IDENTIFICATION OF AREAS CONTAMINATED WITH HEAVY METALS IN THE URBAN DUST OF THE CITY OF MEXICO

Seven million people die per year of cancer related to environmental pollution. Urban dust (UD) contains particles smaller than 10 mu m that affect human health. In Mexico City (CDMX) only one study on UD has been conducted. The objective of this study was to identify the areas most likely to be contaminated by heavy metals (HM) contained in the UD of CDMX. Eighty nine UD samples were collected; the analysis of the HM concentration was made by X-ray fluorescence, and spatial analysis by interpolation with kriging indicator. The percentage of the area with the highest probability that HMs exceeded the maximum permitted limits (MPL) were: Cr (MPL 280 mg/kg), 0.55 %, southwest of the CDMX; Cr (MPL 64 mg/kg), 89 %, all CDMX and most of the conurbated areas (CA); Cu, 17 %, 11 municipalities and the northern CA; Ni, 13 %, center and southwest of the CDMX; Pb (MPL 140 mg/kg), 17.5 %, centric municipalities and the northwest CA; Pb (MPL 400 mg/kg), 2.2 %, centric municipalities and the northwest CA; V, 26 %, centric and southern municipalities and the northeast CA; Zn, 21%, centric municipalities and the northern CA. Elements with a greater number of sites and contaminated surface are: Cr, Zn, Cu and Pb. The largest HM overlapping sites are those with Cu and Zn associations (15 %), and Cu and Pb associations (13 %). The municipalities Cuauhtemoc, Venustiano Carranza and Gustavo A. Madero are the most contaminated with heavy metals.