Determining Total Petroleum Hydrocarbons in Soil

Abstract Many state agencies, using an infrared analysis [IR], establish total petroleum hydrocarbon (TPH) levels above which soils are considered contaminated. As a result, clean closure of contaminated areas are prohibited and, in some cases, Deed Recordation required. In many instances, a fraction of the hydrocarbon observed using the IR technique is co-extracted carbohydrates, fats and proteins associated with the indigenous soil humus. Test results from the field biodegradation studies reveal TPH analysis by gas chromatographic [GC] technique provide an accurate index to treatment efficiencies and treatment methods establishing petroleum residual levels. Significant decrease in TPH-GC with time corresponds to a significant decrease in the dry weight loss on ignition [LOI] quantified at 150°, 200° and 250° C. The authors conclude complete analyses [IR and GC] are required to avoid improperly characterizing the source and level of TPH contamination.