&EPA
United States
Environmental Protection
Agency
Technical Fact Sheet-
Perch lorate
May 2012
TECHNICAL FACT SHEET - PERCHLORATE
Introduction
At a Glance
* White crystalline solid or colorless
liquid.
* Both naturally occurring and man-
made.
* Sampling at current federal sites as
well as Formerly Used Defense
Sites detected perchlorate primarily
in association with sites historically
involved in the manufacture,
maintenance, use, and disposal of
ammunition and rocket fuel.
* Highly soluble in water; migrates
quickly from soil to ground water.
* Primary pathways for human
exposure include ingestion of food
and contaminated drinking water.
* Short-term exposure to high doses
may cause eye and skin irritation,
coughing, nausea, vomiting, and
diarrhea.
* Health-based goals or drinking
water standards developed by
various states.
* Various detection methods
available include ion
chromatography, liquid
chromatography, mass
spectroscopy, and electrospray
ionization.
* Common treatment technologies
include ion exchange, bioreactors,
and in situ bioremediation.
This fact sheet, developed by the U.S. Environmental Protection Agency
(EPA) Federal Facilities Restoration and Reuse Office (FFRRO),
provides a brief summary of the contaminant perchlorate, including
physical and chemical properties; environmental and health impacts;
existing federal and state guidelines; detection and treatment methods;
and additional sources of information.
Perchlorate is a persistent contaminant of concern that has presented a
number of issues to the government, the private sector, and other
organizations and interested parties. These issues include health effects
and risk, regulatory standards and cleanup levels, degradation
processes, and treatment technologies (EPA FFRRO 2005). This fact
sheet provides basic information on perchlorate to site managers and
other field personnel who are addressing perchlorate contamination at
cleanup sites or in drinking water supplies.
What is perchlorate?
»> Perchlorate is a naturally occurring and man-made anion (CIO4~) that
consists of one chlorine atom bonded to four oxygen atoms (EPA
FFRRO 2005; ITRC 2005).
»> Perchlorate may occur naturally, particularly in arid regions such as
the southwestern United States (Rao 2007).
»> Manufactured forms of perchlorate include perchloric acid and salts
such as ammonium perchlorate, sodium perchlorate, and potassium
perchlorate (EPA FFRRO 2005; ITRC 2005).
»> Perchlorate is found as a natural impurity in nitrate salts from Chile,
which are imported and used to produce nitrate fertilizers and other
products (EPA FFRRO 2005; ITRC 2005).
»> Perchlorate is commonly used as an oxidizer in solid propellants,
munitions, fireworks, airbag initiators for vehicles, matches, and
signal flares (EPA FFRRO 2005; ITRC 2005). It is also found in
some disinfectants and some herbicides (ITRC 2005).
»> Of the domestically produced (high grade) perchlorate, 90 percent is
estimated to be used in the defense and aerospace industries in the
form of ammonium perchlorate (GAO 2005; ITRC 2005).
»> Perchlorate has been used by the U.S. Department of Defense
(DoD) as an oxidizer in munitions and missiles since the 1940s
(Mendiratta et al. 1996).
United States
Environmental Protection Agency
Office of Solid Waste and
Emergency Response (5106P)
1
EPA 505-F-11-003
May 2012
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Technical Fact Sheet - Perchlorate
Exhibit 1: Physical and Chemical Properties of Perchlorate Compounds
(EPA FFRRO 2005; ITRC 2005; NIOSH 2007)
Property
CAS Numbers
Physical Description
(physical state at room
temperature)
Molecular weight
(g/mol)
Water solubility (g/L at
25°C)
Melting / Boiling point
(°C)
Vapor pressure at 25°C
(mm Hg)
Specific gravity
Octanol-water partition
coefficient (log Kow)
1 Ammonium Sodium
Perchlorate Perchlorate
7790-98-9
White orthorhombic
crystal
117.49
200
Melting Point: 65. 6 to
439
Not available
1.95
-5.84
7601-89-0
White orthorhombic
deliquescent crystal
122.44
2,096
Melting Point: 482
Not available
2.52
-7.18
Potassium
Perchlorate
7778-74-7
Colorless
orthorhombic crystal
or white crystalline
powder
138.55
15
Melting Point: 400
Not available
2.53
-7.18
Perchloric Acid
7601-90-3
Colorless liquid
100.47
Miscible in cold water
Melting Point: -112
Boiling Point: 19
6.8
1.664
-4.63
Notes: g/mol - grams per mole; g/L - grams per liter; mg/L - milligrams per liter; °C - degrees Celsius; mm Hg - millimeters of mercury.
What are the environmental impacts of perchlorate?
Perchlorate is highly soluble, relatively stable
and mobile in water. As a result, perchlorate
plumes in ground water can be extensive. For
example, the perchlorate plume at a former
safety flare site (the Olin Flare Facility) in
Morgan Hill, California, extends more than 9
miles (EPA 2009a; ITRC 2005).
Perchlorate compounds and the perchlorate
anion do not volatilize from water to air (EPA
IRIS 2005; ITRC 2005).
High concentrations of perchlorate have
primarily been detected at current and Formerly
Used Defense Sites historically involved in the
manufacture, testing, and disposal of
ammunition and rocket fuel (ITRC 2005).
Types of military and defense-related facilities
with known releases include missile ranges and
missile/rocket manufacturing facilities. However,
due to unavailable site specific documentation
and historical uncertainties, it is generally
difficult to determine which specific military sites
have known perchlorate releases (ITRC 2005).
In addition, the past disposal of munitions in
either burial pits or by open burning and open
detonation has the potential to result in releases
to the environment. The amount of perchlorate
released can vary depending on the length of
use and types of munitions disposed (ITRC
2005).
Recent surveys have detected perchlorate in
food crops and milk (FDA 2008).
Perchlorate has been detected in the ground
water at 54 federal facilities and 29 private
(Superfund or RCRA) sites in 26 states. (EPA
FFRRO 2011).
What are the health effects of perchlorate?
Primary pathways for human exposure to
perchlorate are ingestion of food and
contaminated drinking water (EPA FFRRO
2005).
At high enough exposures, perchlorate can
interfere with iodide uptake into the thyroid
gland, disrupting the functions of the thyroid and
potentially leading to a reduction in the
production of thyroid hormones. Thyroid
hormones play an important role in regulating
metabolism. Thyroid hormones are critical for
normal growth and development in fetuses,
infants, and young children (MAS 2005).
Potassium perchlorate was historically used to
treat hyperthyroidism and Grave's Disease
because of its ability to inhibit thyroid iodide
uptake (MAS 2005).
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Technical Fact Sheet - Perchlorate
What are the health effects of perchlorate? (continued)
Studies conducted on rodents showed that
perchlorate concentrations below that required
to alter thyroid hormone equilibrium is unlikely to
cause thyroid cancer in human beings (EPA
IRIS 2005).
The chronic oral reference dose (RfD) is 0.0007
milligrams per kilogram body weight per day.
(Note: A reference dose is an estimate [with
uncertainty spanning perhaps an order of
magnitude] of a daily oral exposure to the
human population [including sensitive
subgroups] that is likely to be without
appreciable risk of deleterious effects over a
lifetime) (EPA IRIS 2005).
Short-term exposure to high doses may cause
eye and skin irritation, coughing, nausea,
vomiting, and diarrhea (NIOSH 2007).
Are there any federal and state guidelines and health standards
for perchlorate?
EPA has decided to regulate perchlorate under
the Safe Drinking Water Act. EPA has initiated
the process of proposing a national primary
drinking water regulation (EPA 2011).
EPA established an Interim Drinking Water
Health Advisory of 15 micrograms per liter (ug/L)
in water (EPA 2009b).
The Office of Solid Waste and Emergency
Response (OSWER) has established a
preliminary remediation goal (PRG) at National
Priority List sites of 15 ug/L. PRGs are
developed based on readily available
information and are modified, as necessary,
before final cleanup goals are established,
based on information that becomes available
during the remedial investigation/ feasibility
study (EPA 2009b).
Numerous sates have promulgated enforceable
standards for perchlorate in drinking water. For
example, Massachusetts (2 ug/L) and California
(6 ug/L) have established enforceable standards
for perchlorate in drinking water (CDPH 2010;
Massachusetts DEP 2006).
California EPA released Draft California Human
Health Screening Levels (CHHSLs) for
Perchlorate. The draft CHHSLs for perchlorate is
28 parts per million (ppm) soil for residential
property and 350 ppm soil for
commercial/industrial property (Cal EPA 2009).
Certain states have also developed advisory
levels or health-based goals ranging from 4 to
51 ug/L (ITRC 2005).
What detection and site characterization methods are available
for perchlorate?
The following methods can be used to analyze
for perchlorate in drinking water, ground water,
surface water, and irrigation water:
• EPA Method 314.0—Ion Chromatography
(EPA OGWDW 2011).
• EPA Method 314.1—Inline Column
Concentration/Matrix Elimination Ion
Chromatography with Suppressed
Conductivity Detection (EPA OGWDW 2011).
• EPA Method 332.0—Ion Chromatography with
Suppressed Conductivity and Electrospray
lonization/Mass Spectrometry (EPA FFRRO
2005).
• EPA Method 331.0—Liquid
Chromatography/Electrospray lonization/
Mass Spectrometry (EPA OGWDW 2011).
• EPA Method 6850—High Performance Liquid
Chromatography/Electrospray lonization/Mass
Spectrometry (EPA 2007).
• EPA Method 6860—Ion Chromatography/
Electrospray lonization/Mass Spectrometry
(EPA 2007).
The presence of high amounts of other anions,
such as chloride, sulfate, or carbonate may
interfere with the analysis of perchlorate (EPA
1999).
Researchers have demonstrated the ability to
distinguish man-made and natural sources of
perchlorate using chlorine and oxygen stable
isotope analysis (Bohlke et al. 2005).
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Technical Fact Sheet - Perchlorate
What technologies are being used to treat perchlorate?
Ex Situ Treatment
• Ion exchange using perchlorate-selective or
nitrite-specific resins (Boodoo 2003; EPA
FFRRO 2005; GWRTAC 2001).
• Bioremediation using packed-bed or fluidized-
bed bioreactors (EPA FFRRO 2005;
GWRTAC 2001; Hatzinger 2005).
• Membrane technologies (electrodialysis and
reverse osmosis) (EPA FFRRO 2005;
GWRTAC 2001; ITRC 2005).
• Liquid phase carbon adsorption using granular
activated carbon (GAG) to remove low levels
of perchlorate; pretreatment may be
necessary to prepare GAG for perchlorate
removal (EPA FFRRO 2005; GWRTAC 2001;
ITRC 2005).
In Situ Treatment:
• Bioremediation using perchlorate-selective
microbes (EPA FFRRO 2005; GWRTAC
2001; ITRC 2005).
• Permeable reactive barrier (EPA FFRRO
2005; GWRTAC 2001; ITRC 2005).
• Phytoremediation may also be used, although
the mechanism of phytoremediation of
perchlorate is yet to be established (EPA
FFRRO 2005; GWRTAC 2001).
Where can I find more information about perchlorate?
Boodoo, F. 2003. POU/POE Removal of
Perchlorate. Water Conditioning & Purification.
Pages 1-4.
Bohlke, J. K., N.C. Sturchio, B. Gu, J. Horita,
G.M. Brown, W.A. Jackson, J. Batista, and P.B.
Hatzinger. 2005. Perchlorate isotope forensics.
Anal. Chem., 77, 7838-7842.
California Department of Public Health (CDPH).
2011. Perchlorate in Drinking Water.
www.cdph.ca.gov/certlic/drinkingwater/Pages/Pe
rchlorate.aspx
California Environmental Protection Agency (Cal
EPA. 2009. California Human Health Screening
Levels for Perchlorate.
Food and Drug Administration (FDA). 2008. U.S.
Food and Drug Administration's Total Diet
Study: Dietary intake of Perchlorate and Iodine.
Ground Water Remediation Technologies
Analysis Center (GWRTAC). 2001. Technology
Status Report: Perchlorate Treatment
Technologies. 1st edition.
Hatzinger, P.B. 2005. Perchlorate
Biodegradation for Water Treatment.
Environmental Science & Technology. Vol. A.
Pages 239-247.
Interstate Technology Regulatory Council
(ITRC). 2005. Perchlorate: Overview of Issues,
Status, and Remedial Options.
www.itrcweb.org/Documents/PERC-1.pdf
Massachusetts Department of Environmental
Protection (DEP). 2006. Perchlorate
Information.www.mass.gov/dep/water/drinking/p
ercinfo.htm#stds
Mendiratta, S.K., R.L. Dotson, and R.T. Brooker.
1996. Kirk-Othmer Encyclopedia of Chemical
Technology. Vol. 18. Pages 157-170.
National Research Council of the National
Academies (NAS). 2005. "Health Implications of
Perchlorate Ingestion."
www.nap.edu/catalog.php7record id=11202.
National Institute for Occupational Safety and
Health (NIOSH). 2007.
www.cdc.gov/niosh/ipcs/icstart.html
Rao, B., Anderson, T. A., Orris, et al. 2007.
Widespread natural perchlorate in unsaturated
zones of the Southwest United States.
Environmental Science & Technology. 41 (13),
4522 -4528,2007.
U.S. Environmental Protection Agency (EPA).
1999. Method 314.0 Determination of
Perchlorate in Drinking Water Using Ion
Chromatography. Revision.
EPA. 2007. New Test Methods On-line.
www. e pa. g o v/e pawaste/h aza rd/testm eth ods/sw
846/new meth.htm
EPA 2009a. Region 9. Perchlorate in the Pacific
Southwest.
www.epa.gov/region9/toxic/perchlorate/per ca.h
tml#olin
EPA 2009b. Revised Assessment Guidance for
Perchlorate.
www.epa.gov/fedfac/documents/perchlorate me
mo 01-08-09.pdf
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Technical Fact Sheet - Perchlorate
Where can I find more information about perchlorate? (continued)
EPA. 2011. Drinking Water Contaminants.
Unregulated. Perchlorate.
http://water.epa.gov/drink/contaminants/unregul
ated/perchlorate.cfm
EPA Federal Facilities Restoration and Reuse
Office (EPA FFRRO). 2005. Perchlorate
Treatment Technology Update - Federal
Facilities Forum Issue Paper. EPA 542-R-05-
015.
EPA FFRRO. 2011. Perchlorate and Other
Emerging Contaminants.
www.epa.gov/fedfac/documents/emerging cont
aminants.htm.
EPA Integrated Risk Information System (IRIS).
2005. "Perchlorate and Perchlorate Salts."
www.epa.gov/iris/subst/1007.htm.
EPA Office of Groundwater and Drinking Water
(OGWDW). 2011.
www.epa.gov/safewater/methods/analyticalmeth
ods ogwdw.html
U.S. Government Accountability Office (GAO).
2005. Perchlorate: A System to Track Sampling
and Cleanup Results is Needed. GAO-05-462.
Additional information on perchlorate can be found at EPA's www.cluin.org/perchlorate.
Contact Information
If you have any guestions or comments on this fact sheet, please contact: Mary Cooke, FFRRO, by phone at
(703) 603-8712 or by email at cooke.maryt@epa.gov.
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