Paper No. 2
Presentation Time: 9:00 AM-6:00 PM




Urban road dust and soils in areas linked to historical use of leaded paints and gasoline have been previously identified as important human exposure pathways to lead (Pb). This study examines whether the spatial distribution, chemical composition, and relative concentrations of Pb in soils and dust can be implicated in negative health outcomes in Neighborhood Planning Unit V (NPU-V), Atlanta. Soil and road dust samples at 150 sites across NPU-V were analyzed using statistical, microanalytical, and geochemical methods. Pb was detected at levels ranging from below background (10.67 mg/kg) to toxic levels (968.33 mg/kg) based on X-ray fluorescence (XRF), with median levels falling above background for each sample type. Each dust sample was sieved and < 250 µm particles were tested again. Smaller particles had significantly higher levels than bulk samples. Pb was not detected with scanning electron microscopy (SEM). Multivariate regression showed that samples with the highest Pb concentrations were analyzed using X-ray diffraction (XRD). Soil Pb distributions were inversely correlated to land use type and distance from arterial roadways. Dust was directly correlated to distance from expressways and inversely correlated to distance from major roads. These results can be implicated in potential negative health outcomes. The methods employed also provide insight for future studies of urban Pb deposition and potential effects on human health. Higher Pb in fine dust particles is concerning as smaller particles are more readily airborne and inhaled. Soil Pb was higher near arterial roadways and in non-industrial areas, which are both linked to spaces where people spend a lot of time. Dust levels were higher near arterial roadways, but the positive correlation with highways may reflect dust’s ability to be transported further. Geospatial analysis shows that Pb concentrations in NPU-V are strongly tied to the built environment and can be attributed to urban planning decisions. SEM and XRD results indicate a need to improve the methodology in order to effectively identify the chemical state of Pb and potential interactions with human physiology. This study demonstrates how past societal practices can have profound affects on the health outcomes of contemporary populations.