Occupational exposure to dioxins by thermal oxygen cutting, welding, and soldering of metals.

This paper focuses on one aspect of occupational dioxin exposure that is novel and unexpected. Exposures in excess of the German threshold limit value of 50 pg international toxicity equivalent (I-TEQ)/m3 are very frequent, unpredictable, and sometimes very high--up to 6612 pg I-TEQ/m3--during thermal oxygen cutting at scrap metal and demolition sites. The same procedure involving virgin steel in steel trade and mass production of steel objects gave no such evidence, even though no final conclusions can be drawn because of the low number of samples analyzed. Low dioxin exposures during inert gas electric arc welding confirm previous literature findings, whereas soldering and thermal oxygen cutting in the presence of polyvinyl chloride give rise to concern. The consequences of occupational dioxin exposure were studied by analysis of the dioxin-blood concentration, the body burden, of men performing thermal oxygen cutting at scrap metal reclamation and demolition sites, in steel trade and producing plants as well as for industrial welders and white-collar workers. The results concerning body burdens are in excellent agreement with the dioxin exposure as characterized by dioxin air concentration in the workplace. The significant positive correlation between duration and frequency of performing thermal oxygen cutting at metal reclamation and demolition sites expressed in job-years and dioxin body burden speaks for the occupational origin of the observed overload after long times. The results reported here lead to consequences for occupational health, which are discussed and require immediate attention.

Genotoxic risk for humans due to work place exposure to ethylene oxide: remarkable individual differences in susceptibility.

Single strand breaks of DNA of peripheral mononuclear blood cells from 97 male and female workers occupationally exposed to ethylene oxide were analysed by the alkaline elution method. These individuals were occupied with the sterilization of medical devices in hospitals and in commercial plants. Ethylene oxide in the air of the working areas was detected up to a maximal concentration of 16.5 mg/m3 calculated as 4-h time-weighted average (4h TWA). Mean value was 1.47 +/- 0.52 mg/m3 (1 mg/m3 = 0.55 ppm). Compared to the mean elution rate of the DNA from non-smoking workers exposed to air concentrations of ethylene oxide below the detection limit of 0.1 mg/m3 (4h TWA) the non-smokers working in rooms with a concentration of ethylene oxide between 0.5 mg/m3 and 2 mg/m3 showed a statistically significant (P < 0.05) 119% higher mean elution rate and even for the non-smokers exposed to 0.1-0.5 mg/m3 of ethylene oxide a statistically significant (P < 0.05) 53% higher mean elution rate was observed. For smokers a similar tendency was found but the increase in elution rates in response to the external exposure was smaller than in non-smokers and no statistical significance was obtained. According to their sensitivity to ethylene oxide the non-smoking workers could be classified into two subpopulations. In the majority of the non-smokers (67%) approximately 5-fold more DNA strand breaks were induced by ethylene oxide than in the other non-smokers. A lowest detectable effect level could only be specified for non-smokers. (ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic tests in enzyme allergy.

BACKGROUND: Allergies to enzymes occur frequently in enzyme manufacturing plants. In epidemiologic studies the number of exposed subjects with symptoms is considerably higher than the number of sensitizations as assessed by skin tests or RAST. It was the aim of this study to evaluate the sensitivity and specificity of skin prick tests, enzyme allergosorbent test, and immunoprint with enzymes by using the results of bronchial provocation tests as the "gold standard." METHODS: We performed 82 bronchial provocation tests with nine different enzymes in 42 chemical plant workers, all of whom had reported work-related symptoms. All tests with the exception of bronchial provocation tests were also performed in 10 atopic and 10 healthy control subjects. RESULTS: Thirteen workers showed positive results to bronchial provocation tests (50% or greater fall in specific airway conductance) with an enzyme at a maximal concentration of 10 mg/ml. Equivocal test results, that is, tests with a 30% or greater and less than 50% fall in specific airway conductance were seldom. Skin prick tests with nondialyzed aqueous enzyme extracts at a concentration of 10 mg/ml yielded a sensitivity of 100% and a specificity of 93%. Control subjects had no cutaneous reactions to enzymes. Discrepancies between skin tests and bronchial provocation tests occurred in 5 of 82 tests, all with a positive skin test and a negative bronchial provocation test. False-positive skin tests were considered more likely in four subjects and a false-negative bronchial challenge more likely in one case. Enzyme allergosorbent test was 62% sensitive and 96% specific, and atopic control subjects showed positive results in two cases. Results of immunoprint with amylase showed one main band at pH 3.4; this band was also found in exposed subjects without further signs of sensitization, but was not found in control subjects. All but one person with positive results to bronchial provocation tests with enzymes showed bronchial hyperresponsiveness. We identified 13 subjects with bronchial hyperresponsiveness, but without occupational allergy: five of these had sensitizations to nonoccupational allergens and the remainder showed bronchial hyperresponsiveness without any detectable cause. CONCLUSIONS: Occupation-related symptoms were not indicative of occupational allergy. Bronchial provocation tests and skin prick tests with nondialyzed aqueous enzyme extracts were appropriate techniques for the diagnosis of enzyme allergy.

Prevalence of respiratory allergy in a platinum refinery.

In a cross-sectional study, 65 workers in the chemical industry with exposure to platinum salts were investigated with regard to the prevalence to allergic respiratory tract diseases. A respiratory questionnaire, a skin-prick test with K2PtCl6 and environmental allergens, determination of total IgE, platinum-specific IgE and histamine release in basophilic granulocytes and lung function tests were applied before and after a Monday shift and after a Friday shift. Work-related symptoms of respiratory allergy were present in 23% of all workers, but were significantly more frequent in the most exposed group in the platinum refinery (52.4%). Of all workers, 18.7% had a positive skin-prick test with platinum salt. As compared to the other workers, the workers with work-related symptoms of respiratory allergy had significantly more positive skin-prick tests (64.3%) and a higher total IgE and platinum-specific IgE; they did not, however, show higher histamine release. In the course of the week, a significant fall in lung function, namely in FEV1 and FEF25, was recorded in the group of workers with work-related symptoms.