Modular system for survey and long-term monitoring of soil CO2 exchange and CH4 effluxes

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The measurement of CO2 and CH4 fluxes using a variety of techniques, including CO2 and CH4 flux chambers, has become an integral part of global change studies. However, these methods have only found very limited use in the field of contaminant hydrogeology. With this proposal, we are requesting equipment to extend our existing single chamber CO2 flux system to facilitate simultaneous long-term analysis of CO2-soil gas exchange at eight observation points and to concurrently measure CH4 emissions both in survey and long-term mode. Simultaneous analysis at multiple locations is necessary to adequately account for the spatial and temporal variability of CO2 and CH4 fluxes at a site. The chamber system will be used to quantify the exchange of CO2 between soils/sediments and the atmosphere for a variety of applications of relevance to Canada's resource and environmental industry including sites contaminated with hydrocarbons and biofuel, waste rock and tailings, landfill sites, and natural environments affected by soil anaerobiosis. At sites contaminated with hydrocarbons and biofuel, it is anticipated that CO2 and CH4 flux measurements will help to delineate the extent of contaminant source zones, constrain depth-integrated contaminant degradation rates, and reveal the potential for CH4 release to the atmosphere or ingress into nearby structures. At mine sites, CO2 flux measurements will provide an indirect means to determine tailings and waste rock weathering rates. At mine sites with tailings or waste rock that contain ultra-mafic minerals, the measurements will reveal if this type of material is capable of directly sequestering CO2 from the atmosphere. At landfill sites, the system will provide a quantitative measure of CO2 and CH4 emissions from the facilities. The equipment will also be used to evaluate the CH4:CO2 ratio at natural sites with high CH4 effluxes caused by soil anaerobiosis. The flux chamber system will benefit the research programs of the applicants by ideally complementing current expertise in the analysis of soil gas concentrations, moisture contents, isotopic analyses, as well as mineralogical, and microbiological studies.