Toxic algae blooms detected at Offut Lake, Lake Lawrence, Thurston County warns
Thurston County is warning the public to avoid Offut Lake and Lake Lawrence due to toxic algae blooms.
Staff from the Environmental Health Division of the county’s Public Health and Social Services Department took water samples from Offut Lake on Oct. 22 and Lake Lawrence on Oct. 21. The county then issued advisories last week.
Lab results detected microcystin toxin levels at 41.7 micrograms per liter in the Offut Lake sample. Meanwhile, the Lake Lawrence sample showed microcystin toxin levels at 10.9 µg/L. Both levels are above the state recreational threshold of 8 µg/L. Microsystins are a group of toxins that affect the liver and are possible human carcinogens, according to a county news release.
People who contact water with high levels of microcystin can develop gastrointestinal illness such as vomiting and diarrhea and suffer liver damage, according to the county’s website.
Staff plan to collect and test one water sample a week until toxin levels fall below the regulatory guideline for two consecutive weeks. Only then will the advisory be lifted.
Until then, the county advises the public not to drink or touch the lake water even if it appears visibly clear of algae. That means no swimming, wading, wind surfing or water-skiing. Pets and livestock should also be kept away from the lake.
Additionally, the county advises the public to not eat any fish that come from the lake during the algae bloom and to avoid areas of scum when boating.
Offut Lake is east of Old Highway 99 in the center of the county. The lake spans 191.2 acres and contains populations of rainbow trout, cutthroat trout, largemouth bass, yellow perch, and brown bullhead catfish, according to the Washington Department of Fish and Wildlife.
Lake Lawrence is south of Yelm on the eastern side of the county. It is 326.5 acres and features populations of largemouth bass, yellow perch, bluegill sunfish, pumpkinseed sunfish, brown bullhead catfish, and stocked channel catfish, according to WDFW.
Notably, the county issued an algae bloom advisory for Pattison Lake earlier this month that remains in place. On Oct. 14, the county indicated that microcystin toxin levels were at 17.4 µg/L in sample taken Oct. 7.
Current lake advisories and more information about algae blooms can be found on the Thurston County PHSS website.
