Soil Conductivity, Gas Flux, and Carbon Isotope Analysis: The Next - PowerPoint PPT Presentation

Soil Conductivity, Gas Flux, and Carbon Isotope Analysis: The Next Step In Locating Hydrocarbon Subsurface Plumes? Lisa Moehlman, Kathlyne Hyde, Richard Nhan, Steven D. Presenting Members Siciliano, Kris Bradshaw, Morgan Sather, and Trevor Carlson Integrity  Excellence  Responsibility

Pre-screening Limited amount and technology for pre-screening Pre-screening can help to: • Improve the quality of site assessment • Locate unknown hot spots • Save time and money

Objective Determine if the combination of • Carbon flux • Carbon isotopes • EM maps can be used as a screening tool

Background CO 2 Flux Electrical magnitude maps +CH 4 +CH 4 Sihota, N.J., K.U Mayer. 2012. Characterizing vadose zone hydrocarbon biodegradation using carbon dioxide effluxes, isotopes and reactive transport modeling. Vadose Zone Journal. Soil Science Society of America. 2.41.

Background δ C 13 Isotope • Microbes prefer C 12 isotope • PHC are high in C 12 -signatures • Increased C 13 -signatures and decreased C 12 -signatures • δ C 13 CO 2 levels: -18 to -24 indicate PHC degradation

Locations Raymore Saskatoon Davidson

Decision units

Methods 1. Soil temperature and moisture 2. Carbon flux readings 3. Gas samples for Isotope analysis 4. EM readings 5. Phase II Assessment

Raymore carbon flux results Circles are CO 2 fluxes Slightly above background (<10 µmol m -2 s -1 ) (no colours indicate at background) Above background (>10 µmol m -2 s -1 ) Well above background (>50 µmol m -2 s -1 ) 7 DU3 DU2 2 4 8 5 1 9a 3 6 9 12 10 11 DU4

Carbon flux and isotope results Elevated CO 2 Respiration Clean Possible Raymore 0 11th W Davidson -5  C   CO 2 ( ‰) -10 -15 Hydrocarbon Degradation Confirmed -20 -25 1 10 100 1000 10000 log+1 CO 2 (umol m -2 s -1 ) Fig. δ C 13 of carbon dioxide vs background corrected carbon dioxide flux at Raymore, 11 th &W, and Davidson bulk transfer stations

Electrical magnitude

Check list PHC Remediation CO 2 Flux (µmol m -2 s -1 ) δ C 13 CO 2 (‰) Low EM reading Occurring? Yes Possibly No

Lab analysis

Raymore carbon flux vs. lab results Slightly above background (<10 µmol m -2 s -1 ) Circles are CO 2 fluxes C6-C10 detectable Squares are C6-C10 Above background (>10 µmol m -2 s -1 ) (no colours indicate at background ) C6-C10 > 400 ppm Well above background (>50 µmol m -2 s -1 ) C6-C10 >1000ppm DU3 7 DU2 2 4 8 5 1 9a 3 6 9 12 10 11 DU4

Conclusions Considerations • Heavy clay • Weather permitting • Compacted sites • Contamination depth Industry implications

Acknowledgements Supervisor: Steven Siciliano The Environmental Soil Toxicology Lab group and undergrads Sustainable In-situ Remediation Co-operative Alliance Federated Co-operatives limited

Questions? www.usask.ca

Raymore EM maps 0.5 m (top left), 1 m (top right), and 3 m (bottom center)

Davidson carbon flux vs. lab results Slightly above background (<40 µ mol m ‐ 2 s ‐ 1 ) Circles are CO 2 fluxes C6 ‐ C10 detectable Squares are C6 ‐ C10 Above background (>40 µmol m ‐ 2 s ‐ 1 ) (no colours indicate at background) C6 ‐ C10 > 400 ppm Well above background (>100 µmol m ‐ 2 s ‐ 1 ) C6 ‐ C10 >1000ppm

Davidson EM maps 0.5 m (left) & 1 m (right)

Davidson EM Maps 3 m (left) & 5 m (right)

11 th &W carbon flux vs. lab results Circles are CO 2 fluxes 1 Squares are C6-C10 (no colours indicate at background) 9 2 Slightly above background (<40 µmol m -2 s -1 ) C6-C10 detectable 3 Above background (>40 µmol m -2 s -1 ) 4 7 10 C6-C10 > 400 ppm Well above background (>100 µmol m -2 s -1 ) 5 C6-C10 >1000ppm 8 11 12 6

11 th & W EM maps 0.5 m (left) & 1 m (right)

11 th & W EM maps 3 m (left) & 5 m (right)