Human health no-effect levels of TiO2 nanoparticles as a function of their primary size

Abstract

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Development of Comparative Toxicity Potentials of TiO2 Nanoparticles for Use in Life Cycle Assessment

“…This discrepancy can mainly be explained by the assumption made by Pini et al 35 to use a no-observed adverse effect level (NOAEL) value for ingestion exposure when determining an EF for inhalation. As reported in Laurent et al 66 , NOAELs differ by several orders of magnitude between the two exposure routes, with regression analyses on available toxicological data for TiO 2 showing a factor of ca. 40 between the two.…”

“…To determine ED50 for non-carcinogenic effects of TiO 2 nanoparticles, the study conducted by Laurent et al 66 was used. In this study, a critical review of in vivo studies was performed and relationships between non-observed adverse effect levels (NOAEL) and the primary particle sizes of the particles were investigated.…”

“…40 between the two. 66 Provided that the extrapolations from NOAELs (expressed as daily chronic intake dose)…”

“…This is regarded as unrealistic considering the IARC classification of TiO 2 as possibly carcinogenic to humans 92 , in contrast to substances like arsenic, nickel or beryllium, all of them being classified as carcinogenic to humans and reported in USEtox 2.0. Based on the study by Laurent et al 66 , who used the National Institute of Occupational Safety and Health (NIOSH) exposure thresholds 93 , as did Pini et al 35 , an EF value of 7.4E-2 cases/kg-inhaled should be found when applying the methodology reported by Pini et al 35 With respect to the ingestion pathway, Jovanović 67 showed that although nano-TiO 2 has the potential for absorption and storage in various organs by mammals, no study has demonstrated that ingestion of TiO 2 could induce carcinogenic effects. 67,92 Therefore, the EF value for carcinogenic effects through ingestion was set to 0 cases / kg-ingested (see Table 1).…”

Estimating human exposure to titanium dioxide from personal care products through a social survey approach

“…Research also investigated the inhalation impacts of P25 TiO 2 NPs to wistar rats and 2 different strains of mice at an average concentration of 10 mg/m 3 , where toxic effects were found on alveolar macrophages and alveolar lung particle clearance (Heinrich et al ). In another study, Laurent et al summarized no‐observed‐adverse‐effect level (NOAEL) and lowest‐observed‐adverse‐effect level (LOAEL) values of TiO 2 NPs in various in vivo studies and predicted the LOAEL (NOAEL) concentrations to be 0.0836 to 4.05 (0.0171–10.5) mg/kg bw per day for exposure through the inhalation route (Laurent et al ). Tsang et al () used 2 studies (Heinrich et al ; Bermudez et al ) combining nano‐TiO 2 and fine‐TiO 2 to calculate carcinogenic ED50, and obtained a value of 1.58 μg/g wet lung (1.43 m 2 /g dry lung).…”