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1 Making environmental data meaningful Interpretation of sediment PAH data after an oil spill into a fresh water environment Court Sandau, PhD Watertech 2017 April 3-5,

2 Why are PAHs monitored after an oil spill? 2

3 Oil Chemistry o Complex mixture o 10,000s of chemicals o Grouped into specific chemical types Middle Eastern Crude Oil 3

4 Oil Chemistry Alkanes Branched alkanes Cyclic alkanes Benzene Alkylbenzenes PAHs Alkyl PAHs Biomarkers 4

5 Weathering The influence of physical, chemical and biological forces on the physical and chemical composition of contaminants in the environment Volatilization Solubilization Biodegradation biotransformation 5

6 Volatility For free phase product, related to the vapour pressure High vapour pressure = more volatile 10.4 Pa benzene 12,700 Pa pentane hexane 57,900 Pa 20,200 Pa naphthalene Pa 3800 Pa 1880 Pa phenanthrene toluene octane Pa Most volatile compounds are gone within weeks of spill pyrene 6

7 Solubilization Moving from oil phase (lipophilic) to water phase (hydrophilic) Driven by: Solubility K ow (octanol:water partitioning) 7

8 Solubility Amount of compound that will dissolve in pure water For compounds with C and H, basically related to size of molecule Larger = less soluble 31 mg/l benzene toluene 1790 mg/l 470 mg/l pentane hexane octane 38 mg/l 9.5 mg/l 0.66 mg/l Big molecules don t dissolve in water. Solubility in competition with K ow. naphthalene phenanthrene pyrene 1.1 mg/l 0.13 mg/l 8

9 Octanol:Water Partitioning Model for lipid partitioning Also works for organic carbon K ow = C octanol / C water Log scale Unitless benzene toluene pentane hexane octane Big molecules stay in free phase or bind to organic matter (i.e. sediment) naphthalene phenanthrene pyrene

10 Organic carbon drives sediment concentrations Once equilibrium is reached, organic carbon drives PAH concentrations in sediments Equilibrium is reached quite quickly 10

11 Oil Compounds Susceptibility to Biodegradation Most susceptible C 5 -C 6 Hydrocarbons Olefins n-alkanes Monoaromatics Isoalkanes Parent PAH > 2 ring C 1 -alkyl PAH C 2 -alkyl PAH C 3 -alkyl PAH C 4 -alkyl PAH Triterpanes Steranes Diasteranes Aromatic Steranes Porphyrins Less susceptible 11

12 Why are PAHs the focus post spill? Not very volatile Not soluble in water/bind to organic carbon in sediment Resist biodegradation Potential to bioaccumulate (very minimal) Known toxicity (mediated through Ah receptor) Constitutes low percentage(<1-10%) quantities of crude oil High enough concentrations to see in environment 12

13 But BEWARE! 13

14 Athabasca River (upstream) 12% Athabasca River Upstream Sediment 10% 8% 6% 4% 2% 0% NAP C1 NAP C2 NAP C3 NAP C4 NAP FLU C1 FLU C2 FLU C3 FLU PHE/ANT C1 PHE/ANT C2 PHE/ANT C3 PHE/ANT C4 PHE/ANT DBT C1 DBT C2 DBT C3 DBT C4 DBT FLRN/PYR C1 FLRN/PYR C2 FLRN/PYR C3 FLRN/PYR C4 FLRN/PYR BaA/CHR C1 BaA/CHR C2 BaA/CHR C3 BaA/CHR C4 BaA/CHR 14

15 Mackenzie River (Pristine Area) 25% Mackenzie River Alkyl PAH Homologous Series 20% 15% 10% 5% 0% NAP C1 NAP C2 NAP C3 NAP C4 NAP FLU C1 FLU C2 FLU C3 FLU PHE/ANT C1 PHE/ANT C2 PHE/ANT C3 PHE/ANT C4 PHE/ANT DBT C1 DBT C2 DBT C3 DBT C4 DBT FLRN/PYR C1 FLRN/PYR C2 FLRN/PYR C3 FLRN/PYR C4 FLRN/PYR BaA/CHR C1 BaA/CHR C2 BaA/CHR C3 BaA/CHR C4 BaA/CHR 15

16 North Saskatchewan River 12% 16-SW1AD % 8% 6% 4% 2% 0% NAP C1 NAP C2 NAP C3 NAP C4 NAP FLU C1 FLU C2 FLU C3 FLU PHE/ANT C1 PHE/ANT C2 PHE/ANT C3 PHE/ANT C4 PHE/ANT DBT C1 DBT C2 DBT C3 DBT C4 DBT FLRN/PYR C1 FLRN/PYR C2 FLRN/PYR C3 FLRN/PYR C4 FLRN/PYR BaA/CHR C1 BaA/CHR C2 BaA/CHR C3 BaA/CHR C4 BaA/CHR 16

17 Red Deer River (upstream of Sundre) 0.4 CTRL S/C Naphthalene C1 naphthalene C2 naphthalene C3 naphthalene C4 naphthalene Fluorene C1 flur ene C2 flur ene C3 flur ene Phenanthrene/Anthracene C1 phenanthrene/anthracene C2 phenanthrene/anth. C3 phenanthrene/anth. C4 phenanthrene/anth. Dibenzothiophene C1 dibenzothiophene C2 dibenzothiophene C3 dibenzothiophene C4 dibenzothiophene Fluoranthene/Pyrene C1 fluoranthene/pyrene C2 fluoranthene/pyrene C3 fluoranthene/pyrene C4 fluoranthene/pyrene Benz(a)anthracene/Chrysene C1 B(a)A/chrysene C2 B(a)A/chrysene C3 B(a)A/chrysene C4 B(a)A/chrysene 17

18 PAHs in rivers Rivers are catchment areas, sinks for sediments, especially reservoirs PAHs have long half-lives PAHs are ubiquitous All rivers in Alberta have PAHs In sediment In organic rich phases Most are petrogenic origin Above Tier 1 guidelines 18

19 Keys to Successful PAH Forensics Interpretation Sufficiently low detection limits (need a pattern or measured concentration) Parent PAHs: 0.01 to mg/kg Alkyl-PAHs: 0.04 to mg/kg Characterize background (upstream locations) PAHs will likely be above guidelines upstream of release Analyze the product that was released (source characterization) Sample fine sediment, low energy areas, highest organic carbon Sampling coarse grains and having lots of NDs does not help the investigation 19

20 0.18 Detection Limits Matter Comparison of sample fingerprints for same sample First Analysis 22 NDs Re-Analysis 2 NDs 20

21 Environmental Forensics Fingerprint Diagnostic Ratios Statistical Analysis Source Apportionment Visual comparison of PAH data Relative concentration of key PAHs Comprehensive analysis of all PAH data Determine amount of contaminants from each known source (not covered in this talk)

22 Case Study 22

23 Background Sediment sampling results over 2 years post release Impacts of release mostly in side channels Could oil impacted sediments be identified using environmental forensics techniques? Analyzed for extended PAHs, included parent PAHs and alkylated PAHs 23

24 Braided River Channels Freshet flow scouring action Changing course of channels Changes to types of environment Where are the accumulation areas? They can change post large freshet. Year 1 Year 2 24

25 Braided rivers change course Year 1 Year 2 25

26 Sediment Study Sediment concentrations of PAHs were compared with CCME Interim Sediment Quality Guideline Freshwater Aquatic Life (FAL) Many samples (including upstream) for naphthalene, 2-methylnaphthalene and phenanthrene were above guideline. 26

27 River U/S POE River D/S POE Sediment Study Naphthalene Downstream Reservoir Concentra on (mg/kg dry weight) Guideline 0 CTRL S/C LTM3 LTM6 Site 2 Site 3 LTM11C LTM13 LTM14 WBASIN1 WBASIN2 WBASIN3 WBASIN4 WBASIN5 LTM16(1) LTM16(2) LTM16(3) LTM16(4) LTM16(5) LTM17 LTM18 LTM19 LTM20 LTM21 LTM River samples Side channel samples Downstream Reservoir 27

28 River U/S POE River D/S POE Sediment Study 2-Methyl-naphthalene Downstream Reservoir Concentra on (mg/kg dry weight) Guideline 0 CTRL S/C LTM3 LTM6 Site 2 Site 3 LTM11C LTM13 LTM14 WBASIN1 WBASIN2 WBASIN3 WBASIN4 WBASIN5 LTM16(1) LTM16(2) LTM16(3) LTM16(4) LTM16(5) LTM17 LTM18 LTM19 LTM20 LTM21 LTM River samples Side channel samples Downstream Reservoir 28

29 River U/S POE River D/S POE Sediment Study Phenanthrene Downstream Reservoir Concentra on (mg/kg dry weight) Guideline 0 CTRL S/C LTM3 LTM6 Site 2 Site 3 LTM11C LTM13 LTM14 WBASIN1 WBASIN2 WBASIN3 WBASIN4 WBASIN5 LTM16(1) LTM16(2) LTM16(3) LTM16(4) LTM16(5) LTM17 LTM18 LTM19 LTM20 LTM21 LTM River samples Side channel samples Downstream Reservoir 29

30 PAH Fingerprints Visual comparisons PAH groups Types of oils and refined products. light crude, heavy crude, gasoline, diesel Nature of background sources of PAHs

31 Oil Types Plains Product 16% 14% 12% 10% 8% 6% 4% Light Crude Light PAHs dominant Nice bell-shaped patterns (Product sample for case study) 2% 0% Naphthalene C1 naphthalene C2 naphthalene C3 naphthalene C4 naphthalene Acenaphthene C1 acenaphthene Biphenyl C1 biphenyl C2 biphenyl Fluorene C1 flur ene C2 flur ene C3 flur ene Phenanthrene/Anthracene C1 phenanthrene/anthracene C2 phenanthrene/anth. C3 phenanthrene/anth. C4 phenanthrene/anth. Dibenzothiophene C1 dibenzothiophene C2 dibenzothiophene C3 dibenzothiophene C4 dibenzothiophene Fluoranthene/Pyrene C1 fluoranthene/pyrene C2 fluoranthene/pyrene C3 fluoranthene/pyrene C4 fluoranthene/pyrene Benz(a)anthracene/Chrysene C1 B(a)A/chrysene C2 B(a)A/chrysene C3 B(a)A/chrysene C4 B(a)A/chrysene Benzofluoranthene/Benzopyrene C1 benzofluoranthene/benzopyrene C2 benzofluoranthene/benzopyrene 18% 16% K1A-Source 14% 12% Bitumen Heavy PAHs dominant Mixed patterns 10% 8% 6% 4% 2% 0% NAP C1 NAP C2 NAP C3 NAP C4 NAP ACE C1 ACE BPH C1 BPH C2 BPH FLU C1 FLU C2 FLU C3 FLU PHE/ANT C1 PHE/ANT C2 PHE/ANT C3 PHE/ANT C4 PHE/ANT DBT C1 DBT C2 DBT C3 DBT C4 DBT FLRN/PYR C1 FLRN/PYR C2 FLRN/PYR C3 FLRN/PYR C4 FLRN/PYR B(a)A/CHR C1 B(a)A/CHR C2 B(a)A/CHR C3 B(a)A/CHR C4 B(a)A/CHR BFLRN/BPYR C1 BFLRN/BPYR C2 BFLRN/BPYR 31

32 60% 50% Gasoline Product Types 30% 25% Diesel Fuel - 0% Diesel 40% 20% 30% 15% 20% 10% 10% 0% NAP C1 NAP C2 NAP C3 NAP C4 NAP ACE C1 ACE BPH C1 BPH C2 BPH FLU C1 FLU C2 FLU C3 FLU PHE/ANT C1 PHE/ANT C2 PHE/ANT C3 PHE/ANT C4 PHE/ANT DBT C1 DBT C2 DBT C3 DBT C4 DBT 14% FLRN/PYR C1 FLRN/PYR C2 FLRN/PYR C3 FLRN/PYR C4 FLRN/PYR B(a)A/CHR C1 B(a)A/CHR C2 B(a)A/CHR C3 B(a)A/CHR C4 B(a)A/CHR BFLRN/BPYR C1 BFLRN/BPYR C2 BFLRN/BPYR 5% 0% NAP C1 NAP C2 NAP No. 5 Oil - 0% Fuel Oil C3 NAP C4 NAP ACE C1 ACE BPH C1 BPH C2 BPH FLU C1 FLU C2 FLU C3 FLU PHE/ANT C1 PHE/ANT C2 PHE/ANT C3 PHE/ANT C4 PHE/ANT DBT C1 DBT C2 DBT C3 DBT C4 DBT FLRN/PYR C1 FLRN/PYR C2 FLRN/PYR C3 FLRN/PYR C4 FLRN/PYR B(a)A/CHR C1 B(a)A/CHR C2 B(a)A/CHR C3 B(a)A/CHR C4 B(a)A/CHR BFLRN/BPYR C1 BFLRN/BPYR C2 BFLRN/BPYR 12% 10% 8% 6% 4% 2% 0% NAP C1 NAP C2 NAP C3 NAP C4 NAP ACE C1 ACE BPH C1 BPH C2 BPH FLU C1 FLU C2 FLU C3 FLU PHE/ANT C1 PHE/ANT C2 PHE/ANT C3 PHE/ANT C4 PHE/ANT DBT C1 DBT C2 DBT C3 DBT C4 DBT FLRN/PYR C1 FLRN/PYR C2 FLRN/PYR C3 FLRN/PYR C4 FLRN/PYR B(a)A/CHR C1 B(a)A/CHR C2 B(a)A/CHR C3 B(a)A/CHR C4 B(a)A/CHR BFLRN/BPYR C1 BFLRN/BPYR C2 BFLRN/BPYR 32

33 Petrogenic / Pyrogenic No. 5 Fuel Oil - 0% 14% 12% 10% 8% 6% Petrogenic Bell-shaped family groups Oil products 4% 2% 0% NAP C1 NAP C2 NAP C3 NAP C4 NAP ACE C1 ACE BPH C1 BPH C2 BPH FLU C1 FLU C2 FLU C3 FLU PHE/ANT C1 PHE/ANT C2 PHE/ANT C3 PHE/ANT C4 PHE/ANT DBT C1 DBT C2 DBT C3 DBT C4 DBT FLRN/PYR C1 FLRN/PYR C2 FLRN/PYR C3 FLRN/PYR C4 FLRN/PYR B(a)A/CHR C1 B(a)A/CHR C2 B(a)A/CHR C3 B(a)A/CHR C4 B(a)A/CHR BFLRN/BPYR C1 BFLRN/BPYR C2 BFLRN/BPYR 35% EPRI Study PAHs - Petroleum Tar 30% 25% Pyrogenic Scree-shaped family groups Combustion products 20% 15% 10% 5% 0% NAP C1 NAP C2 NAP C3 NAP C4 NAP ACE C1 ACE BPH C1 BPH C2 BPH FLU C1 FLU C2 FLU C3 FLU PHE/ANT C1 PHE/ANT C2 PHE/ANT C3 PHE/ANT C4 PHE/ANT DBT C1 DBT C2 DBT C3 DBT C4 DBT FLRN/PYR C1 FLRN/PYR C2 FLRN/PYR C3 FLRN/PYR C4 FLRN/PYR B(a)A/CHR C1 B(a)A/CHR C2 B(a)A/CHR C3 B(a)A/CHR C4 B(a)A/CHR BFLRN/BPYR C1 BFLRN/BPYR C2 BFLRN/BPYR 33

34 Extended PAH Fingerprint Released Product Pattern Patterns shown as % total graphs.

35 Diagnostic Ratios The relative concentration of specific PAHs can be indicative of a potential source. Often, dibenzothiophene (DBT) is a good indicator for crude products, and the ratio of alkylated DBTs with alkylated phenanthrenes (Phen) is a powerful diagnostic tool.

36 Double Ratio Plot 1.6 Dibenzothiophene / Phenanthrene Diagnos c Ra os Plot 1.4 C4-DBT / C4-Phen Oil Product Upstream of Spill Impacted Area Other Areas C3-DBT / C3-Phen

37 Principle Components Analysis A double ratio plot is good for 4 compounds. But, we can do better we can develop analysis to consider variability within all chemicals Principle Components Analysis (PCA) 37

38 Principal Component Analysis A statistical technique where all variability between samples in a dataset is ordered with the most important differences promoted Reduces dataset to principal components which are driving data variability PCA applications: To demonstrate the similarity or difference between samples in the dataset To indicate the chemicals that drive the differences PCA was carried out on ΣPAH-normalized values This removes the effect of concentration from the dataset Used all measured PAHs in pattern analysis 38

39 Sediment Study - PCA 10 PC Plains Product Product Sample 2013 upstream 2013 POE DS 2013 side channels US 2013 side channels DS 2012 upstream 2012 POE DS 2012 Side channels PC

40 Sediment Study - PCA 10 PC2 Likely impacted side channel sediment samples and product 6 sample. 4 2 Plains Product Product Sample 2013 upstream 2013 POE DS 2013 side channels US 2013 side channels DS 2012 upstream 2012 POE DS 2012 Side channels PC Potentially impacted sample in main river channel -8 40

41 Sediment Study - PCA 10 PC2 Upstream Year Upstream Year Plains Product Product Sample 2013 upstream 2013 POE DS 2013 side channels US 2013 side channels DS 2012 upstream 2012 POE DS 2012 Side channels PC Shift of upstream from 2012 to 2013, new pattern is common throughout study area -8 41

42 Sediment Study - PCA 10 PC2 All 2013 sediment samples group together. Plot away from product sample and 6 impacted 2012 side channel samples Plains Product Product Sample 2013 upstream 2013 POE DS 2013 side channels US 2013 side channels DS 2012 upstream 2012 POE DS 2012 Side channels PC

43 Side Channel Sediment In year 2 of sampling, found small area with entrapped oil Collected sediment for fingerprinting 43

44 Comparison with Product Sample 18% 16% Both Product Entrapped Oil 14% 12% 10% 8% 6% 4% 2% 0% Naphthalene C1 naphthalene C2 naphthalene C3 naphthalene C4 naphthalene Acenaphthene C1 acenaphthene Biphenyl C1 biphenyl C2 biphenyl Fluorene C1 flur ene C2 flur ene C3 flur ene Phenanthrene/Anthracene C1 phenanthrene/anthracene C2 phenanthrene/anth. C3 phenanthrene/anth. C4 phenanthrene/anth. Dibenzothiophene C1 dibenzothiophene C2 dibenzothiophene C3 dibenzothiophene C4 dibenzothiophene Fluoranthene/Pyrene C1 fluoranthene/pyrene C2 fluoranthene/pyrene C3 fluoranthene/pyrene C4 fluoranthene/pyrene Benz(a)anthracene/Chrysene C1 B(a)A/chrysene C2 B(a)A/chrysene C3 B(a)A/chrysene C4 B(a)A/chrysene Benzofluoranthene/Benzopyrene C1 benzofluoranthene/benzopyrene C2 benzofluoranthene/benzopyrene 44

45 Sediment Study - PCA 12 PC New sediment sample Plains Product Product Sample 2013 upstream 2013 POE DS 2013 side channels US 2013 side channels DS 2012 upstream 2012 POE DS 2012 Side channels Recent Sediment PC New sediment sample compares with product sample -8 45

46 Conclusions Guideline exceedances did not provide indication of where oil impacts exist Background PAHs in river are petrogenic Due to large freshet between year 1 and year 2, two background patterns of PAHs identified by PCA PCA was able to distinguish impacted samples from background, even though both are petrogenic Entrapped oil, matched source, 1 year later

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