A blue-green algae bloom in Black Lake has recently produced enough toxin to prompt a swimming advisory for the lake that is now in effect. Swimming or water-skiing in water with algae toxins or drinking it can lead to serious illness, so people and pets are advised to stay out of the water at Black Lake, and anglers are reminded that the safest bet in algae-prone waters is to catch and release.
Water samples taken from Black Lake on July 29 found the algae toxin Microcystin at 162 micrograms per liter of water—well above the state standard of 6 micrograms per liter for recreational water use. Microcystin can cause liver poisoning in people and animals. Symptoms, which include abdominal pain, diarrhea, and vomiting in humans and death in animals, can take hours or days to appear.
"We know this comes when recreational use of the lake is at its highest point of year. Anglers, boaters, water-skiers and swimmers are all using the lake right now," said Art Starry, Director of the county's Environmental Health Division. "Our advice to folks is to stay out of the lake and not take the chance of getting sick. It is especially important to keep small children and pets out of the water."
Warning signs will be posted at public access points, including Kenneydell Park, the public boat launch and the community docks across from Black Lake Grocery. The lake will be monitored weekly until the algae bloom is over and the advisory can be lifted.
While not all algae blooms are toxic, some algae can produce toxins that can harm the nervous system, the liver, the skin, and the stomach and intestines. Experts from the county's Environmental Health Division recommend a few simple tips to help prevent illness from algae:
WHAT: Toxic Algae Advisory for Black Lake
- Avoid swimming, wading, wind surfing and water-skiing in waters where algae blooms are present.
- Don't drink untreated surface water.
- Keep pets and livestock out of waters with algae blooms.
- When fishing, catch-and-release is the safest practice. If you do eat your catch, clean any fish you catch thoroughly if you see algae blooms. Before eating, remove the internal organs, which may contain harmful algae toxins.
- Avoid areas of scum when boating and clean your boat thoroughly.
- No swimming, no pets, no fishing advised
The health advisory is in effect for all of Black Lake
- Kenneydell Park is located at 6745 Fairview Road SW in Olympia, 98512
- Public boat launch is located at 7107 Fairview Road SW in Olympia, 98512
For more information about toxic algae blooms and other water quality information, visit the Thurston County Environmental Health web pages at www.co.thurston.wa.us/health/ehadm/swimming/swimming_index.html