AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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Formation of Metal-Ligand Complexes in Atmospheric Aerosol and Their Effects on ROS Production in a Surrogate Lung Fluid
CHIARA GIORIO, Sara D'Aronco, Alessandro Negro, Valerio Di Marco, Andrea Tapparo, Università degli Studi di Padova, Italy
Abstract Number: 246 Working Group: Health-Related Aerosols
Abstract Aqueous phase processing of aerosol can lead to substantial modifications of aerosol chemical and physical properties. A process potentially very important in this context is the formation of metal-organic ligand complexes in atmospheric aqueous phases, like fog/cloud droplets and deliquescent aerosol. Such process can increase the solubility of metals, therefore their bioavailability, and affect their capability to generate reactive oxygen species (ROS). We investigated the formation of metal-organic ligand complexes, especially those involving small dicarboxylic acids, in urban aerosol collected at an urban background site in the city centre of Padua (Italy), in the Po Valley. We assessed the effects of metal-ligand complexes formation on the solubility and solubilisation kinetic of metals from the particles to aqueous solutions simulating fog/cloud water and a model pulmonary fluid. Preliminary results show that iron, copper and manganese are present in the aerosol in a complexed form, mainly with oxalate, malonate and succinate. Iron was the metal whose solubility was the most influenced by the presence of organic ligands. Solubilisation kinetics of many metals depended on the form in which they are present in the aerosol and they were influenced by the environmental conditions during the campaign. Changes in particle toxicity due to the formation of metal-ligand complexes was investigated in a model pulmonary fluid specifically developed to simulate the metal-ligand equilibria that might be established in a real pulmonary fluid. The ability of particles to generate ROS was tested based on the oxidation kinetic of glutathione and ascorbic acid to assess whether the formation of metal-ligand complexes increase or decrease particle toxicity.