EXTRACTION METHODS FOR RECOVERY OF VOLATILE ORGANIC-COMPOUNDS FROM FORTIFIED DRY SOILS

Recovery of 8 volatile organic compounds (VOCs) from dry soils, each f ortified at 800 ng/g soil, was studied in relation to the extraction m ethod and time of extraction. Extraction procedures studied on 2 desic cator-dried soils were modifications of EPA low- and high-level purge- and-trap extractions (SW-846 Method 5030A): treatment 1, unmodified lo w-level procedure; treatment 2, 18 h water pre-soak followed by low-le vel procedure; treatment 3, 24 h methanol extract at room temperature followed by high-level procedure; and treatment 4, 24 h methanol extra ct at 65 degrees C followed by high-level procedure, VOC recoveries fr om replicate soil samples increased in the treatment order 1 through 4 , With Charleston soil (8% clay and 3.8% organic carbon), highly signi ficant differences (p less than or equal to 0.001) in recoveries among treatments were observed for trichloroethene (TCE), tetrachloroethene (PCE), toluene, ethylbenzene, and o-xylene, with 2- to 3-fold increas ed recoveries between treatments 1 and 3, With Hayesville soil (32% cl ay and 0.2% organic carbon), significant improvements (p less than or equal to 0.05) in recoveries of toluene, ethylbenzene, o-xylene, 1,1,1 -trichloroethane, TCE, and PCE were observed for heated methanol (trea tment 4) rather than water extraction (treatment 1), but the increases were less than 2-fold.