Phantom PHCs? Using the F2:F3b ratio to eliminate false PHC detections in clean soils. Francine Kelly-Hooper, Soils Scientist CH2M HILL Canada

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1 Phantom PHCs? Using the F2: ratio to eliminate false PHC detections in clean soils Francine Kelly-Hooper, Soils Scientist CH2M HILL Canada

2 Research Partners Alberta Parks and Protected Areas Division ALS Laboratory Group Canadian Association of Petroleum Producers, Petroleum Technology Alliance of Canada Environment Canada Oil Spills Research Centre Geological Survey of Canada Husky Energy Imperial Oil Natural Sciences and Engineering Research Council Natural Resources Canada Orphan Well Association

3 2007: Crude Oil Spiked Peat Experiment Spiked peat with crude oil to study biogenic vs petrogenic carbon patterns over a 300 day period.

4 2008: Diesel Spiked Manure Experiment Spiked composted manure and sand with diesel oil and studied biogenic vs petrogenic carbon patterns over a 300 day period.

5 2009: Background PHC survey of 34 sites located in Alberta, BC and Newfoundland Canadian Geologic Survey collected soils samples and shipped them to ALS Laboratories in Waterloo for PHC, PAH and grain size analysis.

6 What are biogenic organic compounds? BOCs are carbon-based compounds that are naturally biosynthesized by living organisms. BOCs are ubiquitous throughout the environment. BOC groups containing C, H and O include: lipids, carbohydrates, proteins and nucleic acids. BOC hydrocarbon groups containing only C and H include n-alkanes.

7 Why are BOCs confused as PHCs?

8 Canadian Council of Ministers of the Environment (CCME) Reference Method for the Canada-Wide Standard (CWS) for Petroleum Hydrocarbons (PHC) in Soil Methods can produce false positives in uncontaminated organic materials (e.g. peat, manure, etc.).

9 The problem is that the hexane and acetone solvents indiscriminately extract all carbon from petroleum and biological sources. The goal is to catch petroleum hydrocarbons. However, background biogenic organic compounds are inadvertently caught as well. Source: thedatingangle.com

10 GC-FID Analysis of Sample Extract carrier gas line Extract injection Vaporizer Oven flame Flame Ionization Detector ion flow ) ) ) ) ) ) ) ) detector electronic signal F2, F3, F4 concentrations quantified by chromatogram integrations capillary column

11 Diesel-Spiked Peat GC-FID Chromatogram F2 C10-C16 F3 C16-C34 F4 >C34 pa Diesel F mg/kg Reported F mg/kg Peat F mg/kg UCM Retention Time (minutes)

12 Classification of Petroleum Hydrocarbon Sources by Carbon Number Range CCME Fractions F1 to F4 F1 F2 F4 C6-C10 C10-C16 C16-C34 > C34 F3 Gasoline Biogenic Organic Compounds (e.g. fatty acids, sterols, waxes, etc. ) Diesel/No. 2 Fuel Oil No. 6 Oil/Lube Oil/Heavy fuels, Tar, Asphalts Crude Oil C6 C10 C16 C34 >C34 Carbon Numbers

13 Classification of Petroleum Hydrocarbon Sources by Carbon Number Range LEPH and HEPH Ranges LEPH F2 C10-C19 HEPH C19-C32 Biogenic Organic Compounds (e.g. fatty acids, sterols, waxes, etc. ) Gasoline Diesel/No. 2 Fuel Oil No. 6 Oil/Lube Oil/Heavy fuels, Tar, Asphalts Crude Oil C6 C10 C19 C32 Carbon Numbers

14 Comparison of Background Soil Survey Results to Alberta Tier 1 Soil and Groundwater Remediation Guidelines

15 Alberta Tier 1 Soil and Groundwater Remediation Guidelines March 18, 2014 Coarse textured soil and groundwater remediation guidelines may be used for organic contaminants in organic soils

16 34 Background Soil Samples: AB, BC, NL Comparisons of F2, F3, F4 Concentrations to AB Tier 1 Soil Remediation Guidelines Surface Soils Natural/Agr/Resid/Parkland Guidelines F2 (mg/kg) mg/kg 0 samples exceeded F2 course soil standards Only F3 exceeded the Guidelines 1600 F3 (mg/kg) mg/kg 16 samples (47%) exceeded F3 coarse soil standard 0 F4 (mg/kg) mg/kg 0 samples exceeded F4 course soil standards 0 0% 10% 20% 30% 40% %TOC

17 All soils with >28% TOC exceeded the F3 coarse soil standards Peat soils have >40% TOC

18 Peat soils cover 11% of Canada 0-1% 2-8% 6-25% 26-75% % source: Peatland Resources of Canada

19 Peat soils cover 18% of Alberta source: Alberta Geological Survey

20 But there is a light at the end of the tunnel!

21 F2: presence vs absence ratio Ratio >0.10 = PHC presence (contaminated) Ratio <0.10 = PHC absence (clean)

22 (C16-C22) and (C22-C34) Distributions in Diesel and Clean Peat F2 Total F3 F4 Clean Peat Nil F2 (C16-C22) (C22-C34) 7% 93% Diesel Contaminated Peat High F2 37% 63% High F2 11% 89% Diesel C10 C16 C22 C34 Carbon Number

23 (C16-C22) and (C22-C34) Distributions in Crude Oil and Clean Peat F2 Total F3 F4 Nil F2 (C16-C22) (C22-C34) 7% 93% Peat Crude + Peat High F2 31% 69% High F2 50% 50% Federated Crude Oil C10 C16 C22 C34 Carbon Number

24 13 Fresh Crude Oil Samples 34 Background Soil Samples Median Median 49% 51% 7% 93% % of Total F3 Concentration Crude Oil Samples % of Total F3 Concentration Soil Samples (C16-C22) (C23-C34) (C16-C22) (C23-C34)

25 Heavy PHC sources such as engine oil and tar have high percentages as do clean soils, manure and biosolids Diesel Fuel High 89% 11% Crude Oil High 47% 53% Engine Oil Low 6% 94% Tar Low 14% 86% Peat 7% Low 93% F2 F3 F4

26 F2: Ratio Diesel PHC Presence Value is >0.10 F2 F2: Ratio Clean Peat F2 = 10 mg/kg = 1,395 mg/kg = 0.01 ABSENT Diesel Spiked Peat F2 = 613 mg/kg = 2,816 mg/kg = 0.79 PRESENT Diesel F2 = 823 mg/kg = 371 mg/kg C10 C16 C22 C34 Carbon Number = 2.22 PRESENT

27 F2 F2: Ratio Crude Oil PHC Presence Value is >0.10 F2: Ratio Clean Peat F2 = 10 mg/kg = 1,000 mg/kg = 0.01 ABSENT Crude Oil Spiked Peat F2 = 1,000 mg/kg = 2,000 mg/kg = 0.50 PRESENT F2 = 1,000 mg/kg = 1,200 mg/kg = 0.83 PRESENT Crude Oil C10 C16 C22 C34 Carbon Number Total F3

28 0.10 PHC absence PHC presence Measured F3 (mg/kg) (log scale) F2: Ratios and F3 Concentrations Clean Manure Compost and Background Soil Survey Samples Manure Compost, Peat and Sand Spiked with Diesel and Crude OIl Day 0 & Day 300 Samples Contaminated samples >300 mg/kg F3 also had >0.10 F2: ratio F2: Ratio 300 mg/kg F3 coarse soil guideline clean soils/compost contaminated soil/compost contaminated sand

29 Biogenic vs Petrogenic Decision Tree Does the contamination source have an F2: ratio of >0.10? Pre-screening requires chromatogram interpretation expertise Tier 1 Evaluation Pre-screening Yes No Do not proceed with evaluation Does the GC-FID pattern in the peat sample match the GC-FID pattern(s) in the contamination source and/or background soil? Yes Do the F2 and/or F4 concentrations in the soil sample exceed soil standards? No Does the F3 concentration in the soil sample exceed the soil standard? No Exclude sample from evaluation Yes Management required No Management not required Yes Is the F2: ratio in the soil sample >0.10? Tier 2 Evaluation No Management not required Yes Does the soil sample biomarker and/or PAH analysis indicate PHC presence? No Management not required Yes Management required

30 Rules of Thumb for Practical Applications Cannot be used to assess soils contaminated by heavy PHC products (e.g. motor oil, tar, asphalt, etc.) PHC contamination source must have an F2: ratio of greater than or equal to 0.10 Chromatograms must be studied for every soil sample to ensure that all contaminated samples have the same PHC source. Clean samples are identified by non-detectable F2 concentrations combined with the absence of PHC UCMs.

31 Francine Kelly-Hooper