83 resultados para River water


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Feeding, seasonal changes in visceral fat and condition factor were compared in two species of characidiin fishes, Characidium lauroi and C. alipioi from Ribeirão Grande system, southeastern Brazil. Five streams of Ribeirão Grande system were sampled (22° 47' 08 S, 45° 28' 17W). The samples were taken four times per site, from July, 2001 to April, 2002: winter (July 2001), spring (October 2001), summer (February 2002) and autumn (April 2002). Quantitative collections were made with an electro-fishing device powered by a generator with maximum capacity of 1,500 V and 8.7 A of 60 Hz alternating current. Ephemeroptera nymphs, Diptera larvae (Chironomidae, Simuliidae), Plecoptera nymphs, Trichoptera larvae (Hydroptilidae, Psychoyiidae), terrestrial insects (Coleoptera, Isoptera, Hemiptera [Heteroptera, Homoptera]), Megaloptera larvae (Corydalidae), Arachnida, Ostracoda and vegetal debris were found in both species' diets. Visceral fat declined in February, coinciding with the decline of the condition factor in both species. The increased feeding from summer to fall provides fat accumulation. During subsequent seasons, fish may utilize visceral fat reserves for maintenance and reproduction.

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This study evaluated the water quality of the Vargem Limpa stream and tested the hypothesis that protected stretches of the aquatic system, located within a conservation unit, favor the preservation of the diversity of Chironomidae (Insecta: Diptera). Samplings were conducted in four stations, where some physical and chemical variables were measured. The results obtained by the study indicated the predominance of genera associated with arenaceous substrata, and that the stretches protected by the conservation unit presented better environmental conditions, with better-preserved Chironomidae diversity, demonstrating the importance of these areas in maintaining the diversity of Chironomidae.

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The environmental analysis is an important tool used in forecasting and mitigation of environmental problems. Focusing on the occupation of marginal areas of the Corumbataí River in an urban stretch in the city of Rio Claro (SP), this study aimed to gather information on situations of risk, both to the environment and the population, verified in that area. Through field observation and in specific studies, the geological and geotechnical aspects, the characteristics of surface waters and aspects of urbanization were analyzed. The results show that the environmental problems diagnosed are related to lack of planning in the occupation of the area. Moreover, the natural characteristics of the physical environment expose people to risks such as floods and soil slides.

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A dynamic systems water resources simulation model was developed as a tool to help to analyze water resources management alternatives for the Piracicaba, Capivari and Jundiaí River Water Basins (BH-PCJ). Different politics policy were simulated for 40-year. The model estimates water supply and demand, as well as contamination load from several consumers. Six runs were performed using average precipitation value, changing water supply and demand, and different volumes diverted from BH-PCJ to BH-Alto Tietê For the Business as Usual, the Sustainability Index went from 0.41 in 2010 to 0.22 by 2050; the Water Use Index changed from 80.7% in 2010, to 125.5% by 2050; and the Falkenmark Index changed from 1,302 m 3 person -1 year -1 in 2010 to 774 m 3 P -1 year -1 by 2050. It was noticed that sanitation is one of the biggest concerns in the near future at PCJ River Basin.

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A biomimetic sensor based on a carbon paste electrode modified with the nickel(II) 1,4,8,11,15,18,22,25-octabutoxy-29H,31H-phthalocyanine complex was developed as a reliable alternative technique for the sensitive and selective analysis of the herbicide diuron in environmental media. The sensor was evaluated using cyclic voltammetry and amperometric techniques. The best amperometric responses were obtained at 750 mV vs. Ag/AgCl (KClsat), using 0.1 mol L-1 phosphate buffer solution at pH 8.0. Under these conditions, the sensor showed a linear response for diuron concentrations between 9.9 × 10-6 and 1.5 × 10-4 mol L -1, a sensitivity of 22817 (±261) μA L mol-1, and detection and quantification limits of 6.14 × 10-6 and 2 × 10-5 mol L-1, respectively. The presence of the nickel complex in the carbon paste improved selectivity, stability, and sensitivity (which increased 700%), compared to unmodified paste. The applicability of the sensor was demonstrated using enriched environmental samples (river water and soil). © 2012 Elsevier B.V. All rights reserved.

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Endocrine disruptors (EDs) are widespread in the environment, especially aquatic systems, and cause dangerous effects on wildlife and humans. This work was aimed to assess the capacity of radish (Raphanus sativus L.) and ryegrass (Lolium perenne L.) seedlings to tolerate and remove two combinations of EDs containing bisphenol A (BPA), 17α-ethynilestradiol (EE2), and linuron from four aqueous media: distilled water, a solution of natural organic matter (NOM), a lake water and a river water. Seeds of the two species were germinated in each contaminated medium and, at the end of germination, the seedling growth was evaluated by biometric measurements and residual EDs were quantified by chromatographic analysis. Biometric measurements revealed that the phytotoxicity of the two combinations of EDs depended on the medium used. Radish showed a discrete tolerance in distilled water and lake water but was inhibited in the solution of NOM and river water. Ryegrass was negatively affected mainly in river water. The concentration of each ED appeared significantly reduced in all media in the presence of seedlings of both species, but not in the blanks without plants. In 5 days, radish removed up to 88% of BPA, 100% of EE2 and 42% of linuron, and in 6 days ryegrass removed up to 92% of BPA, 74% of EE2 and 16% of linuron. The considerable removal capacity of radish and ryegrass in all media tested encourages the use of phytoremediation to remove EDs from waters. © 2013 Copyright Taylor and Francis Group, LLC.

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Pós-graduação em Aquicultura - FCAV

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Química - IQ

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Geografia - IGCE

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)