Identification of early effects induced in case of exceeding toxicological threshold value : A tool for risks manager for communication to exposed populations
Abstract
When exposure levels exceed recommended toxicological threshold value, calculated to protect human from adverse effects, the conclusion of the risk assessment identifies a potential risk for the exposed population. The construction of these threshold values includes a margin of safety in order to cover uncertainties and extrapolations to be sufficiently protective over a lifetime. In practice, encountered situations include cases where, levels are just above recommend values corresponding to low level of exposure and the duration of exposure is usually between few months and 2–3 years. In this context, it could be useful to propose a new analysis of the data to give more effective tools to risk managers in order to communicate information to the population. We propose an analysis of all the data available and more especially those from epidemiologic studies, in the range of duration and level of exposure related, to this kind of events. The analysis is made taking into account the quality of the studies. Two substances are presented as two case-studies: perchloroethylene (tetrachloroethylene) and mercury (inorganic form). In both cases, first results show that changes of the neurologic parameters are the most sensitive effects. They have also underlined the lack of appropriate epidemiologic data and the difficulty to use experimental ones in this case. A schematic representation of all the data could bring an overview of the potential effects of the substance. This representation could be easily analyzed by risk managers and useful for the communication to exposed population.