Short term exposures, proposal of a methodology
Abstract
The development of threshold toxicity values for chemicals for human health is an essential step of health and safety risk assessments. A method based on the use of existing values and/or the development of new values has been developed for short term exposure period (1-14 days) for both oral and inhalation exposures. Some existing toxicological reference values (TRV) developed for those periods of exposure could be used. Guideline values could be an useful alternative when they were determined as TRV. If several values are available, the most appropriate value has to be chosen. This choice is performed by analysis of the quality of the key-study in relation to the period of short term exposure. The parameters for the building of the TRV are evaluated and benchmark approach is preferred than those using No Observed Effect Level (NOAEL) or Low Observed Effect Level (LOAEL). Then, each uncertainty factor is studied in relation to key-study, database and TRV construction. If only one value is available its quality is verified. Finally, in the absence of existing values, a new threshold value may be established by our method. This method is not applicable for carcinogenic effects. The method is an easy tool to use and allowed the selection of values checked qualitatively and considered in line with the most appropriate available scientific data. However, the methodology could be applied for the selection and the establishment of short term threshold values by public health actors.