反復暴露におけるトリクロロエチレンとその代謝物の体内動態 : 理論的アプローチ

抄録

In attempting to establish an excretory TLV for trichloroethylene, the rates at which trichloroethylene and its metablites accumulate in the body with increasing number of exposures and their plateau values attained after repetition of an infinite number of exposures were estimated theoretically with a mathematical model. After a single inhalation exposure to trichloroethyene is over its concentration in the blood, x, and the amount of its urinary metabolites, [D]^t₀ as a function of time t are expressed as a sum of three exponentials: x=A₁e-α_lt+A₂e-α₂t+A₃e-α₃t, and [D]^t₀=D₃(1-e-k₃t)-D₂(1-e-kBt)+D₁(1-e-k_At), where A₁-A₃ and D₁-D₃ are constants depending on the inhaled air concentration of trichloroethylene, and α₁-α₂ and k_A-k₃ rate constants. When the same degree of exposure is repeated for n consecutive days, the blood concentration, t hours after the nth day's exposure, becomes [numerical formula] and the amount of metabolites excreted in urine becomes [numerical formula] From the experimental results of a single human exposure reported previously, the concentration of trichloroethylene in the blood was predicted to change only to a negligible degree after repetition of an infinitive number of exposures, whereas the amount of total urinary metabolites was predicted to increase by twice as much as that excreted after the single exposure.