T358 Urban Geochemistry (Posters)

Wednesday, 30 October 2013
9:00 AM - 6:30 PM
Hall D

A PRELIMINARY SPATIAL EVALUATION OF LEAD CONCENTRATION BY ROAD DUST PARTICLE FRACTION AND THE PUBLIC HEALTH IMPLICATIONS IN NPU-V, ATLANTA, GEORGIA

Paper number: T358-7
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM

Authors

Abstract

Road dust is a well-established reservoir for lead (Pb) in urban environments, attributable to historic use of leaded gasoline and lead-based paint, as well as industrial activity. The purpose of this study is to determine the spatial distribution of Pb by size fraction in road dust collected in Neighborhood Planning Unit-V (NPU-V), a low income neighborhood south of downtown Atlanta, GA, using microanalytical, geochemical and statistical methods. In doing so, we hope to better understand how Pb in road dust interacts with the built environment to contribute to childhood lead exposure and the negative health outcomes that result. Road dust samples were taken from 40 sites across the southern half of NPU-V using filtered vacuum collection. At each site, dust was sieved through the vacuum into four size fractions—2.2-34μm, 35-99μm, 100-249μm, and 250-999μm. Pb content within each size fraction was determined for all 40 sites using energy-dispersive X-ray fluorescence (XRF). Lead was detected at levels ranging from not detected to 884 mg/kg. Median lead concentrations were 16 mg/kg, 23.5 mg/kg, 53.3 mg/kg, and 47.8 mg/kg for the 2.2-34μm, 35-99μm, 100-249μm, and 250-999μm size fractions, respectively.

The Pb concentrations were plotted geographically using ArcGIS 10.1. Resultant maps showed higher Pb concentrations in a central area composed of primarily residential roads; however, a correlation coefficient revealed no significance in the relationship between road type and Pb concentration. Geospatial analysis also indicated elevated Pb concentrations proximal to an expressway (I-75/85) and a railroad (CSX) for each size fraction, as well as highly variable concentrations along arterial roads. This variability in arterial road dust Pb concentration may have been indicative that the road dust was out of equilibrium, given the heavy rainfall that occurred in NPU-V two days prior to collection; future road dust collection at proximal or identical points could further address this question.

The findings in this preliminary evaluation give us insight into the impact of the built environment and historic land use practices on contemporary health outcomes, as well as provide quantitative geochemical data to further characterize environmental hazards in both urban environments and NPU-V, specifically.