3-ethoxy-1,1,1,2,3,4,4,5,5,6,6,6-dodecafluoro-2-(trifluoromethyl)-hexane

Short-term toxicity to aquatic invertebrates

Description of key information

Key result for CAS# 297730-93-9:
Proposed adaptation of testing requirements due to lack of exposure.
Key result for PFBA (degradation product):
96-h LC50 (OECD203) to Hyalella azteca: 971 mg/L.

Additional information

We propose to waive testing of short-term toxicity to aquatic invertebrates on CAS# 297730-93-9 due to lack of exposure. The primary fate of CAS# 297730-93-9 is expected to be photolysis to HF, TFA, and PFBA. These acids are highly soluble and are expected to reside ultimately in the aquatic compartment. HF and TFA are subjects of existing risk assessments. Seven studies of PFBA toxicity to aquatic invertebrates were conducted using four species: Hyalella azteca, Daphnia magna, Ceriodaphnia dubia and Lumbriculus variegatus. Two studies, for Hyalella azteca and Daphnia magna,were performed in accordance with accepted test guidelines and GLP criteria, had supporting analytical data, and were reliable without restriction. The result for the most sensitive species (Hyalella azteca) was chosen as the key study for PFBA.  A similar study for Daphnia magna had a 48-hour EC50 (mobility) of 3475 mg/L. Additional rangefinding studies support this assessment of toxicity to aquatic invertebrates: 48-hour EC50 (mobility) of 3162 mg/L for both Daphnia magna and Ceriodaphnia dubia, and a 96-hour LC50 of 3162 mg/L for Lumbriculus variegatus. These were generally in accord with test guidelines and have analytical support for the nominal concentrations used, but were not GLP and, as rangefinding studies, had a factor of ten difference in concentrations. These are nevertheless considered reliable with restrictions. One remaining study was not considered reliable because of an inappropriate test method. PFBA is not acutely toxic to aquatic invertebrates according to GHS criteria.