Cecilia Van Cauwenberghe from Frost & Sullivan’s TechVision Group assesses nanomaterials health risks in the workplace, starting with an overall perspective on the topic that includes risk assessment policies
Nanomaterials can be grouped following the directives of the European Center for Ecotoxicology and Toxicology of Chemicals (ECETOC) Task Force on Nanomaterials. Such a comprehensive concept for the grouping and testing of nanomaterials was denominated as DF4nanoGrouping (Gupta et al., 2018). This assessment framework assigns nanomaterials to four main groups (MG) as follows: soluble nanomaterials (MG1), biopersistent high aspect ratio nanomaterials (MG2), passive nanomaterials (MG3) and active nanomaterials (MG4) (Liu et al., 2019). Concomitantly, in order to make this characterisation consistent, DF4nanoGrouping considers material properties as follows: intrinsic properties in Tier 1, comprising water solubility, particle morphology and chemical composition; system-dependent properties in Tier 2, including dissolution in biological media, surface reactivity, particle dispersibility and in vitro effects; testing properties, in Tier 3, comprehending non-animal testing confirmed or corrected using data from short-term in vivo studies (Bianchi et al., 2019).
Exposure in the workplace
Engineered nanoparticles can be exogenously ingested from hand-to-mouth contact at the workplace. Whereas larger particles of 5–30 μm are usually placed in the nasopharyngeal region, smaller particles of 1–5 μm are dropped in the tracheobronchial region. Once ingested or inhaled, particles may be further absorbed or removed by mucociliary clearance. If absorbed, nanoparticles can penetrate and travel into the gastrointestinal (GI) tract. Submicron particles of less than 1 μm and nanoparticles of 100 nm can penetrate into the alveolar region, from where they cannot be removed.
Moreover, once in close contact with the alveolar epithelium soluble nanoparticles can penetrate other tissues and trigger particle–cell interactions, cross the blood–air–tissue barrier and enter the bloodstream, thereby potentially reaching other target organs. On the other hand, insoluble nanoparticles may prolong their residence in the lung leading to injury and immune responses, as well as serving as cleavage for tumour cells (Keller and Parker., 2019). Therefore, typical exposure to nanomaterials at the workplace is deeply related to a broad spectrum of both acute and chronic effects, including inflammation, asthma, cystic fibrosis, lung diseases and cancer. Neurotoxicity represents another health risk. Inhaled nanoparticles inside the olfactory mucosa may translocate in the central nervous system (CNS).
Final disposal considerations
The generation of nanomaterial waste is difficult to assess. Both effective dilution and proven deactivation are crucial for clean and safe nanomaterials disposal. The three pathways followed for nanomaterials waste disposal are: landfill, thermal treatment and recycling, all of which are strictly dependent on the material type and the overall conditions of the nanomaterials waste. It is important to highlight that material recovery or recycling may involve some lateral risks, such as occupational health effects of recycling processes, the environmental impact associated with the final disposal of the residues and the introduction of residual nanomaterials into recycled products (Resnik, 2019).
Nanomaterials present various severe health risks for people handling them. The effective and safe management of health hazards associated with the manipulation of engineered nanoparticles must consider the nanomaterial route from manufacturing and distribution to storage and final disposal. Europe is advancing toward the institution of effective policies that strive for a more cautious manipulation of engineered nanomaterials at the stages of manufacturing, use and recycling.
I would like to thank all contributors from the industry involved with the development and delivery of this article from the TechVision Group at Frost & Sullivan.
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Gupta, R. and Xie, H., 2018. Nanoparticles in daily life: applications, toxicity and regulations. Journal of Environmental Pathology, Toxicology and Oncology, 37(3)
Keller, A.A. and Parker, N., 2019. Innovation in procedures for human and ecological health risk assessment of engineered nanomaterials. In Exposure to Engineered Nanomaterials in the Environment (pp. 185- 208). Elsevier.
Liu, Y., Jiang, H., Liu, C., Ge, Y., Wang, L., Zhang, B., He, H. and Liu, S., 2019. Influence of functional groups on toxicity of carbon nanomaterials. Atmospheric Chemistry and Physics, 19(12), pp.8175-8187.
Resnik, D.B., 2019. How Should Engineered Nanomaterials Be Regulated for Public and Environmental Health? AMA journal of ethics, 21(4), pp.363-369.