DIRT ON THE STREETS: ENVIRONMENTAL AND HEALTH IMPACTS OF URBAN ROAD DUST IN LITTLE ROCK, ARKANSAS

Air and dust pollution are two very significant environmental issues within urban areas, with road dust being a source and route for water contamination, human exposure, and contact with other living organisms and ecosystems. The focus of this investigation is on the implications of road dust on the water quality, people, and organisms/ecosystems around Little Rock, Arkansas. The Little Rock Metropolitan area is made up of many different neighborhoods nestled around anthropogenic activities like transportation, mining, farming, and manufacturing, as well the Arkansas River and Fourche Creek Watershed, which are both important ecological and commercial resources in the area. These activities in combination with vehicle traffic can result in a significant accumulation of contaminated dust and particulate matter along roadways; and rain events and wind can remobilize and resuspend road dust into the water and air. Samples of road dust were collected using a handheld vacuum from six locations around the Little Rock Metro area during the Spring and Summer 2021. The locations were selected to represent the end members near mining, farming, manufacturing, and vehicle traffic. In order to determine the potential impact of road dust on local air and water quality, the samples were sieved and grain size fractions were measured. The smallest particles (>63ⲙm) were used in leaching experiments in deionized water to simulate a rain event with a 1:20 solid to liquid ratio at room temperature for 24 hours. A simulated lung fluid, AFL (artificial lysosomal fluid), was used to simulate what might take place inside the upper parts of the lungs after inhaling road dust particles (<10 ⲙm) at a 1:20 solid to liquid ratio for 24 hours at 37℃. Dust particles of ingestible size were used in leaching experiments in simulated gastric fluid at a 1:100 solid to liquid ratio for one hour at 37℃. The leachates from the experiments were then filtered and analyzed by ICPMS for trace elements and ion chromatography for cations and anions. Several of the sampling sites had elevated concentrations of cations and metals relative to background sediment within the watershed.. This research will help shed light on urban pollution and contamination and potential impacts on those who live in and near urban environments.