Heavy Metal Contamination (Cu, Pb, Zn, Fe, and Mn) in Urban Dust and its Possible Ecological and Human Health Risk in Mexican Cities

Anahi Aguilera,Avto Goguitchaichvili,José Luis Cortés,Francisco Bautista,Patricia Quintana,Yameli Aguilar,Carmen Delgado,Daniel Aguilar,Ruben Cejudo

doi:10.3389/fenvs.2022.854460

Abstract

Cities occupy a relatively small percentage of the Earth’s surface. However, they influence the entire biosphere, affect biodiversity and environmental conditions, which end up affecting human health and well-being. Therefore, it is necessary to evaluate the level of contamination by heavy metals in urban environments, as well as the possible ecological and human health risks. In this study, the urban dust of six Mexican cities was analyzed and it was found that all studied cities were contaminated, except for Mérida, when soil world background value was used as reference. In contrast, Mérida and Morelia were the most contaminated when a local background was used (decile 1). The concentrations in the cities for the metals Cu, Pb and Zn, decreased in the order CDMX &gt; San Luis Potosí &gt; Toluca &gt; Morelia-Ensenada &gt; Mérida. In the particular case of Cu and Pb, SLP accompanied CDMX as the most polluted city. For Mn and Fe concentrations, the order was CDMX &gt; Toluca &gt; Ensenada &gt; SLP &gt; Morelia-Mérida. No potential ecological risk was found due to contamination by Cu, Pb, and Zn, in the urban dust of the studied cities. However, the higher metal contribution to the potential ecological risk in all the cities was from Pb; and it represented a moderate ecological risk of more than 25% on CDMX, SLP, and Toluca sites. Pb can also be a potential risk for children’s health. In addition, chronic exposure to Fe and Mn could trigger many ailments. In the future, it is important to identify the main sources of Pb in cities and seek mitigation strategies to reduce the possible adverse effects that this metal may be causing.

Highlights

Cities occupy a small percentage of the global land surface (~5%) but can influence the entire biosphere (Angeoletto et al, 2015)
Urban dust is made up of solid particles deposited on impermeable materials that originate from the interaction of solids, liquids, and gases in the environment (Keshavarzi et al, 2018)
Cu and Zn were strongly correlated (r = 0.82), and they had a weaker correlation with Pb (Pb-Cu, r = 0.5; Pb-Zn, r = 0.35). This seems to indicate that Fe and Mn are elements that can share similar sources; they have been reported as elements of natural or mixed origin (Dehghani et al, 2016), in studies of heavy metals

Summary

Introduction

Cities occupy a small percentage of the global land surface (~5%) but can influence the entire biosphere (Angeoletto et al, 2015). Urban dust is made up of solid particles deposited on impermeable materials that originate from the interaction of solids, liquids, and gases in the environment (Keshavarzi et al, 2018). Urban dust is a receptor for solid particles from different sources, it becomes a sink for atmospheric particles. Urban dust can be considered as a pollutant source into the atmosphere and soils, through the re-suspension of this material. It can be a source of contaminants for water (Keshavarzi et al, 2018; Safiur Rahman et al, 2019), through rain runoff (Jayarathne et al, 2018)

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Results

Conclusion