Nitrapyrin

Phototransformation in air

Administrative data

Endpoint:

phototransformation in air

Type of information:

calculation (if not (Q)SAR)

Remarks:

Migrated phrase: estimated by calculation

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Data source

Reference

Reference Type:

other: model calculation report

Title:

Unnamed

Year:

2014

Report date:

2014

Materials and methods

Principles of method if other than guideline:

Calculation using SRC AOP v1.92

GLP compliance:

no

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

Study design

Estimation method (if used):

PHOTOCHEMICAL REACTION WITH OH RADICALS
- Concentration of OH radicals: 500000 molecules/cm3
- Degradation rate constant: 0.0350 E-12cm3/molecules*s
- Computer programme: SRC AOP v1.92
- Other: assuming a 24-hour day

Results and discussion

Dissipation half-life of parent compound

DT50:

458 d

Test condition:

The substance is within the applicability domain of the models

Any other information on results incl. tables

AOP Program (v1.92) Results:

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

SMILES : n(c(ccc1)C(CL)(CL)CL)c1CL

CHEM :

MOL FOR: C6 H3 CL4 N1

MOL WT : 230.91

------------------- SUMMARY (AOP v1.92): HYDROXYL RADICALS (25 deg C) --------

Hydrogen Abstraction = 0.0000 E-12 cm3/molecule-sec

Reaction with N, S and -OH = 0.0000 E-12 cm3/molecule-sec

Addition to Triple Bonds = 0.0000 E-12 cm3/molecule-sec

Addition to Olefinic Bonds = 0.0000 E-12 cm3/molecule-sec

**Addition to Aromatic Rings = 0.0350 E-12 cm3/molecule-sec

Addition to Fused Rings = 0.0000 E-12 cm3/molecule-sec

OVERALL OH Rate Constant = 0.0350 E-12 cm3/molecule-sec

HALF-LIFE = 458.007 Days (24-hr day; 0.5E6 OH/cm3)

 

** Designates Estimation(s) Using ASSUMED Value(s)

------------------- SUMMARY (AOP v1.91): OZONE REACTION (25 deg C) -----------

****** NO OZONE REACTION ESTIMATION ******

(ONLY Olefins and Acetylenes are Estimated)

Experimental Database: NO Structure Matches

Fraction sorbed to airborne particulates (phi):

0.000115 (Junge-Pankow, Mackay avg)

6.08E-005 (Koa method)

Note: the sorbed fraction may be resistant to atmospheric oxidation

Applicant's summary and conclusion

Executive summary:

The phototransformation in air was calculated using EPIsuite AOPWIN program. Using the respective half-life was determined to be 458 days. After evaporation or exposure to the air, the product will be slowly degraded by photochemical processes.

QPRF:AOPWIN

 

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	Phototransformation in air
		Dependent variable	Hydroxyl reaction rate constant (cm^3/molecule*sec)
3.2		Model or submodel name	AOPWIN
		Model version	1.92
		Reference to QMRF	QMRF: Estimation of Atmospheric Degradation Using AOPWIN v1.92 (EPI Suite v4.11): Hydroxyl Radical Reaction
		Predicted value (model result)	See “Results and discussion”
		Input for prediction	- Chemical structure via CAS number or SMILES
		Descriptor values	- Structure fragments
3.3	Algorithm (OECD Principle 2)	Domain (On-Line AOPWIN User’s Guide): As the complete training sets for AOPWIN's estimation methodology are not available, describing a precise estimation domain for this methodology is not possible. There is no information on the number of instances of fragments in the training dataset.
		If the substance is a member of one of the following chemical classes, the substance is probablywithinthe applicability domain of the model (based on information by other authors, e.g. Posthumus and Slooff, 2001): alkanes, haloalkanes, alkenes, haloalkenes, polyenes, terpenes, alkynes, aldehydes, ketones, alcohols, glycols, ethers, esters, epoxides, thiols, thioethers, aliphatic amines, hydrazines, nitrites, nitrates, nitriles, P-containing organics, aromatic compounds (alkylbenzenes, halobenzenes, phenols, PAHs, styrene, methoxybenzene, aniline, nitrobenzene, biphenyl, dibenzofurans, dibenzodioxins)		Fulfilled
		The substance isnotwithinthe applicability domain of the model if it is a perhalogenated alkanes.		The substance is not a perhalogenated alkane
		Substance is a secondary, tertiary and heterocyclic amine. Estimated valueshighly uncertain.		The substance is not a   secondary, tertiary and heterocyclic amine
3.4	The uncertainty of the prediction (OECD principle 4)	- n = 667 - correlation coefficient r^2= 0.963 - standard deviation = 0.218 - absolute mean error = 0.127 - 90% of the estimated rate constants within a factor of two of the experimental data - 95% of the estimated rate constants within a factor of three of the experimental data
3.5	The chemical mechanisms according to the model underpinning the predicted result (OECD principle 5)	Reaction rate constants for hydroxyl radicals are the summation of the following mechanisms: (1) Hydrogen abstraction (2) Reaction with specific nitrogen and sulphur fragments and reaction with hydroxyl (OH) fragments such as alcohols and phenols (3) Addition to triple bonds (4) Addition to olefinic bonds (5) Addition to aromatic rings (6) Addition to fused rings The model works according to the group contribution method which uses fragments and the corresponding reaction values to estimate the reaction rate constant of a given substance.

 

References

- R Posthumus and W Slooff (2001). Implementation of QSARs in ecotoxicological risk assessments. RIVM report 601516 003. Online: http://rivm.openrepository.com/rivm/bitstream/10029/9559/1/601516003.pdf

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