Toxicological assessment of benzophenone as the basis for its hygienic rationing in the air of the working area

For the purpose of hygienic rationing of benzophenone in the air of the working zone its toxic properties have been studied. DL₅₀ for male rats, male and female mice amounted to 3000, 2000 and 1300 mg/kg, respectively. Benzophenone refers to moderately hazardous substances (hazard class III). The clinical picture of the acute poisoning with this substance was characterized by the low mobility, myorelaxation, shaky gait, breathing loss, weakened response to external stimuli and death on days 1 to 3 after the poisoning. There were no significant differences in the species and gender susceptibility of animals to the substance: coefficients of species differences and gender susceptibility ≈1.5. Benzophenone has an average cumulative capacity: a cumulation factor accounts for 3.2. It does not have a local irritant effect on the skin and skin-resorptive effect. It has a mild irritant effect on the mucous membranes of the eyes. There was no sensitizing effect in benzophenone: the specific leukocyte lysis reaction, the specific agglomeration of leukocytes and the eosinophil content in the blood of the experimental guinea pigs did not differ significantly from the control. After single 4-hour inhalation primers of benzophenone at concentrations of 35.2, 94.6 and 200 mg/m³, there were no violations of the synthetic and enzymatic functions of the liver. The threshold of acute inhalation action is 94.6 mg/m³ (for decreasing body temperature, increasing the summation threshold and leukocytosis). Approximate safe level of exposure to benzophenone in the air in the working area is 2 mg/m³ (aerosol).