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Adsorption / desorption

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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 test material: Pyrazine-2-carboxylic acid
- Molecular formula: C5H4N2O2
- Molecular weight: 124.099 g/mol
- Substance type: organic
- Physical state: solid
- Smiles: c1ncc(C(=O)O)nc1
- InChI: 1S/C5H4N2O2/c8-5(9)4-3-6-1-2-7-4/h1-3H,(H,8,9)
Radiolabelling:
not specified
Test temperature:
25 deg.C
Analytical monitoring:
not specified
Key result
Type:
Koc
Value:
4.192 L/kg
Temp.:
25 °C
Remarks on result:
other: Log Koc = 0.622 (estimated by MCI method)
Transformation products:
not specified

KOCWIN Program (v2.00) Results:

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

SMILES : c1nccnc1C(=O)O

CHEM : Pyrazinoic acid

MOL FOR: C5 H4 N2 O2

Koc may be sensitive to pH!

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

Koc Estimate from MCI:

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

First Order Molecular Connectivity Index ........... : 4.305

Non-Corrected Log Koc (0.5213 MCI + 0.60) .......... : 2.8438

Fragment Correction(s):

* Organic Acid (-CO-OH) ............... : -1.6249

1 Aromatic ring with 2 nitrogens ....... : -0.5964

Corrected Log Koc .................................. : 0.6225

Estimated Koc: 4.192 L/kg <===========

Validity criteria fulfilled:
not specified
Conclusions:
The soil adsorption coefficient i.e Koc value of Pyrazine-2-carboxylic acid was estimated to be 4.192 L/kg (log Koc=0.6225) by means of MCI method (at 25 deg C). This Koc value indicates that the substance Pyrazine-2-carboxylic acid has a negligible sorption to soil and sediment and therefore have rapid 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 Pyrazine-2-carboxylic acid (CAS No. 98 -97 -5). The soil adsorption coefficient i.e Koc value of Pyrazine-2-carboxylic acid was estimated to be 4.192 L/kg (log Koc=0.6225)  by means of MCI method (at 25 deg C). This Koc value indicates that the substance Pyrazine-2-carboxylic acid has a negligible sorption to soil and sediment and therefore have rapid 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 Pyrazine-2-carboxylic acid (CAS No. 98 -97 -5). The soil adsorption coefficient i.e Koc value of Pyrazine-2-carboxylic acid was estimated to be 4.192 L/kg (log Koc=0.6225)  by means of MCI method (at 25 deg C). This Koc value indicates that the substance Pyrazine-2-carboxylic acid has a negligible sorption to soil and sediment and therefore have rapid migration potential to ground water.

Key value for chemical safety assessment

Koc at 20 °C:
4.192

Additional information

Various predicted data for the target compound Pyrazine-2-carboxylic acid (CAS No. 98-97-5) were reviewed for the adsorption end point which are summarized as below:

 

In a prediction done using theKOCWIN Program(v2.00) of Estimation Programs Interface (EPI Suite, 2017), the soil adsorption coefficient i.e Koc value of Pyrazine-2-carboxylic acid was estimated to be 4.192 L/kg (log Koc=0.6225) by means of MCI method (at 25 deg C).

 

The Soil Adsorption Coefficient i.e Koc value of test substance Pyrazine-2-carboxylic acid was estimated using Adsorption Coefficient module (v12.1.0.50374) program as Koc 2.76, 3.89, 3.95, 3.20, 1.09 and 1 at pH 0, 1, 2, 3, 4 and at pH range 5-14 respectively (log Koc ranges from 0.0 ± 1.0 to 0.6 ± 1.0)(ACD (Advanced Chemistry Development)/I-Lab predictive module, 2017).

 

In another prediction done by using ChemSpider Database (2017), the Soil Adsorption Coefficient i.e Koc value of test substance Pyrazine-2-carboxylic acid (CAS no. 98 -97 -5) was estimated. The adsorption coefficient (Koc) value of substance Pyrazine-2-carboxylic acid was estimated to be 1 (Log Koc = 0) at pH 5.5 and 7.4, respectively.

 

Additional soil adsorption coefficient i.e Koc value of test chemical Pyrazine-2-carboxylic acid (CAS No. 98 -97 -5)was estimated using the SciFinder database (American Chemical Society (ACS), 2017). The soil adsorption coefficient i.e Koc value of Pyrazine-2-carboxylic acid was estimated to be 10.1, 10.2, 8.28, 2.82 and 1 at pH 1, 2, 3, 4 and 5-10, respectively (log Koc = 0 to 1) (at 25 deg C).

 

On the basis of above overall results for target chemical Pyrazine-2 -carboxylic acid (from EPI suite, ACD labs,ChemSpider and SciFinder database, 2017), it can be concluded that the Koc value of test substance Pyrazine-2-carboxylic acid ranges from 1 –10.2 indicating that the test chemical Pyrazine-2-carboxylic acid has a negligible sorption to soil and sediment and therefore have rapid migration potential to ground water.

[LogKoc: 0.6225]