Dose‐excretion relationship in tetrachloroethylene‐exposed workers and the effect of tetrachloroethylene co‐exposure on trichloroethylene metabolism

Abstract

Personal monitoring of 8-hour time-weighted average intensity of exposure with diffuse samplers and analysis of shift-end urine for total trichloro-compounds (TTC) and other metabolites were conducted in two groups of workers in China, one (121 subjects) exposed to tetrachloroethylene (TETRA) alone, and the other (38 subjects) exposed to a mixture of TETRA and trichloroethylene (TRI). Urinalysis was also performed on samples from 103 non-exposed controls. A linear exposure-excretion relationship could be observed in both groups of workers. Comparison of these results with those of Japanese TETRA-workers suggested the presence of ethnic difference in TETRA metabolism. Urinary metabolite levels were markedly lower in the mixed (TETRA + TRI) exposure group as compared to previous findings in a group exposed to TRI alone. The observation indicates that metabolism of TRI is suppressed by the co-exposure to TETRA in humans.

Monitoring of occupational exposure to tetrachloroethene by analysis for unmetabolized tetrachloroethene in blood and urine in comparison with urinalysis for trichloroacetic acid

“…For determination of TETRA in blood and in urine, head-space GC methods were used in common. The GC method was used for urinary TCA determination by and in the present study, whereas colorimetry was used in the case of Seiji et al (1989). The present study, however, made it clear that the two methods give essentially the same results (Fig.…”

“…summarized their observation in ®eld surveys in dry-cleaning and metal cleaning workshops, that the TCA level in a urine sample collected at the end of a working week will be 6.1 lmol/mmol creatinine when TWA TETRA exposure is at 50 ppm; a linear extrapolation to 25 ppm TETRA gives a value of 4.4 mg TCA/g creatinine when molecular weights of 163.40 and 113.12 for TCA and creatinine, respectively, are considered. Seiji et al (1989) made a ®eld survey of dry-cleaning workshops in China; the regression equation as a summary of the survey suggests that TCA in end-of-shift urine samples from workers exposed to 25 ppm TETRA would be 2.9 mg/l or 2.4 mg/g creatinine. In comparing the present observation with BEI Ò (ACGIH 1991) for TETRA in blood and also with the estimation of Lauwerys et al (1983), it is necessary to make a correction for the dierence in sampling time, i.e., at the end of the shift in the present study, and prior to the shift in the cases of ACGIH (1991) and Lauwerys et al (1983).…”

Green Chemistry in Urinalysis for Trichloroethanol and Trichloroacetic Acid as Markers of Exposure to Chlorinated Hydrocarbon Solvents

“…Until very recently, trichloroethylene (TRI) 3,4) and 1,1,1-trichloroethane (methylchloroform or MC) [5][6][7] had been among the most popular chlorinated hydrocarbon solvents, and tetrachloroethylene (TETRA) is still widely used for cleaning of clothes [8][9][10] and other materials. Trichloroethanol (TCE) and trichloroacetic acid (TCA), and therefore total trichlorocompounds (TTC) as the sum of the two, are major metabolites in urine of workers exposed to these solvents [11][12][13] .…”

Ethnic differences in biological monitoring of several organic solvents II. A simulation study with a physiologically based pharmacokinetic model

“…Although some studies mention the possibility of ethnic dierences based on observations in workers (Inoue et al 1986(Inoue et al , 1988Jang et al 1993;Seiji et al 1989), ethnic dierences usually have not been considered in the application of biological monitoring. Ethnic dierences have been reported in the kinetics of several organic solvents between Orientals and Caucasians in an experimental exposure study .…”