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

Diffusion Samplers

Diffusion samplers can be used to sample halogenated alkanes in water. Halogenated alkanes are volatile; therefore, diffusion sampling devices also should be effective for most of these chemicals in soil gas.

Standard Laboratory Methods

Most of the chlorinated alkanes can be detected using standard SW-846 volatile organic methods or Contract Laboratory Program methods. Before ordering the analysis, check to see if the chemical is listed; if it is not, it will show up as a tentatively identified compound (TIC). The laboratory might report TICs only when specifically requested.

While listed as detectable by SW-846 method 8260, 1,2-dichloropropane, 1,2-dibromoethane, and 1,2-dibromo-3-chloropropane have low required risk-based detection limits that are not routinely obtained using this method. Method 8011 is specifically for 1,2-dibromoethane and 1,2-dibromo-3-chloropropane in water, and it can obtain the required detection limits.

Field Screening Methods

Field GC and GC/MS are appropriate for most of the halogenated alkanes. Standards should be run to verify detection limits.

Many of the halogenated alkanes are detectable using instruments that have a photoionization detector (PID); however, some of them have ionization potentials above 11.7 eV. The ionization potential of the individual chemicals should be checked before using PID-based instruments. Three lamps (9.5 eV, 10.2 eV, and 11.7 eV) are available for PID instruments, and the chemical of concern's ionization potential should be matched with the appropriate lamp.

Some of the halogenated alkanes can be detected using gas detection tubes. While these tubes are useful when the site has a single known contaminant, they generally are not compound specific, and in the presence of mixtures will provide only a total number.