Graphene

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 Oct 2019 to 20 Feb 2020

Reliability:

1 (reliable without restriction)

Reason / purpose for cross-reference:

reference to same study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

not mentioned

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

natural water: freshwater

Remarks:

Environmental Culture (surface water)

Details on inoculum:

- Initial cell/biomass concentration: 200 CFU/mL

Duration of test (contact time):

28 d

Initial conc.:

3.4 mg/L

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Test temperature: 23 +/- 1C
- pH: 7.2 (begin) – 7.5 (end)
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: One-liter bottles
- Number of culture flasks/concentration: 2 x test item, 2 x control
- Measuring equipment: The bottles were closed with Oxi-Top® measuring heads and the measuring system was activated.

Reference substance:

acetic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

ca. 0

Sampling time:

28 d

Parameter:

COD

Value:

33 mg O2/g test mat.

Parameter:

COD

Value:

8.25 mg O2/g test mat.

Results with reference substance:

67.4 % degradation after 28 days.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The degradation rate of the test material did not reach 60% within the 10-day window or after 28 days. Therefore, the test item is considered to be not readily biodegradable.

Executive summary:

Study design

The ready biodegradability of the test material was determined according to OECD TG 301 D for a period of 28 days under GLP requirements.

The test item was directly added to the sample jars by weight with no additional solvent or dispersants. The OECD 301D biodegradation method measures the oxygen consumed from a test solution incorporating a bacterial inoculum and the test item. The chemical oxygen demand (COD) for the test item was determined. Based on COD, percent degradation of the test item was calculated.

 

Results

The determined biodegradability of the test item was 0% by % COD. The test item did not achieve the requirements for Ready Biodegradability by the OECD 301D standard for degradation of 60% COD within a 10-day window of the test time frame.

 

Conclusion

The test item is considered to be not readily biodegradable.

Description of key information

Ready biodegradation, OECD 301D, GLP, not readily biodegradable

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

Ready biodegradability:

The ready biodegradability of the test material was determined according to OECD Guideline 301 D for a period of 28 days under GLP requirements.

The test item was directly added to the sample jars by weight with no additional solvent or dispersants. The OECD 301D biodegradation method measures the oxygen consumed from a test solution incorporating a bacterial inoculum and the test item. The chemical oxygen demand (COD) for the test item was determined. Based on COD, percent degradation of the test item was calculated.

 

The determined biodegradability of the test item was 0% by % ThCOD. The test item did not achieve the requirements for Ready Biodegradability by the OECD 301D standard for degradation of 60% COD within a 10-day window of the test timeframe.