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Anal Chem

Title:		Effectiveness of Purge-and-Trap for Measurement of Volatile Organic Compounds in Aged Soils
Author(s):		Askari MD; Maskarinec MP; Smith SM; Beam PM; Travis CC;
Address:		"University of Tennessee, Knoxville, Tennessee 37996, EM-451, 1000 Independence Avenue, U.S. Department of Energy, Washington, D.C. 20585, and Chemical and Analytical Sciences and Health Sciences Research Divisions, Oak Ridge National Laboratories, Oak Ridge, Tennessee 37830"
Journal Title:		Anal Chem
Year:		1996
Volume:		68
Issue:		19
Page Number:		3431 - 3433
DOI:		10.1021/ac960009c
ISSN/ISBN:		0003-2700 (Print) 0003-2700 (Linking)
Abstract:		"The U.S. EPA-recommended method for measurement of trace levels of volatile organic compounds (VOCs) in soil, purge-and-trap, measures the readily desorbable organic contaminants from soil pore spaces and external soil surfaces. It does not, however, measure contamination that has diffused into internal micropores of soil matrix. Thus, the purge-and-trap method measures only a small fraction of total soil contaminants, especially in long-contaminated soils, where approximately 90-99% of contamination may be in the interior of the soil matrix. We compared three methods for determination of VOCs in aged field samples: purge-and-trap, methanol immersion, and hot solvent extraction. Hot solvent extraction proved to be much more effective than the U.S. EPA-approved purge-and-trap technique. For three long-contaminated soils containing such VOCs as trichloroethene, benzene, toluene, chloroform, methylene chloride, and cis-1,1-dichloroethylene, recovery from purge-and-trap ranged between 1.5 and 41.3% that of hot solvent extraction. Our data show that purge-and-trap may not be the best methodology for measuring soil VOCs concentrations, particularly in aged soils. It is clear from this and previous studies that the best overall choice for soil VOCs measurements is hot solvent extraction. These results also indicate the inefficiency of purge-and-trap as a method for evaluating vapor extraction remediation technology. Our results suggest that the EPA should review the use of the purge-and-trap method for measuring VOCs concentrations in soils"
Keywords:
Notes:		"PubMed-not-MEDLINEAskari, M D Maskarinec, M P Smith, S M Beam, P M Travis, C C eng 1996/10/01 Anal Chem. 1996 Oct 1; 68(19):3431-3. doi: 10.1021/ac960009c"