Geochemical Characterization of Sediments that are a Source of Wind-Borne Dust from the Nellis Dune Recreation Area, Clark County, Nevada

Haggard, Sarah M.; Baron, Dirk; and Horton, Robert A.
[email protected]

Nellis Dunes Recreational Area is located approximately 6 km northeast of Las Vegas, Nevada and has been used for off-road vehicular recreation for over 40 years. The study area is approximately 37 km² and is managed by the Bureau of Land Management. Extensive studies have been performed on the sediments to determine potential health risks related to the current land use. One of the potential health risks identified in previous studies is high levels of arsenic. According to Soukup et al (2012) values were found as high as 312 µg g^-1 of total arsenic and up to 14.7 µg g^-1 of soluble arsenic. For the purposes of this project, sediment samples were taken from surface units containing the highest arsenic levels from the Nellis Dune Recreation Area and were studied with scanning electron microscopy (SEM) using energy-dispersive and wavelength-dispersive spectrometers (EDS and WDS). Measurable concentrations of arsenic were detected in iron-oxyhydroxide grain coatings. Due to the thin grain coatings and the electron-beam spot size, silicates were also analyzed with the grain coatings which likely caused lower arsenic levels to be detected. This study will contribute to further research and be useful for development of a management plan for the Nellis Dunes Recreational Area.

AAPG Search and Discovery Article #90162©2013 Pacific Section AAPG, SPE and SEPM Joint Technical Conference, Monterey, California, April 19-25, 2013