Metal bioaccessibility, particle size distribution and polydispersity of playground dust in synthetic lysosomal fluids

Diana Meza-Figueroa, Marcelino Barboza-Flores, Francisco M. Romero, Mónica Acosta-Elias, Ernesto Hernández-Mendiola, Francisco Maldonado-Escalante, Efrén Pérez-Segura, Belem González-Grijalva, Mercedes Meza-Montenegro, Leticia García-Rico, Sofía Navarro-Espinoza, Karla Santacruz-Gómez, Ana Gallego-Hernández, Martín Pedroza-Montero*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Inhalation of playground dust-derived fine particles in schoolyards poses a risk from exposure to metal(oids) and minerals. In this work, we obtained the total concentration and bioaccessibility of metal(oids) with Gamble Solution (GS) and Artificial Lysosomal Fluid (ALF) synthetic solutions, simulating the extracellular neutral pH environment of the lung and the intracellular conditions of the macrophage, respectively. Scanning Electron Microscope (SEM), and Dynamic Light Scattering analysis (DLS) techniques were used to characterize particles with a size smaller than 2.5 μm, which can be assimilated by macrophages in the deep part of the lung. Arsenic (As), lead (Pb), copper (Cu), manganese (Mn), zinc (Zn), and iron (Fe) showed concentrations of 39.9, 147.9, 286, 1369, 2313, 112,457 mg·kg 1, respectively. The results indicated that all studied elements were enriched when compared to (i) local geochemical background and (ii) findings reported in other cities around the world. Bioaccessibility of metal(oids) in GS was low-moderate for most studied elements. However, in ALF assays, bioaccessibility was high among the samples: for lead (Pb = 34–100%), arsenic (As = 14.7–100%), copper (Cu = 17.9–100%), and zinc (Zn = 35–52%) possibly related to hydrophobic minerals in dust. SEM and DLS image analysis showed that playground dust particles smaller than 2.5 μm are dominant, particularly particles with a size range of 500–600 nm. The polydispersity detected in these particle sizes showed that most of them might be crystalline compounds (elongated shapes) forming agglomerates instead of combustion particles (spheres). Moreover, the circularity detected varies from 0.57 to 0.79 (low roundness), which corroborates this finding. The presence of agglomerates of ultrafine/nanoparticles containing highly bioaccessible metals in playground sites may have severe implications in children's health. Therefore, further studies are required to characterize the size distribution, structure, shape and composition of such minerals which are essential factors related to the toxicology of inhaled dust particles.

Original languageEnglish
Article number136481
JournalScience of the Total Environment
Volume713
DOIs
StatePublished - 15 Apr 2020
Externally publishedYes

Bibliographical note

Funding Information:
The authors acknowledge the financial support provided by the National Council of Science and Technology (Consejo Nacional de Ciencia y Tecnología, CONACYT) via the grant A1-S-29697 (Prof. Diana Meza-Figueroa) and the grant PDCPN2014-01/248982 (Prof. Martin Pedroza-Montero). The authors also acknowledge the support of a postdoctoral scholarship to Francisco Maldonado-Escalante by the Secretariat of Public Education in Mexico (SEP) and the Repatriation Fellowship of Ana L. Gallego Hernández by CONACYT. Thanks to Dr. Paul W. Kilpatrick for help with the English edition through the support for the ITSON project PROFAPI_2019_0037. Authors acknowledge Roberto Ochoa-Contreras for conducting the XRD analysis.

Funding Information:
The authors acknowledge the financial support provided by the National Council of Science and Technology (Consejo Nacional de Ciencia y Tecnolog?a, CONACYT) via the grant A1-S-29697 (Prof. Diana Meza-Figueroa) and the grant PDCPN2014-01/248982 (Prof. Martin Pedroza-Montero). The authors also acknowledge the support of a postdoctoral scholarship to Francisco Maldonado-Escalante by the Secretariat of Public Education in Mexico (SEP) and the Repatriation Fellowship of Ana L. Gallego Hern?ndez by CONACYT. Thanks to Dr. Paul W. Kilpatrick for help with the English edition through the support for the ITSON project PROFAPI_2019_0037. Authors acknowledge Roberto Ochoa-Contreras for conducting the XRD analysis.

Publisher Copyright:
© 2020 Elsevier B.V.

Keywords

  • Agglomerates
  • Lung bioaccessibility
  • Metal(oids)
  • Particle size
  • Playground dust

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