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Environmental fate & pathways

Biodegradation in water: screening tests

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Reference
Endpoint:
biodegradation in water: ready biodegradability
Type of information:
experimental study
Adequacy of study:
key study
Study period:
January 2002 - February 2002
Reliability:
2 (reliable with restrictions)
Qualifier:
according to
Guideline:
OECD Guideline 301 D (Ready Biodegradability: Closed Bottle Test)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Specific details on test material used for the study:
SOURCE OF TEST MATERIAL
- lot No.of test material: 110100
- Expiration date of the lot/batch: assumed stable for the duration of the studys under the storage condition
- Purity: 99.9%

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

Oxygen conditions:
aerobic
Inoculum or test system:
activated sludge, domestic (adaptation not specified)
Details on inoculum:
- Source of activated sludge: sludge of city sewage treatment plant from Kurume central treatment center (japan)
- Storage conditions: aerobic condition
- Activated sludge preparation: the sampling sludge was filtered through a filter paper and a filter was used as activated sludge.

Duration of test (contact time):
28 d
Initial conc.:
7.09 mg/L
Based on:
test mat.
Parameter followed for biodegradation estimation:
O2 consumption
Details on study design:
TEST CONDITIONS
- Composition of medium: mineral medium was performed following the OECD guideline
- Test temperature: 20 +/- 1°C
- pH adjusted: /no
- Culturing apparatus: incubator (SANYO)
- Test performed in closed vessels due to significant volatility of test substance: yes


Reference substance:
benzoic acid, sodium salt
Key result
Parameter:
% degradation (O2 consumption)
Value:
0
Sampling time:
28 d
Key result
Parameter:
% degradation (test mat. analysis)
Value:
2
Sampling time:
28 d
Details on results:
The degradation of the test item was determined both by measurement of the dissolved oxygen (DO) and by analytical monitoring of the test item.
The percentage degradation using the BOD was 0% at 28 days.
The percentage degradation using the analytical monitoring (GC) of the test item was 2 % at 28 days

details of analytical results and the percentage degradation at all time points are given in the table 1 and 2 respectively (in "any other information on results including tables"

Table 1 : Analytical result of the test solutions

 

 

Water + test item

Sludge + test item

Theoretical amount

1

2

1

2

 

BOD

mgO2/L

-

-

0

0

5.60

Residual amount and % residue of the test item

mg

0.713

0.714

0.686

0.708

0.709

%

101

101

97

100

-

Table 2 : Percentage degradation

Method

Percentage degradation %

The value in () is a mean value

7 days

14 days

21 days

28 days

BOD

3

0

0

0

1

0

0

0

(2)

(0)

(0)

(0)

GC

-

-

-

4

-

-

-

1

 

 

 

(2)

Validity criteria fulfilled:
yes
Interpretation of results:
not readily biodegradable
Conclusions:
The test item was not biodegraded by microorganisms under the tests conditions.
Executive summary:

The determination of the "ready" biodegradability of the test item was performed using the closed bottle test according to OECD guideline No. 301 D, 1992.

The test substance was tested at 0.709 mg/l, corresponding to theoretical amount of 5.60 mg dissolved oxygen/l.

The study consisted of 29 bottles:

- 11 control blanks (no test substance),

- 12 test bottles (Sludge + Test item),

- 4 reference solutions (Sludge + sodium benzoate)

- 2 test solution blanks (Water + Test item),

Test duration was 28 days. The relative biodegradation values calculated from both the measurements of the biologic Oxygen Demand (BOD) and the test item concentration performed during the test period revealed no significant biodegradation of the test item.

The percentage degradation using the BOD was 0% at 28 days.

The percentage degradation using the analytical monitoring (GC) of the test item was 2 % at 28 days.

Since all criteria for acceptability of the test were met, this study was considered to be valid.

The test item was not readily biodegradable by microorganisms under the tests conditions.

Description of key information

The Hexafluoro-1,3-butadiene was not readily biodegradable under the conditions of the closed bottle test (OECD guideline No. 301 D and GLP compliant ).

Key value for chemical safety assessment

Biodegradation in water:
under test conditions no biodegradation observed

Additional information

One reliable study is available for the Hexafluoro-1,3-butadiene for this endpoint.

The "ready" biodegrability of the test item Hexafluoro-1,3-butadiene was determined in one GLP-compliant study performed in accordance with the OECD guideline No. 301D, without deviations. The study is considered as reliable (Klimisch 1) and is selected as a key study for the endpoint.

The determination of the "ready" biodegradability of the test item was performed using the closed bottle test

The test substance was tested at 0.709 mg/l, corresponding to theoretical amount of 5.60 mg dissolved oxygen/l.

The study consisted of 29 bottles:

- 11 control blanks (no test substance),

- 12 test bottles (Sludge + Test item),

- 4 reference solutions (Sludge + sodium benzoate),

- 2 test solution blanks (Water + Test item),

Test duration was 28 days. The relative biodegradation values calculated from both the measurements of the biologic Oxygen Demand (BOD) and the test item concentration performed during the test period revealed no significant biodegradation of the test item.

The percentage degradation using the BOD was 0% at 28 days.

The percentage degradation using the analytical monitoring (GC) of the test item was 2 % at 28 days

 

Since all criteria for acceptability of the test were met, this study was considered to be valid.

 

The test item was not readily biodegradable by microorganisms under the tests conditions.