Sodium 6,14-diethyl-1,1,1,2,2,18,18,19,19,19-decafluoro-8,12-dioxo-10-({[1-(2,2,3,3,3-pentafluoropropoxy)butan-2-yl]oxy}carbonyl)-4,7,13,16-tetraoxanonadecane-9-sulfonate

Biodegradation in water: screening tests

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 OCT 2015 - 14 MAR 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 301 C (Ready Biodegradability: Modified MITI Test (I))

Version / remarks:

1981

Deviations:

no

GLP compliance:

yes

Oxygen conditions:

aerobic

Inoculum or test system:

mixture of sewage, soil and natural water

Details on inoculum:

- Source of inoculum/activated sludge (e.g. location, sampling depth, contamination history, procedure): The sludge, water and soil were sampling from 10 sites on 16th Sep. 2015.
- City sewage plant: LongHua Wastewater Treatment Plant, JinShan Wastewater Marine Disposal Treatment Plant, LangXia Wastewater Treatment Plant
- lndustry sewage plant: Sino French Water
- River: Suzhou River, Chuanyang River, Huangpu River
- Lake: Dianshan Lake
- Sea: Hangzhou Bay, estuary (Changjiang estuary)
All samples were mixed by stirring in a single container for 1 h and then settled for 1 h. The supernatant was transferred to a culture tank after removing the floating foreign matter. The culture was aerated the temperature was maintained at 25 ± 2°C and adjusted to pH 7.0 ± 1.0. Approximately 1/3 of the whole volume of the supernatant was removed and an equal volume of synthetic sewage (1g of glucose, 1g of peptones and 1g of monopotassium phosphate are dissolved in 1 litre of water and the solution is adjusted to pH 7.0 ± 1.0 with sodium hydroxide) was added to the remaining portion of the supernatant everyday.
The inoculum consists of samples from multipe sites to cover different environmental conditions. The above inoculum is suitable to investigate different potential exposure scenarios of the test substance in the test.
BOD determination started at 11th Nov. 2015. A fresh sample of activated sludge was collected from the culture tank cleaned and washed three times with mineral medium. The sludge was separated by centrifuging for 20 minutes at about 4000 rpm. A small amount of the washed sludge was weighed and dried to calculate the water content (105°C, 1h). The dry weight was 6.96 %.
Wet sludge was suspended in the mineral culture medium to obtain a concentration of 2 g dry matter/L. The sludge suspension was used as the inoculum after 30 min stirring at 500 rpm. The final concentrations of dry matter in inoculums blank and test substance are 100 mg/L, in the other test groups (except abiotic control) the concentration is 30 mg/L.

Duration of test (contact time):

28 d

Initial conc.:

30 mg/L

Based on:

test mat.

Parameter followed for biodegradation estimation:

DOC removal

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral culture medium was prepared by the following stock solutions which were prepared by using AR reagents: 3 mL each of solution (a), solution (b), solution (c) and solution (d), and ultra pure water were made up to 1000 mL. The pH was adjusted to about 7.0.
solution (a): KH2PO4 8.50 g/L, K2HPO4 21.75 g/L, Na2HPO4·2H2O 44.60 g/L, NH4CI 1.70 g/L
Solution(b) MgSO4·7H2O 22.50 g/L
Solution(c) CaCl2 27.50 g/L
Solution( d) FeCl3·6H2O 0.25 g/L
12.5 mL sludge suspension filled up with mineral medium to 250 mL total volume
- Test temperature: 24.6 - 25.3°C
- pH: initial pH values 7.01 - 7.35
- pH adjusted: yes

TEST SYSTEM
- Culturing apparatus: Brown bottles with the volume of 500 mL were used.
- Number of culture flasks/concentration: 3
- Measuring equipment: An automated closed-system oxygen consumption measuring apparatus (BOD-meter) is used
- Test performed in closed vessels due to significant volatility of test substance: An automated closed-system
- Details of trap for CO2 and volatile organics if used: The CO2 is absorbed by sodium hydroxide

SAMPLING
- Sampling frequency: daily
- Sampling method: An automated closed-system oxygen consumption measuring apparatus (BOD-meter) is used
- Sample storage before analysis: The samples were stored in refrigerator (2 - 8°C) after pretreatment if the samples were not analyzed directly in 24h.

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2 bottles inoculum blank control
- Abiotic sterile control: 1 bottle abiotic control
- Toxicity control: 1 bottle toxicity control
- Other: 2 bottles inoculum blank control for procedure control

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (DOC removal)

Value:

9

Sampling time:

28 d

Details on results:

Procedure control group average biodegradation rate in 7 d and 14 d were 69% and 77%, respectively. This shows that the activity of the inoculum meets the test requirements. The degradation percentage of toxicity control on day 14 was 52 %, which was higher than the toxicity inhibition level (> 25 %). lt is concluded that the test substance has no inhibitory effects on the inoculum at the concentration of 30 mg/L.
The results of DOC determination showed that the DOC of inoculum control group (IB), test substance group (TS) and abiotic control group (AC) at zero-time were 1.51 mg/L, 14.80 mg/L and 15.04 mg/L, respectively. The DOC of IB was 1.20 mg/L, the average DOC of TS was 14.96 mg/L and the DOC of AC was 15.04 mg/L at the 28th day. The DOC removal of test substance at the 28th day was 9%.

Results with reference substance:

According to the cumulative oxygen consumption, the mean degradation percentage of the reference substance were 69% and 77% after 7 and 14 days, respectively. Quality control requirements of the test are that the degradation percentage of the reference substance exceeds 40 % and 65 % after 7 days and 14 days, respectively. Hence, the test is considered to be valid.

Validity criteria fulfilled:

yes

Interpretation of results:

not inherently biodegradable

Conclusions:

The test substance was not inherent biodegradable under the present test conditions.

Executive summary:

The study of inherent biodegradation was performed in compliance with GLP and according to OECD Guideline 302C, the modified MITI test II "Ministry of environmental pratection of the people's Republic of China, The Guidelines for the Testing of Chemicals-Degradation and Accumulation, 2013, 302C lnherent Biodegradability: Modified MITI Test II" and "OECD, Guidelines for the Testing af Chemicals, 1981, 302C lnherent Biodegradability: Modified MITI Test (II)".

The results of biochemical oxygen demand (BOD) indicated that the cumulative oxygen consumption level of three replicates of test substance group were 103 mg/L , 104 mg/L and 101 mg/L, respectivly. They were very similar to the mean oxygen consumption of blank controls (110 mg/L). The calculated percentage biodegradation based on the BOD determination showed that this test substance is not biodegradable. The mean percentage biodegradation of the test substance in the 28th day was -4% based on the calculated results of LC-MS analysis. The mean percentage biodegradation of test substance in the 28th day was 9% based on the calculated results of DOC analysis.

The test substance was not inherent biodegradable under the present test conditions.

Reference 2

Endpoint:

biodegradation in water: ready biodegradability

Type of information:

experimental study

Adequacy of study:

key study

Study period:

05 APR 2011 - 03 MAY 2011

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:

OECD-Guideline No. 301 F for Testing of Chemicals (adopted July 17, 1992)

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 (e.g. location, sampling depth, contamination history, procedure): Municipal sewage treatment plant, D-31137 Hildesheim. Activated sludge from the sewage plant at Hildesheim is well suited as it receives predominantly municipal sewage and hardly any industrial chemical waste.
- Pretreatment: The activated sludge was washed twice with autoclaved tap water. After the second washing the settled sludge was filled up with mineral salts medium and was maintained in an aerobic condition by aeration for 4 hours. Thereafter the sludge was homogenized with a blender. The supernatant was decanted and maintained in an aerobic condition by aeration with CO2-free air for 4 days.
- Concentration of sludge: 10 mL/L were used to initiate inoculation.
- Initial cell/biomass concentration: 10E7 - 10E8 CFU/L
- Water filtered: no

Duration of test (contact time):

28 d

Initial conc.:

70 mg/L

Based on:

test mat.

Remarks:

corresponding to an oxygen demand (ThOD) of 77.0 mg O2/L in the test vessel

Parameter followed for biodegradation estimation:

O2 consumption

Details on study design:

TEST CONDITIONS
- Composition of medium: Mineral salts medium according to OECD 301 F
- Test temperature: 20.5 - 21.5 °C (The temperature in the incubator was documented continuously throughout the test by a hygrothermograph.)
- pH: 7.63 - 7.68 at test start, 7.52 - 7.79 at test end (At test start the pH-values of the test solutions in the measuring flasks (before dividing) and at test end the pH-values of the test solutions in the brown glass bottles were determined.)
- pH adjusted: no
- Continuous darkness: yes

TEST SYSTEM
- Culturing apparatus: All test solutions were prepared in measuring flasks in demineralised water with the required amounts of mineral medium stock solutions and 10 mL/L inoculum. The test item was weighed out and demineralised water was added. After ultrasonic treatment it was transferred into the measuring flasks. The reference item was weighed out and transferred into the measuring flasks with demineralised water. 250 ml measuring flasks were used to place 250 mL of the test solutions in the test vessels (brown glass bottles with 500 mL volume).
- Number of culture flasks/concentration: 2 x test item, 1 x procedure control, 1 x toxicity control, 2 x inoculum control
- Method used to create aerobic conditions: continous stirring
- Measuring equipment: The bottles were closed with Oxi-Top® measuring heads and the measuring system was activated.
- Details of trap for CO2 and volatile organics if used: A rubber sleeve with soda lime was hung into the opening of the bottles to absorb evolved CO2.

SAMPLING
- Sampling frequency: The oxygen consumption was determined continuously from the pressure in the incubation vessels by OxiTop® measuring system at 360 measuring points (every 112 minutes) during the 28 d incubation period.

CONTROL AND BLANK SYSTEM
- Inoculum blank: 2
- Toxicity control: 1

STATISTICAL METHODS: Excel, MICROSOFT CORPORATION SigmaPlot (Windows), SPSS CORPORATION

Reference substance:

benzoic acid, sodium salt

Parameter:

% degradation (O2 consumption)

Value:

7

Sampling time:

28 d

Details on results:

Theoretical Oxygen Demand
The biodegradation in % was calculated based on the ThOD of 1.10 mg O2/mg test item.

Colony Forming Units of the Inoculum
Colony forming units (CFU) of the inoculum were determined at test start by standard dilution plate count: 2.3 x 10xE9 CFU/L

Results of the Functional Control
The pass level of a biodegradation > 60 % was reached after 2 days. The validity criterion that the degradation should be > 60 % after 14 d was fulfilled

Results of the Toxicity Control
In the toxicity control the biodegradation achieved 49 % after 14 days. After 28 days the biodegradation came to 50 %. The validity criterion that the test item should not inhibit the biodegradation of the reference item was fulfilled.

Course and Stages of Biodegradation of Functional Control and Test Item
In case of the functional control, the adaptation phase changed to degradation phase after 1 day (degradation > 10 %). The pass level > 60 % was reached after 2 days. The biodegradation rate came to a maximum of 93 % on day 24.
The test item replicate 1 reached the 10 % level (beginning of biodegradation) after 19 days, test item replicate 2 after 9 days. The 60 % pass level was not reached within 28 days. After 28 days the mean biodegradation was 7 %.
The test item is classified as not readily biodegradable in the 10-d-window and after 28 days.

Validity criteria fulfilled:

yes

Interpretation of results:

not readily biodegradable

Conclusions:

The degradation rate of the test material 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 ready biodegradability of the test material was determined with a non adapted activated sludge in the Manometric Respirometry Test according to OECD Guideline 301 F for a period of 28 days. The test item concentration selected as appropriate was 70 mg/L, corresponding to a ThOD of 77.0 mg O₂/L per test vessel. The oxygen was depleted by the respiration of bacteria and the degradation was followed by measuring the oxygen concentration. The biodegradation rate is therefore expressed as the percentage BOD (biological oxygen demand) and was calculated for each study day.

The mean oxygen depletion in the inoculum control was 4.2 mg O₂/L on day 28.

In order to check the activity of the test system sodium benzoate was used as functional control. The pass level > 60 % was reached after 2 days. The biodegradation rate came to a maximum of 93 % on day 24.

In the toxicity control containing both test and reference item 49 % degradation occurred within 14 days. After 28 days the biodegradation came to 50 %. The degradation of the reference item was not inhibited by the test item.

The test item replicate 1 reached the 10 % level (beginning of biodegradation) after 19 days, test item replicate 2 after 9 days. The 60 % pass level was not reached within 28 days. After 28 days the mean biodegradation was 7 %.

The validity criteria of the guideline are fulfilled.

Based on the obtained results, he test material is classified as not readily biodegradable in the 10-d-window and after 28 days.

Description of key information

Inherent biodegradation, OECD 302C, GLP, not biodegradable

Ready biodegradation, OECD 301F, GLP, not readily biodegradable

Key value for chemical safety assessment

Biodegradation in water:

under test conditions no biodegradation observed

Type of water:

freshwater

Additional information

Ready Biodegradability, Fiebig, 2011

The ready biodegradability of the test material was determined with a non adapted activated sludge in the Manometric Respirometry Test according to OECD Guideline 301 F for a period of 28 days. The test item concentration selected as appropriate was 70 mg/L, corresponding to a ThOD of 77.0 mg O₂/L per test vessel. The oxygen was depleted by the respiration of bacteria and the degradation was followed by measuring the oxygen concentration. The biodegradation rate is therefore expressed as the percentage BOD (biological oxygen demand) and was calculated for each study day.

The mean oxygen depletion in the inoculum control was 4.2 mg O₂/L on day 28.

In order to check the activity of the test system sodium benzoate was used as functional control. The pass level > 60 % was reached after 2 days. The biodegradation rate came to a maximum of 93 % on day 24.

In the toxicity control containing both test and reference item 49 % degradation occurred within 14 days. After 28 days the biodegradation came to 50 %. The degradation of the reference item was not inhibited by the test item.

The test item replicate 1 reached the 10 % level (beginning of biodegradation) after 19 days, test item replicate 2 after 9 days. The 60 % pass level was not reached within 28 days. After 28 days the mean biodegradation was 7 %.

The validity criteria of the guideline are fulfilled.

Based on the obtained results, the test material is classified as not readily biodegradable in the 10-d-window and after 28 days.

Inherent Biodegradability, OECD 302C, Deng, 2016

The study of inherent biodegradation was performed in compliance with GLP and according to OECD Guideline 302C, the modified MITI test II "Ministry of environmental pratection of the people's Republic of China, The Guidelines for the Testing of Chemicals-Degradation and Accumulation, 2013, 302C lnherent Biodegradability: Modified MITI Test II" and "OECD, Guidelines for the Testing af Chemicals, 1981, 302C lnherent Biodegradability: Modified MITI Test (II)".

The results of biochemical oxygen demand (BOD) indicated that the cumulative oxygen consumption level of three replicates of test substance group were 103 mg/L , 104 mg/L and 101 mg/L, respectively. They were very similar to the mean oxygen consumption of blank controls (110 mg/L). The calculated percentage biodegradation based on the BOD determination showed that this test substance is not biodegradable. The mean percentage biodegradation of the test substance in the 28th day was -4% based on the calculated results of LC-MS analysis. The mean percentage biodegradation of test substance in the 28th day was 9% based on the calculated results of DOC analysis.

The test substance was not inherent biodegradable under the present test conditions.