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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
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 test material (IUPAC name): 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid
- Molecular formula: C11H11NO4S
- Molecular weight: 253.2769 g/mol
- Smiles notation: CNc1ccc2cc(cc(c2c1)O)S(=O)(=O)O
- InChl: 1S/C11H11NO4S/c1-12-8-3-2-7-4-9(17(14,15)16)6-11(13)10(7)5-8/h2-6,12-13H,1H3,(H,14,15,16)
- Substance type: Organic
- Physical state: Solid
Radiolabelling:
not specified
Test temperature:
25 deg.C
Analytical monitoring:
not specified
Key result
Type:
Koc
Value:
260.6 L/kg
Temp.:
25 °C
Remarks on result:
other: Log Koc= 2.4160 (estimated by MCI method)
Transformation products:
not specified

KOCWIN Program (v2.00) Results:

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

SMILES : O=S(=O)(O)c(cc(O)c(c1ccc2NC)c2)c1

CHEM : 2-Naphthalenesulfonic acid, 4-hydroxy-6-(methylamino)-

MOL FOR: C11 H11 N1 O4 S1

Koc may be sensitive to pH!

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

Koc Estimate from MCI:

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

First Order Molecular Connectivity Index ........... : 7.914

Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 4.7254

Fragment Correction(s):

1 Nitrogen to Carbon (aliphatic) (-N-C).. : -0.2127

1 Sulfonic acid (-S(=O)-OH) ............. : -2.0000

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

Corrected Log Koc .................................. : 2.4160

Estimated Koc: 260.6 L/kg <===========

Validity criteria fulfilled:
not specified
Conclusions:
The soil adsorption coefficient i.e Koc value of 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid was estimated to be 260.6 L/kg (log Koc=2.4160) by means of MCI method (at 25 deg C). This Koc value indicates that the substance 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.
Executive summary:

KOCWIN model (v2.00) of Estimation Programs Interface (EPI Suite, 2017) was used to predict the soil adsorption coefficient i.e Koc value of test chemical 4 -hydroxy-6 -(methylamino)naphtha lene-2 -sulfonic acid (CAS No. 6259 -53 -6). The soil adsorption coefficient i.e Koc value of 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid was estimated to be 260.6 L/kg (log Koc=2.4160)  by means of MCI method (at 25 deg C). This Koc value indicates that the substance 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.

Description of key information

KOCWIN model (v2.00) of Estimation Programs Interface (EPI Suite, 2017) was used to predict the soil adsorption coefficient i.e Koc value of test chemical 4 -hydroxy-6 -(methylamino)naphtha lene-2 -sulfonic acid (CAS No. 6259 -53 -6). The soil adsorption coefficient i.e Koc value of 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid was estimated to be 260.6 L/kg (log Koc=2.4160)  by means of MCI method (at 25 deg C). This Koc value indicates that the substance 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.

Key value for chemical safety assessment

Koc at 20 °C:
260.6

Additional information

Various predicted data for the target compound 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No. 6259-53-6) and supporting weight of evidence study for its structurally similar read across substance were reviewed for the adsorption end point which are summarized as below:

 

In aprediction done using theKOCWIN Program(v2.00) of Estimation Programs Interface (EPI Suite, 2017) was used to predict the soil adsorption coefficient i.e Koc value of test chemical 4 -hydroxy-6 -(methylamino)naphtha lene-2 -sulfonic acid (CAS No. 6259 -53 -6). The soil adsorption coefficient i.e Koc value of 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid was estimated to be 260.6 L/kg (log Koc=2.4160)  by means of MCI method (at 25 deg C). This Koc value indicates that the substance 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.

 

The Soil Adsorption Coefficient i.e Koc value of test substance 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS no. 6259 -53 -6) was estimated using Adsorption Coefficient module (v12.1.0.50374) program as Koc 1 (log Koc = 0) at pH range 1-14 respectively(ACD (Advanced Chemistry Development)/I-Lab predictive module, 2017). This Koc value indicates that the test substance 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid has a negligible sorption to soil and therefore have rapid migration potential to groundwater.

 

In an another prediction done by using ChemSpider Database (2017),the Soil Adsorption Coefficient i.e Koc value of test substance 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS no. 6259 -53 -6) was estimated. The adsorption coefficient (Koc) value of test substance 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid was estimated to be 1 (Log Koc = 0 at both pH 5.5 and 7.4, respectively. This Koc value indicates that the test substance 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid has a negligible sorption to soil and therefore have rapid migration potential to groundwater.

 

Additional soil adsorption coefficient i.e Koc value of test chemical4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (CAS No. 6259 -53 -6)was estimated using the SciFinder database (American Chemical Society (ACS), 2017).The soil adsorption coefficient i.e Koc value of 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid was estimated to be 1 (log Koc = 0) (at 25 deg C). This Koc value indicates that the substance 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid has a negligible sorption to soil and sediment and therefore have rapid migration potential to ground water.

 

In a supporting weight of evidence study from experimental study report (Sustainability Support Services (Europe) AB, Report no. UERL/PC/010-03, 2017) for the read across chemical aluminium, 6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonic acid complex (CAS No. 15790 -07 -5), the adsorption coefficient Koc in soil and in sewage sludge of read across chemical aluminium, 6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonic acid complex 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 3 mg of test item and diluted with methanol: water (2:3) phase up to 25ml. Thus, the test solution concentration was 120 mg/l. The pH of test substance was 5.44. 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 functional similarity with the test substance and calibration graph prepared. The reference substances were 2-nitrophenol, nitrobenzene, 4-nitrobenzamide, N, N-dimethylbenzamide and Nmethylbenzamide having Koc value ranging from 1.3 to 2.47. The Log Koc value of chemical aluminium, 6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonic acid complex was determined to be 2.1368 ± 0.0018 at 25°C. This log Koc value indicates that the substance aluminium, 6-hydroxy-5-[(4-sulfophenyl)azo]-2-naphthalenesulfonic acid complex has a low sorption to soil and sediment and therefore have moderate migration potential to ground water.

 

On the basis of above overall results for target chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid (from EPI suite, ACD labs,ChemSpider and Scifinder,2017) and for its read across substance from experimental UERL study report, it can be concluded that the Koc value of test substance 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid ranges from 1–260.6, indicating that the test chemical 4-hydroxy-6-(methylamino)naphthalene-2-sulfonic acid has a negligible to low sorption to soil and sediment and therefore have rapid to moderate migration potential to ground water.

[LogKoc: 2.416]