Blue-green algae to become more prevalent, experts say

June 12, 2018
Blue-green algae to become more prevalent, experts say

Toxins affecting Salem’s drinking water part of a trend

By Stephen Hamway

Scientists say the toxins causing Salem’s ongoing water crisis are becoming more common and longer-lasting across Oregon’s reservoirs.

Longtime Central Oregonians are likely familiar with blue-green algae blooms, vivid green clouds caused by single-celled organisms known as cyanobacteria that spread across bodies of standing water.

Because the blooms tend to appear in warm, nutrient-rich water, they’re most common in mid- to late summer.

However, as the climate changes and Oregon’s man-made reservoirs get older, it’s likely the blooms will become common during other times of the year, according to Dr. Wayne Carmichael, emeritus professor in aquatic biology and toxicology at Wright State University in Ohio, and a board member for the Oregon Lakes Association.

“The timing for it is clearly getting earlier and earlier,” Carmichael said.

The organism that creates blue-green algae blooms — which is not technically an algae — has been around since prehistoric times, according to Rebecca Hillwig, an environmental health specialist with the state’s Harmful Algae Bloom Surveillance Program, which is operated by the Oregon Health Authority.

She said cyanobacteria tend to do well in warm, dry conditions, which other plants and animals in the water can struggle to adapt to.

“What would kill other organisms doesn’t seem to affect them as much,” Hillwig said.

While the organism requires nutrients like phosphorus and nitrogen to grow on a massive scale, Hillwig added that no one knows precisely what causes them to appear, or why some release more toxins than others.

Carmichael said climate change can be expected to cause drier winters and springs, along with long, hot summers, conditions that will contribute to warmer water conducive to algae blooms. Additionally, as the state’s dams and other man-made infrastructure age, more nutrients for the organisms will enter the reservoirs.

“It certainly adds to the situation,” Carmichael said.

Over the past 12 summers, the Oregon Health Authority has issued 14 advisories for algae blooms in Central Oregon, spanning five lakes and reservoirs in the region. Lake Billy Chinook has had advisories during each of the last three summers, and Wickiup Reservoir was affected in 2014. Haystack Reservoir, Crane Prairie Reservoir and Paulina Lake have also had advisories since 2006.

Most recently, blue-green algae has prompted a series of water quality advisories in Salem. Around Memorial Day, the city first detected elevated levels of toxins in Detroit Lake, a man-made lake near U.S. Highway 22 that provides much of Salem’s drinking water. Peter Fernandez, director of Salem’s public works department, said the city has been observing algae blooms in the lake since 2010, but noted that this was the first time his department has observed elevated toxin levels in the drinking water.

“We really don’t know what happened here,” Fernandez said.

The city issued a notice warning vulnerable populations not to drink the water on May 29. The advisory was lifted and then re-instituted after another test showed toxin levels just above the federal standards mandated by the federal Environmental Protection Agency, according to Fernandez. While recent tests have not shown elevated toxin levels, Fernandez said the city’s most recent water quality advisory will remain in effect until at least June 24, when the city hopes to introduce a new system that uses powdered activated carbon to eliminate the algae.

In Bend, much of the city’s drinking water comes from creeks and groundwater wells, and contamination from blue-green algae is less of a factor. Still, the blooms can cause problems for people and pets spending time in contaminated lakes during the summer. They can cause rashes and other types of skin irritation, as well as indigestion if swallowed. Hillwig noted that pets, which are smaller and often consume more lake water, are particularly vulnerable.

“Even if it’s safe for a child under 5 … it’s still not safe for a dog,” she said.

While the number of harmful algae advisories has not increased in recent years, Hillwig said that’s likely due to a lack of sampling and monitoring on many Oregon lakes and reservoirs.

The state received a grant from the Centers for Disease Control and Prevention to set up monitoring, but Hillwig said the grant concluded in 2013. Since then, monitoring has largely been left up to individual water managers, who often lack the money and expertise to do it effectively.

“We’re running on fumes,” she said.

—Reporter: 541-617-7818,

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An aerial view of a body of water.