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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:
2018-06-14 - 2018-08-02
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2018
Report Date:
2018

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid
Specific details on test material used for the study:
Name trans-2,3-Dibromo-2-Butene-1,4-Diol
Batch no. 1088
Appearance White crystalline powder
Composition trans-2,3-Dibromo-2-Butene-1,4-Diol 100%
CAS No. 3234-02-4
EINECS-No. 221-779-5
Molecular formula HOCH2C(Br)=C(Br)CH2OH
Molecular weight 245.91 g/mol
Purity 100% by GC

Study design

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic, adapted
Details on inoculum:
Specification
Activated sludge from a biologic sewage treatment plant was used as inoculum. The cho-sen plant treats mostly domestic sewage.
Source and Pre-Treatment of inoculum
Source
The sludge was taken from the activation basin of the sewage treatment plant, In den Seewiesen, 67480 Edenkoben.
Date of collection: 29. Jun. 2018, batch no: 20180629.
Pre-Treatment
The sludge was filtrated, washed with test medium (2x) and re-suspended in test medium. It was then aerated until use. The dry matter was determined to contain 4060 mg of sus-pended solids/L.
Duration of test (contact time):
28 d
Initial test substance concentrationopen allclose all
Initial conc.:
102.9 mg/L
Based on:
test mat.
Initial conc.:
102.3 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
CO2 evolution
Reference substance
Reference substance:
aniline

Results and discussion

% Degradationopen allclose all
Key result
Parameter:
% degradation (CO2 evolution)
Value:
0.7
Sampling time:
2 d
Key result
Parameter:
% degradation (CO2 evolution)
Value:
2.9
Sampling time:
9 d
Key result
Parameter:
% degradation (CO2 evolution)
Value:
3.3
Sampling time:
14 d
Key result
Parameter:
% degradation (CO2 evolution)
Value:
6.4
Sampling time:
23 d
Key result
Parameter:
% degradation (CO2 evolution)
Value:
5.3
Sampling time:
29 d

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
Degradation behaviour of positive control and toxicity control was normal. Abiotic degradation was not observed. 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 consid-ered as toxic towards the inoculum. As degradation in the toxicity flask was 38.7 % after 14 days, the test item can be stated as “not toxic towards the inoculum in a concentration of 102.3 mg/L”.
Ready biodegradability is defined in the guidelines as degradation surpassing 60% within 10 days after reaching a level of 10 %. Therefore, the test item trans-2,3-Dibromo-2-Butene-1,4-Diol can be considered as “not readily biodegradable”. Degradation missed 60 % within 28 days, though. Therefore, the test item is considered as “not ultimately biodegradable within 28 days”, as well)
Executive summary:

The test item trans-2,3-Dibromo-2-Butene-1,4-Diolwas tested using a concentration of nominally 20 mg organic carbon/Ltrans-2,3-Dibromo-2-Butene-1,4-Diolin test medium following OECD 301B and EU-Method C.4-C.

 

Aniline was chosen as positive control.

Activated sludge was used as inoculum (concentration in the test 25.0 mg dry matter/L). The test was left running for 28 days.

All validity criteria were met. Degradation of the positive control surpassed the pass level of 60 % after 9 days.

 

The following data were determined for the test item trans-2,3-Dibromo-2-Butene-1,4-Diol:

10-day-window:                                                                                                             not detected
degradation at the end of 10-day-window                                                                             none
degradation at the end of the test                                                                                              5 %

pass level following guideline:       60 % at the end of 10-day-window for pure substances

                                                                        respective 60 % at the end of the test for mixtures

Therefore, when applying the 10-day-window, the test itemtrans-2,3-Dibromo-2-Butene-1,4-Diol is not readily biodegradable following OECD 301B and EU C.4-C respectively. As degradation missed 60% in the course of the test,trans-2,3-Dibromo-2-Butene-1,4-Diolis considered as not ultimately biodegradable,within 28 days.