Differentiation of naturally-occurring vs. artificial hydrocarbons in a landfill groundwater investigation
- Law Environmental, Inc., Kennesaw, GA (United States)
Interpretation of groundwater sampling data at a large municipal/industrial landfill indicates contamination by both artificial and naturally-occurring hydrocarbons. Site hydrogeology consists of three different water bearing zones. The uppermost (shallow) aquifer is an unconfined unit consisting of silt, clay, and sand deposits. An intermediate depth semiconfined aquifer underlies the unconfined unit, and consists of a chert rubble zone and the upper portion of a fractured and solution-enhanced limestone formation. A regionally-extensive organic-rich shale underlies the semiconfined aquifer and separates it from the deep confined aquifer, which also consists of limestone. Groundwater investigations at the landfill have detected chlorinated and non-chlorinated hydrocarbons in the different aquifer intervals. Chlorinated hydrocarbons detected include tetrachloroethene, dichloroethene, and vinyl chloride and occur almost exclusively in the shallow aquifer. Aromatic hydrocarbons detected include benzene, toluene, ethylbenzene, and xylene (BTEX) and-occur in the intermediate and deep aquifers. The landfill was originally interpreted as the source of the contaminants. The observation of free-phase liquid hydrocarbons in the intermediate aquifer at the site, and high dissolved BTEX levels in the deep and intermediate aquifers upgradient of the landfill suggest that the aromatics were derived from a source other than the landfill. A potential source of BTEX contamination may be abandoned (pre-1930) natural gas wells located near the landfill. An additional BTEX source may be the organic-rich shale formation (a documented petroleum source rock).
- OSTI ID:
- 69858
- Report Number(s):
- CONF-941189-; ISBN 1-56590-016-2; TRN: IM9529%%246
- Resource Relation:
- Conference: SUPERFUND XV: 15th environmental conference and exhibition for the hazardous materials/hazardous waste management industry, Washington, DC (United States), 29 Nov - 1 Dec 1994; Other Information: PBD: 1994; Related Information: Is Part Of Superfund XV conference proceedings. Volume 2; PB: 877 p.
- Country of Publication:
- United States
- Language:
- English
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