1,4-Dioxane

Until recently, the discovery of 1,4-Dioxane at cleanup sites often occurred well after the completion of site characterization and remedial design, complicating implementation of effective remedial measures for the compound. The possible presence of 1,4-Dioxane has not been investigated at the majority of solvent release sites due to the relatively recent development of the laboratory methods necessary to detect it at concentrations less than 100 µg/L, and to the recent and increasing awareness that it might be a contaminant of concern at solvent release sites.

Commercial laboratories report commonly analyzing for 1,4-Dioxane in water by three methods: EPA 524.2 for drinking water, and EPA 8260 and 8270 for groundwater and hazardous waste (though 524.2 and 8270 do not list 1,4-Dioxane as a target analyte). A modification to EPA 8260 has allowed lower detection limits. Determination of 1,4-Dioxane in water at low detection levels is accomplished most often using modified EPA 8270 with liquid-liquid extraction and isotope dilution by capillary column gas chromatography-mass spectrometry (GC-MS). This GC-MS method is optimized for 1,4-Dioxane as a single analyte.

In 2008, EPA released Method 522 for the Drinking Water Program. Method 522, Determination of 1,4-Dioxane In Drinking Water by Solid Phase Extraction (SPE) and Gas Chromatography/Mass Spectrometry (GC/MS) with Selected Ion Monitoring (SIM), was developed specifically to monitor for 1,4-Dioxane in drinking water and was approved to support the third cycle of the Unregulated Contaminant Monitoring Program (UCMR 3).

The purpose of this section is to identify analytical and sampling methods commonly used for detecting, measuring, and/or monitoring 1,4-Dioxane that are available on line. The intent is not to provide an exhaustive list of analytical methods, but to identify well-established, standard methods, particularly those used for environmental samples and approved by EPA. The table below summarizes these methods.

MATRIX	METHOD	INSTRUMENTATION	DETECTION LIMIT
Soil, Water	EPA SW 846 Method 8015	GC/FID	15 µg/L (MDL)
Soil, Water	EPA SW 846 Method 8240	GC/MS Purge and trap or direct injection
Soil, Water	EPA SW 846 Method 8260	GC/MS	*
Soil, Water	EPA SW 846 Method 8260 SIM	GC/MS-SIM	0.5 - 10.0 µg/L (MDL)
Soil, Water, Tissue	EPA SW 846 Method 8261	VD/GC/MS	1.1 µg/L (MDL)
Soil, Water	EPA SW 846 Method 8270	GC/MS	0.23 - 1.0 µg/L (MDL)
Soil, Water	EPA SW 846 Method 8270 SIM	GC/MS-SIM
Air	EPA Method TO-15	GC/MS
Water	EPA Method 1624 (Note compound listed as a method analyte)	ID GC/MS
Air	NIOSH 1602	GC/FID
Drinking Water	EPA Method 522	SPE, GC/MS-SIM	0.020 -0.036 µg/L (DL)
Soil, Water	EPA Method 625 (Note: compound not listed as a method analyte)	GC/MS

* When analyzed for with other chemicals of concern a purge and trap extraction method is generally the default (SW 846 5030 or 5035) when direct injection is not performed. This extraction method is inappropriate for 1,4-Dioxane and will yield a high detection limit. What is required is an extraction method for volatile, nonpurgeable, water-soluble compounds such as Azeotropic Distillation.

1,4-Dioxane in Water by Selective Ion Monitoring (SIM) Gas Chromatography/Mass Spectrometry (GC/MS): EPA CLP Method OLM03.1 (1994)
U.S. EPA Region 9, 3 pp, Revised 12/17/99.

Advisory: Active Soil Gas Investigations
California Department of Toxic Substances Control, 2015.

Appendix A to Part 136 Method 1624 Revision B-Volatile Organic Compounds by Isotope Dilution GC/MS

Determination of 1,4-Dioxane in the Cape Fear River Watershed by Heated Purge-and-Trap Preconcentration and Gas Chromatography-Mass Spectrometry
Sun, M., C. Lopez-Velandia, and D.R.U. Knappe.
Environmental Science & Technology 50(5):2246-2254(2016)

https://pubmed.ncbi.nlm.nih.gov/26829406/" target="_blank">Abstract

EDQW 1,4-Dioxane Sampling & Analysis Guidance
U.S. DoD Environmental Data Quality Workgroup, 2022

The main objective of this document is to provide guidance on selection of sampling and analysis methods for 1,4-Dioxane (1, 4-D) in aqueous matrix based on the current state of the science.

Field Demonstration and Validation of a New Device for Measuring Water and Solute Fluxes, NASA LC-34 Site
Environmental Security Technology Certification Program (ESTCP), 172 pp, 2006

ESTCP passive flux meter (PFM) demonstration and validation projects include MTBE flux measurement at Port Hueneme, perchlorate flux at the Naval Surface Warfare Center at Indianhead, and TCE flux at NASA Launch Complex 34 at Cape Canaveral.

Mass Flux Toolkit to Evaluate Groundwater Impacts, Attenuation, and Remediation Alternatives
Environmental Security Technology Certification Program (ESTCP), 2006

To help site managers and site consultants estimate mass flux and understand the uncertainty in those estimates, ESTCP has funded the development of a computerized Mass Flux Toolkit, free software that gives site personnel the capability to compare different mass flux approaches, calculate mass flux from transect data, and apply mass flux to manage ground-water plumes. The toolkit spreadsheet and associated documentation are available on the ESTCP contractor's website in a zipped file.

Method 522 Determination of 1,4-Dioxane In Drinking Water by Solid Phase Extraction (SPE) and Gas Chromatography/ Mass Spectrometry (GC/MS) with Selected Ion Monitoring (SIM)
Munch, Jean W. and Paul E. Grimmett
USEPA, EPA/600/R-08/101, 41 pp, 2008

Non-Purgeable Volatile Organic Compounds Rapidly Determined by Gas Chromatography/Mass Spectrometry Using Direct Aqueous Injection
S.M. Pyle, A.B. Marcus, L.S. Johnson.
U.S. EPA, National Exposure Research Laboratory, 1995.

Rapid Analysis of 1,4-Dioxane in Groundwater by Frozen Micro-Extraction with Gas Chromatography/Mass Spectrometry
Li, M., P. Conlon, S. Fiorenza, R.J. Vitale, and P.J.J. Alvarez.
Ground Water Monitoring & Remediation 31(4):70-76(2011)

An innovative micro-extraction of aqueous samples coupled with GC/MS in selected ion-monitoring mode analyzes for 1,4-Dioxane selectively with low ppb detection sensitivity. Freezing the aqueous sample along with the extraction solvent enhances the extraction efficiency, minimizes physical interferences, and improves sensitivity, achieving a limit of detection for dioxane to ~1.6 µg/L in a relatively small sample volume (200 µL).

Results Report for the Demonstration of No-Purge Groundwater Sampling Devices at Former McClellan Air Force Base, CA
U.S. Army Corps of Engineers Omaha District, Air Force Center for Environmental Excellence, and Air Force Real Property Agency. 79 pp, 2005

Analyses of VOCs, metals, anions, and 1,4-Dioxane levels in samples from four diffusion and two grab-type no-purge samplers were compared to those from conventional low-flow and three-well-volume purge samples.

Standard Operating Procedure for Measurement of Purgeable 1,4-Dioxane in Water by GC/MS
EPA Region 1 Office of Environmental Measurement and Evaluation SOP VOADIOX3.

Test Methods for Evaluating Solid Wastes: Physical/Chemical Methods
U.S. Environmental Protection Agency, SW-846.

Method 5030C: Purge-and-Trap for Aqueous Samples
Method 5031: Volatile, Nonpurgeable, Water-Soluble Compounds by Azeotropic Distillation
Method 5032: Volatile Organic Compounds by Vacuum Distillation
Method 5035A: Closed-System Purge-and-Trap and Extraction for Volatile Organics in Soil and Waste Samples
Method 8015C: Nonhalogenated Organics Using GC/FID
Method 8260B: Volatile Organic Compounds by Gas Chromatography/Mass Spectrometry (GC/MS)
Method 8261: Volatile Organic Compounds by Vacuum Distillation in Combination with Gas Chromatography/mass Spectrometry (VD/GC/MS)
Method 8270c: Semivolatile Organic Compounds by Gas Chromatography/mass Spectrometry (GC/MS)

Literature References

Measurement and Monitoring Technologies for the 21st Century Initiative (21M²) Literature Search
Through the Measurement and Monitoring Technologies for the 21st Century initiative, EPA's Office of Solid Waste and Emergency Response (OSWER) will identify and deploy promising measurement and monitoring technologies in response to waste management and site cleanup program needs by matching existing and emerging technologies with OSWER program and client needs.

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