890 resultados para DAPHNIA-MAGNA STRAUS


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Part IIA of the Environmental Protection Act 1990 requires environmental regulators to assess the risk of contaminants leaching from soils into groundwater (DETR, 1999). This newly introduced legislation assumes a link between soil and groundwater chemistry, in which rainwater leaches contaminants from soil into the saturated zone. As the toxicity of both groundwater and overlying soils is dependent upon the chemicals present, their partitioning and their bioavailability, similar patterns of soil, leachates and groundwater toxicity should be observed at contaminated sites. Soil and groundwater samples were collected from different contaminated land sites in an urban area, and used to determine relationships between soil chemistry and toxicity, mobility of contaminants, and groundwater chemistry and toxicity. Soils were leached using water to mimic rainfall, and both the soils and leachates tested using bioassays. Soil bioassays were carried out using Eisenia fetida, whilst groundwater and leachates were tested using the Microtox(TM) test system and Daphnia magna 48 h acute tests. Analysis of the bioassay responses demonstrated that a number of the samples were toxic to test organisms, however, there were no significant statistical relationships between soil, groundwater and leachate toxicity. Nor were there significant correlations between soil, leachates and groundwater chemistry.

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Three species of phylogenetically related semi-terrestrial crabs (Superfamily Grapsoidea - Sesarma rectum, Goniopsis cruentata and Neohelice granulata (formerly: Chasmagnathus granulatus) with different degrees of terrestriality were studied to quantify the accumulation of copper (Cu) in hemolymph, gills, hepatopancreas and antennal gland, and its excretion through the faeces. These crabs were fed for 15 days practical diets containing 0 (A), 0.5 (B), 1.0 (C), and 1.5% (D) of added CuCl2 (corresponding to 0, 0.2, 0.5 and 0.7% of Cu2+, respectively). The amount of food ingested was directly proportional to the degree of terrestriality: S. rectum, the most terrestrial species, ate around 2-3 times more than the other crabs, whereas G. cruentata ate 1.5-2 times more than N. granulata, the least terrestrial. The amount of Cu excreted in the feces was proportional to Cu ingestion, and was 76.8% and 64.2% higher for Sesarma fed diet D compared to G. cruentata and N. granulata, respectively. Sesarma also displayed higher Cu concentration in the haemolymph, gills and antennal glands, but not in the hepatopancreas. A detoxifying mechanism followed by elimination was probably present at this last organ, preventing Cu accumulation. More terrestrial crabs, such as Sesarma, may accumulate more Cu in hemolymph and tissues, showing a correlation between metal accumulation and increased terrestriality. In this aspect, contaminated feed sources with Cu may have more impact in conservation of terrestrial crabs. (C) 2008 Elsevier Inc. All rights reserved.

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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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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Aquicultura - FCAV

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Pós-graduação em Aquicultura - FCAV

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The aims of this research were to evaluate the acute toxicity (LC/EC50) and the environmental risk of toltrazuril (TOL) and florfenicol (FFC) for plant Lemna minor, snail Pomacea canalicuta, fish Piaractus mesopotamicus and Hyphessobrycon eques and the microcrustacean Daphnia magna. The organisms were acclimated in room bioassay with controlled temperature according to standard to each one. They were exposed at nominal concentrations in static system. For environmental risk (RQ) was used the estimated environmental concentration (EEC) that is the dosage indicate to treatment and the lethal or effective concentration (LC/CE50) from each drug in acute exposure. FFC showed LC50;7d of 97.03 mg L-1 for L. minor; >100.0 mg L-1 for P. mesopotamicus and H. eques and EC50;48h > 100.0 mg L-1 for P. canaliculata and D. magna, and it was classified low risk (RQ = 0.01) for all bioindicators. TOL howed LC50;7d >100.0 mg L-1 for L. minor, 3.72 mg L-1 for P. mesopotamicus; 6.22 mg L-1 for H. eques and CE50;48h of 7.59 mg L-1 for P. canaliculata and 18.57 mg L-1 for D. magna, and it was classified low risk (RQ = 0.01) for L. minor and high risk for P. mesopotamicus (RQ = 2.68), H. eques (RQ = 6.22), P. canaliculata (RQ = 1.31) and D. magna (RQ = 0.53). Lemna minor was the bioindicator indicating of FFC toxicity and H. eques, bioindicator of the TOL. FFC is safety however and the use of TOL necessaries cautions to treat the wastewater before discard on the environment.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)