Cyanotoxin Sample Collection Considerations

In EPA’s webpage Determination of Cyanotoxins in Drinking and Ambient Freshwater, there are three primary considerations for sample collection.

The bottle type, volume, and any preservatives will depend on the laboratory doing the analysis. Sample containers will be borosilicate glass or PTEG plastic to avoid potential cyanotoxin adsorption. Amber glass will minimize toxin sample degradation from sunlight exposure, but clear bottles can be wrapped in aluminum foil. Check early with your chosen laboratory(s) to see what you may need and if they can provide the supplies to you.
Chlorinated samples may require “quenching” immediately upon sampling. This is very common with “finished” drinking water samples. Sodium thiosulfate and ascorbic acid are the most common quenching agents. The type of toxin being tested and the method being used will determine which agent is required as they are not interchangeable.
It is critical to chill samples immediately after collection and maintain cold temperatures (around 10^o C) during shipping and holding times at the lab. It may be appropriate to freeze toxin samples to extend holding times. If freezing is necessary, make sure to allow head space to avoid bottle breakage. Ask the laboratory about freezing samples when you contact them.

Some cyanotoxin detection methods may require having the cyanobacterial cells “lysed.” Lysing causes the bacterial cells to rupture and release any toxin that was inside the cell walls. Some mechanisms such as freezing and thawing the samples have been used, but it may not be sufficient to lyse all the cells. Make sure to find out from the laboratory if lysing is necessary and the best method to lyse the cells.

The need to have a quicker and more conclusive method to identify toxins is behind the movement by surface water programs and water body managers from using microscopic identification to qPCR. qPCR will check for not only the presence and density of cyanobacteria cells but also quantifies the presence of any cyanotoxin-producing genes. While it can be a more expensive method, it has the advantage of a quicker analysis and a more conclusive determination if toxins may be present. This can help drinking water operators to determine if and when to start testing their raw and/or finished water and to narrow down what type of cyanotoxin(s) to test for.

Cyanotoxin sampling. Photo courtesy of the Idaho Department of Environmental Quality.

Finally, who is monitoring the health of your source water? You can check with your regional DEQ office or your DEQ Compliance Officer to find out what kind of testing is being done on your source water body. Depending on the water body, groups from governmental agencies (federal, state, and local), water body managers, non-profit organizations, environmental groups, and private companies, may be doing regular water testing near or upstream of your intake. Knowing this information can help in sampling coordination, quicker response to incidents, and creating community education opportunities.

Next month's topic

Potential Indicators of Cyanobacteria Presence in Source Water

Regional HAB Advisory News

There are three advisories in the Northwest currently. A permanent advisory has been established for Anatoxin-a in the South Umpqua River, Oregon. In Washington, there are advisories for Anderson Lake and Wiser Lake.

Resources

Previous Idaho Drinking Water HAB Newsletters can be found at the Idaho DEQ website page: Cyanobacteria Harmful Algal Blooms.

Communicating During an Emergency: Cyanotoxin Lessons From Oregon – Association of State and Territorial Health Officials – Recorded podcast from October 8, 2020, discussing when the City of Salem detected cyanotoxin in their drinking water in 2018 (21:27 minutes)

Learn to Identify Cyanotoxin Blooms - ITRC video (33:38 minutes)

Cyanotoxins: A Guidance Document for Public Health Laboratories – Association of Public Health Laboratories (APHL)

Monitoring Tool from the Strategies for Preventing and Managing Benthic Harmful Cyanobacterial Blooms - Interstate Technology and Regulatory Council (ITRC)

Guidance for Responding to Drinking Water Contamination Incidents - EPA

Learn about Cyanobacteria and Cyanotoxins - EPA

Idaho Department of Environmental Quality https://www.deq.idaho.gov/