Investigation of Sea-to-Air Transfer in Lakes: Testing HAB Particle Aerosolization Tank Methodology

Raymond Leibensperger III1, Cassandra Gaston2, Kimberly J. Popendorf3, Brian K Haus4, Larry E Brand5, Milan Curcic6, Albert Ortiz1 and Mr. Michael Sheridan7, (1)University of Miami, Miami, United States, (2)University of Miami, Department of Atmospheric Sciences, Miami, FL, United States, (3)University of Miami, Rosenstiel School, Department of Ocean Sciences, Miami, United States, (4)University of Miami, Rosenstiel School of Marine, Atmospheric, and Earth Science, Miami, FL, United States, (5)University of Miami, Marine Biology and Ecology, United States, (6)University of Washington, Miami, United States, (7)University of Miami, Coral Gables, United States
Abstract:
Due to recent increasing frequencies of Harmful Algal Blooms (HABs), there has been increased interest in studying the effects of these HAB events and their associated toxins on humans living near the affected areas, particularly in Florida. This is important to study as HABs occur more frequently in inland fresh water sources like lakes, rivers, and canals. The impacts of toxins on seafood and water quality have been investigated, but the direct exposure through aerosolization of HAB toxins from infected waters has not been well-studied. While previous studies have attempted to mimic this aerosolization process, their techniques lacked realistic bubble generation. The goal of this project was to better understand the water-to-air transfer of these toxins using more efficient bubble generation methods. Two tanks were set up to increase toxin aerosolization and mimic realistic bubble generation in lake waters. While one tank closely mimicked wave-break zones in lakes, the other used plunging-jets and a recirculation system to produce defined bubble size distribution which recreates conditions similar to a fountain in a canal or lake. Some proposed HAB mitigation strategies involve spraying impacted waterways and the plunging-jet method is critical to see whether these strategies have unintended consequences for human exposure to HAB toxins. A significant complication encountered was the process of creating spray with heterogeneous lake water samples where algae would aggregate and created mats that could either float on the surface or sink to the bottom of the tank. While both tanks faced unforeseen complications, it is hopeful that they can provide future projects with a more realistic technique to investigate surfactant aerosolization in a laboratory setting. With HAB events increasing in frequency, it is important to be able to create realistic conditions in a laboratory setting to fully investigate the dynamic system of toxin aerosolization.
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