Arsenic concentrations in dust emissions from wind erosion and off-road vehicles in the Nellis Dunes Recreational Area, Nevada, USA

Field and laboratory experiments were performed in the Nellis Dunes Recreational Area near Las Vegas, NV, USA to evaluate arsenic concentrations associated with dust emissions from wind erosion and off-road vehicles. Soil samples were collected from 17 types of desert surfaces and five unpaved parking lot locations for analyses. The surface units are based on surficial characteristics that affect dust emissions. Arsenic concentrations were also measured in dust emitted from each surface unit using a Portable In Situ Wind Erosion Laboratory (PI-SWERL). Emissions were measured from ORV trails and undisturbed terrain. Concentrations of As in the soil and parking lot samples ranged from 3.49 to 83.02 μg g−1 and from 16.13 to 312 μg g−1 in the PI-SWERL samples. The lower concentrations in the soil samples are expected because of the larger particle sizes (<2 mm) as compared to the PI-SWERL samples (<10 and 10–60 μm). Soluble As in the PI-SWERL samples was as high as 14.7 μg g−1. In the Nellis Dunes area the emission rates for As for wind-induced emissions (wind erosion) are highest for the surfaces with significant amounts of sand. Surfaces rich in silt and clay, on the other hand, produce nearly no arsenic during wind erosion but can emit substantial arsenic concentrations when driven on by off-road vehicles. The elevated arsenic emissions from the Nellis Dunes area are of great concern because the site is located in the immediate vicinity of the city of Las Vegas, and utilized by over 300,000 visitors annually.