Suchergebnisse

Abstract
The present research project is aimed at providing an accurate low-dose benzene exposure assessment method, by validating diffusive monitoring techniques for benzene personal exposure measurements at workplaces where low benzene concentrations are expected. The experiments have been conducted following the EN 838:2010 standard in the range of 16 to 320 µg/m3 (0.005 to 0.1 ppm). The study is part of the Concawe project on "accurate low-dose benzene exposure assessment, dose-specific metabolism and potential early markers" aiming at developing a methodology to monitor benzene exposures at low levels in environments typical of the petroleum industry. Diffusive sampling offers a reliable alternative to pumped sampling methods, intrinsic safety in potentially explosive atmospheres, lightness and ease of use. The tested diffusive sampler is radiello™, two alternative configurations of the sampler can be used: RAD130, packed with activated charcoal, suitable for solvent desorption and analysis by HRGC-FID, and RAD145, packed with graphitised charcoal, suitable for thermal desorption and analysis by HRGC-MS. For both configurations the sampler performances have fulfilled all requisites of the EN 838:2010 standard, in particular: bias due to the selection of a non-ideal sorbent is lower than 10% (no significant back diffusion of benzene due to concentration change in the atmosphere); bias due to storage of samples for up to 2 months is lower than 10%; nominal uptake rate for benzene on RAD130 is 74.6 ml/min and on RAD145 is 32.3 ml/min; expanded uncertainty of the sampling and analytical method is 20.2% on RAD130 and 26.1% on RAD145.

Background: The main anthropic sources of exposure to airborne benzene include vehicular traffic, cigarette smoke, and industrial emissions. Methods: To detect early genotoxic effects of environmental exposure to benzene, we monitored environmental, personal, and indoor airborne benzene in children living in an urban area and an area near a petrochemical plant. We also used urinary benzene and S-phenylmercapturic acid (S-PMA) as biomarkers of benzene exposure and urinary 8-hydroxydeoxyguanosine (8-OHdG) as a biomarker of early genotoxic effects. Results: Although always below the European Union limit of 5 μg/m(3), airborne benzene levels were more elevated in the indoor, outdoor, and personal samples from the industrial surroundings compared to the urban area (p = 0.026, p = 0.005, and p = 0.001, respectively). Children living in the surroundings of the petrochemical plant had urinary benzene values significantly higher than those from the urban area in both the morning and evening samples (p = 0.01 and p = 0.02, respectively). Results of multiple regression modelling showed that age was a significant predictor of 8-OHdG excretion, independent of the sampling hour. Moreover, at the low exposure level experienced by the children participating in this study, neither personal or indoor airborne benzene level, nor personal monitoring data, affected 8-OHdG excretion. Conclusions: Our results suggest the importance of biological monitoring of low-level environmental exposure and its relation to risk of genotoxic effects among children.