4-trans-Pentyl-[1,1-bicyclohexyl]-4-on

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:

1992-02-26 to 1992-03-25

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

1981

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of activated sludge: 1 L from the total effluent of a sludge plant and 1 L reflux from an activated sludge plant (Klärwerk Neuenfelde, Hamburg)
- Pretreatment: The activated sludge was filtered, discarding the first 200 mL. Further, 100 g of a standard soil (a mixture of humus and loamy soil from the region of Speyer) were dispersed in 1000 mL of demineralized water and then filtered, again discarding the first 200 mL of the filtrate. 100 mL of each filtrate were mixed for the composite inoculum.

Duration of test (contact time):

28 d

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral nutrient solution according to OECD 301D
- Test temperature: 20 °C
- Aeration of dilution water: Yes
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: 300 mL BOD-bottles
- Number of culture flasks/concentration: 3
- Measuring equipment: 0X1 530 with a EO 200-electrode (Wissenschaftlich-Technische Werkstätten GmbH, 8120 Weilheim, Germany)
- Test performed in open system: No

CONTROL AND BLANK SYSTEM
- Control series: distilled water with nutrient solutions without inoculum
- Blind series: distilled water with nutrient solutions with inoculum
- Reference series: a solution of sodium-n-dodecylsulfate (SDS) with nutrient solutions and inoculum
- Inhibition series: a solution of the test substance and SDS with nutrient solutions and inoculum

SAMPLING
- Sampling frequency: The oxygen content in the aqueous test solutions was determined electrochemically on the following dates: 0, 5, 15 and 28 days.

Reference substance:

other: sodium-n-dodecylsulfate

Key result

Parameter:

% degradation (O2 consumption)

Value:

4

Sampling time:

28 d

Details on results:

For the test substance the following results were obtained: 1 % after 5 days; 2 % after 15 days; 4 % after 28 days. Therefore, the test substance can be described as not ready biodegradable under the test conditions.
BOD (28 days) = 3.08 g O2/g test material
Inhibition Test: The difference of the O2-Consumption of the reference series and the O2-Consumption of the test item has a low negative value. Thus, the test substance has a weak inhibitory effect.

Results with reference substance:

For the reference substance (as active substance (AS)) the following figures were obtained: 36 % after 5 days, 65 % after 15 days, 87 % after 28 days.
A biodegradability of > 60 % already after 28 days indicates a fully active inoculum and the experimental conditions of the degradation experiments are considered to be correct in the sense of the Guideline.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The degradation rate of the test material was 4 % after 28 days. The test item is therefore not ready biodegradable.

Executive summary:

The test item was investigated for its ready biodegradability in a Closed Bottle Test over a period of 28 days according to OECD TG 301D.The biodegradation was followed by the oxygen depletion of the microorganisms during exposure. As a reference item sodium-n-dodecylsulfate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control. After correction for the mean biochemical oxygen demand of the inoculum controls the percentage of the test item reached 4 % after 28 days of incubation. The reference item was sufficiently degraded to a mean of 87 % after 28 days of incubation, thus confirming the suitability of the used activated sludge inoculum. Based on the result of the inhibition test, the test item can be assumed to be have a weak inhibitory effect on the activated sludge microorganisms. The degradation rate of the test material did not reach 60 % within the 10-day window and after 28 days of incubation. The test item is therefore not ready biodegradable (reference 5.2.1-1).

 

Description of key information

The degradation rate of the test material was 4 % after 28 days. The test item is therefore not ready biodegradable (reference 5.2.1-1).

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

The test item was investigated for its ready biodegradability in a Closed Bottle Test over a period of 28 days according to OECD TG 301D.The biodegradation was followed by the oxygen depletion of the microorganisms during exposure. As a reference item sodium-n-dodecylsulfate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control. After correction for the mean biochemical oxygen demand of the inoculum controls the percentage of the test item reached 4 % after 28 days of incubation. The reference item was sufficiently degraded to a mean of 87 % after 28 days of incubation, thus confirming the suitability of the used activated sludge inoculum. Based on the result of the inhibition test, the test item can be assumed to be have a weak inhibitory effect on the activated sludge microorganisms. The degradation rate of the test material did not reach 60 % within the 10-day window and after 28 days of incubation. The test item is therefore not ready biodegradable (reference 5.2.1-1).