Monitoramento da ação de nanotubos de carbono sobre fungos liqueinizados epifíticos

Abstract

The development of nanoproducts and nanotechnology, despite current advances, still suffer from the lack of regulation for use, for environmental monitoring and security. The absence of environmental bioindicators is one of the technical obstacles to the adoption of mechanisms of legal regulation. In this scenario, this tesis proposes the study of lichenized fungi – classical biomonitors of atmospheric pollution - as biomonitors of carbon nanotubes (CNT) suspended in the air. For this, the lichen Parmotrema tinctorum was transplanted to Open Top Chambers (OTC) where they were exposed to carbon nanotubes aerosols. The following physiological parameters were measured after treatment: index of photobiont vitality, photosynthetic efficiency, membrane permeability and the distribution of chemical elements inside the thalus. We carried out also the study of the isolated photobiont, Trebouxia sp where growth, chlorophyll content and membrane damage were evaluated. The decrease in growth rate, the amount of chlorophyll of the isolated culture and cell membrane damage are the observed adverse effects. The photosynthetic activity (Fv/Fm) was not changed in any of the experiments and dose response effects were observed in a concentration range. Evidence of internalization and bioaccumulation of carbon nanotubes in the lichen and isolated photobiont are described. Our results point to the possibility of using the lichenized fungi as model organisms to be considered in the context of environmental risk assessment of nanoparticles.