Urinary biomonitoring for evaluation of professional mixed exposure to volatile organic compounds : a field intervention

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, 7 interventions took place in different factories.

This poster presents the results obtained in a French factory producing paint, resin and varnish, in which chloroform, toluene, ethylbenzene, styrene and xylenes were regularly used. Six units took part in the study. About 30 “exposed” workers and 10 controls (5 smokers and 5 non-smokers) gave urine samples before and after work shift for three days. They were also asked daily about their activities, the products and the individual protections used, and 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. Chlorinated compounds aren’t present in tobacco smoke. The excretion observed is therefore independent from the smoking habits.

Ethylbenzene and xylenes urinary excretions were significantly higher after the work shift than before, what highlights the occupational origin of the exposure. End shift excretions are characteristic of occupational exposure and are therefore used to compare the results of the different units. For aromatic compounds, excretions are only compared to those of smoking controls, in order to free from the possible smoking of “exposed” workers. Several units showed statistically significantly higher end shift excretion than those of the controls for chloroform, ethylbenzene, xylenes and styrene). Nevertheless, for chloroform and styrene, the observed excretions remained quite low.