Cardiac arrhythmia in refrigerator repairmen exposed to fluorocarbons.

A field study of 89 refrigerator repairmen was carried out to ascertain whether occupational exposure to fluorocarbons induces cardiac arrhythmia. The concentrations of fluorocarbons in the breathing zones and the heart activity were recorded simultaneously. Most cooling systems contained FC 12 or FC 22. The highest level recorded in one minute was 14,000 ppm and the highest time weighted level during eight hours was 280 ppm. Two types of arrhythmia were recorded, ectopic beats and sudden bradycardia. A within subject comparison design was applied and the main parameter was the difference in arrhythmia frequencies between exposed and unexposed periods. No appreciable differences between exposed and unexposed periods and no consistent dose effect relations were observed, although subjects in the medium exposure category showed a difference of borderline significance (Wilcoxon's test: p = 0.05, one tailed). The frequencies of arrhythmia when unexposed were somewhat higher than previously reported. Misclassification of the exposure and the possible confounding effect of physical workload and psychological strain may have obscured a causal relation and therefore a minor effect cannot be ruled out. The results do not support the notion that fluorocarbons induce cardiac arrhythmia in occupationally exposed refrigerator repairmen.

Diazo-positive metabolites in urine from workers exposed to aromatic nitro-amino compounds.

The amount of diazo-positive compounds in urine from workers at a chemical plant producing pharmaceuticals and explosives was determined in samples collected after work and after a holiday. Forty-five persons working with aromatic nitro-amino compounds (ANA) showed a statistically significant (p less than 0.01) increase in the exposed samples (1.21 +/- 1.40 mmol/mol creatinine) compared to the unexposed samples (0.56 +/- 0.31 mmol/mol creatinine). No increase in the level of diazo-positive metabolites was found in the 25 workers not exposed to ANA compounds. In a follow-up study, 32 trinitrotoluene (TNT) workers were divided into three exposure categories and seemed to show a dose-dependent increase in the level of urinary diazo-positive metabolites. However, there was a considerable interindividual variation. The method seems suitable for the biological assessment of exposure to ANA compounds--at least on a group level. This may be valuable, especially in situations where significant dermal uptake is expected.