violent, sudden illness and death within moments of exposure.

Caution signs were posted against last year on the Russian River after routine testing revealed low levels of the substance.

Seasonal testing began again last week after river monitoring revealed the kinds of conditions in which blue-green algae, or cyanobacteria, thrive, Holbrook said.

All 10 beaches that are part of the testing protocol were clear last week.

But test results received Wednesday showed that samples from Cloverdale River Park Beach, Del Rio Woods Beach in Healdsburg and Patterson Point beach, downstream of Monte Rio off Villa Grande, all had barely detectable levels of Anatoxin-a, roughly one-tenth of a microgram per liter, Holbrook said.

Under state guidelines, any detection of neurotoxin triggers cautionary notification about a water body.

Warnings that prohibit swimming and other activities in the water are not required until the toxin level reaches 20 micrograms per liter.

The bilingual caution signs going up Wednesday say that harmful algae "may be present" in the water and urge the public to avoid algae and scum while swimming, to keep children away from the shoreline, to prevent animals from drinking the water or eating scum, to avoid drinking or cooking with the water, to throw away the guts and clean fillet of any fish caught in the river and to avoid eating shellfish caught in the river.

Potentially harmful blooms have been reported at several sites around Northern California already this year, including Clear Lake and Upper and Lower Blue Lakes, both in Lake County. Toxic concentrations of two harmful algae also were detected in a Napa River pond where two pet dogs died last month.

You can reach Staff Writer Mary Callahan at 707-521-5249 or mary.callahan@pressdemocrat.com. On Twitter @MaryCallahanB.

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