1,6-dibromohexane

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:

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

Guideline:

OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)

Deviations:

not specified

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

Dibromo-1,6-hexane

IUPAC Name:

Dibromo-1,6-hexane

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.

% Degradation

% Degradation 1

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

% Degradation 2

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

% Degradation 3

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

% Degradation 4

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

% Degradation 5

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	7	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%.