Alcohols, C8-14, γ-ω-perfluoro

Mode of degradation in actual use

Administrative data

Endpoint:

mode of degradation in actual use

Type of information:

other: Summary of the available biodegradation data

Adequacy of study:

weight of evidence

Reliability:

other: n.a.

Data source

Reference

Reference Type:

other company data

Title:

Unnamed

Materials and methods

Type of study / information:

An overview on the transformation pathway of fluortelomer residuals (8-2 FTOH) in the environment is given. Clariant has carried out the following fate studies:
- Stability in Sewage treatment plant (screening test) (Clariant GmbH, 2005) (Chapter 5.2.1)
- Stability in Anaerob Digested Sludge (Clariant GmbH, 2007) (Chapter 5.2.1)
- Stability in Aerobic soil (Clariant GmbH, 2011) (Chapter 5.2.3)
- Stability in a Simulated Landfill (Clariant GmbH, 2011) (Chapter 5.2.3)
Furthermore an article on the biotransformation of 8-2 FTOH in rats was published in 1981 by Hagen et al. . The fluorinated metabolites were identified with GC-Helium Microwave Plasma Detector. The results of the study can be compared with the results of the fate studies.

Test material

Test material information

Constituent 1

Reference substance name:

3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecan-1-ol

EC Number:

211-648-0

EC Name:

3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecan-1-ol

Cas Number:

678-39-7

Molecular formula:

C10H5F17O

IUPAC Name:

3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecan-1-ol

Details on test material:

- The biotransformation of 8-2 FTOH is compared in the different studies.
- 8-2 FTOH is used for the manufacturing of the polymer TRP-1989 (polyflouorinated acrylate).
- TRP-1989 is used as coating, e.g. on textiles
- 8-2 FTOH (the fluorotelomer building block in the polymer) is incorporated at > 99.9% as chemically-bound acrylate, only << 0.1% is either adsorbed or absorbed as low molecular weight residual.
- Due to technical reasons the investigations of the stability of this polymer on coated textiles was actually done with the purified solid polymer . The ratio of textile to polymer on a weight basis is very high which means the repellent polymer is in the ppm level on the textile.Testing coated textile would require very sensitive analytical methods which are not yet available. Therefore purified solid polymer was used intead of coated textiles.
- The polymer acts as a slow release dispenser of the residuals to the soil matrix and pore water

Results and discussion

Any other information on results incl. tables

The low molecular weight fluortelomer residuals can be biotransformed, e.g. by mammals or microorganisms, under aerobic and anerobic conditions.

Proposed transformation pathway for fluorotelomer residuals by Wang et al. 2005 (article which is referred to in both aerob and anerob studies, according to OECD TG 307 and 311, respectively):

8 -2 FTOH ---> 8 -2 FTA --->8 -2 FTUA --->7 -3 FTUA --->7 -3 ACID

"                            "

8 -1 Olefin ---> 7 -2 Olefin --->7 -2 sFTOH ---> PFOA

In the following the transformation products as derived from the stability tests with microorganisms are listed and compared to the metabolism of 8 -2 FTOH in mammals (male rats):

OECD 302B : Stability in Sewage treatment plant (screening test)

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After 14 days a degradation rate of 97 % was reached.

OECD 311: Stability in Anaerob Digested Sludge, 63 days

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8 -2 FTOH --->8 -2 FTA (main transformation product)

---> 8 -2 FTuA (low concentrations determined)

---> PFOA (low concentrations determined)

Half-life:

DT50 (8 -2 FTOH) > 63 days (42.7% of the initial 8 -2 FTOH concentration was anaerobically transformed after 63 days)

OECD 307 : Stability in Aerobic Soil, 2 years

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8 -2 FTOH ---> PFOA (main transformation product)

Note:

- The transformation pathway as suggested by Wang et al. 2005 was taken into account (see above) to choose the analytes (PFOA, 8 -2 FTuA, 8 -2 FTA) to be monitored.

- The intermediate transformation products 8 -2 FTA and 8 -2 FTuA were below the LOD of the analytical method

Half-life (according to Chen (Scenario 1), worst-case of three kinetic models used in the study):

DT50 (8 -2 FTOH) = 13.5 years considering the transformation of 8 -2 FTOH which is absorbed in the polymer (87.9% of the total initial residual alcohol)

DT50 (8 -2 FTOH) = 27.0 days considering only the 8 -2 FTOH residual which is <0.1% of the total available 8 -2 FTOH at test initiation and respresents 12.1% of the total intial residual alcohol)

Note:

- During the study (2 year study period) < 60 Mol-% of the amount of residual 8-2 FTOH at Day 0 were converted to PFOA.

LSR-Test (Lysimeter simulating a Landfill), 9 months

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8 -2 FTOH ---> PFOA (main transformation product)

Half-life:

DT50 (8 -2 FTOH) >> 38 years

Note:

- During the study (9 months study period) only 0.02 Mol-% (cotton) and 0.05 Mol-% (polyester) of the residual 8-2 FTOH were converted to PFOA.

- Total emission of residual 8 -2 FTOH into air bags at a temperature of 35°C: 0.93% (cotton) and 1.48% (polyester)

- Total remaining 8 -2 FTOH in the lysimeter at the end of the study: 99.1 Mol-% (cotton) and 98.5 Mol-% (polyester)

- The intermediate transformation products 8 -2 FTA and 8 -2 FTuA were below the LOQ of the analytical method

Transformation test with mammals (Hagen et al., 1981)

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8-2 FTOH ---------> PFOA (main metabolite)

                   ---------> 8-2 FTA (intermediate)

---------> unidentified metabolite (intermediate)

Note:

- 30 male rats were exposed to an oral dose of 400 mg 8 -2 FTOH /kg bw

- The metabolic products resulting from a single oral dose of the alcohol were isolated from the blood plasma and characterized by GC/MPD system. Appearance of PFOA as a metabolite and the observation of concomitant elevation in plasma and urinary inorganic fluoride suggests that the biotransformation of the alcohol to PFOA involves defluorination of the CF2 group adjacent to the CH2 group in the parent compound.

- Comparing rat plasma extracts at various times (2h, 6h and 48 h) post-dosage, it was seen that 8-2 FTA was present at high amounts after 2h and then decreased up to very low levels whereas the amount of PFOA increased with time (high levels after 48 h). 8-2 FTA can be therefore considered as an intermediate. Another unidentified metabolite was present at high levels in the 6 h-postdosage sample but after 48 h only low concentrations were determined.

Short-cuts and meaning:

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8 -2 FTOH (CAS-No. 678 -39 -7): C10H5F17O

PFOA (CAS-No. 335 -67 -1): 8 COOH or C8HF15O2

8 -2 FTA (CAS-No. 27854 -31 -5): 8 -2 COOH or 2 -PFOEA or C10H3F17O2

8 -2 FTuA (CAS-No. 70887 -84 -2): 8 -2 U COOH or 2H-HDF-2 -DA or C10H2F16O2

Applicant's summary and conclusion

Executive summary:

- The transformation of residual 8-2 FTOH under anaerobic conditions was observed to be very much slower than under aerobic ones.

- Based on the half-life estimations of the landfill simulation study (predominantly anaerob) and aerob degradation study according to OECD TG 307 it is concluded that the yearly contribution of the polymer to the global but also local PFOA is extremely low.