Exposure Characterization of a Cyanobacteria Harmful Algal Bloom (CHAB) — Data Collection Methodology

1276 

Professional Poster 

S Viet¹

¹Westat, SBS, CO

Susan Viet PhD, CIH, FAIHA  
Westat

Potentially harmful freshwater algal blooms of cyanobacteria (CHAB) are increasingly reported among U.S. surface waters, (e.g., recreational and drinking waters, industrial settling ponds, fish farm ponds. A number of anecdotal reports have intimated blue-green algae as the source of respiratory illness and sometimes death in dogs and livestock exposed to CHAB infested waters. Exposure assessment has been limited and a variety of approaches have been employed. This poster presents the methodology for one study conducted at Clear Lake, CA.

Clear Lake, CA is regularly impacted by CHABs during the spring through fall seasons. As part of the USEPA's effort to characterize such exposures, air and water samples were collected adjacent to the shore at a public beach on five consecutive weekends.

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 for analysis of endotoxin, phytoplankton, cyanotoxins, phycocyanin and chlorophyll-a. Water characteristics (temperature, pH, turbidity, dissolved oxygen) and weather condition (temperature, humidity, wind direction, wind velocity, rainfall) were recorded after each sample collection period. Observations of human activities were made every hour throughout the sampling period, characterized by type of contact with water (e.g., no contact, hands/feet in water, partial submersion, full submersion, in boat, or on watercraft. The number of people engaging in each activity were counted by age group category (infants, toddlers, preadolescents, adolescents, adults). Dogs were counted due to recent reports of respiratory illness and death among dogs swimming in a CHAB infested waters.

Initial results indicate that the sampling protocols allow for quantitation of cyanotoxins and endotoxin, and associated human activity. This abstract does not necessarily reflect USEPA policy.

Exposure Assessment Strategies

Aerosols

Occupational and Environmental Epidemiology