Bioaccessibility of Toxic Elements In Dusts from Dry Saline Lakes In the Mojave Desert (USA)

Adverse health effects from exposure to ambient particulate matter have been typically studied in urban or occupational settings examining anthropogenic input such as combustion by-products. Fewer studies have examined health issues related to particulate matter contributions from rural, non-agricultural sources. Surface sediment on some dry lake beds may contribute significant amounts of mineral dusts to the atmospheric load. For example, Owens (dry) Lake (southern California) has been a major source of PM10 (particulate matter less than 10 micrometers) dust in the United States. Dusts from dry and drying saline lakes may contain high concentrations of metals, such as arsenic, with known human health toxicity. Physiologically based extraction tests (PBETs) are inexpensive in vitro tests designed to estimate the bioaccessibility of metals in soils, dusts and other environmental materials by measuring the chemical reactivity of the materials in simulated body fluids (SBFs).

Bioaccessibility is defined as the fraction of a potential toxicant that becomes soluble in the simulated gastric, intestinal, lung or lysosomal fluids, and is an indication of the amounts of a toxicant that may be available for absorption through dust ingestion or inhalation. PBETs were conducted on artificially generated dust samples from Franklin Lake and Mesquite Lake playas in the Mojave Desert. To provide more information on bioaccessibility, speciation of arsenic and chromium was evaluated using high performance liquid chromatography (HPLC) separation with ICP-MS detection.