A comparative study of human levels of trichloroethylene and tetrachloroethylene after occupational exposure.

The rate of trichloroethylene (TRI) and perchloroethylene (PER) absorption was investigated in workers who were (1) occupationally exposed to TRI in four dry-cleaning shops (Group 1, n = 10) and (2) occupationally exposed to PER in one dry-cleaning shop (Group 2, n = 18). Concentrations of TRI and PER in blood were analyzed, and concentrations of trichloroethanol (TCE) and trichloroacetic acid (TCA) in blood and urine were analyzed. Results varied widely: PER was found in the blood of workers in group 1, but TRI was not detected in blood from any worker in group 2; most blood samples from group 2 workers did not contain a detectable quantity of TCE, and urine TCE concentrations in this group were very low. During the work week, a significant difference was found in group 1 for TRI in blood and TCE in blood and urine. In group 2, however, the only significant difference during the work week was for PER in blood. Therefore, the most reliable biological indicators for TRI and PER exposure are TCE in blood and PER in blood, respectively.

[Personal experience in biologic monitoring of exposure to organic solvents]. / Nasa iskustva u primjeni bioloskog monitoringa izlozenosti nekim organskim otapalima.

The paper describes our experience in the application of biological monitoring of occupational exposure to benzene, toluene, xylene, styrene, trichloroethylene and tetrachloroethylene. The importance of adequate selection of indicator, matrix and sampling time is pointed out. Own results are compared with the existing biological exposure indices. The need for actual and strict application of biological exposure indices is emphasized from the point of view of workers' health protection.

Qualitative color vision impairment in toluene-exposed workers.

OBJECTIVE: The aim of this study was to evaluate whether toluene, like many other organic solvents and solvent mixtures, could impair color vision. SUBJECTS AND METHODS: We investigated color vision impairment in three groups of workers, two groups occupationally exposed to toluene and a nonexposed group. The first exposed group, group E1, comprised 41 workers (median value of toluene in air 35.00 ppm, range 11.3-49.3 ppm) and the second exposed group, group E2, comprised 32 subjects (median value of toluene in air 156.00 ppm, range 66.0-250.0 ppm). The nonexposed group, group NE, comprised 83 subjects. Color vision was evaluated by the Lanthony D-15 desaturated test according to Verriest's classification: type I, loss in the red-green range; type II, loss in the blue-yellow and red-green ranges, and type III, loss in the blue-yellow range. Subjects were classified as dyschromates if specific acquired loss was determined in at least one eye. In both exposed groups, exposure was evaluated by measurement of the concentration of toluene in the ambient air and in the blood. In group E2, level of hippuric acid and orthocresol in urine after the work shift were also determined. The Mann-Whitney U-test, t-test, chi 2-test, and Spearman's rank correlation and multiple regression analysis were used for statistical analysis. RESULTS: Type III dyschromatopsia was detected in all groups examined: 26.6% of the workers in group NE, 31.7% of those in group E1, and 50% of those in group E2. As many as 15.6% of the workers in group E2, 4.8% of those in group E1, and only 1.2% of those in group NE had type II dyschromatopsia. A statistically significant difference in the prevalence of total dyschromatopsia (type III + type II) was established among the three examined groups together (chi 2 = 14.13; df = 2; P < 0.01), between group E2 and group E1 (chi 2 = 4.96; P < 0.05), and between group E2 and group NE (chi 2 = 12.50; P < 0.005), whereas no significant difference was found between groups E1 and NE. Type III dyschromatopsia was significantly correlated with age in group NE (P < 0.01) and in group E1 (P < 0.005). In group E2, both type II (P < 0.05) and type III dyschromatopsia correlated with toluene in ambient air and with the duration of exposure to toluene (both P < 0.005). In group E2, total dyschromatopsia correlated significantly with toluene in ambient air and in blood (both P < 0.05) as well as with hippuric acid in urine after the work shift (P < 0.001). CONCLUSION: This study suggests that toluene can impair color vision.

Assessment of colour vision impairment in male workers exposed to toluene generally above occupational exposure limits.

We investigated colour vision impairment in 45 male workers occupationally exposed to toluene (mean value of toluene concentration in ambient air = 119.96 ppm) and in 53 controls. Colour vision was evaluated by Lanthony-D-15 desaturated test and expressed as Age and Alcohol Intake Adjusted Colour Confusion Score (AACDS) or types of dyschromatopsia. Exposure was evaluated by measurement of toluene concentration in ambient air and blood, and hippuric acid and orthocresol determined in urine after the workshift. A statistically significant higher AACDS value was established in the exposed subjects compared to the controls (p < 0.0001). There was no significant difference between AACDS values on Wednesday morning compared to Monday morning. In the exposed group AACDS significantly correlated with the concentration of toluene in ambient air, concentration of toluene in blood and the concentration of hippuric acid in urine after the workshift (all p < 0.0001). Dyschromatopsias were detected in both groups, although no significant difference between groups was established. In the exposed group concentration of toluene in ambient air, alcohol intake and age explained 35.1%, concentration of toluene in blood, age and alcohol intake explained 19.9%, and concentration of hippuric acid in urine and age explained 19.2% of the variation in type III dyschromatopsia. Concentration of toluene in ambient air and age explained 28.3% of the variation in total dyschromatopsia, and concentration of hippuric acid and age explained 13.8%. In the control group, age and alcohol intake explained 19.6% of the variation in type III dyschromatopsia. In exposed workers a significant difference was found in the AACDS value compared to controls. However, no significant difference was found in the prevalence of colour vision loss in the yellow-blue and/or red-green axis. Based on the results of this study the authors conclude that the effect of toluene on colour vision can be chronic and that the possible reparation period in colour vision impairment is longer than 64 hours.