Kairomones are infochemicals that benefit a heterospecific receiver. Chaoborus spp. release a kairomone from their gut when feeding on Daphnia spp. Daphnia respond to kairomone by shifting life history parameters or producing neonates with induced morphological defenses, increasing their chance of survival. When laboratory-cultured Daphnia are exposed to environmentally-relevant metal concentrations, a kairomone response is not induced, increasing predation vulnerability. Currently Daphnia live in metal-contaminated lakes in Sudbury, ON. It is possible the extant population is tolerant of relatively high copper (Cu) concentrations and can still induce a kairomone response. In comparison, it is hypothesized clones found in lakes isolated from anthropogenic sources of metal-contamination would be less tolerant as they have not been exposed to high Cu concentrations. The purpose of this study was to examine how multiple clones of D. pulicaria obtained from lakes along a Cu gradient respond to kairomone in the absence and presence of copper. Several different clones from Ontario lakes located in the Canadian Shield were exposed to environmentally-relevant Cu concentrations and Chaoborus kairomone. Neonates were collected and measured to assess predator-induced defenses. Results indicate that kairomone-mediated responses and Cu-tolerance vary among D. pulicaria clones. Clones from the Sudbury area were able to induce a response to kairomone when exposed to Cu, indicating a Cu-tolerance. However, this was not true for all Sudbury clones. In contrast, most clones from clean lakes did not respond to kairomone when exposed to Cu; while some clones exhibited a Cu-tolerance. Clones that were not tolerant of Cu were affected at concentrations much lower than those predicted by the Biotic Ligand Model (BLM) that induce acute toxicity. Predictions generated by the BLM can be conservative making them useful when creating water quality criteria; however, my results indicate these predictions can also be under-protective. Chemosensory cues mediate vital life processes that are essential for survival. Populations may be devastated if metals interfere with chemosensory cues. Overall, the results of my study suggest that genetic variation is important for population establishment and maintenance, specifically when exposed to multiple stressors, and that directional selection may result in stress tolerance. / Thesis (Master, Biology) -- Queen's University, 2009-12-23 09:50:46.152

Thesis (Ph.D.)--Baylor University, 2006. / Includes bibliographical references (p. 93-103).

Thesis (M. Sc.), Memorial University of Newfoundland, 1998. / Restricted until November 1999. Bibliography: leaves 93-110.

Thesis (M.S.)--The University of North Carolina at Greensboro, 2010. / Directed by Anne Hershey; submitted to the Dept. of Biology.

Techn. Universiẗat, Diss., 2002--Dresden.

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Química, Florianópolis, 2011 / Made available in DSpace on 2012-10-26T06:55:53Z (GMT). No. of bitstreams: 0 / O Bacillus thuringiensis var. israelensis (Bti) é uma bactéria entomopatogênica, Gram-positiva, aeróbica facultativa, formadora de esporos que, durante a esporulação, sintetiza um cristal protéico parasporal (?-endotoxina) em adição ao endósporo, tóxico a uma grande variedade de insetos que são economicamente importantes como pestes. Sua ação depende da ingestão dos cristais, que são solubilizados no intestino de larvas susceptíveis, onde as protoxinas são liberadas, formando poros na membrana, causando a morte da larva. Ele tem sido utilizado em Joinville e região para o controle dos mosquitos Aedes aegypti e Simulium pertinax, cujos ataques causam sérios impactos e inconveniência à população ribeirinha e ao turismo local. O objetivo do presente estudo é testar a metodologia de cultivo semi-contínuo para a produção de Bacillus thuringiensis var. israelensis proposta por Silva (2007); desenvolver uma formulação bioinseticida contendo o Bti obtido e verificar sua eficácia no controle populacional de larvas de A. albopictus em comparação com os bioinseticidas comerciais Vectobac AS e Teknar HP-D , bem como sua segurança em testes de toxicidade aguda utilizando, como bioindicadores, organismos não-alvo de diferentes níveis tróficos: o flagelado Euglena gracilis, representando os produtores primários, o microcrustáceo Daphnia similis, representanto os consumidores secundários e o peixe Danio rerio como representante dos consumidores terciários. Sob as condições experimentais utilizadas, a formulação bioinseticida produzida demonstrou ser eficiente para o controle de larvas de A. albopictus, com valores de DL50 de 3,97 mg/L, enquanto que os produtos comerciais formulados Vectobac AS e Teknar HP-D , tiveram valores de DL50 de 0,019 e 0,013 mg/L respectivamente. O bioinseticida Bti-Univille formulado demonstrou ser mais seguro ao organismo não-alvo Daphnia similis (DL50= 130 mg/L) que os produtos comerciais Vectobac AS® (DL50= 50 mg/L) e Teknar HP-D® (DL50= 32 mg/L), requerendo doses maiores para causar a mesma letalidade. Para todas as formulações bioinseticidas testadas, os valores de DL50 à D. similis foram superiores aos de DL50 estimados para o inseto-alvo; frente ao peixe Danio rerio, nenhuma das amostras bioinseticida testadas demonstrou toxicidade em doses até 100 mg/L. Os resultados obtidos nos ensaios de toxicidade aguda com Euglena gracilis foram inconclusivos, sendo necessária a realização de novos testes sob as mesmas condições experimentais para estimar a toxicidade do bioinseticida produzido a este organismo não-alvo.

Dissertação (mestrado) - Universidade Federal de Santa Catarina. Centro Tecnológico. Programa de Pós-Graduação em Engenharia Ambiental. / Made available in DSpace on 2012-10-22T12:54:22Z (GMT). No. of bitstreams: 1 230242.pdf: 1405379 bytes, checksum: 6c840d1d71fe32bd28213637ddba75f0 (MD5) / Devido às suas características, percolados de aterros sanitários necessitam tratamento antes de serem descartados no ambiente. Este tratamento, por vezes, inclui a desinfecção por cloração. A avaliação do percolado através de testes toxicológicos fornece informações seguras dos efeitos do mesmo sobre a biota aquática e vem a complementar o monitoramento físico e químico usual. O objetivo desta pesquisa foi desenvolver a análise de oxicidade crônica com Daphnia magna, e aplicá-la para avaliar a toxicidade crônica do efluente tratado de um aterro sanitário, comparando os efeitos crônicos do efluente clorado e não clorado sobre o organismo-teste. Observou-se que o efluente tratado antes da cloração não apresenta toxicidade aguda ou crônica ao organismo-teste, revelando um tratamento eficiente. Contudo, quando este efluente é clorado em laboratório a uma concentração de 2,3µL.L-1 de NaClO, simulando a real dosagem de cloro no aterro sanitário, o efluente, apesar de não apresentar toxicidade aguda, apresenta CEO=100% e CENO=80%. Já o efluente tratado com cloração na concentração 23µL.L-1 demonstrou ausência de toxicidade aguda, mas CEO=40,96% sendo que a CENO não foi possível determinar nas condições de teste. A toxicidade crônica foi diretamente proporcional à concentração de cloro no efluente. Ainda, em termos toxicológicos, a qualidade do efluente sem cloração é superior àquele clorado. Percolated liquids of sanitary landfills are potentially toxic, thus they need to be treated before being discarding in the environment. This treatment might include disinfection by chlorination. The evaluation of the leachate through toxicological tests allows disclosing information of the exact effect on the aquatic biota and comes as a complement to the physical and chemical monitoring usually used. The objectives of this research were to develop the chronic toxicological test with Daphnia magna to evaluate the chronic toxicity of treated effluents from a sanitary landfill. This was done by comparing the chronic effect of chlorinated and non-chlorinated effluents. The treated effluent before chlorination did not present acute or chronic toxicity to the test organism, indicating the efficiency of the treatment plant. However, when this effluent was chlorinated in laboratory to a concentration of 2.3µL.L-1 NaClO, simulating the dosage of chlorine in sanitary landfills, it showed no acute toxicity, but had a Lwest-Observed Effect Concentration (LOEC) of 100% and a No Observed Effect Concentration (NOEC) of 80%. The treated effluent with chlorination in the concentration of 23µL.L-1 NaClO had no acute toxicity, but presented a LOEC of 40.96%, while the NOEC was not possible to determine under the test conditions. The increase in chronic toxicity was proportional to the chlorine concentration in the effluent. Moreover, in toxicological terms the quality of the effluent without chlorination is better than the chlorinated one.

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Ambiental, Florianópolis, 2014. / Made available in DSpace on 2015-04-29T21:08:25Z (GMT). No. of bitstreams: 1 333005.pdf: 22437127 bytes, checksum: 7fff9aa514916f2595f87a73d886c766 (MD5) Previous issue date: 2014 / Diversos setores da indústria estão utilizando nanopartículas (NP)metálicas. Contudo, é difícil prever o comportamento dessas no meioambiente sem estudos toxicológicos. Dadas às característicasparticulares das NP, como reduzido tamanho, maior área superficial ecapacidade de aglomeração/dispersão, estas podem se translocarfacilmente pelos compartimentos ambientais potencializando os riscosao meio ambiente e ao homem. A NP de óxido de cromo III (NP Cr2O3)é aplicada na indústria principalmente como pigmentos, catalisadores ematerial refratário, contudo o seu efeito tóxico aos organismos vivos épouco conhecido. Assim, o objetivo deste estudo foi avaliar o efeito daNP Cr2O3 na população de algas unicelulares Chlamydomonasreinhardtii, bactéria luminescente marinha Aliivibrio fischeri,microscrustáceo Daphnia magna e investigar o efeito citotóxico, atravésdo ensaio de MTT e lipoperoxidação, sobre células Vero. As C.reinharditii foram expostas às NP Cr2O3 para avaliar os efeitos sobre aprodução de espécies reativas de oxigênio (ROS), atividade esterase,viabilidade celular e fotossistema II. Para o estudo com D. magna,foram realizados teste de toxicidade aguda e crônica. Foram feitos testesde inibição de luminescência com A. fischeri, para os tempos de 15 e 30minutos. As células Vero foram expostas às NP por 24 horas, paraobservação do efeito citotóxico e quantificação de MDA. Os testes comalgas mostraram, em 24 horas, um aumento significativo no nível deROS para toda a população exposta à NP Cr2O3 e CE50,24h de 1,57±0,53g L-1. D. magna mostrou-se sensível à NP Cr2O3, apresentando umaCE50,48h de 101,74 mg L-1. Foi observado efeito crônico sobre D. magnacom valor de CEO de 10 mg L-1 para reprodução e crescimento, e CEO50mg L-1 para o parâmetro longevidade. A bactéria A. fischeri semostrou menos sensível à NP apresentando valores de CE50,15min de769,17±19,69 mg L-1 e CE50,30min de 980,00±134,35 mg L-1. Osresultados obtidos nas avaliações toxicológicas com células Verodemonstraram que a NP Cr2O3 possui um potencial efeito citotóxico,pois reduz a viabilidade celular das células Vero (CE50,24h =0,97±0,56 g L-1). Os resultados demonstraram que a NP Cr2O3 possuipotencial para causar efeito de toxicidade aguda e crônica, bem comoalterações a nível celular em organismos de água doce e salgada.<br> / Abstract : Metallic nanoparticles (NPs) are being used in several industrial fields.However, the toxicologic studies default hinders the observation of thebehavior of these particles on the environment. The intrinsiccharacteristics of NPs such as: low size, larger surface area and capacityto agglomeration / dispersion, facilitate its displacement through ofenvironmental compartments potentiating the environment and humansrisks. Although Chromium (III) oxide nanoparticles (Cr2O3 NP) areapplied in industry mainly as pigments, catalysts and refractory materialforms, studies developed to evaluate its toxic effect on living organismsare scarce. Thus the present study has aimed to evaluate the toxic effectsof Cr2O3 NP on the unicellular algae population Chlamydomonasreinhardtii, the marine luminescent bacteria Aliivibrio fischeri, themicrocrustacean Daphnia magna and to investigate the cytotoxic effectby MTT and lipid peroxidation assay on Vero cells. C. reinhardtii wereexposed to Cr2O3 NP to evaluate its effects on reactive oxygen species(ROS) production, esterase activity, cell viability and photosystem II. D.magna were exposed to NPs suspensions to perform acute and chronictoxicity tests. A. fischeri was exposed to NPs suspensions at 15 and 30minutes to perform luminescence inhibition tests. Vero cells wereexposed to Cr2O3 NPs to a 24h period to observe the cytotoxic effectthrough the MTT assay and to MDA quantification. The results withalgae showed in 24 hours, an significant increase of ROS levels for theentire population exposed to Cr2O3 NPs and EC50,24h of 1.57±0.53 g L-1.The D. magna was sensitive to Cr2O3 NPs, at EC50,48h of 101.74 mg L-1.With respect to chronic toxicity, Cr2O3 NPs showed a statisticallysignificant effect (p < 0.05) on the growth and reproduction parameters(OEC = 10 mg L-1). In relationship to A. fischeri assay, the resultsshowed less sensitivity to NP demonstrating values of EC50,15min =769.17±19.69 mg L-1 and EC50,30min = 980.00±134.35 mg L-1. Theresults obtained of Vero cells showed that Cr2O3 NPs has the cytotoxiceffect potential because it reduces cell viability of Vero cells (CE50,24h =0.97±0.56 g L-1). The results showed that the Cr2O3 NPs have potentialto cause toxic effects (acute and chronic), as well as changes at thecellular level in fresh and salt water organisms.

Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Química, Florianópolis, 2016. / Made available in DSpace on 2017-03-21T04:11:42Z (GMT). No. of bitstreams: 1 344682.pdf: 2246781 bytes, checksum: 3002450683b92d04ea6979b0ba65a770 (MD5) Previous issue date: 2016 / O presente estudo propôs o emprego de um caulim proveniente de Juazeirinho, no Estado da Paraíba, como fonte de alumínio e silício para a produção de zeólita 4A a partir de reação hidrotérmica, onde o procedimento de síntese consistiu na ativação térmica do caulim, que foi submetido, em mulfla, a uma temperatura de 850°C por 2 horas, para tornar-se metacaulim; 3g deste metacaulim obtido foi adicionada a um recipiente de teflon/alumínio juntamente com 30mL de uma solução de NaOH 1,25 mols/L, e este sistema foi colocado em estufa, a 150°C, por 4 horas à pressão autógena, para ocorrer a reação hidrotérmica de formação de zeólita 4A. O material resultante foi centrifugado e lavado com água deionizada e até pH próximo a 7,0, e em seguida seco em estufa a 100°C por aproximadamente 15 horas. O caulim e a zeólita 4A produzida foram caracterizados por difração de raios X (DRX), espectroscopia de infravermelho (FTIR), fluorescência de raios X (FRX), calorimetria exploratória diferencial (DSC), termogravimetria (TG) e microscopia eletrônica de varredura (MEV). Os resultados de DRX mostraram que o caulim de Juazeirinho é constituído principalmente por caulinita, com baixos níveis de impurezas. Os dados dos ensaios de remoção determinados por ICP-OES sugerem que a zeólita 4A apresenta boa capacidade adsortiva atingindo eficiência de 82,7% para concentrações de 50 mg/L de As5+. Os resultados revelaram que o modelo de Langmuir é mais apropriado que o de Freundlich no ajuste dos dados experimentais. O máximo de remoção de íons arsenato (82,7%) ocorre em pH 5,0 empregando 1000 mg de zeólita 4A.O modelo cinético de pseudo-segunda ordem foi o que melhor descreveu os dados para a remoção de íons arsenato. No equilíbrio, a isoterma de Langmuir foi a que melhor representou os dados experimentais. Para o organismo D. magna foram observados efeitos tóxicos com um valor de LC50 (48h) de 2,02 mg/L para o arsenato. Durante os ensaios empregando zeólita 4A, foi observado um acúmulo de matéria no trato digestivo e na carapaça dos organismos, que é reversível com a remoção da zeólita do meio de ensaio.<br> / Abstract : The present study proposed the employment of a kaolin from Juazeirinho, in the State of Paraíba, such as aluminum and silicon for the production of 4A zeolite from hydrothermal reaction, where the synthesis procedure consisted of thermal kaolin activation, which was submitted, in mulfla, at 850°C for 2 hours, to become metakaolin; 3g of this obtained metakaolin was added to a teflon/aluminium container along with 30mL of a 1,25 mol/L NaOH solution, and this system was placed in an oven at 150°C for 4 hours at autogenous pressure, to occur 4A formation hydrothermal reaction. The resulting material was centrifuged and washed with deionized water until pH around 7.0, and then dryed in oven at 100°C for about 15 hours. Kaolin and produced 4A zeolite were characterized by X-ray diffraction (XRD), infrared spectroscopy (IR), X-ray fluorescence (XRF), differential scanning calorimetry (DSC), thermogravimetry (TG) and scanning electron microscopy (SEM). The XRD results showed that Juazeirinho?s kaolin is mainly composed of kaolinite with low impurity levels. Adsorption data determined by ICP-OES suggest that 4A zeolite has good adsorptive capacity, achieving the efficiency of 82.7% at 50 mg/L As5+ concentrations. The results revealed that the Langmuir model is more appropriate than Freundlich in the fit of the experimental data. The maximum removal of arsenate ions (82.7%) occurs at pH 5.0 employing 1000 mg of 4A zeolite. The pseudo-second order kinetic model was the model that best described the experimental data for the remotion of ions arsenate.For the equilibrium, the Langmuir isotherm was the one that best represented the experimental data. For D. magna organism, toxic effects were observed with LC50(48h) value of 2.02 mg/L of arsenate. During the tests employing 4A zeolite, it was observed its accumulation in the digestive tract and carapace of the organisms,which is reversible upon removal of 4A zeolite.

Aquatic toxicology has been identified as a valuable tool in the identification and management of chemical pollution in aquatic ecosystems. Standardised methodologies for acute aquatic bioassays have been adopted from international agencies. As a result of these standard methods, the use of laboratory cultured organisms for toxicity testing has been more popular than that of indigenous field-caught organisms. Included in these adopted methods are those for the cultured crustacean Daphnia pUlex. D.pulex is adapted to living in standing water and the suitability of this species to determine toxic effects for South African riverine environments, which are largely flowing, has been questioned. Thus this thesis is a case-study ofthe use of D.pulex and indigenous site-specific macroinvertebrates as toxicity test organisms for setting acute water quality guidelines to protect aquatic ecosystems. The study highlights site-specific problems such as reference sites and organism identification. The acute tolerance of selected indigenous invertebrates was compared to that of D. pulex, using both a single-substance reference toxicant (zinc) and selected whole efiluents. The significance of source population and culture age as a potential source of biological variability between D.pulex cultures was also investigated. D.pulex cultures have been initiated in South Africa from females collected from a number of different local populations; also it is assumed that no genetic change (due to mutation) occurs within a D.pulex culture over time. In order to establish if source population and culture age are a source of biological variability between D.pulex experiments, the acute tolerJuce to zinc of two different D.pulex populations and three different generations within a population were compared. Due to experimental variability results were inconclusive, and differences in tolerance as a result of population difference or culture age could not be determined with confidence. The acute tolerance of D.pulex to a single reference chemical (zinc) and selected whole efiluents was compared to that of selected indigenous invertebrates. Acute 48 h D.pulex zinc tolerance (LC50 range: 0.22 - 0.60 mg/l Zn) was found to be more sensitive than acute 96 h tolerances shown by mayfly species A.fconurus peringueyi (Heptageniidae) (LC50: 17.42 mg/l Zn), Euthrauluselegans (Leptophlebiidae) (LC50: 0.98 mg/IZn), Ba~tidae (LC50: 0.94mg/IZn) and shrimp, Caradina nilotica (Atyidae) (LC50: 3.17 mg/l Zn). This result suggests that guidelines for zinc set using D.pulex will protect the selected indigenous invertebrates. Selected whole eftluents were not acutely toxic to either D.pulex or selected indigenous invertebrates. These experiments were used as a case study for method development regarding the comparative use of D.pulex and indigenous invertebrates in acute whole eftluent toxicity testing. Finally, it is recommended that a suite of indigenous organisms (e.g. macroinvertebrates, fish and algae), as well as laboratory cultured D.pulex, be used in the initial setting of guidelines and that D.pulex be used for routine compliance monitoring. It is futher recommended that a suite of available monitoring methods, such as chemical and biomonitoring methodologies, be used in conjuction with toxicity testing in water quality management.