Urinary biomonitoring for evaluation of professional mixed exposure to volatile organic compounds

Mixed exposures to chemical products often happen during work time and they are topical issues for occupational health. According to the 2003 Sumer Survey, 20% of French workers are exposed to 5 chemicals at least. Among hazardous chemicals, many volatile organic compounds (VOCs) widely used in industry are listed as CMR (carcinogenic, mutagenic or toxic to reproduction compounds) or considered as ototoxic compounds.
In order to evaluate occupational exposures to VOCs, analysis of unmetabolized VOCs in urine can be an interesting way of monitoring their excretion, which is traditionally done using urinary relevant metabolites.
Headspace analysis has the asset to avoid time-consuming preliminary samples processing, which are usually required by metabolites monitoring. Using dynamic Headspace and gas chromatography linked to a mass spectrometer leads to an optimized sensitivity, which is required by this kind of trace analysis. Headspace has been already used to assess occupational exposure to VOCs (Ducos et al., 2008), but only few methods have been developed in case of mixed exposures (Fustinoni et al., 1996 ; Kramer Alkade et al., 2004), only on a single chemical family. It was chosen to develop an analytical headspace method to analyze in a single run aromatic hydrocarbons as well as chlorinated compounds. The assessed VOCs are benzene, toluene, ethylbenzene, xylenes, styrene, dichloromethane, chloroform, trichloroethylene, tétrachloroéthylène. As it is almost impossible to find factories using all the compounds investigated, the field study involves firms where workers are potentially exposed to two VOCs at least. Until now, 3 interventions took place, two in a refinery plant and one in a furniture factory. About 30 workers (plus controls) gave urine samples before and after work shift for five days. They were also asked about their smoking habits.

In case of low exposures, smoking is the most important parameter. Indeed, the tobacco smoke contains a lot of aromatic hydrocarbons, most especially benzene and toluene. In the furniture factory, where toluene, xylenes and ethylbenzene were used as paint and varnish components, exposure was found to be statistically significative compared to controls, even if smoking was the main factor influencing urinary excretion level.

In the refinery plant, two interventions took place. The first one occurred during a standard week of work, and the second one during a major clean-up week, when activities were supposed to be more exposing. Chloroform, benzene, toluene, ethylbenzene and xylenes were found in workers urines. During the standard week, one activity was found to be particularly exposing to benzene and xylenes, and a second one to chloroform.
During the clean-up week, exposures were more important and two additional activities showed significative exposure to benzene.
Ducos, P., Berode, M., Francin J.M., Arnoux C., Lefèvre C. (2008). Int Arch Occup Environ Health, 81 (3), 273-284.