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
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study according to internationally accepted guideline but not GLP compliant

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2013
Report Date:
2013

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
EU Method C.6 (Degradation: Chemical Oxygen Demand)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method C.5 (Degradation: Biochemical Oxygen Demand)
Deviations:
no
Qualifier:
according to
Guideline:
other: Guidence on the Application of the CLP Criteria
Deviations:
no
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
gas under pressure: refrigerated liquefied gas
Details on test material:
Test item: Difluoro-bromo-benzene
CAS No.: 348-57-2
Batch No.: L39084N
Physical state: liquid
Colour: colourless
Active Ingredient Content (GC): 96.4 %
Total impurities (GC): 0.52%
Storage: 2-8 °C, in a tightly closed container

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, non-adapted
Details on inoculum:
250.0 ml inoculum culture with 2.0 g/l dry substance concentration was made by mixing 28.75 ml stock culture with 221.25 ml mineral medium.
Duration of test (contact time):
5 d
Initial test substance concentration
Initial conc.:
250 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
other: Pressure (The liberated carbon dioxide is absorbed by sodium hydroxide so the biological oxidation generates vacuum which is registered by the measuring heads.)
Details on study design:
This study was performed to evaluate the degradability of Difluoro Bromobenzene (CAS No. 348-57-2) in an aerobic mixed bacterial culture on the base of quotient of biochemical oxygen demand (BOD) and chemical oxygen demand (COD). The test was carried out in three steps. The degradability was calculated from the quotient of BOD5 and COD according to Guidance on the Application of the CLP Criteria.

For the tests a stock solution of test item was made by dissolving 0.294 ml test item in 2 000 ml mineral medium.
The chemical oxygen demand was determined by the standard dichromate method [2]. Three replicates were measured in the test.
The biochemical oxygen demand of test item is determined by the OxiTop® system. In this test the test solutions are inoculated with mixed aerobe bacterial culture and poured into 500 ml dark glass bottles. The vessels are closed with rubber sleeves and measuring heads. The vessels are placed into incubator at 20 ± 2 °C and continuously stirring with magnetic stirrer. The test duration is 5 days. N-Allylthiourea is added to each test vessel for inhibiting of nitrification.

Results and discussion

% Degradationopen allclose all
Parameter:
other: values of vacuum
Value:
1.8
Sampling time:
1 d
Parameter:
other: values of vacuum
Value:
3.4
Sampling time:
2 d
Parameter:
other: values of vacuum
Value:
3
Sampling time:
3 d
Parameter:
other: values of vacuum
Value:
3.7
Sampling time:
4 d
Parameter:
other: values of vacuum
Value:
4.9
Sampling time:
5 d

BOD5 / COD results

BOD5 / CODopen allclose all
Parameter:
COD
Value:
0.833 g O2/g test mat.
Parameter:
BOD5
Value:
0.041 g O2/g test mat.
Parameter:
BOD5*100/COD
Value:
4.9 other: %

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
other: not rapidly degradable
Conclusions:
The BOD5/COD ratio is less than 0.5. The result of this degradability test indicated that the test item (CAS No. 348-57-2) is not rapidly degradable in the aquatic environment.