Exposure Characterization of a Cyanobacteria Harmful Algal Bloom (CHAB) at Clear Lake, CA: Data Collection Methodology

Potentially harmful freshwater algal blooms of cyanobacteria (CHAB) are increasingly reported among US surface waters. Clear Lake in Lake County, CA is regularly impacted by CHABs during the spring through fall. As part of the US Environmental Protection Agency (EPA)’s effort to characterize CHAB exposures, air and water samples were collected at a pier adjacent to the shore at a public beach on five consecutive weekends during September-October, 2017. Air samples were collected for eight hours at 4-5 LPM; 20 Button samplers with fiberglass filters were collected in duplicate for endotoxin analysis; 20 closed-face, 25-mm MCE filters were collected in replicate for cyanotoxin analysis. Water samples were collected three times during each sampling day. A bucket was dropped from the pier to collect surface water from the top 10 inches; individual samples for analysis were collected from the bucket sample. Water samples were submitted to laboratories for analysis of endotoxin, phytoplankton, cyanotoxins...