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Paper No. 196-7
Presentation Time: 2:00 PM-6:00 PM
MICROPLASTICS IN LARGE HAILSTONES FROM TWO CENTRAL TEXAS SUPERCELL THUNDERSTORMS
Microplastics (MPs) have been reported in ecosystems across the globe to which atmospheric transport has been considered differentially contributary depending on air cell moisture. Hailstones are formed in the updraft regions of supercell or multicell storms and grow as supercooled droplets collect and freeze on the surface as the hailstone rises or falls. Hailstone residence time is critical to hailstone growth and allows for the deposition or accretion of anthropogenic matter suspended in the atmosphere to accrete. There is a lack of data in identifying whether atmospheric MPs are collected as precipitation falls or if they behave like other particulate matter that influence the formation and dynamics of precipitation events. We hypothesize that hailstones record signatures of atmospheric conditions at time of formation and growth in the form of microplastic constituents. We hypothesize that hailstones may record signatures of atmospheric conditions at time of formation and growth in the form of microplastic constituents. In this study, we provide microplastics characterization of 65 hailstones collected from 2 different storms in 2020 and 2021, from Del Rio, and Uvalde Texas, respectively. This study used large hailstones ranging from 47 to 86 mm in diameter with mass ranging from 58 to 199 gr. Hailstones were allowed to melt at room temperature in glass containers and MPs were extracted using vacuum filtration with 20µm glass filter membranes followed by visual microscopy. MP fibers were the predominant morphotype found among all hailstones. Polyester, cellulose acetate, polyester/cellulose blends characterize majority of the fibers. Potential MPs were marked for further analysis using Fourier Transform Infrared Spectroscopy (FTIR) or Raman Spectroscopy for confirmation and polymer identification. This study is the first to validate MPs in hailstones and provides evidence that MP fibers circulate in the upper troposphere and lower stratosphere.