Speciation of subsurface contaminants by cone penetrometry gas chromatography mass spectrometry

A thermal extraction cone penetrometry gas chromatography/mass spectrometry system (TECP GC/MS) has been developed to detect subsurface contaminants i n situ. The TECP can collect soil-hound organics up to depths of 30 m. In c ontrast to traditional cone penetrometer sample collectors, the TECP extrac ts organics from soil without bringing the soil to the surface or into a co llection chamber. Results show that polychlorinated biphenyls, polycyclic a romatic hydrocarbons (PAHs), chlorinated pesticides, and explosives can be recovered (60-95%) from wet or dry soil, with extraction efficiency compoun d-specific. The data are in remarkable agreement with closed cell thermal d esorption (TD) experiments, where no organics are lost to the environment d uring heating. TECP GC/MS results also compare favorably with solvent-extra cted GC/MS analyses and can be used to delineate the presence and extent of contamination at hazardous waste sites. Data illustrating TECP dependence on probe temperature and soil moisture as well as carrier gas linear veloci ty and volume (modified Reynolds number) are shown along with sample analys is data from two hazardous waste-sites. The total ion and reconstructed ion current chromatograms are shown for PAHs collected by TECP from a coal tar contaminated soil obtained at a manufactured gas plant in Massachusetts. T ECP and TD results are within 15% for nonvolatile PAHs and within 50% of th e solvent-extracted data.