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Click on the buttons below to find resources and data relating to cyanotoxins in Clear Lake. Explore the map below to view the latest cyanotoxin levels measured at sites around Clear Lake.    During the summer season we take water quality samples every two weeks at each of our shoreline or interior of the lake sites.  Results are posted once we received them.  All Result Values are microcystin cyanotoxin unless otherwise noted.

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The Big Valley Environmental Protection Department (Big Valley EPA) researches, plans, funds, and implements projects that protect the Tribe's natural resources. These activities also benefit non-Tribal residents and visitors to Lake County, as well as researchers, state and local governments, and other Tribes that may be facing similar challenges. This page contains information on cyanobacterial blooms that happen in Clear Lake and surrounding creeks.

Clear Lake and surrounding creeks, like many water bodies statewide, can contain cyanobacteria. Cyanobacteria are a natural part of aquatic ecosystems but when certain conditions are favorable, they can grow rapidly, causing blooms. Cyanobacterial blooms can impact other aquatic organisms, wildlife, people, pets, and domestic animals. Some impacts are caused by cyanotoxins produced by cyanobacteria that can affect skin, the liver, or the nervous system. Some cyanobacterial blooms appear as discolored water or scum or mats on the surface or along the shoreline. Other blooms may be less visible within the water column, along the bottom, or attached to aquatic plants. You cannot tell if toxins are being produced by looking at the bloom. Practice healthy water habitats to protect yourself, your family, and your pets.

The Big Valley Band of Pomo Indians began a cyanobacteria and cyanotoxin monitoring program on Clear Lake in 2014 with another shoreline Tribe, Elem Indian Colony. Together the two Tribes' Environmental Departments have collaborated with equipment, resources and time to test the water for toxins produced by cyanobacteria. The visible blooms began to be a regular presence on the lake in 2009, and the California Office of Environmental Health Hazard Assessment (OEHHA) recommended monitoring in 2012. The Tribes stepped in to do this work to protect the lake, the Tribal citizens, and residents and visitors to the lake.  Since 2021, Big Valley has continued the monitoring program on its own.

Sites with more than 1 toxin tested are marked by a circle with a diamond shape in it.  The color of that marker is dependent on highest toxin level analyzed.  Click on the marker to see toxin results for each site. 

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