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Directorate-General for Health and Food Safety
Opinion (revised) on Cancer risk to consumers from Creosote containing less than 50 ppm benzo-[a]-pyrene and/or from wood treated with such Creosote and estimation of respective magnitude expressed at the 8th CSTEE plenary meeting, Brussels, 4 March 1999.
1. Introduction
2. Dermal Carcinogenicity Study of Two Coal Tar Products (CTP)
3. An Evaluation of the Carcinogenicity of Coal-Tar Derived Creosote
4. Foundation of the Appeal against the EC-directive on Creosote
5. Study on the Justification in Scientific Terms of Allowing the Netherlands to retain its National Laws on Creosote in Place of Council Directive 94/60/EEC
6. Position of the Government of the Federal Republic of Germany
7. Karlehagen Epidemiology Study
8. Evaluation of German Exposure Estimates by ERM (Environmental Resource Management, London)
9. Human Health and Environmental Concerns of Creosote
10. Report to the Commission of the European Union by SORGO consultant
11. Study on the Justification in Scientific Terms of Allowing Sweden to retain its National Laws on Creosote in Place of Council Directive 94/60/EEC
12. Conclusion
1. Introduction
Marketing and use of Creosote and preparations containing Creosote as well as creosote-treated wood has been regulated by the Directive 94/60/EC. The provisions are based on the classification for Creosote laid down in Directive 94/69/EC which is an adaptation of Directive 67/548/EEC on the approximation of the laws, regulations, and administrative provisions relating to the classification, packaging and labelling of dangerous substances.
Classification regarding carcinogenicity of Creosote was based on the content of benzo[a]pyrene (BaP), because this PAH was chosen as a marker substance for the classification of coal tar-derived mixtures. According to Directive 94/60/EC classification of such mixtures including Creosote as carcinogens is not necessary if the BaP content is lower than 50 ppm. Accordingly no restrictions in sale or use exist for Creosote containing less than 50 ppm BaP. Creosote containing 50 - 500 ppm may not be sold to consumers and can be used in industrial installations. Wood treated with such Creosote can only be used for professional and industrial applications. Use of such Creosote is prohibited inside buildings, in contact with plants or food and on playgrounds.
Several Member States (NL, D, DK and S) held the opinion that the level of protection for human health and the environment was insufficient and requested to maintain their more restrictive national legislations. However, except The Netherlands, where a particulate geographic situation prevails, these Member States failed to submit any substantive evidence that the level of protection of the Community Directive was insufficient.
The Commission and the Member States made a joint declaration that the classification of Creosote would be reviewed once the results on an ongoing carcinogenicity study of Creosote would be known which was carried out at that time by the Fraunhofer Institute (FhG) in Hannover/Germany. The results of this study are now available.
The dermal carcinogenicity study and the national justifications to maintain the more strict national regulations have been submitted to the Scientific Committee of Toxicity, Ecotoxicity and the Environment to advise the Commission on the following questions:
1. Is there sufficient scientific evidence to support the opinion that there is a cancer risk to consumers from Creosote containing less than 50 ppm benzo[a]pyrene and/or from wood treated with such Creosote?
2. If such a risk exists, can its magnitude be estimated or quantified?
2. Dermal Carcinogenicity Study of Two Coal Tar Products (CTP), CSTEE/98/10-Add 1:
In a 78 week study groups of 62 male mice were treated dermally with two different preparations of coal tar oil containing either 10 ppm or 300 ppm BaP (CTP1 and CPT2, resp.) twice a week on the clipped skin. CPT1 and CPT2 were administered biweekly amounts of 1, 3 or 9 mg per animal per treatment. The resulting amounts of BaP are given in Table 1 including the amounts of BaP of the positive control group.
Table 1: Study design of the dermal carcinogenicity study in mice
using 2 coal tar oil preparations (CTP1 and CTP2)
The following findings were documented:
CPT1:
No skin tumours were seen in the 1 mg and 3 mg dose groups which corresponded to the application of 0.01 and 0.03 m g BaP. At 3 mg (0.03 m g BaP) 1 solitary squamous cell carcinoma was observed, 2 solitary squamous cell papillomas in the 9 mg (0.09 m g BaP) group. However, those incidences were not statistically different from the control group. Regarding non-neoplastic histopathological endpoints, no statistically significant deviations were found. However, an increase in ulcerated skin after 3 mg per treatment and above was observed, and decrease in skin erythema at 9 mg. At that dose mean life span was not statistically significant decreased from 494 days in the untreated control group to 447 days.
CPT2:
An increased incidence in squamous cell skin carcinoma occurred after treatment with 3 mg (0,8 m g BaP) and above, skin papilloma starting at 1 mg (0.27 m g BaP) and multiple papillomas at the highest dose of 9 mg (2.4 m g BaP). The mean life span was significantly decreased after treatment with 1 mg, 3 mg and 9 mg from 494 days in the control to 444, 407, and 252 days, respectively.
Overall, the study showed a dose-dependent increase of malignant and non-malignant skin tumours after CTP2 treatment and a non-statistically significant increase in total skin tumours at the highest dose after CTP1 treatment.
These results agree with the previously shown carcinogenic potential of coal tar extracts. The potency of the different Creosote doses applied to the skin correlated directly with the BaP contents, corroborating the convention to relate the carcinogenic potential of a mixture to the marker substance BaP. The highest CTP2-dose of 9 mg per application also supported this relationship when the reduced survival time of these animals was taken with consideration. (This becomes evident when the incidence is the reduced treatment time.)
Moreover, as compared to the amount of BaP content in the Creosote products, the tumour inducing potency of the CTP2 formulation was about five times higher than that observed with BaP alone in the positive control (Table 2). This observation has not been further investigated. It may either be due to the presence of other carcinogenic compounds in the CTP or that the carcinogenic effect of BaP has reached a plateau at lower concentrations which have not been tested in the present investigation.
Table 3: Potency of CTP 2 related to BaP-contents as compared to the potency of the positive BaP-control
x ) Terminated after 274 days because of severe skin lesions
The T25 carcinogenic potency value for BaP in this experiment can be calculated to be 13 µg/kg bw/day (CSTEE/98/10-Add. 16). The CTP formulation tested here had a five-fold higher carcinogenic potency relative to its BaP content (2.7 µg/kg bw/day).
3. An Evaluation of the Carcinogenicity of Coal-Tar Derived Creosote, CSTEE/98/10-Add. 2 (International Tar Association):
The International Tar Association presented some information on the composition of different Creosote products. Those produced at high temperature have until recently contained concentrations of BaP around 0.1 % (1000 ppm). It is, however, claimed that most Creosote products produced in the EU today contain less than 50 ppm BaP.
There is also an interesting comparison between the two products tested in the Fraunhofer Institute study (CSTEE/98/10-Add.1). One of these (CTP 1) contained 10ppm BaP and the other (CTP 2) 271 ppm, a factor of 27 between the two products. The concentrations of benzo(a)anthracene were 25 and 1190, respectively, giving a factor of 48, and another potent carcinogen, dibenzo(a,h)anthracene, was determined at 1 and 19.2 ppm, respectively.
The paper gives some comments on the mouse skin painting study and contrasts it with human exposure situations. In the mouse experiment the same treated area is painted over and over again, the mouse does not wash the material off and toluene is used as a solvent in the painting experiment. It was concluded by the authors that it describes a worst case situation.
4. Foundation of the Appeal against the EC-directive on Creosote, CSTEE/98/10-Add. 3 (Position of the Netherlands):
In The Netherlands approximately 10,000 kilometres of water banks are protected with creosote-treated timber. The leaching of creosote from this application is considered one of the major sources of pollution of sediments with PAH.
In 1990 about 100,000 m 2 of wood has been treated in The Netherlands with approx. 9,000 tonnes of Creosote, mainly applied for bank protection, railway sleepers, fencing and fruit tree support. About 1,100 tonnes of coal tar varnish has been applied by private persons and farmers. Emission of BaP to water, soil and air from the use of coal tar oil preparations in The Netherlands have been calculated.
The annual emissions during Creosote production and storage are 100 - 150 kg, in the usage phase 256 kg to soil, 212 to air and 133 kg to surface water. In the sediments of governmental and regional waters of more than 90 % of the samples the limit value of 0.05 mg BaP/kg d. s. is exceeded. About 80 % of this pollution is estimated to come from Creosote used for water bank protection. This is considered to be an unacceptable risk to the aquatic ecosystem, to higher species and possibly to man. The Netherlands therefore have not accepted the proposal of the 14th Amendment to the EC directive 76/769/EEC that Creosote for preserving wood for industrial installations may contain a maximum of 500 ppm BaP, and instead only allows a maximum of 50 ppm irrespective of the method of treatment. Moreover the Netherlands has restricted the use of Creosote and coal tar varnish regardless of the content of BaP. This is in contrast to the directive, which does not restrict the use of Creosote, containing less than 50 ppm BaP. The Dutch position is that this is expected to reduce exposure of the 3 high risk groups: the employees in Creosote plants, the neighbouring residents of Creosote production sites and children, who may get into contact with Creosote when playing on materials made of Creosote-treated wood by oral or skin contact.
Risk assessment of oral exposure. The approach has been to assess how much Creosote from contaminated soil in contact with creosoted wood a child may maximally ingest, given the Dutch maximum permissible daily dose of 12 m g benzo(a)pyrene (B(a)P)/kg bodyweight/day. Using this a 15 kg child may ingest maximally 3.6 g of Creosote with 50 ppm B(a)P. It is judged that consuming such an amount by a child is unlikely for a child by way of hand-mouth contact. Even if this risk assessment is based on B(a)P, and not Creosote which in the skin-painting experiments was 5 times as potent as B(a)P (ref. the Fraunhofer study, CSTEE/98/10-Add. 1), this judgement should be valid.
Risk assessment of dermal exposure Here one has used exposure data from an occupational study where assembly workers came into skin contact with creosoted wood. Exposure to children in contact with creosoted wood has been calculated simply by converting the occupational data on pyrene (a component of Creosote) by relating it to the smaller skin surface area, lower exposure periods and lower body weights. In addition, a direct conversion from pyrene to B(a)P was undertaken under the assumption that exposure to B(a)P was directly proportional to pyrene relative to their concentrations in Creosote. A calculation according to a dermal exposure scenario in children of 20 ng B(a)P/kg bw/day was compared to the Dutch permissible dermal dose limit in children of 1.6 ng/kg B(a)P/kg bw/day based on tumorigenicity data from mice. Since the exposure exceeded the limit, the risk was judged to be unacceptable. Note that there is a miscalculation in this report in that the dermal exposure should be 2 ng BaP/kg bw/day rather than 20 ng BaP/kg bw/day (see point 5, CSTEE/98/10-Add. 4).
The exposure assessment may be overestimated since the exposure is given as amount deposited on the skin, not the amount taken up into the body after dermal absorption. There may be differences in the degree of dermal absorption of Creosote between humans and mice. Further, the exposure assessment may be overestimated since one has assumed that exposure to B(a)P is directly proportional to that of pyrene. On the other hand, the risk assessment is underestimated since it is based upon B(a)P carcinogenicity and not data from the Fraunhofer study with Creosote.
5. Study on the Justification in Scientific Terms of Allowing the Netherlands to retain its National Laws on Creosote in Place of Council Directive 94/60/EEC, CSTEE/98/10-Add. 4 (Grimmer):
This is a review of CSTEE/98/10-Add. 3 with critical comments to the assessments and evaluations therein. In the Appendix 3 of the Dutch foundation of the appeal (CSTEE/98/10-Add.3) there is a miscalculation in the estimation of the daily exposure to BaP. The correct amount should be 0.163 µg rather than 1.63 µg. The correct figure results in a daily dose of 2 ng BaP/kg bw/day. It gives some data on the content of selected PAH in Creosote and presents a table of carcinogenic potencies of various PAH relative to B(a)P. However, it does not specifically give any new exposure data or risk assessments of children exposed to creosoted wood in playgrounds. Therefore, this report will not be further commented upon.
6. Position of the Government of the Federal Republic of Germany, CSTEE/98/10-Add. 5, including CSTEE/98/10-Add. 6 (MAK documentation):
In Germany the designation Creosote is used only for 9 different liquid by-products of the burning of coal or wood. The regulations for these formulations are based on the content of BaP and on contents of water-soluble phenols. If the content of phenols or BaP exceed 3% or 500 ppm, respectively, the production and use are prohibited. Formulations with a BaP content between 50 and 500 ppm may only be used for wood treatment in industrial processes. Sale, including that to private consumers, is only permitted at a BaP content up to 50 ppm. There are also regulations for the use and marketing of treated wood products.
All other tar oil-containing formulations are not allowed for sale to private consumers irrespective of their BaP content. For professional use there are various restrictions. Formulations containing up to 5 ppm BaP may only be used in closed plants. Higher contents are permitted for novel impregnation together with a final vacuum or re-heating. 50 to 500 ppm BaP formulations are permitted for the treatment of railway sleepers and electricity poles. Manufacture, use and marketing of products containing more than 500 ppm is prohibited. Marketing and use of the treated wood products is also regulated.
The more strict regulations of tar oil products have been justified by the classification of BaP and of PAH-containing mixtures as animal carcinogens by the German MAK-Committee (CSTEE/98/10-Add.6), the high carcinogenic potency of the PAH constituents and the limited possibility to quantify the carcinogenic risk of human exposure. Nevertheless a three times per week skin contact of children for 5 years with wood treated with tar oil containing 25% BaP has been estimated to result in a 2% lifetime risk of cancer development. This risk assessment has been based on a dermal carcinogenicity study in mice, which received 50 m l of a solution containing 25 ppm and 50 ppm BaP three times a week. The lower concentration induced tumours in 44%, the higher in 95% of the animals.
7. Karlehagen Epidemiology Study, CSTEE/98/10-Add. 7:
Cancer incidence was studied among 922 creosote-exposed impregnators at 13 plants in Sweden and Norway. The total cancer incidence observed was lower than expected, with 129 cases observed versus 137 expected. The excess of cancer of the lip (5 observed vs. 2.05 expected) is of borderline statistical significance (in Table 1, footnote reports p=0.05 whereas 95 % confidence interval in first line includes unity). The excess of non-melanoma skin cancer was statistically significant, and is biologically plausible, being concentrated in those working 10+ years and being related to a cancer site which has been previously suspected as a target site of the same agent. On the other hand, the potential biases correctly suggested by the authors cannot be ruled out.
8. Evaluation of German Exposure Estimates by ERM (Environmental Resources Management, London), CSTEE/98/10-Add. 8:
The evaluation of the German position regarding exposure and of additional data leads to the conclusion that the German population is not directly exposed to unusually high doses of Creosote through products sold to customers and through contact with Creosote-treated timber, nor is the German aquatic environment exposed to unusually high levels of PAHs coming from Creosote-treated wood.
While little data were available concerning the exposure of German workers to Creosote, it is considered likely that exposure levels are comparable to those in other Member States. It is considered unlikely that German Workers are exposed to unusually high levels of Creosote in comparison to other workers in other Member States.
9. Human Health and Environmental Concerns of Creosote, CSTEE/98/10-Add.9 (Danish Position):
The Danish Authorities describe that Creosote is not approved for use in Denmark, although it has been used for more than a century. About 10,000 tonnes of Creosote is, however, produced in the country and exported to Sweden, Norway and Germany. These products are claimed to contain less than 50 ppm BaP.
A study of Creosote composition in impregnated poles after 40 years of use is described. Substances with the lowest boiling point showed the highest migration and the part of the poles above ground had lost the largest amounts. Creosote components could only be detected in soil in close contact with the pole.
The possibility of ground water contamination is mentioned, but the data on measured concentrations of Creosote components were restricted to contaminated sites.
It is claimed that the Danish climate will decrease the importance of degradation, both photolytic and microbial, as compared to other countries in the EU.
10. Report to the Commission of the European Union by SORGO consultant, CSTEE/98/10-Add. 10 (Position of Denmark):
P. M. Sorgo has evaluated the contribution from the Danish Authorities (CSTEE/98/10-Add. 9). In summary, he found that the Danish population is not exposed to unusually high doses of PAH from the use of Creosote, neither from treated wood or via ground water consumption. These conclusions were, however, based on the present situation when no Creosote is used in the country.
11. Study on the Justification in Scientific Terms of Allowing Sweden to retain its National Laws on Creosote in Place of Council Directive 94/60/EEC, CSTEE/98/10-Add. 11:
This is a very detailed and transparent report of high quality. In contrast to CSTEE/98/10-Add. 3, one has here assessed exposure in children by calculating the amount absorbed into the body based on skin absorption rate data for pyrene from a human coal-tar ointment study. The calculated uptake of B(a)P was 0.85 ng/kg bw/day, and thus substantially lower than the calculated exposure in CSTEE/98/10-Add. 3 (20 ng/kg bw/day). A large part of this difference is due to the fact that here the absorbed dose, and not the dose applied on the skin, was calculated. This report has used a permissible dose of 4.8 ng/kg bw/day (and not 1.6 ng/kg bw/day as in CSTEE/98/10-Add. 3) since the exposure period was set to 2 hours a day for six months (and not 3 hours a day for a whole year). It was judged that the cancer risk to children from direct exposure to Creosote from contact with creosote-treated wood will not be unacceptable (disproportionally high), since the uptake was less than the permissible dose for this scenario.
The exposure assessment scenario involving the private use of creosote-treated wood and treatment of untreated wood with Creosote for construction purposes provided an uptake of B(a)P of 47 ng/kg bw/day. This was correlated to the Dutch permissible daily dose for B(a)P via skin exposure for an adult member of the general public of 2.1 m g/kg bw/day (recalculated with an exposure period of 8 hours per day for two weeks every year). Also this exposure was judged not to be unacceptably (disproportionally) high.
In this case the exposure assessment relies on a number of assumptions, which may or may not hold true (these are clearly presented in the text). In addition, the exposure may be underestimated since the calculations have used mean absorption rates for pyrene, and not maximum values (12 vs 23 pmol/cm²/hr). On the other hand, the exposure assessment may be overestimated since one has assumed that absorption of B(a)P is directly proportional to that of pyrene. In contrast, the risk assessment is underestimated since it is based upon B(a)P carcinogenicity and not data from the Fraunhofer study with Creosote.
12. Conclusion
Creosote is a coal tar product, which contains varying amounts of PAHs and other mutagenic and carcinogenic substances. Coal tar products including Creosote are classified as potential human carcinogens (EU: Category 2, IARC: 2A). This is mainly based on several positive skin painting studies in mice as well as some suggestive epidemiological evidence in humans. Due to the genotoxic potential of PAHs including BaP and other components of coal tar the carcinogenic potential cannot be considered thresholded. As a consequence the carcinogenic risk of exposure is considered linearly dose-dependent so that each exposure is also associated with a certain risk even at low doses.
The carcinogenic potential of coal tar preparations has been reaffirmed by a skin painting study performed by the Fraunhofer Institute. The CSTEE concludes that this is a well-designed study which clearly indicates a linear dose response relation to the BaP content of the administered substances. Both preparations (CPT1 and CPT2) have a five-fold higher potency to induce skin tumours than BaP, presumably due to the presence of other substances than BaP in Creosote. It can be inferred from the Fraunhofer study that Creosote containing 50 ppm BaP would induce a significant incidence of skin cancer in mice.
Data to fully evaluate the relevance of effects seen in a mouse skin painting study for human exposure situations are insufficient. Species dependent sensitivity of dermal exposure to the carcinogenic actions of Creosote will be affected by morphology and physiology of the skin, by metabolic activation and inactivation in the skin and by repair processes. Moreover the precision of the human exposure estimates presented in the different reports is debatable. On the basis of the available information, a scientifically justified assessment of carcinogenic risk e.g. for the dermal exposure of children playing on wood treated with Creosote is therefore difficult.
Exposure of children from dermal contact with creosote-treated wood has been estimated from either occupational studies of pyrene or a coal-tar ointment study, and recalculated with respect to BaP. These two estimates are fairly similar (2 vs 0.85 ng BaP/kg bw/day). The CSTEE concludes that these estimates are quite uncertain, but that they give an indication of the possible dimension of the actual exposure. Annual intakes of BaP from food has been estimated to be in the order of 0.3 - 1.6 mg (Fritz) 1971; Jacob and Grimmer 1996; Santodonato et al. 1979; Strubelt 1986). This would result in daily exposures of 12 - 63 ng/kg bw for a person weighing 70 kg.
Extrapolating skin carcinogenicity data from mice to the human situation also entails a number of uncertainties leading to difficulties in directly using cancer potency data from mice to assess cancer risk in humans. However, based on linear extrapolation of the potency of Creosote revealed in the Fraunhofer study, the lifetime risk from the calculated exposure estimates of approximately 1 ng BaP/kg bw/day would be in the order of 10 -4. Such a risk level gives clear reason for concern.
The Scientific Committee of Toxicity, Ecotoxicity and the Environment concludes the following:
1. Given the genotoxicity of BaP and the outcome of the Fraunhofer skin painting study, there is sufficient scientific evidence to support the opinion that there is a cancer risk to consumers from Creosote containing less than 50 ppm BaP and/or from wood treated with such Creosote.
BaP is a good indicator for the carcinogenic hazard of the Creosote preparation tested, since there was a linear relationship between cancer incidence and BaP dose. However, the cancer potency of the Creosote preparation was 5-fold higher than judged from its BaP content.
2. On the basis of the available information, even taking into account the considerable uncertainties in assessing the risks for children coming into contact with Creosote-treated wood, the magnitude of the risk gives clear reasons for concern. However, the highest estimated exposure is some 6-30 times lower than the oral exposure of the adult population to BaP in food.
In order to get a better estimate of the exposure situation, one would have to perform a real-life, mass-balance study in exposed children. In addition to being very complicated and resource intensive, to conduct such a study would raise ethical questions.
Annex
List of documents made available to the Scientific Committee on Toxicity, Ecotoxicity and the Environment via its Secretariat to help it reach the opinion requested by the services of the Commission on the subject:
'Cancer risk to consumers from Creosote containing less than 50 ppm benzo-[a]-pyrene and/or from wood treated with such Creosote and estimation of respective magnitude'
CSTEE/98/10
Hazardous properties of Creosote.
Note from Mr. P. Ortùn (Director III/C) to Mr. B. Carsin (Director XXIV/B) dated 20/3/98 - Ref. 005846.
CSTEE/98/10 - Add. 1
Dermal Carcinogenicity Study of two Coal Tar Products (CTP) by Chronic Epicutaneous Application in Male CD-1 Mice (78 weeks)
Final report made by the Fraunhofer Institute of Toxicology and Aerosol Research (Hannover).
CSTEE/98/10 - Add. 2
An Evaluation of the Carcinogenicity of Coal-Tar derived Creosote
Submitted by the International Tar Association (UK) - 29/12/1997.
CSTEE/98/10 - Add. 3
Foundation of the appeal against the EC-directive on creosote
Made by bkh consulting engineers on request of the Dutch Ministry of Housing, Spatial Planning and Environment - Delft (NL) 11/7/1995.
CSTEE/98/10 - Add. 4
Study on the Justification in Scientific Terms of Allowing the Netherlands to retain its National Laws on Creosote in Place of Council Directive 94/60/EEC
Made by Prof. Dr.G. Grimmer(Biochemisches Institüt für Umweltcarcinogene - Germany) on request of the European Commission (contract no. ETD/95/84066).
CSTEE/98/10 - Add. 5
Report of the Government of the Federal Republic of Germany of 19 June 1995 concerning Directive 94/60/EC of the EP and of the Council of 20/12/94 on the 14 th amendment to Directive 76/769/EEC for alignment of the legal and administrative regulations of the Member States for restricting the marketing and use of certain hazardous substances and formulations (OJ No. L 365 of 31/12/94, p. 1).
Submitted by the German Authorities in support of their request under Art. 100a (4).
CSTEE/98/10 - Add. 6
A report from theGerman MAK Commission on the suitability of Benzo[a]pyrene as a marker substance "Polycyclische Aromatische Kohlenwasserstoffe, krebserzeugende (PAH)" and its translation into English "Polycyclic aromatic hydrocarbons, carcinogenic (PAH)".
CSTEE/98/10 - Add. 7
Cancer incidence among creosote-exposed workers
From the Scand. J. Work Environ. Health - 1992.
CSTEE/98/10 - Add. 8
Study on the Scientific Evaluation of the German Request for a Derogation from the Provisions of Council Directive 94/60/EC concerning creosote (April 1996).
Made by ERM Consultants on request of the European Commission (contract no. ETD/95/84081).
CSTEE/98/10 - Add. 9
A report "Human Health and Environmental Concerns of Creosote" (5/12/1995)
Submitted by the Danish Authorities in support of their request under Art. 100a (4) - 5/12/1995.
CSTEE/98/10 - Add. 10
Study on the Justification in Scientific Terms of Allowing Danmark to retain its National Laws on Creosote in Place of Council Directive 94/60/EEC
Made by Dr. Sorgo (Consultant) on request of the European Commission (contract no. ETD/96/84094) - 20/11/1996 - and an additional letter from Dr. Sorgo.
CSTEE/98/10 - Add. 11
Study on the Justification in Scientific Terms of Allowing Sweden to retain its National Laws on Creosote in Place of Council Directive 94/60/EEC
Made by WS ATKINS Consultants on request of the European Commission (contract no. ETD/96/500069) - August 1997.
CSTEE/98/10 - Add. 12
Creosote - draft outline report for CSTEE information
CSTEE/98/10 - Add. 13
Evaluation of a Dermal Carcinogenicity Study with Mice with Two Different Creosotes.
Report from Fraunhofer-Institute of Toxicology and Aerosol Research (Hannover) - May 1998.
Document transmitted by Mr. P. Buigues (DG III).
CSTEE/98/10 - Add. 14
T25: A Simplified Carcinogenic Potency Index: Description of the System and Study of Correlations between Carcinogenic Potency and Species/Site Specificity and Mutagenicity.
Report from E. Dybing - January 1997.
CSTEE/98/10 - Add. 15
Potency considerations regarding Creosote.
Report from Prof. Jansson - 4/8/1998.
CSTEE/98/10 - Add. 16
Creosote - Comments from Erik Dybing.
Report from E. Dybing - 31/8/1998.
CSTEE/98/10 - Add. 17
Fritz, W. (1971) Umfang und Quellen der Kontamination unserer Lebensmittel mit krebserzeugenden Kohlenwasserstoffen, Ernähruungsforsch, XVI, 4, 547-557.
CSTEE/98/10 - Add. 18
Jacob, J. und Grimmer, G. (1996) Metabolism and excretion of polycyclic aromatic hydrocarbons in rat and in human. Centr. Eur. J. publ. Hlth 4, Suppl. p. 33-39.
CSTEE/98/10 - Add. 19
Santodonato, J., Basu, D. und Howard, P.H. (1979) Multimedia human exposure and carcinogenic risk assessment for environmental PAH, Polynuclear Aromatic Hydrocarbons, Chemistry and Biological Effects. Bjorseth, A. and Dennis A. J. (Eds.), Battelle Press, Columbus, Ohio, 435-454.
CSTEE/98/10 - Add. 20
Strubelt, O. (1986) Über das Viorkommem und die Bedeutung von Karzinogen in der menschlichen Umwelt. Dt. Apoth. Z. 126, 1977.
1. Introduction
2. Dermal Carcinogenicity Study of Two Coal Tar Products (CTP)
3. An Evaluation of the Carcinogenicity of Coal-Tar Derived Creosote
4. Foundation of the Appeal against the EC-directive on Creosote
5. Study on the Justification in Scientific Terms of Allowing the Netherlands to retain its National Laws on Creosote in Place of Council Directive 94/60/EEC
6. Position of the Government of the Federal Republic of Germany
7. Karlehagen Epidemiology Study
8. Evaluation of German Exposure Estimates by ERM (Environmental Resource Management, London)
9. Human Health and Environmental Concerns of Creosote
10. Report to the Commission of the European Union by SORGO consultant
11. Study on the Justification in Scientific Terms of Allowing Sweden to retain its National Laws on Creosote in Place of Council Directive 94/60/EEC
12. Conclusion
1. Introduction
Marketing and use of Creosote and preparations containing Creosote as well as creosote-treated wood has been regulated by the Directive 94/60/EC. The provisions are based on the classification for Creosote laid down in Directive 94/69/EC which is an adaptation of Directive 67/548/EEC on the approximation of the laws, regulations, and administrative provisions relating to the classification, packaging and labelling of dangerous substances.
Classification regarding carcinogenicity of Creosote was based on the content of benzo[a]pyrene (BaP), because this PAH was chosen as a marker substance for the classification of coal tar-derived mixtures. According to Directive 94/60/EC classification of such mixtures including Creosote as carcinogens is not necessary if the BaP content is lower than 50 ppm. Accordingly no restrictions in sale or use exist for Creosote containing less than 50 ppm BaP. Creosote containing 50 - 500 ppm may not be sold to consumers and can be used in industrial installations. Wood treated with such Creosote can only be used for professional and industrial applications. Use of such Creosote is prohibited inside buildings, in contact with plants or food and on playgrounds.
Several Member States (NL, D, DK and S) held the opinion that the level of protection for human health and the environment was insufficient and requested to maintain their more restrictive national legislations. However, except The Netherlands, where a particulate geographic situation prevails, these Member States failed to submit any substantive evidence that the level of protection of the Community Directive was insufficient.
The Commission and the Member States made a joint declaration that the classification of Creosote would be reviewed once the results on an ongoing carcinogenicity study of Creosote would be known which was carried out at that time by the Fraunhofer Institute (FhG) in Hannover/Germany. The results of this study are now available.
The dermal carcinogenicity study and the national justifications to maintain the more strict national regulations have been submitted to the Scientific Committee of Toxicity, Ecotoxicity and the Environment to advise the Commission on the following questions:
1. Is there sufficient scientific evidence to support the opinion that there is a cancer risk to consumers from Creosote containing less than 50 ppm benzo[a]pyrene and/or from wood treated with such Creosote?
2. If such a risk exists, can its magnitude be estimated or quantified?
2. Dermal Carcinogenicity Study of Two Coal Tar Products (CTP), CSTEE/98/10-Add 1:
In a 78 week study groups of 62 male mice were treated dermally with two different preparations of coal tar oil containing either 10 ppm or 300 ppm BaP (CTP1 and CPT2, resp.) twice a week on the clipped skin. CPT1 and CPT2 were administered biweekly amounts of 1, 3 or 9 mg per animal per treatment. The resulting amounts of BaP are given in Table 1 including the amounts of BaP of the positive control group.
Table 1: Study design of the dermal carcinogenicity study in mice
using 2 coal tar oil preparations (CTP1 and CTP2)
| ID | No. | Sex | Group Name | Treatment twice a week with 25 m l of a toluenic solution |
| 01 | 62 | Male | Negative control (toluene) (Solvent control) | 25 m l toluene per treatment |
| 02 | 62 | Male | Positive control B(a)P | 7.5 m g B(a)P |
| 03 | 62 | Male | Low dose CTP 1 | 1 mg CTP 1 D 0.01 m g B(a)P |
| 04 | 62 | Male | Medium dose CTP | 3 mg CTP 1 D 0.03 m g B(a)P |
| 05 | 62 | Male | High dose CTP 1 | 9 mg CTP 1 D 0.09 m g B(a)P |
| 06 | 62 | Male | Low dose CTP 2 | 1 mg CTP 2 D 0.27 m g B(a)P |
| 07 | 62 | Male | Medium dose CTP 2 | 3 mg CTP 2 D 0.80 m g B(a)P |
| 08 | 62 | Male | High dose CTP 2 | 9 mg CTP 2 D 2.4 m g B(a)P |
The following findings were documented:
CPT1:
No skin tumours were seen in the 1 mg and 3 mg dose groups which corresponded to the application of 0.01 and 0.03 m g BaP. At 3 mg (0.03 m g BaP) 1 solitary squamous cell carcinoma was observed, 2 solitary squamous cell papillomas in the 9 mg (0.09 m g BaP) group. However, those incidences were not statistically different from the control group. Regarding non-neoplastic histopathological endpoints, no statistically significant deviations were found. However, an increase in ulcerated skin after 3 mg per treatment and above was observed, and decrease in skin erythema at 9 mg. At that dose mean life span was not statistically significant decreased from 494 days in the untreated control group to 447 days.
CPT2:
An increased incidence in squamous cell skin carcinoma occurred after treatment with 3 mg (0,8 m g BaP) and above, skin papilloma starting at 1 mg (0.27 m g BaP) and multiple papillomas at the highest dose of 9 mg (2.4 m g BaP). The mean life span was significantly decreased after treatment with 1 mg, 3 mg and 9 mg from 494 days in the control to 444, 407, and 252 days, respectively.
Overall, the study showed a dose-dependent increase of malignant and non-malignant skin tumours after CTP2 treatment and a non-statistically significant increase in total skin tumours at the highest dose after CTP1 treatment.
These results agree with the previously shown carcinogenic potential of coal tar extracts. The potency of the different Creosote doses applied to the skin correlated directly with the BaP contents, corroborating the convention to relate the carcinogenic potential of a mixture to the marker substance BaP. The highest CTP2-dose of 9 mg per application also supported this relationship when the reduced survival time of these animals was taken with consideration. (This becomes evident when the incidence is the reduced treatment time.)
Moreover, as compared to the amount of BaP content in the Creosote products, the tumour inducing potency of the CTP2 formulation was about five times higher than that observed with BaP alone in the positive control (Table 2). This observation has not been further investigated. It may either be due to the presence of other carcinogenic compounds in the CTP or that the carcinogenic effect of BaP has reached a plateau at lower concentrations which have not been tested in the present investigation.
Table 3: Potency of CTP 2 related to BaP-contents as compared to the potency of the positive BaP-control
|
positive BaP
control |
||||||
| mg CTP 2 | 0.1 | 0.3 | 1 | 3 | 9 x | |
| m g BaP | 0.03 | 0.08 | 0.27 | 0.8 | 2.4 | 7.4 |
| Skin tumours | 1 | 3 | 9 | 23 | 20 | 47 |
|
Tumours
per m g BaP | 33 | 38 | 33 | 29 | 8 | 6 |
x ) Terminated after 274 days because of severe skin lesions
The T25 carcinogenic potency value for BaP in this experiment can be calculated to be 13 µg/kg bw/day (CSTEE/98/10-Add. 16). The CTP formulation tested here had a five-fold higher carcinogenic potency relative to its BaP content (2.7 µg/kg bw/day).
3. An Evaluation of the Carcinogenicity of Coal-Tar Derived Creosote, CSTEE/98/10-Add. 2 (International Tar Association):
The International Tar Association presented some information on the composition of different Creosote products. Those produced at high temperature have until recently contained concentrations of BaP around 0.1 % (1000 ppm). It is, however, claimed that most Creosote products produced in the EU today contain less than 50 ppm BaP.
There is also an interesting comparison between the two products tested in the Fraunhofer Institute study (CSTEE/98/10-Add.1). One of these (CTP 1) contained 10ppm BaP and the other (CTP 2) 271 ppm, a factor of 27 between the two products. The concentrations of benzo(a)anthracene were 25 and 1190, respectively, giving a factor of 48, and another potent carcinogen, dibenzo(a,h)anthracene, was determined at 1 and 19.2 ppm, respectively.
The paper gives some comments on the mouse skin painting study and contrasts it with human exposure situations. In the mouse experiment the same treated area is painted over and over again, the mouse does not wash the material off and toluene is used as a solvent in the painting experiment. It was concluded by the authors that it describes a worst case situation.
4. Foundation of the Appeal against the EC-directive on Creosote, CSTEE/98/10-Add. 3 (Position of the Netherlands):
In The Netherlands approximately 10,000 kilometres of water banks are protected with creosote-treated timber. The leaching of creosote from this application is considered one of the major sources of pollution of sediments with PAH.
In 1990 about 100,000 m 2 of wood has been treated in The Netherlands with approx. 9,000 tonnes of Creosote, mainly applied for bank protection, railway sleepers, fencing and fruit tree support. About 1,100 tonnes of coal tar varnish has been applied by private persons and farmers. Emission of BaP to water, soil and air from the use of coal tar oil preparations in The Netherlands have been calculated.
The annual emissions during Creosote production and storage are 100 - 150 kg, in the usage phase 256 kg to soil, 212 to air and 133 kg to surface water. In the sediments of governmental and regional waters of more than 90 % of the samples the limit value of 0.05 mg BaP/kg d. s. is exceeded. About 80 % of this pollution is estimated to come from Creosote used for water bank protection. This is considered to be an unacceptable risk to the aquatic ecosystem, to higher species and possibly to man. The Netherlands therefore have not accepted the proposal of the 14th Amendment to the EC directive 76/769/EEC that Creosote for preserving wood for industrial installations may contain a maximum of 500 ppm BaP, and instead only allows a maximum of 50 ppm irrespective of the method of treatment. Moreover the Netherlands has restricted the use of Creosote and coal tar varnish regardless of the content of BaP. This is in contrast to the directive, which does not restrict the use of Creosote, containing less than 50 ppm BaP. The Dutch position is that this is expected to reduce exposure of the 3 high risk groups: the employees in Creosote plants, the neighbouring residents of Creosote production sites and children, who may get into contact with Creosote when playing on materials made of Creosote-treated wood by oral or skin contact.
Risk assessment of oral exposure. The approach has been to assess how much Creosote from contaminated soil in contact with creosoted wood a child may maximally ingest, given the Dutch maximum permissible daily dose of 12 m g benzo(a)pyrene (B(a)P)/kg bodyweight/day. Using this a 15 kg child may ingest maximally 3.6 g of Creosote with 50 ppm B(a)P. It is judged that consuming such an amount by a child is unlikely for a child by way of hand-mouth contact. Even if this risk assessment is based on B(a)P, and not Creosote which in the skin-painting experiments was 5 times as potent as B(a)P (ref. the Fraunhofer study, CSTEE/98/10-Add. 1), this judgement should be valid.
Risk assessment of dermal exposure Here one has used exposure data from an occupational study where assembly workers came into skin contact with creosoted wood. Exposure to children in contact with creosoted wood has been calculated simply by converting the occupational data on pyrene (a component of Creosote) by relating it to the smaller skin surface area, lower exposure periods and lower body weights. In addition, a direct conversion from pyrene to B(a)P was undertaken under the assumption that exposure to B(a)P was directly proportional to pyrene relative to their concentrations in Creosote. A calculation according to a dermal exposure scenario in children of 20 ng B(a)P/kg bw/day was compared to the Dutch permissible dermal dose limit in children of 1.6 ng/kg B(a)P/kg bw/day based on tumorigenicity data from mice. Since the exposure exceeded the limit, the risk was judged to be unacceptable. Note that there is a miscalculation in this report in that the dermal exposure should be 2 ng BaP/kg bw/day rather than 20 ng BaP/kg bw/day (see point 5, CSTEE/98/10-Add. 4).
The exposure assessment may be overestimated since the exposure is given as amount deposited on the skin, not the amount taken up into the body after dermal absorption. There may be differences in the degree of dermal absorption of Creosote between humans and mice. Further, the exposure assessment may be overestimated since one has assumed that exposure to B(a)P is directly proportional to that of pyrene. On the other hand, the risk assessment is underestimated since it is based upon B(a)P carcinogenicity and not data from the Fraunhofer study with Creosote.
5. Study on the Justification in Scientific Terms of Allowing the Netherlands to retain its National Laws on Creosote in Place of Council Directive 94/60/EEC, CSTEE/98/10-Add. 4 (Grimmer):
This is a review of CSTEE/98/10-Add. 3 with critical comments to the assessments and evaluations therein. In the Appendix 3 of the Dutch foundation of the appeal (CSTEE/98/10-Add.3) there is a miscalculation in the estimation of the daily exposure to BaP. The correct amount should be 0.163 µg rather than 1.63 µg. The correct figure results in a daily dose of 2 ng BaP/kg bw/day. It gives some data on the content of selected PAH in Creosote and presents a table of carcinogenic potencies of various PAH relative to B(a)P. However, it does not specifically give any new exposure data or risk assessments of children exposed to creosoted wood in playgrounds. Therefore, this report will not be further commented upon.
6. Position of the Government of the Federal Republic of Germany, CSTEE/98/10-Add. 5, including CSTEE/98/10-Add. 6 (MAK documentation):
In Germany the designation Creosote is used only for 9 different liquid by-products of the burning of coal or wood. The regulations for these formulations are based on the content of BaP and on contents of water-soluble phenols. If the content of phenols or BaP exceed 3% or 500 ppm, respectively, the production and use are prohibited. Formulations with a BaP content between 50 and 500 ppm may only be used for wood treatment in industrial processes. Sale, including that to private consumers, is only permitted at a BaP content up to 50 ppm. There are also regulations for the use and marketing of treated wood products.
All other tar oil-containing formulations are not allowed for sale to private consumers irrespective of their BaP content. For professional use there are various restrictions. Formulations containing up to 5 ppm BaP may only be used in closed plants. Higher contents are permitted for novel impregnation together with a final vacuum or re-heating. 50 to 500 ppm BaP formulations are permitted for the treatment of railway sleepers and electricity poles. Manufacture, use and marketing of products containing more than 500 ppm is prohibited. Marketing and use of the treated wood products is also regulated.
The more strict regulations of tar oil products have been justified by the classification of BaP and of PAH-containing mixtures as animal carcinogens by the German MAK-Committee (CSTEE/98/10-Add.6), the high carcinogenic potency of the PAH constituents and the limited possibility to quantify the carcinogenic risk of human exposure. Nevertheless a three times per week skin contact of children for 5 years with wood treated with tar oil containing 25% BaP has been estimated to result in a 2% lifetime risk of cancer development. This risk assessment has been based on a dermal carcinogenicity study in mice, which received 50 m l of a solution containing 25 ppm and 50 ppm BaP three times a week. The lower concentration induced tumours in 44%, the higher in 95% of the animals.
7. Karlehagen Epidemiology Study, CSTEE/98/10-Add. 7:
Cancer incidence was studied among 922 creosote-exposed impregnators at 13 plants in Sweden and Norway. The total cancer incidence observed was lower than expected, with 129 cases observed versus 137 expected. The excess of cancer of the lip (5 observed vs. 2.05 expected) is of borderline statistical significance (in Table 1, footnote reports p=0.05 whereas 95 % confidence interval in first line includes unity). The excess of non-melanoma skin cancer was statistically significant, and is biologically plausible, being concentrated in those working 10+ years and being related to a cancer site which has been previously suspected as a target site of the same agent. On the other hand, the potential biases correctly suggested by the authors cannot be ruled out.
8. Evaluation of German Exposure Estimates by ERM (Environmental Resources Management, London), CSTEE/98/10-Add. 8:
The evaluation of the German position regarding exposure and of additional data leads to the conclusion that the German population is not directly exposed to unusually high doses of Creosote through products sold to customers and through contact with Creosote-treated timber, nor is the German aquatic environment exposed to unusually high levels of PAHs coming from Creosote-treated wood.
While little data were available concerning the exposure of German workers to Creosote, it is considered likely that exposure levels are comparable to those in other Member States. It is considered unlikely that German Workers are exposed to unusually high levels of Creosote in comparison to other workers in other Member States.
9. Human Health and Environmental Concerns of Creosote, CSTEE/98/10-Add.9 (Danish Position):
The Danish Authorities describe that Creosote is not approved for use in Denmark, although it has been used for more than a century. About 10,000 tonnes of Creosote is, however, produced in the country and exported to Sweden, Norway and Germany. These products are claimed to contain less than 50 ppm BaP.
A study of Creosote composition in impregnated poles after 40 years of use is described. Substances with the lowest boiling point showed the highest migration and the part of the poles above ground had lost the largest amounts. Creosote components could only be detected in soil in close contact with the pole.
The possibility of ground water contamination is mentioned, but the data on measured concentrations of Creosote components were restricted to contaminated sites.
It is claimed that the Danish climate will decrease the importance of degradation, both photolytic and microbial, as compared to other countries in the EU.
10. Report to the Commission of the European Union by SORGO consultant, CSTEE/98/10-Add. 10 (Position of Denmark):
P. M. Sorgo has evaluated the contribution from the Danish Authorities (CSTEE/98/10-Add. 9). In summary, he found that the Danish population is not exposed to unusually high doses of PAH from the use of Creosote, neither from treated wood or via ground water consumption. These conclusions were, however, based on the present situation when no Creosote is used in the country.
11. Study on the Justification in Scientific Terms of Allowing Sweden to retain its National Laws on Creosote in Place of Council Directive 94/60/EEC, CSTEE/98/10-Add. 11:
This is a very detailed and transparent report of high quality. In contrast to CSTEE/98/10-Add. 3, one has here assessed exposure in children by calculating the amount absorbed into the body based on skin absorption rate data for pyrene from a human coal-tar ointment study. The calculated uptake of B(a)P was 0.85 ng/kg bw/day, and thus substantially lower than the calculated exposure in CSTEE/98/10-Add. 3 (20 ng/kg bw/day). A large part of this difference is due to the fact that here the absorbed dose, and not the dose applied on the skin, was calculated. This report has used a permissible dose of 4.8 ng/kg bw/day (and not 1.6 ng/kg bw/day as in CSTEE/98/10-Add. 3) since the exposure period was set to 2 hours a day for six months (and not 3 hours a day for a whole year). It was judged that the cancer risk to children from direct exposure to Creosote from contact with creosote-treated wood will not be unacceptable (disproportionally high), since the uptake was less than the permissible dose for this scenario.
The exposure assessment scenario involving the private use of creosote-treated wood and treatment of untreated wood with Creosote for construction purposes provided an uptake of B(a)P of 47 ng/kg bw/day. This was correlated to the Dutch permissible daily dose for B(a)P via skin exposure for an adult member of the general public of 2.1 m g/kg bw/day (recalculated with an exposure period of 8 hours per day for two weeks every year). Also this exposure was judged not to be unacceptably (disproportionally) high.
In this case the exposure assessment relies on a number of assumptions, which may or may not hold true (these are clearly presented in the text). In addition, the exposure may be underestimated since the calculations have used mean absorption rates for pyrene, and not maximum values (12 vs 23 pmol/cm²/hr). On the other hand, the exposure assessment may be overestimated since one has assumed that absorption of B(a)P is directly proportional to that of pyrene. In contrast, the risk assessment is underestimated since it is based upon B(a)P carcinogenicity and not data from the Fraunhofer study with Creosote.
12. Conclusion
Creosote is a coal tar product, which contains varying amounts of PAHs and other mutagenic and carcinogenic substances. Coal tar products including Creosote are classified as potential human carcinogens (EU: Category 2, IARC: 2A). This is mainly based on several positive skin painting studies in mice as well as some suggestive epidemiological evidence in humans. Due to the genotoxic potential of PAHs including BaP and other components of coal tar the carcinogenic potential cannot be considered thresholded. As a consequence the carcinogenic risk of exposure is considered linearly dose-dependent so that each exposure is also associated with a certain risk even at low doses.
The carcinogenic potential of coal tar preparations has been reaffirmed by a skin painting study performed by the Fraunhofer Institute. The CSTEE concludes that this is a well-designed study which clearly indicates a linear dose response relation to the BaP content of the administered substances. Both preparations (CPT1 and CPT2) have a five-fold higher potency to induce skin tumours than BaP, presumably due to the presence of other substances than BaP in Creosote. It can be inferred from the Fraunhofer study that Creosote containing 50 ppm BaP would induce a significant incidence of skin cancer in mice.
Data to fully evaluate the relevance of effects seen in a mouse skin painting study for human exposure situations are insufficient. Species dependent sensitivity of dermal exposure to the carcinogenic actions of Creosote will be affected by morphology and physiology of the skin, by metabolic activation and inactivation in the skin and by repair processes. Moreover the precision of the human exposure estimates presented in the different reports is debatable. On the basis of the available information, a scientifically justified assessment of carcinogenic risk e.g. for the dermal exposure of children playing on wood treated with Creosote is therefore difficult.
Exposure of children from dermal contact with creosote-treated wood has been estimated from either occupational studies of pyrene or a coal-tar ointment study, and recalculated with respect to BaP. These two estimates are fairly similar (2 vs 0.85 ng BaP/kg bw/day). The CSTEE concludes that these estimates are quite uncertain, but that they give an indication of the possible dimension of the actual exposure. Annual intakes of BaP from food has been estimated to be in the order of 0.3 - 1.6 mg (Fritz) 1971; Jacob and Grimmer 1996; Santodonato et al. 1979; Strubelt 1986). This would result in daily exposures of 12 - 63 ng/kg bw for a person weighing 70 kg.
Extrapolating skin carcinogenicity data from mice to the human situation also entails a number of uncertainties leading to difficulties in directly using cancer potency data from mice to assess cancer risk in humans. However, based on linear extrapolation of the potency of Creosote revealed in the Fraunhofer study, the lifetime risk from the calculated exposure estimates of approximately 1 ng BaP/kg bw/day would be in the order of 10 -4. Such a risk level gives clear reason for concern.
The Scientific Committee of Toxicity, Ecotoxicity and the Environment concludes the following:
1. Given the genotoxicity of BaP and the outcome of the Fraunhofer skin painting study, there is sufficient scientific evidence to support the opinion that there is a cancer risk to consumers from Creosote containing less than 50 ppm BaP and/or from wood treated with such Creosote.
BaP is a good indicator for the carcinogenic hazard of the Creosote preparation tested, since there was a linear relationship between cancer incidence and BaP dose. However, the cancer potency of the Creosote preparation was 5-fold higher than judged from its BaP content.
2. On the basis of the available information, even taking into account the considerable uncertainties in assessing the risks for children coming into contact with Creosote-treated wood, the magnitude of the risk gives clear reasons for concern. However, the highest estimated exposure is some 6-30 times lower than the oral exposure of the adult population to BaP in food.
In order to get a better estimate of the exposure situation, one would have to perform a real-life, mass-balance study in exposed children. In addition to being very complicated and resource intensive, to conduct such a study would raise ethical questions.
Annex
List of documents made available to the Scientific Committee on Toxicity, Ecotoxicity and the Environment via its Secretariat to help it reach the opinion requested by the services of the Commission on the subject:
'Cancer risk to consumers from Creosote containing less than 50 ppm benzo-[a]-pyrene and/or from wood treated with such Creosote and estimation of respective magnitude'
CSTEE/98/10
Hazardous properties of Creosote.
Note from Mr. P. Ortùn (Director III/C) to Mr. B. Carsin (Director XXIV/B) dated 20/3/98 - Ref. 005846.
CSTEE/98/10 - Add. 1
Dermal Carcinogenicity Study of two Coal Tar Products (CTP) by Chronic Epicutaneous Application in Male CD-1 Mice (78 weeks)
Final report made by the Fraunhofer Institute of Toxicology and Aerosol Research (Hannover).
CSTEE/98/10 - Add. 2
An Evaluation of the Carcinogenicity of Coal-Tar derived Creosote
Submitted by the International Tar Association (UK) - 29/12/1997.
CSTEE/98/10 - Add. 3
Foundation of the appeal against the EC-directive on creosote
Made by bkh consulting engineers on request of the Dutch Ministry of Housing, Spatial Planning and Environment - Delft (NL) 11/7/1995.
CSTEE/98/10 - Add. 4
Study on the Justification in Scientific Terms of Allowing the Netherlands to retain its National Laws on Creosote in Place of Council Directive 94/60/EEC
Made by Prof. Dr.G. Grimmer(Biochemisches Institüt für Umweltcarcinogene - Germany) on request of the European Commission (contract no. ETD/95/84066).
CSTEE/98/10 - Add. 5
Report of the Government of the Federal Republic of Germany of 19 June 1995 concerning Directive 94/60/EC of the EP and of the Council of 20/12/94 on the 14 th amendment to Directive 76/769/EEC for alignment of the legal and administrative regulations of the Member States for restricting the marketing and use of certain hazardous substances and formulations (OJ No. L 365 of 31/12/94, p. 1).
Submitted by the German Authorities in support of their request under Art. 100a (4).
CSTEE/98/10 - Add. 6
A report from theGerman MAK Commission on the suitability of Benzo[a]pyrene as a marker substance "Polycyclische Aromatische Kohlenwasserstoffe, krebserzeugende (PAH)" and its translation into English "Polycyclic aromatic hydrocarbons, carcinogenic (PAH)".
CSTEE/98/10 - Add. 7
Cancer incidence among creosote-exposed workers
From the Scand. J. Work Environ. Health - 1992.
CSTEE/98/10 - Add. 8
Study on the Scientific Evaluation of the German Request for a Derogation from the Provisions of Council Directive 94/60/EC concerning creosote (April 1996).
Made by ERM Consultants on request of the European Commission (contract no. ETD/95/84081).
CSTEE/98/10 - Add. 9
A report "Human Health and Environmental Concerns of Creosote" (5/12/1995)
Submitted by the Danish Authorities in support of their request under Art. 100a (4) - 5/12/1995.
CSTEE/98/10 - Add. 10
Study on the Justification in Scientific Terms of Allowing Danmark to retain its National Laws on Creosote in Place of Council Directive 94/60/EEC
Made by Dr. Sorgo (Consultant) on request of the European Commission (contract no. ETD/96/84094) - 20/11/1996 - and an additional letter from Dr. Sorgo.
CSTEE/98/10 - Add. 11
Study on the Justification in Scientific Terms of Allowing Sweden to retain its National Laws on Creosote in Place of Council Directive 94/60/EEC
Made by WS ATKINS Consultants on request of the European Commission (contract no. ETD/96/500069) - August 1997.
CSTEE/98/10 - Add. 12
Creosote - draft outline report for CSTEE information
CSTEE/98/10 - Add. 13
Evaluation of a Dermal Carcinogenicity Study with Mice with Two Different Creosotes.
Report from Fraunhofer-Institute of Toxicology and Aerosol Research (Hannover) - May 1998.
Document transmitted by Mr. P. Buigues (DG III).
CSTEE/98/10 - Add. 14
T25: A Simplified Carcinogenic Potency Index: Description of the System and Study of Correlations between Carcinogenic Potency and Species/Site Specificity and Mutagenicity.
Report from E. Dybing - January 1997.
CSTEE/98/10 - Add. 15
Potency considerations regarding Creosote.
Report from Prof. Jansson - 4/8/1998.
CSTEE/98/10 - Add. 16
Creosote - Comments from Erik Dybing.
Report from E. Dybing - 31/8/1998.
CSTEE/98/10 - Add. 17
Fritz, W. (1971) Umfang und Quellen der Kontamination unserer Lebensmittel mit krebserzeugenden Kohlenwasserstoffen, Ernähruungsforsch, XVI, 4, 547-557.
CSTEE/98/10 - Add. 18
Jacob, J. und Grimmer, G. (1996) Metabolism and excretion of polycyclic aromatic hydrocarbons in rat and in human. Centr. Eur. J. publ. Hlth 4, Suppl. p. 33-39.
CSTEE/98/10 - Add. 19
Santodonato, J., Basu, D. und Howard, P.H. (1979) Multimedia human exposure and carcinogenic risk assessment for environmental PAH, Polynuclear Aromatic Hydrocarbons, Chemistry and Biological Effects. Bjorseth, A. and Dennis A. J. (Eds.), Battelle Press, Columbus, Ohio, 435-454.
CSTEE/98/10 - Add. 20
Strubelt, O. (1986) Über das Viorkommem und die Bedeutung von Karzinogen in der menschlichen Umwelt. Dt. Apoth. Z. 126, 1977.
