[CPEO-MEF] Perchlorate Uses and Environmental Occurrence

[Lenny Siegel <lsiegel@cpeo.org>]

Submitted by Laura Olah <info@cswab.org>

Perchlorate Uses and Environmental Occurrence

Perchlorate is an environmental contaminant that seldom occurs naturally 
except in evaporite deposits in extremely arid regions (Orris et al. 
2003). Recent analyses of Chile saltpeter (sodium nitrate) by USEPA and 
the Department of Energy have found concentrations of approximately 1 g 
ClO4 –/kg NaNO3 Urbansky and Schock 1999). Chile saltpeter is used as a 
fertilizer, particularly favored by tobacco farmers, resulting in 
accumulation of perchlorate in tobacco products (Ellington et al. 2001). 
Commercial quantities of sodium perchlorate are usually prepared by 
electrolysis of aqueous solutions of sodium chloride, in which the 
chloride ion is successively oxidized through hypochlorite (ClO–), 
chlorite (ClO2–), chlorate (ClO3 –), and finally to perchlorate (ClO4–).

Large commercial quantities of ammonium perchlorate are used in 1.3-inch 
diameter solid rocket motors and to a limited extent in pyrotechnic and 
explosive compositions. Potassium perchlorate is used extensively in 
pyrotechnic compositions and in black-powder-substitute gun propellants. 
It is used in some spotting charges that enable range control personnel 
to assess the accuracy of inert (nonexplosive) rounds. Perchlorate salts 
are also used in nuclear reactors, electronic tubes, as additives in 
lubricating oils, in tanning and finishing of leather, as mordents for 
dyed fabrics, in electroplating and electropolishing, aluminum refining, 
rubber manufacture, and in the production of paints and enamels.

Commercial production of chlorate used for herbicides and bleaching 
agents is by the incomplete electrolysis of sodium chloride. Analysis of 
laboratory-grade chlorate found nearly % levels of perchlorate (Burns et 
al. 1989). It is reasonable to assume that industrial-grade chlorate may 
contain several % of perchlorate as a result of slight variations in 
process conditions.

In years past, railroads used sodium chlorate as an ingredient in 
herbicides to suppress the growth of foliage along rail corridors. Where 
rainfall is low or intermittent, soils around railbeds may still be 
contaminated with perchlorate. Another uninvestigated source of 
perchlorate contamination around railways is from spillage of chlorate 
salts used for bleaching at paper mills.

SOURCE:  Field Screening Method for Perchlorate in Water and Soil 
(ERDC/CRREL TR-04-8).  This report was published by the U.S. Army Corps 
of Engineers.  A reliable and inexpensive colorimetric method for 
perchlorate in water and soil extracts has been developed and tested 
with surface water, well water, bioreactor effluent, and soil extracts. 
The detection limit for water is 1 ug/L and 0.3 ug/g for spiked soils. 
Results from nearly 100 well water and bioreactor samples show excellent 
agreement with EPA Method 314 over the range of 1-225 ug/L (slope = 
1.11, R2 = 0.913). Some false positives were encountered in some wells. 
A cleanup method was developed that can eliminate false positives due to 
humic substances (April 2004, 26 pages).  View or download at 
http://www.crrel.usace.army.mil/techpub/CRREL_Reports/reports/TR04-8.pdf

--

Laura Olah, Executive Director
Citizens for Safe Water Around Badger
E12629 Weigands Bay S
Merrimac, WI 53561
phone: (608)643-3124
fax: (608)643-0005
email: info@cswab.org
website: www.cswab.org



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