Atmospheric Process and Enrichment of Microcystin-LR in Lake Spray Aerosol during Harmful Algae Blooms

BAHARAN EMAM, Myoseon Jang, University of Florida

     Abstract Number: 253
     Working Group: Aerosol-Ecosystem Interactions

Abstract
During freshwater harmful algae blooms (HAB), the potential for exposure to aerosolized cyanobacterial algal toxins is not well studied. These toxins represent a range of threats to ecosystem, animal survival, and human health. Over 250 different microcystins have been discovered, of which microcystin-LR(MC-LR) is the most common. Waterborne MC-LR has been widely studied due to its severe hepatotoxicity but the adversity of airborne MC-LR in algal aerosol is poorly investigated. A fundamental question remains over the enrichment of MC-LR in freshwater algal aerosol and its longevity in aerosol. Airborne MC-LR can be enriched in algal aerosol, which is created from the bursting of bubbles at the lake and estuaries’ surface. In this study, water and lake-spray aerosol (LSA) are collected in HAB sites in Florida. LSA is collected by using the Particle-Into-Liquid-Sampler (PILS) with the modified method with a minimal use of water. MC-LR in both water and LSA samples is analyzed with the Enzyme-Linked ImmunoSorbent Assay (ELISA). The characterization of water and LSA is performed to identify the quantity of organic matter (OM) and inorganic compositions (sulfate, nitrate, ammonium, sodium, and potassium). ELISA or OM data were normalized with ionic constituents to examine enrichment of MC-LR and OM. The recent chamber study finds the rapid degradation of MC-LR in cyanobacterial aerosol. The simulated MC-LR decay by the kinetic model (i.e., Harmful Algal Aerosol Reaction (HAAR) model) based on chamber study suggests that the lifetime of MC-LR is in the scale of several minutes. The longevity of MC-LR in LSA during HAB is examined by measuring MC-LR as a function of distance from the source and compared with chamber observation. Additionally, the light absorbance of cyanobacterial aerosol is measured in situ with a reflectance micro-UV spectrometer. The change of functional groups in LSA is also analyzed with FTIR data.