Diffusion and consumption of methane in an unsaturated zone in north-central Illinois, U.S.A.

Robert G. Striegl; A. L. Ishii

doi:10.1016/0022-1694(89)90256-4

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Diffusion and consumption of methane in an unsaturated zone in north-central Illinois, U.S.A.

Robert G. Striegl·A. L. Ishii

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Abstract

The distribution of CH 4 in unsaturated glacial and eolian deposits adjacent to buried low-level radioactive waste was measured, and movement of the gas from the waste source was simulated using a two-dimensional finite-difference model for gas diffusion in the unsaturated zone. Mean P CH 4 was greatest (1.56 Pa) in a pebbly-sand deposit 11.6 m below the land surface and 12 m from the waste, and generally decreased with increased horizontal distance from the waste. Mean P CH 4 was least (0.07 Pa) at depth of 1.8 m below land surface, regardless of distance from the waste. P CH 4 at the land surface averaged 0.17 Pa. Depth versus P CH 4 profiles suggest consumption of both waste-produced and atmospheric CH 4 in the upper unsaturated zone, presumably by methanotrophic microorganisms. Numerical simulations of methane movement support the consumption observation; inclusion of a term in the model for consumption of CH 4 in the upper 2 m of the unsaturated zone resulted in simulated P CH 4 within 30% of mean P CH 4 at eleven of thirteen sampling locations. A similar fit of the data was obtained for only four locations when consumption was not considered.

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Source-reported bounding extent: 41.1487° to 41.5867° latitude; -89.861° to -89.1649° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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Robert G. Striegl, A. L. Ishii. 1989. Diffusion and consumption of methane in an unsaturated zone in north-central Illinois, U.S.A.. https://doi.org/10.1016/0022-1694(89)90256-4

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