Environmental and biological limit values and reference values for micropollutants in life ambients and workplaces: the contribution of the industrial and environmental hygienist

The micropollutants are substances present in the environment in very low concentrations, however, able to alter the balance of the ecosystem or to produce toxic effects, nuisance/odor or “no comfort”. The application of air quality guidelines and limits for occupational exposure in the workplace are the main tools for risk reduction and prevention of the effects of pollutants and micropollutants on health of the general population and workers respectively. The Biological Reference Values (BRVs), determined in situations of non-occupational exposure, and the Biological Limit Values (BLVs) contribute to the interpretation of biological monitoring data. In the occupational field the comparison with the BRVs should be informative about the existence of exposures greater than the general population and are particularly important for substances without VLBs or whose effects include chronic diseases. The investigation strategies are different depending on the objectives and exposure scenarios, in function of the substances and the environment under consideration. The type of limit value defines the mode used for sampling and analysis as well as the mode of comparison with the data (single result or a homogeneous group of exposed). The proper execution of measures and the knowledge of the uncertainty associated with analytical data permit to verify, objectively, the respect of limits, to identify more or less significant deviations and to compare results obtained in different locations or at different times.