Title

Application of field portable-XRF to the analysis of desert varnish samples in areas impacted by coal-fired power plants

Document Type

Article

Publication Date

7-30-2012

Publication Title

Environmental Chemistry

Volume

9

Issue

4

First page number:

379

Last page number:

388

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

Disciplines

Environmental Indicators and Impact Assessment | Environmental Monitoring | Environmental Sciences | Geochemistry | Geomorphology | Oil, Gas, and Energy

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.

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