What triggers a Do-Not-Drink advisory?
If test results show health advisory levels of cyanotoxins after treatment, the Oregon Health Authority requires a second water sample—called a confirmation sample—be taken the following day at the same location. The follow-up sample—the second part of a two-part test—is taken because health issues related to cyanotoxins are based on multiple day exposure to the toxin at concentrations above the advisory level. The results of the two-step test—initial and confirmation sample together—provide the critical information needed on the presence of cyanotoxins and how long it has been present.
Where are the samples tested?
We have our own U.S. Environmental Protection Agency-preferred water testing system, ELISA, which means test results are available sooner than if they need to be sent to another lab. If an initial result shows the presence of cyanotoxins at concentrations above the health advisory level, our staff can draw a confirmation sample as soon as possible the following day (right after midnight) and run the lab test overnight. This allows us to tell the community as soon as possible if there is a need to issue a Do-Not-Drink advisory. We post results on our website during the algal season (May 1-October 31).
What happens if cyanotoxin test results indicate the need for a Do-Not-Drink health advisory?
If cyanotoxin test results indicate the need for a Do-Not-Drink health advisory, our community and water customers will be notified through our emergency notification system, news media, and social media channels.
How will water users learn more about the potential public health issues?
We will be coordinating with the Oregon Health Authority, Marion County Environmental Services, and Oregon Department of Agriculture to provide residents and businesses the best available information on potential public health issues and steps our community can take to keep their family and pets safe. We will use the same process to let people know when our water is safe again to drink following an advisory.
The U.S. Environmental Protection Agency also has public health information on their website.
How is a Do-Not-Drink advisory lifted?
To lift a Do-Not-Drink advisory, test results must meet the Oregon Health Authority requirements of two consecutive days of sampling that show cyanotoxins at concentrations below the health advisory levels. We will also consider other factors such as cyanotoxin levels in the watershed when deciding to lift a Do-Not-Drink advisory.
What are the new rules?
The Oregon Health Authority requires us to test and to report results for two cyanotoxins produced by cyanobacteria (algae). Based on national public health research shown in the U.S. Environmental Protection Agency guidelines, the rules set two health advisory levels for cyanotoxins in drinking water—one for "vulnerable people" and one for "all persons." A health advisory level is the concentration of cyanotoxins at or below which adverse health effects are not expected to occur if consuming water containing cyanotoxins at this level for up to 10 days.
|Healthy Advisory Level||Vulnerable People||All Persons|
|Who is Affected||Children under the age of six, pregnant women or nursing mothers, and those with pre-existing liver conditions of receiving dialysis treatment||Everyone|
|Total Microcystins Trigger||0.3 ppb||1.6 ppb|
|Cylindrospermopsin Trigger ||0.7 ppb||3 ppb|
Is there a health advisory level for pets?
There is no health advisory level for pets. The U.S. Environmental Protect Agency reports cyanotoxins can be harmful to animals if they drink tap water contaminated with elevated levels of cyanotoxins. They advise pet owners to contact a veterinarian if animals show signs of illness.