Aerosolized Algal Toxins in South Florida, Health Impacts, and Exposure Mitigation Strategies

CASSANDRA GASTON, Kimberly Popendorf, Haley Royer, Raymond Leibensperger III, Michael Sheridan, Jiaming Hu, Kaycie Lanpher, Daniela Maizel, Grace Zhai, Helena Solo-Gabriele, Larry Brand, Alberto Caban-Martinez, University of Miami

     Abstract Number: 128
     Working Group: Aerosol Sources and Constituents of Emerging Importance and Their Impacts across Spatial Scales

Abstract
Harmful algal blooms of cyanobacteria (e.g., CyanoHABs) can produce toxins, including microcystins (MCs), that can be aerosolized from contaminated lakes, rivers, canals, and other waterways. Inhalation of aerosolized MCs are thought to be a more potent form of exposure than dermal contact or ingestion, yet little is known about the aerosolization potential and health impacts of inhaled MCs and other CyanoHAB toxins. We measured MCs in both waterways and air in regions of South Florida impacted by HABs and found concentrations of MC in water in excess of drinking water guidelines as well as detectable MC in aerosols. To probe the health impacts of our findings, we bubbled contaminated lake and canal water samples and the generated aerosols were used to expose fruitflies, Drosophilia megalomaster—a model organism with a short enough lifespan to probe both acute and chronic health impacts. Juvenile fruitflies exposed to aerosolized Cyano-HAB toxins had shorter lifespans, altered motor capabilities, and deteriorated synaptic function compared to our control groups. Finally, we investigated mitigation strategies to reduce the inhalation of Cyano-HAB toxins both indoors and outdoors using face masks and air conditioner (AC) filters. Particle transmission efficiencies and toxin filtration efficiencies were measured and for the AC filters were found to scale with the manufacturer-provided filter performance ratings. Up to 80% of small, microcystin-containing aerosols were transmitted through AC filters with low filter performance ratings. Hydrophobic congeners of MC including MC-LF and MC-LW were enriched in aerosols compared to water, with MC-LR being the most abundant form, which has implications for the toxicity of aerosols generated from HAB-contaminated waters. Given that HABs are predicted to increase worldwide, knowledge of the health impacts associated with the inhalation of aerosolized HAB toxins are needed in addition to effective mitigation strategies to prevent airborne exposure.