Registration Dossier

Administrative data

Endpoint:
phototransformation in air
Type of information:
calculation (if not (Q)SAR)
Remarks:
Migrated phrase: estimated by calculation
Adequacy of study:
key study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Data calculated from several sources, limitations in reporting but considered reliable with restriction

Data source

Reference
Reference Type:
review article or handbook
Title:
Kinetics and mechanisms of gas-phase reactions with the hydroxyl radical with organic compounds under atmospheric conditions.
Author:
Atkinson, R.
Year:
1985
Bibliographic source:
Chem. Rev. 85, 61-201.

Materials and methods

Principles of method if other than guideline:
Measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. The author applied a least squares analysis of degradation rate constants to calculate a preferred value.
Calculated half life based on a rate constant of 8.41E-15 cm3.molecule.sec-1, OH radical concentration 10-5 molecules.cm-3, as specified in the TGD.

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Estimation method (if used):
Calculated half life based on a rate constant of 8.41E-15 cm3.molecule.sec-1, OH-radical concentration 5.105 molecules.cm-3, as specified in the TGD.
Details on test conditions:
at 298K

Results and discussion

Dissipation half-life of parent compound
DT50:
1 906 d

Applicant's summary and conclusion

Conclusions:
The half life of methane has been estimated to be 1906 days based on a recommended reaction rate with hydroxyl radicals and the concentration of hydroxyl radicals recommended in the Technical Guidance Document (2003).
Executive summary:

Measured data from author and other investigators were quality assessed and then used to develop rate constants for different chemicals. Therefore, this value represents a valid rate constant for methane based on all valid studies at the time of publication.