Temporal dynamics of biogeochemical processes at the Norman Landfill site

Water Resources Research
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Abstract

The temporal variability observed in redox sensitive species in groundwater can be attributed to coupled hydrological, geochemical, and microbial processes. These controlling processes are typically nonstationary, and distributed across various time scales. Therefore, the purpose of this study is to investigate biogeochemical data sets from a municipal landfill site to identify the dominant modes of variation and determine the physical controls that become significant at different time scales. Data on hydraulic head, specific conductance, δ2H, chloride, sulfate, nitrate, and nonvolatile dissolved organic carbon were collected between 1998 and 2000 at three wells at the Norman Landfill site in Norman, OK. Wavelet analysis on this geochemical data set indicates that variations in concentrations of reactive and conservative solutes are strongly coupled to hydrologic variability (water table elevation and precipitation) at 8 month scales, and to individual eco-hydrogeologic framework (such as seasonality of vegetation, surface-groundwater dynamics) at 16 month scales. Apart from hydrologic variations, temporal variability in sulfate concentrations can be associated with different sources (FeS cycling, recharge events) and sinks (uptake by vegetation) depending on the well location and proximity to the leachate plume. Results suggest that nitrate concentrations show multiscale behavior across temporal scales for different well locations, and dominant variability in dissolved organic carbon for a closed municipal landfill can be larger than 2 years due to its decomposition and changing content. A conceptual framework that explains the variability in chemical concentrations at different time scales as a function of hydrologic processes, site-specific interactions, and/or coupled biogeochemical effects is also presented.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Temporal dynamics of biogeochemical processes at the Norman Landfill site
Series title Water Resources Research
DOI 10.1002/wrcr.20484
Volume 49
Issue 10
Year Published 2013
Language English
Publisher Wiley
Contributing office(s) National Research Program - Eastern Branch
Description 18 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Water Resources Research
First page 6909
Last page 6926
Country United States
State Oklahoma
City Norman