Gerhard Triebig

Intervention study on acquired color vision deficiencies in styrene-exposed workers.

The main aim of the study was to examine the possible effects of occupational exposure to styrene on color vision function and the course after reduction of exposure. Color vision function was examined in 22 styrene-exposed laminators and 11 control subjects at a boat manufacturing plant. The Lanthony D-15 desaturated panel was used to test acquired dyschromatopsia. In all, six examinations were performed: Monday morning and Thursday afternoon of the same week, before and immediately after a vacation of 4 weeks (altogether, phase 1), and approximately 10 months later (phase 2), after the exposure level of styrene had been reduced. Styrene uptake was objectified by biological monitoring measuring the metabolites mandelic acid and phenylglyoxcylic acid in urine samples taken on Thursday afternoon. In both Thursday examinations, styrene-exposed workers had higher color confusion index (CCI) values compared with controls, which indicated quantitative color vision loss. After an exposure-free period of 4 weeks, a significant decrease of CCI values to normal range was found in laminators. Reexamination 10 months later showed also lower CCI values in exposed workers, indicating a dose–effect relationship. Abnormal CCI values occurred primarily in subjects with an excretion of approximately 500 to 600 mg mandelic acid plus phenylglyoxcylic acid per gram creatinine or more. We concluded that styrene-induced color vision dysfunction is reversible after an exposure-free interval of 4 weeks. The current Biological Tolerance Value of 600 mg mandelic acid plus phenylglyoxcylic acid per gram creatinine, as used in Germany, protects styrene-exposed workers from this subclinical effect.

Association Between Genetic Polymorphisms in Styrene-Metabolizing Enzymes and Biomarkers in Styrene-Exposed Workers∗

Single-nucleotide polymorphisms (SNP) in genes of styrene-metabolizing enzymes could modulate biomarker concentrations in blood or urine after exposure to styrene. Ten SNP were analyzed to study their influence on styrene-specific biomarkers in 89 workers of a fiber-reinforced plastic boat building factory. The internal styrene body burden was analyzed in post-shift blood and urine samples. External styrene exposure was measured by passive samplers. Spearman rank correlations between styrene exposure and biomarkers were calculated and distributions of biomarkers were checked for lognormality. Mixed linear models were applied to analyze the influence of genotypes and styrene exposure, on styrene in blood (Monday and Thursday post-shift) and on phenyglyoxylic acid (PGA; adjusted for day of measurement, Monday to Thursday) due to a lognormal distribution, smoking (current, not current), and use of respirators. Stratified analyzes for workers without and with different types of respirators were also performed. The models of both the subgroups revealed a significant influence dependent on the respirator type that workers used for inhalation protection. An influence of the external styrene concentration on the urinary PGA concentration was not observed. After implementation of the SNP into the model significant lower adjusted means of urinary PGA concentrations were found for GSTP1 105IleVal and CYP2E1 –71TT. For styrene levels in blood no significant effect was observed. A significant influence on styrene levels in blood was correlated with external styrene concentration only in workers without use of respirators. The effects of two SNP on urinary PGA decrease indicated a limited modulating SNP effect. The most effective prevention for styrene exposure was obtained with the wearing of respirators.

Exposure study to examine chemosensory effects of ɛ-caprolactam in healthy men and women

Abstract Context: ε-Caprolactam is an important industrial chemical with a relatively low human toxicity; of importance is the irritations that occur after exposure to ε-caprolactam as aerosols or vapors. Objective: The aim of this study was to examine symptoms and objective effects, which occur on the mucous membranes of the eyes and the upper respiratory tract. Methods: A total of 52 healthy volunteers (26 women and 26 men, aged between 19 and 50 years) were exposed by random to different ε-caprolactam concentrations (0.05, 0.5 and 5.0 mg/m³) and the control condition (0.0 mg/m³) for 6 h on four consecutive days. Eye blinking frequency, tear film break-up time, eye redness, nasal flows and resistance, olfactory function as well as total protein and interleukin-8 in nasal lavage fluid were determined daily before, during and after exposure. Questionnaires were used to record both subjective symptoms and personality factors. Results: There were no significant specific effects on the subjective and objective endpoints examined. Statistical analysis yielded no evidence of concentration-response relationships. Evaluation of olfactory symptoms showed that the duration of the stay in the chamber and not the ε-caprolactam concentration was decisive for the perception of “impure air”. Personality factors had no significant influence on the reported symptoms. Conclusions: Exposure to ε-caprolactam concentrations of 5.0 mg/m³ at maximum for 6 h did not cause chemosensory effects on the upper respiratory tract or eyes of healthy volunteers. Therefore, the concentration of 5.0 mg/m³ corresponds to the No Observed Adverse Effect Level (NOAEL).

Aktuelle Aspekte zur Krebsfrüherkennung bei Beschäftigten mit Exposition gegenüber krebserzeugenden Arbeitsstoffen

Klinisches Bild und Verlauf berufsbedingter Krebskrankheiten unterscheiden sich generell nicht von bosartigen Krankheiten anderer Genese. Da Malignome in fortgeschrittenen Krankheitsstadien nach wie vor eine ungunstige Prognose aufweisen, haben aus arbeitsmedizinischer Sicht effiziente Masnahmen zur Pravention und Krebsfruherkennung eine hohe Prioritat. Hierbei stellt die Identifizierung von so genannten Risikopersonen, d.h. Beschaftigten mit relevanten Expositionen gegenuber chemischen oder physikalischen Kanzerogenen am Arbeitsplatz, eine vordringliche Herausforderung an die arbeitsmedizinische Vorsorge dar. Ziel des Kapitels ist es daher, anhand der aktuellen Kenntnisse uber krebserzeugende Arbeitsstoffe Personen mit einer erhohten Gesundheitsgefahrdung zu definieren und im Weiteren auf die Moglichkeiten von Pravention und Fruherkennung einzugehen.