1-fluoro-3-(trans-4-propylcyclohexyl)benzene

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:

28 JAN 2015 - 04 MAR 2015

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:

July 17, 1992

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method C.4-D (Determination of the "Ready" Biodegradability - Manometric Respirometry Test)

Version / remarks:

May 30, 2008

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Hess. Ministerium für Umwelt, Energie, Landwirtschaft und Verbraucherschutz

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, domestic, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): microorganisms from a domestic waste water treatment plant was supplied by the sewage plant Rossdorf, Germany
- Preparation of inoculum for exposure: The aerobic activated sludge used for this study was phase was decanted. The solid material was resuspended in tap water and centrifuged again. This procedure was done three times. An aliquot of the final sludge suspension was weighed, dried and the ratio of wet sludge to its dry weight was determined. Based on this ratio, calculated aliquots of washed sludge suspension, corresponding to 3.5 g dry material per litre were mixed with test water and aerated overnight. This suspension was used for the experiment.
- Concentration of sludge: 3.5 g dry material per litre
- Water filtered: no

Duration of test (contact time):

28 d

Initial conc.:

103.3 mg/L

Based on:

test mat.

Initial conc.:

300 mg/L

Based on:

ThOD

Remarks:

NH4

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium:
a) 8.5 g KH2PO4, 21.75 g K2HPO4, 33.4 g Na2HPO4 x 2 H2O, 0.5 g NH4Cl filled up with deionised water to 1000 mL volume; The pH-value was 7.4.
b) 11.25 g MgSO4 x 7 H2O filled up with deionised water to 500 mL volume
c) 18.2 g CaCl2 x 2 H2O filled up with deionised water to 500 mL volume
d) 0.125 g FeCl3 x 6 H2O filled up with deionised water to 500 mL volume
In order to avoid precipitation of iron hydroxide in the stock solution
d) one drop of concentrated HCl per litre was added before storage.
50 mL of stock solution a) and 5 mL of the stock solutions b) to d) were combined and filled up to a final volume of 5000 mL with deionised water.
- Test temperature: 22°C ± 1°C
- pH: 7.4 at the beginning and at the end
- pH adjusted: no
- Aeration of dilution water: continuous stirring in an air-conditioned room
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: Manometric Test System with test flasks containing a volume of approximately 500 mL (BSB/BOD-Sensor-System, Aqualytic Dortmund, Germany)
- Number of culture flasks/concentration: 2
- Method used to create aerobic conditions: test flasks were closed gas-tight by a measuring head, continous stirring
- Measuring equipment: pressure decrease (BSB/BODSensor- System, Aqualytic Dortmund, Germany)
- Details of trap for CO2 and volatile organics if used: Potassium hydroxide solution (45%)

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes
- Abiotic sterile control: yes
- Toxicity control: yes
- Other: Procedure control (sodium benzoate)

Reference substance:

benzoic acid, sodium salt

Preliminary study:

NA

Parameter:

% degradation (O2 consumption)

Value:

3

Sampling time:

28 d

Details on results:

The test item contains no nitrogen; therefore the evaluation of biodegradation has to be based on ThODNH4. The criterion for ready biodegradability under the conditions of a manometric respirometry test is the 10-day window, describing the period between reaching at least 10% degradation and 60% degradation. This period should not exceed 10 days.
The test item did not reach 10% biodegradation during incubation time; therefore no 10-day window could be established. The mean biodegradation at test end after 28 days was 3% (ThODNH4).
For details see attached result tables in "attached background material".

Results with reference substance:

The reference item sodium benzoate was sufficiently degraded to 79% after 14 days and to 91% after 28 days of incubation. The percentage biodegradation of the reference item confirms the suitability of the used aerobic activated sludge inoculum.

Biodegradation in the Toxicity Control

Percentage Biodegradation: In the toxicity control containing both, the test item and the reference item sodium benzoate, 27% (ThOD_NH4) biodegradation was noted within 14 days and 41% (ThOD_NH4) biodegradation after 28 days of incubation. According to the test guidelines, the test item can be assumed to be not inhibitory to the aerobic activated sludge microorganisms because degradation was >25% within 14 days.

According to the test guidelines the test item can be assumed to be not inhibitory to the aerobic activated sludge microorganisms because degradation was >25% within 14 days.

Abiotic Control

Oxygen Demand: The oxygen demand in the abiotic control was 0 mg/L during the test duration. There was no use to correct the degradation of the test item and toxicity control.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The degradation rate of the test item 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:

The registered substance was tested for ready biodegradation in an Manometric Respitometric Test according to OECD Guideline 301F following GLP.

Purpose

The purpose of this study was to identify the biodegradation potential of the registered substance in aquatic environments to provide a rational basis for environmental fate estimation for the test item.

Study design

The test item was exposed to aerobic activated sludge from the aeration tank of a domestic waste water treatment plant for 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control. This type of study is recognized by the international test guidelines and should provide a rational basis to assess the ready biodegradation properties of the test item when incubated with aerobic activated sludge. The endponits are the degradation rate of test item calculated by the oxygen consumption of the aerobic activated sludge microorganisms after 28 days of incubation.

Results

Biodegradation of the test material:

The test item contains no nitrogen; therefore the evaluation of biodegradation has to be based on ThOD_NH4. The criterion for ready biodegradability under the conditions of a manometric respirometry test is the 10-day window, describing the period between reaching at least 10% degradation and 60% degradation. This period should not exceed 10 days.

The test item did not reach 10% biodegradation during incubation time; therefore no 10-day window could be established. The mean biodegradation at test end after 28 days was 3% (ThOD_NH4). Therefore, the registered substance is considered to be not readily biodegradable based on ThOD_NH4.

Biodegradation of Sodium Benzoate:

The reference item sodium benzoate was sufficiently degraded to 79% after 14 days and to 91% after 28 days of incubation, thus confirming the suitability of the aerobic activated sludge inoculum used.

Biodegradation of the Toxicity Control:

In the toxicity control containing both, the test item and the reference item sodium benzoate, 27% (ThOD_NH4) biodegradation was noted within 14 days and 41% (ThOD_NH4) biodegradation after 28 days of

incubation. According to the test guidelines, the test item can be assumed to be not inhibitory to the aerobic activated sludge microorganisms because degradation was >25% within 14 days.

Conclusion

The registered substance is considered to be not readily biodegradable based on ThOD_NH4.

Description of key information

Key, 28 d, OECD 301F, GLP: not ready biodegradable

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

Biodegradation in water: screening test

The registered substance was tested for ready biodegradation in an Manometric Respitometric Test according to OECD Guideline 301F following GLP.

Purpose

The purpose of this study was to identify the biodegradation potential of the registered substance in aquatic environments to provide a rational basis for environmental fate estimation for the test item.

Study design

The test item was exposed to aerobic activated sludge from the aeration tank of a domestic waste water treatment plant for 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item, and functioned as a procedure control. This type of study is recognized by the international test guidelines and should provide a rational basis to assess the ready biodegradation properties of the test item when incubated with aerobic activated sludge. The endpoints are the degradation rate of test item calculated by the oxygen consumption of the aerobic activated sludge microorganisms after 28 days of incubation.

Results

Biodegradation of the test material:

The test item contains no nitrogen; therefore the evaluation of biodegradation has to be based on ThOD_NH4. The criterion for ready biodegradability under the conditions of a manometric respirometry test is the 10-day window, describing the period between reaching at least 10% degradation and 60% degradation. This period should not exceed 10 days.

The test item did not reach 10% biodegradation during incubation time; therefore no 10-day window could be established. The mean biodegradation at test end after 28 days was 3% (ThOD_NH4). Therefore, the registered substance is considered to be not readily biodegradable based on ThOD_NH4.

Biodegradation of Sodium Benzoate:

The reference item sodium benzoate was sufficiently degraded to 79% after 14 days and to 91% after 28 days of incubation, thus confirming the suitability of the aerobic activated sludge inoculum used.

Biodegradation of the Toxicity Control:

In the toxicity control containing both, the test item and the reference item sodium benzoate, 27% (ThOD_NH4) biodegradation was noted within 14 days and 41% (ThOD_NH4) biodegradation after 28 days of incubation. According to the test guidelines, the test item can be assumed to be not inhibitory to the aerobic activated sludge microorganisms because degradation was >25% within 14 days.

Conclusion

The registered substance is considered to be not readily biodegradable based on ThOD_NH4.