Trifluoroacetic anhydride

Ecotoxicological Summary

Hazard for aquatic organisms

Freshwater

Hazard assessment conclusion:

PNEC aqua (freshwater)

PNEC value:

1 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

PNEC freshwater (intermittent releases):

0.1 mg/L

Marine water

Hazard assessment conclusion:

PNEC aqua (marine water)

PNEC value:

0.1 mg/L

Assessment factor:

100

Extrapolation method:

assessment factor

STP

Hazard assessment conclusion:

PNEC STP

PNEC value:

83.2 mg/L

Assessment factor:

10

Extrapolation method:

assessment factor

Sediment (freshwater)

Hazard assessment conclusion:

PNEC sediment (freshwater)

PNEC value:

4.6 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Sediment (marine water)

Hazard assessment conclusion:

PNEC sediment (marine water)

PNEC value:

0.46 mg/kg sediment dw

Extrapolation method:

equilibrium partitioning method

Hazard for terrestrial organisms

Soil

Hazard assessment conclusion:

PNEC soil

PNEC value:

8.3 µg/kg soil dw

Assessment factor:

100

Extrapolation method:

assessment factor

Hazard for predators

Secondary poisoning

Hazard assessment conclusion:

no potential for bioaccumulation

Additional information

Trifluoroacetic acid anhydride (TFAH) reacts violently with water and is instantaneously degraded in trifluoroacetic acid (TFA) which is the relevant substance for risk assessment and classification & labelling purposes.

In aqueous solution, the pH of the substance is naturally low (pH<4) and for testing on organisms either the sodium salt (NaTFA) or pH adjustment were required.

Aquatic toxicity

Among all the species tested, a toxic effect (growth inhibition) was found only for the algae Selenastrum capricornutum which lead to a R52/53 classification for the environment. The lowest value of the range of EC50 that lead to such a classification is 10 mg/L which is in line with the ErC50 for Selenastrum capricornutum calculated at 8.5 mg/L. In total six other freshwater algae and three marine algae were tested and no toxicity was found at the highest concentrations tested (up to 1997 mg/L TFA). No short term nor long term toxicty were found on the invertebrate Daphnia magna giving a EC50 (48h) > 999 mg/L and an NOEC (21d) = 25 mg/L of TFA . Also, no short term toxicity was found on the freshwater fish Danio rerio and an LC50(96h) > 999 mg/L TFA was derived. Therefore, it is postulated that, with high probability, the most sensitive species has been examined and that the lowest value in the range of toxicity consistent with a R52/53 classification can be use to derive the PNECs for the aquatic compartments.

The toxicty of TFA on microorganisms was investigated in a standard sludge respiration inhibition test. At the highest nominal test concentration less than 10% inhibition was noted and the NOEC/EC10 was established above 832 mg TFA/L.

Terrestrial toxicity

Two key studies are available for NaTFA, performed according to OECD 208 guideline on three different plants species. The lowest EC50 was measured for shoot growth of mung bean at 4.7 mg/kg DW and the NOEC was determined at 0.83 mg/kg DW for the three species. No relevant data are available on soil macroorganisms, terrestrial arthropods and soil microorganisms. It is assumed that there is no need to conduct this studies on TFAH based on low exposure and low toxicity considerations. Indeed, the substance have a low potential for bioaccumulation (Log Kow < 3, not highly adsorptive, Log Koc = 10 L/Kg (estimated by Kocwin v2.00 with MCI method) or 4.026 L/Kg (estimated by Kocwin v2.00 with Kow method)).

Environmental fate and pathways

TFA was found to be highly resistant to abiotic and biotic degradation and, coupled with its extreme chemical stability, these results suggest a very long lifetime for TFA in the environment.

Moreover, the substance is expected to have a low potential for bioaccumulation. The results of publications data 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 was very low.

Conclusion on classification

Classification according to Annex VI of Directive 67/548/EEC: TFAH is classify as R52/R53 for the environment (based on the toxicology observed on Selenastrum capricornutum).

GHS classification: Aquatic chronic 3/ H412