CONICET | Buscador de Institutos y Recursos Humanos

Passive natural collectors of contaminants have become important for monitoring urban and industrial pollution; in this contribution, the species Tillandsia recurvata L. was studied, specially, using magnetic measurements. This plant is able to absorb water, dusts and nutrients directly from the air; for this reason and because of its availability, the species was selected as a monitor of air pollution in the metropolitan area of Santiago de Querétaro, Mexico. Individuals were collected in sites that are subjected to different pollution degrees and sources. Elements of interest were detected (including: Fe, O, Si, As, Sb, S, Cr, Mo, V, Zn, Ba, Pt, Cu) by ICP and particle morphologies by SEM-EDS analysis. Magnetic measurements include: hysteresis cycles, magnetic susceptibility (X), anhysteretic and isothermal remanent magnetization (ARM and IRM) and thermomagnetic studies. In industrial and heavy traffic sites, the highest values of magnetic concentration dependent parameters were observed (e.g.: X ~ 186 x10-8 m3 kg-1, ARM ~ 387 x10-6 A m2 kg-1 and SIRM ~ 32 x10-3 A m2 kg-1), in contrast, sites with low vehicular traffic reached low values (e.g.: X ~ 1.1 x10-8 m3 kg-1, ARM ~ 11.1 x10-6 A m2 kg-1 and SIRM ~ 0.5 x10-3 A m2 kg-1). Furthermore, the integrated magnetic analysis (King´s and Day´s plots, remanent parameters and thermomagnetic measurements) revealed the presence of ferromagnetic minerals, magnetite-like with fine grain sizes (0.1-5 microns). In order to analyze the pool of data, descriptive statistics like population indicators (mean, variance, etc) and correlation Pearson index were calculated. The relationship between magnetic and chemical variables was analyzed using fuzzy c-means clustering analysis. These results demonstrate the usefulness of the species Tillandsia recurvata L. as a passive pollution monitor, with an affordable and immediate application.

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