Decahydro-2-naphthyl acetate

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:

09 August 2000 - 06 September 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method C.4-E (Determination of the "Ready" Biodegradability - Closed Bottle Test)

Deviations:

no

Qualifier:

equivalent or similar to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

sewage, domestic (adaptation not specified)

Details on inoculum:

- Source: Secondary effluent of a domestic sewage treatment plant (STP Odenthal, Germany)
- Preparation of inoculum for exposure: Separation of coarse particles by filtration and aeration of mineral medium plus innoculum for 5 days

Duration of test (contact time):

28 d

Initial conc.:

2.7 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Remarks:

expressed as percentage of theoretical oxygen demand (ThOD) or chemical oxygen (COD)

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral medium
- Test temperature: 20 ± 1°C
- Suspended solids concentration: 5 mL/L
- Continuous darkness: yes

TEST SYSTEM
- Number of culture flasks/concentration: 10 vessels per test item treatment, procedure control, inoculum blank and toxicity control
- Test performed in closed vessels due to significant volatility of test substance: Tested in completely full, closed bottles

SAMPLING
- Sampling frequency: 7, 14, 21 and 28 days

CONTROL AND BLANK SYSTEM
- Inoculum blank: A measured volume of mineral medium containing only inoculum
- Toxicity control: Toxic effects of the test substance are determined in a toxicity control flask (containing test substance, reference substance and inoculum)
- Other: Procedure control - In order to check the procedure, the reference chemical sodium benzoate is tested by setting up 2 flasks in parallel to the normal tests runs

Reference substance:

benzoic acid, sodium salt

Remarks:

Initial concentration: 2.9 mg reference compound/L

Test performance:

The toxicity control demonstrated that the used concentrations of the test substance did not show toxic effects to bacteria.

Parameter:

% degradation (O2 consumption)

Value:

5

Sampling time:

7 d

Parameter:

% degradation (O2 consumption)

Value:

6

Sampling time:

14 d

Parameter:

% degradation (O2 consumption)

Value:

8

Sampling time:

21 d

Key result

Parameter:

% degradation (O2 consumption)

Value:

9

Sampling time:

28 d

Key result

Parameter:

ThOD

Value:

2 608 mg O2/g test mat.

Results with reference substance:

The reference compound showed 68, 76, 82 and 86% degradation after 7, 14, 21 and 28 days, respectively. The ThOD of the reference substance was determined to be 1665 mg O2/g reference substance.

Validity criteria fulfilled:

yes

Remarks:

Reference item reached 76% degradation after 14 days; no toxicity was observed in the toxicity control; difference in extremes of replicate values was <20%; oxygen depletion in the inoculum blank did not exceed 1.5 mg/L dissolved oxygen after 28 days.

Interpretation of results:

not readily biodegradable

Conclusions:

The test item is not readily biodegradable, as 9% degradation of the test item was observed within 28 days.

Executive summary:

The ready biodegradability of the test item was determined based on oxygen consumption in a 28 -day closed bottle study. Secondary effluent of a domestic sewage treatment plant was used as the inoculum and the test item was tested at 2.7 mg/L, alongside a reference substance, inoculum blank and toxicity control. 9% degradation of the test item was observed within 28 days, therefore the test item is considered as not readily biodegradable. The study is reliable without restriction (Klimisch 1) as it was GLP-compliant and was performed according to EU Method C.4 -E and OECD Guideline 301D.

Description of key information

9% degradation of the test item was observed within 28 days, therefore the test item is not readily biodegradable. 

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Additional information

The ready biodegradability of the test item was determined based on oxygen consumption in a 28 -day closed bottle study (2000). Secondary effluent of a domestic sewage treatment plant was used as the inoculum and the test item was tested at 2.7 mg/L, alongside a reference substance, inoculum blank and toxicity control. 9% degradation of the test item was observed within 28 days, therefore the test item is considered as not readily biodegradable. The study is reliable without restriction (Klimisch 1) as it was GLP-compliant and was performed according to EU Method C.4 -E and OECD Guideline 301D.