Ana Bogadi-Sare1, Marija Zavalić, Rajka Turk. 1. Croatian Institute of Occupational Health, Division for Occupational Diseases and Industrial Toxicology, Zagreb, Croatia. hzmr@hzmr.hr
Abstract
BACKGROUND: A medical surveillance program of benzene-exposed workers has to be established in such a way as to observe early signs of benzene-induced cytopenia, pancytopenia, or leukemia. This study evaluates the utility of routine medical survey applied to benzene-exposed workers by analyzing the hematological, immunological, and cytogenetic assay results. METHODS: The results of a previous study of hematological, immunological, and cytogenetic assays in benzene-exposed workers (up to 15 ppm) are used to discuss medical surveillance program by defining the relationship between various benzene exposure concentrations and toxic endpoints. RESULTS: Exposure to benzene concentration lower than 5 ppm does not produce any abnormal hematological measurements. For benzene cumulative exposure above 100 (ppm-years), some blood indices [mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), band neutrophils] show significant differences in comparison to the control group. The incidence of dicentric chromosomes was higher and the level of B-lymphocytes was lower even with workers exposed to 5 ppm of benzene; correlation with exposure indicators was not found. CONCLUSIONS: The results suggest that peripheral blood indices, although not sensitive enough, are still the most suitable parameters in a health surveillance program applied to benzene-exposed workers. B-lymphocytes could be a promising indicator of the benzene-induced damage. Cytogenetic tests did not prove to be suitable. Further investigation of useful screening tests for health surveillance program of benzene-exposed workers is still required. Copyright 2003 Wiley-Liss, Inc.
BACKGROUND: A medical surveillance program of benzene-exposed workers has to be established in such a way as to observe early signs of benzene-induced cytopenia, pancytopenia, or leukemia. This study evaluates the utility of routine medical survey applied to benzene-exposed workers by analyzing the hematological, immunological, and cytogenetic assay results. METHODS: The results of a previous study of hematological, immunological, and cytogenetic assays in benzene-exposed workers (up to 15 ppm) are used to discuss medical surveillance program by defining the relationship between various benzene exposure concentrations and toxic endpoints. RESULTS: Exposure to benzene concentration lower than 5 ppm does not produce any abnormal hematological measurements. For benzene cumulative exposure above 100 (ppm-years), some blood indices [mean corpuscular volume (MCV), mean corpuscular hemoglobin concentration (MCHC), band neutrophils] show significant differences in comparison to the control group. The incidence of dicentric chromosomes was higher and the level of B-lymphocytes was lower even with workers exposed to 5 ppm of benzene; correlation with exposure indicators was not found. CONCLUSIONS: The results suggest that peripheral blood indices, although not sensitive enough, are still the most suitable parameters in a health surveillance program applied to benzene-exposed workers. B-lymphocytes could be a promising indicator of the benzene-induced damage. Cytogenetic tests did not prove to be suitable. Further investigation of useful screening tests for health surveillance program of benzene-exposed workers is still required. Copyright 2003 Wiley-Liss, Inc.