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Interpretation of Urinary and Blood Benzene biomarkers of Exposure for Non-Occupationally Exposed Individuals
Citation:
Arnold, S. M., P. S. Price, S. H. Robison, M. F. HUGHES, AND P. J. Boogaard. Interpretation of Urinary and Blood Benzene biomarkers of Exposure for Non-Occupationally Exposed Individuals. Presented at 2009 Benzene Symposium, Munich, GERMANY, September 07 - 11, 2009.
Impact/Purpose:
This abstract describes the relationship between benzene air concentrations to published measurements of benzene biomarkers with a focus on non-occupational exposure. Urinary benzene and metabolite biomarkers correlate well with reported ambient air benzene levels.
Description:
Non-occupational exposure to benzene occurs primarily through inhalation ofair impacted by motor vehicle exhaust, fuel sources, and cigarette smoke. This study relates published measurements ofbenzene biomarkers to air exposure concentrations. Benzene has three reliable biomarkers ofexposure for non-occupationally exposed individuals: urinary benzene, urinary Sphenylmercapturic acid (SPMA), and blood benzene. Published linear regression equations for benzene and SPMA in urine were used to relate urinary measurements to average air concentrations,andfor comparisonto the USEPAreferenceconcentration (RiC)of0.030mg/nr' (9 ppb). The urinary benzene concentration relating to the USEPA RiC was 0.24 ngIL (range 0.04 to 0.46 ngIL). This compares to urinary benzene concentrations (central tendency values) reported in the literature ranging from 0.11 to 0.25 ngIL for non-smokers. As expected, the urinary benzene concentration for smokers was higher ranging from 0.19 to 1.78 ngIL. The urinary SPMA concentration relating to the RiC was 3.0 ug/g creatinine (cr.) (range = 0.1 to 6.8 ug/g cr.), This compares to urinary SPMA concentrations (central tendency values) reported in the literature ranging from 0.3 to 6.5 ug/g cr. for non-smokers. Similar to the results for urinary benzene, the urinary SPMA concentration for smokers was higher ranging from 0.5 to 9.9 ug/g cr. The results ofthis analysis indicate that for non-occupational exposure, urinary benzene and SPMA levels correlate well with reported ambient air benzene levels and non-smokers are generally at or below the urinary biomarker level corresponding to the USEPA RiC. An evaluation ofthe available blood benzene data is underway. The most recent CDC-NHANES data for blood benzene indicate levels of0.017 to 1.4 ng/ml, which are consistent with ranges previously reported in the literature. (This abstract does not represent US EPA policy) DOW RESTRICTED