xvEPA
     United States
     Environmental Protection
     Agency
    Technical  Fact  Sheet  -
                         1,4-Dioxane
                                                                            May 2012
                                                    TECHNICAL FACT SHEET - 1,4-DIOXANE
 At  a  Glance

 *  Flammable liquid and a fire hazard.
     Potentially explosive if exposed to
     light or air.
 *  Found at many federal facilities
     because of its widespread use as a
     stabilizer in chlorinated solvents,
     paint strippers, greases, and
     waxes.
 *  Short-lived  in the atmosphere, may
     leach readily from soil to ground
     water, migrates rapidly in ground
     water, and is relatively resistant to
     biodegradation in the subsurface.
 *  Classified as "likely to be
     carcinogenic to humans" by all
     routes of exposure.
 *  Contact may cause eye and skin
     irritation and burns, coughing, or
     shortness of breath.
 *  No federal drinking water standards
     have been established. Many
     states and EPA regions have set
     guidelines and action levels.
 *  Modifications to existing sample
     preparation procedures may be
     needed to achieve the increased
     sensitivity needed for dioxane
     detection. High-temperature
     sample preparation techniques
     improve the recovery of dioxane.
 *  Common treatment technologies
     include advanced oxidation
     processes and ex situ
     bioremediation.
                                      Introduction
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 1,4-dioxane, including
physical and chemical properties; environmental and health impacts;
existing federal and state guidelines; detection and treatment methods;
and additional sources of information.

1,4-Dioxane is a probable carcinogen and has been found in ground
water at sites throughout the United States. The physical and chemical
properties and behavior of 1,4-dioxane create challenges for its
characterization and treatment. It is highly mobile and has not been
shown to readily biodegrade in the environment. This fact sheet  is
intended for use by site managers faced with addressing 1,4-dioxane at
cleanup sites or in drinking water supplies and for those in a position to
consider whether 1,4-dioxane should be added to the analytical suite for
site investigations.

What is 1,4-Dioxane?

»>   1,4-Dioxane is a synthetic industrial chemical that is completely
    miscible in water (EPA 2006).
»>   Synonyms include dioxane, dioxan, p-dioxane, diethylene dioxide,
    diethylene oxide, diethylene ether, and glycol ethylene ether
    (Mohr2001).
»>   1,4-Dioxane is unstable at elevated temperatures and pressures and
    is potentially explosive if exposed to light or air (Alexeeff 1998).
»>   It is used as a stabilizer for chlorinated solvents such as 1,1,1-
    trichloroethane (TCA); a solvent for impregnating cellulose acetate
    membrane filters; a wetting and dispersing agent in textile
    processes; and as a laboratory cryoscopic solvent for molecular
    mass determinations (ATSDR 2007;  EPA 2006).
»>   It is used in many products, including paint strippers, dyes, greases,
    varnishes, and waxes. 1,4-Dioxane is also  found as an impurity in
    antifreeze and aircraft deicing fluids and in  some consumer products
    (deodorants, shampoos, and cosmetics) (ATSDR 2007; EPA 2006;
    Mohr2001).
»>   1,4-Dioxane is a likely contaminant at many federal facilities  because
    of its widespread use.
»>   Residues may be present in manufactured food additives, 1,4-
    dioxane-containing food packaging materials, or on food crops
    treated with pesticides that contain 1,4-dioxane (such as, vine-
    ripened tomatoes) (DHHS 2011).
»>   It is also a by-product in the manufacture of polyethylene
    terephthalate (PET) plastic and is used as a purifying agent in the
    manufacture of Pharmaceuticals (Mohr2001).
United States
Environmental Protection Agency
       Office of Solid Waste and
       Emergency Response (5106P)

             1
EPA 505-F-11-004
       May 2012

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  Technical Fact Sheet - 1,4-Dioxane
What is 1,4-Dioxane? (continued)
                      Exhibit 1: Physical and Chemical Properties of 1,4-Dioxane
                                    (ATSDR2007; EPA IRIS 2010)
Property
CAS Number
Physical Description (physical state at room temperature)
Molecular weight (g/mol)
Water solubility (mg/L at 25°C)
Boiling point (°C)
Vapor pressure at 25°C (mm Hg)
Specific gravity
Octanol-water partition coefficient (log Kow)
Organic carbon partition coefficient (log Koc)
Henry's law constant (atm m3/mol)

000123-91-1
Flammable liquid with a faint, pleasant odor
88.10
Soluble in water
101. 1 "Cat 760 mm Hg
40
1.033
-0.27
1.23
4.80 X10'6
       Notes: g/mol - grams per mole; mg/L - milligrams per liter; °C - degrees Celsius; mm Hg - millimeters of mercury;
       atm m3/mol - atmosphere-cubic meters per mole.

What are the environmental  impacts of 1,4-Dioxane?
    1,4-Dioxane is typically found at solvent release
    sites and PET manufacturing facilities (Mohr
    2001).
    It is short-lived in the atmosphere, with a 6- to 10-
    hour half-life (Mohr2001). Breakdown products
    include aldehydes and ketones.
    It may migrate rapidly in ground water, ahead of
    other contaminants, and does not volatilize rapidly
    from surface water bodies (EPA 2006).
It is weakly retarded by sorption to soil particles
and may move rapidly from soil to ground water
(EPA 2006).
It is relatively resistant to biodegradation and does
not bioconcentrate in the food chain (ATSDR
2007; Mohr 2001).
It has been identified at 31 of the 1,689 sites on
EPA's National Priorities List (NPL); it may be
present (but samples were not analyzed for it) at
many other sites (ATSDR 2007).
What are the health effects of 1,4-Dioxane?
    Potential exposure could occur during
    production and use of 1,4-dioxane as a stabilizer
    or solvent (DHHS 2011).
    Exposure may occur through inhalation of
    vapors, ingestion of contaminated food and
    water, or dermal contact (DHHS 2011).
    Inhalation is the most common route of human
    exposure; it is also readily adsorbed through the
    lungs, skin, and gastrointestinal tract.
    Distribution is rapid and  uniform in lung, liver,
    kidney, spleen, colon, and skeletal muscle tissue
    (ATSDR 2007).
    Workers at industrial sites are at greatest risk of
    repeated inhalation exposure (DHHS 2011).
    Short-term exposure may result in irritation of
    the eyes, nose, throat, and lungs; possible
    drowsiness; vertigo; headache; and anorexia
    (ATSDR 2007).
  Chronic exposure may result in dermatitis,
  eczema, drying and cracking of skin, and liver
  and kidney damage (ATSDR 2007; EPA OSW
  1996).
  1,4-Dioxane is weakly genotoxic and
  reproductive effects are unknown; however, a
  developmental study on rats indicated that the
  developing fetus  may be a target of
  toxicity (ATSDR 2007; EPA IRIS 2010).
  EPA has classified 1,4-dioxane as "likely to be
  carcinogenic to humans" by all routes of
  exposure (EPA IRIS 2010).
  The chronic oral reference dose (RfD) is 0.03
  milligrams per kilogram per day (EPA IRIS
  2010).

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  Technical Fact Sheet - 1,4-Dioxane
Are there any federal  and state standards and guidelines for 1,4-Dioxane?
   Water Standards and Guidelines:
   • 1,4-Dioxane may be regulated as hazardous
     waste when used as a solvent stabilizer (EPA
     OSW1996).
   • No federal drinking water standards have been
     established (DHHS 2011). However, a maximum
     contaminant level (MCL) is not necessary to
     determine a cleanup level.
   • EPA Regions 3, 6, and 9 have calculated a
     screening level of 6.1 micrograms per liter (ug/L)
     for 1,4-dioxane in tap water,  based on a 1 in 10
     lifetime excess cancer risk. This screening level
     is not enforceable but provides a useful gauge of
     relative toxicity (EPA 2011).
   • State regulators often use drinking water action
     levels and health advisories to establish site
     cleanup goals. Cleanup levels vary by state,
     ranging from 3 to 85 ug/L in drinking water or
     ground water. Only Colorado has established an
     enforceable cleanup standard: facilities must
     achieve a 6.1 ug/L level by March 2005 and a
     3.2 ug/L level by March 2012 (CDPHE 2005).
   Workplace  Exposure Limits:
   • The Occupational Safety and Health
     Administration (OSHA) airborne permissible
     exposure limit (PEL) is 360 milligrams per cubic
     meter (mg/m3) or 100 mg/L
     (NIOSH 2007; OSHA 1998).
• The American Conference of Governmental
  Industrial Hygienists (ACGIH) threshold limit
  value (TLV) for dermal exposure is 25 mg/L, and
  the recommended airborne exposure limit is 20
  mg/L averaged over an 8-hour work shift
  (ACGIH 1998; EPA OSW 1996).
• The National  Institute for Occupational Safety
  and Health (NIOSH) has set 500 mg/L as the
  concentration that is immediately dangerous to
  life or health (IDLH) and recommended 1 mg/L
  as the airborne exposure limit (NIOSH 2007).
Other Federal Standards and Guidelines:
• The Food and Drug Administration set 10 parts
  per million (ppm) as the limit for 1-4-dioxane in
  glycerides and polyglycerides for use in products
  such as dietary supplements. FDA also surveys
  raw material and products  contaminated with
  1,4-dioxane (ATSDR 2007).
• 1,4-Dioxane is exempted from tolerances for
  pesticide chemicals in or on raw agricultural
  commodities, and it has been classified as a
  toxic inert ingredient of pesticide products
  (EPA 2012).
• 1,4-Dioxane is listed as a hazardous air pollutant
  under the Clean Air Act (CAA) (EPA 2012).
• A reportable quantity of 100 pounds has been
  established under CERCLA (EPA 2012).
What detection and site characterization methods are available for
1,4-Dioxane?
   As a result of the limitations in the analytical
   methods to detect 1,4-dioxane, it has been difficult
   to identify its occurrence in the environment.
   Modifications to existing sample preparation
   procedures may be needed to achieve increased
   sensitivity for 1,4-dioxane detection (EPA 2006).
   Conventional analytical methods produced
   sensitivity levels that were about 100 times greater
   for 1,4-dioxane as compared with those for volatile
   organic compounds (VOCs) (Mohr2001).
High-temperature sample preparation techniques
improve the recovery of 1,4-dioxane. These
techniques include purging at elevated
temperature (SW-846 Method 5030C); equilibrium
headspace analysis  (SW-846 Method 5021);
vacuum distillation (SW-846  Method 8261 A); and
azeotrophic distillation (SW-846 Method 5031)
(EPA 2000, 2006).
It is recommended that ground water samples be
analyzed for 1,4-dioxane where TCA is a known
contaminant.
What technologies are being used to treat 1,4-Dioxane?
    Pump-and-treat (P&T) remediation is potentially
    applicable when the ex situ treatment is tailored for
    the unique properties of 1,4-dioxane
    (EPA 2006).
Commercially available advanced oxidation
processes (AOP) using hydrogen peroxide with
ultraviolet (UV) light or ozone is used to treat 1,4-
dioxane (EPA 2006; EPA OSW 1996).

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  Technical Fact Sheet - 1,4-Dioxane
What technologies are being used to treat 1,4-Dioxane? (continued)
    Ex situ bioremediation using a fixed-film, moving-
    bed biological treatment system is also used to
    treat 1,4-dioxane (EPA 2006).
    Phytoremediation is being explored as a means to
    remove the compound from shallow ground water.
    Research on hybrid poplars has demonstrated
    their ability to take up and effectively degrade or
    deactivate 1,4-dioxane (EPA  2001, EPA 2012).
    Microbial degradation in engineered bioreactors
    has been documented under enhanced  conditions
or where selected strains of bacteria capable of
degrading 1,4-dioxane are cultured
(EPA 2006, 2010).

Photocatalysis has been shown to remove 1,4-
dioxane in aqueous solutions (Purifies ES Inc.
2006; Vescovietal. 2010).
Other in-well combined treatment technologies
being assessed include air sparging; soil vapor
extraction; and dynamic subsurface ground water
circulation (Odah et al. 2005).
Where can  I find more information about 1,4-Dioxane?
   Agency for Toxic Substances and Disease
   Registry (ATSDR). 2007. "lexicological Profile for
   1,4-Dioxane."
   www.atsdr.cdc.gov/toxprofiles/tp187.pdf
   Alexeeff, G. 1998. Office of Environmental Hazard
   Assessment. Memorandum:  1,4-Dioxane Action
   Level.
   http://oehha.ca.gov/water/pals/pdf/PAL14DIOXAN.
   Edf
   American Conference of Governmental Industrial
   Hygienists (ACGIH). 1998. Threshold Limit Values
   (TLVs) for Chemical Substances and Physical
   Agents Biological Exposure Indices for 1998.
   Cincinnati, Ohio.
   Colorado Department of Public Health and the
   Environment (CDPHE). 2005. Regulation No 31.
   http://water.epa.gov/scitech/swguidance/standards
   /upload/2006  01  23 standards  wqslibrary  co  re
   Q31-20051231.pdf
   International Agency for Research on Cancer
   (IARC). 1999. "Re-Evaluation of Some Organic
   Chemicals, Hydrazine and Hydrogen Peroxide."
   Monographs on the Evaluation of Carcinogenic
   Risk of Chemicals to Man. Volume 71. Pages 589
   to 602.
   Mohr, T.K.G. 2001.  "Solvent Stabilizers White
   Paper." Prepublication Copy. Santa Clara Valley
   Water District of California. San Jose, California.
   National Institute for Occupational Safety and
   Health (NIOSH). 2007. "Pocket Guide to Chemical
   Hazards." Cincinnati, Ohio. Page  120.
   www.cdc.gov/niosh/docs/2005-149/pdfs/2005-
   149.pdf
    Occupational Safety and Health Administration
    (OSHA). 1998. "Occupational Safety and Health
    Standards, Toxic and Hazardous Substances." 29
    Code of Federal Regulations 1910.1000.
Odah, M.M., R. Powell, and D.J. Riddle. 2005.
"ART in-well technology proves effective in
treating 1,4-Dioxane contamination." Remediation
Journal. Volume 15 (3), Pages 51 to 64.
Purifies ES Inc. 2006. Case History:  1,4 Dioxane
Remediation 1.
www.purifics.com/solutions/pdf/Case%20History%
20-%201,4-Dioxane%201 .pdf
U.S. Department of Health and Human Services
(DHHS). 2011. 1,4-Dioxane, CAS No. 123-91-1,
Report on Carcinogens, 12th Edition.
U.S. Environmental Protection Agency (EPA)
Office of Solid  Waste (OSW). 1996. Solvents
Study. EPA 530-R-96-017, 52 pages.
EPA. 2000. "Method 8261. Volatile Organic
Compounds by Vacuum Distillation  in Combination
with Gas Chromatography/Mass Spectroscopy
(VD/GC/MS)."  In:  SW-846 Draft Update IVB.
EPA. 2001. "Brownfields  Technology Primer:
Selecting and Using Phytoremediation  for Site
Cleanup." EPA 542-R-01-006.
EPA. 2006. "Treatment Technologies for 1,4-
Dioxane:  Fundamentals  and Field Applications."
EPA 542-R-06-009.
www.epa.gov/tio/download/remed/542r06009.pdf
EPA. 2012. "1,4 Dioxane" www.clu-in.org/
contaminantfocus/default.focus/sec/1,4-
Dioxane/cat/Overview/

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 Technical Fact Sheet - 1,4-Dioxane
Where can I find more information about 1,4-Dioxane? (continued)
   EPA. 2011. Regions 3, 6, and 9. Regional
   Screening Levels Table.
   www.epa.gov/reg3hwmd/risk/human/index.htm
   EPA Integrated Risk Information System (IRIS).
   2010. "1,4-Dioxane (CASRN 123-91-1)."
   www.epa.gov/iris/subst/0326.htm
Vescovi T., H. Coleman, and R. Amal. 2010. "The
Effect of pH on UV-based advanced oxidation
technologies- 1,4-dioxane degradation." Journal of
Hazardous Materials. Volume 182. Pages 75 to
79.
Additional information on 1,4-dioxane can be found at www.cluin.org/dioxane.



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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