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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

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Diss Factsheets

Environmental fate & pathways

Phototransformation in air

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Administrative data

Link to relevant study record(s)

Reference
Endpoint:
phototransformation in air
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
key study
Study period:
Not applicable
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
accepted calculation method
Qualifier:
no guideline followed
Principles of method if other than guideline:
An estimation of the atmospheric oxidization rate of the test substance was performed using the Atkinson method.
GLP compliance:
no
Remarks:
Not applicable
Light source:
other: not applicable
Key result
DT50:
2.066 h
Remarks on result:
not measured/tested
Remarks:
values is calculated based on AOP rate estimation
Key result
DT50:
3.2 h
Remarks on result:
not measured/tested
Remarks:
Value is re-calculated based on restrictiverate estimation
Reaction with:
OH radicals
Rate constant:
0 cm³ molecule-1 s-1
Remarks on result:
other: Value is calculated based on AOP rate estimation
Reaction with:
OH radicals
Rate constant:
0 cm³ molecule-1 s-1
Remarks on result:
other: Value is calculated based on restrictive rate estimation
Transformation products:
not measured

- AOP rate estimation: Overall OH Rate Constant = 62.1353 E-12 cm3/molecule-sec; Half-life = 0.172 days (12-hr day; 1.5E6 OH/cm3); Half-life = 2.066 Hrs

- Restrictive Rate estimation: Based on the well experienced chemical reactivity in the sequence amine-ester/amide-carbamate it is supposed, that the fragments taken to represent the carbamate group in the estimation calculation show a too fast reactivity agents and have got the following results (calculated with OH-Radicals/cm3 and a 12 hours day):

K(min) 40.4 E-12 cm3/molecule-sec;

Halflife (max): 3.2 hours

The estimated halflife (Atkinson method) of the test substance in the atmosphere (by hydroxyl radical oxidation) is therefore between 2 and 3 hours.

Validity criteria fulfilled:
not applicable
Conclusions:
Based on the results of the AOP and restrictive rate estimation, the estimated half-life (Atkinson method) of the test substance in the atmosphere (by hydroxyl radical oxidation) is between 2.1 and 3.2 hours.
Executive summary:

An estimation of the atmospheric oxidization rate based on an AOP rate estimation resulted in an overall OH rate constant of 62.1353E-12 cm3/molecule-sec, with a 0.172 days half-life (equivalent to 2.066 hours). A more restrictive estimation, not accounting for unknown structural elements in the AOP estimation, the recalculated rate constant was at 40.4E-12 cm3/molecule-sec, with a half-life of 3.2 hours. The rate for photolytic degradation in the atmosphere was estimated with the AOP program V1.51 using the Atkinson method. Based on the calculations, the estimated half-life of the test substance in the atmosphere (by hydroxyl radical oxidation) was between 2.1 and 3.2 hours. A half-life value of 3.2 hours was used for the CSA.

Description of key information

All available data was assessed and the study representing the worst-case effects is included here as key result. The results can be considered worst-case and are selected for the CSA.

Estimated half-life (Atkinson method) = 3.2 hours, in the atmosphere by hydroxyl radical oxidation, Stamm 1994

Key value for chemical safety assessment

Half-life in air:
3.2 h
Degradation rate constant with OH radicals:
0 cm³ molecule-1 s-1

Additional information

An estimation of the atmospheric oxidization rate based on an AOP rate estimation resulted in an overall OH rate constant of 62.1353E-12 cm3/molecule-sec, with a 0.172 days half-life (equivalent to 2.066 hours). A more restrictive estimation, not accounting for unknown structural elements in the AOP estimation, the recalculated rate constant was at 40.4E-12 cm3/molecule-sec, with a half-life of 3.2 hours. The rate for photolytic degradation in the atmosphere was estimated with the AOP program V1.51 using the Atkinson method. Based on the calculations, the estimated half-life of the test substance in the atmosphere (by hydroxyl radical oxidation) was between 2.1 and 3.2 hours. A half-life value of 3.2 hours was used for the CSA.