This project was undertaken to develop a toxicological database allowing the identification of possible additive or other interactive effects of mixtures present in the work environment. In the first phase of the project, whose findings have already been published, critical toxicological data were compiled for each of the 695 chemical substances in the Quebec Occupational Health Regulation, allowing the prediction of potential additivity among components of a mixture. In the second phase of this project, the types of interactions for mixtures most likely to be found in workplaces and for which primary literature data are available were specified. The toxicological data were evaluated only for realistic exposure concentrations up to the short-term exposure limit or ceiling value or five times the 8-hr time-weighted average (TWA) permissible exposure limit (PEL) for human data and up to 100 times the 8-hr TWA PEL or ceiling value for animal studies. In total, 675 studies were evaluated covering 209 binary mixtures of substances. For the majority of cases where potential additivity was identified in Phase 1, there is a lack of toxicological data in the primary literature. In these cases, the results of the first phase will be useful as the default hypothesis. The resulting database integrates the results from both phases of the project. A web-based computer tool allows the user to determine whether there is potential additivity or interaction among components of a mixture.
The online script concordance test developed for this study was found to be both reliable and capable of discriminating between second- and fourth-year optometric students. These results demonstrate that the script concordance test may be considered as a new tool in the optometric educators' assessment arsenal. Further studies will be needed to cover additional levels of professional development.
The increasing number of women in the workplace has made it more important than ever to ensure a safe work environment, particularly with respect to mothers who choose to breast-feed their babies. The Quebec Commission de la santé et de la sécurité du travail (CSST) Toxicological Index is fully involved in the provincial program for the protective reassignment of workers who breast-feed infants. The Infotox database provides peer-reviewed information concerning chemicals identified in the workplace that may appear in the mother's milk, possibly to be ingested by the breast-fed infant. Data extracted from the CSST computer system that holds information on 5,500 substances are presented. A total of 153 chemicals (2.7%) are recognized as being involved in some milk transfer. The strength of evidence is assessed with reference to strong or weak association (excretion or detection) in humans or in animals. Such an effect provides a useful basis for administrative decision involving protective reassignment as well as evaluation of work environment. Database users must be well informed about the identification of chemicals in breast milk because this is an essential step for the evaluation of the hazards of transferring chemicals encountered in the workplace from mother to baby. Actually, the main problem is that there are very few data in the scientific literature concerning milk transfer.
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