Nádia Hortense Torres

Determination of pesticide residues in tomato using dispersive solid-phase extraction and gas chromatography/ion trap mass spectrometry

Tomato crop is frequently damaged by diseases, pests and abiotic stresses, resulting in lower yielding and loss of fruit quality. The intensive use of pesticides in tomatoes without observation of good agriculture practices and regulations has caused great concern with a probable final product contamination. The QuEChERS method of sample preparation was used for the determination of six pesticides (buprofezin, carbofuran, endosulfan-α, endosulfan-β, endosulfan sulfate and monocrotophos) in thirty three tomato samples collected from local market retailers. The method involved extraction with acetonitrile, liquid-liquid partition with addition of MgSO4 and NaCl followed by dispersive solid phase extraction using primary secondary amine sorbent and the analyses were carried out with a gas chromatography/mass spectrometry equipment by ion trap. Recovery studies for different pesticides ranged from 71 to 111% and the relative standard deviation (RSD) was below 15%. No pesticide residue was detected (> LOD) among the thirty three tomato samples analysed.

Analysis and occurrence of residues of the hormones estriol, 17α- ethinylestradiol and 17β-estradiol in urban water supply by HPLC-DAD

Hormones 17α-ethinylestradiol, 17β-estradiol and estriol were analyzed in urban water supply due to the concern about the problem associated with the presence of these compounds in water bodies. The aims of this project were adapt, validate analytical methodology and monitor these hormones in drinking water. Results showed that the limits of detection, linearity, regression coefficients and recoveries were suitable for the method and no contamination was detected in samples analyzed.

PISCICULTURA EM TANQUES-REDE: IMPACTOS E CONSEQUÊNCIAS NA QUALIDADE DA ÁGUA

RESUMO: A piscicultura com sistema de cultivo em tanques-rede e uma atividade que vem se destacando no cenario brasileiro principalmente devido a sua flexibilidade de manejo e baixo custo. No entanto, este tipo de sistema de producao de peixes pode provocar impactos nos ecossistemas aquaticos e alterar a qualidade da agua e prejudicar a qualidade do pescado produzido. O presente artigo teve como objetivo realizar uma revisao de literatura sobre os principais aspectos relacionados a piscicultura em tanques-rede, a influencia desta atividade nos parâmetros limnologicos de qualidade da agua e seus possiveis impactos ambientais. Os topicos abordados na revisao incluem a caracterizacao das pisciculturas em tanques-rede, a relacao entre esta atividade e a qualidade da agua e os impactos provocados por este sistema de cultivo. De acordo com a pesquisa bibliografica, as alteracoes provocadas pela producao de peixes em tanques-rede incluem aporte de nutrientes na agua que podem causar eutrofizacao do meio, introducao de especies exoticas que possam comprometer a biota nativa e uso de antibioticos que propiciem o desenvolvimento de bacterias patogenicas resistentes. Assim, a producao de organismos aquaticos em tanques-rede deve buscar a sustentabilidade preocupando-se com a preservacao do ambiente atraves de tecnologias que minimizem seus impactos negativos e otimizem o processo de producao ao mesmo tempo que proporcione lucro para seus produtores. Palavras-chave: Aquicultura. Ecossistemas aquaticos. Nutrientes.

Characterization of a tubular electrochemical reactor for the degradation of the commercial diuron herbicide

ABSTRACT After designing and constructing an electrochemical reactor with concentric electrodes and tangential feed (RECT), it is necessary to characterize it and to study its performance. The experimental study of the residence time distribution (RTD) was conducted for flow rates of 2.78 × 10–6 m3 s–1, 8.33 × 10–6 m3 s–1 and 13.9 × 10–6 m3 s–1. According to the values obtained from the Pe number (0.67–1.52), the RECT fits as tubular with great dispersion. The determined empirical correlation (Sh = 18.16 Re0.50 Sc0.33) showed a laminar flow behavior in the range of Reynolds number (Re) between 23 and 117. In order to use RECT in effluent treatment, an electrochemical oxidation study of the Diuron model molecule (Nortox®) was performed to analyze reactor performance in a closed system with total reflux. A decay kinetics of pseudo-first order was associated with the decay of the concentration of diuron and 30% mineralization in 180 min of process were obtained, having a total volume of 4 × 10–3 m3 and an initial concentration of commercial Diuron in 215.83 mg dm–3. Eleven by-products were identified by HPLC–MS analysis and, from this, it was possible to propose a route of degradation of the diuron. From these observations, it can be inferred that the studied electrochemical reactor had applicability in the degradation of recalcitrant compounds, as is the case of commercial diuron. Make some changes in the electrochemical reactor studied and other advanced oxidative processes, such as electro-Fenton, can be associated with the studied system to achieve a better conversion efficiency. GRAPHICAL ABSTRACT

Protistas ciliados e seu potencial uso como bioindicadores de qualidade de água

RESUMO: A contaminacao dos ecossistemas aquaticos por substâncias quimicas provenientes de atividades agricolas inadequadas e do despejo irregular de efluentes tem se intensificado. Assim, e indispensavel o uso de organismos que possam indicar a presenca desses contaminantes ou a qualidade dos corpos hidricos. O objetivo do presente trabalho foi realizar uma revisao de bibliografica sobre os aspectos gerais dos protistas ciliados ressaltando a importância da utilizacao desses organismos como bioindicadores em estudos de monitoramento de qualidade de agua e em ensaios de ecotoxicidade com contaminantes aquaticos. De acordo com essa pesquisa, os protistas ciliados sao excelentes organismos para serem utilizados como bioindicadores de qualidade de agua em programas de monitoramento devido a sua abundância, ciclo de vida curto, sensibilidade as alteracoes fisicas, quimicas e biologicas no ambiente aquatico, facilidade de manutencao em laboratorio e prevalencia em corpos hidricos. Os estudos com esses ciliados podem ser focados tanto em analises da diversidade, riqueza e abundância de especies em ecossistemas aquaticos como em avaliacoes da ecotoxicidade de contaminantes que podem atingir corpos d´agua. Nos estudos de monitoramento da qualidade de agua que incluem determinacao da riqueza, abundância e diversidade em ambientes impactos as especies identificadas podem variar de uma regiao para outra, enquanto que em ensaios laboratoriais de toxicidade as especies dos generos Tetrahymena e Paramecium sao internacionalmente as mais utilizadas. PALAVRAS-CHAVE: Protozoarios. Ecotoxicidade. Paramecium . Contaminantes. Ciliated protists and its potencial use as bioindicators of water quality ABSTRACT: Contamination of aquatic ecosystems by chemicals from inadequate agricultural activities and irregular effluent disposal has intensified. Thus, the use of organisms that may indicate the presence of these contaminants or the quality of the water bodies is indispensable. The objective of the present paper was to perform a literature review on the general aspects of ciliate protists emphasizing the importance of using these organisms as bioindicators in water quality monitoring studies and in aquatic contaminant ecotoxicity tests. According to this research, ciliary protists are excellent organisms to be used as bioindicators of water quality in monitoring programs due to their abundance, short life cycle, sensitivity to physical, chemical and biological changes in the aquatic environment, ease of maintenance In laboratory and prevalence in water bodies. Studies with these ciliates can be focused on analyzes of the diversity, richness and abundance of species in aquatic ecosystems as well as evaluations of the ecotoxicity of contaminants that can reach bodies of water. In water quality monitoring studies that include determination of richness, abundance and diversity in impacted environments the identified species may vary from one region to another, whereas in laboratory toxicity tests the species of the genera Tetrahymena and Paramecium are internationally most used . KEYWORDS: Protozoa. Ecotoxicity. Paramecium. Contaminants Protistas ciliados y su uso potencial como bioindicadores de la calidad del agua RESUMEN: La contaminacion de los ecosistemas acuaticos por los productos quimicos provenientes de las actividades agricolas inadecuadas y la descarga irregular de efluentes se ha intensificado. Por lo tanto, el uso de organismos que pueden indicar la presencia de estos contaminantes o la calidad de los cuerpos de agua es indispensable. El objetivo de este estudio fue realizar una revision de la literatura sobre los aspectos generales de los protistas ciliados que enfatizan la importancia de usar estos organismos como indicadores biologicos en estudios de monitoreo de calidad del agua y las pruebas de ecotoxicidad con los contaminantes acuaticos. De acuerdo con esta encuesta, los protistas ciliados son excelentes organismos para ser usados como bioindicadores de la calidad del agua en los programas de vigilancia debido a su abundancia, corto ciclo de vida, sensibilidad a los cambios biologicos en el medio ambiente acuatico fisica, quimica y facilidad de mantenimiento, laboratorio y prevalencia en los cuerpos de agua. Los estudios con estos ciliados pueden centrarse tanto en el analisis de la diversidad, riqueza y abundancia de las especies en los ecosistemas acuaticos como las evaluaciones de la ecotoxicidad de los contaminantes que pueden llegar a los cuerpos de agua. En los estudios de vigilancia de la calidad del agua, incluyendo la determinacion de la riqueza, abundancia y diversidad de ambientes impactos especies identificadas pueden variar de una region a otra, mientras que en el laboratorio de pruebas de toxicidad de especies de generos Tetrahymena y Paramecium son los mas utilizados a nivel internacional . PALABRAS-CLAVE: Protozoos. Ecotoxicidad. Paramecium. Contaminantes.