Workers’ Exposure to Nano-Objects with Different Dimensionalities in R&D Laboratories: Measurement Strategy and Field Studies

Abstract

With the increasing interest in the potential benefits of nanotechnologies, concern is still growing that they may present emerging risks for workers. Various strategies have been developed to assess the exposure to nano-objects and their agglomerates and aggregates (NOAA) in the workplace, integrating different aerosol measurement instruments and taking into account multiple parameters that may influence NOAA toxicity. The present study proposes a multi-metric approach for measuring and sampling NOAA in the workplace, applied to three case studies in laboratories each dedicated to materials with different shapes and dimensionalities: graphene, nanowires, and nanoparticles. The study is part of a larger project with the aim of improving risk management tools in nanomaterials research laboratories. The harmonized methodology proposed by the Organization for Economic Cooperation and Development (OECD) has been applied, including information gathering about materials and processes, measurements with easy-to-use and hand-held real-time devices, air sampling with personal samplers, and off-line analysis using scanning electron microscopy. Significant values beyond which an emission can be attributed to the NOAA production process were identified by comparison of the particle number concentration (PNC) time series and the corresponding background levels in the three laboratories. We explored the relations between background PNC and microclimatic parameters. Morphological and elemental analysis of sampled filters was done to identify possible emission sources of NOAA during the production processes: rare particles, spherical, with average diameter similar to the produced NOAA were identified in the nanoparticles laboratory, so further investigation is recommended to confirm the potential for worker exposure. In conclusion, the information obtained should provide a valuable basis for improving risk management strategies in the laboratory at work.

Emissions and exposures of graphene nanomaterials, titanium dioxide nanofibers, and nanoparticles during down-stream industrial handling

“…EC analysis is much less labor intensive than the SEM/TEM method. In previous workplace studies of graphene, Lee et al [18] and Vaquero et al [21] also used EC as an exposure metric for graphene, while exposure data of EC are missing in the studies by Spinazze et al [19] and Boccuni et al [20]. In the current study, EC concentrations collected as total dust fractions were detected both in emission zone and personal breathing zone filter samples, for example during weighing and mixing of graphene oxide.…”

“…This was further pointed out by Arvidsson et al [13], who requested that workplace emissions and exposures of graphene should be investigated. Only a few emission and exposure measurements during production [18][19][20][21] and handling [18] of graphene nanomaterials have since then been conducted. These studies showed low levels of exposures to graphene.…”

Occupational exposure to graphene based nanomaterials: risk assessment

“…38 Comparable results were recently recorded for graphene within a study proposing a multi-metric approach based on the harmonized and tiered OECD methodology, in a research and development laboratory. 39 All these concentrations are far lower than the inhalation exposure levels to GBMs provoking toxicity in animals, as assessed by inhalation studies (see above).…”

Nanoparticles: An Experimental Study of Zinc Nanoparticles Toxicity on Marine Crustaceans. General Overview on the Health Implications in Humans

“…In fact, competent authorities applying the principle of "no data, no market" (12) could prevent the use and sale of materials that are presumed to be dangerous for which there is no toxicological and ecological information. (24,36,39,40). All these aforementioned NPs properties are important when we study the human health risk i.e., exposure (deposition and agglomeration), absorption and distribution (transport across biological barriers such as the gut epithelium, blood-brain barrier, or skin), accumulation, and toxic potency (dose-response relationships) (41).…”

“…For many NPs, to date, data on doseresponse, exposure assessment and risk characterization, are insufficient to define risk management (1,6,7,11,49,75). In a recent systematic review, only 56 occupational exposure limits (OELs) developed for engineered NMs have been reported (36,75). As previous referred due to the interaction of NPs with environment or biologic fluids consumers, workers and environment are exposed to transformed NMs, that may have acquired different toxicity profiles (11,79).…”