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Abstract(s)
O estilo de vida atual provoca, em grande parte da população, preocupações, stress e depressões, o que tem levado a um aumento do consumo de antidepressivos na maioria dos países. Consequentemente tem aumentado a entrada destas substâncias, e dos seus metabolitos, no meio ambiente provenientes de descargas de águas residuais domésticas tratadas, pois os tratamentos convencionais não removem estes fármacos eficientemente, podendo causar efeitos prejudiciais nos ecossistemas.
Os objetivos deste trabalho foram a avaliação da ecotoxicidade de um psicofármaco e de alguns nanocatalisadores desenvolvidos para a remoção de fármacos através de tratamentos de fotoxidação catalítica, utilizando a microalga Pseudokirchneriella subcapitata.
Os ensaios foram realizados de acordo com o teste de inibição para algas, descrito no Regulamento CE 440/2008 da Comissão, de 30 de maio de 2008, que por sua vez, se baseia no documento “Guidelines for the Testing of Chemicals: Freshwater Alga and Cyanobacteria Growth Inhibition Test” (OECD, 2011). O princípio do teste baseia-se na determinação do efeito no crescimento de culturas de algas expostas a uma gama de concentrações de uma dada substância. A resposta é avaliada em função da concentração do material de exposição comparativamente a uma cultura de controlo. A duração dos ensaios foi de 72 h. Um ensaio prévio com uma substância de referência, o dicromato de potássio, serviu para demonstrar que, nas condições do ensaio, a sensibilidade da espécie de alga utilizada não se alterou significativamente. As culturas de controlo apresentaram uma taxa de crescimento de acordo com os valores de referência definidos pelo método. O crescimento da biomassa das culturas foi avaliado a partir da determinação do conteúdo de clorofila in vivo por fluorescência num leitor de microplacas. As curvas de inibição de crescimento em função do logaritmo da concentração testada foram traçadas com base na redução da fluorescência e as estimativas dos parâmetros ecotoxicológicos foram obtidas a partir das equações de regressão linear.
O psicofármaco selecionado para os ensaios foi a venlafaxina. Os nanomateriais testados foram o grafeno, os polioxometalatos (PMo10V2, PMo11V e PMo12) e os polioxometalatos imobilizados em flocos de grafeno (PMo10V2@GF, PMo11V@GF e PMo12@GF). Foram avaliadas as concentrações efetivas que causam 10, 20 e 50% de inibição na população de algas (CE10, CE20 e CE50) para todos os compostos testados. A venlafaxina foi classificada como substância tóxica para o ambiente aquático, bem como o PMo10V2 e o PMo10V2@GF. As substâncias prejudiciais para o ambiente aquático são o PMo11V e o PMo11V@GF. Os restantes materiais, grafeno, PMo12 e PMo12@GF, apresentam uma toxicidade mais baixa, sendo classificados como substâncias com possíveis efeitos prejudiciais para os organismos aquáticos.
Today's lifestyle raises concerns, stress and depressions to a large extent in the population, which has led to an increase in antidepressant consumption in most countries. As a consequence, the entrance of these substances and their metabolites in the environment due to discharges of treated domestic wastewaters has increased since conventional wastewater treatments do not efficiently remove these pharmaceuticals, which can cause harmful effects on ecosystems. The objectives of this work were to evaluate the ecotoxicity of a psychiatric drug and some nanocatalysts developed for the removal of pharmaceuticals through catalytic photooxidation treatments using the microalga Pseudokirchneriella subcapitata. The tests were carried out in accordance with the algae inhibition test described in Commission Regulation of European Community 440/2008 of May 30 2008, which was based in the document “Guidelines for the Testing of Chemicals: Freshwater Alga and Cyanobacteria Growth Inhibition Test” (OECD, 2011). The test principle is based on the determination of the effect on the growth of algae cultures exposed to a concentration range of a given substance. The response is evaluated as a function of the concentration of the exposure material compared to a control culture. The tests were carried out over a period of 72 h. A previous test with a reference substance, potassium dichromate, was performed to demonstrate that, under the test conditions, the sensitivity of the algal species did not change significantly. Control cultures showed a growth rate according to the reference values defined by the method. Growth of the biomass of the cultures was assessed from the determination of the in vivo chlorophyll content by fluorescence in a microplate reader. The growth inhibition curves were plotted as a function of the logarithm of the concentration tested on the basis of the fluorescence reduction. The ecotoxicological parameters effective concentration that causes 10, 20 and 50% inhibition to the algal population (EC10, EC20 and EC50) were estimated from the linear regression equations. The pharmaceutical selected for the trials was venlafaxine. The nanomaterials tested were graphene, polyoxometalates (PMo10V2, PMo11V and PMo12) and polyoxometalates immobilized on graphene flakes (PMo10V2@GF, PMo11V@GF and PMo12@GF). EC10, EC20 and EC50 were determined for all composites. Venlafaxine was classified as a toxic substance for the aquatic environment, as well as PMo10V2 and PMo10V2@GF. Substances harmful to the aquatic environment were PMo11V and PMo11V@GF. The remaining materials, graphene, PMo12 and PMo12@GF, had a lower toxicity and were classified as substances with possible harmful effects on aquatic organisms.
Today's lifestyle raises concerns, stress and depressions to a large extent in the population, which has led to an increase in antidepressant consumption in most countries. As a consequence, the entrance of these substances and their metabolites in the environment due to discharges of treated domestic wastewaters has increased since conventional wastewater treatments do not efficiently remove these pharmaceuticals, which can cause harmful effects on ecosystems. The objectives of this work were to evaluate the ecotoxicity of a psychiatric drug and some nanocatalysts developed for the removal of pharmaceuticals through catalytic photooxidation treatments using the microalga Pseudokirchneriella subcapitata. The tests were carried out in accordance with the algae inhibition test described in Commission Regulation of European Community 440/2008 of May 30 2008, which was based in the document “Guidelines for the Testing of Chemicals: Freshwater Alga and Cyanobacteria Growth Inhibition Test” (OECD, 2011). The test principle is based on the determination of the effect on the growth of algae cultures exposed to a concentration range of a given substance. The response is evaluated as a function of the concentration of the exposure material compared to a control culture. The tests were carried out over a period of 72 h. A previous test with a reference substance, potassium dichromate, was performed to demonstrate that, under the test conditions, the sensitivity of the algal species did not change significantly. Control cultures showed a growth rate according to the reference values defined by the method. Growth of the biomass of the cultures was assessed from the determination of the in vivo chlorophyll content by fluorescence in a microplate reader. The growth inhibition curves were plotted as a function of the logarithm of the concentration tested on the basis of the fluorescence reduction. The ecotoxicological parameters effective concentration that causes 10, 20 and 50% inhibition to the algal population (EC10, EC20 and EC50) were estimated from the linear regression equations. The pharmaceutical selected for the trials was venlafaxine. The nanomaterials tested were graphene, polyoxometalates (PMo10V2, PMo11V and PMo12) and polyoxometalates immobilized on graphene flakes (PMo10V2@GF, PMo11V@GF and PMo12@GF). EC10, EC20 and EC50 were determined for all composites. Venlafaxine was classified as a toxic substance for the aquatic environment, as well as PMo10V2 and PMo10V2@GF. Substances harmful to the aquatic environment were PMo11V and PMo11V@GF. The remaining materials, graphene, PMo12 and PMo12@GF, had a lower toxicity and were classified as substances with possible harmful effects on aquatic organisms.
Description
Keywords
Ecotoxicidade Grafeno Microalgas Nanomateriais Polioxometalatos Venlafaxina Ecotoxicity Graphene Microalgae Nanomaterials Polyoxometalates Venlafaxine