2-Pentene, 1,1,1,2,3,4,5,5,5-nonafluoro-4-(trifluoromethyl)-, (E)-

Endpoint summary

Additional information

HFP kinetic dimer is volatile (VP, 34700 Pa at 20 °C) and has a water solubility of 649 µg/L at 22.3 °C. Its experimentally determined Henry's Law constant is 1.40E+07 Pa m³/mol (138 atm m³/mole) at 22 °C. HFP kinetic dimer is difficult to retain in aqueous solution, and the key fish, daphnia and algae toxicity studies used entirely closed systems without headspace throughout the test to obtain consistent concentrations, with analytical confirmation of test substance concentration. Test vessels at the highest test substance concentration intentionally contained a small amount of undissolved test material, although lower concentrations did not. Measurable concentrations of HFP kinetic dimer were present throughout the exposure period at higher concentrations, although concentrations fell below the limit of quantitation at lower concentrations. Loss of quantitation did not affect the results of any key study. The most sensitive species was Daphnia magna, for which 50% effect was exceeded in the dilution series. In the algae test, the 50% effect threshold was crossed between the two highest concentrations, with the aforementioned undissolved material present at the highest level. Saturated solutions did not attain 50% effect in the fish.

Two additional studies of fish toxicity were deemed not reliable. All of the key studies were performed in accordance with internationally-accepted test guidelines and Good Laboratory Practice (GLP) standards. Therefore, the studies are reliable, and the results suitable for purposes of Risk Assessment, Classification & Labeling, and PBT Analysis.

The primary fate of HFP kinetic dimer is expected to be photolysis to HF, TFA and iPFBA. These acids are highly soluble and are expected to reside ultimately in the aquatic compartment. HF and TFA are subjects of existing risk assessments.

Table 1, HFP kinetic dimer aquatic toxicity results
Species	Endpoint	Concentration	Results parameter	Reliability (Klimisch)
Fish
Danio rerio	96-hour LC50	> 12 µg/L ¹ >5 mg/L ²	mortality	1
Danio rerio	96-hour LC50	350 - 500 mg/L	mortality	4
Pimephales promelas ³	96-hour LC50 96-hour LC50	<1.0 mg/L ² >1.0 mg/L ²	mortality	3
Invertebrate
Daphnia magna	48 -hour EC50	14 µg/L ¹	immobilization	1
Algae
Pseudokirchneriella subcapitata	72-hour EC50 72-hour EC10 72-hour NOEC	35 µg/L ¹ 17 µg/L ¹ 3.3 µg/L ¹	growth rate	2
1, Measured concentration 2, Nominal concentration 3, The first result is of direct addition of HFP dimer, the second result is of a water accomodated fraction