RESUMO
The aim of this study was to evaluate the use of tree barks as a bioindicator of atmospheric pollution in areas of contrasting population densities and to associate the levels of elements found in this bioindicator with those obtained in fingernail samples collected from students living in the same study areas. Tree bark samples were collected from urban areas near highways in regions with high (Area A), intermediate (Area B), and low (Area C) population densities of Porto Alegre, Brazil, and evaluated for chemical elements concentration. Since these areas also differed in traffic density, NO2 was measured by passive sampling. For a comparative purpose, the elements were also determined in fingernail samples collected from students living in the same areas. Accumulated elements were determined by inductively coupled plasma mass spectrometry (ICP-MS) and principal component analysis (PCA) was used as a tool in exploratory data analysis to identify possible sources. We found that Ba, Cd, Co, Cu, Mg, Mn, Ni, Pb, Sb, Sr, V, and Zn were at higher concentrations in tree barks in Area A, while Cd, Co, Cu, Mg, Mn, Ni, and Sr were at higher levels in students' fingernails of Area A as well. Furthermore, concentrations of elements found in barks were associated with those identified in fingernails collected from students living in the same areas. PCA demonstrated that vehicular traffic explained 66.4 % of the variance in tree bark and 50.8 % of the variance in fingernails. NO2 levels were significantly different among the areas, what is consistent with their respective vehicular flow and population density. In conclusion, we found conformance of elements levels accumulated in barks and fingernails at three monitoring areas with different profiles. The amount of traffic-related elements accumulated appears to be associated with the degree of urbanization and vehicular flow. Overall, data suggests a relationship between fingernails and tree bark as bioindicators of exposure to metals from air pollution.
Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Metais/análise , Unhas/química , Casca de Planta/química , Adolescente , Poluição do Ar/análise , Brasil , Criança , Feminino , Humanos , Masculino , Densidade Demográfica , População UrbanaRESUMO
The extension of pollutant accumulation in plant leaves associated with its genotoxicity is a common approach to predict the quality of outdoor environments. However, this approach has not been used to evaluate the environmental quality of outdoor smoking areas. This study aims to evaluate the effects of environmental tobacco smoke (ETS) by assessing particulate matter 2.5 µm (PM2.5) levels, the pollen abortion assay, and trace elements accumulated in plant leaves in an outdoor smoking area of a hospital. For this, PM2.5 was measured by active monitoring with a real time aerosol monitor for 10 days. Eugenia uniflora trees were used for pollen abortion and accumulated element assays. Accumulated elements were also assessed in Tradescantia pallida leaves. The median concentration of PM2.5 in the smoking area in all days of monitoring was 66 versus 34 µg/m3 in the control area (P < 0.001). In addition, the elements Al, Cd, Cu, Ni, Pb, Rb, Sb, Se, and V in Tradescantia pallida and Al, Ba, Cr, Cu, Fe, Mg, Pb, and Zn in Eugenia uniflora were in higher concentration in the smoking area when compared to control area. Smoking area also showed higher rate of aborted grains (26.1 ± 10.7 %) compared with control (17.6 ± 4.5 %) (P = 0.003). Under the study conditions, vegetal biomonitoring proved to be an effective tool for assessing ETS exposure in outdoor areas. Therefore, vegetal biomonitoring of ETS could be a complement to conventional analyses and also proved to be a cheap and easy-handling tool to assess the risk of ETS exposure in outdoor areas.