The study of metal contamination in urban topsoils of Mexico City using GIS

Abstract

This research presents and discusses information concerning the spatial distribution of heavy metals (Pb, Cu, Zn, Ba, Co, Cr, Ni and V) in the urban environments of Mexico City using geographical information system and statistical analysis. Superficial soil samples (n = 146) were analyzed. The highest contamination indices were found in the north and center zone of the metropolitan area. In contrast, the surrounding rural fields show a lower impact grade. The higher concentrations of Pb, Cu, Zn and Ba were observed as being related to high vehicular traffic, nevertheless other elements such as Co, Cr, Ni and V do not show anthropogenic influence and their content can be attributed to the parental rock. The results are compared with previous surveys carried out in 2003 in order to evaluate temporal deposition trends. No changes were found on reported concentrations except for Cu and Zn, whose concentration has increased in later years. The results suggest that spatial distribution analysis and results in comparison with previous studies could be useful for the management and sustainable development of the metropolitan area of Mexico City.

Distribución espacial de los metales pesados en polvos urbanos de la ciudad de Ensenada, Baja California, México

“…Un plan de saneamiento debe instrumentarse para esos lugares, ya que el V es un elemento que si se inhala o ingiere vía oral o por contacto vía dermis, es causal de cáncer, afecta la reproducción y es bioacumulativo (Méndez, Báez, & Patricia, 2014;Rodríguez-Mercado & Altamirano-Lozano, 2006). …”

“…A sanitation plan should be implemented for these places, since V is an element that if it is inhaled or ingested orally or direct person-to-person via the dermis, causes cancer, affects reproduction and is bioaccumulative (Méndez, Báez, & Patricia, 2014;Rodríguez-Mercado & Altamirano-Lozano, 2006).…”

Dust–Metal Sources in an Urbanized Arid Zone: Implications for Health-Risk Assessments

“…These differences may be related to the city size and industrial activities; however, similar metal contents have been reported in top soils in Mexico City (Rodríguez-Salazar et al 2011), which is the largest city in the country.…”

“…In the case of Pb, only two samples of road dust yielded values above the recommended limit (400 mg kg -1 ); both samples correspond to high-traffic areas. According to Del Rio-Salas et al (2012) and Rodríguez-Salazar et al (2011), Pb isotopic ratios suggest pollution by Pb in gasoline. In Mexico, using Pb as a gasoline additive has been prohibited since 1987; however, a recent study suggests a mixing of Pb isotopic signatures from leaded gasoline and urban dust.…”

“…Geographic Information System (GIS)-based maps are useful to show the spatial distribution of pollutants, socioeconomic conditions, vulnerability (marginality index), and number of people at risk for excessive intake. Published studies on mapping human health risk are related to exposure to metals in soil, water, and food (Rodríguez-Salazar et al 2011;Dao et al 2013); however, to our knowledge, no studies have been published on mapping human health risks related to resuspended dust in urban environments including settled dust on roofs.…”