UPDATE: Lab results from an algal bloom taken at Pattison Lake on 09/19/2023 detected Microcystin at 7.5 ug/L which is below the regulatory limit of 8ug/l. Anatoxins were detected BELOW regulatory limits of 1ug/l. With two weeks of consecutive sampling below advisory levels, the public health advisory has been LIFTED.

Thurston County Public Health and Social Services is reporting a toxic algae bloom at Pattison Lake. Lab results show toxin levels of Microcystins at the sample site at Lake Pattison Lake are 40 ug/L and Anatoxins > below method detection limit. The state advisory level for Microcystins is 8.0 ug/L and 1.0 ug/L for Anatoxin.

Microcystins are a liver toxin and possible human carcinogen. Microcystins can also cause illness in livestock and pets that drink affected water. Staff will collect weekly samples until the algae bloom clears. Warning signs are posted at the boat launch. 

When an algae bloom is present, health officials recommend taking extra precautions to avoid the health risks posed by potential toxins.

• Do not drink the lake water.
• Avoid contact with water containing algae.
• Avoid swimming, wading, wind surfing and water-skiing in waterbodies where algae blooms are present.
• Keep pets and livestock away from where algae blooms are present.
• Do not eat fish that come from the lake during an algae bloom.
• Avoid areas of scum when boating. 

For more information about toxic algae blooms and health risks, visit: www.thurstoncountywa.gov/departments/public-health-and-social-services/environmental-health/water/water-recreation