Registration Dossier

Data platform availability banner - registered substances factsheets

Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Environmental fate & pathways

Phototransformation in air

Currently viewing:

Administrative data

Link to relevant study record(s)

Reference
Endpoint:
phototransformation in air
Type of information:
calculation (if not (Q)SAR)
Adequacy of study:
supporting 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:
The reaction of test item in the atmosphere with hydroxyl radicals has been estimated using the method of Atkinson as developed in the Atmospheric Oxidation Program.
GLP compliance:
no
Remarks:
not applicable
Light source:
other: not applicable
Key result
DT50:
2.29 h
Remarks on result:
other: Calculated based on AOP rate estimation
Reaction with:
OH radicals
Rate constant:
0 cm³ molecule-1 s-1
Remarks on result:
other: AOP Rate estimation
Transformation products:
not measured

A theoretical calculation of the potential for photo-oxidation of the test substance in the atmosphere was submitted, using the method of Atkinson (1988) and the software AOP v1.8. A rate constant of 56.05 10-12 cm³/molecule.s was calculated for reaction with OH radicals assuming a 12 hour day and OH radical concentration of 1.5 x 106 OH/cm3. This corresponded to a first-order DT50 of 0.191 days (2.29 hours). 

Validity criteria fulfilled:
not applicable
Conclusions:
The estimated half-life (Atkinson method) of the test substance in the atmosphere (by hydroxyl radical oxidation) is 2.29 hours.
Executive summary:

The rate of photolytic degradation of the test substance in the atmosphere was estimated in the AOP program V1.8 (1996) using the Atkinson method. It was assumed that the OH radical concentration was 1.5E+06 OH radicals/cm3 and the OH timeframe was 12 hours/day. Based on AOP rate estimation, the overall OH rate constant was calculated to be 5.60501E-11 cm3/molecule/sec, with a 2.290 hours half-life. Therefore, the estimated half-life of the test substance in the atmosphere (by hydroxyl radical oxidation) was 2.290 hours.

Description of key information

Estimated half-life (Atkinson method) = 2.29 hours, in the atmosphere by hydroxyl radical oxidation, Hayes 2007

Key value for chemical safety assessment

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

Additional information

There is one calculation available for this endpoint. The calculation was performed in the AOP program V1.8 using the Atkinson method. It was assumed that the OH radical concentration was 1.5E+06 OH radicals/cm3 and the OH timeframe was 12 hours/day. Based on AOP rate estimation, the overall OH rate constant was calculated to be 5.605E-11 cm3/molecule/sec, with a 2.29 hours half-life. There is no ozone reaction estimation because no structure match was found.