Aug. 19, 2016 update:
Tacoma-Pierce County Health Department received laboratory results from a Lake Tapps toxic algae sample earlier today, and the sample showed no detectable concentrations of toxin.
“The Health Department has not been able to confirm the presence of toxins in the water, nor the presence of new algal blooms, so our advisory will change to a caution,” said Brad Harp, water program resources manager.
The caution advisory lets people know that because toxic algae poses a possible health concern, they should avoid areas where visible algae may be present.
“The message we have for the public is simple: if you see algae in the water, people and their pets should stay out,” said Harp. “Although the illnesses people have reported are consistent with symptoms of toxic algae exposure, we do not believe the conditions that would further threaten public health are widely present. Again, when in doubt, stay out.”
Tacoma-Pierce County Health Department continues to monitor the presence of algae in the lake and may retest as soon as early next week.
The Health Department has not found toxic algae in Lake Tapps previously. Various conditions influence whether toxic algae produces toxins.
The people who reported illnesses described symptoms that are consistent with ingestion of microcystin, a toxin produced by several genera of cyanobacteria, including Oscillatoria. The illnesses occurred in people ages two to 48 years. Twelve people reported illnesses from swimming over the weekend, and two more reported illness over the past two days after swimming in the lake on Aug. 16 and 17. Those who reported illness recovered within a few days.
Typical laboratory tests can’t confirm that illness in people is caused by toxic algae. For more information on toxic algae, please visit our website at www.tpchd.org/toxic-algae or call (253) 798-6470.
About Tacoma-Pierce County Health Department: Tacoma-Pierce County Health Department’s mission is to protect and improve the health of all people and places in Pierce County. As part of our mission, the Health Department tackles known and emerging health risks through policy, programs and treatment in order to protect public health. We are one of only 134 accredited health departments in the country and among five in the state to have met or exceeded the Public Health Accreditation Board’s quality standards. Learn more at www.tpchd.org.
Original Aug. 18, 2016 post:
Posting lakes for toxic algae is common. Illness reports from people that could be linked to toxic algae is rare. After receiving about a dozen illness reports from people who swam at Lake Tapps last weekend, Tacoma-Pierce County Health Department found toxic algae present at the lake.
In the abundance of caution, the Health Department is urging people to stay out of the lake. People should not swim, wade or fish at Lake Tapps, and they should keep their pets from going in the water.
“We are investigating the potential link between the toxic algae bloom and the symptoms people have reported, but there is no definitive laboratory test for toxic algae illness,” Brad Harp, water resources program manager.
The Health Department has not found toxic algae in Lake Tapps previously.
The people who were sick reported symptoms that are consistent with ingestion of microcystin, a toxin produced by several genera of cyanobacteria, including Oscillatoria. The illnesses occurred in people ages 2 to 48 years, all of whom recovered within 48 hours.
Symptoms of microcystin ingestion through recreational water exposure is usually self-limiting gastrointestinal illness. Skin and mucous membrane irritation may also be present. In high doses, microcystin is toxic to the liver.
Swallowing lake water or prolonged skin contact with algae may result in illness such as muscle weakness, vomiting, diarrhea and/or nausea in people. Anyone who swallows water that may contain algae should contact his or her medical provider. Toxic algae can potentially be deadly for pets.
Diagnosis of microcystin intoxication is based on symptoms and a history of exposure to water with blue-green algal bloom. Supportive treatment includes replacement of fluid and electrolytes lost through vomiting and diarrhea. Severe microcystin poisoning causes hypovolemic shock, hypoglycemia, hyperkalemia, and intrahepatic hemorrhage. In extreme cases, death can occur within 24 hours of exposure.
Excessive nutrients from fertilizers, animal and human waste can run off into lakes and contribute to algae growth. Reducing use of fertilizers, properly maintaining septic systems, and properly disposing of pet waste helps improve water quality in lakes, streams, groundwater, and Puget Sound.