A novel alternative to environmental monitoring to detect workers at risk for beryllium exposure-related health effects

The purpose of this study was to describe a methodology for surveillance and monitoring of beryllium exposure using biological monitoring to complement environmental monitoring. Eighty-three Israeli dental technicians (mean age 41.6 ± 1.36 years) and 80 American nuclear machining workers (54.9 ± 1.21 years) were enrolled. Biological monitoring was carried out by analyzing particle size (laser technique) and shape (image analysis) in 131/163 (80.3%) induced sputum samples (Dipa Analyser, Donner Tech, Or Aquiva, Israel). Environmental monitoring was carried out only in the United States (Sioutas impactor, SKC, Inc., Eighty Four, Pa.). Pulmonary function testing performance and induced sputum retrieval were done by conventional methods. Sixty-three Israeli workers and 37 American workers were followed up for at least 2 years. Biological monitoring by induced sputum indicated that a >92% accumulation of <5 μm particles correlated significantly to a positive beryllium lymphocyte proliferation test result (OR 3.8, 95% CI 1.2-11.4, p = 0.015) among all participants. Environmentalmonitoring showed that beryllium particles were <1 μm, and this small fraction (0.1-1 μ) was significantly more highly accumulated in nuclear machining workers compared to dental technicians. The small fractions positively correlated with induced sputum macrophages (r = 0.21 p = 0.01) and negatively correlated with diffusion lung carbon monoxide single breath (DLCO-SB r = 0.180 p = 0.04) in all subjects. Years of exposure were positively correlated to the number of accumulated particles 2-3 μ in diameter (r = 0.2, p = 0.02) and negatively correlated to forced expiratory volume in one second/forced vital capacity findings (r = -0.18, p = 0.02). DLCO was decreased in both groups after two years of monitoring. Biological monitoring is more informative than environmental monitoring in the surveillance and monitoring of workers in beryllium industries. Induced sputum is a feasible and promising biomonitoring method that should be included in the surveillance of exposed workers.