The City of Wilsonville learned on afternoon of May 31 that a treated water sample recently tested for contaminants revealed trace levels microcystin (micro-sys-tin), a cyanotoxin (sigh-an-o-toxin) produced by what is commonly referred to as blue-green algae. Out of an abundance of caution, the City is notifying the public of the trace detection; at this time, this is not a public-health advisory, but rather a notice of detection.

On June 1, out of an abundance of caution, the City issue a public notice of the contaminant finding, and then reached-out to communicate with commercial retailers, daycare centers, senior/assisted-living facilities, and others.

The City has rushed a sample to a laboratory in Seattle on June 1 for more thorough testing; results are expected on June 4.  Based on the result of the test, the City can determine if a public advisory is necessary pursuant to state and federal guidelines. The Environmental Protection Agency strongly recommends obtaining results from a confirmation sample prior to issuing a public advisory.

If necessary, the public advisory would likely apply to anyone who is under the age of six, who has a compromised immune system, who is receiving dialysis treatment, who has a pre-existing liver condition, who is pregnant or nursing, or who has other sensitivity concerns.

Other Resources

• Oregon Health Authorty - Cyanotoxins in Drinking Water - Frequently Asked Questions
• Oregon Health Authorty - Harmful Algae Bloom FAQs
• U.S. Environmental Protection Agency (EPA) - Cyanotoxins in Drinking Water

FAQs About Wilsonville water situation

What’s the issue with our water?

The City has detected trace amounts of microcystin (micro-sys-tin), a cyanotoxin (sigh-an-o-toxin) produced by a kind of cyanobacteria that is commonly called “blue-green algae.”  At this time, the City has issued a notice of detection and not a public-health advisory.

How concerned should I be?

The test show levels are not at a level for a public health advisory, and if an advisory is issued, the issue of concern would pertain to children under age 6 and those who are pregnant or nursing, receiving dialysis treatment, or have a compromised immune system, a pre-existing liver condition, or other sensitivity concerns.

What is the City doing about it?

Wilsonville has a state-of-the-art treatment plant that utilizes ozonation, (oh-zoh-nation), a practice deemed by the EPA to be very effective at destroying micro-organisms and pollutants through the infusion of ozone.  As a precaution, the City has adjusted ozone levels. The City has rushed a water sample to Seattle for further testing, and results are expected Monday.  Based on the result of the test, the City will determine if a public advisory is necessary.

At what levels do cyanotoxins in drinking water become a health concern?

There are no federal standards for cyanotoxins in drinking water, but other states and countries have developed drinking water standards and guidelines for various cyanotoxins. Oregon has adopted provisional health-based guideline values for the four cyanotoxins of greatest concern in our drinking water. The four cyanotoxins are: anatoxin-a, cylindrospermopsin, microcystins and saxitoxins. Microcystins and saxitoxins are two classes of cyanotoxins that each include several variations. In cases where microcystins or saxitoxins occur, Oregon Health Authority (OHA) Drinking Water Services (DWS) recommends measuring total microcystins or total saxitoxins before comparing the sample value against the provisional guideline values

Can I wash my food with water?

The level of microcystin is above the drinking water guideline value for children age 5 and under and you should not use it to wash, prepare or cook your food. Bottled water is recommended for food preparation.

What about my pets?

Dogs are especially sensitive to cyanotoxins. The Harmful Algae Bloom Surveillance (HABS) Program has a brochure on animal health and cyanotoxins available online: Animal Safety Alert - Blue Green Algae Blooms (pdf). For additional information, contact the HABS Program.

What about bathing, showering and brushing my teeth?

Cyanotoxins do not easily enter the body through the skin. Bathing, swimming, showering and brushing teeth with water is safe as long as you avoid swallowing the water. Supervise small children when bathing, swimming, or brushing teeth to ensure that they do not accidentally swallow the water.

What about washing dishes, utensils and food preparation areas?

Only a very small amount of water clings to smooth surfaces. Water can be safely used to wash and sanitize dishes, tables and eating utensils.

What about general cleaning and laundry?

Very little water remains on washed surfaces and in laundered fabrics. Because these articles are not placed in the mouth, water can be safely used for general cleaning and washing of clothing, bedding and linens.

Can I irrigate or water my garden or crops?

Water can be used for irrigation as long as precautions are taken to make sure no children or animals drink the irrigation water. Allow food crops to dry completely in sunlight before harvesting and eating it.