Biological monitoring of exposure to several volatile organic compounds by measuring their residual fraction in the urine: feasibility study

Multi-exposures to chemicals are frequent in the workplace, and represent a serious current issue. According to the results of the Sumer 2003 study, 20 % of employees could be exposed to at least five chemical agents. Among the chemical compounds known to be hazardous to health, numerous volatile organic compounds (VOCs) are commonly used in industry and are classed among the carcinogen, mutagen or toxic to reproduction compounds (CMR), and as ototoxic compounds. To assess occupational exposure to VOCs, an alternative way to monitor the urinary excretion of the relevant metabolites is to measure the residual concentrations of non-metabolised VOCs in the urine. According to the literature, one technique, Headspace, has already been applied successfully in biological monitoring. In particular, it avoids the prior and generally fastidious urinary sampling treatments, a step often necessary when employing traditional techniques.
This approach, already used in the laboratory in a previous study, proved promising for monitoring exposures to solvents of a not very hydrosoluble nature, like toluene. The study will consist in validating this technique for carrying out, in a single analysis, the monitoring of employees potentially and simultaneously exposed to several VOCs. The industrial sectors where co-exposures may exist will be identified, and a list of hazardous VOCs, chosen from among the CMR or ototoxic substances, drawn up. The analytical method will firstly be optimised on spiked urines using the equipment currently available in the laboratory. This will then be tested on urines sampled from employees actually exposed. This method of simultaneous urinary analysis of VOCs of differing structures and chemical properties could be proposed to occupational health specialists as an alternative tool, complementary to atmospheric monitoring, for assessing occupational multi-exposures.