C. Lehr J. Matschullat B.J. Merkel D. Kirk Nordstrom Mark W. Sandstrom B. Planer-Friedrich 2006 <div id="abstracts" class="Abstracts"><div id="aep-abstract-id13" class="abstract author" lang="en"><div id="aep-abstract-sec-id14"><p>Geothermal features in the Yellowstone National Park contain up to several milligram per liter of aqueous arsenic. Part of this arsenic is volatilized and released into the atmosphere. Total volatile arsenic concentrations of 0.5–200&nbsp;mg/m³<span>&nbsp;</span>at the surface of the hot springs were found to exceed the previously assumed nanogram per cubic meter range of background concentrations by orders of magnitude. Speciation of the volatile arsenic was performed using solid-phase micro-extraction fibers with analysis by GC–MS. The arsenic species most frequently identified in the samples is (CH₃)₂AsCl, followed by (CH₃)₃As, (CH₃)₂AsSCH₃, and CH₃AsCl₂<span>&nbsp;</span>in decreasing order of frequency. This report contains the first documented occurrence of chloro- and thioarsines in a natural environment. Toxicity, mobility, and degradation products are unknown.</p></div></div></div> application/pdf 10.1016/j.gca.2006.02.019 en Elsevier Speciation of volatile arsenic at geothermal features in Yellowstone National Park article