Registration Dossier

Administrative data

Endpoint:
phototransformation in water
Type of information:
experimental study
Adequacy of study:
key study
Study period:
from 14 June 1993 to 27 may 1994
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1994
Report Date:
1994

Materials and methods

Study type:
direct photolysis
Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Aqueous solutions of atrazine and an actinometer were subjected to artificial light from a xenon arc lamp while under constant temperature at 25°C. Solutions of atrazine and actinometer were also maintained in the dark to act as controls. At six time-points subsamples were removed from the test solutions and analysed via HPLC to monitor any decrease in test substance concentration. The use of an actinometer was necessary to calculate the quantum yield
GLP compliance:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Batch n. C103330. CH20512
Purity: 99.9%
Expiry May 1996
Appaerance: white powder
Storage conditions: room temperature

Study design

Radiolabelling:
no
Analytical method:
high-performance liquid chromatography
Light source:
Xenon lamp
Light spectrum: wavelength in nm:
290 - 500
Duration of test at given test condition
Duration:
10 d
Temp.:
25 °C
Initial conc. measured:
15.323 other: µg/ml

Results and discussion

Spectrum of substance
Parameter:
epsilon 295 nm
Value:
85.1 L/(mol cm)
% Degradation
% Degr.:
39
Sampling time:
5 d
Test condition:
preliminary test
Transformation products:
not measured

Any other information on results incl. tables

The quantum yield for direct photodegradation was established as 1.0585 x 10^-4.

the calculated rate costant of atrazine has need estimated as 0.08732 days^-1

Applicant's summary and conclusion

Validity criteria fulfilled:
not specified
Conclusions:
Atrazine has been found to photodegrade in the Suntest apparatus with a half-life time of 7.9 days. The quantum yield for direct photodegradation was established as 1.0585 x 10^-4. Using published tables of irradiance values, an environmental half-life time for atrazine of 29 days was obtained for surface waters at latitude 40 - 50°N.