4-chloromethyl-4''-ethyl-2'-fluoro-[1,1':4',1''-terphenyl]

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:

2017-09-07 to 2017-10-05

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:

adopted 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)

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, non-adapted

Details on inoculum:

- Source of inoculum/activated sludge: sewage treatment plant Bensheim, Germany
- Pretreatment: The aerobic activated sludge used for this study was sedimented for 30 minutes, washed by centrifugation and the supernatant liquid phase was decanted. The solid material was re-suspended in test 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: pure water was used for preparation of reconstituted test water

Duration of test (contact time):

28 d

Initial conc.:

102.8 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Reconstituted Test Water was prepared as follows: Analytical grade salts were added to pure water to prepare the following stock solutions: a) 8.5 g KH2PO4, 21.75 g K2HPO4, 33.4 g Na2HPO4 x 2 H2O, 0.5 g NH4Cl filled up with pure water to 1000 mL volume; The pH-value was 7.4.; b) 11.25 g MgSO4 x 7 H2O filled up with pure water to 500 mL volume; c) 18.2 g CaCl2 x 2 H2O filled up with pure water to 500 mL volume; d) 0.125 g FeCl3 x 6 H2O filled up with pure 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 pure water.
- Solubilising agent: not used
- Test temperature: 22 +/-1 °C
- pH: 7.6 (start), 7.5 - 7.6 (end)
- pH adjusted: no
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: ManometricTest 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: not specified
- Method used to create anaerobic conditions: not applicable
- Measuring equipment: The change of pressure in the test flasks was measured by means of a manometric method (BSB/BOD-Sensor-System, Aqualytic Dortmund, Germany) each day.
- Test performed in closed vessels due to significant volatility of test substance: closed vessel was used due to measuring
- Test performed in open system: no
- Details of trap for CO2 and volatile organics: Potassium hydroxide olution(45 %) was used for trapping the produced carbon dioxide.

SAMPLING
No sampling was performed. The amount of O2 consumed by the activated sludge was calculated from the decrease of pressure in the reaction vessel measured every day.

CONTROL AND BLANK SYSTEM
- Inoculum blank: yes, 2 flasks, with 28.7 mg sludge/L
- Abiotic sterile control: yes, 1 flask, using test item (24.9 mg) and 5 mL CuSO4
- Toxicity control: yes, 1 flask, using test item (25.1 mg) and reference item (25.2 mg), with 28.7 mg sludge/L

STATISTICAL METHODS: not applicable

Reference substance:

benzoic acid, sodium salt

Key result

Parameter:

% degradation (O2 consumption)

Value:

1

Sampling time:

28 d

Details on results:

The mean biodegradation of the test item at test end after 28 days was 1 % (ThOD-NH4).

Results with reference substance:

The reference item sodium benzoate was sufficiently degraded to 80 % after 14 days and to 83 % after 28 days of incubation. The percentage biodegradation of the reference item confirms the suitability of the used aerobic activated sludge inoculum.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The test item is considered to be not readily biodegradable.

Executive summary:

The test item was investigated for its ready biodegradability in a manometric respirometry test according to OECD TG 301F over a period of 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. The test was conducted at 22 °C ± 1 °C in darkness. As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item and functioned as a procedure control. The reference item loading rate was 101.2 mg/L corresponding to an oxygen demand of about 168.6 mg/L (ThODNH4). The test item loading rate (initial concentration in medium C0) was 102.8 mg/L corresponding to an oxygen demand of about 253.2 mg/L (ThODNH4). The reference item sodium benzoate was sufficiently degraded to 80 % after 14 days and to 83 % after 28 days of incubation, thus confirming the suitability of the aerobic activated sludge inoculum used. In the toxicity control containing both, the test item and the reference item sodium benzoate, 32 % biodegradation was noted within 14 days and 33 % 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. The test item did not reach a mean biodegradation of 10 % during the incubation time of 28 days. The mean biodegradation at test end after 28 days was 1 % (ThODNH4). Therefore, the test item is considered to be not readily biodegradable based on ThODNH4.

Description of key information

The test item is considered to be not readily biodegradable (reference 5.2.1-1).

Key value for chemical safety assessment

Biodegradation in water:

not biodegradable

Type of water:

freshwater

Additional information

The test item was investigated for its ready biodegradability in a manometric respirometry test according to OECD TG 301F over a period of 28 days. The biodegradation was followed by the oxygen uptake of the microorganisms during exposure. The test was conducted at 22 °C ± 1 °C in darkness. As a reference item sodium benzoate was tested simultaneously under the same conditions as the test item and functioned as a procedure control. The reference item loading rate was 101.2 mg/L corresponding to an oxygen demand of about 168.6 mg/L (ThODNH4). The test item loading rate (initial concentration in medium C0) was 102.8 mg/L corresponding to an oxygen demand of about 253.2 mg/L (ThODNH4). The reference item sodium benzoate was sufficiently degraded to 80 % after 14 days and to 83 % after 28 days of incubation, thus confirming the suitability of the aerobic activated sludge inoculum used. In the toxicity control containing both, the test item and the reference item sodium benzoate, 32 % biodegradation was noted within 14 days and 33 % 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. The test item did not reach a mean biodegradation of 10 % during the incubation time of 28 days. The mean biodegradation at test end after 28 days was 1 % (ThODNH4). Therefore, the test item is considered to be not readily biodegradable based on ThODNH4.