Registration Dossier

Environmental fate & pathways

Biodegradation in water: screening tests

Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2012-01-20 - 2012-05-24
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2012
Report Date:
2012

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): (1R)-1-[(4R,4aR,8aS)-2,6-bis(4-chlorophenyl)tetrahydro[1,3]dioxino[5,4-d][1,3]dioxin-4-yl]ethane-1,2-diol
- Appearance: white powder
- Expiration date of the lot/batch: December 2012
- Storage condition of test material: room temperature (20 ± 5°C); keep away from humidity

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, non-adapted
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
20 mg/L
Based on:
DOC
Initial conc.:
35.6 mg/L
Based on:
test mat.

Results and discussion

% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
2
Sampling time:
28 d
Details on results:
All validity criteria were met.
Degradation behaviour of positive control (61% after 9 d) and toxicity control (46% after 14 d) was normal. Abiotic degradation was less than 1 %. Both replicates of the test item showed very good correspondence.
If degradation in the toxicity flask is below 25% after 14 days, the test item can be considered as toxic towards the inoculum. As degradation in the toxicity flask was 46% after 14 days, the test item can be stated as “not toxic towards the inoculum in a concentration of 35.6 mg/L”.
Ready degradability is defined in the guidelines as degradation surpassing 60% within 10 days after reaching a level of 10%. Therefore, the test item cannot be considered as “readily biodegradable”.
Because of a poor calibration, the measured IC concentration and the calculated degradation of the positive control and in the toxicity flask on day 23 were slightly higher than on day 29. This can be stated as uncritical for the outcome of the study. No observations were made which might cause doubts concerning the validity of the study outcome. The result of the test can be considered valid

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
The test item is not readily biodegradable - regardless of the 10-day-window - following OECD 301B/EU C.4-C, as degradation at the end of the test was only 2 %.