TEXTURAL AND GEOCHEMICAL ANALYSIS OF HEAVY METAL CONTAMINANTS PRESENT WITHIN LAS VEGAS, NEVADA ROAD SEDIMENTS

Road sediments are an easily accessible medium that provide insight into the environmental background of a given area. They contain a wide variety of geologically and anthropogenically derived materials, which contributes to their complex nature. Due to the complexity of road sediment contents, they are both a source and sink for contaminants that may be harmful to human health.

Previous street sediment studies have focused primarily on heavy metal contamination in eastern and mid-western US cities (i.e. Gary, IN, Philadelphia, PA, Hamilton, OH). Relatively few studies, however, have examined heavy metal concentrations in street sediments within arid environments in the U.S., where windborne sediment transport likely plays a significant role in the redistribution of these harmful metals. This research aims to provide a detailed analysis of heavy metal content of road sediments from the Las Vegas Valley, Nevada. A detailed analysis of urban road sediments from throughout the Las Vegas Valley allows for geochemical and textural characterization of any heavy metal contaminants found within. Characterization of these potential contaminants would assist in identifying potential environmental concerns that may pose a negative impact to human health.

Forty-six street sediment samples have been collected from various locations throughout the urbanized Las Vegas Valley. Thus far, several samples have been chemically and texturally analyzed via a scanning electron microscope (SEM), transmission electron microscope (TEM), and all samples have been chemically analyzed via a handheld X-ray fluorescence (XRF) spectrometer. Preliminary SEM and TEM data shows geogenic components to be palygorskite, calcite, and amorphous iron oxides present in most samples analyzed, as well as heavy metal contaminants such as Zn, Pb, Cr, and V according to energy dispersive spectrometry (EDS). XRF analyses indicate that there may be some correlation between heavy metals such as Cu and Zn, Fe and As, and Mn and As.

Initial observations of Las Vegas Valley road sediments merit additional analysis of urban road sediments in arid environments to provide context into any potential human health hazards of heavy metals or other contaminants found