Diarrhetic Shellfish Toxin Closes Beach In South Puget Sound For First Time

Jul 24, 2013

Wednesday the Department of Health closed some shellfish beds in South Puget Sound for the first time due to elevated levels of Diarrhetic Shellfish toxin.The biotoxin made 3 people sick after eating mussels harvested in Sequim Bay in 2011.

Scientists at the Washington Department of Health Lab in Shoreline test shellfish for toxins that come from harmful algal blooms.
Credit Ashley Ahearn / KUOW

It was the first time anyone had been officially diagnosed with Diarrhetic Shellfish Poisoning in the United States, and the biotoxin which can cause diarrhea and vomiting appears to be spreading in Puget Sound.

At the Department of Health lab in Shoreline a group of scientists stare at a mass spectrometer.

The machine is set up to detect toxins in samples of shellfish that come in from all over the Washington shoreline.

Right now the scientists are waiting for the machine to tell them if the toxin that causes diarrhetic shellfish poisoning is in a sample of mussels taken near Olympia in Budd Inlet.

The levels on the screen spike above the safe limit.

Jerry Borchert oversees the monitoring and shellfish bed closures for the Washington Department of Health.

“It’ll be the first area in the South part of Puget Sound where we’ve had a DSP closure and what worries me is is this the only one or might there be more" says Borchert.

The southern part of Puget Sound is a big shellfish farming area.

DSP and other forms of shellfish poisoning happen when certain types of algal blooms release a toxin that then gets sucked up by filter feeders like mussels and clams.

The blooms occur naturally and are strongest in the summer and early fall, though scientists don’t fully understand what makes the algae release the toxin.

This week the Department of Health has closed some shellfish beds in San Juan, Thurston, King and Jefferson counties because of elevated levels of shellfish toxins.

And just a reminder, cooking or freezing shellfish won’t get rid of the toxins.

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