Application of statistical models to estimate the correlation between urinary benzene as biological indicator of exposure and air concentrations determined by personal monitoring.

This study evaluated the correlation between benzene in urine and in workplace air at low airborne benzene levels (below 1 ppm). Eleven workers were monitored over a period of 1-4 days at a petrochemical plant in Italy; samples of end-of-shift urine and workplace air were analyzed for benzene. A significant correlation, with a coefficient of determination R(2)=0.63, was found between urine and airborne benzene, confirming the results of previous studies. Two different statistical models were utilized to estimate urine benzene values of 9-16 microg/L corresponding to the American Conference of Governmental Industrial Hygienists' threshold limit value (TLV) of 0.5 ppm in workplace air. Not withstanding the variability inherent to biological monitoring, the results suggest application of biomonitoring as a trigger for identification of lower exposure level below, but approaching the TLV. Additionally, the proposed benzene biomonitoring may be useful in evaluating PPE effectiveness and use characteristics as well as dermal contribution to total exposure.