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Reference
Endpoint:
adsorption / desorption
Remarks:
adsorption
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
weight of evidence
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Justification for type of information:
Estimated data generated using the EPI Suite model developed by the USEPA.
Qualifier:
according to
Guideline:
other: Modeling database
Principles of method if other than guideline:
Prediction done using KOCWIN Program (v2.00)
GLP compliance:
not specified
Type of method:
other: MCI Method
Media:
soil
Specific details on test material used for the study:
- Name of the test material (IUPAC Name): Calcium 3-hydroxy-4-[(4-methyl-2-sulfonatophenyl)diazenyl]-2-naphthoate- Common Name: D & C Red no. 7, C. I. Pigment 57:1- InChI: 1S/C18H14N2O6S.Ca/c1-10-6-7-14(15(8-10)27(24,25)26)19-20-16-12-5-3-2-4-11(12)9-13(17(16)21)18(22)23;/h2-9,21H,1H3,(H,22,23)(H,24,25,26);/q;+2/p-2/b20-19+;- Smiles: c12c(c(c(C(=O)[O-])cc1cccc2)O)\N=N\c1c(cc(C)cc1)S(=O)(=O)[O-].[Ca+2]- Molecular formula : C18H12CaN2O6S- Molecular weight : 424.445 g/mol- Substance type: Organic- Physical state: Solid
Radiolabelling:
not specified
Test temperature:
25 deg.C
Analytical monitoring:
not specified
Key result
Type:
Koc
Value:
8 321 L/kg
Temp.:
25 °C
Remarks on result:
other: Log Koc= 3.9202 (estimated by MCI method)
Transformation products:
not specified

KOCWIN Program (v2.00) Results:

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

SMILES : c12c(N=Nc3c(S(=O)(=O)O[Ca]4)cc(C)cc3)c(O)c(C(=O)O4)cc1cccc2

CHEM : 2-Naphthalenecarboxylic acid, 3-hydroxy-4-[(4-methyl-2-sulfophenyl)az

o]-, calcium salt (1:1)

MOL FOR: C18 H12 N2 O6 S1 Ca1

MOL WT : 424.44

--------------------------- KOCWIN v2.00 Results ---------------------------

Koc Estimate from MCI:

---------------------

First Order Molecular Connectivity Index ........... : 13.365

Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 7.5670

Fragment Correction(s):

1 Azo (-N=N-) ......................... : -0.6475

1 Misc (C=O) Group (aliphatic attach).... : -1.6047

1 Miscellaneous S(=O) group .......... : -1.2980

1 Aromatic Hydroxy (aromatic-OH) ....... : -0.0966

Corrected Log Koc .................................. : 3.9202

Estimated Koc: 8321 L/kg <===========

Validity criteria fulfilled:
not specified
Conclusions:
The soil adsorption coefficient i.e Koc value of Calcium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate was estimated to be 8321 L/kg (log Koc=3.9202) by means of MCI method (at 25 deg C). This Koc value indicates that the substance Calcium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2-naphthoate has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.
Executive summary:

KOCWIN model of Estimation Programs Interface was used to predict the soil adsorption coefficient i.e Koc value of test chemical Calcium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate (CAS No. 5281 -04 -9). The soil adsorption coefficient i.e Koc value of Calcium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate was estimated to be 8321 L/kg (log Koc=3.9202) by means of MCI method (at 25 deg C). This Koc value indicates that the substance Calcium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2-naphthoate has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

Description of key information

KOCWIN model of Estimation Programs Interface (2018) was used to predict the soil adsorption coefficient i.e Koc value of test chemical Calcium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate (CAS No. 5281 -04 -9). The soil adsorption coefficient i.e Koc value of Calcium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate was estimated to be 8321 L/kg (log Koc=3.9202) by means of MCI method (at 25 deg C). This Koc value indicates that the substance Calcium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2-naphthoate has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

Key value for chemical safety assessment

Koc at 20 °C:
8 321

Additional information

Predicted data for the target compound Calcium 3-hydroxy-4-[(4-methyl-2-sulphonatophenyl)azo]-2-naphthoate (CAS No. 5281-04-9) and various supporting weight of evidence studies for its structurally and functionally similar read across substance were reviewed for the adsorption end point which are summarized as below:

 

KOCWIN model of Estimation Programs Interface was used to predict the soil adsorption coefficient i.e Koc value of test chemical Calcium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate (CAS No. 5281 -04 -9). The soil adsorption coefficient i.e Koc value of Calcium 3 -hydroxy-4 -[(4 -methyl-2 -sulfonatophenyl)diazenyl]-2 -naphthoate was estimated to be 8321 L/kg (log Koc=3.9202) by means of MCI method (at 25 deg C).

 

In a supporting weight of evidence study from experimental study report (2016), the adsorption coefficient Koc in soil and in sewage sludge of test chemical was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals. The solutions of the test substance and reference substances were prepared in appropriate solvents. A test item solution was prepared by accurately weighing 50mg of test item and diluted with mobile phase up to 100ml. Thus, the test solution concentration was 500mg/l. The pH of test substance was 6.24. Each of the reference substance and test substance were analysed by HPLC at 210 nm. After equilibration of the HPLC system, Urea was injected first, the reference substances were injected in duplicate, followed by the test chemical solution in duplicate. Reference substances were injected again after test sample, no change in retention time of reference substances was observed. Retention time tR were measured, averaged and the decimal logarithms of the capacity factors k were calculated. The graph was plotted between log Koc versus log k(Annex - 2).The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and therewith, log Koc of the test substance was determined from its measured capacity factor. The reference substances were chosen according to structural similarity with the test substance and calibration graph was prepared. The reference substances were Phenol, Aniline, Nitrobenzene, naphthalene, Phenanthrene and DDT having Koc value ranging from 1.32 to 5.63. The Log Koc value of test chemical was determined to be 3.679 ± 0.076 at 25°C.

 

For the test chemical, the adsorption coefficient Koc in soil and in sewage sludge of test chemical was determined by the Reverse Phase High Performance Liquid Chromatographic method according to OECD Guideline No. 121 for testing of Chemicals (Experimental study report, 2016). The solutions of the test substance and reference substances were prepared in appropriate solvents. A test item solution was prepared by accurately weighing 50mg of test item and diluted with mobile phase up to 100ml. Thus, the test solution concentration was 500mg/l. The pH of test substance was 7.33. Each of the reference substance and test substance were analysed by HPLC at 210 nm. After equilibration of the HPLC system, Urea was injected first, the reference substances were injected in duplicate, followed by the test chemical solution in duplicate. Reference substances were injected again after test sample, no change in retention time of reference substances was observed. Retention time tR were measured, averaged and the decimal logarithms of the capacity factors k were calculated. The graph was plotted between log Koc versus log k(Annex - 2).The linear regression parameter of the relationship log Koc vs log k were also calculated from the data obtained with calibration samples and therewith, log Koc of the test substance was determined from its measured capacity factor. The reference substances were chosen according to estimated Koc range of the test substance and generalized calibration graph was prepared. The reference substances were Phenol, 4 methyl aniline, nitrobenzene, toluene, Ethylbenzene, Phenanthrene, and DDT having Koc value ranging from 1.32 to 5.63. The Log Koc value of test chemical was determined to be 3.6 ± 0.06 at 25°C.

 

On the basis of above overall results for target chemical Calcium 3-hydroxy-4-[(4-methyl-2-sulphonatophenyl)azo]-2-naphthoate (from modelling databases,2017), it can be concluded that the log Koc value of test substance Calcium 3-hydroxy-4-[(4-methyl-2-sulphonatophenyl)azo]-2-naphthoate was estimated to be3.9202indicating that the test chemical Calcium 3 -hydroxy-4 -[(4 -methyl-2 -sulphonatophenyl)azo]-2 -naphthoate has a strong sorption to soil and sediment and therefore have negligible to slow migration potential to ground water.

 

[LogKoc: 3.9202]