EN 15522-2:2023
(Main)Oil spill identification - Petroleum and petroleum related products - Part 2: Analytical method and interpretation of results based on GC-FID and GC-low resolution-MS analyses
General Information
- Abstract
This document specifies a method to identify and compare the compositional characteristics of oil samples. Specifically, it describes the detailed analytical and data processing methods for identifying the characteristics of spill samples and establishing their correlation to suspected source oils. Even when samples or data from suspected sources are not available for comparison, establishing the specific nature (e.g. refined petroleum, crude oil, waste oil, etc.) of the spilled oil still helps to constrain the possible source(s).
This methodology is restricted to petroleum related products containing a significant proportion of hydrocarbon-components with a boiling point above 150 °C. Examples are: crude oils, higher boiling condensates, diesel oils, residual bunker or heavy fuel oils, lubricants, and mixtures of bilge and sludge samples, as well as distillate fuels and blends. While the specific analytical methods are perhaps not appropriate for lower boiling oils (e.g. kerosene, jet fuel, or gasoline), the general concepts described in this methodology, i.e. statistical comparison of weathering-resistant diagnostic ratios, are applicable in spills involving these kinds of oils.
Paraffin based products (e.g. waxes, etc.) are outside the scope of this method because too many compounds are removed during the production process [37]. However, the method can be used to identify the type of product involved.
Although not directly intended for identifying oil recovered from groundwater, vegetation, wildlife/tissues, soil, or sediment matrices, they are not precluded. However, caution is needed as extractable compounds can be present in these matrices that alter and/or contribute additional compounds compared to the source sample. If unrecognized, the contribution from the matrix can lead to false “non-matches”. It is therefore advisable to analyse background sample(s) of the matrix that appear unoiled.
When analysing “non-oil” matrices additional sample preparation (e.g. clean-up) is often required prior to analysis and the extent to which the matrix affects the correlation achieved is to be considered. Whether the method is applicable for a specific matrix depends upon the oil concentration compared to the “matrix concentration”. In matrices containing high concentrations of oil, a positive match can still be concluded. In matrices containing lower concentrations of oil, a false “non-match” or an “inconclusive match” can result from matrix effects. Evaluation of possible matrix effects is beyond the scope of this document.
- Status
- Withdrawn
- Publication Date
- 28-Mar-2023
- Withdrawal Date
- 16-Sep-2026
- Technical Committee
- CEN/TC 19 - Petroleum products, lubricants and related products
- Drafting Committee
- CEN/TC 19/WG 9 - Chromatographic test methods
- Current Stage
- 9960 - Withdrawal effective - Withdrawal
- Start Date
- 30-Apr-2025
- Completion Date
- 17-Sep-2026
Relations
- Effective Date
- 31-May-2017
- Effective Date
- 12-Feb-2025
- Effective Date
- 25-Aug-2026
- Effective Date
- 25-Aug-2026
- Effective Date
- 28-Jan-2026
- Effective Date
- 23-Aug-2023
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Frequently Asked Questions
EN 15522-2:2023 is a standard published by the European Committee for Standardization (CEN). Its full title is "Oil spill identification - Petroleum and petroleum related products - Part 2: Analytical method and interpretation of results based on GC-FID and GC-low resolution-MS analyses". This standard covers: This document specifies a method to identify and compare the compositional characteristics of oil samples. Specifically, it describes the detailed analytical and data processing methods for identifying the characteristics of spill samples and establishing their correlation to suspected source oils. Even when samples or data from suspected sources are not available for comparison, establishing the specific nature (e.g. refined petroleum, crude oil, waste oil, etc.) of the spilled oil still helps to constrain the possible source(s). This methodology is restricted to petroleum related products containing a significant proportion of hydrocarbon-components with a boiling point above 150 °C. Examples are: crude oils, higher boiling condensates, diesel oils, residual bunker or heavy fuel oils, lubricants, and mixtures of bilge and sludge samples, as well as distillate fuels and blends. While the specific analytical methods are perhaps not appropriate for lower boiling oils (e.g. kerosene, jet fuel, or gasoline), the general concepts described in this methodology, i.e. statistical comparison of weathering-resistant diagnostic ratios, are applicable in spills involving these kinds of oils. Paraffin based products (e.g. waxes, etc.) are outside the scope of this method because too many compounds are removed during the production process [37]. However, the method can be used to identify the type of product involved. Although not directly intended for identifying oil recovered from groundwater, vegetation, wildlife/tissues, soil, or sediment matrices, they are not precluded. However, caution is needed as extractable compounds can be present in these matrices that alter and/or contribute additional compounds compared to the source sample. If unrecognized, the contribution from the matrix can lead to false “non-matches”. It is therefore advisable to analyse background sample(s) of the matrix that appear unoiled. When analysing “non-oil” matrices additional sample preparation (e.g. clean-up) is often required prior to analysis and the extent to which the matrix affects the correlation achieved is to be considered. Whether the method is applicable for a specific matrix depends upon the oil concentration compared to the “matrix concentration”. In matrices containing high concentrations of oil, a positive match can still be concluded. In matrices containing lower concentrations of oil, a false “non-match” or an “inconclusive match” can result from matrix effects. Evaluation of possible matrix effects is beyond the scope of this document.
This document specifies a method to identify and compare the compositional characteristics of oil samples. Specifically, it describes the detailed analytical and data processing methods for identifying the characteristics of spill samples and establishing their correlation to suspected source oils. Even when samples or data from suspected sources are not available for comparison, establishing the specific nature (e.g. refined petroleum, crude oil, waste oil, etc.) of the spilled oil still helps to constrain the possible source(s). This methodology is restricted to petroleum related products containing a significant proportion of hydrocarbon-components with a boiling point above 150 °C. Examples are: crude oils, higher boiling condensates, diesel oils, residual bunker or heavy fuel oils, lubricants, and mixtures of bilge and sludge samples, as well as distillate fuels and blends. While the specific analytical methods are perhaps not appropriate for lower boiling oils (e.g. kerosene, jet fuel, or gasoline), the general concepts described in this methodology, i.e. statistical comparison of weathering-resistant diagnostic ratios, are applicable in spills involving these kinds of oils. Paraffin based products (e.g. waxes, etc.) are outside the scope of this method because too many compounds are removed during the production process [37]. However, the method can be used to identify the type of product involved. Although not directly intended for identifying oil recovered from groundwater, vegetation, wildlife/tissues, soil, or sediment matrices, they are not precluded. However, caution is needed as extractable compounds can be present in these matrices that alter and/or contribute additional compounds compared to the source sample. If unrecognized, the contribution from the matrix can lead to false “non-matches”. It is therefore advisable to analyse background sample(s) of the matrix that appear unoiled. When analysing “non-oil” matrices additional sample preparation (e.g. clean-up) is often required prior to analysis and the extent to which the matrix affects the correlation achieved is to be considered. Whether the method is applicable for a specific matrix depends upon the oil concentration compared to the “matrix concentration”. In matrices containing high concentrations of oil, a positive match can still be concluded. In matrices containing lower concentrations of oil, a false “non-match” or an “inconclusive match” can result from matrix effects. Evaluation of possible matrix effects is beyond the scope of this document.
EN 15522-2:2023 is classified under the following ICS (International Classification for Standards) categories: 13.020.40 - Pollution, pollution control and conservation; 75.080 - Petroleum products in general. The ICS classification helps identify the subject area and facilitates finding related standards.
EN 15522-2:2023 has the following relationships with other standards: It is inter standard links to CEN/TR 15522-2:2012, EN 15522-2:2023+A1:2025, ISO 1998-1:1998, ISO 16703:2004, EN 15522-1:2023, EN 15522-2:2023/FprA1. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
EN 15522-2:2023 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.
Standards Content (Sample)
SLOVENSKI STANDARD
01-junij-2023
Nadomešča:
SIST-TP CEN/TR 15522-2:2013
Prepoznavanje razlitij olj - Nafta in sorodni naftni proizvodi - 2. del: Analizne
metode in podajanje rezultatov, izhajajočih iz GC-FID in GC-MS nizke ločljivosti
Oil spill identification - Petroleum and petroleum related products - Part 2: Analytical
method and interpretation of results based on GC-FID and GC-low resolution-MS
analyses
Identifizierung von Ölverschmutzungen - Rohöl und Mineralölerzeugnisse - Teil 2:
Analytische Methodik und Interpretation der Ergebnisse, basierend auf GC-FID- und GC-
MS-Analysen bei niedriger Auflösung
Identification des pollutions pétrolières - Pétrole et produits pétroliers - Partie 2 :
Méthode d'analyse et interprétation des résultats sur la base des analyses par CPG DIF
et CPG-SM faible résolution
Ta slovenski standard je istoveten z: EN 15522-2:2023
ICS:
13.020.40 Onesnaževanje, nadzor nad Pollution, pollution control
onesnaževanjem in and conservation
ohranjanje
13.060.99 Drugi standardi v zvezi s Other standards related to
kakovostjo vode water quality
75.080 Naftni proizvodi na splošno Petroleum products in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 15522-2
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2023
EUROPÄISCHE NORM
ICS 13.020.40; 75.080 Supersedes CEN/TR 15522-2:2012
English Version
Oil spill identification - Petroleum and petroleum related
products - Part 2: Analytical method and interpretation of
results based on GC-FID and GC-low resolution-MS
analyses
Identification des pollutions pétrolières - Pétrole et Identifizierung von Ölverschmutzungen - Rohöl und
produits pétroliers - Partie 2 : Méthode d'analyse et Mineralölerzeugnisse aus dem Wasser - Teil 2:
interprétation des résultats sur la base des analyses Analytische Methodik und Interpretation der
par CPG DIF et CPG-SM faible résolution Ergebnisse, basierend auf GC-FID- und GC-MS-
Analysen bei niedriger Auflösung
This European Standard was approved by CEN on 25 December 2022.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 15522-2:2023 E
worldwide for CEN national Members.
Contents Page
European foreword . 8
Introduction . 10
1 Scope . 12
2 Normative references . 12
3 Terms and definitions . 13
3.1 General. 13
3.2 Sample comparison . 15
3.3 Abbreviations . 15
4 Strategy for the identification of oil spill sources . 16
4.1 General. 16
4.2 Basis for reliable conclusions – Numerical comparisons . 17
5 General lab instructions . 18
5.1 Sampling and sample preparation . 18
5.2 GC-FID and GC-MS analysis . 18
5.3 Conclusions and reporting . 20
6 Sample preparation . 20
6.1 General. 20
6.2 Visual examination and description of samples . 20
6.3 Preparation . 21
6.3.1 Sample storage . 21
6.3.2 Water samples . 21
6.3.3 Oil samples from an Ethylene-tetrafluorethylene (ETFE) net . 22
6.3.4 Thick oil and emulsified oil samples . 22
6.3.5 Tar balls and emulsified lumps . 22
6.3.6 Samples from oiled birds, fish and other animals and vegetation . 23
6.3.7 Sediment . 23
6.4 Sample clean-up . 23
6.4.1 General. 23
6.4.2 Particle removal . 23
6.4.3 Asphaltenes precipitation . 24
6.4.4 Alumina column clean-up of biogenic materials . 24
6.4.5 Silica or Florisil® column clean-up . 25
6.5 Recommended injection concentration . 26
7 Characterization and evaluation of analytical data . 27
7.1 General. 27
7.2 Characterization by GC-FID – Level 1 . 28
7.2.1 General. 28
7.2.2 Evaluation of the influence of weathering on sample comparison . 28
7.2.3 Acyclic isoprenoids ratios – Level 1.2 . 31
7.2.4 Level 1 criteria . 32
7.2.5 Level 1 conclusions . 32
7.3 Characterization by GC-MS – Level 2 . 32
7.3.1 General. 32
7.3.2 Visual inspection and overall characterization - Level 2.1 . 32
7.3.3 Treatment of the GC-MS results – Level 2.2 . 33
7.4 Treatment of the results using the MS-PW-plot– Level 2.2 . 33
7.4.1 General . 33
7.4.2 PW-plot calculations . 34
7.4.3 Evaluation of the variability of the analysis and peak integration . 34
7.4.4 Evaluation of weathering . 36
7.5 Treatment of the results using diagnostic ratios – Level 2.2 . 37
7.5.1 General . 37
7.5.2 Diagnostic ratios calculation . 38
7.5.3 Normative diagnostic ratios . 38
7.5.4 Analytical error . 42
7.5.5 Match-criterion for ratios . 43
7.5.6 Criteria for selecting, eliminating and evaluating diagnostic ratios . 44
7.6 Conclusions . 48
8 Reporting . 49
8.1 General . 49
8.2 Internal documentation – technical report . 50
8.3 Identification report – summary report . 51
9 Quality assurance . 51
Annex A (normative) GC-FID analysis . 53
A.1 General . 53
A.2 Analytical standards for GC-FID analyses . 53
A.2.1 N-alkanes . 53
A.2.2 Injection concentration of the standard GC-FID . 54
A.2.3 Storage of frequently used standard solutions . 54
A.3 Suggested instrumental conditions . 54
A.4 Measures to improve and verify the accuracy of the method – GC-FID . 55
A.4.1 Mass discrimination . 55
A.4.2 Column resolution . 56
A.4.3 Linearity . 58
A.4.4 Mid-level concentration . 58
A.4.5 Variance . 59
A.4.6 GC-FID sequence. 59
Annex B (normative) GC-MS analysis . 60
B.1 General . 60
B.2 Analytical standards for GC-MS analyses . 60
B.2.1 General . 60
B.2.2 Crude oil to be used around each sequence . 61
B.2.3 Oil mixture . 61
B.2.4 Analytical standards for PAH homologues . 61
B.2.5 FAMEs . 62
B.2.6 Storage of frequently used standard solutions . 62
B.3 Suggested instrumental conditions . 62
B.3.1 GC conditions for the exchange of analytical results . 62
B.3.2 GC-MS conditions for full-scan analysis . 64
B.3.3 MS preparation for selected ion monitoring (SIM) analysis . 65
B.4 Measures to improve and verify the accuracy of the GC-MS method . 66
B.4.1 Relative retention time . 66
B.4.2 Mass discrimination . 66
B.4.3 Peak symmetry and column resolution . 66
B.4.4 Patterns . 67
B.4.5 Linearity . 67
B.4.6 Mid-level concentration . 67
B.4.7 Variance. 68
B.4.8 Sample analysis with GC-MS . 68
Annex C (informative) Precision statement . 69
C.1 General. 69
C.2 Precision of the MS-PW-plot . 69
C.3 Precision of the ratio comparison . 70
C.4 Reproducibility . 71
C.5 The effect of the ratio type on the RSD . 72 ®
C.6 Example of a paired ratio calculation in Excel . 73 ®
C.7 Calculation of the evaporation line for the MS-PW-plot in Excel . 74
Annex D (normative) Evaluative reporting using match definitions or likelihood ratios . 77
D.1 General. 77
D.2 Match definitions . 77
D.3 Likelihood ratios (LR) . 78
Annex E (normative) List of compounds and compound groups analysed by GC-MS-SIM . 80
E.1 General. 80
E.2 Compounds. 81
E.2.1 General. 81
E.2.2 Compound type . 86
E.3 Normative ratios and informative ratios. . 87
Annex F (informative) Chromatograms and ratios of compounds and compound groups analysed
by GC-MS-SIM . 91
F.1 General. 91
F.2 Alkanes . 91
F.3 Cyclohexanes and polycyclic alkanes . 92
F.4 Mono-aromatic and poly-aromatic compounds . 98
F.4.1 Alkyl-benzenes and alkyl-toluenes . 98
F.4.2 PAHs, alkyl-PAHs and S-PAHs . 98
F.4.3 Tri-aromatic steranes . 109
F.5 FAMEs . 110
Annex G (informative) General composition of oils – chemical groups . 114
G.1 General . 114
G.2 Hydrocarbons . 115
G.3 Aliphatic compounds . 115
G.3.1 General . 115
G.3.2 Paraffins . 115
G.3.3 Naphthenes . 115
G.4 Aromatic compounds . 116
G.5 Heteroatomic organic compounds . 116
G.5.1 General . 116
G.5.2 Resins . 116
G.5.3 Asphaltenes . 116
Annex H (informative) Weathering of oils spilled on water and land . 118
H.1 General . 118
H.2 Weathering processes . 118
H.2.1 Weathering of oils spilled on water . 118
H.2.2 Weathering of waterborne oils stranded on land or land based oil spills . 120
H.2.3 Mixing and contamination. 120
H.2.4 Dispersion . 121
H.2.5 In-situ burning . 123
H.3 Evaluation of weathering processes . 124
H.3.1 Evaporation . 124
H.3.2 Dissolution . 127
H.3.3 Photo-oxidation . 129
H.3.4 Biodegradation . 135
H.3.5 Wax redistribution . 138
H.3.6 Mixing . 144
H.3.7 Contamination . 146
H.3.8 In-situ burning . 146
Annex I (informative) Characteristic features of different oil types in oil spill identification . 149
I.1 General . 149
I.2 Crude oil . 149
I.2.1 General. 149
I.2.2 Analysis . 150
I.3 Light fuel oil (gas oil, diesel, fuel No 2, biofuels, GTL) . 156
I.3.1 General. 156
I.3.2 Analysis, GC screening . 157
I.3.3 GC-MS analysis . 159
I.3.4 Biofuels . 162
I.3.5 Gas to liquid products . 163
I.4 Lubricating oil . 164
I.4.1 General. 164
I.4.2 Analysis . 166
I.5 Heavy fuel oil (HFO, Bunker C, Fuel No 6) and low sulfur fuel oil . 170
I.5.1 General. 170
I.5.2 Analysis . 171
I.6 Waste oil (bilge oil, sludge, slops) . 179
I.6.1 General. 179
I.6.2 Analysis . 180
I.7 Conclusion . 184
Annex J (informative) Example of external documentation – identification report of an oil spill case
.......................................................................................................................................................................... 186
J.1 General. 186
J.2 Sample information . 186
J.3 Analytical procedure . 186
J.3.1 Method . 186
J.3.2 Dilution/extraction . 186
J.3.3 Analyses. 186
J.4 Results . 186
J.5 Interpretation . 186
J.5.1 General. 186
J.5.2 Positive match . 187
J.5.3 Probable match . 187
J.5.4 Inconclusive . 187
J.5.5 Non-match . 187
J.6 Conclusions . 187
Annex K (informative) Example of internal documentation – technical report of an oil spill case
.......................................................................................................................................................................... 189
K.1 General . 189
K.2 Sample information . 189
K.2.1 Samples . 189
K.2.2 Contact information . 189
K.2.3 Request . 189
K.2.4 Photo(s) of the samples . 190
K.3 Sample preparation and analyses . 190
K.4 Quality assurance . 192
K.5 GC-FID results – Level 1 . 194
K.5.1 GC-FID chromatograms – Level 1.1 . 194
K.5.2 GC-FID numerical comparisons – Level 1.2 . 196
K.5.3 GC-FID conclusions . 201
K.6 GC-MS results – Level 2 . 202
K.6.1 General . 202
K.6.2 GC-MS chromatograms – Level 2.1 . 202
K.6.3 GC-MS numerical comparisons – Level 2.2 . 203
K.6.4 Visual inspection . 211
K.6.5 Overall conclusions . 212
Bibliography . 213
European foreword
This document (EN 15522-2:2023) has been prepared by Technical Committee CEN/TC 19 “Gaseous and
liquid fuels, lubricants and related products of petroleum, synthetic and biological origin”, the secretariat
of which is held by NEN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by September 2023, and conflicting national standards shall
be withdrawn at the latest by September 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document will supersede CEN/TR 15522-2:2012.
In comparison with the previous edition CEN/TR 15522-2:2012, the following technical modifications
have been made:
— adding compounds to be analysed in order to include light products in the diesel range;
— adding more information about biodegradation;
— adding a Reporting and a Quality assurance chapter;
— adding Annex C with precision data;
— adding Annex D with likelihood grade conclusions;
— introduction of characterization of FAME in Annex I;
— serious revision of Annexes H, I, J and K, adding new pictures and chromatograms.
EN 15522 is composed of two parts that describe the following:
— Part 1 on sampling, describing good sampling practice, detailing sampling equipment, sampling
techniques and the handling of oil samples prior to their arrival at the forensic laboratory;
— Part 2 giving the analytical method, which covers the general concepts and laboratory procedures of
oil spill identification, analytical techniques, data processing, data treatment,
interpretation/evaluation and reporting of results.
This document has originally been prepared under a mandate given to CEN by the European Commission
and the European Free Trade Association.
A list of all parts in a series can be found on the CEN website.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organisations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia,
Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the United
Kingdom.
Introduction
This document describes a forensic method for characterizing and identifying the source of oil spills in
the environment resulting from accidents or intentional discharges. By following this method, data
generated can be used as evidence in support of the legal process. This method is based on the experience
gained from use of the earlier revisions.
This document is composed of two parts that describe the following:
— Part 1 on sampling, describing good sampling practice, detailing sampling equipment, sampling
techniques and the handling of oil samples prior to their arrival at the forensic laboratory;
— Part 2 giving the analytical method, which covers the general concepts and laboratory procedures of
oil spill identification, analytical techniques, data processing, data treatment,
interpretation/evaluation and reporting of results.
Oil spill source identification is a complex process due to the large variation in sample types and oil spill
situations that can be encountered. Part 1 is a compilation of instructions and experiences from experts
all over the world which will guide the user in sampling, storing and delivering oil samples for laboratory
analysis. Part 2 will guide the reader through the analytical process. It prescribes how to prepare and
analyse oil samples using Gas Chromatography with Flame Ionization Detection (GC-FID) and GC with
low-resolution Mass Spectrometry (GC-MS). Any compositional difference found between samples is only
relevant if this difference is larger than the variability of the method itself. Good analytical performance
and strict quality assurance are therefore essential. In the Annexes of Part 2, relevant information
concerning different types of oil and oil comparison techniques are presented.
In a typical standard method for testing, instructions are given on performing an “analytical” procedure.
However, oil spill identification comprises both analytical and assessment components. Sample
preparation is described in Chapter 6. Analytical methodology for GC-FID is provided in Annex A, while
GC-MS is covered in Annexes B, E and F. Other parts of the document describe how to assess the analytical
data utilizing various tools to draw a conclusion. As every case can differ in situation, size, products and
weathering, the evaluation part of the method is described as a toolbox. Annexes J and K provide example
documents for an oil spill case and show how the assessment tools may be applied. Further examples of
specific oil spill cases are available as summary reports of the annual round robins (RR-tests) organized
by Bonn-OSINet [11] and in literature.
The purpose of this document is to assist the reader in defensibly identifying the source of an oil spill by
comparing the chemical composition of spill samples against suspected source oils. The basis for this
method is the widely variable chemical compositions of oils, which allows oils from different sources to
be distinguished by analytical techniques. The method relies upon detailed chemical characterization and
statistical comparison between samples (i.e. a spilled oil and a suspected source) diagnostic features in
order to determine whether they “match”. To minimize the danger of “false positive matches”, good
laboratory practices are to be maintained. A “positive match” between a spilled oil and suspected source
sample may not be sufficient to identify the PRP (potential responsible party) on its own. However, this
result can be critical evidence in proving a case within the legal process.
It should be noted that oil spill identification methodologies have limitations and may not necessarily
lead to unequivocal conclusions. In certain cases, neither the oil spill nor suspected source(s) are unique
or homogeneous in nature, e.g. due to the changing/variable nature of oil in bilge tanks or due to mixing
of oils spilled from several sources. For such cases there is a risk that the chemi
...