Many contaminated sites have mixed plumes or contaminants of concern from multiple potential sources. Examples of mixed plumes could include mixed free phase petroleum plumes (e.g. condensate) or polycyclic aromatic hydrocarbons (PAHs) from crude oil spills mixing with upstream or local anthropogenic sources (storm water runoff) of PAHs in sediments. There are several advanced statistical techniques that can be used to determine the number and different sources of contaminant present on the site. In addition, these statistical tools can also apportion the amount of contaminants in each sample, thereby allowing liability to be distributed according the chemistry of the contaminants and those responsible for the release. Apportionment is important for litigious cases as it allows the calculation of who should pay for what portion of the cleanup. Tools using positive matrix factorization (PMF) have been developed by US EPA but are no longer being supported are still publicly available to use. These techniques can be applied to many different chemical mixtures such as condensates or mixed petroleum hydrocarbon plumes. We have successfully applied the technique to PAHs from sediment data to allocate the source of the PAHs in the sediments to sources identified by the models. Unfortunately, these models are not definitive and provide multiple conclusions depending on their starting point which can make interpretation difficult and sometimes questionable, especially for litigation proceedings. This presentation provides a summary of statistical tools used for chemical fingerprinting as well as the use of PMF and Bayesian modelling in order to provide some guidance on model usage for contaminant apportionment. The models need to be applied conservatively and require chemistry interpretation to elucidate what end members have been identified by the model and if those end members make sense. The models will be applied to a real case study scenarios to demonstrate their application. Lawyers, regulators and environmental professionals involved in spill monitoring and liability determination will find this presentation educational in how these statistical models are able to determine sources and amounts of those sources of contaminants on site.

1. © 2018
Chemistry Matters Inc.
Making chemistry data meaningful
Unscrambling Contaminant Mixtures to Determine
their Chemical Fingerprints and Sources
• Court D Sandau1,2, Lacey Harbicht1, Phil Richards1, Khalid Lemouji2
• 1 Chemistry Matters Inc., Calgary, AB
• 2 Statvis Analytics Inc., Edmonton, AB

2. © 2018
Chemistry Matters Inc.
Copyright Statement
All rights reserved. No part of this publication may be reproduced,
distributed, or transmitted in any form or by any means, including
photocopying, recording, or other electronic or mechanical methods,
without the prior written permission of Chemistry Matters Inc.
2Envirotech 2018 - Calgary, Alberta

3. © 2018
Chemistry Matters Inc.
Topics of Presentation
• Environmental forensics and chemical patterns
• What is source apportionment?
• What is Positive Matrix Factorization?
• Case Study – Natural vs. Oil Spill PAHs
Envirotech 2018 - Calgary, Alberta 3

4. © 2018
Chemistry Matters Inc.
Progression of Environmental Forensics
4Envirotech 2018 - Calgary, Alberta
Background Sample 1
PCA HCA
Individual Sample
Pattern Analysis
Double Ratio Plots / Diagnostic Ratios
Chromatogram
Analysis
Next Step:
Source
Apportionment
0.00%
10.0%
50%
35%
2.5% 3.0%
2014_OctNov_AMS09
Source_1 Source_2 Source_3 Oil Sands Source_5 Forest Fire
Sample A

5. © 2018
Chemistry Matters Inc.
Chemical Patterns Are Everywhere
5Envirotech 2018 - Calgary, Alberta
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Aroclor 1248: G3.5
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Aroclor 1254: A4
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12 13 14
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-Z number
Carbon number
Naphthenic Acids in Weathered Oil
0
-2
-4
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PCBs
PAHs
Naphthenic Acids

6. © 2018
Chemistry Matters Inc.
Chemical Fingerprints
6Envirotech 2018 - Calgary, Alberta
Esso
Shell

7. © 2018
Chemistry Matters Inc.
Chemical Patterns
• All contamination has a potential chemical signature
• If the chemical signature is unique to the contamination, then it will
be the fingerprint of the contamination
• There are environmental weathering processes that can alter a
fingerprint over time that must be considered
– BUT - weathering is predictable and is determined by the physical-chemical
properties of the compounds
• Like chemicals – move together in the environment
Envirotech 2018 - Calgary, Alberta 7

8. © 2018
Chemistry Matters Inc.
Source Apportionment
• Determining the proportion of the source(s) of
the contamination in a sample and at a
contaminated site
• Also known as receptor modelling
8Envirotech 2018 - Calgary, Alberta
0.00%
10.0%
50%
35%
2.5% 3.0%
2014_OctNov_AMS09
Source_1 Source_2 Source_3 Oil Sands Source_5 Forest Fire
Sample A
Source of PAHs Based on Toxicity

9. © 2018
Chemistry Matters Inc.
Where can source apportionment be used?
• Air pollution – PAHs, metals on particulate matter, VOCs
• Mixing condensate and gasoline plumes
• Contaminated sites with multiple sources
– Superfund sites – PCBs, PAHs, Dioxins/Furans
• Crude oil spills in rivers and ocean
9Envirotech 2018 - Calgary, Alberta

10. © 2018
Chemistry Matters Inc.
Positive Matrix Factorization (PMF)
• Developed by Paatero (UofHelsinki) for air pollution
• Multivariate technique decomposes a matrix of
analytical results into two matrices:
– factor contributions (how much) and factor profiles
(fingerprint)
• Factor profiles still require interpretation to determine
sources
10Envirotech 2018 - Calgary, Alberta

11. © 2018
Chemistry Matters Inc.
Keys to Successful PMF
• Consistent analytical data for all sampling points
• End-members (sources) well represented in
sampling points included in PMF analysis
• Models are not definitive, multiple conclusions
11Envirotech 2018 - Calgary, Alberta

12. © 2018
Chemistry Matters Inc.
Case Study
12Envirotech 2018 - Calgary, Alberta
PAHs in river after an oil spill

13. © 2018
Chemistry Matters Inc.
Why are PAHs the focus – post oil 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)
• Percentage (<1-10%) quantities in crude oil
– High enough concentrations to see in environment
13Envirotech 2018 - Calgary, Alberta
toluene
3800 Pa
470 mg/L
2.69
10.4 Pa
naphthalene
31 mg/L
3.37
0.0161 Pa
phenanthrene
1.1 mg/L
4.46
0.0006 Pa
pyrene
0.13 mg/L
8.8
Volatility
Solubility
KOC

14. © 2018
Chemistry Matters Inc.
Organic carbon drives sediment concentrations
• Once equilibrium is reached, organic
carbon drives PAH concentrations in
sediments
• Equilibrium is reached quite quickly
14
1979 Publication describes
contaminants sorption to organic
carbon
Envirotech 2018 - Calgary, Alberta

15. © 2018
Chemistry Matters Inc.
PAHs in Rivers
15
• 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
http://www.ec.gc.ca/doc/publications/pollution/COM1396/index-eng.htm
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
N
aphthalene
C1 naphthalene
C2 naphthalene
C3 naphthalene
C4 naphthalene
Fluorene
C1 fluorene
C2 fluorene
C3 fluorene
Phenanthrene/Anthracene
C1 phenanthrene/anthracene
C2 phenanthrene/anth.
C3 phenanthrene/anth.
C4 phenanthrene/anth.
D
ibenzothiophene
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
CTRL S/C-1
Background PAH Pattern
Envirotech 2018 - Calgary, Alberta

16. © 2018
Chemistry Matters Inc.
PAHs on Sediments
• Lots of PAHs in sediments
16Envirotech 2018 - Calgary, Alberta

17. © 2018
Chemistry Matters Inc.
What has more PAHs?
Oil Spill or Yearly Sediment Load?
• Back of the envelope calculation: is a rough calculation, typically
jotted down on any available scrap of paper such as an envelope.
It is more than a guess but less than an accurate calculation or
mathematical proof. (Wikipedia)
17Envirotech 2018 - Calgary, Alberta

18. © 2018
Chemistry Matters Inc. 18Envirotech 2018 - Calgary, Alberta
• Oil spill of 225 m3 which is ~198,000kg
• ∑PAH16 measured concentration of
165 mg/kg
• ∑PAH16 released: 33 kg
• Sediment in large river over 1 year
(mostly during freshet) is 3,000,000
tons
• Average ∑PAH16 measured in
upstream locations was 0.211 mg/kg
• ∑PAH16 in river sediment flowing by
breakpoint each year is 6,330 kg• Oil spill contributes less
than 1% to the yearly
PAHs passing by
breakpoint
Back of the Envelope Calculation
Source apportion that!

19. © 2018
Chemistry Matters Inc.
Setting Up Data for PMF
• CSV files with sample IDs and GPS locations
• CSV file with sample IDs, compound concentrations
• Compound data needs imputations for missing values
– Zero to maximum for missing values
– Kaplan-Meyer substitution for NDs
• Data normalization completed in PMF
19Envirotech 2018 - Calgary, Alberta

20. © 2018
Chemistry Matters Inc.
Geospatial Analysis
and Selection
• Selection tool for selecting
specific data points to look
at
20Envirotech 2018 - Calgary, Alberta

21. © 2018
Chemistry Matters Inc.
Correlation/Heatmap Analysis
• Heatmap shows what compounds are related
21Envirotech 2018 - Calgary, Alberta

22. © 2018
Chemistry Matters Inc.
Principal Component Analysis
• Explore the samples driving variability of your dataset
22Envirotech 2018 - Calgary, Alberta
Oil Related Samples
Upstream of POE
Background Signal

23. © 2018
Chemistry Matters Inc.
PMF
23Envirotech 2018 - Calgary, Alberta

24. © 2018
Chemistry Matters Inc.
PMF - Sources
• Identified two background sources and the spilled oil
24Envirotech 2018 - Calgary, Alberta
Petrogenic Background
Petrogenic Background
Source Oil

25. © 2018
Chemistry Matters Inc.
PMF Results
25Envirotech 2018 - Calgary, Alberta
PCA Page
PMF Page
No Source Oil. Good!
Upstream of POE

26. © 2018
Chemistry Matters Inc.
PMF Results
26Envirotech 2018 - Calgary, Alberta
65% of PAHs from
Source Oil
Indicator DBTs of
Source Oil

27. © 2018
Chemistry Matters Inc.
Conclusions
• Provides client (and stakeholders)
confidence in where oil was found
• Allows client to focus on those areas in
follow up cleanup and monitoring
• Clarity in source of PAHs in the samples
as well as provides perspective on the
risk associated with PAHs from the spill
27Envirotech 2018 - Calgary, Alberta

28. © 2018
Chemistry Matters Inc.
Thank you for your attention
Contact Info:
Chemistry Matters Inc.
Court Sandau
Cell: 403.669.8566
Email: csandau@chemistry-matters.com
www.chemistry-matters.com
Visit my website and sign up for email for
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