Ammonium undecafluorohexanoate

Endpoint summary

Additional information

Ammonium undecafluorohexanoate (CAS 21615-47-4) is characterized by a water solubility of 57610 mg/L (174 mmol/L determined by CMC (ST ring method vs. concentration), a vapour pressure of 4.47E-03 Pa at 25 °C (OECD 104) and a log Koc < 3. Due to the very low pKa value of 3.29 at 20 °C the anionic form of the acid is the predominant form in the environment. In aqueous medium NH₃generally exists as ammonium hydroxide. Evaporation to the atmospheric compartment is not expected due to its low volatility. The low log Koc of < 3 is indicative that the substance is not likely to adsorb to organic soil and sediment particles.
Hydrolysis is not considered to be a relevant degradation pathway since the substance does not contain any chemical groups allowing hydrolysis in contact with water. The substance is considered to be hydrolytically stable in the environment. Moreover, significant biodegradation is not expected based on the chemical structure of the substance. This is supported by information from (Q)SAR calculations and experimental data from structurally similar substances which were combined in a weight-of-evidence approach.
Bioaccumulation via aqueous exposure is considered to be low. Data are available investigating the bioaccumulation of perfluorohexanoic acid in fish (predominant chemical species due to dissociation of ammonium undecafluorohexanoate under environmental conditions). None of the available studies indicate accumulation in analysed fish tissue (carcass, liver, blood). Perfluorohexanoic acid could not be detected in fish tissues. Thus, the potential for accumulation of the substance is considered to be low.