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

doi:10.1016/j.scitotenv.2019.136481

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

Sci Total Environ. 2020 Apr 15:713:136481. doi: 10.1016/j.scitotenv.2019.136481. Epub 2020 Jan 7.

Authors

Diana Meza-Figueroa¹, Marcelino Barboza-Flores², Francisco M Romero³, Mónica Acosta-Elias², Ernesto Hernández-Mendiola³, Francisco Maldonado-Escalante², Efrén Pérez-Segura¹, Belem González-Grijalva¹, Mercedes Meza-Montenegro⁴, Leticia García-Rico⁵, Sofía Navarro-Espinoza⁶, Karla Santacruz-Gómez⁷, Ana Gallego-Hernández², Martín Pedroza-Montero⁸

Affiliations

¹ Department of Geology, University of Sonora, Rosales y Encinas, Hermosillo, Sonora 83000, Mexico.
² Department of Physics Research, University of Sonora, Rosales y Encinas, Hermosillo, Sonora 83000, Mexico.
³ Institute of Geology, National University of Mexico, Ciudad Universitaria, Delegación Coyoacán, Ciudad de México 04510, Mexico.
⁴ Natural Resources Department, Technological Institute of Sonora, Cd. Obregón, Sonora, Mexico.
⁵ Center of Research in Food and Development, A.C. Carretera a la Victoria km 0.6, Hermosillo, Sonora 83304, Mexico.
⁶ Nanotechnology PhD Program, University of Sonora, Rosales y Encinas, Hermosillo, Sonora 83000, Mexico.
⁷ Physics Department, University of Sonora, Rosales y Encinas, Hermosillo, Sonora 83000, Mexico.
⁸ Department of Physics Research, University of Sonora, Rosales y Encinas, Hermosillo, Sonora 83000, Mexico. Electronic address: martin.pedroza@unison.mx.

PMID: 31954252
DOI: 10.1016/j.scitotenv.2019.136481

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.

Keywords: Agglomerates; Lung bioaccessibility; Metal(oids); Particle size; Playground dust.

MeSH terms

Cities
Dust*
Lysosomes
Metals
Particle Size

Substances

Dust
Metals