More Related Content Similar to Future of PAH Monitoring Post Oil Spills (20) More from Chemistry Matters Inc. (20) Future of PAH Monitoring Post Oil Spills1. The Macondo Spill Effect
The Changing Times for PAH Monitoring
Court Sandau, PhD, PChem
Phil Richards, PhD, PChem
CLRA Alberta Chapter AGM
February 27, 2014
2. Talk Summary
• Macondo Spill (Deepwater Horizon oil
spill)
• Crude oil is complex
• What to measure for a spill?
• How do we always end up with
PAHs?
• How to measure PAHs, as a family
(very big family)?
• What is next for PAH monitoring?
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3. Deepwater Horizon Oil Spill
• Began on April 20, 2010
• 780,000 m3 of crude oil released over
87 days
• Initial rig explosion killed 11 people
(injured 17 others)
• US gov’t created $20 billion spill
response fund
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4. Deepwater Horizon Oil Spill
• 400+ cases pending
• Worth estimated at $37.6
billion
• $16 billion Clean Water
Act
• Many cases will rely on
environmental forensics
for link to BP (or other
sources)
Also, $500
million to fund
research
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5. Complexity of Crude Oil?
Conventional GC Analysis
UCM
Unresolved Complex Matter
Nelson et al. Environmental Forensics, 7:33–44, 2006
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7. Complexity of PHCs
How many compounds are in….
• The atmospheric aerosol from a
coniferous forest?
• 50 compounds (Kallio, 2006)
• The volatile fraction of roasted coffee
beans?
• 1,000 compounds (Mondello, 2004)
• Cigarette smoke?
•
6,000 compounds (van Mispelaar, 2005)
• Crude oil?
• 7,500-10,000 compounds (Dalluge, 2002)
• 17,000+
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8. What to Measure in an Oil Spill?
(Compounds with guidelines)
• Benzene, Toluene, Ethyl-Benzene, Xylenes
• Petroleum Hydrocarbon Fractions F1, F2,
F3, and F4
• Polycyclic Aromatic Hydrocarbons (PAHs)
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9. CLRA AB AGM Feb 2014
© 2014 Chemistry Matters Inc.
Free Phase Oil
Dissolved Phase
Phytoplankton
Particle Bound Oil
Walleye
Northern Pike
Small Fish
Rainbow Trout
Mountain Whitefish
Cutthroat Trout
Medium Fish
Large Fish
Brook Trout
Sediment
Zooplankton
Benthic Invertebrates
Sediment
Bottom Feeders
9
10. Weathering
• The influence of physical, chemical
and biological forces on the physical
and chemical composition of
contaminants in the environment
– Volatilization
– Solubilization
– Biodegradation
• biotransformation
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11. Volatility
• For free phase product, related to the
vapour pressure
• High vapour pressure = more volatile
10.4 Pa
12,700 Pa
naphthalene
57,900 Pa
pentane
benzene
20,200 Pa
0.0161 Pa
hexane
3800 Pa
toluene
1880 Pa
phenanthrene
octane
0.0006 Pa
pyrene
Most volatile compounds are gone within weeks of spill
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12. Solubilization
• Moving from oil phase (lipophilic) to
water phase (hydrophilic)
• Driven by:
– Solubility
– Kow (octanol:water partitioning)
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13. 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
1790 mg/L
38 mg/L
31 mg/L
naphthalene
pentane
benzene
9.5 mg/L
1.1mg/L
hexane
470 mg/L
toluene
0.66 mg/L
phenanthrene
octane
Big molecules don’t dissolve in water. Solubility in
competition with Kow.
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0.13mg/L
pyrene
13
14. Octanol:Water Partitioning
• Model for lipid partitioning
• Also works for organic carbon
• Kow = Coctanol / Cwater
• Log scale
• Unitless
2.13
3.37
3.45
naphthalene
pentane
benzene
4.11
4.46
hexane
2.69
toluene
5.18
phenanthrene
octane
Big molecules stay in free phase or bind to organic
matter (i.e. sediment)
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8.8
pyrene
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15. Susceptibility to Biodegradation
Most susceptible
C5-C6 Hydrocarbons
Olefins
n-Alkanes
Monoaromatics
Isoalkanes
Parent PAH > 2 ring
C1-alkyl PAH
C2-alkyl PAH
C3-alkyl PAH
C4-alkyl PAH
Triterpanes
Steranes
Diasteranes
Aromatic Steranes
Porphyrins
N
H
N
N
H
N
Less susceptible
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17. PAHs
•
•
•
•
•
Not very volatile
Not soluble in water
Resist biodegradation
Potential to bioaccumulate
Known toxicity (mediated through Ah
receptor)
• Constitutes low % quantities of crude
oil
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18. US EPA Priority Pollutants
PAH Compounds
LMW
naphthalene
acenaphthylene
anthracene
acenaphthene
2-ring
3-ring
fluoranthene
chrysene
pyrene
benzo[b]fluoranthene
benzo[a]anthracene
4-ring
HMW
benzo[k]fluoranthene
f luorene
phenanthrene
dibenz[a,h]anthracene
benzo[a]pyrene
5-ring
List predates 1977
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benzo[ghi]perylene
indeno[1,2,3-cd]pyrene
6-ring
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20. Additional PAHs
– Biogenic (transformation of natural
precursors)(Tan et al. 1996)
Phenanthrene
Retene
Perylene
– Petrogenic (fossil fuels)
dibenzothiophene
– Pyrogenic (burning of organic materials)
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21. Expanding the List of PAHs
Alkylated-PAHs and Other PAHs
9
10
8
7
2
6
C1-Phenanthrenes
Phenanthrene
1
5
4
3
C2-Phenanthrenes
C3-Phenanthrenes
CH3
CH3
CH3
CH3
CH3
CH3
CH3
(5)
CH3
H2C
H 3C
CH2
CH 3
(30)
C4-Phenanthrenes… (?)
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CH2
(?)
21
23. PAHs
• Although different sizes and shapes,
PAHs move in environment as a
group
• Similar sized compounds behave
similarly
phenanthrene
dibenzothiophene
fluoranthene
anthracene
pyrene
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25. 8
8
6
6
4
4
2
2
0
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BF/BP
C1
C2
14
12
BaA/Chry
C1
C2
C3
C4
10
16
FI/Py
C1
C2
C3
C4
Well 5 – Secondary Source
Diben
C1
C2
C3
C4
18
Phen/An
C1
C2
C3
C4
20
18
F
C1
C2
C3
20
FI/Py
C1
C2
C3
C4
BF/BP
C1
C2
BaA/Chry
C1
C2
C3
C4
22
Bph
C1
C2
22
Acl
C1
14
12
% Total
16
Diben
C1
C2
C3
C4
Phen/An
C1
C2
C3
C4
F
C1
C2
C3
Bph
C1
C2
Acl
C1
Naph
C1
C2
C3
C4
% Total
18
Naph
C1
C2
C3
C4
BF/BP
C1
C2
BaA/Chry
C1
C2
C3
C4
FI/Py
C1
C2
C3
C4
Diben
C1
C2
C3
C4
Phen/An
C1
C2
C3
C4
16
F
C1
C2
C3
Bph
C1
C2
Acl
C1
Naph
C1
C2
C3
C4
% Total
PAH Patterns
22
20
On Site Product
14
12
10
8
6
4
2
0
Well 1 – Primary Source
10
0
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26. More PAHs than you thought…
• There are 100s of parent PAHs to
choose from
• Each PAH has potentially 100s of
alkyl-substituted homologues
• Additional PAHs can help elucidate
source
– remember PAHs are ubiquitous
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27. •
•
•
•
‘New’ PAHs
EPA List of priority PAHs dates back
pre-1977
‘New kids on the block’
Upwards to 40 ‘parent’ PAHs
potentially to monitor
Starting to look at heterocycles (O, N,
S containing)
7H-dibenzo(c,g)carazole
dibenzo(a,h)acridine
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3-methyl chlolanthrene
27
30. Advanced Analyses
2D-GC-TOF-MS
• Routine analyses cannot resolve all the compounds
eluting from a crude sample
• 2D-GC uses 2nd dimension to resolve ‘UCM’
• Compound families group together
• TOF analysis allows library search to identify
unknowns
Diesel
30
32. Middle East Crude Oil Investigation
Alkyl Phenanthrenes/Anthracenes
Alkyl Naphthalenes
Alkyl Benzenes
Alkanes
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33. The Macondo Spill Effect
•
Reddy et al. sampled oil directly above well to conduct
comprehensive characterization
– Gas isotopes, GOR, fluid characteristics, API etc.
– Fingerprinted with 2D-GC-TOF
– Could distinguish between crudes
Reddy et al. 2011, PNAS Early Edition, p.1-6
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34. The Macondo Spill Effect
•
•
•
Hall et al. took 41 samples (slicks, scrapings off rocks,
grasses and debris, sand patties etc)
Oxidized hydrocarbons comprised of more than 50% of
extractable hydrocarbons
Used 2D-GC-TOF of samples compared to oil to assess
weathering of oil spill using chemometric techniques
Hall et al. 2013, Marine
Pollution Bulletin, in
press
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35. Conclusions
• Change is slow but monitoring spills
is about to get much more complex
• More PAHs to be included
• Advanced analytical techniques to
follow?
• Once research begins to wrap up, US
researchers will be looking north
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