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Environmental fate & pathways

Biodegradation in water: screening tests

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Administrative data

Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1998
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Guideline study without detailed documentation

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1998
Report Date:
1998

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Deviations:
not specified
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
No data indicated in the report.

Study design

Oxygen conditions:
not specified
Inoculum or test system:
not specified
Duration of test (contact time):
28 d
Parameter followed for biodegradation estimation
Parameter followed for biodegradation estimation:
O2 consumption
Remarks:
- BOD (mg O2 consummed by mg of substance)
Details on study design:
The report refers to the protocol described in the annexe C.4-E of the Directive 92/69/CEE. This protocol is in accordance with the OECD guideline N°301D adopted 17/07/1992.
Reference substance
Reference substance:
other: Sodium benzoate

Results and discussion

Test performance:
Validity criteria of the test:
- The difference between the extreme values ​​of the replicates obtained in the test serie (Serie 2) is less than 20%;
- The percentage of degradation of the reference material the serie of inoculum control (Serie 4) is greater than 60% in 14 days;
- The degradation of th ereference material in the serie of inhibition control (serie 3) is greater than 25% during the first 14 days: the degradation of reference substance was not inhibited by the presence of the test substance;
- The loss of oxygen in the blank serie (Serie 1) containing the inoculum did not exceed 1.5mg/ l dissolved O2 after 28 days;
- The residual oxygen concentration in the test flasks was always greater than 0.5mg/ l throughout the test period.
% Degradationopen allclose all
Parameter:
% degradation (O2 consumption)
Remarks:
- expressed in: mg O2 consumed by mg of substance
Value:
0
Sampling time:
0 d
Remarks on result:
other: Milieu + inoculum + substance
Parameter:
% degradation (O2 consumption)
Remarks:
- expressed in: mg O2 consumed by mg of substance
Value:
23
Sampling time:
7 d
Remarks on result:
other: Milieu + inoculum + substance
Parameter:
% degradation (O2 consumption)
Remarks:
- expressed in: mg O2 consumed by mg of substance
Value:
35
Sampling time:
14 d
Remarks on result:
other: Milieu + inoculum + substance
Parameter:
% degradation (O2 consumption)
Remarks:
- expressed in: mg O2 consumed by mg of substance
Value:
72
Sampling time:
21 d
Remarks on result:
other: Milieu + inoculum + substance
Parameter:
% degradation (O2 consumption)
Remarks:
- expressed in: mg O2 consumed by mg of substance
Value:
78
Sampling time:
28 d
Remarks on result:
other: Milieu + inoculum + substance

BOD5 / COD results

BOD5 / COD
Parameter:
COD
Value:
1.11 other: mgO2/mg test. mat.

Any other information on results incl. tables

Tables with the complete results:

COD ou DThO  (mgO2/mg)

 COD ou DThO   (mgO2/mg)
 Dibromo-1,6-hexane  1.11
 Sodium benzoate  1.67
 Serie 3  1.34

BOD specific ( mg O2 consumed/ mg test. mat.)

 Time (days)  0  7 14  21  28 
 Serie 2 (substance)  0.00 0.25  0.39  0.81  0.87 
 Serie 3 (inhibition control) 0.00  0.60  0.75  0.98  1.07 
 Serie 4 (reference) 0.00  1.33  1.38  1.33  1.44 

Biodegradability (mean)

 Time (days)  0 14  21  28 
 Serie 2 (substance) 0% 23% 35% 72%  78% 
 Serie 3 (inhibition control) 0% 45%  56% 74% 80% 
 Serie 4 (reference) 0% 80%  83%  80% 

86% 

Applicant's summary and conclusion

Validity criteria fulfilled:
yes
Interpretation of results:
readily biodegradable, but failing 10-day window
Conclusions:
Under the conditions of the test performed under 301D OECD guideline, the biodegradation percentage of dibromo-1,6-hexane was 78% in 28 days (end of testing). Within the 10 days windows, it was about 32%. Within 14 days to the commencement of the testing, the percentage of degradation has reached 35%.