ROUND-ROBIN STUDY OF PERFORMANCE EVALUATION SOILS VAPOR-FORTIFIED WITH VOLATILE ORGANIC-COMPOUNDS

Three soils were vapor-fortified with volatile organic compounds (VOCs) to produce materials suitable for performance evaluation and related quality assurance/quality control (QA/QC) functions. Twelve laboratories analyzed two independently prepared sets of three different soil subsamples fortified with trans- 1,2-dichloroethylene (TDCE), trichloroethylene (TCE), benzene (Ben), and toluene (Tol). Analyte concentration estimates were reported for each soil subsample following a methanol extraction, purge- and-trap gas chromatography/mass spectrometry analysis (Method 8240, SW846). Relative standard deviations within individual soils ranged from 8.5 to 28.2%, with a pooled standard deviation of < 13%. The best precision was for Ben (pooled RSD, 9.0%), while TDCE showed the greatest overall un certainty (pooled RSD, 20.3%). These results confirm that vapor fortification, followed by confinement in sealed glass ampules, is a precise means of preparing and storing VOC-contaminated soil subsamples for use in quality assurance programs.