Follow-Up Test Detects No Microcystins in Wilsonville, Sherwood Water Supply

Samples of local water delivered to a Seattle-area laboratory for testing on Friday, June 1, revealed no detectable level of microcystins in the local water supply, the cities of Wilsonville and Sherwood announced today.

A ‘non-detect’ result was returned this morning for three samples – source water, finished water and distributed water – supplied by the City of Wilsonville.

As an additional measure to ensure the health of the water supply, Wilsonville is sending samples to two laboratories to analyze seven straight days (June 1-7) of water.

***June 13, 2018, update: all samples analyzed by laboratories during the week of June 1-7 returned 'non-detect' results, indicating no cyanotoxins in the Wilsonville/Sherwood water.***

Additionally, the California lab handling the Willamette Water Treatment Plant’s EPA-guided testing under the Unregulated Contaminants Monitoring Rule (UCMR4) delivered a promising preliminary follow-up report on the sample that initially detected microcystins. The “Algal Low 9” test, which analyzes eight variants of microcystins and nodularin, returned non-detect for all nine variants this morning.

On Thursday, May 31, Wilsonville learned that a UCMR4 sample detected 0.34 µg/L, slightly over the EPA’s guideline value for microcystins—one of the four cyanotoxins of greatest concern in drinking water.

For more information on Wilsonville water, visit www.ci.wilsonville.or.us. For general questions about water quality, people can visit the Oregon Health Authority’s website or call 2-1-1 for more information.

Bill Evans, Communications and Marketing Manager
503-570-1502; evans@ci.wilsonville.or.us