Speciation of iodine in the salt-impacted Black Butte soil series along the Virgin River, NV

ENVR 136

Spencer M. Steinberg, spencer.steinberg@unlv.edu1, Brenda Buck2, Janet Morton2, and James Dorman1. (1) Department of Chemistry, University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154, (2) Department of Geoscience, University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154
Salt-impacted soils occur in floodplains, wetlands and backswamps in arid climates and may be a consequence of irrigation and seasonal precipitation. Salt-impacted soils become sinks or temporary storage sites for soluble salts and anthropogenic contaminants including agricultural chemicals, industrial pollutants and radionuclides such as 127I. The objective of this project was to assess the vertical distribution of iodine in the Black Butte soil series along the Virgin River and to determine distribution of iodine between iodide, iodate and organically bound iodine. The speciation of iodine was compared to the organic carbon content, specific components of the organic carbon and clay content. Total organic carbon was quantified by an automated combustion method. In addition, the molecular character of organic matter was semi-quantitatively characterized by pyrolysis and TMAH-promoted chemolysis. Soluble iodine and iodate were measured after water extraction while organic iodine content was estimated by pyrolysis which releases organic iodine as methyl iodide. This study indicates that organic iodine was the most abundant form of iodine in the soil samples and that the content of organic iodine was correlated to total organic matter and to the lignin content (as measured by chemolysis) of the samples.
 

General Papers
6:00 PM-8:00 PM, Wednesday, August 22, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Environmental Chemistry

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007