Registration Dossier

Administrative data

Endpoint:
phototransformation in water
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1995
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1995

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
EPA Guideline Subdivision N 161-2 (Photodegradation Studies in Water)
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent

Study design

Light source:
sunlight
Duration of test at given test condition
Temp.:
25 °C
Initial conc. measured:
8.55 mg/L

Results and discussion

Spectrum of substanceopen allclose all
Parameter:
max epsilon
Value:
7 432
Parameter:
epsilon 295 nm
Value:
6 081
% Degradationopen allclose all
% Degr.:
48.5
Sampling time:
8 h
Test condition:
Direct photolysis
Test condition:
Indirect photolysis
Dissipation half-life of parent compound
DT50:
8.4 h
Test condition:
pH 7
Transformation products:
yes

Any other information on results incl. tables


14C-PBO was found to rapidly photolyze in an aqueous buffer at pH 7 and  25 °C 

when exposed to natural sunlight. Within 36 hours of exposure to  sunlight less 

than 10 % of the total radioactivity in the exposed sample  was 14C-PBO.  

The calculated t1/2  of the aqueous photolysis rate of PBO  was 8.4 hours of 

sunlight and the photolysis of PBO followed first order  kinetic. Two major 

degradates were observed at concentrations greater  than 10 % of the total 

radioactivity. One degradate was identified as an  alcohol degradate of PBO, 

the other was identified as the corresponding  aldehyde of the alcohol degradate.

Applicant's summary and conclusion

Conclusions:
The substance was found to rapidly photolyze in an aqueous buffer at pH 7 and  25 °C when exposed to natural sunlight.
DT50 = 8.4 hours at pH 7