Iron ore industry emissions as ecological risk factors for plant species of Anchieta restinga, Espírito Santo, Brazil / Emissões da indústria de minério de ferro como fatores de risco ecológico em espécies ocorrentes na restinga de Anchieta, Espírito Santo, Brasil

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The restinga vegetation of the Espírito Santo state coast is exposed to the pollutants emitted by iron ore industry, the iron ore solid particulate matter and the wet acid deposition. To investigate the possible effects of these pollutants on the vegetation, biochemical, physiological, and ecological processes were evaluated. For that matter five native species were assessed: Ipomoea pes caprae, Canavalia rosea, Sophora tomentosa, Guapira pernambucensis and Schinus terebinthifolius. Field monitoring revealed that plants located near the source of pollutants had greater iron content in the leaves, which might collaborate to phytotoxicity. Phenological results indicate that the reproductive aspects of these species, flowering and fruiting, can be negatively affected by the deposition of iron ore solid particulate matter, especially in S. tomentosa. In the germination and initial growth experiments it was observed that the exposure to acidity and iron ore solid particulate matter affected differently the species studied. The results reveal that G. pernambucensis and S. terebinthifolius presented a greater resistance, since the germination rate, the root tolerance index and the net gain of dry matter in these species remained unaffected even upon stress treatments, while S. tomentosa was significantly affected. The simulated deposition of iron ore solid articulate material and acid mist on the aerial portion of the plants induced an oxidative stress in S. tomentosa. In this species the photosynthetic rate was reduced, whereas the electrolytes leakage, the malondialdehyde and iron contents in the leaves increased. This situation was accompanied by a significant increase in the activity of antioxidant enzymes, superoxide dismutase and catalase. Conversely, plants of S. terebinthifolius were able to avoid the development of oxidative stress, in part due to its capacity to maintain a normal content of iron in the foliar tissue. These results allow the conclusion that the emissions from the iron ore industry can affect the restinga vegetation in its different organization, levels and as a long term consequence, alter its composition.

ASSUNTO(S)

restinga biomonitoring iron ecofisiologia vegetal poluição biomonitoramento restinga ferro pollution

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