44 Environmental Geoscience (Posters)

Wednesday, 11 March 2026
9:00 AM - 12:00 PM
RCC, Lower Level Hall

Transmission electron microscopy investigation of road sediment near Harry Reid International Airport, Las Vegas, Nevada.

Paper number: 44-4
Program: Technical Sessions
Time: 9:00 AM – 9:00 AM

Authors

Abstract

Previous high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) investigations showed moderate pollution levels in road sediment samples taken adjacent to the Harry Reid International Airport in Las Vegas, Nevada. This sampling location was picked due to its high volumes of air traffic, arid climate and an existing road sediment data set of the Las Vegas area for comparison. HR-ICP-MS revealed that no specific metal pollutant seems unique to the airport setting in road sediment, but pollutants were present. The metals, Pb, Zn, Cu, and Hg were identified in quantities above normalized upper continental crust (UCC) values. Pb was found in the quantity (10.84 to 68.24 ppm), Zn (73.19 to 214.72 ppm), Cu (23.20 to 444.45 ppm) and Hg (BDL to 0.95 ppm). Hg samples found above detection limit were all concentrated in one traffic intersection immediately adjacent to the airport, samples away from it were below detection limit. Scanning transmission electron microscopy - energy dispersive spectroscopy (STEM-EDS) mapping of sediment aggregates on the scale of 1 micrometer indicates a high degree of chemical complexity. Aggregates are mixtures of oxides, silicates, and clay minerals with variable distributions of elements of environmental concern. Pb and As are largely localized into nanometer scale phases and have some diffuse distributions. Cu, Zn, Cr, and Co when observed, tend to have more diffuse distributions and suggest these metals are adsorbed to aggregates. No discrete Hg phases were observed. These results provide constraints on the particle size and chemical composition of some elements of environmental concern and help support observed correlations of concentrations of Pb and Zn and the general lack of correlations in concentrations of many other elements of environmental concern. A possible reason for the lack of both spatial and bulk concentration correlations in Las Vegas sediment data is a combination of the diverse mineral substrates observed, combined with the overall arid climate making dissolution-reprecipitation-adsorption processes less pronounced compared to other settings. This work highlights that there are metals of concern in the micrometer to nanoparticle size fraction of road sediment material and thus provide some general constraints on exposure concerns.

Geological Society of America Abstracts with Programs. Vol. 58, No. 1

doi: 10.1130/abs/2026SE-411618

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