Database for the toxicological evaluation of mixtures in occupational atmospheres.

Workers are regularly simultaneously exposed to multiple chemical substances. As in the ACGIH (American Conference of Governmental Industrial Hygienists) approach, the Québec Regulation prescribes that when two or more hazardous substances are present in workplaces and have similar effects on the same organs of the human body, their effects should be considered additive, unless established otherwise. This project was undertaken to develop a user-friendly toxicological database aid in identification of possible interactive effects of mixtures present in the work environment. In the first phase of the project, standard general literature references were used to compile critical data, such as target organs, effects on the target organs, mechanisms of action, and toxicokinetic characteristics of each of the 668 chemical substances appearing in the regulation. Each substance was assigned to one or more of 32 classes of biological effects retained by a group of toxicologists. The resulting database allows the user to find if there is potential additivity among components of a mixture.