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Article
Application of field portable-XRF to the analysis of desert varnish samples in areas impacted by coal-fired power plants
Environmental Chemistry
  • Piotr Nowinski, Clark Counry Department of Air Quality
  • Vernon F. Hodge, University of Nevada, Las Vegas
  • Shawn Gerstenberger, University of Nevada, Las Vegas
Document Type
Article
Publication Date
7-30-2012
Abstract
Desert varnish samples were collected near two coal-fired power plants to determine if the varnish contained a record of recent air pollution. Samples were collected: (1) in the fallout patterns of the shuttered Mohave Power Plant (MPP), located in Laughlin, NV; and (2) near the operating Reid-Gardner Power Plant (RGPP), just east of Las Vegas, NV. Small pieces of varnished rocks were analysed by field portable X-ray fluorescence spectroscopy (FPXRF). Results were obtained for 15 elements: Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Zr, Mo, Hg and Pb. The FPXRF data indicate that the elements commonly found in fly ash from coal-fired power plants (e.g. Cr, Zn, As and Pb) had significantly higher concentrations in the rock coatings in relation to the unvarnished substrate rock. For one of the power plants, where tracer plume studies had been carried out, the highest concentrations in the desert varnish coincided with the peak tracer concentration locations. Thus, these elements in desert varnish hold promise for identifying those geographical regions affected by nearby power plants. However, additional samples are required to demonstrate unequivocally that the power plants are indeed the sources of these elements. Overall, it is apparent that desert varnish can be utilised as a passive environmental monitor to investigate recent air pollution (past 20–30 years) and that FPXRF can be used as a surveying tool to obtain multi-element data from a large number of samples.
Keywords
  • Air – Pollution,
  • Coal-fired power plants,
  • Desert varnish,
  • Environmental monitoring,
  • Nevada – Clark County,
  • Pollution sources,
  • Rocks – Surfaces,
  • Trace metals,
  • X-ray spectroscopy,
  • XRF
Language
English
Permissions
Use Find in Your Library, contact the author, or interlibrary loan to garner a copy of the item. Publisher policy does not allow archiving the final published version. If a post-print (author's peer-reviewed manuscript) is allowed and available, or publisher policy changes, the item will be deposited.
Identifier
DOI: http://dx.doi.org/10.1071/EN11139
Publisher Citation
Piotr Nowinski, Vernon F. Hodge, Shawn Gerstenberger , Environ. Chem. 2012, 9, 379.
Citation Information
Piotr Nowinski, Vernon F. Hodge and Shawn Gerstenberger. "Application of field portable-XRF to the analysis of desert varnish samples in areas impacted by coal-fired power plants" Environmental Chemistry Vol. 9 Iss. 4 (2012) p. 379 - 388
Available at: http://works.bepress.com/shawn_gerstenberger/7/