Michael Rose

Statesman Journal

Salem has added extra treatment steps to its municipal water system after a toxin produced by an algae bloom was detected in samples drawn from the North Santiam River, the city's primary source of water.

The toxin, cylindrospermopsin, was found at "barely measurable levels" in untreated river water on Aug. 1, said Francis Kessler, operations division manager for the city's public works department.

None of the toxin has been found in Salem's finished drinking water, Kessler said. The extra water treatment processes — an additional filtering step — will continue until no trace of cylindrospermopsin is found in river water, he said.

Peter Fernandez, Salem's public works director, said the city hasn't had serious problems with algae blooms.

"When we see things like this (a contaminant), we have to be very aware because we don't treat our water with a lot of chemicals," he said.

Salem uses a sand filtration method to process drinking water. It's a treatment system used by few U.S. cities and requires relatively clean raw water to be effective, Fernandez said.

Cylindrospermopsin can cause illness in people and pets with symptoms including nausea, vomiting, and diarrhea, according to the Oregon Health Authority. The toxin targets the liver and kidneys.

It's a different algae-produced toxin from the one that recently contaminated Toledo, Ohio's drinking water, called microcystin. Residents of Ohio's fourth-largest city had to avoid tap water for several days.

Earlier this month, a health advisory was issued for Devil's Lake near Lincoln City after high levels of microcystin were detected.

For four years, the city of Salem has tested for the presence of algae toxins in water taken from the North Santiam River Watershed.

Toxins have been found in Detroit Reservoir water samples in past summers, when algae blooms tend to occur.

The reservoir empties into the North Santiam River, but this is the first summer cylindrospermopsin has been found in river water by the city's testing protocol.

Water pollution and warm weather contribute to algae blooms, although the causes of the algae blooms at Detroit Reservoir aren't well understood, city officials said.

The amount of toxin found in North Santiam River water was five parts per quadrillion, far below the amount considered a health concern.

mrose@StatesmanJournal.com (503) 399-6657 or follow on Twitter @mrose_sj

Water worries

The problem: Low levels of cylindrospermopsin, a toxin produced by algae, have been found in the North Santiam River but not in Salem's tap water.

The response: Instead of pulling water straight from the river, the city is pumping water from wells and pushing it through two filtration systems before sending it on to residents.

Source: City of Salem

Detection history

The city of Salem has been closely monitoring the North Santiam River Watershed, the source of the city's drinking water. Specific tests for cyanotoxins, a variety of toxin produced by algae blooms, have occurred on a regular basis for four years.

2011: The city sampled for anatoxin-a and microcystin. There were no detections of the toxins at any of the sample locations.

2012: The city sampled for anatoxin-a, microcystin and saxitoxin. There were no detections of any toxin at any of the sample locations.

2013: The city sampled for anatoxin-a, microcystin, saxitoxin and cylindrospermopsin. There were six detections of cylindrospermopsin: Four in Detroit Reservoir and two in the upper North Santiam River just below the dams. No toxins were detected in the source water at the middle intake at Geren Island.

2014: The city sampled for anatoxin-a, microcystin, saxitoxin and cylindrospermopsin. There were 33 detections of cylindrospermopsin. Cylindrospermopsin was found in 27 samples from the Detroit Reservoir, two samples taken in the upper North Santiam River just below the dams and in four samples at the middle intake at Geren Island. None of the toxin was detected in drinking water leaving the Geren Island Water Treatment Facility and delivered into the distribution system.

Source: Lacey Goeres-Priest, water quality and treatment supervisor, city of Salem