Methodological foundations for substantiating safe levels of exposure to artificial nanomaterials (for example, carbon nanotubes) (literature review)

Abstract

Introduction. The unique physicochemical properties of carbon nanotubes allow them to be used in many fields. The global nanomaterials market is growing every year. An important step in introducing products to the domestic and world markets is to determine the safe exposure levels of CNTs. Establishing a corporate standard can serve as a preliminary stage before the approval of a state hygiene standard. Material and methods. The material for the analysis was the sources of information on the available standards for the content of CNTs in the air of the working area using information from regulatory agencies, research centers, CNT manufacturers, bibliographic and abstract databases Web of Science, Scopus, PubMed, RSCI. Results. A scheme for justifying safe levels of exposure to CNTs (corporate standard) has been developed, consisting of several stages: characterization of CNTs in the air at workplaces, selection of experimental doses of CNTs, preparation of CNT dispersions, and conducting toxicological and hygienic experiments. Justification of the corporate standard is carried out in in vitro and in vivo experiments. The planning of experiments should be carried out taking into account the target organ under the influence of CNT - the respiratory system. The recommended dose / concentration range for experiments should include doses / concentrations derived from calculated and literature data. A necessary step is to obtain homogeneous dispersions in which CNTs become bioavailable for biological systems. In vitro and in vivo experiments determine the level of exposure at which no harmful effect is observed and / or the lowest level of exposure at which there is a harmful effect on the cell culture / respiratory tract of animals. After the stage of substantiating the corporate standard, the enterprise should take measures for several years to adjust the corporate standard based on data from clinical and hygienic studies, during which the working conditions and health status of workers are monitored, and extended toxicological and hygienic studies. Conclusion. The presence of a corporate standard will allow the manufacturer of CNTs to carry out activities for the development and implementation of a production control program with the introduction of monitoring the air condition in the working area. The development of a corporate regulation can be seen as a preparatory stage before the establishment of a government regulation.