Polycyclic Aromatic Hydrocarbons in Food Scientific Opinion of the Panel on Contaminants in the ...

114 Pages·2008·0.68 MB·English

The EFSA Journal (2008) 724, 1-114

Polycyclic Aromatic Hydrocarbons in Food1
Scientific Opinion of the Panel on Contaminants in the Food Chain
(Question N° EFSA-Q-2007-136)
Adopted on 9 June 2008

SCIENTIFIC PANEL MEMBERS
Jan Alexander, Diane Benford, Andrew Cockburn, Jean-Pierre Cravedi, Eugenia Dogliotti,
Alessandro Di Domenico, María Luisa Fernández-Cruz, Johanna Fink-Gremmels, Peter Fürst,
Corrado Galli, Philippe Grandjean, Jadwiga Gzyl, Gerhard Heinemeyer, Niklas Johansson,
Antonio Mutti, Josef Schlatter, Rolaf van Leeuwen, Carlos Van Peteghem, Philippe Verger.

SUMMARY
Polycyclic aromatic hydrocarbons (PAHs) constitute a large class of organic compounds that are
composed of two or more fused aromatic rings. They are primarily formed by incomplete
combustion or pyrolysis of organic matter and during various industrial processes. PAHs
generally occur in complex mixtures which may consist of hundreds of compounds. Humans are
exposed to PAHs by various pathways. While for non-smokers the major route of exposure is
consumption of food, for smokers the contribution from smoking may be significant. Food can be
contaminated from environmental sources, industrial food processing and from certain home
cooking practices.
In the past decade PAHs were evaluated by the International Programme on Chemical Safety
(IPCS), the Scientific Committee on Food (SCF) and by the Joint FAO/WHO Expert Committee
on Food Additives (JECFA). SCF concluded that 15 PAHs, namely benz[a]anthracene,
benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene,
benzo[a]pyrene, chrysene, cyclopenta[cd]pyrene, dibenz[a,h]anthracene, dibenzo[a,e]pyrene,

1 For citation purposes: Scientific Opinion of the Panel on Contaminants in the Food Chain on a request from the
European Commission on Polycyclic Aromatic Hydrocarbons in Food. The EFSA Journal (2008) 724, 1-114.
© European Food Safety Authority, 2008
Polycyclic Aromatic Hydrocarbons in Food

dibenzo[a,h]pyrene, dibenzo[a,i]pyrene, dibenzo[a,l]pyrene, indeno[1,2,3-cd]pyrene and 5-
methylchrysene show clear evidence of mutagenicity/genotoxicity in somatic cells in
experimental animals in vivo and with the exception of benzo[ghi]perylene have also shown clear
carcinogenic effects in various types of bioassays in experimental animals. Thus, SCF reasoned
that these compounds may be regarded as potentially genotoxic and carcinogenic to humans and
therefore represent a priority group in the assessment of the risk of long-term adverse health
effects following dietary intake of PAHs. SCF suggested to use benzo[a]pyrene as a marker of
occurrence and effect of the carcinogenic PAHs in food, based on examinations of PAH profiles
in food and on evaluation of a carcinogenicity study of two coal tar mixtures in mice.
Using the assessments of IPCS and SCF as starting points and taking into account newer studies,
the JECFA re-evaluated PAHs in 2005. Overall, the JECFA concluded that 13 PAHs are clearly
genotoxic and carcinogenic. Except benzo[ghi]perylene and cyclopenta[cd]pyrene the
compounds were the same as those stated by SCF. The JECFA also concluded that
benzo[a]pyrene could be used as a marker of exposure to, and effect of, the 13 genotoxic and
carcinogenic PAHs. In addition, the JECFA recommended to include benzo[c]fluorene as a
further compound into future analyses as data on its occurrence in food are still scarce but rat
studies indicate that benzo[c]fluorene may contribute to the formation of lung tumours after oral
exposure to coal tar.
Following a recommendation on the further investigation into levels of PAHs in certain foods
(2005/108/EC)2, eighteen Member States submitted almost 10,000 results for PAH levels in
different food commodities. An evaluation of these data performed by EFSA in June 2007 and
updated in June 2008 demonstrated that benzo[a]pyrene could be detected in about 50% of the
samples. However, in about 30% of all the samples other carcinogenic and genotoxic PAHs were
detected despite testing negative for benzo[a]pyrene. Of the individual PAHs, chrysene was most
commonly found in the samples negative for benzo[a]pyrene with the highest level of 242 µg/kg.
In view of these findings, the Commission requested a full review of the 2002 SCF opinion on
PAHs.
The EFSA Panel on Contaminants in the Food Chain (CONTAM Panel) reviewed the available
data on occurrence and toxicity of PAHs. As no new toxicological data could be identified that
would lead to the inclusion of further compounds into the list of priority PAHs, the CONTAM
Panel decided to cover the 15 PAHs identified by SCF in 2002 and additionally benzo[c]fluorene
as suggested by the JECFA in 2005 in the present opinion. Special attention was paid to those
eight carcinogenic and genotoxic PAHs that were measured in the coal tar mixtures used in the
carcinogenicity studies, which provided the basis of the SCF and JECFA risk assessments.

2 OJ L 34, 8.2.2005, p.43
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The CONTAM Panel explored whether a toxic equivalency factor (TEF) approach in the risk
characterisation of the PAH mixtures in food could be applied and concluded that the TEF
approach is not scientifically valid because of the lack of data from oral carcinogenicity studies
on individual PAHs, their different modes of action and the evidence of poor predictivity of the
carcinogenic potency of PAH mixtures based on the currently proposed TEF values. Therefore
the CONTAM Panel concluded that the risk characterisation should be based upon the PAHs for
which oral carcinogenicity data were available, i.e. for benzo[a]pyrene and the other PAHs that
were measured in the two coal tar mixtures used in the carcinogenicity studies of Culp et al.
(1998): benz[a]anthracene, benzo[b]fluoranthene, benzo[k]fluoranthene, benzo[ghi]perylene,
chrysene, dibenz[a,h]anthracene and indeno[1,2,3-cd]pyrene. The CONTAM Panel concluded
that these eight PAHs (PAH8), either individually or in a combination, are currently the only
possible indicators of the carcinogenic potency of PAHs in food.
In total, results from 9714 PAH analyses in 33 food categories/subcategories were evaluated. As
in about 30% of the samples analysed for all 15 priority PAHs as recommended by SCF other
carcinogenic and genotoxic PAHs were detected despite testing negative for benzo[a]pyrene,
individual compounds were grouped and summed in order to check whether their sums would
better reflect the occurrence of carcinogenic and genotoxic PAHs in different food categories.
The selection of the individual PAHs was based on the frequency of their results above the limit
of detection (LOD).
Besides the sum of the above mentioned eight PAHs (PAH8), the sum of benzo[a]pyrene,
chrysene, benz[a]anthracene and benzo[b]fluoranthene (PAH4) as well as the sum of
benzo[a]pyrene and chrysene (PAH2) were calculated. The correlation between PAH2 and PAH4
or PAH8 was 0.92 and between PAH4 and PAH8 was 0.99. Of samples negative for PAH2, 26%
and 18% identified concentrations above the LOD for at least one other PAH for samples tested
for all PAH15 or all PAH8, respectively. The frequency varied between 2% and 9% for the
individual PAHs or PAH combinations. Of samples negative for PAH4, 14% and 6% identified
concentrations above the LOD for at least one other PAH for samples tested for all 15 PAHs or
all PAH8, respectively. The frequency varied between 1% and 6% for the individual PAHs or
PAH combinations. Overall, the Panel concluded that PAH4 and PAH8 were better indicators of
the occurrence of PAHs than PAH2.
For different food categories and subcategories, the data on PAH8, PAH4 and PAH2 were then
used for the exposure calculation as well as the estimation of margins of exposure (MOEs) based
on the bench mark dose lower confidence limit for a 10% increase in the number of tumour
bearing animals compared to control animals (BMDL ).
10
The median dietary exposure across European countries was calculated both for mean and high
dietary consumers and varied between 235 ng/day (3.9 ng/kg b.w. per day) and 389 ng/day (6.5
ng/kg b.w. per day) respectively for benzo[a]pyrene alone, 641 ng/day (10.7 ng/kg b.w. per day)
and 1077 ng/day (18.0 ng/kg b.w. per day) respectively for PAH2, 1168 ng/day (19.5 ng/kg b.w.
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Polycyclic Aromatic Hydrocarbons in Food

per day) and 2068 ng/day (34.5 ng/kg b.w. per day) respectively for PAH4 and 1729 ng/day (28.8
ng/kg b.w. per day) and 3078 ng/day (51.3 ng/kg b.w. per day) respectively for PAH8. The two
highest contributors to the dietary exposure were cereals and cereal products, and sea food and
sea food products.
The CONTAM Panel used a MOE approach based on dietary exposure for average and high level
consumers to benzo[a]pyrene, PAH2, PAH4 and PAH8, respectively and their corresponding
BMDL values derived from the two coal tar mixtures that were used in the carcinogenicity
10
studies of Culp et al. (1998). The resulting MOEs for average consumers were 17,900 for
benzo[a]pyrene, 15,900 for PAH2, 17,500 for PAH4 and 17,000 for PAH8. For high level
consumers, the respective MOEs were 10,800, 9,500, 9,900 and 9,600. These MOEs indicate a
low concern for consumer health at the average estimated dietary exposures. This applies to the
full range of estimates of average exposures across EU Member States (3.1-4.3 ng/kg b.w. per
day, MOEs: 16,300-22,600 for benzo[a]pyrene alone and 23.6-35.6 ng/kg b.w. per day, MOEs:
13,800-20,800 for PAH8). However, for high level consumers the MOEs are close to or less than
10,000, which as proposed by the EFSA Scientific Committee indicates a potential concern for
consumer health and a possible need for risk management action. Comparison of the MOEs
calculated for benzo[a]pyrene, PAH2, PAH4 and PAH8, indicates that PAH2, PAH4 and PAH8
can be used as alternatives to benzo[a]pyrene alone as markers of the carcinogenicity of the
genotoxic and carcinogenic PAHs, and would be equally effective.
The CONTAM Panel concluded that benzo[a]pyrene is not a suitable indicator for the occurrence
of PAHs in food. Based on the currently available data relating to occurrence and toxicity, the
CONTAM Panel concluded that PAH4 and PAH8 are the most suitable indicators of PAHs in
food, with PAH8 not providing much added value compared to PAH4.

Keywords: Polycyclic aromatic hydrocarbons (PAHs), food, occurrence, indicators, exposure,
risk assessment, benchmark dose lower confidence limit (BMDL), margin of exposure (MOE),
toxic equivalency factor (TEF)
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Polycyclic Aromatic Hydrocarbons in Food

TABLE OF CONTENTS
SCIENTIFIC PANEL MEMBERS.........................................................................................................1
SUMMARY........................................................................................................................................1
BACKGROUND AS PROVIDED BY THE EUROPEAN COMMISSION....................................................7
TERMS OF REFERENCE AS PROVIDED BY THE EUROPEAN COMMISSION......................................9
ACKNOWLEDGEMENT.....................................................................................................................9
ASSESSMENT.................................................................................................................................10
1. Introduction...............................................................................................................................10
2. Legislation.................................................................................................................................14
3. Sampling and methods of analysis............................................................................................17
3.1 Sampling..............................................................................................................................17
3.2 Methods of analysis.............................................................................................................18
4. Sources and environmental fate................................................................................................21
4.1 Formation and production...................................................................................................21
4.2 Environmental fate..............................................................................................................23
4.3 Sources of food contamination............................................................................................26
5. Occurrence and patterns of PAHs in food.................................................................................27
5.1 Factors influencing the levels of PAHs in food..................................................................42
5.1.1 Commercial processing techniques..............................................................................42
5.1.2 Home cooking and other small scale cooking practices..............................................47
5.2 Suitable indicators for occurrence of total PAHs................................................................49
6. Food consumption.....................................................................................................................52
7. Human exposure assessment.....................................................................................................56
7.1 Dietary intakes.....................................................................................................................56
7.2 Contributions of different food groups to PAH exposure...................................................58
7.2.1 Mean dietary exposure to PAHs...................................................................................59
7.2.2 Dietary exposure to PAHs for high consumers............................................................60
7.3 Sensitivity analysis of dietary exposure..............................................................................61
7.4 Estimates of non-dietary exposure to PAHs.......................................................................63
7.4.1 Ambient air...................................................................................................................63
7.4.2 Occupational exposure.................................................................................................63
7.4.3 Smoking.......................................................................................................................64
8. Hazard identification and characterisation................................................................................65
8.1 Summary of key data...........................................................................................................65
8.1.1 Toxicokinetics..............................................................................................................65
8.1.1.1 Absorption.............................................................................................................65
8.1.1.2 Distribution............................................................................................................66
8.1.1.3 Metabolism............................................................................................................67
8.1.1.4 Excretion...............................................................................................................71
8.1.1.5 Biomarkers of exposure........................................................................................72
8.1.1.6 Biomarkers of effect..............................................................................................75
8.1.2 Toxicological studies....................................................................................................75
8.1.2.1 Acute and short-term toxicity................................................................................75
8.1.2.2 Reproductive toxicity............................................................................................76
8.1.2.3 Immunotoxicity.....................................................................................................76
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8.1.2.4 Carcinogenicity.....................................................................................................76
8.1.2.5 Genotoxicity..........................................................................................................80
8.1.2.6 Observations in humans........................................................................................80
8.1.3 Dose-response modelling.............................................................................................81
8.1.3.1 Benchmark dose modelling...................................................................................82
8.1.3.2 Benchmark dose calculations for benzo[a]pyrene................................................85
8.1.3.3 Benchmark dose calculations for PAH2...............................................................86
8.1.3.4 Benchmark dose calculations for PAH4...............................................................87
8.1.3.5 Benchmark dose calculations for PAH8...............................................................88
8.1.4 Use of a TEF concept in the risk assessment of mixtures of carcinogenic PAHs........88
9. Risk characterisation.................................................................................................................90
10. Suitable indicators for occurrence and toxicity of genotoxic and carcinogenic PAHs...........91
11. Uncertainty analysis................................................................................................................92
11.1 Assessment objectives.......................................................................................................92
11.2 Exposure scenario.............................................................................................................92
11.3 Exposure model.................................................................................................................93
11.4 Model input (parameters)..................................................................................................93
11.5 Other uncertainties............................................................................................................94
CONCLUSIONS...............................................................................................................................94
RECOMMENDATIONS (INCL. KNOWLEDGE/DATA GAPS)..............................................................97
REFERENCES.................................................................................................................................97
LIST OF ABBREVIATIONS AND ACRONYMS.................................................................................111

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Polycyclic Aromatic Hydrocarbons in Food

BACKGROUND AS PROVIDED BY THE EUROPEAN COMMISSION
Polycyclic aromatic hydrocarbons (PAHs) form a class of diverse organic compounds, each of
them containing two or more aromatic rings. Hundreds of different such compounds may be
formed and released during a variety of combustion and pyrolysis processes and thus the natural
and anthropogenic sources of PAHs in the environment are numerous. PAH compounds are
emitted from the processing of coal, crude oil, petroleum, and natural gas, from production of
aluminium, iron and steel, from heating in power plants and homes (oil, gas, charcoal-fired
stoves, wood stoves), burning of refuse, wood fires, and from motor vehicle exhausts.
Humans can be exposed to PAHs through different routes. For the general population, the major
routes of exposure are from food and inhaled air, while in smokers, the contributions from
smoking and food may be of a similar magnitude. Food can be contaminated by environmental
PAHs that are present in air, soil or water, by industrial food processing methods (e.g. heating,
drying and smoking processes) and by home food preparation (e.g. grilling and roasting
processes).
The Scientific Committee on Food (SCF) reviewed the presence and toxicity of PAHs in food
and issued an opinion on 4 December 20023. SCF concluded that a number of PAHs are
genotoxic carcinogens and recommended that exposure to PAHs should be as low as reasonably
achievable. Fifteen substances were identified as a priority due to their potential genotoxicity
and/or carcinogenicity in humans. SCF also concluded that benzo[a]pyrene may be used as a
marker of occurrence and effect of the carcinogenic PAHs in food, but stressed that data
collection on the whole PAH profile should continue in order to be able to evaluate the
contamination of food commodities and any future change in the PAH profile.
The Joint FAO/WHO Expert Committee on Food Additives (JECFA) performed a risk
assessment on PAHs in 2005 in which it estimated Margins of Exposure (MOE) for PAHs. Based
on these Margins of Exposure the JECFA concluded that PAHs were of low concern for human
health. The JECFA also identified an additional substance, benzo[c]fluorene, as a priority
substance.
In the framework of Council Directive 93/5/EEC, a specific SCOOP task on data collection for
PAH has been performed in 20044. On the basis of SCF opinion and the SCOOP data, the
Commission introduced maximum levels for benzo[a]pyrene for some commodities that are

3 Opinion of the Scientific Committee on Food on the risks to human health of polycyclic aromatic hydrocarbons in
food expressed on 4 December 2002, available at: http://ec.europa.eu/food/fs/sc/scf/out153_en.pdf
4 Report on SCOOP task 3.2.12 "Collection of occurrence data on polycyclic aromatic hydrocarbons in food,
October 2004, available at: http://ec.europa.eu/food/food/chemicalsafety/contaminants/scoop_3-2-
12_final_report_pah_en.pdf. The SCOOP task was carried out in the framework of scientific cooperation with
Member States under Council Directive 93/5/EEC, OJ L 52, 4.3.1993, p.18-21
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significant for human exposure and/or in which high PAH levels were found (e.g. oils and fats,
smoked meats and smoked meat products, smoked fish and smoked fish products, muscle meat of
fish other than smoked, crustaceans, cephalopods, bivalve molluscs and infant foods). The
current Regulation setting maximum levels for PAHs in foodstuffs is Commission Regulation
(EC) No. 1881/20065.
For some foodstuffs high levels were found in the SCOOP report, but data were inconclusive as
to the levels that were reasonably achievable (e.g. dried fruits, food supplements and cocoa
butter). The Commission therefore asked Member States to monitor PAHs (and in particular the
15 priority substances identified by SCF) in Commission Recommendation 2005/108/EC6. EFSA
collected the data submitted in the framework of this monitoring recommendation and reported
the findings in the recent Report "Findings of the EFSA Data collection on Polycyclic Aromatic
Hydrocarbons in Food" of 29 June 2007.
The EFSA report stated that the conclusion made by SCF that benzo[a]pyrene is a good indicator
for PAH occurrence could not be demonstrated by the recent monitoring data from the Member
States. Moreover, in October 2005 EFSA adopted the Margin of Exposure (MOE) approach7 for
substances which are both genotoxic and carcinogenic.
In order to reflect these changes, it is appropriate to request a full review of the 2002 SCF
opinion. Within this general review, a special focus should be given to the question whether or
not benzo[a]pyrene can be maintained as a marker for both occurrence and toxicity of the most
relevant PAHs. The relevance of the 15 priority PAHs as identified by SCF and the additional
PAH identified by the JECFA should be confirmed in the light of any new scientific data that
may have become available since the SCF opinion of 2002.

5 OJ L 364, 20.12..2006, p. 5
6 Commission Recommendation of 4 February 2005 on the further investigation into the levels of polycyclic
aromatic hydrocarbons in certain foods, OJ L 34, 8.2.2005, p. 43-45
7 The EFSA Journal (2005) 282, 1-31
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TERMS OF REFERENCE AS PROVIDED BY THE EUROPEAN COMMISSION
In accordance with Article 29 (1) (a) of Regulation (EC) No 178/2002 the European Commission
asks the European Food Safety Authority to review the scientific opinion on PAH given by the
Scientific Committee on Foods (SCF) of December 2002.
The updated opinion should take into account
• the new occurrence data that were collected by EFSA and reported in the "Report on Findings
of the EFSA Data collection on Polycyclic Aromatic Hydrocarbons in Food" of 29 June 2007
and should contain an updated exposure assessment on basis of these data,
• any other relevant scientific information that may have become available since the SCF
opinion in 2002, including any new toxicological studies,
• the margin of exposure approach (MOE) as adopted by the EFSA Scientific Committee in the
Opinion related to substances which are both genotoxic and carcinogenic. In the updated risk
assessment the MOE approach should be used, if appropriate.
Within the general review, the following more specific questions should also be addressed:
• Can benzo[a]pyrene still be considered as a suitable marker for both occurrence and
carcinogenic effects for the most relevant PAHs ?
• In the event that benzo[a]pyrene can not be maintained as a marker, could other suitable
markers or concepts (e.g. TEF concept) be recommended for the occurrence as well as
toxicity of the most relevant PAHs to be applied in European monitoring and official controls
in order to protect human health ?
• Which are the food commodities in the different Member States that contribute most to the
exposure to the most relevant PAHs and which specific groups of the population are most
exposed?

ACKNOWLEDGEMENT
EFSA wishes to thank the working group members Diane Benford, Jean-Pierre Cravedi, Peter
Fürst, Niklas Johansson, John Christian Larsen, Dieter Schrenk, Rolaf van Leeuwen and Philippe
Verger.

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ASSESSMENT
1. Introduction
Polycyclic aromatic hydrocarbons (PAHs) constitute a large class of organic compounds that are
composed of two or more fused aromatic rings. They solely consist of carbon and hydrogen and
do not contain heteroatoms. PAHs are primarily formed by incomplete combustion or pyrolysis
of organic matter and during various industrial processes. Consequently, the natural and
anthropogenic sources in the environment are numerous. PAHs generally occur in complex
mixtures which may consist of hundreds of compounds. The composition of these mixtures varies
with the generating process.
Humans are exposed to PAHs by various pathways. While for non-smokers the major route of
exposure is consumption of food, for smokers the contribution from smoking may be significant.
Food can be contaminated from environmental sources, industrial food processing and from
certain home food preparation.
In the past decade PAHs were evaluated by the International Programme on Chemical Safety
(IPCS) (WHO/IPCS, 1998), the Scientific Committee on Food (SCF) (EC, 2002) and by the Joint
FAO/WHO Expert Committee on Food Additives (JECFA) (FAO/WHO, 2005).
SCF concluded that 15 out of the 33 PAHs which were considered in their assessment, namely
benz[a]anthracene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene,
benzo[ghi]perylene, benzo[a]pyrene, chrysene, cyclopenta[cd]pyrene, dibenz[a,h]anthracene,
dibenzo[a,e]pyrene, dibenzo[a,h]pyrene, dibenzo[a,i]pyrene, dibenzo[a,l]pyrene, indeno[1,2,3-
cd]pyrene and 5-methylchrysene show clear evidence of mutagenicity/genotoxicity in somatic
cells in experimental animals in vivo and with the exception of benzo[ghi]perylene, have also
shown clear carcinogenic effects in various types of bioassays in experimental animals.
Furthermore, SCF concluded that these compounds may be regarded as potentially genotoxic and
carcinogenic to humans and thus represent a priority group in the assessment of the risk of long-
term adverse health effects following dietary intake of PAHs. SCF estimated a maximum daily
intake of benzo[a]pyrene from food of approximately 6-8 ng/kg b.w. per day for a person
weighing 70 kg. It suggested to use benzo[a]pyrene as a marker of occurrence and effect of the
carcinogenic PAHs in food, based on examinations of PAH profiles in food and on evaluation of
a carcinogenicity study of coal tar mixtures in mice (Culp et al., 1998). Based on this latter study,
a conservative assumption would imply that the carcinogenic potency of total PAHs in foods
would be 10 times of that contributed by benzo[a]pyrene alone. SCF finally stressed that though
it considered benzo[a]pyrene as a marker of carcinogenic PAHs in food, chemical analyses
should continue to collect data on other PAHs in order to be able to evaluate the contamination of
food commodities and any future change in the PAH profile.
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