Metabolism of trichloroethylene and tetrachloroethylene in human subjects

Abstract

A linear correlation exists between the trichloroethylene concentration in the work environments and the level of total trichloro compounds in the urine of the workers, as expressed by the equation: Gamma = 7.25=chi + 5.5, where Gamma is trichloroethylene in air (ppm) is Chi is total trichloro compounds in urine (mg/l). Trichloroethanol level is also linearly related to trichloroethylene concentration, while trichloroacetic acid level deviates from the linear relation when trichloroethylene level exceeds 50 ppm. In the case of tetrachloroethylene exposure, both trichloroethanol and trichloroacetic acid levels, and consequently the total trichloro compound level, reach a plateau at tetrachloroethylene level well below 100 ppm. The mean urinary biological half-life is 41 hr for trichloroethylene and 144 hr for tetrachloroethylene. The two values are the largest of the values so far obtained with organic solvents. The respiratory half-life is shorter than the urinary half-life, both in richloroethylene and in tetrachloroethylene. Applications of the urinalyses in clinical cases are described. In one case of trichlorethylene dependency, a longer urinary half-life of 73 hr was observed. An automated system is presented for the determination of total trichloro compounds in human urine. The system can analyze the samples at the rate of 20 samples per hour with an accuracy comparable to that of the time-consuming manual analysis.