2-benzylheptanol

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:

2022-06-16 to 2022-08-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 F (Ready Biodegradability: Manometric Respirometry Test)

Version / remarks:

1992

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Activated sludge from the sewage plant at Hildesheim, Germany. It receives predominantly municipal sewage.
- The activated sludge was washed twice with chlorine free tap water. After the second washing the settled sludge was resuspended in mineral salts medium and was maintained in an aerobic condition by aeration with CO2 free air until test start (3 days) at test temperature.
- The amount of inoculum used to initiate inoculation was 4.76 mL/L (25.0 mg/L dw).

Duration of test (contact time):

60 d

Initial conc.:

18 mg/L

Based on:

test mat.

Initial conc.:

52.9 mg/L

Based on:

ThOD

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

PRE-TREATMENT
- The test item was applied via a stock solution in silicone oil. The stock solution was prepared by weighing out of 9.0 g/L test item in a measuring flask and adding approx. 10 mL of silicone oil.
- The stock solution was shaken until the test item was fully dissolved.
- Upon visual checking, the final test solution was clear. 496.5 µL was pipetted into the brown glass bottles.


TEST CONDITIONS
- Composition of medium: Mineral salts medium according to OECD 301 F
- Test temperature: Nominal: 20 - 24 ± 1 °C; Actual: 22.1 – 22.5 °C
- Photoperiod: Dark

TEST SYSTEM
- Culturing apparatus: Sealed bottles
- Number of culture flasks: 4 for the inoculum control, 4for the inoculum control with silicone oil, 2 for the functional control, 1 for the functional control with silicone oil, 3 for the test item replicates, 3 for the test item replicates with silicone oil, 1 for the toxicity control, 1 for the toxicity control with silicone oil.
- Method used to create aerobic conditions: Headspace of air
- Measuring equipment: OxiTop OC110 controller with software Achat OC, WTW

SAMPLING
- Sampling frequency: daily

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

79

Sampling time:

28 d

Remarks on result:

other: Test item solved in silicone oil for application due to low solubility in water

Parameter:

% degradation (O2 consumption)

Value:

86

Sampling time:

60 d

Remarks on result:

other: Test item solved in silicone oil for application due to low solubility in water

Details on results:

Degradation kinetics (%):
-Day 8: Rep1 15%, Rep2 15%, Rep3 14%
-Day 14: Rep1 67%, Rep2 61%, Rep3 57%
-Day 28: Rep1 88%, Rep2 77%, Rep3 72%


Toxicity control:
- Day 2: 27%
- Day 14: 82%
- Day 28: 91%

Results with reference substance:

Biodegradation of the Functional Control:
- Day 2: 52%
- Day 14: 81%
- Day 28: 83%

Validity criteria fulfilled:

yes

Interpretation of results:

readily biodegradable

Conclusions:

The study showed that the test item is readily biodegradable. The test item fulfilled the 10-d window criterion (started at day 7) and reached its pass level (60%) at day 14.

Executive summary:

The present study was conducted in order to evaluate the biodegradability of the test item by measuring its percentage of biodegradation with inoculum in a period of 28 days. The test method was performed following the OECD Test Guideline 301F and GLP.

The test item concentration was 18 mg/L. It was solved in silicone oil for the application due to its low water solubility. Benzoic acid was used as reference substance in the functional control as well as in the toxicity control. The 10-d window was fulfilled. After the 28-d period the biodegradation of the test item was calculated to be 79%. Therefore, it is regarded as readily biodegradable. 

Description of key information

Readily biodegradable: 79% after 28 days (OECD 301F)

 

Key value for chemical safety assessment

Biodegradation in water:

readily biodegradable

Type of water:

freshwater

Additional information

The present study was conducted in order to evaluate the biodegradability of the test item by measuring its percentage of biodegradation with inoculum in aperiod of 28 days. The test method was performed following the OECD Test Guideline 301F and GLP.

The test item concentration was 18 mg/L. It was solved in silicone oil for the application due to its low water solubility. Benzoic acid was used as reference substance in the functional control as well as in the toxicity control. The 10-d window was fulfilled. After the 28-d period the biodegradation of the test item was calculated to be 79%. Therefore, it is regarded as readily biodegradable.