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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:
14 February 2017 - 15 March 2017
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2017
Report date:
2017

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to guideline
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Qualifier:
according to guideline
Guideline:
EU Method C.4-C (Determination of the "Ready" Biodegradability - Carbon Dioxide Evolution Test)
Qualifier:
according to guideline
Guideline:
EPA OPPTS 835.3110 (Ready Biodegradability)
GLP compliance:
yes (incl. QA statement)

Test material

Constituent 1
Chemical structure
Reference substance name:
2-(2H-benzotriazol-2-yl)-4-tert-butylphenol
EC Number:
221-574-0
EC Name:
2-(2H-benzotriazol-2-yl)-4-tert-butylphenol
Cas Number:
3147-76-0
Molecular formula:
C16H17N3O
IUPAC Name:
2-(5-tert-Butyl-2-hydroxyphenyl)benzotriazole
Test material form:
solid: particulate/powder
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- Source and lot/batch No.of test material: 02002IX3
- Expiration date of the lot/batch: 25 August 2017

STABILITY AND STORAGE CONDITIONS OF TEST MATERIAL
- Storage condition of test material: room temperature in the dark

Study design

Inoculum or test system:
activated sludge (adaptation not specified)
Details on inoculum:
A mixed population of activated sewage sludge micro-organisms was obtained on 13 February 2017.
Duration of test (contact time):
28 d
Initial test substance concentration
Initial conc.:
10 mg/L
Based on:
DOC
Reference substance
Reference substance:
benzoic acid, sodium salt

Results and discussion

Preliminary study:
Information provided by the Sponsor indicated that the test item was insoluble in water. Therefore preliminary solubility/dispersibility work was performed in order to determine the most suitable method of preparation.
% Degradation
Parameter:
% degradation (CO2 evolution)
Value:
0
Sampling time:
28 d
Details on results:
Statistical analysis of the Day 29 IC values for the control and test item vessels showed there were no statistically significant differences (Pā‰„ 0.05) between the control and the test item.
The toxicity control attained 34% biodegradation after 14 and 28 days thereby confirming that the test item did not exhibit an inhibitory effect on the sewage treatment micro-organisms used in the test.
Sodium benzoate attained 84% biodegradation after 14 days and 83% biodegradation after 28 days thereby confirming the suitability of the inoculum and test conditions. The slight decrease in biodegradation between Days 14 and 28 was considered to be due to sampling/analytical variation.

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
under test conditions no biodegradation observed
Conclusions:
The test item attained 0% biodegradation after 28 days and therefore cannot be considered to be readily biodegradable under the strict terms and conditions of OECD Guideline No. 301B.
The test item was therefore considered not to have a toxic effect on the sewage sludge micro-organisms used in the study and this was confirmed by the toxicity control results.