biogenic interference calculation (bic) index for ... · biogenic interference calculation > 10%...
TRANSCRIPT
Alberta Peatlands
=
False PHC detections in peat soils
surrounding an oil spill
2016 RemTech Conference, Banff Alberta
Biogenic Interference Calculation (BIC) Index for Resolving False Exceedences of AB Tier-1 F3 PHC Soil Guidelines Due to Biogenic Interferences in Peat Soils
Francine Kelly-Hooper, PhD, Soils Scientist
CH2M HILL Canada
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What is the BIC Index?
Pronounced “BIC” like the pen
� Calculation for determining if biogenic interferences have caused organic (peat) samples to falsely exceed the Alberta Tier-1, 300 mg/kg F3 PHC soil guideline.
� [F2/(F2+F3b)] x 100
� <10% = false PHC exceedence
� >10% = true PHC exceedence
2004 - 2016 Research Partners
Imperial OilALS Laboratory Group
Canadian Association of
Petroleum Producers
Husky EnergyAlberta Parks and Protected
Areas Division
Environment Canada Oil
Spills Research Centre
Orphan Well Association
Canadian Geological Survey
Petroleum Technology Alliance of
Canada
(Village that Raised the BIC Index)
Natural Sciences and Engineering
Research Council
University of Waterloo
STUDY OBJECTIVES Comparison of Control Experiment Data to Field Validation Data
To determine if the BIC Index will correctly identify samples that have
or have not falsely exceeded the most stringent Alberta Tier 1 F3 PHC
soil guideline (300 mg/kg) in all clean and contaminated soil samples
Data Set #1: 300-Day Crude Oil Spiked Peat PhD Experiment
Clean peat and sand were spiked with crude oil and studied for biogenic vs petrogenic carbon distributions over time.
Data Set #2: 300-Day Diesel Spiked Manure PhD Experiment
Compost and sand were spiked with diesel drilling invert and studied for biogenic vs petrogenic carbon distributions over time.
Data Set #3: Background PHC survey of 34 sites located in Alberta, BC and Newfoundland
� Canadian Geological Survey collected 34 background soil samples for the biogenic vs petrogenic carbon distribution study
Data Set #4: Orphan Well Association Field Validation Site
� The OWA collected 55 samples from a 35-year old crude oil contaminated Alberta peatland for the biogenic vs petrogenic carbon distribution study.
What are biogenic organic compounds (BOCs)?
� BOCs are carbon-based compounds, which are naturally biosynthesized by living organisms.
� 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.
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.).
The goal is to “capture” petroleum hydrocarbons.
However, background biogenic organic
compounds are inadvertently “captured” as well.
The problem is that the hexane and acetone solvents indiscriminately
extract all carbon from petroleum and biological sources.
Extract
injection
F2, F3, F4
concentrations
quantified by
chromatogram
integrations
) ) ) ) ) ) ) )ion flowflame detector
capillary column
carrier
gas
line
Vaporizer
Oven
Flame Ionization
Detector
electronic
signal
GC-FID Analysis of Sample Extract
Retention Time (minutes)
0
100
200
300
pA
4 5 6 7 8 9 10 11
F4
>C34
F3
C16-C34
F2
C10-C16
UCM
Diesel
F3 2000 mg/kg
Reported F33000 mg/kg Peat
F3 1000 mg/kg
Diesel-Spiked Peat GC-FID Chromatogram
Carbon Numbers
F1 F2 F4
C10 C16C6 C34 >C34
F4C34
F1 F2C10-C16
>
F3C16-C34C6-C10
Biogenic Organic Compounds
(e.g. fatty acids, sterols, waxes, etc. )
Gasoline
Diesel/No. 2 Fuel Oil
Crude Oil
No. 6 Oil/Lube Oil/Heavy fuels, Tar, Asphalts
Classification of Petroleum Hydrocarbon Sources by Carbon Number Range
Comparison of Background Soil Survey Results to
Alberta Tier-1 Soil and Groundwater Remediation Guidelines
Alberta Tier-1 Soil Remediation Guidelines
“Coarse textured soil remediation
guidelines may be used for organic
contaminants in organic soils”
34 Background Soil Samples: Alberta, BC, Newfoundland
0
400
800
1200
1600
F3 (
mg
/kg
)Comparisons of F2, F3, F4 Concentrations to AB Tier-1 Soil Remediation Guidelines
Surface Soils Natural/Agricultural/Residential/Parkland Guidelines
16 samples (47%) exceeded
F3 coarse soil standard300 mg/kg
0
50
100
150
200
F2 (
mg
/kg
)
0 samples exceeded
F2 course soil standards150 mg/kg
%TOC
0
1000
2000
3000
0% 10% 20% 30% 40%
F4 (
mg
/kg
)
0 samples exceeded F4
course soil standards
2800 mg/kg
0
400
800
1200
1600
F3 (
mg
/kg
)
16 samples (47%) exceeded
F3 coarse soil standard300 mg/kg
0
50
100
150
200
F2 (
mg
/kg
)
0 samples exceeded
F2 course soil standards150 mg/kg
34 Background Soil Samples: Alberta, BC, NewfoundlandComparisons of F2, F3, F4 Concentrations to AB Tier 1 Soil Remediation Guidelines
Surface Soils Natural/Agricultural/Residential/Parkland Guidelines
Only F3 exceeded the guideline
Biogenic Interference Calculation for Identifying False Exceedences of the AB Tier-1, F3 PHC 300 mg/kg Soil Guideline
Formula
F2 = measured F2 (C10-C16) concentration
[F2/(F2+F3b)] x 100
F3b = measured F3b (C22-C34) concentration
Index Values
<10% indicates that BOCs have caused false exceedences of F3 PHC guideline
>10% indicates true exceedences of the F3 PHC guideline
Non-detectable F2
Detectable F2
Detectable F2
F3a (C16-C22) and F3b (C22-C34) Distributions in Diesel and Clean Peat
F3a
F2 Total F3 F4
Carbon NumberC16C10 C22 C34
Clean Peat
7% F3a93% F3b
11% F3b
89% F3a
F3b
63%
F3a
37%
Diesel
Diesel Contaminated
Peat
F3b(C16-C22) (C22-C34)
Non-detectable F2
Detectable F2
Detectable F2
F3a (C16-C22) and F3b (C22-C34) Distributions in Crude Oil and Clean Peat
F2 Total F3 F4
Crude + Peat
Carbon Number
C16C10 C22 C34
Peat
69% F3b
31% F3a
F3a F3b(C16-C22) (C22-C34)
FederatedCrude Oil
50% F3b
50% F3a
7% F3a 93%
F3b
13 Crude Oil Samples
% o
f T
ota
l F
3 C
on
cen
trati
on
0
25
50
75
100
13 Fresh Crude Oil Samples 34 Background Soil Samples
34 Soil Samples
0
25
50
75
100
% o
f T
ota
l F
3 C
on
cen
trati
on
F3a (C16-C22) F3b (C23-C34)F3a (C16-C22) F3b (C23-C34)
Median
F3b 93%
F3a 7%F3b 51%
F3a 49%
Median
1 2 3 4 5 6 7 8 9 10 11 12 13
F2, F3, F4, F3a, F3b Carbon Distributions in PHC Products and Clean Peat
F3a F3b
F2 F3 F4
Tar
Engine Oil
Crude Oil
Diesel Fuel
Peat 7% F3a 93%
F3b
F3a 89%
F3b 11%
53% F3b
47% F3a
6% F3a
94% F3b
14% F3a
86% F3b
High F3a
High F3a
Low F3a
Low F3a
Low F3a
Carbon NumberC16C10 C22 C34
Clean Peat
Diesel
Diesel Spiked
Peat
69%
33%
F2
F2 = 823 mg/kg
F3b = 371 mg/kg
F2 = 613 mg/kg F3b = 2,816 mg/kg
F2 = 10 mg/kg F3b = 1,395 mg/kg
F3b
= Guideline Exceedence
[F2/F2+F3b] x 100
1% = Guideline not
Exceeded
= Guideline Exceedence
Example of BIC Index for Diesel PHCs
Total F3
F2
Total F3
Carbon NumberC16C10 C22 C34
Clean Peat
F2 = 10 mg/kg
F3b = 1,000 mg/kg
1%
Crude Oil Spiked
Peat
F2 = 1,000 mg/kg
F3b = 2,000 mg/kg 33%
F3b
Crude Oil
F2 = 1,000 mg/kg
F3b = 1,200 mg/kg
45%
= Guideline not Exceeded
= Guideline Exceeded
= Guideline Exceeded
[F2/F2+F3b] x 100
Example of BIC Index for Crude Oil PHCs
No Yes
Does the GC-FID chromatogram image have an obvious
Unresolved Complex Mixture (UCM) petrogenic pattern?
No
Heavy PHCs may be present
(Do not proceed with the evaluatio)
Indicates false exceedance
of F3 PHC guideline
BIC Index Decision Tree for Identifying False Exceedences of AB Tier-1 F3 PHC 300 mg/kg Soil Guideline
Indicates true exceedance
of F3 PHC guideline
Is the Biogenic Interference Calculation >10%?
Yes
Pre-screening criteria: only include samples that meet these criteria
1) F2 concentration is less than laboratory method detection limit (<20 mg/kg)
2) F3 concentration exceeds the 300 mg/kg guideline, F4 concentration does not exceed any guidelines
3) The released PHC product(s) must extend into the light F2 (C10-C16) carbon range (e.g. diesel, crude oil, etc.)
4) A qualified person must confirm that the GC-FID chromatogram does not have a heavy PHC pattern (e.g. asphalt, bitumen, motor oil, etc.).
Bio
gen
ic In
terf
ere
nce
Calc
ula
tio
n
> 10% indicates true F3 PHC
guideline exceedences
<10% indicates false F3 PHC
guideline exceedences
Peat spiked with crude oil;
compost spiked with diesel invert Clean soils and compost
BIC Index Testing of Control Samples: Clean and Spiked Soil and Compost
Bio
gen
ic In
terf
ere
nce
Calc
ula
tio
n
> 10% indicates true F3 PHC
guideline exceedences
<10% indicates false F3 PHC
guideline exceedences
Peat spiked with crude oil;
compost spiked with diesel invert Clean soils and compost
• BIC Index correctly identified true F3 PHC guideline exceedences in all crude
oil and diesel spiked samples
• BIC Index correctly identified false F3 PHC guideline exceedences in all
clean samples
BIC Index Testing of Control Samples: Clean and Spiked Soil and Compost
Bio
gen
ic In
terf
ere
nce
Calc
ula
tio
nField Validations of 37 Year Old OWA Crude Oil Contaminated Peatland
Peat samples with detectable F2 and
>300 mg/kg F3 concentrations
Peat samples with non-detectable F2 and
>300 mg/kg F3 concentrations
> 10% indicates true F3 PHC
guideline exceedences
<10% indicates false F3 PHC
guideline exceedences
Bio
gen
ic In
terf
ere
nce
Calc
ula
tio
nField Validations of 37 Year Old OWA Crude Oil Contaminated Peatland
Peat samples with detectable F2 and
>300 mg/kg F3 concentrations
Peat samples with non-detectable F2 and
>300 mg/kg F3 concentrations
> 10% indicates true F3 PHC
guideline exceedences
<10% indicates false F3 PHC
guideline exceedences
• All samples with >300 mg/kg F3 and non-detectable F2 concentrations
were identified as false PHC guideline exceedences
• All samples with >300 mg/kg F3 and detectable F2 concentrations were
identified as true PHC guideline exceedences
BIC Index Statistical Probability Test Results
The BIC Index is a highly conservative/cautious tool.
0% probability of missing true exceedences.
10% probability of missing false exceedences.
Next Steps?
� CH2M is currently expanding the BIC Index to include heavy PHCs
(e.g. asphalt, bitumen, motor oil, etc.) as well.