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Use of GCxGC-TOFMS in litigious mixed condensate plumes: Environmental forensics case study - Multidimensional Chromatography Workshop

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Authors: Court D. Sandau and Lisa N. Kates
Chemistry Matters Inc.

Abstract; Condensate is a complex mixture of light petroleum hydrocarbons that is primarily used to dilute heavy crude oil for transport through pipelines. Many heavy oils, especially bitumen from the oil sands in northern Alberta, use condensate to dilute the bitumen to allow the product to flow to refineries where the oil can be upgraded. This is where the term ‘Dilbit’ was derived. Condensate is valuable; it can be recycled and reused and is frequently transported through the North American pipeline network. Pipelines gather at pipeline terminals where there can be multiple sources and multiple suppliers of different types of condensates. When leaks occur at these terminals, it can be difficult to determine the exact source of the leak, especially if pipeline integrity seems intact. GCxGC-TOFMS is the ideal technique to examine mixed condensate plumes as it allows the comprehensive fingerprint of the condensate to be determined and simultaneously provides substantial data to evaluate weathering and plume movement. In addition, the amount of chemicals measured using GCxGC-TOFMS can allow source apportionment of multiple sources so that allocation of the cleanup responsibility can be made. This presentation will discuss the use of GCxGC-TOFMS in legal case studies involving mixed condensate plumes. Real scenarios of condensate plumes will be presented showing how GCxGC-TOFMS data clarified the results compared to conventional analysis. This presentation will also cover the hurdles of using a novel and unconventional technique for litigation proceedings.

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Use of GCxGC-TOFMS in litigious mixed condensate plumes: Environmental forensics case study - Multidimensional Chromatography Workshop

  1. 1. Use of GCxGC-TOFMS in litigious mixed condensate plumes: Environmental forensics case study Court D. Sandau and Lisa N. Kates Presented at Multidimensional Chromatography Workshop January 5, 2020 – Honolulu, Hawaii © 2020 Chemistry Matters Inc. Making environmental data meaningful Toluene C8 C9 C10 C11C12 C14 C16 C18 C20
  2. 2. © 2020 Chemistry Matters Inc. GCxGC in Litigation Proceedings • Daubert Standard for Admissibility – benchmark in US, applied in Canada and UK – Demonstrate that technique has been peer reviewed, published, or accepted • Ontario Ministry of Environment – three official methods GCxGC for POPs in environment Chemistry Matters Forensics Work with GCxGC • Used GCxGC-TOFMS for over 150 arson investigations since 2016 – Data accepted in 1 trial, thus far • On going litigation cases: Oil spill weathering assessment, historical gasoline spill (dissolved phase), mixed condensate plumes 2MDCW 2020 - Hawaii
  3. 3. © 2020 Chemistry Matters Inc. What is Condensate? • Complex mixture of light petroleum hydrocarbons (600-800 compounds) • Primarily used to dilute heavy crude oil for transport through pipelines • Heavy oils, especially bitumen from the oil sands in northern Alberta, use condensate to dilute the bitumen (‘Dilbit’) • Condensate is valuable; recycled and reused and is frequently transported through the North American pipeline networks 3MDCW 2020 - Hawaii Toluene C8 C9 C10 C11 C12 C14 C16 C18 C20 Gasoline Diesel Motor Oil Condensate Crude Oil Number of Carbon Atoms 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52
  4. 4. © 2020 Chemistry Matters Inc. What is the issue? 4MDCW 2020 - Hawaii • Labyrinth of pipelines, from multiple suppliers in same area makes daylighting all pipes difficult (slow and expensive) • Most recent leak blamed and assumed as source (but it has been repaired) • All lines in area have been ‘pigged’ or pressure tested – No leaks identified • Product continues to accumulate in groundwater monitoring wells (up to 80cm) What is the source of the condensate? Who should pay for cleanup?
  5. 5. © 2020 Chemistry Matters Inc. 5MDCW 2020 - Hawaii Investigation Area Below Ground Pipelines Groundwater Flow Sample of Interest (different)
  6. 6. © 2020 Chemistry Matters Inc. Conventional GC-FID PHC Analysis of Condensates 6 14-15 14-16 15-17 15-20 CON stream MDCW 2020 - Hawaii Total Petroleum Hydrocarbon (TPH) analysis provides little visual distinctions or data
  7. 7. © 2020 Chemistry Matters Inc. GCxGC Chromatograms 7 MDCW 2020 - Hawaii 14-15 14-16 Whole chromatogram C8 to C44
  8. 8. © 2020 Chemistry Matters Inc. GCxGC-FID Results: Sample 14-16 8 0 1 2 3 4 5 6 7 8 0 20 40 60 80 100 120 SecondDimensionRetentionTime(min) First Dimension Retention Time (min) 18C366760 7702 - 14-16 Pr 610 peaks detected MDCW 2020 - Hawaii
  9. 9. © 2020 Chemistry Matters Inc. GCxGC-FID Results: Sample 15-17 9 620 peaks detected 0 1 2 3 4 5 6 7 8 0 20 40 60 80 100 120 SecondDimensionRetentionTime(min) First Dimension Retention Time (min) 18C366760 7703 - 15-17 Pr MDCW 2020 - Hawaii
  10. 10. © 2020 Chemistry Matters Inc. GCxGC Chromatograms 10 MDCW 2020 - Hawaii Steranes, hopanes, triaromatic steranes 14-16 14-15
  11. 11. © 2020 Chemistry Matters Inc. GCxGC Chromatograms 11 MDCW 2020 - Hawaii C3 to C7 alkylbenzenes 14-16 14-15
  12. 12. © 2020 Chemistry Matters Inc. Software Limitations • Software is not yet capable of consistently exporting aligned non-targeted peak lists • Time consuming aligning peaks and data munging to get to data analysis – Limits use for forensics cases that could use non-targeted analysis 12 MDCW 2020 - Hawaii Developed stencils to capture groups of compounds and selected target compounds Alkylbenzenes Alkanes Dicyclonaphthenes Fluorenes Hopanes Indanes Naphthalenes Phenanthrenes Streranes TriAromatic Steranes Tricyclic Terpanes Cyclonaphthenes
  13. 13. © 2020 Chemistry Matters Inc. Investigation Site Data and Data Wrangling • 10 product samples from wells (collected over 2 years) – free product needed to be present in the well for sampling • 4 on-site source samples • 6 library condensate samples (for comparison) • 200 targeted stencil areas • Areas must be detected in 50% of samples • Created mixture of condensates, injected in triplicate • Triplicate must be < 25% RSD (reproducible stencils) • 101 stencil areas remained for statistical analysis, imputed missing values • Target compounds for weathering ratios were exported separately • PCA/HCA completed on % total normalized data 13 MDCW 2020 - Hawaii
  14. 14. © 2020 Chemistry Matters Inc. Sampling Locations 14MDCW 2020 - Hawaii Groundwater Flow
  15. 15. © 2020 Chemistry Matters Inc. Evaporation Ratio 15MDCW 2020 - Hawaii C5:C7 1.83 1.62 1.33 1.06 0.44 Groundwater Flow
  16. 16. © 2020 Chemistry Matters Inc. Weathering Ratio 16MDCW 2020 - Hawaii 0.82 0.60 0.65 0.45 0.22 BT:EX Groundwater Flow
  17. 17. © 2020 Chemistry Matters Inc. Water Solubility Ratio 17MDCW 2020 - Hawaii 0.43 0.85 0.84 0.74 0.99 TOL:MCH Groundwater Flow
  18. 18. © 2020 Chemistry Matters Inc. Histogram Charts of GCxGC Results 18MDCW 2020 - Hawaii Groundwater Flow
  19. 19. © 2020 Chemistry Matters Inc. Multivariate Statistical Analysis of GCxGC Results 19 • 75% of variance explained in first two PCs • 14-15 (SW corner) is different from all other wells from investigation MDCW 2020 - Hawaii Library Samples Source Samples from Site Product Samples from Site Different Samples from Site
  20. 20. © 2020 Chemistry Matters Inc. 20 Reducing dimensionality using PCA and using all three PCs, 14-15 has only a 1 in 10,000 chance of being condensate from the same source as other wells. MDCW 2020 - Hawaii How Different is 14-15 from other wells?
  21. 21. © 2020 Chemistry Matters Inc. Conclusions • Free product in 14-15 is conclusively a different free product from a different release • Using multiple lines of evidence, statistics and visual aids helps communicate complex results for litigation proceedings 21 MDCW 2020 - Hawaii 14-15 14-16
  22. 22. © 2020 Chemistry Matters Inc. Future Development • Full untargeted analysis with peak alignment (use all 600-800 peaks) • Full automated weathering analysis (use all known weathering ratios) • Streamline work flow • Develop a library of condensates for reference and application for analysis • Examination of biomarkers specific to condensate for additional lines of evidence of potential sources • Forensic experimental setup and advice – library / source sample requirements (anchors for PCA/HCA) – minimum sample requirements – variability assessment (error analysis with replicates) – pooled sample of all samples to develop targeted / “non-targeted” list of compounds 22 MDCW 2020 - Hawaii
  23. 23. © 2020 Chemistry Matters Inc. 23 MDCW 2020 - Hawaii Thank you for your attention Contact Info: Chemistry Matters Inc. Court Sandau Cell: +1.403.669.8566 Email: csandau@chemistry-matters.com www.chemistry-matters.com Visit my website and sign up for email for automatic receipt of my blogs.

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