STUDY ON URINE BORON REFERENCE VALUES OF JAPANESE MEN - USE OF CONFIDENCE-INTERVALS AS AN INDICATOR OF EXPOSURE TO BORON-COMPOUNDS

A simple and rapid method for the determination of urine boron by indu ctively-coupled plasma argon emission spectrometry (ICPAES) has been d eveloped to establish boron exposure guidelines. After Ii-fold dilutio n in 18.25 MR cm ultra-pure water and vigorous shaking, urine may be d irectly injected into the spectrometer, providing accurate and reprodu cible results. We report the results obtained with urine samples obtai ned from a group of male Japanese electronic workers (n = 102) who had not been exposed to boron; boron concentrations were corrected with u se of a specific gravity of 1.024 g/ml. The frequency distribution res ulted in a log-normal distribution diagram for anatomical spread. The geometric mean values for urine boron in the non-exposed workers was 7 98.0 mu g/l, while the confidence interval (C.I.) was between 398.1 an d 1599.6 mu g/l. Taking into consideration the short biological half-l ife of boron and its major excretion route via urine, urine was consid ered to be a suitable means for monitoring of exposure to this element . We conclude that the guidelines established by determining boron ref erence values are useful for the protection of individuals exposed to boron in their working environments. (C) 1998 Elsevier Science B.V. Al l rights reserved.