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Adsorption / desorption

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Reference
Endpoint:
adsorption / desorption
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
Reference:
Composition 0
Qualifier:
according to
Guideline:
other: Modelling 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
Test material information:
Composition 1
Specific details on test material used for the study:
- Name of test material (as cited in study report): 4-amino-3-methylbenzenesulfonic acid
- Molecular formula: C7H9NO3S
- Molecular weight: 187.218 g/mol
-Smiles: S(c1cc(c(N)cc1)C)(O)(=O)=O
- InChI: 1S/C7H9NO3S/c1-5-4-6(12(9,10)11)2-3-7(5)8/h2-4H,8H2,1H3,(H,9,10,11)
- Substance type: Organic
- Physical state: Solid
Radiolabelling:
not specified
Test temperature:
25 deg.C
Analytical monitoring:
not specified
Key result
Type:
Koc
Value:
10 L/kg
Temp.:
25 °C
Remarks on result:
other: Log Koc=1(estimated by MCI method)

KOCWIN Program (v2.00) Results:

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

SMILES : O=S(=O)(O)c(ccc(N)c1C)c1

CHEM : Benzenesulfonic acid, 4-amino-3-methyl-

MOL FOR: C7 H9 N1 O3 S1

Koc may be sensitive to pH!

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

Koc Estimate from MCI:

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

First Order Molecular Connectivity Index ........... : 5.410

Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 3.4199

Fragment Correction(s):

1 Nitrogen to non-fused aromatic ring ... : -0.5225

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

Corrected Log Koc .................................. : 0.8974

Over Correction Adjustment to Lower Limit Log Koc ... : 1.0000

Estimated Koc: 10 L/kg

Validity criteria fulfilled:
not specified
Conclusions:
The Soil Adsorption Coefficient i.e Koc value of 4-amino-3-methylbenzenesulfonic acid was estimated using EPI suite KOCWIN Program (v2.00) as Koc 10 L/kg (log Koc = 1) by means of MCI method at 25 deg.C. This Koc value indicates that the substance 4-amino-3-methylbenzenesulfonic acid has a negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.
Executive summary:

The Soil Adsorption Coefficient i.e Koc value of 4-amino-3-methylbenzenesulfonic acid  was estimated using EPI suite  KOCWIN Program (v2.00) as Koc 10 L/kg (log Koc = 1)  by means of MCI method at 25 deg.C. This Koc value indicates that the substance 4-amino-3-methylbenzenesulfonic acid  has a negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

Description of key information

The Soil Adsorption Coefficient i.e Koc value of 4-amino-3-methylbenzenesulfonic acid  was estimated using EPI suite  KOCWIN Program (v2.00) as Koc 10 L/kg (log Koc = 1)  by means of MCI method at 25 deg.C. This Koc value indicates that the substance 4-amino-3-methylbenzenesulfonic acid  has a negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

Key value for chemical safety assessment

Koc at 20 °C:
10

Additional information

Three different studies from validated predicted databases and experimental study for adsorption endpoint of target chemical 4-amino-3-methylbenzenesulfonic acid (Cas no. 98-33-9) with relevant read across which is structurally similar to target chemical are summarized as followed:

 

First study from prediction report using EPI suite KOCWIN model (v2.00) indicate the Soil Adsorption Coefficient i.e Koc value of 4-amino-3-methylbenzenesulfonic acid was estimated as Koc 10 L/kg (log Koc = 1) by means of MCI method at 25 deg.C. This Koc value indicates that the substance 4-amino-3-methylbenzenesulfonic acid has negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

 

Whereas Chemspider - ACD/PhysChem Suite prediction model and Scifinder database indicate the soil adsorption coefficient i.e Koc value of test substance 44-amino-3-methylbenzenesulfonic acid was estimated to be 1 (Log koc-0) at pH 1-10 (including pH range 5.5 and 7.4 from Chemspider data source)and temperature 25 deg.C. This Koc value at all range of pH condition indicates that the substance 4-amino-3-methylbenzenesulfonic acid has negligible sorption to soil and sediment and therefore have rapid migration potential to groundwater.

 Above both predicted values of target chemical are further supported by experimental study of read across chemical 4-aminobenzenesulfonic acid (also reported as Sulfanilic acid; CAS no. 121-57-3) which suggest the adsorption coefficient (Koc) of substance Sulfanilic acid was found to be 10 using a structure estimation method based on molecular connectivity indices.This Koc value suggests that sulfanilic acid is expected to have very high mobility in soil.(HSDB database;2017)

All values for adsorption is in the range of log Koc 1-0 (L/kg or dimensionless) which gives common conclusion as target chemical 4-amino-3-methylbenzenesulfonic acid (Cas no. 98-33-9) has high mobility in soil/sediment compartment.

[LogKoc: 1.0]