Comparative study between the bromeliad Tillandsia usneoides and the Tipuana tipu tree barks for use in active biomonitoring of atmospheric pollution

Biomonitoring of atmospheric pollution is a technique which organisms are used to quantify pollutants levels. nowadays, several plant species have been analyzed in order to assess their feasibility for use in biomonitoring of air pollutants. The objective if this research was to compare the bromeliad T. usneoides with T. tipu tree barks for application in the active biomonitoring of atmospheric pollution. These two species of biomonitors have been extensively analyzed, mainly in the state of Sao Paulo, Brazil. The experimental part consisted of the steps: acquisition of samples of samples of both species of biomonitors, preparation of samples for exposure, exposure, collection of exposed samples, treatment of samples for analysis, and analysis by the Instrumental Neutron Activation Analysis (INAA). Analytical quality control was performed by the analyses certified reference materials, which indicated good precision and accuracy with values of |En score| < 1. Results obtained in the biomonitor analyses indicated in both species the elements As, Br, Ca, Cl, Co, Cr, Cs, Fe, K, La, Mg, Mn, Na, Rb, Sb, Sc, V and Zn could be determined. Also, it was verified that there is a significant difference (p < 0.05) between the means of mass fractions obtained in the control and in the exposed samples for most elements in both species. The T. usneoides showed higher enrichment actor of mass fractions than those obtained for the T. tipu barks for most elements, possibly due to the different mechanisms of pollutant retention between the two species. For T. tipu barks a single representative control sample for exposure was not used due to the variability of the elements content for bark collected from trees cultivated at the same sampling site, However, this difficulty was solved by using a control sample for each exposure point. The results indicated that there was accumulation if elements during exposure for most elements, and the correlation of these elements with possible sources of emission in both species was verified. From the results obtained, it can be concluded that the T. usneoides and the T. tipu barks can be used in the active biomonitoring of air pollution in urban areas. (author)