Accumulation of salt-rich dust from Owens Lake playa in nearby alluvial soils

Over the last 100 years, Owens Lake playa in eastern California has been one of the largest point sources of PM-10 dust in the United States. Here we evaluate the spatial impact of the salt-rich playa dust on the alluvial piedmont soils of Owens Valley with the expectation that those nearest the playa will have the highest concentrations of playa-derived salts. We sampled soils of similar age on alluvial fans derived from Sierra Nevada granites along the valley axis to determine soluble salt and specific ion concentrations. Salt concentrations are indeed highest in those soils most proximate to the playa, with higher levels of sodium and elevated pH. However, one site directly north of the playa has significantly higher salt concentrations as measured by electrical conductivity (EC) compared to all other soils sampled, an average pH of about 10 and a sodium adsorption ratio (SAR) greater than 15, suggesting a strong impact of local dust as a result of local topography and wind patterns. Although EC, pH, and SAR of other sampled soils fall into normal ranges for sandy granitic soils in a semi-arid climate, the soils closer to the playa show greater salt and sodium impact than those further away. The strong local impact of playa salts and the patterns of salt contribution away from the playa suggest a spatial effect of dust on the alluvial soils that will grow both in intensity of impact and in distance from the playa if dust fluxes remain at recent levels.

► We evaluate the impact of salt-rich dust from Owens Lake playa on surrounding soils.
► We measure soluble salt and specific ion concentrations in similar soils along valley.
► Salt concentrations, Na and pH are highest in soils most proximate to the playa.
► One site just north of the playa has significantly higher salt concentrations and pH.
► Results suggest a strong impact of dust modulated by topography and wind patterns.