GSA Connects 2021 in Portland, Oregon

Paper No. 84-8
Presentation Time: 9:00 AM-1:00 PM


GOKEY, Kailee1, GILLIS, Morgan1, KREKELER, Mark2, RENKES, Natalie G.3 and BROWN, Ken4, (1)Department of Geology and Environmental Earth Science, Miami University, 250 S. Patterson Avenue, Oxford, OH 45056, (2)Department of Geology and Environmental Earth Science, Miami University - Hamilton, Hamilton, OH 45011, (3)Department of Geoscience, University of Nevada Las Vegas, 4505 S Maryland Parkway, Las Vegas, NV 89154, (4)Department of Geosciences, DePauw University, 2 E. Hanna Street, Greencastle, IN 46135

Street sediments provide an easily accessible medium for textural and geochemical characterization of contaminant and natural material from a given area. They have several regional inputs, including anthropogenic, geogenic, and biogenic materials, which contribute to their complex nature. Due to the complexity of street sediments, they are a source and sink for contaminants.

Previously, some studies have analyzed urban street sediments and their characteristics in eastern and midwestern US cities; however, there have been no detailed studies regarding street sediments in arid urban environments in the US. Arid street sediments may be fundamentally different from those observed in previous studies, and this study aims to characterize street sediment materials and potential contaminants. Detailed analysis of urban street sediments from Las Vegas would allow for geochemical and textural characterization of the sediments and any potential contaminants within. This would further enable study of any potential negative human health implications that these contaminants may pose.

Forty-six street sediment samples have been collected from different locations in the Las Vegas Valley. Thus far, several samples have been chemically and texturally analyzed via a Scanning Electron Microscope (SEM), and Transmission Electron Microscope (TEM). Preliminary SEM data shows fibrous minerals rich in elements such as Ca, Mg, Fe, and Al, as according to energy dispersive spectrometry (EDS), which indicates the presence of potential asbestiform materials. There is also evidence of anthropogenic spherules, iron oxides, and rare earth elements (REE’s). Preliminary TEM data shows geogenic components to be palygorskite, calcite, and amorphous iron oxides. TEM indicates potential contaminant materials such as Zn, Pb, V, and Cr are also present.

Initial observations of Las Vegas street sediments merits additional analysis to better define textural and chemical characteristics. Further investigations will provide context into the potential human health hazards of these pollutant materials.