Biological monitoring of experimental human exposure to hydrocarbon solvent mixtures

Abstract

The aim of the study was to develop and to validate a suitable analytical method in order to assess the internal exposure of persons to commercial products of hydrocarbon solvent mixtures (HSM). Twenty healthy volunteers were exposed to vapours of five commercial HSM for 8 h at 200–1000 mg/m 3 air. Aromatic-rich, aromatic-poor and aromatic-free HSM were used, as well as isohexane and technical hexane mixtures. A total of 300 exposures were carried out at rest or with an exercise period of 10 min/h at 50 and 75 W. Blood samples for the determination of the HSM were collected before and immediately after exposure. They were analyzed with a headspace analyzer by gas chromatography and mass spectrometry. The analytical method has detection limits of 2–50 μg HSM/L blood. With this method we obtained intra- and interassay variation coefficients of 3.7–15.1%, at concentrations of 53–1500 μg HSM/L blood. The mean values of the HSM of the 20 volunteers after 8 h range between 89 μg/L (technical hexane-mixture) and 1369 μg/L blood (aromatic-free HSM) at rest. Physical exercises of 50 and 75 W, respectively, lead to a significant increase of the blood-concentrations by mean factors between 1.2 and 1.9 for the five HSM. In conclusion, our results demonstrate that physical activity should be considered in the setting of occupational exposure limits.