Monitoring our drinking water for cyanotoxins
- About this page:
- Last Updated: July 12, 2018 July 12, 2018
Cyanobacteria, sometimes called blue-green algae, are microscopic organisms found naturally in all types of water: fresh, brackish (combined salt and fresh water), and ocean water. These organisms use sunlight to make their own food. When present in large numbers, they may form visible green, blue-green or reddish-brown blooms that float on the surface of the water.
Not all blue-green algae blooms produce toxins, but under certain conditions, such as in warm water containing an abundance of nutrients, they can rapidly form harmful algae blooms capable of producing toxins known as cyanotoxins that can harm humans and animals. For more information on cyanotoxins, visit the Environmental Protection Agency’s website on cyanobacteria.
Photo courtesy of Oregon Health Authority
Salem’s health advisory
The City of Salem regularly samples for cyanotoxins in Detroit Reservoir, the North Santiam River, and at their drinking water treatment plant. On June 6, 2018, Salem issued a health advisory for their drinking water specifically targeting vulnerable customers such as children under the age of 6, those with compromised immune systems, and others. This health advisory was issued after more than one sample showed the presence of cyanotoxins in Salem’s drinking water after treatment. The health advisory continued for some time. More information is available at https://www.cityofsalem.net/water-advisory.
Albany’s drinking water
Albany has sampled for the same cyanotoxins as Salem and to date has found no presence of cyanotoxins in any treated drinking water. Because the Albany-Millersburg Water Treatment Plant takes in raw water from the main stem of the Santiam River downstream of Salem’s intake, Albany was asked to monitor for cyanotoxins. Samples have been taken weekly beginning May 30 at the intake on the main stem of the Santiam River and as treated drinking water leaves the treatment plant. While we have detected low levels of cyanotoxins at the raw water intake, none has been detected in the treated drinking water.
The Albany-Millersburg plant is one of two drinking water treatment plants in Albany. The other is the historic Vine Street plant which only takes water from the South Santiam River. Samples for the Vine Street Plant were also taken on May 30 as a precaution. Weekly samples of the Vine Street plant will be taken from July 2 through the end of the summer.
Albany will continue to monitor for cyanotoxins through the summer of 2018. Samples will be taken weekly at both drinking water plants. Results will be posted on this website as they are available.
Are cyanotoxins in drinking water currently regulated?
At the time of Salem’s initial health advisory, state and federal authorities did not require drinking water providers to monitor or treat for cyanotoxins. While blooms of cyanobacteria have become more common in recent years, neither the Environmental Protection Agency (EPA) nor the Oregon Health Authority (OHA) have developed regulations on cyanotoxins. As a result, most drinking water providers did not routinely sample for these substances in the past. Blooms of cyanobacteria in Detroit Reservoir, upstream of the City of Salem’s drinking water intake, in 2015 led Salem to begin routine monitoring in the reservoir. Until this year, cyanotoxin had never been detected in Salem’s treated drinking water.
Detecting cyanotoxins at the drinking water intake and in the treated water in Salem led to OHA requesting other drinking water systems to test their intakes and treated drinking water for the substances. Advisory levels have been developed by the EPA, but the EPA has not issued regulations for cyanotoxins. In response to the 2018 event, OHA developed and published temporary rules for drinking water providers in Oregon regarding cyanobacteria and cyanotoxins. These temporary rules are available on the OHA website.
The EPA is considering developing rules for cyanotoxins under the Safe Drinking Water Act. Albany will be sampling for cyanotoxins as part of the EPA’s fourth Unregulated Contaminant Monitoring Rule program over the next two years. For more information on this rule, visit the EPA’s website.