U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

Dense Nonaqueous Phase Liquids (DNAPLs)

Detection and Site Characterization

Halogenated Alkanes


1,1,1-Trichloroethane(1,1,1-TCA) is a volatile halogenated organic compound and as such is subject to most standard characterization and analytical techniques used on this class of chemicals. Methods such as vertical profiling, dyes, and standard GC/MS are discussed in the main section for DNAPLs detection and site characterization.

Commercial grades of this compound usually contain some inhibitor, such as nitromethane, methyl ethyl ketone, toluene, 1,4-dioxane, butylene oxide, 1,3-dioxolane, or secondary butyl alcohols (ATSDR 2006). Some of these inhibitors, such as 1,4-dioxane, are contaminants of concern in their own right and might not be detected using routine GC/MS methods.

Diffusion Samplers

1,1,1-TCA contaminated groundwater can be sampled by Diffusion Samplers (ITRC 2004).

Laboratory Methods

Analysis of 1,1,1-TCA can be performed using standard analyses such as SW-846 methods 8021bAdobe PDF Logo, 8260bAdobe PDF Logo, and 8260cAdobe PDF Logo.The Agency for Toxic Substances and Disease Registry's toxicological profile for 1,1,1-TCA contains a discussion of laboratory analytical methodsAdobe PDF Logo for this compound.

Field Screening Methods

1,1,1-TCA should be detectable using headspace analysis with a field GC. Standards should be run to verify detection limit requirements. If the GC uses a photoionization detector (PID) instead of an electron capture detector (ECD), the lamp must be 11.7 eV as the standard 10.6 eV lamp will not ionize 1,1,1-TCA (ionization potential of 11). This would also be true for an organic vapor analyzer using a PID (EPA 1994 and HNU 1997).


Photoionization Characteristics of Selected CompoundsAdobe PDF Logo
HNU Systems, Inc., 12 pp, 1997

Standard Operating Procedure# 2114: Photoionization Detector HNUAdobe PDF Logo
U.S. EPA, Emergency Response Team, 16 pp, 1994

This document contains an extensive list of chemicals with their photoionization potentials.

Technical and Regulatory Guidance for Using Polyethylene Diffusion Bag Samplers to Monitor Volatile Organic Compounds in GroundwaterAdobe PDF Logo
Interstate Technology & Regulatory Council (ITRC). DSP-3, 78 pp, 2004

Test Methods for Evaluating Solid Waste, Physical/Chemical Methods
U.S. EPA, SW-846 on line

For Further Information

Quantitative Determination of 1,4-Dioxane and Tetrahydrofuran in Groundwater by Solid Phase Extraction GC/MS/MS
Isaacson, C., T.K. Mohr, and J.A. Field.
Environmental Science & Technology 40(23):7305-7311(2006)
View abstract