Ethylcyclohexane

Bioaccumulation: aquatic / sediment

Administrative data

Endpoint:

bioaccumulation in aquatic species: fish

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2018

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

accepted calculation method

Justification for type of information:

The bioconcentration factor (BCF) of ethylcyclohexane was calculated by the EPI (Estimation Programs Interface) Suite™, a Windows®-based suite of physical/chemical property and environmental fate estimation programs developed by the EPA’s Office of Pollution Prevention Toxics and Syracuse Research Corporation (SRC).The included program BCFBAF estimates the BCF of an organic compound using the compound's log Kow. Substances are classified either as ionic or non-ionic and are divided into 3 classes of log Kow ranges:log Kow <1,log Kow 1 - 7, log Kow > 7. For each range a best-fit refgression was performed using a training dataset. The BCF of substances with log Kow can be described as:log BCF = 0.6598 log Kow + Σ correction factors. The correction factors are based on specific structural features.In addition the bioconcentration factor BCF and the bioaccumulation factor BAF are estimated using the Arnot-Gobas estimation methology. The model consists of the development of a bioaccumulation model, the parameterisation of the model to reflect Canadian conditions and the calibration of the model to a large BCF and BAF database.The model gives a prediction for non-ionic organic chemicals in three general trophic fish levels (lower, middle, upper) in temperate environments and includes mechanistic processes for bioconcentration and bioaccumulation (e.g uptake/elimination at the gill surface, fecal egestion). The model requires the log Kow and the biotransformation rate constant (k,mn/day) as input parameters.The BAF calculations are derived from large datasets of measured BCF's (Great Lakes).The model is calibrated to each trophic level of measured BAF values thus providing estimates that are in general agreement with measured BAFs, thus capturing the overall food web biomagnification potential of chemicals in aquatic food webs for screening assessments.

Data source

Reference

Reference Type:

other: Software program

Title:

US EPA. [2012]. Estimation Programs Interface Suite™ for Microsoft® Windows, v 4.11]. United States Environmental Protection Agency, Washington, DC, USA.

Author:

United States Environmental Protection Agency, Washington, DC, USA.

Year:

2012

Bibliographic source:

http://www.epa.gov/opptintr/exposure/pubs/episuite.htm

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Guidance on information requirements and chemical safety assessment, Chapter R.6: QSARs and grouping of chemicals, ECHA, May 2008

Deviations:

not applicable

Principles of method if other than guideline:

The bioconcentration factor (BCF) of ethylcyclohexane was calculated by the EPI (Estimation Programs Interface) Suite™, a Windows®-based suite of physical/chemical property and environmental fate estimation programs developed by the EPA’s Office of Pollution Prevention Toxics and Syracuse Research Corporation (SRC).The included program BCFBAF estimates the BCF of an organic compound using the compound's log Kow. Substances are classified either as ionic or non-ionic and are divided into 3 classes of log Kow ranges:log Kow <1,log Kow 1 - 7, log Kow > 7. For each range a best-fit refgression was performed using a training dataset. The BCF of substances with log Kow can be described as:log BCF = 0.6598 log Kow + Σ correction factors. The correction factors are based on specific structural features.In addition the bioconcentration factor BCF and the bioaccumulation factor BAF are estimated using the Arnot-Gobas estimation methology. The model consists of the development of a bioaccumulation model, the parameterisation of the model to reflect Canadian conditions and the calibration of the model to a large BCF and BAF database.The model gives a prediction for non-ionic organic chemicals in three general trophic fish levels (lower, middle, upper) in temperate environments and includes mechanistic processes for bioconcentration and bioaccumulation (e.g uptake/elimination at the gill surface, fecal egestion). The model requires the log Kow and the biotransformation rate constant (k,mn/day) as input parameters.The BAF calculations are derived from large datasets of measured BCF's (Great Lakes).The model is calibrated to each trophic level of measured BAF values thus providing estimates that are in general agreement with measured BAFs, thus capturing the overall food web biomagnification potential of chemicals in aquatic food webs for screening assessments.
Applicability domain of the model (as given in the EPI SUITE User's Guide):
Currently there is no universally accepted definition of model domain.
Following minimum and maximum values for molecular weight and Kow values are given:
Molecular Weight:
Minimum MW: 68.08 (Furan)
Maximum MW: 991.80 Ionic: (2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-3,6-
bis[[4-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]azo]-, tetrasodium salt)
Maximum MW: 959.17 Non-Ionic: (Benzene, 1,1 -oxybis[2,3,4,5,6-pentabromo-)
Average MW: 244.00
Log Kow:
Minimum LogKow: -6.50 Ionic: (2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-3,6-bis[[4-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]azo]-, tetrasodium salt)
Minimum LogKow: -1.37 Non-Ionic: (1,3,5-Triazine-2,4,6-triamine)
Maximum LogKow: 11.26 (Benzenamine, ar-octyl-N-(octylphenyl)-)
3. Adequacy of prediction
The substance ethylcyclohexane falls within the applicability domain described above and, therefore, the predicted value can be considered reliable.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

Ethylcyclohexane

EC Number:

216-835-0

EC Name:

Ethylcyclohexane

Cas Number:

1678-91-7

Molecular formula:

C8H16

IUPAC Name:

ethylcyclohexane

Test material form:

liquid: volatile

Specific details on test material used for the study:

CAS Number: 001678-91-7
SMILES : CCC1CCCCC1
CHEM : Ethyl cyclohexane
MOL FOR: C8 H16
MOL WT : 112.22

Radiolabelling:

no

Sampling and analysis

Details on sampling:

not applicable

Test solutions

Vehicle:

no

Details on preparation of test solutions, spiked fish food or sediment:

not applicable

Test organisms

Test organisms (species):

not specified

Details on test organisms:

not applicable

Test conditions

Hardness:

not applicable

Test temperature:

not applicable

pH:

not applicable

Dissolved oxygen:

not applicable

TOC:

not applicable

Salinity:

not applicable

Conductivity:

not applicable

Details on test conditions:

not applicable

Nominal and measured concentrations:

not applicable

Reference substance (positive control):

not required

Details on estimation of bioconcentration:

not applicable

Results and discussion

Bioaccumulation factor

Bioaccumulation factor 1

Key result

Temp.:

25 °C

Type:

BCF

Value:

474 L/kg

Basis:

whole body w.w.

Calculation basis:

other: not applicable

Remarks on result:

other: regression-based estimate

Bioaccumulation factor 2

Key result

Temp.:

25 °C

Type:

BCF

Value:

730.7 L/kg

Basis:

whole body w.w.

Calculation basis:

other: not applicable

Remarks on result:

other: Arnot-Gobas model (upper trophic)

Bioaccumulation factor 3

Key result

Temp.:

25 °C

Type:

BCF

Value:

827.6 L/kg

Basis:

whole body w.w.

Calculation basis:

other: not applicable

Remarks on result:

other: Arnot-Gobas model (mid trophic)

Bioaccumulation factor 4

Key result

Temp.:

25 °C

Type:

BCF

Value:

839.2 L/kg

Basis:

whole body w.w.

Calculation basis:

other: not applicable

Remarks on result:

other: Arnot-Gobas model (lower trophic)

Details on kinetic parameters:

not applicable

Metabolites:

not applicable

Results with reference substance (positive control):

not applicable

Any other information on results incl. tables

SMILES : CCC1CCCCC1

CHEM   :

MOL FOR: C8 H16

MOL WT : 112.22

--------------------------------- BCFBAF v3.01 --------------------------------

Summary Results:

 Log BCF (regression-based estimate):  2.68  (BCF = 474 L/kg wet-wt)

 Biotransformation Half-Life (days) :  2.19  (normalized to 10 g fish)

 Log BAF (Arnot-Gobas upper trophic):  2.87  (BAF = 737 L/kg wet-wt)

=============================

BCF (Bioconcentration Factor):

=============================

Log Kow  (estimated)  :  4.08

Log Kow (experimental):  4.56

Log Kow used by BCF estimates:  4.56

Equation Used to Make BCF estimate:

  Log BCF = 0.6598 log Kow - 0.333 + Correction

     Correction(s):                    Value

      No Applicable Correction Factors

  Estimated Log BCF =  2.676  (BCF = 473.9 L/kg wet-wt)

===========================================================

Whole Body Primary Biotransformation Rate Estimate for Fish:

===========================================================

------+-----+--------------------------------------------+---------+---------

TYPE | NUM | LOG BIOTRANSFORMATION FRAGMENT DESCRIPTION |  COEFF  |  VALUE  

------+-----+--------------------------------------------+---------+---------

Frag |  1  |  Methyl  [-CH3]                            |  0.2451 |  0.2451

Frag |  1  |  -CH2-  [linear]                           |  0.0242 |  0.0242

Frag |  5  |  -CH2-  [cyclic]                           |  0.0963 |  0.4813

Frag |  1  |  -CH -  [cyclic]                           |  0.0126 |  0.0126

L Kow|  *  |  Log Kow =   4.56 (experimental   )        |  0.3073 |  1.4015

MolWt|  *  |  Molecular Weight Parameter                |         | -0.2878

Const|  *  |  Equation Constant                         |         | -1.5058

============+============================================+=========+=========

  RESULT   |        LOG Bio Half-Life (days)            |         |  0.3398

  RESULT   |            Bio Half-Life (days)            |         |   2.187

  NOTE     |  Bio Half-Life Normalized to 10 g fish at 15 deg C   |

============+============================================+=========+=========

Biotransformation Rate Constant:

kM (Rate Constant):  0.317 /day (10 gram fish)

kM (Rate Constant):  0.1782 /day (100 gram fish)

kM (Rate Constant):  0.1002 /day (1 kg fish)

kM (Rate Constant):  0.05637 /day (10 kg fish)

Arnot-Gobas BCF & BAF Methods (including biotransformation rate estimates):

  Estimated Log BCF (upper trophic) =  2.864  (BCF = 730.7 L/kg wet-wt)

  Estimated Log BAF (upper trophic) =  2.868  (BAF = 737.2 L/kg wet-wt)

  Estimated Log BCF (mid trophic)   =  2.918  (BCF = 827.6 L/kg wet-wt)

  Estimated Log BAF (mid trophic)   =  2.940  (BAF = 870.6 L/kg wet-wt)

  Estimated Log BCF (lower trophic) =  2.924  (BCF = 839.2 L/kg wet-wt)

  Estimated Log BAF (lower trophic) =  2.986  (BAF = 967.4 L/kg wet-wt)

Arnot-Gobas BCF & BAF Methods (assuming a biotransformation rate of zero):

  Estimated Log BCF (upper trophic) =  3.537  (BCF = 3443 L/kg wet-wt)

  Estimated Log BAF (upper trophic) =  4.287  (BAF = 1.935e+004 L/kg wet-wt)

Applicability domain of the model (as given in the EPI SUITE User's Guide):

Currently there is no universally accepted definition of model domain.

Following minimum and maximum values for molecular weight and Kow values are given:

Molecular Weight:

Minimum MW: 68.08 (Furan)

Maximum MW: 991.80 Ionic: (2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-3,6-

bis[[4-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]azo]-, tetrasodium salt)

Maximum MW: 959.17 Non-Ionic: (Benzene, 1,1 -oxybis[2,3,4,5,6-pentabromo-)

Average MW: 244.00

Log Kow:

Minimum LogKow: -6.50 Ionic: (2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-3,6-bis[[4-[[2-(sulfooxy)ethyl]sulfonyl]phenyl]azo]-, tetrasodium salt)

Minimum LogKow: -1.37 Non-Ionic: (1,3,5-Triazine-2,4,6-triamine)

Maximum LogKow: 11.26 (Benzenamine, ar-octyl-N-(octylphenyl)-)

3. Adequacy of prediction

The substance ethylcyclohexane falls within the applicability domain described above and, therefore, the predicted value can be considered reliable.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Conclusions:

The BCF of ethylcyclohexane was calculated to be 474 - 839 L/kg. A measured Kow (4.56) was used to calculate the BCF.

Executive summary:

The bioconcentration of ethylcyclohexane was determined by a non-experimental calculation method.

Ethylcyclohexane is a slightly water soluble, non-polar organic substance.

The calculated BCF's were estimated to be in the range of 474 to 839 L/kg.