Human monitoring of exposure to organic solvents. I Benzene, phenol, toluene, cresols and xylenes

Abstract

In this report the conclusions of a literature study has been summarized concerning the monitoring of the general population to exposure to benzene-like solvents. Since the Dutch population is exposed to concentrations far below the ppm level, the conclusions on the suitability of biomarkers are based on the monitoring of organic solvents at low concentrations. The following compounds are considered in this study: benzene, phenol, xylenes, toluene and cresols. For exposure to benzene, the following biomarkers have been evaluated: benzene in blood, phenol, S-phenylmercapturic acid, trans,trans-muconic acid, 1,2,4-benzenetriol and catechol in urine. From these biomarkers only benzene in blood, S-phenylmercapturic acid and muconic acid are possibly interesting biomarkers of exposure. For monitoring of exposure to phenol, phenol sulphate and phenol glucuronide in urine have been evaluated as biomarkers but are not found to be suitable. For monitoring of exposure to toluene, toluene in blood, hippuric acid, para- and ortho-cresol, D-glucaric acid and retinol binding protein in urine have been evaluated. None of these parameters are found to be suitable as biomarker for toluene. For monitoring of exposure to cresols no suitable literature data have been found. For monitoring of exposure to xylenes, the biomarker methylhippuric acid in urine has been evaluated and found not to be suitable. The unsuitability of most of the biomarkers mentioned is caused by a combination of a too low sensitivity for variations in exposure in the actual concentration range, by individual variations (possibly polymorfisms) and by the disturbing influence of lifestyle and food components. Most of the mentioned biomarkers can be measured with routine like analytical methods. Therefore they can be of use in the assessment of exposures in the ppm concentration range. From the results of this literature study it is concluded that only for benzene suitable biomarkers have been found which meet the required criteria of specificity and selectivity.<br>