Potentially Toxic Elements in Urban Dust of Tlaxcala, Mexico: Pollution Levels and Human and Ecological Risk Assessment

Abstract

The city of Tlaxcala, located in central Mexico, is a small region with high industrial activity that releases potentially toxic elements (PTEs) into the environment. This study investigated the concentration, distribution, contamination levels, and human and ecological health risks of 14 PTEs in 100 urban dust samples collected between February and March 2025. The PTEs were analyzed using inductively coupled plasma optical emission spectrometry. The level of contamination was established using the contamination factor, enrichment, geoaccumulation index, and modified degree of contamination. We assessed human health risks based on non-carcinogenic and carcinogenic risks, as well as potential ecological risks associated with EPT exposure. The results revealed the presence of fourteen EPTs that exhibited the following pattern: Ti > Fe > Mn > Zn > Sb > Sr > Cr > V > Pb > Ni > Cu > Cd > As > Co, where Cd, Sb, and Ti showed high contamination (49.9, 292.6, 166.7) and extremely high enrichment (166.9, 1253, 471.9). The modified degree of contamination indicated contamination in more than 90% of the samples. The health risk index indicated a non-carcinogenic risk to children due to Sb exposure (HI = 2.9). The potential ecological risk was extremely high, with Sb, Cd, and Ti accounting for 99% of the total ecological risk. Although Tlaxcala is a small city, this study revealed high levels of Cd, Sb, and Ti contamination, as well as ecological and health risks to children due to Sb. This may be partly attributed to industrial activity and wastewater discharge from nearby cities such as Mexico City, Puebla, and the State of Mexico. Therefore, environmental and government authorities should consider these findings and reduce pollution levels accordingly.