Measurement error and spatial variability effects on characterization of volatile organics in the subsurface

Soil at a former land treatment facility for waste oils and solvents was intensively studied using two different methods to determine if volatile organic compounds (VOC) were present. The results showed that on-site VOC concentrations obtained using heated headspace'gas chromatography were approximately 10 times higher than off-site VOC measurements obtained using purge-and-trap gas chromatography mass spectrometry method. It is concluded that cost-effective field analyses can be more effective when sample density is large.