Toxicological evaluation of sodium perfluorohexanoate

Sodium perfluorohexanoate [NaPFHx, F(CF2)5CO2Na, CAS#2923-26-4] was evaluated in acute, 90-day subchronic, one-generation reproduction, developmental and in vitro genetic toxicity studies. In the subchronic/one-generation reproduction study, four groups of young adult male and female Crl:CD(SD) rats were administered NaPFHx daily for approximately 90 days by gavage at dosages of 0, 20, 100, or 500mg/kg. Selected groups of rats were evaluated after 1- and 3-month recovery periods. Rats selected for reproductive evaluations were dosed for approximately 70 days prior to cohabitation, through gestation and lactation, for a total of about 4 months. The subchronic toxicity no observed adverse effect level (NOAEL) was 20mg/(kgday), based on nasal lesions observed at 100 and 500mg/(kgday). No effects were observed for neurobehavioral endpoints. NaPFHx was a moderate inducer of hepatic peroxisomal β-oxidation with a no observed effect level (NOEL) of 20 (male rats) and 100mg/(kgday) (female rats). Elevated hepatic β-oxidation levels were observed following 1-month recovery in male and female rats at 500mg/(kgday). No NaPFHx-related effects were observed on any reproductive parameters. The P1 adult rat NOAEL was 20mg/(kgday), based on reduced body weight parameters, whereas the NOAEL for reproductive toxicity was 100mg/(kgday), based on effects limited to reduced F1 pup weights. In the developmental study, female rats were dosed via gavage on gestation day (GD) 6–20 with the same doses of NaPFHx administered in the subchronic study. The maternal and developmental toxicity NOAEL was 100mg/(kgday), based on maternal and fetal body weight effects at 500mg/(kgday). NaPFHx is therefore concluded not to present a reproductive or developmental hazard. NaPFHx genotoxicity studies showed no mutations in the bacterial reverse mutation (Ames) assay or chromosome aberrations in human lymphocytes treated with NaPFHx in vitro. The lowest NOAEL from all of the studies was 20mg/(kgday) in the subchronic study based on nasal lesions. Benchmark doses (BMDL10) for nasal lesions were 13 and 21mg/(kgday) for male and female rats, respectively. The relevance of the nasal lesions to humans is not known.