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Environmental fate & pathways

Additional information on environmental fate and behaviour

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Administrative data

Endpoint:
additional information on environmental fate and behaviour
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
not specified
Reliability:
4 (not assignable)
Rationale for reliability incl. deficiencies:
other: Studies were not according to international guideline and without GLP. The report is not enough well documented to assess the reliability of the data.
Cross-referenceopen allclose all
Reason / purpose for cross-reference:
reference to same study
Reason / purpose for cross-reference:
reference to other study

Data source

Reference
Reference Type:
review article or handbook
Title:
Unnamed
Year:
1993
Report date:
1993

Materials and methods

Principles of method if other than guideline:
Chemical stability results are reported. An attempt was performed to isolate bacteria that can degrade MFA, DFA and TFA in a minimal media with the fluoroacetate as the only carbon source or in an enriched media having additional carbon sources. Purification of the fluoroacetate dehalogenase enzyme was also performed.
GLP compliance:
no
Type of study / information:
Chemical stability of Fluoroacetates, biological dehalogenation and enzymic dehalogenation

Test material

Constituent 1
Chemical structure
Reference substance name:
Trifluoroacetic acid
EC Number:
200-929-3
EC Name:
Trifluoroacetic acid
Cas Number:
76-05-1
Molecular formula:
C2HF3O2
IUPAC Name:
trifluoroacetic acid
Test material form:
liquid
Details on test material:
Name of test material (as cited in study report): trifluoroacetic acid

Results and discussion

Any other information on results incl. tables

Chemical stability of Fluoroacetates:

The half-live of TFA was 150 years under the conditions of the test (10% or 3.33 N NaOH at 81°C). TFA is about 100 000 times more stable than MFA in base. This suggests that base hydrolysis of TFA is not significant degradation route near or below neutral pH. These results support the idea that TFA will have an extremely long lifetime in normal environments.

Biological dehalogenation:

The inflow and outflow TFA concentrations were determined to be 0.12 mM and 0.15 mM, respectively, while the inflow and outflow fluoride concentrations were 3.0 mM and 2.3 mM, respectively. These results indicate that no TFA is being degraded by a population of microbes exposed to 10 ppm levels of TFA for over a decade.

Enzymic dehalogenation:

TFA is dehalogenated by our dehalogenase at a rate of about 0.02 day-1. This extremely slow rate is compatible with the additional chemical stability of TFA demonstrated above. The kinetic data suggests that the degradation of TFA by dehalogenases will be insignificant, since the catalytic rate enhancement for defluoronation of MFA is approaching an upper limit for known enzymes and TFA is several orders of magnitude more stable than MFA.

Applicant's summary and conclusion

Conclusions:
In conclusion, the half-live of TFA was 150 years under the conditions of the test (10% or 3.33 N NaOH at 81°C). This suggests that base hydrolysis of TFA is not significant degradation route near or below neutral pH. Coupled with no significant biological degradation of TFA, these results suggest a very long lifetime for TFA in the environment.
Executive summary:

Studies were performed for relate the biological fate of Trifluoroacetic acid (TFA). Chemical stability of Fluoroacetates, biological dehalogenation, and enzymic dehalogenation were measured.

Chemical stability of Fluoroacetates:

The half-live of TFA was 150 years under the conditions of the test (10% or 3.33 N NaOH at 81°C). TFA is about 100 000 times more stable than MFA in base. This suggests that base hydrolysis of TFA is not significant degradation route near or below neutral pH. These results support the idea that TFA will have an extremely long lifetime in normal environments.

Biological dehalogenation:

The inflow and outflow TFA concentrations were determined to be 0.12 mM and 0.15 mM, respectively, while the inflow and outflow fluoride concentrations were 3.0 mM and 2.3 mM, respectively. These results indicate that no TFA is being degraded by a population of microbes exposed to 10 ppm levels of TFA for over a decade.

Enzymic dehalogenation:

TFA is dehalogenated by our dehalogenase at a rate of about 0.02 day-1. This extremely slow rate is compatible with the additional chemical stability of TFA demonstrated above. The kinetic data suggests that the degradation of TFA by dehalogenases will be insignificant, since the catalytic rate enhancement for defluoronation of MFA is approaching an upper limit for known enzymes and TFA is several orders of magnitude more stable than MFA.

In conclusion, any evidence for significant biological degradation of TFA has been found. Coupled with its extreme chemical stability, these results suggest a very long lifetime for TFA in the environment.