Toxic effects of emerging microcontaminants on planktonic food webs

Abstract

Nowadays, there is increasing concern with so-called emerging micropollutants, nanomaterials (NMs) or nanoparticles (NPs) (1 to 100 nm), with new properties that give them many technological applications, but its interaction with the aquatic biota is poorly understood. Studies addressing adverse effects of NPs on living organisms are essential to subsidize regulatory agencies in proposition of control legislation. In this sense, since the plankton is sensitive to pollutants and constitutes the base of aquatic food chains, the main objective of this project is to investigate the ecotoxicological effects of exposure of native planktonic species to different NPs (nano-TiO2, Fe2O3, FeCu, CuO , CdSe) and its physiological, biochemical and metabolic implications and assess its assimilation, transfer and bioaccumulation in tropical freshwater microbial chains. Our great challenge is the detection of chronic effects at different levels of biological organization (sub-cellular, individual, population and community), with sub-lethal contamination, especially through food. Besides the ecotoxicological assessments, physiological responses to cellular level of cytotoxicity (size, quantity of pigment, oxidative stress, cell viability) will be evaluated using flow cytometry. In physiological testing with microalgae, we will determine photosynthetic efficiency (Phyto-PAM) considering the photochemical decay, electron transport rate and carbon fixation. To evaluate the metabolism of test-organisms we will use micro respirometers with micro oxygen sensors of high performance (pico-ammeter) in microchambers incubation. In addition, we will investigate the impact of NPs on the biochemical composition (proteins, carbohydrates, total lipids and lipid classes - Iatroscan-TLC / FID) of the studied organisms. (AU)