1,4-bis[[4-(1,1-dimethylethyl)phenyl]amino]-5,8-dihydroxyanthraquinone

Adsorption / desorption

Link to relevant study record(s)

Reference

Endpoint:

adsorption / desorption: screening

Remarks:

adsorption

Type of information:

(Q)SAR

Adequacy of study:

key study

Study period:

2017

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

results derived from a valid (Q)SAR model and falling into its applicability domain, with adequate and reliable documentation / justification

Justification for type of information:

1. SOFTWARE
Individual model KOCWIN included in the Estimation Programs Interface (EPI) Suite.

2. MODEL (incl. version number)
KOCWIN v2.00 included in EPISuite v 4.11, 2000-2012.

3. SMILES OR OTHER IDENTIFIERS USED AS INPUT FOR THE MODEL
A CAS number was entered in the initial data entry screen. In the structure window, the molecular weight, structural formula and the structure of the input SMILES notation is shown.

4. SCIENTIFIC VALIDITY OF THE (Q)SAR MODEL
a. Defined endpoint: Organic carbon partition coefficient, given as log Koc.
b. Dependent variable: KOCWIN estimates log Koc with two separate estimation methodologies:
(1) Estimation using first order Molecular Connecitivity Index (MCI),
(2) Estimation using log Kow (octanol-water partition coefficient)
c. Algorithm:
Log Koc according to MCI method is calculated using the formula:
log Koc = 0.5213 MCI + 0.60 + ΣPfN
(ΣPfN is the sum of all relevant correction factor coefficients multiplied by the number (N) of that factor in each chemical structure)
Log Koc according to the log Kow method is calculated using two formulas (depending on the polarity of the substance):
log Koc = 0.8679 log Kow - 0.0004 (Non-polar substances)
log Koc = 0.55313 log Kow + 0.9251 + ΣPfN (polar substances)

d. Descriptor values:
Log Kow method:
For estimation of log Koc according to log Kow method an experimentally determined log Kow of 10.7 was used (Currenta, 2016).

e. Applicability domain: The minimum and maximum values for molecular weight are the following:
Training Set Molecular Weights: 32.04-665.02 g/mol,
Validation Set Molecular Weights: 27.03-991.15 g/mol

f. Statistics for goodness-of-fit:

Statistical accuracy of MCI methodology for training and validation set:
i. Training without corrections:
Number: 69
R^2 correction coefficient: 0.967
Standard deviation (log Koc): 0.247
Average deviation (log Koc): 0.199

ii. Training with corrections:
Number: 447
R^2 correction coefficient: 0.900
Standard deviation (log Koc): 0.340
Average deviation (log Koc): 0.273

iii. Validation data set:
Number: 158
R^2 correction coefficient: 0.850
Standard deviation (log Koc): 0.583
Average deviation (log Koc): 0.459

Statistical accuracy of Log Koc methodology:
i. Training without corrections:
Number: 68
R^2 correction coefficient: 0.877
Standard deviation: 0.478
Average deviation: 0.371

ii. Training with corrections:
Number: 447
R^2 correction coefficient: 0.855
Standard deviation (log Koc): 0.396
Average deviation (log Koc): 0.307

iii. Validation data set:
Number: 150
R^2 correction coefficient: 0.778
Standard deviation (log Koc): 0.679
Average deviation (log Koc): 0.494

g. Mechanistic interpretation: Log Koc is estimated based on the likeliness of a substance for sorption to surfaces of soil/sediment particles. This characteristic is triggered by lipophilic character of substances but may be modified by certain molecular fragments that need to be considered by application of correction factors. The Log Koc is a physical inherent property used extensively to describe a chemical’s likeliness to adsorb to organic carbon.
h. The uncertainty of the prediction (OECD principle 4): Solvent Green 28 is not highly complex and the rules applied for the substance appear appropriate. An individual uncertainty for the investigated substance is not available.

5. APPLICABILITY DOMAIN
a. Descriptor domains:
i. Molecular weights: With a molecular weight of 534.64 g/mole Solvent green 28 is within the range of the training set (32 - 665 g/mol) as well as in the range of the validation set (27 -– 991 g/mol).
ii. Structural fragment domain: Regarding the structure of Solvent Green 28 the fragment descriptors found by the program are complete and listed in Appendix D (KOCWIN Fragment and Correction Factor descriptors). For log Koc estimation according to MCI method no fragment descriptors were applied. For estimation of log Koc according to log Kow method the log Kow of 10.7 (experimentally determined, Currenta, 2016) was used.
iii. Mechanism domain: No information available.
iv. Metabolic domain: Not relevant.
b. Structural analogues: No information available
i. Considerations on structural analogues: No information available

6. ADEQUACY OF THE RESULT
a. Regulatory purpose: The data may be used under any regulatory purpose.
b. Approach for regulatory interpretation of the model result: If no experimental data are available, the estimated value may be used to fill data gaps needed for hazard and risk assessment, classification and labelling and PBT / vPvB assessment. Further the value is used for other calculations.
c. Outcome: The prediction of organic carbon partition coefficient yields a useful result for further evaluation.
d. Conclusion: The result is considered as useful for regulatory purposes.

Guideline:

other: REACH guidance QSARs R6, May/July 2008

Principles of method if other than guideline:

Estimation Program Interface EPI-Suite version 4.11: KOCWIN (v2.00) for the estimation of the organic carbon-normalized sorption coefficient for soil and sediment (Koc).
The Estimation Program Interface was developed by the US Environmental Agency's Office of Pollution Prevention and Toxics, and Syracuse Research Corporation (SRC). © 2000 - 2012 U.S. Environmental Protection Agency for EPI SuiteTM (Published online in November 2012).

GLP compliance:

no

Type of method:

other: Estimation

Media:

soil

Radiolabelling:

no

Key result

Type:

log Koc

Value:

8.034 dimensionless

Remarks on result:

other: calculation (logKow method)

Type:

log Koc

Value:

8.178 dimensionless

Remarks on result:

other: calculation (MCI method)

Key result

Phase system:

other: Koc

Type:

other: Koc

Value:

110 000 000 L/kg

Remarks on result:

other: calculation (logKow method)

Phase system:

other: Koc

Type:

other: Koc

Value:

150 000 000 L/kg

Remarks on result:

other: calculation (MCI method)

Validity of the model:

1. Defined Endpoint: Organic carbon partition coefficient, given as logarithmic Koc and Koc

2. Unambigous algorithm: The molecule is first classified as a polar substance. Based on structure of the molecule, the following fragments were applied: 2 nitrogen (non fused aromatic ring), 2 ketone (-C-CO-C-), quinone (diketone ring) and 2 aromatic hydroxy (aromatic-OH). The number of times of the fragments that occurs in the structure of the substance applied by the program is verified. For estimation of logKoc according to the logKow method the experimentally determined logKow of 10.7 was used by the program.

3. Applicable domain: With a molecular weight of 534.64 g/mole the substance is within the range of the training set (32 - 665 g/mole) as well as in the validation set (27 - 991 g/mole). Regarding the structure of Solvent green 28 the fragment descriptors found by the program are complete.

4a. Statistical characteristics (MCI method): N training set without corrections = 69; N training set with correction = 447; N validation set = 158; Correction coefficient of the total training set without corrections r² = 0.967; Correlation coefficient of the total training set with corrections r² = 0.900; Correlation coefficient of the total validation set r² = 0.850.

4b. Statistical characteristics (Kow method): N training set without corrections = 68; N training set with correction = 447; N validation set = 150; Correction coefficient of the total training set without corrections r² = 0.877; Correlation coefficient of the total training set with corrections r² = 0.855; Correlation coefficient of the total validation set r² = 0.778.

5. Mechanistic interpretation: Log Koc is estimated based on the likeliness of a substance for sorption to surfaces of soil/sediment particles. The log Koc is a physical inherent property used extensively to describe a chemical's likeliness to adsob to organic carbon.

Adequacy of prediction: The result for Solvent green 28 falls within the applicability domain described above and the estimation rules applied for the substance appears appropriate.

Validity criteria fulfilled:

not applicable

Conclusions:

The QSAR determination of the carbon partition coefficient for Solvent green 28 using the model KOCWIN included in the Estimation Program Interface (EPI) Suite v4.11 revealed values of 1.1*10E+08 L/kg (logKow method) and 1.5*10E+08 L/kg  (MCI method) for the unaffected molecule of the substance as any decomposition (e.g. hydrolysis) of the substance is not taken into account by the program.

Executive summary:

The organic carbon partition coefficient (Koc) for Solvent green 28 was predicted using the QSAR calculation of the Estimation Program Interface (EPI) Suite v 4.11. The Koc was estimated to be 1.1 x 10⁰⁸ L/kg (logKow method), and 1.5 x 10⁰⁸ L/kg (MCI method). The results relate to the unaffected molecule of the substance as any decomposition (e.g. hydrolysis) of the substance is not taken into account by the program.

Description of key information

C.I. Solvent Green 28, Key, Rel 2; QSAR ((EPI) Suite v4.11); Allmendinger (2017): Koc=1.1*10⁰⁸ L/kg /log Koc=8.0 (logKow method) 

C.I. Solvent Green 28, Key, Rel 2; QSAR ((EPI) Suite v4.11); Allmendinger (2017): Koc=1.5*10⁰⁸ L/kg/ log Koc=8.2 (MCI method) 

 

 

Key value for chemical safety assessment

Koc at 20 °C:

110 000 000

Additional information

As the adsorption coefficient (Koc) of C.I Solvent Green 28 is 110 000 000 (Allmending, 2017), the result indicates that the substance is immobile in soils according to McCall et al. (1981).

Range of Koc	Mobility class
0-50	Very high
50-150	High
150-500	Medium
500-2000	Low
2000-5000	Slightly
>5000	Immobile

McCall P.J., Laskowski D.A., Swann R.L., and Dishburger H.J., (1981), “Measurement of sorption coefficients of organic chemicals and their use, in environmental fate analysis”, in Test Protocols for Environmental Fate and Movement of Toxicants. Proceedings of AOAC Symposium, AOAC,Washington DC

Category approach:

A category approach has been defined (see attached justification document in section 13). The category consists of substances all having the diamino-anthraquinone structure as a common moiety which is linked to phenyl groups via the amino groups. Differences within the category are described by various alkyl groups bound to the phenyl groups. All substances included in the category approach are poorly water soluble with high adsorption coefficient (log Koc>6), high partition coefficient (logKow>8) and not readily biodegradable.

Data available on other members of the category confirmed the immobile behavior of the substances:

Reinblau RLW (CAS n° 41611-76-1)	OECD-TG 121	logKoc value = 6.2 / Koc=1 584 893 L/kg
Reinblau RLW (CAS n°41611-76-1)	QSAR (EPI) Suite v4.11	logKoc value =6.5 / Koc= 3456000 L/kg (Log Kow method) logKoc value = 7.7 / Koc= 48560000 L/kg (MCI method)
Reinblau BLW (CAS n°32724-62-2)	QSAR (EPI) Suite v4.11	logKoc value = 6.5 / Koc= 3456000 L/kg (Log Kow method) logKoc value = 8.7 / Koc= 454 800 000 L/kg (MCI method)
Violet 36 (CAS n° 82-16-6)	QSAR (EPI) Suite v4.11	logKoc value = 6.4 / Koc=2 400 000 L/kg (Log Kow method) logKoc value = 6.7 / Koc=4 800 000 L/kg (MCI method)
Green 3 (CAS n° 128-80-3)	QSAR (EPI) Suite v4.11	logKoc value =6.3 / Koc= 2100000 L/kg (Log Kow method) logKoc value = 6.7 / Koc= 4800000 L/kg (MCI method)
Blue 104 (Cas n° 116-75-6)	QSAR (EPI) Suite v4.11	logKoc value = 6.7 / Koc=5 100 000 L/kg  (Log Kow method) logKoc value = 7. 5 / Koc=34000000 L/kg (MCI method)