The acute toxicity evaluation of a low-temperature hydraulic fluid.

A low-temperature version of MIL-H-83282 (LT 83282) is a candidate hydraulic fluid to be used as a replacement for the current low-temperature fluid used on Strategic Air Command aircraft. A single neat dose of 0.1 mL LT 83282 into New Zealand White (NZW) rabbit eyes resulted in slight conjunctival irritation for up to 24 hr after treatment in two of nine rabbits. Rinsing the eyes after treatment appeared beneficial. A single treatment of 0.5 mL neat LT 83282 to rabbit skin produced no irritation. A total of 40% of the guinea pigs receiving repeated dermal application of the fluid demonstrated a positive sensitization response. A single oral dose of 5 g LT 83282/kg body weight given to five male and five female Fischer 344 (F-344) rats and a single dermal application of 2 g LT 83282/kg body weight applied to five male and five female NZW rabbits resulted in no deaths. Inhalation exposures to aerosol concentrations of LT 83282 resulted in an LC50 of 2.13 and 1.50 mg/L for male and female F-344 rats, respectively. No clinical signs of acute delayed neurotoxicity were observed in hens twice dosed at limit levels (5 g/kg) and observed for 21 days.

Evaluation of the acute toxicity of silahydrocarbon.

Silahydrocarbon (SHC) is a base stock for a candidate high-temperature hydraulic fluid. Because United States Air Force personnel working with SHC may be exposed to potential health hazards, a complete battery of acute toxicity tests was performed with the fluid. A single neat dose of 0.1 mL SHC into New Zealand White (NZW) rabbit eyes resulted in slight conjunctival irritation 1 hr after treatment in all unflushed eyes and one of three flushed eyes. Conjunctival irritation persisted through 24 hr but dissipated by 48 hr. Rinsing the eyes after treatment was of questionable benefit. A single treatment of 0.5 mL neat SHC to rabbit skin produced negative results for all but a single animal, which had very slight erythema at the test site 48 hr after treatment. Guinea pigs failed to exhibit a sensitization response following repeated application of SHC. A single oral dose of 5 g SHC/kg body weight given to five male and five female F-344 rats and a single dermal dose of 2 g SHC/kg body weight applied to five male and five female NZW rabbits resulted in no deaths or signs of toxic stress. Five male and five female F-344 rats were exposed to 4.8 mg/L (near limit concentration) of aerosolized SHC for 4 hr. All male rats and four female rats survived. During exposure, the animals exhibited signs of eye and upper respiratory irritation.

Repeated-dose gavage studies on polychlorotrifluoroethylene acids.

C8 polychlorotrifluoroethylene (pCTFE) oligomers accumulate preferentially in the liver during long-term oral exposure and appear to be more hepatotoxic than C6 oligomers. A repeated-dose gavage study was initiated to determine the relative contributions of the corresponding C6 (trimer) and C8 (tetramer) acid metabolites to the toxicity of pCTFE in the male Fischer 344 rat. Test animals were dosed once per week for various time periods up to one year. A depression (p less than 0.05) in mean body weight occurred in the highest dose tetramer acid (2.16 mg/kg) group. An increase in hepatic peroxisomal beta-oxidation activity was found in the 2.16 mg pCTFE tetramer acid/kg dose group at the 3-, 6-, and 9-month sacrifice periods. An increase in relative liver weight was seen at all sacrifice periods in this dose group. Hepatocellular cytomegaly was a common finding in the higher dose tetramer acid groups but not in the trimer-treated rat groups.

Effects of a 13-week chloropentafluorobenzene inhalation exposure of Fischer 344 rats and B6C3F1 mice.

Chloropentafluorobenzene (CPFB) has been identified as a candidate simulant for nonpersistent chemical warfare agents. Acute toxicity studies have shown that CPFB has limited adverse effects on laboratory animals. A 21-day inhalation study of rats and mice to 2.5, 0.8, and 0.25 mg CPFB/liter resulted in reduced weight gain in male and female rats exposed at the high concentration only and identified the liver as a potential target organ. This multiconcentration inhalation study was designed to detect a no-observable-effect level associated with repeated exposure to CPFB. Male and female rats and mice were exposed to 250, 50, or 10 mg CPFB/m3 (0.25, 0.05, or 0.01 mg CPFB/liter) for 13 weeks. No treatment-related effects on body weight, clinical chemistries, mortality, absolute or relative organ weight or histopathology were noted.