Nitrapyrin

Adsorption / desorption

Administrative data

Endpoint:

adsorption / desorption

Remarks:

adsorption

Type of information:

(Q)SAR

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Accepted calculation method, substance within applicability domain.

Justification for type of information:

QSAR prediction: migrated from IUCLID 5.6

Data source

Reference

Reference 1

Reference Type:

other: EPIWIN calculation

Title:

Unnamed

Year:

2014

Report date:

2014

Reference 2

Reference Type:

other: Estimation software

Title:

Estimation Programs Interface Suite for Microsoft Windows, v4.11

Author:

US EPA

Year:

2012

Bibliographic source:

United States Environmental Protection Agency, Washington, DC, USA; November 2012

Materials and methods

Principles of method if other than guideline:

KOCWIN (v2.00): estimation using estimated or experimentally derived log Kow

GLP compliance:

no

Type of method:

other: QSAR estimation: KOCWIN v2.00: Koc estimate from log Kow

Test material

Test material information

Constituent 1

Reference substance name:

Nitrapyrin

EC Number:

217-682-2

EC Name:

Nitrapyrin

Cas Number:

1929-82-4

Molecular formula:

C6H3Cl4N

IUPAC Name:

2-chloro-6-(trichloromethyl)pyridine

Constituent 2

Reference substance name:

Reference substance 001

Study design

Test temperature:

25 °C

Batch equilibrium or other method

Computational methods:

- Other: log Kow used for estimation:
estimated by KOCWIN

Results and discussion

Adsorption coefficient

Adsorption coefficient 1

Type:

Koc

Value:

972

Temp.:

25 °C

Remarks on result:

other: The substance is within the applicability domain of the model.

Adsorption coefficient 2

Type:

log Koc

Value:

2.988

Temp.:

25 °C

Remarks on result:

other: The substance is within the applicability domain of the model.

Any other information on results incl. tables

Koc Estimate from Log Kow

Log Kow (experimental DB) : 3.41

Non-Corrected Log Koc (0.55313 logKow + 0.9251) : 2.8113

Fragment Correction(s): 1 Pyridine ring: 0.1764

Corrected Log Koc : 2.9876

Estimated Koc: 972 L/kg

Applicant's summary and conclusion

Executive summary:

The soil adsorption coefficient (Koc) was calculated using EPIsuite KOCWIN program. Using the Kow method the Koc was calculated to be 972 L/kg and Log Koc to be 2.9876 respectively. Accordingly, adsorption to solid soil phase is not expected.

QPRF: KOCWIN v2.00 (18 Nov. 2013)

 

1.	Substance	See “Test material identity”
2.	General information
2.1	Date of QPRF	See “Data Source (Reference)”
2.2	QPRF author and contact details	See “Data Source (Reference)”
3.	Prediction
3.1	Endpoint (OECD Principle 1)	Endpoint	Adsorption to solid phase of soils etc.
		Dependent variable	Organic carbon normalised adsorption coefficient (Koc)
3.2	Algorithm (OECD Principle 2)	Model or submodel name	KOCWIN
		Model version	v. 2.00
		Reference to QMRF	QMRF: Estimation of Soil Adsorption Coefficient using KOCWIN v2.00 (EPI Suite v4.11): Estimation using log Kow
		Predicted value (model result)	See “Results and discussion”
		Input for prediction	- Chemical structure via CAS number or SMILES - log Kow (for log Kow method; optional)
		Descriptor values	- Chemical structure - Correction factors
3.3	Applicability domain (OECD principle 3)	Domains:
		1) Molecular weight (range of test data set: 32.04 to 665.02 g/mol; On-Line KOCWIN User’s Guide, Ch. 6.2.4 Domain)	Substance within range (230.9067g/mol)
		2) log Kow (range of test data set: -2.11 to 8.12; On-Line KOCWIN User’s Guide, Appendices E & F)	Substance within range (3.41)
		3) Correction factors: Number of instances of the identified correction factor does not exceed the maximum number as listed in Appendix D (On-Line KOCWIN User’s Guide)	fulfilled.
3.4	The uncertainty of the prediction (OECD principle 4)	Nonpolar compounds: n = 68; r^2=0.478, average dev. = 0.371 Polar compounds: n = 447, r²=0.855, std. dev. = 0.396, average dev. = 0.307
3.5	The chemical mechanisms according to the model underpinning the predicted result (OECD principle 5)	Adsorption is caused by temporary (reversible) or permanent bonding between the substance and a surface (e.g. due to van der Waals interactions, hydrogen bonding to hydroxyl groups, ionic interactions, covalent bonding, etc.). The organic carbon normalized adsorption coefficient (Koc) is the ratio of a substance concentration sorbed in the organic matter component of soil or sediment to that in the aqueous phase at equilibrium. Estimation using log Kow: The model is based on the high correlation of log Kow and the adsorption potential.

 

References

- US EPA (2012). On-Line KOCWIN User’s Guide.

- Meylan, W., P.H. Howard and R.S. Boethling. 1992. Molecular topology/fragment contribution method for predicting soil sorption coefficients. Environ. Sci. Technol. 26: 1560-1567.

 

 

Assessment of estimation domain (molecular weight, fragments, correction factors):

Model:	KOCWIN v2.00	MCI & Log Kow method
Substance:	nitrapyrin
CAS-#:	1929-82-4
SMILES:	Clc1cccc(n1)C(Cl)(Cl)Cl
Molecular weight (g/mol):	230,9067
Log Kow (experimental data):	3.41	Reference:	EPISUITE - KOWWIN data base match
	Molecular weight (g/mol)				log Kow
	Minimum	Maximum	Average		Minimum	Maximum
Training set	32.04	665.02	224.4		-2.11	8.12
Validation set	73.14	504.12	277.8		-5.98	8.68
Assessment of molecular weight	Molecular weight within range of training and validation set.
Assessment of log Kow (only relevant for log Kow method)	Log Kow within range of training and validation set.
Appendix D. MCI & Log Kow Correction Factors for 447 Compound Training Set
Correction Factor Descriptor	Coefficient for Molecular Connectivity Index (MCI) Regression Methodology		Coefficient for log Kow Regression Methodology	Occurrence		No. of instances of each bond found for the current substance
	(new model)	Remark		(number of compounds	(max per structure)
Pyridine ring	-0.308035		0.176372	12	1	1