Soil pore-gas sampling by photoacoustic radiometry
Concentrations of volatile organics in a soil pore-gas plume were measured using a commercially available multigas monitor. The monitor is a photoacoustic radiometer (PAR) controlled by an on-board, programmable microprocessor. The measurements determine the extent and location of the vapor plume in the subsurface. At least twelve wells surrounding the sources are measured quarterly. The sources are located in former liquid chemical waste disposal pits and shafts at Los Alamos National Laboratory. The primary constituents of the plume are 1,1,1 trichloroethane (TCA), trichloroethene (TCE), and tetrachloroethene or perchloroethene or perchloroethene (PCE). Four quarters of data are presented for TCA. All were used primarily as solvents and degreasers. Previously the composition of the vapor plume was determined by Gas Chromatography Mass Spectrometer GCMS methods. Photoacoustic radiometry and gas chromatography are discussed giving the advantages and disadvantages of each method, although in this program they are basically complementary. Gas chromatography is a more qualitative method to determine which analytes are present and the approximate concentration. Photoacoustic radiometry, to function well, requires foreknowledge of constituents and serves best to determine how much is present. Measurements are quicker and more direct with photoacoustic methods. Once the constituents to be measured are known, the cost to monitor is much less using photoacoustics, and the results are available more quickly.
- Research Organization:
- Los Alamos National Lab., NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 10194248
- Report Number(s):
- LA-UR-94-3483; CONF-9411144-1; ON: DE95002717
- Resource Relation:
- Conference: Optical sensing for environmental and process monitoring,McLean, VA (United States),7-10 Nov 1994; Other Information: PBD: [1994]
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
54 ENVIRONMENTAL SCIENCES
47 OTHER INSTRUMENTATION
ORGANIC COMPOUNDS
ENVIRONMENTAL TRANSPORT
PLUMES
MONITORING
VOLATILE MATTER
SOILS
OPTICAL PROPERTIES
052002
540220
440600
WASTE DISPOSAL AND STORAGE
CHEMICALS MONITORING AND TRANSPORT
OPTICAL INSTRUMENTATION