Ammonium difluoro[1,1,2,2-tetrafluoro-2-(pentafluoroethoxy)ethoxy]acetate

Endpoint summary

Additional information

In a GLP-compliant OECD guideline 111 study, less than 10% degradation of the EEA ion of EEA-NH4 was observed after 5 days at 50 ºC at all pH concentrations (TNO Quality of Life, 2008a). The EEA ion of EEA-NH4 was considered hydrolytically stable at pH 4.0, pH 7.0 and pH 9.0.

No studies are available on photolysis in water or atmospheric degradation.

In a GLP-compliant, OECD 301C Modified MITI test biodegradation of EEA-NH4 was tested using activated sludge prepared from several sampling sites (return sludges from both city and industrial sewage treatment plants and surface water and surface soil). The test item was found to be not readily biodegradable after 28 days (Kurume Laboratory, 2005).

Simulation studies were not performed.

The degradation rate constants used in the assessment are:

Degradation for hydrolysis: 6.93E-07 d^-1

Degradation for photolysis: 6.93E-07 d^-1

Degradation rate in air: 0 d^-1

Degradation rate in the STP: 0 d^-1

Degradation rate in surface water: 1.39E-06 d^-1

Degradation rate in aerated sediment: 6.93E-07 d^-1

Degradation rate in soil: 6.93E-07 d^-1

The log Koc of the EEA ion of EEA-NH4 could not be determined using the HPLC-method. Therefore, the organic carbon-water partitioning coefficient (Koc) was calculated from the octanol-water partition coefficient (log Kow) using the equation from EUSES (predominantly hydrophobics). The calculated log Koc is 11.4 L/kg (log value = 1.06) from a log Kow of 1.18. This predicted value is used in the assessment. Further studies on transport and distribution of EEA-NH4 in the environment are not available.

The bioconcentration of EEA-NH4 in fish was studied according to OECD guideline 305 (Kurume Laboratory, 2006a). Bioaccumulation of EEA-NH4 in Japanese carp (Cyprinus carpio) was tested at 2 and 20 μg/L under flow-through conditions at 25^oC (nominal concentrations). The BCFs of EEA-NH4 were not more than 5.8 at 2 μg/L and 0.59 at 20 μg/L. Because the BCFs were below 100 it was assumed that steady state was reached within 28 days.The BCFs indicate a low potential for bioconcentration. The BCF of 5.8 is used in the assessment.