Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

No bioaccumulation studies obtained from established experimental protocols are available for TFA. The substance is expected to have a low potential for bioaccumulation according to its log Kow of 0.79 at 25°C. However, because of the structural similarity of TFA to acetate, a biochemical intermediate and microbial nutrient, it was suspected that organisms might use the fluorinated compound to synthesize biomolecules such as lipids and acetylated proteins and several non standard experimental studies were conducted on aquatic and terrestrial organisms.

The results indicate a low level of incorporation of TFA by natural microbial communities and thus their potential to serve as a point for TFA to enter into the food web. Overall incorporation of radioactive TFA in aquatic organisms spanning a range of trophic levels (microbial communities, oligochaetes, macroinvertebrates, Callitriche sp., Lemna sp., and Impatiens capensis) was very low (low ppb range for microbial communities and low ppm range for oligochaetes and jewelweed) and TFA was incorporated into their biomolecule fractions so that it was no longer extracted as TFA and thus was metabolically transformed. Finally, radioactive TFA accumulated around ten times by the algal cells from the media is reported in the Toxicity to aquatic algae and cyanobacteria section.

Bioaccumulation data in terrestrial organisms are reported in the toxicity to terrestrial plants section. Pines accumulated TFA as a function of concentration applied and the results indicated that atmospheric uptake may not be the dominant pathway of uptake in environmental conditions but rather root uptake. TFA accumulation by the plant Lycopersicon esculentum showed no extensive metabolism and that TFA is transported through the stem and accumulates in the leaves up to final concentrations of 10 to 20 µmol/g ww. A bioconcentration factor (BCF) of 43 after 35 days of exposure of the root in an aqueous medium was measured for the wheat. Sunflower seedlings were exposed to TFA in aquous medium and bioconcentration factor (BCF) of approximately 22 and 5 after 12 days were found in leaf tissue and stem tissue, respectively. Root tissue reached apparent equilibrium after 5 days exposure with a BCF of approximately 3. All tissues showed a decline in TFA residue concentrations on transfer to clean medium with some evidence of depuration.

In conclusion, these results show that TFA does not accumulate significantly in lower aquatic life forms such as bacteria, algae, small invertebrates, oligochaete worms and in some aquatic and terrestrial plants.

Based on the above data, a waiving for testing bioaccumulation is proposed.