[No public or meaningful name is available]

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:

07 November 2022 - 07 December 2022

Reliability:

1 (reliable without restriction)

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 B (Ready Biodegradability: CO2 Evolution Test)

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, adapted

Details on inoculum:

Activated sludge from a biologic sewage treatment plant was used as inoculum. The chosen plant treats mostly domestic sewage. The sludge was taken from the activation basin of the ESN (Stadtentsorgung Neustadt) sewage treatment plant, Im Altenschemel, 67435 NW-Lachen-Speyerdorf. Date of collection: 04. Nov. 2022, batch no: E20221104.

Duration of test (contact time):

28 d

Initial conc.:

10 mg/L

Based on:

other: Organic Carbon (calculated)

Details on study design:

The test item in a mineral medium was inoculated and incubated under aerobic conditions in the dark. The amount of organic carbon in the test solution due to the inoculum was kept as low as possible compared with the amount of organic carbon due to the test item. Allowance was made for the endogenous activity of the inoculum by running parallel blanks with inoculum but without test item. A positive control was run in parallel to check the operation of the procedures. Degradation was followed by determining the carbon dioxide produced. Measurements were taken at sufficiently frequent intervals to allow the identification of the beginning and end of biodegradation.
The test lasted for 28 days.

Reference substance:

aniline

Key result

Parameter:

% degradation (CO2 evolution)

Value:

82

Sampling time:

28 d

Details on results:

Degradation at the end of 10-day-window 68 %
Degradation at the end of the test 82 %
Therefore, when applying the 10-day-window, the test item is readily biodegradable following OECD 301B and EU C.4-C respectively. Because the test item is a UVCB the 10-day-window does not have to be taken into account. As degradation reached the pass level of 60% in the course of the test, the test item is considered as readily biodegradable, within 28 days.

Results with reference substance:

Degradation of the positive control surpassed the pass level of 60 % after 7 days.

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The degradation at the end of 10-day-window was 68 % while the degradation at the end of the test (28 days) was 82 %.
Therefore, when applying the 10-day-window, the test item is readily biodegradable following OECD 301B and EU C.4-C respectively. Because the test item is a UVCB the 10-day-window does not have to be taken into account. As degradation reached the pass level of 60% in the course of the test, the test item is considered as readily biodegradable, within 28 days.

Executive summary:

The test item was tested using a concentration of nominally 10 mg organic carbon/L in test medium following OECD 301B and EU-Method C.4-C.

Aniline was chosen as positive control.

Activated sludge was used as inoculum (concentration in the test 30.0 mg dry matter/L). The test was left running for 28 days.
All validity criteria were met. Degradation of the positive control surpassed the pass level of 60 % after 7 days.

The following data were determined for the test item:
10-day-window: day 2 – 12
degradation at the end of 10-day-window 68 %
degradation at the end of the test 82 %
pass level following guideline: 60 % at the end of 10-day-window for pure substances
respective 60 % at the end of the test for mixtures.

Therefore, when applying the 10-day-window, the test item is readily biodegradable following OECD 301B and EU C.4-C respectively.
Because the test item is a UVCB the 10-day-window does not have to be taken into account. As degradation reached the pass level of 60% in the course of the test, the test item is considered as readily biodegradable, within 28 days.

Description of key information

Degradation at the end of 10-day-window 68 %
Degradation at the end of the test 82 %
Therefore, when applying the 10-day-window, the test item is readily biodegradable following OECD 301B and EU C.4-C respectively. Because the test item is a UVCB the 10-day-window does not have to be taken into account. As degradation reached the pass level of 60% in the course of the test, the test item is considered as readily biodegradable, within 28 days.

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater