Biological monitoring for exposure to volatile organic compounds (VOCs)

This paper deals with the appropriate application of biological monitoring (BM) for exposure to volatile organic compounds (VOCs). Sampling guidelines , approved analytical procedures, quality control systems, detailed aspects for the interpretation of biomonitoring data, a compilation of internation al biological action values for VOC exposure at the workplace (e.g., BAT, B EI(R)), and state of the art reference values are outlined or referred to i n this review for recommendation as guidelines for health professionals in occupational and environmental settings. VOCs are frequently encountered at the workplace, in daily routines and wid ely used consumer products. They cover a broad spectrum of chemical classes with different physicochemical and biological properties. Inhalation is a prominent route of exposure due to their volatility but many VOCs can quite readily be absorbed through the skin. BM allows assessment of the integrat ed exposure by different routes including inhalation and concomitant dermal and oral uptake-a helpful tool for relating exposure to body burden and po ssible health effects. Because of the different toxicological profiles of V OCs, no uniform approach for BM can be recommended. VOCs in blood and urina ry VOC metabolites are most often applied for BM. Limit values for workplac e exposure have been established for many VOCs. In this field, profound ana lytical methodology and extensive experience exist in numerous internationa l scientific laboratories for reliable routine application. Contamination a nd loss of VOCs during specimen collection, storage and sample treatment, a nd applied calibration procedure an the most important uncertainties for an alytical quantification of VOCs in blood. For interpretation of the analyti cal results appropriate time of sampling, according to toxicokinetics of th e compound, is crucial due to VOC elimination with short but differing biol ogical half-lives. Lifestyle factors (such as smoking habits, alcohol consu mption, and dietary habits), workload, personal working habits, exposure to VOC mixtures and endogeous factors (as genetic polymorphism for VOC metabo lizing enzymes, body mass) contribute to BM results and have to be consider ed in detail. Future analytical work should focus on the improvement of ana lytical methodology of VOC determination in body fluids at low-level enviro nmental exposure and evaluation of corresponding reference intervals.