In vitro assessment oral and respiratory bioaccessibility of Mn in school dust: Insight of seasonality in a semiarid environment

Benedetto Schiavo*, Diana Meza-Figueroa*, Martín Pedroza-Montero, Jesús Vidal-Solano, Belem González-Grijalva, Sofía Navarro-Espinoza, Francisco Romero, Ernesto Hernández, Margarita E. Gutiérrez-Ruiz, Agueda E. Ceniceros-Gómez

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


In school environments in the Sonoran Desert, dust contains anomalously high manganese (Mn) of geogenic origin, similar to those reported at industrial sites. Non-carcinogenic risk assessment for children exposed to Mn was estimated for two sampling seasons (pre-monsoon, post-monsoon). We determined the total Mn content in school dust samples by portable X-ray fluorescence (PXRF), and we used geochemical indices for Mn-source apportionment. We identified dust mineralogy by X-ray diffraction (XRD). We obtained the oral and lung bioaccessibility by in vitro tests. The results showed a much higher total Mn content (1725.7 mg·kg−1) in the <20 μm school dust size fraction in the pre-monsoon season compared to the average value post-monsoon (582.9 mg·kg−1). Moreover, in pre-monsoon season, the estimated hazard quotient (HQ) and hazard index (HI) for Mn were higher than 1, representing a potential health risk. Mn's oral and lung bioaccessibility also differed significantly between the sampling seasons, but the behavior was opposite to total Mn-content. The maximum gastric/intestinal bioaccessibility for Mn ranged from 10.6/1.7 pre-monsoon to 28.5/9.0% post-monsoon. In the simulated lung fluid, the maximum bioaccessibility of Mn ranged from 15.6% pre-monsoon to 64.1% post-monsoon. This variability was probably due to differences in Mn mineralogy (todorokite in pre-monsoon dust; an unknown phase in post-monsoon dust). Our results show that it is necessary to integrate seasonal sampling into risk assessment in arid zones worldwide, where dust resuspension processes commonly occur.

Original languageEnglish
Article number105102
JournalApplied Geochemistry
StatePublished - Nov 2021

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© 2021 Elsevier Ltd


  • Arid environment
  • Bioaccessibility
  • Health risk
  • Manganese
  • School dust


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