3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctan-1-ol

Biodegradation in water: screening tests

Administrative data

Endpoint:

biodegradation in water: inherent biodegradability

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Although data provided have a report year after 2008, the data was obtained from a journal article which does not provide GLP information.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

publication

Title:

6-2 Fluorotelomer alcohol aerobic biodegradation in soil and mixed bacterial culture

Author:

Liu J, Wang N, Szostek B, Buck R, Paniciroli P, Folsom P, Sulecki L and Bellin C

Year:

2009

Bibliographic source:

Chemosphere 78, 437–444

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 302 A (Inherent Biodegradability: Modified SCAS Test)

Deviations:

yes

Remarks:

Degradation was determined by qualitative analysis of the test substance with LC/MS/MS, study run for 90 days

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctan-1-ol

EC Number:

211-477-1

EC Name:

3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctan-1-ol

Cas Number:

647-42-7

Molecular formula:

C8H5F13O

IUPAC Name:

3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctan-1-ol

Details on test material:

- Purity: 99%

Study design

Oxygen conditions:

aerobic

Inoculum or test system:

activated sludge, industrial, adapted

Details on inoculum:

This study used a mixed aerobic bacterial culture developed from activated sludge previously exposed to fluorinated chemicals. However, the bacterial culture was not pre-exposed to any fluorinated chemicals immediately before conducting the biodegradation study.
After the sludge was collected from aeration tanks of an industrial wastewater treatment plant, it was allowed to settle for 5 min and 5 mL of the top phase was transferred to 50 mL of growth medium comprising of a mineral nutrient medium and 0.1% yeast extract. The culture was maintained at 20-25 °C by periodically transferring 0.5 mL of the culture into another 50 mL growth media twice a week. After four consecutive transfers, the culture was spun down to pellets and re-suspended in the mineral nutrient medium as an inoculum and was added to the sample solution to a final OD600 of 0.05 for the degradation study.

Duration of test (contact time):

0 - 90 d

Initial test substance concentration

Initial conc.:

2.8 other: µg/mL

Based on:

test mat.

Parameter followed for biodegradation estimation

Parameter followed for biodegradation estimation:

test mat. analysis

Details on study design:

TEST CONDITIONS
- Composition of medium: nutrient medium
- Test temperature: 20–25 °C
- Continuous darkness: yes
- Other: incubated on an orbital shaker at 150 rpm


TEST SYSTEM
- Culturing apparatus: 120-mL glass serum bottles sealed with natural rubber septa
- Number of culture flasks/concentration: Three treatments of duplicate vessels were prepared: (1) untreated (matrix) live culture with 6 µL ethanol; (2) test substance treated live culture; and (3) test substance treated sterile culture. At each sampling time point, a total of six test vessels were sacrificed for sample processing and extraction of tests substance and potential metabolites.
- Measuring equipment: 4900 Micro-GC; The O2 content was also measured at each time point in untreated live culture to approximate O2 content in treated live sample bottles.
- Test performed in closed vessels due to significant volatility of test substance: yes
- Other: The incubation was initiated by aseptically adding 30 mL of the mixed bacterial culture to each test vessel then dosing with 6 µL of test substance stock solution prepared in ethanol.


SAMPLING
- Sampling frequency: 0, 2, 7, 14, 28, 60, and 90 day
- Sampling method: Without breaking the seal, 1.0 mL of the headspace gas was sampled with a gas-tight syringe and analysed for the oxygen content with a 4900 Micro-GC. Then, without breaking the seal, 5 mL of culture was drawn out with a syringe for fluoride measurement. Finally, the entire sample vessel was extracted with 30 mL of acetonitrile injected with a syringe through the septum.
- Sample storage before analysis: frozen, ≈20 °C

Reference substance

Reference substance:

not required

Results and discussion

% Degradation

Parameter:

% degradation (test mat. analysis)

Remarks:

(Primary biodegradation)

Value:

>= 97.2 - <= 98.4

Sampling time:

7 d

Remarks on result:

other: Incomplete mineralisation; Transformation products were identified

Details on results:

Test substance biodegradation in mixed bacterial culture was rapid with an estimated half-life of 1.3 days assuming first-order kinetics. The test substance concentration decreased rapidly and stabilised after day 7 at 1.6 - 2.8% of the total mass applied at day 0 (2.8 µg/mL). This would be equal to 97.2 - 98.4% primary degradation by day 7.

Any other information on results incl. tables

Metabolite concentrations reached steady-state after 14 – 28 days.

Applicant's summary and conclusion

Validity criteria fulfilled:

yes

Interpretation of results:

other: Primary biodegradation observed. This study would infer that the test substance would not be regarded as readily or inherently biodegradable.

Conclusions:

This study and the conclusions which are drawn from it fulfill the quality criteria (validity, reliability, repeatability).
97.2 - 98.4% primary degradation by day 7

Executive summary:

Test substance biodegradation was evaluated at 2.8 μg/mL and 20 μg/mL (for metabolite identification) for 90 days in a mixed aerobic bacterial culture developed from activated sludge previously exposed to fluorinated chemicals. Test vessels were 120-mL glass serum bottles sealed with natural rubber septa and the vessels were incubated on an orbital shaker at 150 rpm at 20 – 25 °C. The replicate test and control vessels were extracted and analysed at 0, 2, 7, 14, 28, 60, and 90 days for the test substance and metabolites.

Primary biodegradation in the mixed bacterial culture was rapid with an estimated half-life of 1.3 days assuming first-order kinetics. Test substance concentration decreased rapidly and stabilised after day 7 at 1.6 - 2.8% of the total tests substance mass applied at Day 0. This would be equal to 97.2 - 98.4% primary degradation by day 7. Metabolite concentrations reached steady-state after 14 – 28 days.