Inhalation toxicity of 316L stainless steel powder in relation to bioaccessibility

Abstract

The Globally Harmonized System for Classification and Labelling of Chemicals (GHS) considers metallic alloys, such as nickel (Ni)-containing stainless steel (SS), as mixtures of substances, without considering that alloys behave differently compared to their constituent metals. This study presents an approach using metal release, explained by surface compositional data, for the prediction of inhalation toxicity of SS AISI 316L. The release of Ni into synthetic biological fluids is >1000-fold lower from the SS powder than from Ni metal, due to the chromium(III)-rich surface oxide of SS. Thus, it was hypothesized that the inhalation toxicity of SS is significantly lower than what could be predicted based on Ni metal content. A 28-day inhalation study with rats exposed to SS 316L powder (<4 µm, mass median aerodynamic diameter 2.5-3.0 µm) at concentrations up to 1.0 mg/L showed accumulation of metal particles in the lung lobes, but no signs of inflammation, although Ni metal caused lung toxicity in a similar published study at significantly lower concentrations. It was concluded that the bioaccessible (released) fraction, rather than the elemental nominal composition, predicts the toxicity of SS powder. The study provides a basis for an approach for future validation, standardization and risk assessment of metal alloys.

Bioaccessibility of micron-sized powder particles of molybdenum metal, iron metal, molybdenum oxides and ferromolybdenum – Importance of surface oxides

“…This approach has been shown erroneous for alloys such as stainless steels, ferrochromium alloys, and ferrosilicochromium alloys Herting et al, 2005;Hillwalker and Anderson, 2014;Midander et al, 2010;Santonen et al, 2010;Stockmann-Juvala et al, 2013). A main reason is that these alloys all have surface oxides that have different properties compared with surface oxides of their individual metal constituents, and that all alloy components may not be present in the outermost surface oxide but may appear in adjacent alloy surface layers beneath the oxide, or in the bulk alloy.…”

“…This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). composition, and that read-across from pure metals is often highly erroneous Herting et al, 2005;Hillwalker and Anderson, 2014;Stockmann-Juvala et al, 2013).…”

Análisis de la microestructura de humos de soldadura de aceros de bajo y medio contenido de carbon

“…However, previous studies have experimentally showed that metals and heavy metals emitted by welding fumes still pollute the environment. • Therefore, it can be clearly stated that these materials are vented into the atmosphere and threaten the environment and human health because the fume produced during the welding process contains many different oxides and elements (Stockmann-Juvala et al, 2013;Stebounova et al, 2018;McCarrick, et al, 2019). • The data obtained in this study provide important information for understanding the effects of welding fumes on health and environment.…”

Selective Laser Melting of Stainless Steel 316L with Face-Centered-Cubic-Based Lattice Structures to Produce Rib Implants

“…Another challenge that may cause the failure of SS316L implant is the potential possibility for secondary phases or precipitation phases in material to occur during implant fabrication or working conditions [6,7]. The precipitates lead to localized corrosion of the SS316L when subjected to human body fluids and release unused elements that may become toxic inside the human body [8][9][10]. Therefore, efforts to fabricate good austenitic stainless steel that matches the density and stiffness of human ribs are necessary.…”