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Endpoint:
adsorption / desorption, other
Remarks:
adsorption /desorption of single PAH
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Studies based on accepted scientific methods, peer-reviewed data
Principles of method if other than guideline:
Determination of (log) Koc values from (log) Pow data of single polycyclic aromatic hydrocarbons using (Q)SAR calculations; no (log) Koc for anthracene oil as such is derivable due to the complex composition (UVCB).
GLP compliance:
no
Type of method:
other: (Q)SAR calculation
Remarks:
experimentally determined log Pow values for individual PAH were converted to log Koc values by the relation (equation) of Karickhoff (1979)
Media:
soil
Specific details on test material used for the study:
The following polycyclic aromatioc hydrocarbons are taken into account in the determination of the range of (log) Koc values. These are representative for the UVCB substance anthracene oil.

- Acenaphthene
- Fluorene
- Phenanthrene
- Anthracene
- Fluoranthene
- Pyrene
Test temperature:
not applicable
Details on study design: HPLC method:
not applicable
Details on sampling:
not applicable
Details on matrix:
not applicable
Details on test conditions:
not applicable
Computational methods:
not applicable
Key result
Type:
Koc
Value:
ca. 5 000 - ca. 100 000 dimensionless
Remarks on result:
other: range for 6 PAH from acenaphthene to pyrene; calculated values: log Koc ranging from 3.71 to 5.01
Key result
Type:
Koc
Value:
ca. 5 130 dimensionless
Remarks on result:
other: substance acenaphthene; calculated value: log Koc = 3.71
Key result
Type:
Koc
Value:
ca. 9 330 dimensionless
Remarks on result:
other: substance fluorene; calculated value: log Koc = 3.97
Key result
Type:
Koc
Value:
ca. 22 900 dimensionless
Remarks on result:
other: substance phenanthrene; calculated value: log Koc = 4.36
Key result
Type:
Koc
Value:
ca. 21 380 dimensionless
Remarks on result:
other: substance anthracene; calculated value: log Koc = 4.33
Key result
Type:
Koc
Value:
ca. 102 330 dimensionless
Remarks on result:
other: substance fluoranthene; calculated value: log Koc = 5.01
Key result
Type:
Koc
Value:
ca. 93 330 dimensionless
Remarks on result:
other: substance pyrene; calculated value: log Koc = 4.97
Details on results (HPLC method):
not applicable
Adsorption and desorption constants:
not applicable
Recovery of test material:
not applicable
Concentration of test substance at end of adsorption equilibration period:
not applicable
Concentration of test substance at end of desorption equilibration period:
not applicable
Transformation products:
not measured
Details on results (Batch equilibrium method):
not applicable
Statistics:
--

Several methods are available for deriving log Koc (Koc) values from log Pow (Kow) data using (Q)SAR calculations. Two methods have been selected from European Competent Authorities2) 3)in the process of risk assessment of complex substances (UVCB) in order to obtain log Koc values from log Kow data. In both cases, main components of the substances were polycyclic aromatic hydrocarbons similar to PAH present in anthracene oil. (Log) Koc values of relevant PAH will be used to characterise the absorption behaviour of anthracene oil to organic matter. Log Koc values derived with the equation of Karickhoff are higher by 0.25 log Koc units than the values calculated with the equation of Seth. The substance set used by Karickhoff for the derivation of his equation comprised mostly non-halogenated aromatic hydrocarbons. Therefore, this relation is used to calculate the log Koc values for the constituents of anthracene oil. Log Koc values of anthracene oil constituents are derived based on log Pow data determined by Miller et al. 1985 and the relation of Karickhoff (see table below, third and fourth column). Data of EU 2008 and KEMI 2010 can be used for comparison.

 

Overview of estimated log Koc values, derived from log Pow (Kow) values (main constituents of anthracene oil)

 

 

CAS-No.

Log Kow (exp.)1)(25 °C)

Log Koc
(according toKarickhoff/ Seth)

 

Log Pow
(EU 20082))

Log Koce)
(EU 20082))

Log Powf)
(KEMI 20103))

Log Kocg)
(KEMI 20103))

Acenaphthene

83-32-9

3.92a)

3.71/ 3.46

4.00c)

3.79

4.02

3.56

Fluorene

86-73-7

4.18a)

3.97/ 3.72

4.22c)

4.01

4.13

3.67

Phenanthrene

85-01-8

4.57a)

4.36/ 4.11

4.57b)

4.36

4.50

4.05

Anthracene

120-12-7

4.54a)

4.33/ 4.08

4.68b)

4.47

4.50

4.05

Fluoranthene

206-44-0

5.22d)

5.01/ 4.76

5.20b)

4.99

5.06

4.60

Pyrene

129-00-0

5.18a)

4.97/ 4.72

4.98c)

4.77

4.99

4.56

 

a) column elution method

b) slow stirring method (average value)

c) shake flask method

d) calculated

e) compare to EU RAR 2008: Koc values were estimated using the experimental equation derived by Karickhoff et al. (1979)4): Koc = 0.63 Kow (or log Koc = 1.00 log Kow – 0.21)

f) Log Pow values are means of the range of log Kow values reported by Mackay et al. 2006

g) compare to KEMI 2010: Koc values were estimated using the equation derived by Seth et al. 1999)5): Koc = 0.35 Kow;

The error limits on Koc, resulting from differences in the nature of organic matter and the experimental difficulties and constraints in Koc measurements, are a factor of 2.5 in both directions, i.e. the coefficient 0.35 may vary from 0.14 to 0.88.

 

References:

1)    Miller MM, Wasik P, Huang G-L, Shiu W-Y, and Mackay D (1985): Relationships between octanol-water partition coefficient and aqueous solubility. Environ. Sci. Technol. 19, 522-529

2)    EU (2008): Coal-Tar Pitch, high temperature - European Union Risk Assessment Report, The Netherlands (URL:https://echa.europa.eu/documents/10162/433ccfe1-f9a5-4420-9dae-bb316f898fe1)

3)    KEMI (2010): Creosote (PT8) - Document II-A - Risk Assessment (Final). Kemikalieinspektionen, Swedish Chemicals Agency

4)    Karickhoff SW, Brown DS, and Scott TA (1979): Sorption of hydrophobic pollutants on natural sediments. Water Res. 13, 241-248 Karickhoff SW (1981): Semi-empirical estimation of sorption of hydrophobic pollutants on natural sediments and soil. Chemosphere 10, 883-846

5)    Seth R, Mackay D, and Muncke J (1999): Estimating the organic carbon partition coefficient and its variability for hydrophobic chemicals. Environ. Sci. Technol. 33, 2390-239

6)    Mackay (2006)

Endpoint:
adsorption / desorption: screening
Remarks:
adsorption / desorption of single PAH
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The source test materials are individual polycyclic aromatic hydrocarbons. For read-across to the target substance anthracene oil, PAH composed of three to four fused rings are selected. Depending on size/molecular weight and structure, physico-chemical and environmental properties will be different. The target substance anthracene oil (benzo[a]pyrene < 50 ppm, AOL) is composed of a broad range of PAH consisting of two to four aromatic rings similar to the source materials.
The potential of anthracene oil for absorption / desorption to/from organic matter will be characterised by the range of PAH that constitute its composition. The source substances selected are main constituents of anthracene oil. Therefore, results obtained for Koc values of these compounds can be used in order to characterise the absorption / desorption potential of anthracene oil itself.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source test materials are individual PAH. Results are obtained by (Q)SAR calculations based on reliable measured log Kow values of selected PAH using methods also applied by competent national authorities of EU states in the process of review and evaluation of submitted data. Results are reported for individual substances and considered valid for the effects specified.
The target material anthracene oil is a UVCB substance produced by the distillation of coal tars extracting the approximate distillation range from ca. 300 °C to 400 °C. This distillation range excludes mostly low molecular aromatic hydrocarbons (especially one-ring and to a lower extent two-ring aromatics) as well as polycyclic aromatic hydrocarbons composed of more than four to five rings depending on the respective boiling points of the individual aromatic substances. Major constituents are three-ring (ca. 45 %) and four-ring (ca. 10 %) aromatics from acenaphthene to pyrene. Phenanthrene is the major constituent amounting to about 25 - 31 % (typical concentration).

3. ANALOGUE APPROACH JUSTIFICATION
Properties of the target substance anthracene oil relevant for environmental distribution will be determined by the properties of the PAH that are constituents of anthracene oil. Under environmental conditions or during processing of the target substance, environmentally available or volatile/water soluble components of anthracene oil can be released. These will be PAH (see above). Distribution properties (absorption/desorption) of these PAH will be specific for the environmental behaviour of anthracene oil. Therefore, it is justified to use date determined for individual PAH that are constituents of anthracene oil to characterise the environmental properties (Koc values) of anthracene oil itself.
Reason / purpose for cross-reference:
read-across source
Principles of method if other than guideline:
Read-across to preceding entry:
Source test material: polycyclic aromatic hydrocarbons (PAH), generic mixture;
Reference: EU 2008 (Rapporteur: The Netherlands), KEMI 2010 (Kemikalieinspektionen, Swedish Chemicals Agency)
Key result
Type:
Koc
Value:
ca. 5 000 - ca. 100 000 dimensionless
Remarks on result:
other: range for 6 PAH from acenaphthene to pyrene; calculated values: log Koc ranging from 3.71 to 5.01
Remarks:
the test results of the source substance are adopted as weight of evidence for the target substance anthracene oil
Key result
Type:
Koc
Value:
ca. 5 130 dimensionless
Remarks on result:
other: substance acenaphthene; calculated value: log Koc = 3.71
Remarks:
the test result of the source substance is adopted as weight of evidence for the target substance anthracene oil
Key result
Type:
Koc
Value:
ca. 9 330 dimensionless
Remarks on result:
other: substance fluorene; calculated value: log Koc = 3.97
Remarks:
the test result of the source substance is adopted as weight of evidence for the target substance anthracene oil
Key result
Type:
Koc
Value:
ca. 22 900 dimensionless
Remarks on result:
other: substance phenanthrene; calculated value: log Koc = 4.36
Remarks:
the test result of the source substance is adopted as weight of evidence for the target substance anthracene oil
Key result
Type:
Koc
Value:
ca. 21 380 dimensionless
Remarks on result:
other: substance anthracene; calculated value: log Koc = 4.33
Remarks:
the test result of the source substance is adopted as weight of evidence for the target substance anthracene oil
Key result
Type:
Koc
Value:
ca. 102 330 dimensionless
Remarks on result:
other: substance fluoranthene; calculated value: log Koc = 5.01
Remarks:
the test result of the source substance is adopted as weight of evidence for the target substance anthracene oil
Key result
Type:
Koc
Value:
ca. 93 330 dimensionless
Remarks on result:
other: substance pyrene; calculated value: log Koc = 4.97
Remarks:
the test result of the source substance is adopted as weight of evidence for the target substance anthracene oil
Endpoint:
adsorption / desorption, other
Remarks:
Measurements of PAH distribution between particulate matter and gas phase in the atmosphere
Type of information:
experimental study
Remarks:
Compilation of different experimental studies
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Remarks:
peer-reviewed data, acceptable for assessment
Principles of method if other than guideline:
Determination of PAH in the gas and particle phase of ambient air
GLP compliance:
no
Type of method:
other: atmospheric monitoring
Media:
other: particle and gas phase
Specific details on test material used for the study:
Distribution between the gas and partical phase in the atmosphere was determind and is reported for the 16 EPA PAH. The following PAH are representative for the UVCB substance anthracene oil.
- Acenaphthene
- Fluorene
- Anthracene
- Phenanthrene
- Fluoranthene
- Pyrene
Radiolabelling:
no
Test temperature:
ambient temperature
Details on study design: HPLC method:
not applicable
Analytical monitoring:
yes
Details on sampling:
air sampling (ambient atmosphere at different locations)
Details on matrix:
gas phase and air particles were collected at different locations
Details on test conditions:
no applicable
Computational methods:
not applicable
Key result
Phase system:
other: particles in ambient atmosphere
Type:
other: classification of PAH regarding partitioning between particulates and gas phase in the atmosphere
Remarks on result:
other: as a first approximation, PAH with a liquid-phase vapour pressure (PL) of <10E-5 Pa at ambient temperature are present in the particle phase, and those with values of PL >10E-2 Pa are in the gas phase
Key result
Phase system:
other: particles in ambient atmosphere
Type:
other: general classification of PAH
Remarks on result:
other: naphthalene to phenanthrene are “gas-phase” aromatics (2- and 3-ring aromatics), while the PAH from benzofluoranthenes (5 rings) to the high-molecular mass PAH are “particle-phase” aromatics. The medium range of the 4-ring PAH show intermediate behaviour
Key result
Phase system:
other: particles in ambient atmosphere
Type:
other: classification of anthracene oil constituents (PAH)
Remarks on result:
other: three-ring PAH (acenaphthene to phenanthrene) will predominantly be present in the gas phase of the atmosphere, while four ring PAH (fluoranthene, pyrene) will be distributed between gas and particulate phase
Details on results (HPLC method):
not applicable
Adsorption and desorption constants:
no constants given (see below)
Recovery of test material:
not applicable
Concentration of test substance at end of adsorption equilibration period:
not applicable
Concentration of test substance at end of desorption equilibration period:
not applicable
Transformation products:
not measured
Details on results (Batch equilibrium method):
not applicable
Statistics:
not applicable

Excerpt from

ANNEX XV TRANSITIONAL DOSSIER - CTPHT CAS 65996-93-2, SECTION B. INFORMATION ON HAZARD AND RISK, B.4.1.1 Atmospheric degradation (or fate in the atmosphere)

. . . In the atmosphere PAHs are partitioned between the gas and particle phases, with the gas-particle partitioning depending on a number of factors, including the liquid-phase (or sub-cooled liquid-phase) vapour pressure of the PAH at the ambient atmospheric temperature, the surface area of the particles per unit volume of air, and the nature of the particle (Wania & Mackay, 1996; Pankow, 1987; Bidleman, 1988). As a first approximation, chemical compounds with liquid-phase vapour pressure of PL< 10-5 Pa at the ambient atmospheric temperature are present in the particle phase, and those with values of PL> 10-2 Pa at the ambient atmospheric temperature are essentially totally in the gas phase (Arey & Atkinson, 2003). As shown in measurements performed in Norway (Oslo), Germany (Bayreuth) and California, USA (Torrance), the 2- to 4-ring PAHs with vapour pressures ≥ 10-4 Pa are largely gas-phase species, whereas PAHs with 4 rings or more, with vapour pressure < 10-4 Pa are particle-associated (see Table B.4.1).

TableB.4.1.    Summary of gas-particle phase partitioning

(PAH in bold = selected components of anthracene oil < 50 ppm BaP)

PAH (number of rings)

Vapour pressure (Pa)a)

Observed % in particulate phase

Naphthalene (2)

1.1·101

0b)

0e)

Acenaphthylene (3)

1.3·10-1

Acenaphthene (3)

4.0·10-1

Fluorene (3)

1.1·10-1

0b)

Anthracene (3)

8.7·10-4

3b)

0.5e)

Phenanthrene (3)

2.0·10-2

3b)

12.4c)

1.9d)

0.4e)

Fluoranthene (4)

6.0·10-3

54b)

49.7c)

19.1d)

5.9e)

Pyrene (4)

4.4·10-4

57b)

61.4c)

29.6d)

7.5e)

Benz(a)anthracene (4)

2.1·10-6

97b)

89.4c)

62.7d)

Chrysene (4)

1.4·10-6

99b)

Benzo(b)fluoranthene(5)

1.0·10-6

100b)

92.2c)

92.3d)

Benzo(a)pyrene (5)

5.3·10-8

100b)

100c)

100d)

98.3e)

Perylene (5)

1.8·10-8

100b)

90.0e)

Dibenzo[a,c]anthracene (5)

5.7·10-9

100b)

Dibenzo(a,h)anthracene (5)

4.9·10-9

100b)

100c)

100d)

Benzo(ghi)perylene (6)

1.0·10-8

100b)

100c)

100d)

Summary as given in EC (2001b).a)Vapour pressures taken from Neiderfellner et al.(1997) and Oja & Suuberg (1998);

b)Measurements made in Oslo, January/February 1979 (Thrane & Mikalsen, 1981);

c)Annual mean measurements made in Bayreuth, Germany, May 1995-April 1996 (Horstmann & McLachlan, 1998);

d)Summer mean measurements made in Bayreuth, Germany, May-October 1995 (Horstmann & McLachlan, 1998);

e)Measurements made in Torrance, California, February 1986 (Arey et al., 1987).

References:

  • Arey J, Zielinska B, Atkinson R, Winer AM (1987) Polycyclic aromatic hydrocarbon and nitroarene concentrations in ambient air during a winter-time high NOX episode in the Los Angeles basin. Atmosph Environ 21: 1437-1444.
  • Bidleman, TF (1988) Atmospheric processes. Environ Sci Technol 22: 361-367.
  • EC (2001b) Ambient Air Pollution by Polycyclic Aromatic Hydrocarbons (PAH). Position Paper. Prepared by the Working Group on Polycyclic Aromatic Hydrocarbons. July, 2001.
  • Horstmann M, McLachlan MS (1998) Atmospheric deposition of semivolatile organic compounds to two forest canopies. Atmos Environ 32: 1799-1809.
  • Neiderfellner J, Lenoir D, Matuschek G, Rehfeldt F, Utschick H, Bruggeman R (1997) Description of vapour pressures of polycyclic aromatic hydrocarbons by graph theoretical indices. Quant Struct-Act Relat 16: 38-48.
  • Oja V, Suuberg EM (1998) Vapor pressures and enthalpies of sublimation of polycyclic aromatic hydrocarbons and their derivatives. J Chem Eng Data 43: 486-492.
  • Pankow JF (1987) Review and comparative analysis of the theories on portioning between the gas and aerosol particulate phases in the atmosphere. Atmos Environ 21: 2275-2283.
  • Thrane KE, Mikalsen A (1981) High-volume sampling of airborne polycyclic aromatic hydrocarbons using glass fibre filters and polyurethane foam. Atmos Environ 15: 909-918.
  • Wania F, Mackay D (1996) Tracking the distribution of persistent organic pollutants. Environ Sci Technol 30: 390-396.
Validity criteria fulfilled:
not applicable
Endpoint:
adsorption / desorption, other
Remarks:
Measurements of PAH distribution between particulate matter and gas phase in the atmosphere
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The source test materials are individual polycyclic aromatic hydrocarbons. For read-across to the target substance anthracene oil, PAH composed of three to four fused rings are selected. Depending on size/molecular weight and structure, physico-chemical and environmental properties will be different. The target substance anthracene oil (benzo[a]pyrene < 50 ppm, AOL) is composed of a broad range of PAH consisting of two to four aromatic rings similar to the source materials.
The potential of anthracene oil for absorption to air particulates will be characterised by the range of PAH that constitute its composition. The source substances selected are main constituents of anthracene oil. Therefore, results obtained for the distribution between air particulates and atmospheric air of these compounds can be used in order to characterise the distribution in air of anthracene oil itself.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
Source test materials are individual PAH. Results are obtained by analytical measurements of air samples and are reported for individual well defined substances. Results have been evaluated in an expert review. Substances with similar properties are allocated to groups and specific properties are related to the test materials.
The target material anthracene oil is a UVCB substance produced by the distillation of coal tars extracting the approximate distillation range from ca. 300 °C to 400 °C. This distillation range excludes mostly low molecular aromatic hydrocarbons (especially one-ring and to a lower extent two-ring aromatics) as well as polycyclic aromatic hydrocarbons composed of more than four to five rings depending on the respective boiling points of the individual aromatic substances. Major constituents are three-ring (ca. 45 %) and four-ring (ca. 10 %) aromatics from acenaphthene to pyrene. Phenanthrene is the major constituent amounting to about 25 - 31 % (typical concentration).

3. ANALOGUE APPROACH JUSTIFICATION
Properties of the target substance anthracene oil relevant for environmental distribution will be determined by the properties of the PAH that are constituents of anthracene oil. Under environmental conditions or during processing of the target substance, environmentally available or volatile components of anthracene oil can be released. These will be PAH (see above). Distribution properties (distribution in ambient atmosphere between particles and air) of these PAH will be specific for the environmental behaviour of anthracene oil. Therefore, it is justified to use date determined for individual PAH that are constituents of anthracene oil to characterise the environmental properties (distribution between atmospheric air and air particulates) of anthracene oil itself.
Reason / purpose for cross-reference:
read-across source
Principles of method if other than guideline:
Read-across to preceding entry:
Source test material: polycyclic aromatic hydrocarbons (PAH), generic mixture;
Reference: EU 2008 (Rapporteur: The Netherlands)
Key result
Phase system:
other: particles in ambient atmosphere
Type:
other: classification of PAH regarding partitioning between particulates and gas phase in the atmosphere
Remarks on result:
other: as a first approximation, PAH with a liquid-phase vapour pressure (PL) of <10E-5 Pa at ambient temperature are present in the particle phase, and those with values of PL >10E-2 Pa are in the gas phase
Remarks:
the test results of the source substance are adopted as weight of evidence for the target substance anthracene oil
Key result
Phase system:
other: particles in ambient atmosphere
Type:
other: general classification of PAH
Remarks on result:
other: naphthalene to phenanthrene are “gas-phase” aromatics (2- and 3-ring aromatics), while the PAH from benzofluoranthenes (5 rings) to the high-molecular mass PAH are “particle-phase” aromatics. The medium range of the 4-ring PAH show intermediate behaviour
Remarks:
the test results of the source substance are adopted as weight of evidence for the target substance anthracene oil
Key result
Phase system:
other: particles in ambient atmosphere
Type:
other: classification of anthracene oil constituents (PAH)
Remarks on result:
other: 3-ring PAH (acenaphthene to phenanthrene) will predominantly be present in the gas phase of the atmosphere, while 4-ring PAH (fluoranthene, pyrene) will be distributed between gas and particulate phase
Remarks:
the test results of the source substance are adopted as weight of evidence for the target substance anthracene oil

Description of key information

The range of Koc values for key components in anthracene oil is estimated to be between approx. 5000 and 100,000 (log Koc between approx. 3.71 and 5.01). Log Koc for anthracene oil is calculated as mean of the six major components (typical concentration above 3 %). This mean value (log Koc = 4.392) relates to a Koc of 24,660.

Key value for chemical safety assessment

Koc at 20 °C:
24 660

Additional information

Adsorption Coefficient

Due to the complex composition of anthracene oil a single Koc value cannot be determined for the substance. Main components (all PAH) will have their individual Koc values. An overview is presented in the following text.

Koc values of PAH have been estimated by calculations based on Pow/log Pow values using different relations between log Pow/Pow and log Koc/Koc. Well established is the equation by Karickhoff et al. (1979) derived from experimental data: log Koc = log Pow - 0.21 (or Koc = 0.63 Kow). Log Koc/Koc data reported for anthracene oil constituents will originate from this equation. Koc data derived using this equation have also been used in the EU Risk Assessment Report for Coal-tar pitch, high temperature (EU 2008).

Overall properties of anthracene oil will best be represented by the range of log Koc/Koc values corresponding to the PAH present in anthracene oil (acenaphthene to pyrene, see Chapter 1.). The estimated adsorption coefficients for these constituents extend from approx. log Koc ca. 3.71 for acenaphthene to approx. 5.01 for fluoranthene (Koc range from ca. 5100 to 100,000).

Substances with typical concentration above 3 % in anthracene oil are acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene and pyrene with phenanthrene being the major constituent amounting to about 25 - 30 % (typical concentration). Fluorene and fluoranthene are present at a concentration of approx. 7 % each, while acenaphthene and pyrene contribute ca. 4 and 3 % to the total of anthracene oil.

Taking into account the log Koc values of these six substances, a mean log Koc value for anthracene oil can be calculated. Log Koc values are used, because adsorption coefficients were estimated using the log values. The mean log Koc value is calculated to be 4.392 for the six main components of anthracene oil. This value is close to the log Koc values of phenanthrene (4.36) that is selected as marker substance for anthracene oil due to its environmental properties that represent well anthracene oil itself. The Koc is calculated to be 24,660. This value is considered to represent best the properties of anthracene oil by a single Koc value as required for risk assessment.

Adsorption to Soil

Depending on their log Koc, adsorption of individual anthracene oil components to soil organic matter will differ. Lower molecular mass PAH (three-ring aromatics) tend to distribute to water to some extent, but with higher amounts bound to solid matter (higher percentage in soil than in sediment). Higher molecular mass PAH like fluorene and pyrene (four-ring PAH) tend to accumulate even more in the solid phase, while at the same time percentage is shifted from soil more to sediment.

Adsorption to Air Particles

Based on vapour pressure, the more volatile constituents of anthracene oil (three-ring aromatic compounds) are expected in the gas phase of the atmosphere rather than bound to air particulates. The four-ring PAH will absorb to some extent to air particulates and will be distributed between air and airborne particles.