Grantee Research Project Results
Strontium Isotopic Tracing Of Coal Bed Natural Gas Product Water To Determine Potential Beneficial Uses And Recharge Into Shallow Groundwater Systems.EPA Grant Number: F5B30323
Title: Strontium Isotopic Tracing Of Coal Bed Natural Gas Product Water To Determine Potential Beneficial Uses And Recharge Into Shallow Groundwater Systems.
Investigators: Brinck, Elizabeth
Institution: University of Wyoming
EPA Project Officer: Lee, Sonja
Project Period: June 1, 2003 through May 1, 2008
Project Amount: $91,981
RFA: STAR Graduate Fellowships (2005) RFA Text | Recipients Lists
Research Category: Academic Fellowships
Coal bed natural gas (CBNG) production is the process of extracting natural gas, almost entirely composed of methane, from coal seams by depressurizing the coal through the removal of the coal aquifer water. To extract gas from the coal seam, water is pumped to the surface through a central pipe while the methane is collected in an annular pipe. In Wyoming’s Powder River Basin, most of this water is discharged directly to surface drainages; however land surface owners in this arid area are eager to put this water to beneficial use. Due to the sodium-bicarbonate composition of the CBNG water, direct use of this water for irrigation and crop production often results in excess sodium in the soil. Methods being employed to protect soil quality under CBNG irrigation include the application of gypsum and sulfur to the land surface.
This research will utilize naturally occurring strontium isotopes to trace the infiltration of the CBNG water into near-surface aquifers, as well as monitor the introduction of gypsum and sulfur to these near-surface aquifers in areas undergoing CBNG irrigation. Additionally, sulfur addition has the potential to disrupt the calcium cycle in soil and plants. Strontium is an effective tracer of the calcium cycle and will be employed in this research to monitor changes in soil and plant calcium due to sulfur application in CBNG irrigation projects.
I will determine the effectiveness of using stable strontium isotopes as an aqueous, environmental tracer for the purpose of identifying recharge to groundwater, impacts on groundwater, and effects upon the calcium cycle.
This research will address the goals outlined above by studying the interaction of CBNG produced water with the local near-surface aquifers through characterization of the aquifers’ unique 87Sr/ 86Sr ratios and strontium concentrations. Additionally, this study will monitor potential contamination of groundwater and alteration of the soil-plant calcium cycle in areas undergoing irrigation with CBNG water by characterizing the 87Sr/ 86Sr ratios of the soil applications and identifying changes in the strontium ratio of the groundwater and soil water. Any changes in the source of plant calcium will also be identifiable through this method. The additional measurements of soil calcium concentration will fully characterize the local calcium cycle and any alterations.
The results from these studies should pave the way for this innovative tracer to be used in many situations where groundwater quality is at risk. My research is designed to test the flexibility of the strontium tracer by testing its applicability in a variety of dissimilar situations. Successful application of this tracer in my proposed study could open up future research aimed at groundwater protection through the tracing of contamination sources.