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Endpoint:
adsorption / desorption
Remarks:
other: QSAR assessment using US EPA On-Line EPI Suite™ KOCWIN v2.00 model
Type of information:
calculation (if not (Q)SAR)
Remarks:
estimated by calculation
Adequacy of study:
key study
Study period:
November 2013
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Validated QSAR calculation method, using EPIWIN suite, KOCWIN v2.00 model model. A QPRF is attached. The substance is recognised as part of the rulebase utilised by the EPI Suite model data set, and is in model Applicability Domain. Further details can be found within the appended report below or at http://www.epa.gov/oppt/exposure/pubs/episuite.htm. This system is recognised in ECHA Guidance document CHAPTER R.6 – QSARS AND GROUPING OF CHEMICALS, Pg 47
Qualifier:
no guideline followed
Principles of method if other than guideline:
The substance is a hydrocarbon UVCB. Standard tests for assessment of adsorption are intended for single substances and are not appropriate for this complex substance. It is unlikely that a study result would give anything other than a “greater than” limit value of the highest value available in the test. This endpoint is therefore characterized using quantitative structure property relationships for representative hydrocarbon structures that could be present within this UVCB substance. 70 proposed molecules are assessed, in order to provide a suitable range of likely values associated with the substance. Details on the KOCWIN v2.00 model programme are detailed below under "methods".
GLP compliance:
no
Type of method:
other: QSAR assessment using US EPA On-Line EPI Suite™ KOCWIN v2.00 model
Media:
other: QSAR assessment using US EPA On-Line EPI Suite™ KOCWIN v2.00 model
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material (migrated information):Not applicable - QSAR assessment.
Radiolabelling:
no
Test temperature:
Not applicable - QSAR assessment.
Details on study design: HPLC method:
Not applicable - QSAR assessment.
Analytical monitoring:
not required
Details on sampling:
Not applicable - QSAR assessment.
Details on matrix:
Not applicable - QSAR assessment.
Details on test conditions:
Not applicable - QSAR assessment.
Computational methods:
The Soil Adsorption Coefficient Program (KOCWIN) estimates the soil adsorption coeffiecient (Koc) of organic compounds. Koc can be defined as "the ratio of the amount of chemical adsorbed per unit weight of organic carbon (oc) in the soil or sediment to the concentration of the chemical in solution at equilibrium" (Lyman, 1990); it is represented by the following equation (Lyman, 1990): Koc = (ug adsorbed/g organic carbon) / (ug/mL solution)The units of Koc are typically expressed as either L/kg or mL/g.Koc provides an indication of the extent to which a chemical partitions between solid and solution phases in soil, or between water and sediment in aquatic ecosystems. Estimated values of Koc are often used in environmental fate assessment because measurement of Koc is expensive. Traditional estimation methods rely upon the octanol/water partition coefficient or related parameters, but the first-order molecular connectivity index (MCI) has been used successfully to predict Koc values for hydrophobic organic compounds (Sabljic, 1984, 1987; Bahnick and Doucette, 1988). The original KOCWIN program (PCKOC) used MCI and a series of group contribution factors to predict Koc (Meylan et al., 1992). This group contribution method was shown to outperform traditional estimation methods based on octanol/water partition coefficients and water solubility. Since the introduction of the original PCKOC program in 1992, the number of available experimental Koc values has grown significantly. Using an expanded experimental dataset and the original PCKOC methodology, the QSAR equations were re-regressed to derive updated coefficient values. In addition, several new group contribution factors (correction factors) were added to improve estimation accuracy. Also, the updated KOCWIN program includes a separate Koc estimate based upon Log Kow (rather than MCI). A brief description of the estimation methodology and accuracy is presented in the Methodology section and Accuracy section of the programme.KOCWIN requires only a chemical structure to make these predictions. Structures are entered into KOCWIN by SMILES (Simplified Molecular Input Line Entry System) notations. The following journal article explains the MCI prediction methodology and its use:(1) Meylan, W., P.H. Howard and R.S. Boethling, "Molecular Topology/Fragment Contribution Method for Predicting Soil Sorption Coefficients", Environ. Sci. Technol. 26: 1560-7 (1992).Journal abstract:"The first-order molecular connectivity index (MCI) has been successfully used to predict soil sorption coefficients (Koc) for nonpolar organics, but extension of the model to polar compounds has been problematic. To address this, we developed a new estimation method based on MCI and series of statistically derived fragment contribution factors for polar compounds. After developing an extensive database of measured Koc values, we divided the dataset into a training set of 189 chemicals and an independent validation set of 205 chemicals. Two linear regressions were then performed. First, measured log Koc values for nonpolar compounds in the training set were correlated with MCI. The second regression was developed by using the deviations between measured log Koc and the log Koc estimated with the nonpolar equation and the number of certain structural fragments in the polar compounds. The final equation for predicting log Koc accounts for 96% and 86% of the variation in the measured values for the training and validation sets, respectively. Results also show that the model outperforms and covers a wider range of chemical structures than do models based on octanol-water partition coefficients (Kow) or water solubility."
Type:
log Koc
Value:
>= 4.28 - <= 16.732 dimensionless
Temp.:
25 °C
Remarks on result:
other: Calculated range of values using EPIWIN KOCWIN v2.00 model
Details on results (HPLC method):
Not applicable - QSAR assessment.
Adsorption and desorption constants:
Not applicable - QSAR assessment.
Recovery of test material:
Not applicable - QSAR assessment.
Concentration of test substance at end of adsorption equilibration period:
Not applicable - QSAR assessment.
Concentration of test substance at end of desorption equilibration period:
Not applicable - QSAR assessment.
Details on results (Batch equilibrium method):
Not applicable - QSAR assessment.
Statistics:
Not applicable - QSAR assessment.

Tabulated data from evaluation of various potential structures present in NovaSpec 450 Base Oil

Derivation

SMILES Code

Molecular Formula

MW

Log Kow calculated using KOCWIN v2.00

1

M

CC(C)CCCC(C)CCCC(C)CC

C15H32

212.41

4.279

2

M-C8

CC(C)C(CCC(C)CCCC(C)CC)C(CC)CCCCC

C23H48

324.63

6.3107

3

M-C10

CC(C)C(CCC(C)CCCC(C)CC)C(CCCC)CCCCC

C25H52

338.65

6.832

4

M-C12

CC(C)C(CCC(C)CCCC(C)CC)C(CCCCC)CCCCCC

C27H56

380.73

7.3533

5

M-C14

CC(C)C(CCC(C)CCCC(C)CC)C(CCCCCCCC)CCCCC

C29H60

408.79

7.8746

6

M-C16

CC(C)C(CCC(C)CCCC(C)CC)C(CCCCCCCCCC)CCCCC

C31H64

436.84

8.3959

7

M-C8

CCC(CCCCC)C(CCC(C)C)C(C)CCCC(C)CC

C23H48

324.63

6.3107

8

M-C8

CCC(CCCCC)C(CCC(C)CC)C(C)CCCC(C)C

C23H48

324.63

6.3107

9

M-C10

CC(CCCC(C)CCCC(C)CC)CC(CCCCC)CCCC

C25H52

338.65

6.8698

10

M-C10

CC(CCCC(C)CC)C(CCC(C)C)C(CCCCC)CCCCCC

C25H52

338.65

7.3533

11

M-C12

CC(CCCC(C)CC)C(CCC(C)C)C(CCCCC)CCCCCC

C27H56

380.73

7.3533

12

M-C12

CC(CCCC(C)C)C(CCC(C)CC)C(CCCCCC)CCCCC

C27H56

380.73

7.3533

13

M-C12

CC(CC)C(CCC(C)CCCC(C)C)C(CCCCC)CCCCCC

C27H56

380.73

7.3533

14

M-C12

CC(CCCC(C)C)C(CCC(C)CC)C(CCCC)CCCCCCC

C27H56

380.73

7.3533

15

M-C14

CC(CC(CCCCCC)CCCCCCC)CCCC(C)CCCC(C)CC

C29H60

408.79

7.9124

16

M-C14

CC(CCCC(C)CC)C(CCC(C)C)C(CCCCC)CCCCCCCC

C29H60

408.79

7.8746

17

M-C14

CC(CC)C(CCC(C)CCCC(C)C)C(CCCCC)CCCCCCCC

C29H60

408.79

7.8746

18

M-C14

CC(CCCC(C)CC)C(CCC(C)C)C(CCCCCCCCC)CCCC

C29H60

408.79

7.8746

19

M-C14

CC(CCCC(C)C)C(CCC(C)CC)C(CCCCCCC)CCCCCC

C29H60

408.79

7.8746

20

M-C16

CC(CCCC(C)CCCC(C)CC)CC(CCCCCCCC)CCCCCCC

C31H64

436.84

8.4337

21

M-C16

CC(C)CCC(C(CCCCCCCC)CCCCCCC)C(C)CCCC(C)CC

C31H64

436.84

8.3959

22

M-C16

CC(C)C(CCCCCCCCCCCCCCCC)CCC(C)CCCC(C)CC

C31H64

436.84

8.4227

23

M-Farn

CC(CC(CCC(C)CCCC(C)CC)C(C)C)CCCC(C)CCCC(C)CC

C30H62

422.81

7.996

24

M-Farn

CC(C)CCCC(CCCC(C)CC)CC(CCC(C)CC)C(C)CCCC(C)C

C30H62

422.81

7.996

25

M-Farn-C8

CC(C)CCCC(C)CCC(CC(CCCC(C)CC)CCC(C(CC)CCCCC)C(C)C)C(C)CC

C38H78

535.03

10.0277

26

M-Farn-C8

CC(CCCC(C)CCCC(C)CCCC(C)CCCC(C)CC)C(CCC(C)C)CCCCCCCC

C38H78

535.03

10.0812

27

M-Farn-C10

CC(C)CCCC(C)CCC(CC(CCCC(C)C(CCC(C)C)C(CCCCCCC)CC)CC)C(C)CC

C40H82

563.08

10.549

28

M-Farn-C12

CC(CCCC(C)C)C(CCC(CC(CCC(C)CCCC(C)C)C(C)CC)CC)C(CCCCC)CCCCCC

C42H86

591.13

11.0703

29

M-Farn-C14

CC(C)C(CCC(C)CCCC(C)CC)C(CC(C)CCCC(C)CC)C(C(C)C)C(CCCC)CCCCCCCCC

C44H90

619.18

11.5538

30

M-Farn-C16

CC(CC(CCCC)CCCCCCCCCCC)CCCC(CCCC(C)CC)CC(CCC(C)C)C(C)CCCC(C)CC

C46H94

647.24

12.1507

31

M-C8-C12

CCCCCC(CC(CC)CCCC(C)C(CCC(C)C)C(CCCCC)CC)CCCCCC

C35H72

492.95

9.4228

32

M-C8-C14

CCCC(CCCCCCCCCC)CC(CCC(CCCCCCCC)C(C)C)CCCC(C)CC

C37H76

520.99

9.9708

33

M-C8-C16

CC(CCCC(C)CC)CCCC(CCCCCCCCC)CC(CCCC)CCCCCCCCCCC

C39H80

549.05

10.5387

34

M-C10-C8

CCCCC(CCCCC)C(CCC(CC(C)CCCCCC)CCCC(C)CC)C(C)C

C33H68

464.89

8.8817

35

M-C10-C12

CCC(CCCCCCC)C(CCC(C)CC)C(C)CCCC(C)CC(CCCCCC)CCCCC

C37H76

520.99

9.9441

36

M-C10-C16

CCC(CCCCCCC)C(CCC(C)CC)C(C)CCCC(C)CC(CCCCC)CCCCCCCCCC

C41H84

577.11

10.9867

37

M-C12-C8

CC(CCCCCC)CC(CC)CCCC(C)C(CCC(C)C)C(CCCCC)CCCCCC

C35H72

492.95

9.403

38

M-C12-C14

CC(CC(CCCCCCCC)CCCCC)CCC(C(CCCCC)CCCCCC)C(C)CCCC(C)CC

C41H84

577.11

10.9867

39

M-C12-C16

CCCCCC(CC(CCCC(C)CC)CCCC(C)CCCCCCCCCCCCC)CCCCCCCCCC

C43H88

605.16

11.5813

40

M-C14-C8

CC(C)C(CCC(CCCC(C)CC)CC(C)CCCCCC)C(CCCCC)CCCCCCCC

C37H76

520.99

9.9243

41

M-C14-C10

CCCCC(CCCCCCCCC)C(CCC(C)CC)C(CC(C)CCCCCCCC)CCCC(C)C

C39H80

549.05

10.4456

42

M-C14-C16

CCCCCCCCCCCC(CCCC)CC(CCCC(C)CC)CCCC(C)CC(CCCCCCCC)CCCCC

C45H92

633.21

12.0671

43

M-C16-C8

CC(C)C(CCC(CC(C)CCCCCC)CCCC(C)CC)C(CCCCCCCCCC)CCCCC

C39H80

549.05

10.4456

44

M-C16-C16

CC(CC(CCCCCCCCCC)CCCCC)C(CCC(C)CCCC(C)CC)CCCCCCCCCCCCCCCC

C47H96

661.26

12.5773

45

M-Farn-Farn (Deriv 1)

CC(C)CCCC(C)CCCC(CC)CC(CCC(C)CC)C(C)CCCC(C)CC(CCC(C)CC)C(C)CCCC(C)C

C45H92

633.21

11.713

46

M-Farn-Farn (Deriv 2)

CC(CCCC(C)CCCC(C)CCCC(C)CC)C(CC(C)CCCC(C)CCCC(C)CC)CCC(C)CCCC(C)C

C45H92

633.21

11.7397

47

M-Farn-Farn (Deriv 3)

CC(CC(CCC(C)CCCC(C)CC)C(C)CC(CCC(C)CCCC(C)CC)C(C)C)CCCC(C)CCCC(C)CC

C45H92

633.21

11.713

48

M-C8-C8-C8

CC(C)C(CCC(CC(C)CCCCCC)CCC(CCCCCCCC)C(C)CC)C(CC)CCCCC

C39H80

549.05

10.4188

49

M-C10-C10-C10

CC(CC(CC(C)CC)CCCCCCCCCC)C(CCCCCCCCCC)CCC(C)CCCCCCCCCCC

C45H92

633.21

12.056

50

M-C12-C12-C12

CC(C(C)CCCC(CCCC(C)CC(C)CCCCCCCCCC)CC(C)CCCCCCCCCC)C(CCCCCC)CCCCC

C51H104

717.37

13.518

51

M-C14-C14-C14

CCCCCC(CC(CCCC(C)C(CCC(C)CCCCCCCCCCCCCCC)C(CCCCCCCC)CCCCC)CC)CCCCCCCC

C57H116

801.53

15.1769

52

M-C16-C16-C16

CCCCCCCCCC(CC(CCCC(C)C(CCCCCCCCCCCCCCCC)CCC(C)CC(CCCCCCC)CCCCCCCC)CC)CCCCCC

C63H128

885.69

16.732

53

M-Farn-Farn-C8

CC(CCCC(CC(CCCCC)CC)C(CCC(C)C)C(CCC(C)C)C(C)CCCC(C)CC)CCCC(CCCC(C)C)CCCC(C)CC

C53H108

745.42

13.7714

54

M-Farn-Farn-C10

CC(CCCC(C)CC(CC(CC(C)CCCC(C)CCCC(C)CC)C(C)C(C)CCCCCCCCCC)C(C)CCCC(C)C)CCCC(C)CC

C55H112

773.48

14.2729

55

M-Farn-Farn-C12

CC(CCCC(C)C)C(CCC(C)CC)CC(CCCC(C)CCC(CC(C)CCCC(C)CCCC(C)CC)C(C)CC)CC(CCCCCC)CCCCC

C57H116

801.53

14.8251

56

M-Farn-Farn-C14

CC(CC(CCC(C)CCC(CCCC(C)C)CCCC(C)CC)C(C)CCCC(C)CC)C(CCC(C)CCCC(C)CC)C(CCCCCCC)CCCCCC

C59H120

829.58

15.3551

57

M-Farn-Farn-C16

CC(C)CCCC(CCCC(C)CC)CCC(CCCC(C)CCC(CCCCCCCCC)CCCCCC)C(CC(CCCC(C)CC)CCCC(C)C)CCC(C)C

C61H124

857.64

15.8944

58

M-Farn-C8-C10

CC(CCCC(C)CC)CCCC(C)CCC(CCCC(C)CCCC(C)C(C)CCCCCCCCCC)CCCCCCCCC

C48H98

647.24

12.7075

59

M-Farn-C10-C14

CC(CCCC(C)CC)CCCC(CCC(CCCC(C)CCCC(C)CCCCCCCCCCC)CC)CC(CCCC)CCCCCCCCC

C54H110

759.45

14.3023

60

M-Farn-C14-C16

CCCCCCCCC(CCCCC)C(CCC(C)C)C(C)CCCC(CCC(CC)C(CCC(C)CCCC(C)C)C(CCCCCCC)CCCCCCCC)CC

C60H112

843.61

15.7551

61

M-Farn-C16-C16

CC(CCCC(C)CC)C(CCC(C)CCC(CC(CC)CCCCCCCCCCCCC)CCCC(C)CCCC(C)CC)CCCCCCCCCCCCCCCC

C62H126

871.66

16.3409

62

M-Farn-C8-C16

CCCC(CCCC)C(CCC(C)CC)C(CCC(CCCC(C)CC)CCCC(C)CC(CCCCCCCCCC)CCCCC)CCCC(C)C

C54H110

759.45

14.2289

63

M-C8-C10-C12

CC(CCCC(C)CCCC(CC(CCCCC)CC)C(C)C(CC)CCCCCCC)CCCCCCCCCCCCC

C45H92

633.21

12.0293

64

M-C12-C14-C16

CCCCC(CC(CCCC(C)C(C)C(CCCCCC)CCCCCCCCC)CCCC(C)CCCCCCCCCCCCC)CCCCCCCCC

C57H116

801.53

15.1571

65

M-C8-C12-C16

CC(C(CC(C)CCCCCCCCCC)CCCC(C)CCCC(C)CC(CCCCCCCC)CCCCCCC)C(CCCCC)CC

C51H104

717.37

13.5379

66

M-C10-C12-C14

CCCCC(CCCCCCC)C(CCC(C)CCC(CCCCC)CCCC)C(C)CCCC(C)CC(CCCCCC)CCCCCCC

C51H104

717.37

13.5577

67

M-C8-C14-C16

CC(CCC(CCCCCCCC)C(C)CCCC(C)CCC(C)CCCCCCCCCCCC)CC(CCCCCCCCC)CCCCCC

C53H108

745.42

14.0859

68

M-Farn-Farn-Farn (Deriv 1)

CC(CC(CCC(C)CC)C(CC(CCC(C)CCCC(C)CC)C(C)C)CCCC(C)CCC(CCCC(C)CCCC(C)C)CC)CCCC(C)CCCC(C)CC

C60H112

843.61

15.4765

69

M-Farn-Farn-Farn (Deriv 2)

CC(C)C(CCC(C)CCCC(C)CC)CC(C)C(CCC(C)C(CC(C)CCCC(C)CCCC(C)CC)CCC(C)CC)C(CCC(C)CCCC(C)CC)C(C)C

C60H112

843.61

15.3922

70

M-Farn-Farn-Farn (Deriv 3)

CC(CC)CCCC(C)CCCC(C)CCC(CCCC(C)CC(C)C(C)CCCC(C)C(CCC(C)C)C(CCC(C)C)C(C)CCCC(C)CC)CCCC(C)CC

C60H112

843.61

15.4189

 

Validity criteria fulfilled:
yes
Conclusions:
Using the US EPA On-Line EPI Suite™ KOCWIN v2.00 model, the log Koc range is predicted to be 4.28 to 16.732. Using the US EPA On-Line EPI Suite™ KOCWIN v2.00 model, the log Koc range is predicted to be 4.28 to 16.732. This is anticipated to be appropriate, based on the predicted water solubility and hydrocarbon nature of the substance.
Executive summary:

The substance is a hydrocarbon UVCB. Standard tests for assessment of adsorption are intended for single substances and are not appropriate for this complex substance. It is unlikely that a study result would give anything other than a “greater than” limit value of the highest value available in the test. This endpoint is therefore characterized using quantitative structure property relationships for representative hydrocarbon structures that could be present within this UVCB substance. 70 proposed molecules are assessed, in order to provide a suitable range of likely values associated with the substance.

Using the US EPA On-Line EPI Suite™ KOCWIN v2.00 model, the log Kocrange is predicted to be 4.28 to 16.732. Using the US EPA On-Line EPI Suite™ KOCWIN v2.00 model, the log Koc range is predicted to be 4.28 to 16.732. This is anticipated to be appropriate, based on the predicted water solubility and hydrocarbon nature of the substance.

Log Koc can provide insight as to whether a material will cling to soils or sediments in water and whether they will desorb or be tightly bound. Based on information from NTIS ((Review of Exposure Assessment Guidelines, September 1996), approximate indications of relative soil absorption potential are as follows:

Low potential: Koc = 1 to 100, log Koc = 0 - 2
Moderate potential: Koc = 100 to 10,000, log Koc = 2 - 4
High potential: Koc = 10,000 to 10,000,000, log Koc 4 - 7
A high potential would indicate that a material would bind tightly to soils and sediments and thus, reduce overall exposure potential.

Endpoint:
adsorption / desorption
Remarks:
adsorption
Type of information:
experimental study
Adequacy of study:
key study
Study period:
25 February 2015
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study could not be performed to the recognised OECD & EU test guidelines due to the nature of the test material.
Qualifier:
no guideline followed
Principles of method if other than guideline:
During the adsorption coefficient study we tried to find proper analytical methods which separate the test item and the pesticide standards.With the common HPLC eluents (acetonitrile or methanol) we can separate the pesticide standards but the test item did not elute from the column. When we used stronger organic solvents we are able to elute the test item but the standards elute together and this prevents the calibration.We know for sure, that the elution time is of the test item is much longer than the last eluting standard which means that the adsorption coefficient of the test item is higher than the last standard (DDT KOC=5.6). Therefore we cannot give an exact value as a result of the test only estimation. But this means that we cannot perform the test according to the guideline.
GLP compliance:
no
Remarks:
Study could not be performed to the recognised OECD & EU test guidelines due to the nature of the test material.
Type of method:
HPLC estimation method
Media:
other: Not specified
Specific details on test material used for the study:
Details on properties of test surrogate or analogue material:No further details specified in the study report.
Radiolabelling:
no
Test temperature:
Not specified
Details on study design: HPLC method:
OBJECTIVE OF THE STUDY
The purpose of the study is to estimate the adsorption coefficient Koc of test item using an HPLC method. This method is applicable for substances, which have log Koc value ranging from 0 to 6.During the adsorption coefficient study we tried to find proper analytical methods which separate the test item and the pesticide standards.With the common HPLC eluents (acetonitrile or methanol) we can separate the pesticide standards but the test item did not elute from the column. When we used stronger organic solvents we are able to elute the test item but the standards elute together and this prevents the calibration.We know for sure, that the elution time is of the test item is much longer than the last eluting standard which means that the adsorption coefficient of the test item is higher than the last standard (DDT KOC=5.6). Therefore we cannot give an exact value as a result of the test only estimation. But this means that we cannot perform the test according to the guideline.
Analytical monitoring:
not specified
Type:
Koc
Value:
> 5.56
Remarks on result:
other: Temperature and % Org. carbon not specified in the study report.
Details on results (HPLC method):
During the adsorption coefficient study we tried to find proper analytical methods which separate the test item and the pesticide standards.With the common HPLC eluents (acetonitrile or methanol) we can separate the pesticide standards but the test item did not elute from the column. When we used stronger organic solvents we are able to elute the test item but the standards elute together and this prevents the calibration.We know for sure, that the elution time is of the test item is much longer than the last eluting standard which means that the adsorption coefficient of the test item is higher than the last standard (DDT KOC=5.6). Therefore we cannot give an exact value as a result of the test only estimation. But this means that we cannot perform the test according to the guideline.
Conclusions:
Log Koc >= 5.6
Executive summary:

OBJECTIVE OF THE STUDY

The purpose of the study is to estimate the adsorption coefficient Koc of test item using an HPLC method. This method is applicable for substances, which have log Koc value ranging from 0 to 6.

 

During the adsorption coefficient study we tried to find proper analytical methods which separate the test item and the pesticide standards.

With the common HPLC eluents (acetonitrile or methanol) we can separate the pesticide standards but the test item did not elute from the column. When we used stronger organic solvents we are able to elute the test item but the standards elute together and this prevents the calibration.

We know for sure, that the elution time is of the test item is much longer than the last eluting standard which means that the adsorption coefficient of the test item is higher than the last standard (DDT KOC=5.6). Therefore we cannot give an exact value as a result of the test only estimation. But this means that we cannot perform the test according to the guideline.

Description of key information

Assessment of soil adsorption via QSAR

Key value for chemical safety assessment

Koc at 20 °C:
53 951 062 251 512 680

Additional information

The substance is a hydrocarbon UVCB. Standard tests for assessment of adsorption are intended for single substances and are not appropriate for this complex substance. It is unlikely that a study result would give anything other than a “greater than” limit value of the highest value available in the test. This endpoint is therefore characterized using quantitative structure property relationships for representative hydrocarbon structures that could be present within this UVCB substance. 70 proposed molecules are assessed, in order to provide a suitable range of likely values associated with the substance.

Using the US EPA On-Line EPI Suite™ KOCWIN v2.00 model, the log Koc range is predicted to be 4.28 to 16.732. This is anticipated to be appropriate, based on the predicted water solubility and hydrocarbon nature of the substance.

Log Koc can provide insight as to whether a material will cling to soils or sediments in water and whether they will desorb or be tightly bound. Based on information from NTIS ((Review of Exposure Assessment Guidelines, September 1996), approximate indications of relative soil absorption potential are as follows:

Low potential: Koc = 1 to 100, log Koc = 0 - 2
Moderate potential: Koc = 100 to 10,000, log Koc = 2 - 4
High potential: Koc = 10,000 to 10,000,000, log Koc 4 - 7


A high potential would indicate that a material would bind tightly to soils and sediments and thus, reduce overall exposure potential.

Short report

The intention was to estimate the adsorption coefficient Koc of test item using an HPLC method. This method is applicable for substances, which have log Koc value ranging from 0 to 6.

During the test efforts were made to identify the appropriate analytical method which seperates the test item and the pesticide standards. With the common HPLC eluents (acetonitrile or methanol) the pesticide standards were separated but the test item did not elute from the column. When we used stronger organic solvents we are able to elute the test item but the standards elute together and this prevents the calibration.

The elution time is of the test item is much longer than the last eluting standard which means that the adsorption coefficient of the test item is higher than the last standard (DDT KOC=5.6). Therefore it is not possible to determine the exact value as a result of the test, only an estimation. But this means that it is not possible to perform the test according to the guideline.

[LogKoc: 16.732]