A standardized non-instrumental method for tracking workstations concerned with exposure to nano-objects and their aggregates and agglomerates in companies dealing with engineering nanomaterials
Résumé
The French national epidemiological surveillance program EpiNano aims at surveying mid- and long-term health effects possibly related with occupational exposure to either carbon nanotubes (NTC) or titanium dioxide nanoparticles (TiO2). EpiNano is limited to workers potentially exposed to these nanomaterials (NM) including their aggregates and agglomerates. In order to identify those workers during the in-field industrial hygiene (IH) visits, a standardized non-instrumental method is necessary especially for epidemiologists and occupational physicians unfamiliar with ENM exposure metrology. A working group, Quintet ExpoNano, including national experts in NM metrology and occupational hygiene reviewed available methods, resources and their practice in order to develop a standardized tool for conducting company IH visits and collecting necessary information. This tool, entitled “Field technical logbook”, includes 3 parts: company activity, workplace, and workstation allowing a detailed description of each task, process and exposure surrounding conditions. This logbook is intended to be completed during the company IH visit. Each visit is conducted jointly by an occupational hygienist and an epidemiologist of the program and lasts one or two days depending on the company size. When all collected information is computerized in a friendly-using database it is easy to classify workstations with respect to their potential direct and/or indirect exposure. Workers appointed to workstations classified as concerned with exposure are considered as eligible for EpiNano program and invited to participate. Since January 2014, the Field technical logbook has been used in ten company visits. The companies visited were mostly involved in research and development. A total of 53 workstations with potential exposure were pre-selected and observed: 5 with TiO2, 16 with single-walled NTC, 27 multiwalled NTC. Among the tasks observed there were: ENM analysis (8), weighing (7), synthesis (6), functionalization (5), and transfer (5). The manipulated quantities were usually very small. After analysis of the data gathered in logbooks, 30 workstations have been classified as concerned with exposure to NTC or TiO2. Additional tool validity as well as inter-and intra-evaluator reproducibility studies are ongoing. These first results are promising.