Evaluación de la concentración y distribución de metales pesados en el polvo urbano de parqueaderos cerrados y semicerrados de centros comerciales y municipales del Distrito Metropolitano de Quito

Abstract

Heavy metal contamination in urban dust represents a significant environmental problem in areas with high vehicle traffic due to its potential impact on human health and the environment. In this context, the present study evaluated the concentration and distribution of heavy metals in urban dust collected in closed and semi-closed parking lots of shopping centers and municipal buildings in the Metropolitan District of Quito, in order to analyze its potential as an indicator of environmental pollution. The study was conducted using a descriptive-comparative design. A total of 36 urban dust samples were collected in three areas of the city (center, north, and south), considering closed and semi-closed parking lots. Lead (Pb) concentrations were analyzed, as well as the physicochemical properties of urban dust, specifically hydrogen potential (pH) and electrical conductivity (EC), using standardized laboratory techniques and comparative statistical analyses. The results indicated that Pb concentrations remained within the limits established by current environmental regulations, with no statistically significant differences between areas or between types of parking lot, reflecting a homogeneous spatial distribution at the scale of the study. The pH of urban dust was neutral to slightly alkaline and showed similar behavior among the sites evaluated, while electrical conductivity showed variability among the urban areas analyzed, associated with local differences in the accumulation of soluble salts. In general terms, the results showed a low level of lead contamination in the parking lots evaluated. However, a limitation of the study was the spatial scale and the number of sites sampled, so it is recommended that future research be expanded to strengthen the representativeness of the results.