Abstract

CEJUDO, Rubén; BAUTISTA, Francisco; GOGUITCHAICHVILI, Avto  and  CERVANTES-SOLANO, Miguel A.. Magnetic parameters and concentration of heavy metals in urban dust of Mexico City. Bol. Soc. Geol. Mex [online]. 2022, vol.74, n.1, e060821.  Epub May 02, 2023. ISSN 1405-3322.  https://doi.org/10.18268/bsgm2022v74n1a060821.

A combined magnetic and geochemical analysis was carried out to identify the relationship between magnetic parameters, concentration of major elements and heavy metals in urban dust of Mexico City. Here, we propose simple mathematical models that can estimate the concentration of elements in urban dust by means of magnetic parameters, as well as establish the degree of precision of each model. Magnetic threshold values are also proposed to identify samples with low, medium and high concentrations of elements. Urban dust from Mexico City showed a different concentration of essentially ferrimagnetic minerals and superparamagnetic particles. The concentration of the elements in the urban dust samples were: Al between 3,325 to 27,336 mg kg-1; Cr between 17 to 117 mg kg-1; Cu between 15 to 405 mg kg-1; Fe between 653 to 39,217 mg kg-1; Ni between 21 to 66 mg kg- 1; Pb between 27 to 366 mg kg-1; V between 11 to 52 mg kg-1 and Zn between 102 to 537 mg kg-1. The relationship between magnetic parameters and concentration of element is rather linear, showing positive Pearson correlation coefficients with values between 0.26 to 0.69. Magnetic threshold values were proposed to identify sites with relatively high accumulation of Cr, Cu, Ni, Pb and Zn. These values for specific magnetic susceptibility are: Low < 2.86 µm3 kg-1; Moderate: 2.86 to 3.46 µm3 kg-1 and High > 3.46 µm3 kg-1; and for remanent isothermal magnetization of saturation: Low < 38 mAm2 kg-1; Moderate: between 38 to 46 mAm2 kg-1 and High > 46 mAm2 kg-1. Mathematical models to estimate the concentration of elements showed effectiveness of about 60%.

Keywords : Pollution; Mexico City; Magnetic properties; major elements; heavy metals.