Toxicity of 1,1,1-trichloro-2-propanone in Sprague-Dawley rats

1,1,1-Trichloro-2-propanone (1,1,1-TCP) has been identified as a chlorination by-product in finished drinking water supplies. Since little was known of its oral toxicity, exposure studies were conducted with male and female Sprague-Dawley rats (10 males and 10 females/group) exposed by corn oil gavage at 0, 16, 48, 161, or 483 mg/kg for 10 d or 0, 30, 90, or 270 mg/kg for 90 d. Evaluations included mortality, clinical signs, body weight, food consumption, ophthalmology, hematology, clinical chemistry, urinalysis, organ weights, gross pathology, and histopathology. In the 10-d study, severe toxicity was observed at the highest dose level, since most treated animals (8/10 males and 7/10 females) died. Toxicity was also noted at 161 and 48 mg/kg. At 161 mg/kg, 2 males died and an increase in liver weights in both sexes was observed. Acanthosis and hyperkeratosis of the forestomach was present in males and females at 48 mg/kg and above. In the 90-d study, toxicity was significant at 270 mg/kg, with acanthosis and hyperkeratosis of the forestomach evident in most animals and ataxia in about one-half of them. Retinal degeneration, increased serum potassium, and increased blood urea nitrogen were present in females and increased blood calcium in males at that same dose level. Acanthosis and hyperkeratosis were observed in both sexes, and retinal degeneration was prominent in 2 females at 90 mg/kg. It was concluded that 16 mg/kg was the NOAEL (no observed adverse effect level) for the 10-d study while 30 mg/kg was the NOAEL for the 90-d exposure of Sprague-Dawley rats to 1,1,1,-trichloro-2-propanone.