New Tests Show Increase In Toxic Algae In Lake Burien; Arbor Lake Okay

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Looks like the Creature from the B-Town Lagoon might be back folks – Miller/Walker Creek Steward Dennis Clark says that the most recent tests for toxic algae in Lake Burien shows a dramatic increase.

According to Clark’s report, a Sept. 21st sampling from a different part of the lake shows algae at 698.0 micrograms per liter, up from the Sept. 14th results of 2.68 micrograms per liter – a very dramatic increase.

However, the most recent sampling was done at the northeast outlet to the lake, in an area that contained “thick algae scum.”

Clark still recommends that lake users should keep small children and pets out of the water, as well as to avoid areas with algae scum.

Here’s what Clark had to say about this news:

It remains very important for Lake Burien users to avoid the algae scums.

The microcystin (toxicity) result from the September 21 sample of algae at Lake Burien was 698.0 micrograms per liter.  These are final, confirmed results.

I observed the collection of the September 21 sample at the northeast outlet to the lake.  The sample contained thick algae scum.  We should assume that any other algae concentrations in the lake may have similarly high concentrations of microcystin.

Although the latest results represent a dramatic change from the September 14 results of 2.68 micrograms per liter, the September 14 results were of clear lake water.

My provisional recommendations based on my discussion with Ecology staff – until I hear otherwise from my County colleagues – is that lake users should continue to avoid algae scums.  People should continue to keep small children and dogs out of the water so they do not inadvertently ingest algae. Older children and adults should follow all the guidelines in the summary sheet posted here.

Clearly, the lake is still producing toxic algae even if concentrations in the water column are below the state recommended “caution level” of 6.0 micrograms per liter. Next week, we may sample both any scums found AND clear water to quantify the relationship between the toxin concentrations in the different types of samples.

Clark also did similar tests at Arbor Lake, and here’s what he found there:

Your readers may be interested to know that I also found algae scum at Arbor Lake on September 21.  l had that scum sampled for microcystin (the toxin in the algae) as well.  Although microcystin was present, it was at the very low level of 0.096 micrograms per liter (far below the 6.0 micrograms per liter state recommended “caution level”).

Also regarding Arbor Lake, last night (Thursday, Sept. 23rd), Steve Roemer from Burien Parks, Recreation and Cultural Services held a meeting at Arbor Lake Park with neighbors to learn about their concerns and desires for park management now that the park is part of the city of Burien.  About 30 neighbors came out for this meeting.  Sgt. Henry McLaughlin from the Sheriff’s Office and I also participated.  I thought it was a productive meeting because the neighbors have a long history with their park and had many practical ideas for improving it over time.  I was impressed at how they were quick to recognize the challenges of balancing multiple goals: recreation, public safety, ecological health.  They also listened to each other and occasionally offered constructive criticism for each other’s ideas.  Not every community meeting is marked by those dynamics!  The residents were very complimentary about improvements in police responsiveness in recent years that have made the park safer and reduced the level of unsavory activities.  Neighbors also were pleased with the increase in maintenance in recent months following the annexation to Burien.  In my role as the Miller/Walker Creeks basin steward, I benefited by getting answers to a lot of questions I had about how the lake functions.  The meeting ended with several neighbors expressing hope that the city will take advantage of their high level of community interest to work together to improve the park.  Nice!

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