2,2'-(vinylenedi-p-phenylene)bis[5-methylbenzoxazole]

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

guideline study with acceptable restrictions

Justification for type of information:

The read across approach is detailed in section 13.

Reason / purpose for cross-reference:

read-across source

Qualifier:

according to guideline

Guideline:

other: DIN 38 409

GLP compliance:

yes

Specific details on test material used for the study:

Due to insufficient solubility, no stock solution was used.
The test specimen was weighed directly into the container batches.

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, predominantly domestic (adaptation not specified)

Details on inoculum:

- Source of inoculum/activated sludge: municipal wastewater treatment plant Frankfurt/M-Sindlingen.
- Collected sludge: 25 mg/l dry weight.
- Pre-treatment: 7 days under stirring, in mineral nutrient solution.

Duration of test (contact time):

28 d

Initial conc.:

137 mg/L

Based on:

test mat.

Initial conc.:

335 mg/L

Based on:

COD

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: the composition of the reaction medium corresponded to the medium described in the EEC Directive 84/449.
- Test temperature: 22 ± 1 °C
- Vessels: Erlenmeyer flasks.

Parameter:

% degradation (O2 consumption)

Value:

0

Sampling time:

28 d

Details on results:

Test item resulted to be not biodegradable under the conditions of the experiment.

Oxygen consumption - test item

Day	Determination 1		Determination 2		Determination 3		Mean decomposition (%)
	Theoretical oxygen		Theoretical oxygen		Theoretical oxygen
	mg/l (O2) 350.95		mg/l (O2) 350.95		mg/l (O2) 350.95
	Oxygen consumption	Decomposition (%)	Oxygen consumption	Decomposition (%)	Oxygen consumption	Decomposition (%)
3	0.0	0	0.00	0	-	-	0
7	1..3	0	0.00	0	-	-	0
10	2.0	1	0.00	0	-	-	1
14	3.6	1	0.00	0	-	-	1
17	4.6	0	0.00	0	-	-	0
21	5.7	0	0.00	0	-	-	0
24	5.9	0	0.00	0	-	-	0
28	6.9	0	0.00	0	-	-	0

The third determination was not used for the evaluation because of occurrence of error.

Oxygen consumption - blank

Day	Determination 1	Determination 2	Determination 3	Mean mg/l (O2)
	Oxygen consumption mg/l (O2)
3	0.0	0.0	0.0	0.0
7	0.0	0.0	0.0	0.0
10	0.0	0.0	0.0	0.0
14	1.8	0.0	0.0	0.6
17	6.0	0.0	4.4	3.5
21	7.5	0.0	7.8	5.1
24	9.9	0.0	11.3	7.1
28	9.9	0.0	11.3	7.1

Interpretation of results:

not readily biodegradable

Conclusions:

Not ready biodegradable

Executive summary:

The determination of the test item chemical oxygen demand (COD) was performed according to DIN guideline 38 409. Due to insufficient solubility, no stock solution was used; the test substance was weighed directly into the container batches. Organisms were collected from municipal wastewater treatment plant Frankfurt/M-Sindlingen. No biodegreadation was observed over a period of 28 days, thus, the test item resulted to be not biodegradable under the conditions of the experiment.

Conclusion

Not ready biodegradable

Description of key information

Nor readily biodegradable.

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

The substance is a fluorescent brightener, benzoxazolyl stilbene derivative. It is not expected to be ready biodegradable because of its chemical structure and the specific function. Commonly, fluorescent brighteners undergo a primary transformation, i.e. interruption of the conjugation. However, the degradation process involves more steps and takes more time.

An experiment on the determination of the chemical oxygen demand (COD) is available on a structural analogue, i.e. Similar Substance 01; the read across approach can be considered as suitable and appropriate to investigate the biodegradabiity potential of Fluorescent Brightener 002. The read across approach is detailed in section 13.

The experiment was performed according to DIN guideline 38 409. No biodegreadation was observed over a period of 28 days, confirming the expectation that the substance is not readly biodegradable.