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
Study period:
2011 calculated
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: The reliability rating was 2 because the data were calculated

Data source

Reference
Reference Type:
other: computer model
Title:
Unnamed
Year:
2009

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
other: computer model
Principles of method if other than guideline:
Calculated values using AOPWIN version 1.92, a subroutine of the computer program EPI Suite v4.0 (US EPA 2009).
Indirect photodegradation or atmospheric oxidation potential is based on the structure activity relationship methods developed by R. Atkinson under the following conditions:
Temperature: 25 degree C
Sensitizer: OH- radical
Concentration of sensitizer: 1.5 E+6 OH- radicals/cm3
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
SMILES notation used: CC(C1=CC=C(C(CCCCCCCCCCCC)C)C2=CC=CC=C21)CCCCCCCCCCCC and CC(C1=CC=C(C(CCCCCCCCCCCC)C)C2=CC=C(C(C)CCCCCCCCCCCC)C=C21)CCCCCCCCCCCC

The above SMILES represent possible isomers for the C38H64 and C52H92 components (i.e., major components) comprising the UVCB test substance

Study design

Light source:
sunlight

Results and discussion

Dissipation half-life of parent compoundopen allclose all
DT50:
0.81 h
Test condition:
Estimated value for C38H64 components of the submission substance
DT50:
1.31 h
Test condition:
Estimated value forC52H92 components of the submission substance
Transformation products:
not specified

Any other information on results incl. tables

see below

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Conclusions:
Degradation Half-lives: 50% after 0.81 to 1.31 hr for the major components in the submission substance
Executive summary:

Indirect photochemical degradation of the major components in the submission substance as mediated by OH-attack is estimated to have a half-life of  0.81 to 1.31 hrs based on a 12 hour sunlight day and an average OH- concentration of 1.5 x E+6 OH-/cm3.   A 12-hour day half-life value normalizes degradation to a standard day light period during which hydroxyl radicals needed for photolysis are generated in the atmosphere. Although the submission substance has the potential to degrade rapidly by OH-attack, multimedia Level III distribution modeling indicates the test substance is predicted to partition negligibly (< 0.04%) to the air compartment because it has a low vapor pressure ( < 3.4 x E-4 Pa).  Although the majority of the components in the submission substance has a relatively short atmospheric oxidation half-life (0.81 -1.31 hours), this process is unlikely to contribute significantly to the loss of test susbtance from the environment.