Nano-metal oxides: Exposure and engineering control assessment

Abstract

This paper discusses the evaluation of a facility that produces high quality engineered nanomaterials. These ENMs consist of various metals including iron, nickel, silver, manganese, and palladium. Although occupational exposure levels are not available for these metals, studies have indicated that it may be prudent to keep exposures to the nano-scale metal as low as possible. Previous In vitro studies indicated that in comparison with a material’s larger (parent) counterpart, nanomaterials can move easily through cell membranes and can cause severe toxic effects on human health. The in vitro studies showed that the toxicological effects specific to exposure to nanoscale nickel oxide and nickel have been found to be more inflammatory and toxic than larger-sized nickel particles and can decrease cell metabolic activity, arrest the G2-M cell cycle, and increase cell death. An in vitro study on exposure to iron nanoparticles indicated that the reactive oxygen species produced by exposure may increase cell permeability thereby increasing the potential for vascular movement. Much of the data available on palladium focus on dermal or ingestion exposure; the chronic effects are not well understood. Given the available limited data on the metals evaluated, caution is warranted. One should always keep in mind that the current OELs were not developed specifically for nanoscale particles. With limited data suggesting that certain nanoparticles may be more toxic than the larger counterparts of the same material; employers should attempt to control emissions of these particles at the source, to limit the potential for exposure. Evidence suggests that in general some nanomaterials can be more toxic than their macro-scale counterparts, and therefore caution is warranted. It appears that the personal protective equipment utilized by the employee was appropriate for this type of operation. It should be noted that the use of respiratory protection should not be used as sole protection for any worker, but providing a fit-tested respirator will serve to further decrease the potential for exposure. Instead, it is recommended to control the dispersion of product at the source using local exhaust ventilation, ventilated containment, or fume hoods. Data obtained from the direct reading instruments suggest that reactor cleanout increased the overall particle concentration in the immediate area. However, it does not appear that these concentrations affect areas outside of the production floor. As the distance between the reactor and the sample location increased, the observed particle number concentrations decreased, creating a concentration gradient with respect to the reactor.

Exposure to airborne gold nanoparticles: a review of current toxicological data on the respiratory tract

“…Due to the growing number of workers exposed to NPs, measurement strategies, techniques and methods to evaluate exposure in workplaces have been developed (Brenner et al 2016;Garcia et al 2017;Asbach et al 2017).…”

Refinement of the Nanoparticle Emission Assessment Technique into the Nanomaterial Exposure Assessment Technique (NEAT 2.0)

“…Visualization of air movement patterns is performed using a smoke stick or a smoke generating device. (32) Smoke testing is conducted at the end of the sampling period to avoid inadvertent contamination of samples.…”

More serious autophagy can be induced by ZnO nanoparticles than single‐walled carbon nanotubes in rat tracheal epithelial cells

“…Due to the wide applications of NPs, concerns of the potential risks to human health and the environment posed by NPs have been raised 5 . Garcia found that nanometal oxides can be detected in the personal breathing area of employees in chemical plants 6 . Besides occupational exposure of humans to nanomaterials (NMs), unintentional releases of NMs will be harmful to human and environmental 7 .…”

“…5 Garcia found that nanometal oxides can be detected in the personal breathing area of employees in chemical plants. 6 Besides occupational exposure of humans to nanomaterials (NMs), unintentional releases of NMs will be harmful to human and environmental. 7 Human skin, lungs, and the gastrointestinal tract are in constant contact with the environment, and the lungs and gastrointestinal tract are more vulnerable.…”