Cladonia verticillaris (lÃquen) como biomonitor padrÃo da qualidade do ar no distrito de JaboatÃo-PE

AUTOR(ES)
DATA DE PUBLICAÇÃO

2002

RESUMO

Liquens are recognized as environmental bioindicators and biomonitors of air quality. In this research the District of JaboatÃo, Metropolitan Meso-region of Recife (MMR), Pernambuco, Brazil was selected for evaluating the air quality in that area, correlating data obtained from the biological monitors â liquens, with the results obtained in the stations of mechanical monitoring installed by the Environmental Company from Pernambuco State (CPRH). Lichen of the species Cladonia verticillaris (Raddi) Fr. was the used biomonitor. The species was collected in sandy soils of coastal savannah tipe vegetation (cerrado) of Paraiba State (NE of Brazil), in the following areas: Mamanguape, in the Biological Reservation of Guaribas, and in Alhandra, at the margins of BR 101 road. The active biomonitors were collected in and kept in plastic recipients, as well as the soil of occurrence area, their substratum. Experiments of transplant of the lichen material were kept on the stations of mechanical monitoring of CPRH located in the Subway Station (point 1) and other in the Companhia HidroelÃtrica do SÃo Francisco CHESF (point 2) in the studied district. The samples of both occurence areas were collected in March of 2000, and immediately exposed to the atmosphere in the experimental points. After 12 and 18 months exposition to the environmental pollutants, samples were removed and analyzed chemical and physiologicaly There were quantified by Inductively Coupled Plasma â Mass Spectometry (ICP/AES) the content of Pb, Cd, Fe, Cu, Mn, Zn, Cr, Ni and Ca. Part of the same samples were extracted with acetone until exhaustion, at room temperature (28Â Â 3Â C), and analyzed by Thin Layer Chromatography (TLC), and High Perfomance Liquid Chromatography (HPLC), for identification and quantification of the lichen phenols contained in the samples. Filters of high volume samples (Hil-vol) of CPRH were evaluated and determined the content of Pb, Cd, Fe, Cu, Mn, Cr, Zn and Ni. For this experiment there were considered the representative samples for largest monthly concentrations of Total Suspended Particles (TSP), whose filters were removed in the same period as the biomonitors. The heavy metals above mentioned were determined through Atomic Absorption Spectometry (AAS). The verification of the behavior exhibted by C. verticillaris, under laboratorial conditions, experiments were realized, where samples of the lichen were daily sprayed with lead acetate solutions at 1%, 0,1%, or deionized water as control group. Samples were collected to 24h, 48h 5 and 10 days, being later analyzed, according to the same parameters already referred for the material exposed to the environmental conditions. At the end, the more preserved samples, and the damaged ones, as from the field experiments as the laboratory, were analyzed by Scanning Eletronic Microscopy (SEM). The results demonstrated that all samples had lost the synthesis of phenols common of the species. Analyses in TLC and HPLC, proved the occurrence of different substances detected in the standard samples. HPLC analysis demonstrated that the pollutants harmed the synthesis of phenolics as in qualitative aspect (intermediary substances of the metabolic pathway), as in the total content of produced substances. It was evidenced the productio of protocetraric acid, besades the hypoprotocetraric acid and its aldehide, as intermediary products. It was suggested tha the low content of compounds, and/or the production of intermediary metabolites have beeen occured by damage in the photosynsthesis, by cell acidification by pollutants,the blocking of enzymatic reactions by elements that contamined the lichen, or tha association of these aspects. In relation to the quantification of the pollutants, the prevalence of Pb, Fe, Ca, Mn, Zn and Cr in the lichen samples was detected. In filters removed from mechanical monitoring the Fe, Cu, Mn and Zn were detected in highest amount. In the material submitted to the lead acetate, it was verified that the number of days of exposition (10) was enough for harming the lichen in physiological aspect. Analyses for Scanning Eletronic Microcopy (SEM) revealed a total disorder in the surface of the lichen thallus, after exposition to pollutants. The photobiont cells not visualized in the control samples were easily exposed, becoming unprotected under high level of pollutants influence. Similar data were obtained for the laboratorial experiments. C. verticillaris surface began exfoliation process resulting in its destruction. It was possible to conclude that the central zone of the city, near the subway station, is more polluted, and C. verticillaris, as biomonitor, had demonstrated capacity of registering the lowest levels of pollutants, including as bioacumulator of nutrients and toxic ionic elements, and in that context, has validating its use as one more parameter for evaluation of the environmental quality, especially of the atmospheric air

ASSUNTO(S)

biomonitor lÃquen jaboatÃo-pe monitoramento do ar biomonitor poluiÃÃo do ar air monitoring lead acetate cladonia verticillaris acetato de chumbo de chumbo administracao publica jaboatÃo-pe cladonia verticillaris air pollution lichen

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