No abstract

-the aims of this study were to determine imazapyr efficacy for floating macrophyte control and ecotoxicology for non-target organisms. For the floating macrophyte control efficacy tests were used the doses of 0,5; 1,0; 2,0; 2,5; 3,0; 3,5 and 4,0 L ha -1 and a control with 10 replicates. The acute toxicology for non-target organisms was estimated by lethal concentration 50% (LC50 and EC50). The floating macrophyte control efficacy was over 90%. Imazapyr was classified as moderately toxic for the following biomarkers: L. minor, H. eques, B. rerio, P. caudimaculatus, P. canaliculata, and P. mesopotamicus and lightly toxic for A. caroliniana. Thus, imazapyr herbicide is a tool with great potential to be used on floating macrophyte control (E. crassipes, P. stratiotes e S. molesta) in Brazil and this practice can be evaluated by the use of application biomarkers.Keywords: acute toxicology, biomarkers, aquatic plants management. de 0,5; 1,0; 2,0; 2,5; 3,0; 3,5 RESUMO -O objetivo deste estudo foi determinar a eficácia do imazapyr no controle de macrófitas flutuantes e a ecotoxicidade para organismos não alvos. Para os ensaios de eficácia de controle das macrófitas flutuantes, foram utilizadas as doses

Bacterial diseases cause tilapia's high‐mortality outbreak. This study investigated the toxicity of azithromycin (AZT), a macrolide antibiotic that has been considered a possible therapeutic drug for tilapia aquacultural use. The 48‐h acute toxicity (50% lethal concentration, LC50; 48 h) of AZT was determined for Oreochromis niloticus. Thereafter, fish were exposed to 0, 1, 50 and 100 mg L−1 AZT during 14 days (chronic exposure) and measured the haematological variables, the activity of superoxide dismutase, catalase, glutathione peroxidase, glutathione‐S‐transferase (GST) and the concentration of glutathione (GSH), protein carbonyl and lipid peroxidation in the liver; histopathology was analysed the liver, gills and kidneys. The LC50; 48 h was >100 mg L−1. No fish died during chronic exposure. Haematocrit and haemoglobin concentration increased in fish exposed to 50 and 100 mg L−1, and the total number of leucocyte and thrombocyte increased after exposure to 100 mg L−1 AZT, suggesting a stimulation of defence cell production. In the liver, the antioxidant enzyme activities did not change, but GST activity and the GSH level increased in fish exposed to 100 mg L−1 AZT. Oxidative stress did not occur. Histopathological index (HIL) indicates moderate liver damage; minor histological changes in the gill and no change in the kidneys. AZT was considered non‐toxic for O. niloticus after acute exposure and, although it causes moderated histopathology in the liver after chronic exposure, this antibiotic may be an alternative against bacterial infections, depending on its efficacy to control bacterial disease in fish.

Aquatic macrophytes are important components of aquatic ecosystems, but these plants have become a problem due to their occurrence in different regions. Some studies aimed to demonstrate the effectiveness of herbicides to control these macrophytes; however, few studies report the possible ecotoxicological effects. The objective of this study was to estimate the acute toxicity (LC (I)50;96h) and assess water quality variables for glyphosate in the Rodeo ® formulation, Aterbane ® BR surfactant and mixtures of glyphosate + 0.5% and 1.0% of surfactant, for the guaru fish (Phallocerus caudimaculatus). The guaru was exposed to increasing concentrations of glyphosate and a mixture of glyphosate + 0.5 and 1.0% of surfactant. The mixture of glyphosate and glyphosate + 0.5 and 1.0% of surfactant showed (LC (I)50;96h) > 975.0 mg L -1 . For the surfactant, the rate was 5.81 mg L -1 . The glyphosate and mixtures of glyphosate + 0.5% and 1.0% of surfactant caused a decrease in pH and dissolved oxygen and increased the electrical conductivity of water. Glyphosate in the Rodeo ® formulation and the mixtures with surfactant Aterbane ® BR can be classified as practically nontoxic, whereas surfactant Aterbane ® BR can be considered as moderately toxic to guaru. RESUMO. Ecotoxicologia do glifosato e surfactante aterbane ® br para guaru (Phalloceros caudimaculatus).As macrófitas aquáticas são importantes componentes dos ecossistemas, porém elas têm se tornado um problema pela sua ocorrência em diversas regiões. Alguns estudos visam comprovar a eficácia dos herbicidas no controle dessas macrófitas, porém, poucos trabalhos relatam os possíveis efeitos ecotoxicológicos. Assim, o objetivo deste trabalho foi estimar a toxicidade aguda (LC (I)50;96h) e avaliar as variáveis de qualidade de água para o glifosato na formulação Rodeo ® , o surfactante Aterbane ® BR e das misturas de glifosato + 0,5 e 1,0% do surfactante, para o peixe guaru (Phallocerus caudimaculatus). Para tanto, o guaru foi exposto a concentrações de glifosato e da mistura do glifosato + 0,5 e 1,0% do surfactante. O glifosato e a mistura do glifosato + 0,5 e 1,0% do surfactante apresentaram (LC (I)50;96h) > 975,0 mg L -1 . Para o surfactante, foi de 5,81 mg L -1 . O glifosato e as misturas de glifosato + 0,5 e 1,0% de surfactante causaram diminuição do pH e do oxigênio dissolvido e aumento da condutividade elétrica da água. O glifosato na formulação Rodeo ® e as misturas com surfactante Aterbane ® BR podem ser classificados como praticamente não-tóxicos, enquanto que o surfactante Aterbane ® BR pode ser considerado como moderadamente tóxico para o guaru.Palavras-chave: peixe tropical, toxicidade, herbicida.

Os surfactantes são moléculas anfipáticas que reduzem a tensão superficial da água e fazem parte dos componentes inertes das formulações de produtos fitossanitários. Assim, os objetivos deste trabalho foram: estimar a concentração letal (CL(I)(50;96h)); classificar e avaliar a qualidade da água durante os testes de toxicidade aguda dos surfactantes: Agral ® , Aterbane ® BR, Ag-Bem ® , Energic ® , Fixade ® e Gotafix ® para o peixe mato grosso (Hyphessobrycon eques); e os sinais de intoxicação nos animais. Para tanto, os peixes foram aclimatados por dez dias em sala de bioensaio. Os animais foram expostos aos surfactantes em DIC com três repetições. A CL(I)(50;96h) do surfactante Agral ® foi 3,29 mg L-1 ; do Aterbane ® BR, 8,21 mg L-1 ; do Energic ® , 2,34 mg L-1 ; do Gotafix ® , 4,37 mg L-1 ; do Fixade ® , 3,38 mg L-1 e do Ag-Bem ® , 34,95 mg L-1. As variáveis de qualidade da água não foram alteradas. Os peixes apresentaram aumento do batimento opercular após a exposição; 4 e 24h, perda da capacidade de arfagem; 48h, batimento opercular lento e 72 e 96h, recuperação. Os surfactantes Energic ® , Agral ® , Gotafix ® , Aterbane ® BR e Fixade ® podem ser classificados como moderadamente tóxicos e o Ag-Bem ® como pouco tóxico para H. eques e este organismo apresenta sinais de intoxicação semelhantes para todos os surfactantes. Palavras-chave: ecotoxicologia, peixe, qualidade de água, comportamento. ABSTRACT. Toxic effects of phytosanitary surfactants for jewel tetra (Hyphessobrycon eques). Surfactants are amphipatic molecules that reduce the surface tension of water and make up the inert components of pesticide formulations. Thus, the objectives of this study were: to estimate the lethal concentration (LC(I)50;96h); classify and evaluate water quality during testing of the following surfactants: Agral ® , Aterbane ® BR, Ag-bem ® , Energic ® , Fixade ® and Gotafix ® for jewel tetra (Hyphessobrycon eques); and the signs of intoxication in the animals. For this, the fish were acclimated for ten days in the bioassay room. The animals were exposed to the surfactants in an entirely randomized design with three replications. The LC(I)(50;96h) of surfactant Agral ® was 3.29 mg L-1 ; Aterbane ® BR 8.21 mg L-1 ; Energic ® 2.34 mg L-1 ; Gotafix ® 4.37 mg L-1 ; Fixade ® 3.38 mg L-1 ; and Ag-bem ® 34.95 mg L-1. The variables of water quality were unchanged. The fish showed an increase in the opercular beating after exposure; 4 and 24 hours, loss of gasping ability; 48 hours, slow opercular beating; and 72 and 96 hours later, recovery. The surfactants Energic ® , Agral ® , Gotafix ® , Aterbane ® BR and Fixade ® can be classified as moderately toxics, and Ag-Bem ® as slightly toxic for H. eques; this organism shows similar intoxication signs for all surfactants.

No abstract

Natural insecticides from plant extracts represent an alternative to the highly toxic synthetic products in order to reduce environmental contamination; however some might also be toxic for nontarget organisms. The present study determined the 50% lethal concentration (48h; LC50) for adults Nile tilapia (Oreochromis niloticus) exposed to the natural insecticide Fumydro ® , based on the tobacco plant (Nicotiana tabacum), and evaluated its effect on hematological variables. After preliminary tests, adult specimens of O. niloticus were exposed to four Fumydro ® concentrations (200, 300, 400 and 500 μL L-1). The 48h; LC50 of Fumydro ® was determined at 370 ± 50 μL L-1. The surviving fish after exposure to Fumydro ® showed an increase in the number of red blood cells, hemoglobin concentration, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. The number of thrombocytes and leukocytes has not changed, unlike the differential leukocyte count that presented an increased percentage of neutrophils. The results indicated that the insecticide Fumydro ® is highly toxic to Nile tilapia and changes in erythrocyte variables suggested the induction to hypoxemia with low effect on the immune system.