Stable Carbon Isotope Biogeochemistry of a Shallow Sand Aquifer Contaminated with Fuel Hydrocarbons
Ground-water chemistry and the stable C isotope composition (δ13C(DIC)) of dissolved inorganic C (DIC) were measured in a sand aquifer contaminated with JP-4 fuel hydrocarbons. Results show that ground water in the upgradient zone was characterized by DIC content of 14-20 mg C/L and δ13C(DIC) values of -11.3‰ to -13.0‰. The contaminant source zone was characterized by an increase in DIC content (12.5 mg C/L to 54 mg C/L), Ca, and alkalinity, with a significant depletion of 13C in δ13C(DIC) (-11.9‰ to -19.2‰). The source zone of the contaminant plume was also characterized by elevated levels of aromatic hydrocarbons (0 μg/L to 1490 μg/L) and microbial metabolites (aromatic acids, 0 μg/L to 2277 μg/L), non-detectable dissolved O2, NO3 and SO4. Phospholipid ester-linked fatty acid analyses suggest the presence of viable SO4-reducing bacteria in ground water at the time of sampling. The ground-water chemistry and stable C isotope composition of ground-water DIC are interpreted using a chemical reaction model involving rainwater recharge, contributions of CO2 from soil gas and biodegradation of hydrocarbons, and carbonate dissolution. The major-ion chemistry and δ13C(DIC) were reconciled, and the model predictions were in good agreement with field measurements. It was concluded that stable C isotope measurements, combined with other biogeochemical measures can be a useful tool to monitor the dominant terminal electron-accepting processes in contaminated aquifers and to identify mineralogical, hydrological, and microbiological factors that affect δ13C of dissolved inorganic C.
J. Fang et al., "Stable Carbon Isotope Biogeochemistry of a Shallow Sand Aquifer Contaminated with Fuel Hydrocarbons," Applied Geochemistry, vol. 15, no. 2, pp. 157-169, Elsevier, Feb 2000.
The definitive version is available at https://doi.org/10.1016/S0883-2927(99)00037-2
Geosciences and Geological and Petroleum Engineering
United States. Environmental Protection Agency
Strategic Environmental Research and Development Program (U.S.)
Keywords and Phrases
Carbon Isotope; Environmental Monitoring; Hydrocarbon; Marine Environment; Biogeochemistry; Carbon; Groundwater Pollution; Isotopic Composition; Sand
International Standard Serial Number (ISSN)
Article - Journal
© 2000 Elsevier, All rights reserved.