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Advances in Environmental Research Volume 9, Number 2, June 2020 , pages 123-133 DOI: https://doi.org/10.12989/aer.2020.9.2.123 |
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Water table: The dominant control on CH₄ and CO₂ emission from a closed landfill site |
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Arthur N. Nwachukwu and Nkechinyere V. Nwachukwu
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| Abstract | ||
| A time series dataset was conducted to ascertain the effect of water table on the variability in and emission of CH₄ and CO₂ concentrations at a closed landfill site. An in-situ data of methane/carbon dioxide concentrations and environmental parameters were collected by means of an in-borehole gas monitor, the Gasclam (Ion Science, UK). Linear regression analysis was used to determine the strength of the correlation between ground-gas concentration and water table. The result shows CH₄ and CO₂concentrations to be variable with strong negative correlations of approximately 0.5 each with water table over the entire monitoring period. The R² was slightly improved by considering their concentration over single periods of increasing and decreasing water table, single periods of increasing water table, and single periods of decreasing water table; their correlations increased significantly at 95% confidence level. The result revealed that fluctuations in groundwater level is the key driving force on the emission of and variability in ground-gas concentration and neither barometric pressure nor temperature. This finding further validates the earlier finding that atmospheric pressure – the acclaimed major control on the variability/migration of CH₄ and CO₂ concentrations on contaminated sites, is not always so. | ||
| Key Words | ||
| asphyxiant; explosive mixture; Gasclam; greenhouse gas; risk prediction | ||
| Address | ||
| Arthur N. Nwachukwu: 1.) Williamson Research Centre for Molecular Environmental Sciences School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, M13 9PL, U.K. 2.) Department of Physics, Alex Ekwueme Federal University, Ndufu-Alike Ikwo, Ebonyi state, Nigeria Nkechinyere V. Nwachukwu: Department of Community Medicine, Alex Ekwueme Federal University Teaching Hospital, Abakaliki, Nigeria | ||
