ESTIMATION OF REFERENCE VALUES FOR URINARY 1-HYDROXYPYRENE AND ALPHA-NAPHTHOL IN DANISH WORKERS

In order to assess environmentally and occupationally related exposure s to PAH compounds it is essential to have reference or normal values in human body fluids. The establishment of reliable reference interval s is an absolute pre-requisite in determining relationships between in ternal PAH exposure in humans and health effects in occupationally exp osed workers. In this context the estimation of the biological level o f PAH metabolites in urine from reference populations has become incre asingly important in the field of environmental and occupational toxic ology. The present study describes the calculation of tentative refere nce values for urinary l-hydroxypyrene on the basis of two reference p opulations and for urinary alpha-naphthol on the basis of one referenc e population in accordance with IFCC recommendations. The study subjec ts were 115 healthy male workers occupationally exposed to PAH at low levels and 121 reference subjects non-occupationally exposed to PAH. T entative reference values for urinary 1-hydroxypyrene were estimated. In addition, 236 healthy male workers were used to estimate tentative reference values for urinary alpha-naphthol. The reference populations were described by distribution free one-sided tolerance intervals. Th e 95% one-sided tolerance limit calculated for 1-hydroxypyrene in urin e was 0.053 mu mol/mol creatinine for non-occupationally exposed indiv iduals and 0.169 mu mol/mol creatinine for low level PAH exposed worke rs, with the coverage interval (95 +/- 4.5) percent at a probability o f 0.95. Thus, the probability was 0.975 that the tolerance interval in cluded at least 90.5% of the distribution. In addition, the probabilit y was 0.025 that the tolerance interval included > 99.5% of the popula tion. The tolerance interval for alpha-naphthol in urine was 5.665 mu mol/mol creatinine with the coverage interval (95 +/- 4.5) percent at a probability of 0.95.