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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The toxicity of alkyl-chrysenes and benz[a]anthracenes to embryonic fish

Lin, HONGKANG 13 January 2014 (has links)
Alkylated polycyclic aromatic hydrocarbons (alkyl-PAHs) are major constituents of crude oil, and the 3-5 ringed alkyl-PAHs have been identified as the main components chronically toxic to fish. While chysene homologues have higher cytochrome P4501A (CYP1A) induction potencies than alkyl-phenanthrenes, there is little characterization of toxicity for 4-ringed alkyl PAHs. This study measured the chronic toxicity of chrysene, benz[α]anthracene, and some alkylated congeners to the embryos of Japanese medaka (Oryzias latipes) using the partition-controlled delivery method (PCD) of exposure. This exposure method relies on the partitioning of chemicals from polydimethylsiloxane (PDMS) films, loaded with various concentrations of test chemical, to embryo rearing solutions. The objectives of this thesis were: (1) to further characterize the PCD method with a series of 4-ringed PAHs; (2) to evaluate the effects of different chemical structures on the toxicity of test compounds; and (3) to extend structure toxicity relationships from alkyl-phenanthrenes. The PCD method generated a gradient of aqueous concentrations for test compounds, and these exposure concentrations were maintained constant for the 17-day period. Benz[α]anthracene showed higher toxicity than chrysene. Toxicity increased with the degree of alkylation on the ring structures, except that 2-methylbenz[α]anthracene was less toxic than the unsubstituted benz[α]anthracene. Substitutions at the middle region contributed to a higher toxicity than substitutions at the distal region. While actual mechanisms for these compounds to cause toxicity are unknown, the narcotic mode of action seems to be not involved due to the lack of mortality. Within the range of test concentrations, the chronic sublethal toxicity was limited by the low solubility of the test compounds. A structure toxicity relationship was illustrated by the regression between log EC50s and log Kow values. In addition to hydrophobicity represented by log Kow, structural dissimilarities between compounds and physical characteristics such as aqueous solubility limits should be taken into account in toxicity assessments with alkyl-PAHs. This research is the first toxicological assessment of alkyl-chrysenes and benz[α]anthracenes which is essential for a better understanding of structure toxicity relationships of alkyl-PAHs, and will contribute to more accurate ecological risk assessments of PAH contamination. / Thesis (Master, Biology) -- Queen's University, 2014-01-10 16:35:00.232
2

Modeling the Effects of Chronic Toxicity of Pharmaceutical Chemicals on the Life History Strategies of Ceriodaphnia Dubia: a Multigenerational Study

Lamichhane, Kiran 12 1900 (has links)
Trace quantities of pharmaceuticals (including carbamazepine and sertraline) are continuously discharged into the environment, which causes concern among scientists and regulators regarding their potential long-term impacts on aquatic ecosystems. These compounds and their metabolites are continuously interacting with the orgranisms in various life stages, and may differentially influence development of embryo, larvae, juvenile, and adult stages. To fully understand the potential ecological risks of two candidate pharmaceutical chemicals (carbamazepine (CBZ) and sertraline (SERT)) exposure on survival, growth and reproduction of Ceriodaphnia dubia in three sucessive generations under static renewal toxicity test, a multigenerational approach was taken. Results indicate that SERT exposure showed higher sensitivity to chronic exposure to C. dubia growth and reproduction than CBZ exposure. The lowest concentration to affect fecundity and growth was at 50 µg L-1 SERT in the first two generations. These parameters become more sensitive during the third generation where the LOEC was 4.8 µg L-1. The effective concentrations (EC50) for the number of offspring per female, offspring body size, and dry weight were 17.2, 21.2, and 26.2 µg SERT L-1, respectively. Endpoints measured in this study demonstrate that chronic exposure of C. dubia to SERT leads to effects that occur at concentrations an order of magnitude higher than predicted environmental concentrations indicating potential transgenerationals effects. Additionally, a process-based dynamic energy budget (DEB) model is implemented to predict the simulated effects of chronic toxicity of SERT and CBZ to C. dubia individual behavior at laboratory condition. The model‘s output indicates the ecotoxicological mode of action of SERT exposure, which acts on feeding or assimilation with an effect that rapidly saturates at higher concentrations. Offspring size decreases with the toxic effects on feeding, and offspring number is thus less affected than total investment in reproduction. Consequently, CBZ affects direclty in reproduction which are captured by DEBtox model as increased embryonic hazard and reproduction cost as well as growth and maintenance costs. Furthermore, stress factor linearly increased not only with increasing chemical concentrations but also with exposure time. The DEBtox model establishes a cumulative life history consequence of multigenerational exposure to CBZ and SERT. This approach provides a tool to which to understand the effect of chemical to the individual organism and predict the population level effects in ecological risk assessment of the emerging contaminants.
3

Identification of components in crude oil that are chronically toxic to the early life stages of fish

Khan, Colin Winston 02 January 2008 (has links)
The risk of crude oil exposure to the early life stages (ELS) of fish is difficult to assess, given the complexity of the chemical composition of different oils. The aromatic portion of crude oil contains polycyclic aromatic hydrocarbons (PAH), which are known to be toxic. In 2004, an “effects-driven” fractionation research program was initiated in an attempt to better identify toxic constituents of two unique crude oils, Alaskan North Slope Crude (ANSC; medium-heavy crude) and Scotia Light (SCOT; light crude). The ANSC contained much more PAH than SCOT. These oils induced cytochrome P4501A1 (CYP1A) enzymes in juvenile rainbow trout (Oncorhynchus mykiss) and caused blue-sac disease (BSD) and mortality in larval Japanese medaka (Oryzias latipes). Four unique fractions (F1-F4) were produced from both oils via low temperature vacuum distillation. The F3 contained an array of unsubstituted and alkyl-PAH, and was responsible for most of the CYP1A induction and chronic toxicity associated with whole oil. Cold acetone extraction (CAE) of F3 produced 2 new sub-fractions (F3-1 and F3-2). The F3-1 was rich in alkyl-PAH, was a potent CYP1A inducer, and was chronically toxic to ELS of fish. The F3-1 was further separated into five more sub-fractions via normal phase HPLC (F3-1-1 – F3-1-5). Neither F3-1-1 nor F3-1-2 induced CYP1A or produced BSD, but F3-1-2 was lethal. The F3-1-3, 4, and 5 were all potent CYP1A inducers and were all chronically toxic. Induction of CYP1A proved to be an effective tool for tracing potentially toxic PAH throughout fractionation (Chapter 2), and sub-fractions rich in alkyl-PAH caused the most BSD and mortality (Chapter 3). Alkyl-homologues of phenanthrene, fluorene, naphthobenzothiophene (NBT), pyrene, and chrysene are perhaps the most toxic of the known constituents present in crude oil. The ANSC sub-fractions were more toxic than the SCOT ones, indicating that heavier crude oils with a higher proportion of intermediate-sized alkyl-PAH may be more toxic than lighter crude oils that are comprised of fewer of these compounds. / Thesis (Master, Biology) -- Queen's University, 2007-12-20 13:18:50.794 / This research was accomplished with funding assistance from the Nationmal Oceanic and Atmospheric Administration (NOAA), Petroleum Research Atlantic Canada (PRAC), Environment Canada, and the Department of Fisheries and Oceans.
4

The Toxicity of Ammonia to the Summer Flounder (Paralychtus Dentatus), Atlantic Silverside (Menidia Menidia), and Quahog Clam (Mercenaria Mercenaria)

Starbuck, Steven M., Jr. 02 October 1998 (has links)
The toxicity of ammonia has become an issue in recent years, especially in the Chesapeake Bay watershed. Currently, the EPA has set a chronic criterion of 0.035 mg/L (unionized ammonia). The chronic criterion is a four-day average concentration that cannot be exceeded more than once every three years. However, a lack of data exists on the toxicity of ammonia to saltwater organisms. Prior to this research, the chronic criterion was based on two saltwater and four freshwater organisms. This research was conducted to add additional data so more appropriate criteria may be set. Two saltwater fish, the Summer Flounder (Paralichthys dentatus), and the Atlantic Silverside (Menidia menidia) and one invertebrate, the Quahog Clam (Mercenaria mercenaria) were tested for acute toxicity to ammonia. The acute tests performed on the Summer Flounder (2 months old) were 48 and 96-hour tests performed in both synthetic seawater and natural seawater. Seven-day chronic tests were also performed on the Summer Flounder using synthetic seawater. Both 48 and 96-hour acute tests were performed on the Atlantic Silverside (10-14 days old.) using natural seawater. Both 48 and 96-hour acute tests were performed on the Quahog Clam (5mm shell height) using synthetic seawater. The 48-hour LC50s for the Summer Flounder in synthetic and natural seawater were 1.22 mg/L and 1.09 mg/L, respectively. The 96-hour LC50s for the Summer Flounder in synthetic and natural seawater were 1.07 mg/L and 0.889 mg/L, respectively. The 7-day chronic NOEC was 1.37 mg/L. The 48 and 96-hour LC50s for Atlantic Silverside in natural seawater were 1.52 mg/L and 1.18 mg/L, respectively. The 48 and 96-hour LC50s for Quahog Clam in synthetic seawater were 216 mg/L and 36.6 mg/L, respectively. The acute-chronic ratio for the Summer Flounder was 2.27. The refined chronic criterion was 0.081 mg/L based on this research and the research of others. Summer Flounder were more sensitive to ammonia in natural seawater than synthetic seawater. However, Atlantic Silverside showed no difference in sensitivity. / Master of Science
5

Towards new computational tools for predicting toxicity

Chavan, Swapnil January 2016 (has links)
The toxicological screening of the numerous chemicals that we are exposed to requires significant cost and the use of animals. Accordingly, more efficient methods for the evaluation of toxicity are required to reduce cost and the number of animals used. Computational strategies have the potential to reduce both the cost and the use of animal testing in toxicity screening. The ultimate goal of this thesis is to develop computational models for the prediction of toxicological endpoints that can serve as an alternative to animal testing. In Paper I, an attempt was made to construct a global quantitative structure-activity relationship (QSAR)model for the acute toxicity endpoint (LD50 values) using the Munro database that represents a broad chemical landscape. Such a model could be used for acute toxicity screening of chemicals of diverse structures. Paper II focuses on the use of acute toxicity data to support the prediction of chronic toxicity. The results of this study suggest that for related chemicals having acute toxicities within a similar range, their lowest observed effect levels (LOELs) can be used in read-across strategies to fill gaps in chronic toxicity data. In Paper III a k-nearest neighbor (k-NN) classification model was developed to predict human ether-a-go-go related gene (hERG)-derived toxicity. The results suggest that the model has potential for use in identifying compounds with hERG-liabilities, e.g. in drug development.
6

Perfil epidemiológico dos trabalhadores avaliados no programa de atenção à saúde de populações expostas a agrotóxicos da Unicamp entre 2003 e 2012 / Epidemiological profile of employees evaluated in the health attention program to population exposed to pesticides of Unicamp from 2003 to 2012

Viciana, Ricardo Sallai, 1983- 02 September 2015 (has links)
Orientador: Angelo Zanaga Trape / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-26T23:15:54Z (GMT). No. of bitstreams: 1 Viciana_RicardoSallai_M.pdf: 1822886 bytes, checksum: ea2731dfa20dd83833222149436cc195 (MD5) Previous issue date: 2015 / Resumo: A preocupação com a saúde dos trabalhadores rurais expostos a agrotóxicos deve aumentar na mesma medida que se aumenta o consumo de agrotóxicos no Brasil. Esta população cada vez mais crescente possui características próprias e necessita de uma atenção à saúde especializada. A Unicamp realiza desde 1982 um Programa de Investigação das Intoxicações por Agrotóxicos. Com o passar dos anos este programa foi se aperfeiçoando e se tornou um Programa de Atenção à Saúde de Populações Expostas à Agrotóxicos incorporado à grade curricular desta Instituição. Trata-se de um estudo descritivo e retrospectivo a partir de dados secundários do Programa entre os anos de 2003 e 2012. No período foram avaliados 3797 trabalhadores rurais através da aplicação de um questionário semi-estruturado, sendo possível traçar um perfil epidemiológico desta população. 79,64% dos trabalhadores eram homens, a idade média foi de 40,97 anos, 70,56% dos trabalhadores alcançaram algum ano do segundo grau e 85,7% moravam na zona rural. A maioria dos entrevistados se declararam agricultores (78,72%) e mantinham contato direto com agrotóxicos (79,37%). O tempo médio de exposição aos agrotóxicos foi de 16,63 anos, sendo que 40,37% dos trabalhadores descreveram uso contínuo por 12 meses no ano. Os produtos mais usados foram os inseticidas organofosforados e piretróides, herbicida glifosato e fungicidas do grupo do Mancozeb. As principais culturas foram de laranja, flores, batata e hortaliças. Dos trabalhadores, 13,40% relataram episódios de intoxicação, sendo que 5,16% foram internados pela intoxicação. A via de exposição cutânea foi a mais relevante em 78,43% das vezes e o uso de roupa impermeável adequada ocorreu em apenas 36,58% dos relatos. Os sintomas mais descritos foram cefaleia (26,23%), queimação de estômago (19,70%), irritação ocular (18,83%), azia (17,11%), hipoacusia (15,32%), agitação/irritabilidade (14,72%) e irritação nasal (14,51%). De todos os 3797 trabalhadores avaliados, 469 foram identificados como casos suspeitos de intoxicação (12,35%) e foram encaminhados para o Ambulatório de Toxicologia da Unicamp para definição diagnóstica / Abstract: Concern for the health of agricultural workers exposed to pesticides should increase to the same extent that it increases the consumption of pesticides in Brazil. This ever-increasing population has its own characteristics and needs a health care specialist. Unicamp held since 1982 a program of Research of Poisoning by Pesticides. Over the years this program was improved and became a Health Care Program of Populations Exposed to Pesticides and was incorporated into the curriculum of this institution. Through a retrospective descriptive study based on secondary data was possible to consolidate data between the years 2003 and 2012. In the period 3797 rural workers were evaluated through a semi-directed questionnaire, it is possible to outline an epidemiological profile of this population. 79.64% of the workers were men, the average age was 40.97 years, the school found that 70.56% of the workers studied high school and 85.7% lived in rural areas. Most said they were farmers (78.72%) and had direct contact with pesticides (79.37%). The mean duration of exposure to pesticides was 16.63 years, and 40.37% of workers reported continuous use for 12 months in the year. The most commonly used products were the organophosphate and pyrethroid insecticides, herbicide glyphosate and fungicides Mancozeb. The main crops were orange, flowers, potatoes and vegetables. 13.40% reported episodes of intoxication, and 5.16% were hospitalized for poisoning. Dermal exposure pathway was the most relevant in 78.43% of cases and the use of appropriate waterproof clothing occurred in only 36.58% of cases. Most described symptoms were headache (26.23%), stomach burning (19.70%), eye irritation (18.83%), heartburn (17.11%), hearing loss (15.32%), agitation/irritability (14.72%) and nasal irritation (14.51%). Of all 3797 workers evaluated, 469 were identified as suspected cases of poisoning (12.35%) and were referred to the Unicamp Toxicology Clinic for diagnostic definition / Mestrado / Epidemiologia / Mestre em Saude Coletiva
7

Long-Term Sub-Lethal Effects of Low Concentration Commercial Herbicide (Glyphosate/Pelargonic Acid) Formulation in Bryophyllum Pinnatum

Pokhrel, Lok R., Karsai, Istvan 05 December 2015 (has links)
Potential long-term (~7months) sub-lethal impacts of soil-applied low levels of Roundup herbicide formulation were investigated in a greenhouse environment using the vegetative clones of succulent non-crop plant model, Bryophyllum pinnatum (Lam.) Oken. An eleven day LC50 (concentration that killed 50% of the plants) was found to be 6.25% (~1.25mg glyphosate/mL and 1.25mg pelargonic acid/mL combined), and complete mortality occurred at 12.5%, of the field application rate (i.e., ~20mg glyphosate/mL and 20mg pelargonic acid/mL as active ingredients). While sub-lethal Roundup (1-5%) exposures led to hormesis-characterized by a significant increase in biomass and vegetative reproduction, higher concentrations (≥6.25%) were toxic. A significant interaction between Roundup concentrations and leaf biomass was found to influence the F1 plantlets' biomass. Biomass asymmetry generally increased with increasing Roundup concentrations, indicating that plants were more stressed at higher Roundup treatments but within the low-dose regime (≤5% of the as-supplied formulation). While leaf apex region demonstrated higher reproduction with lower biomass increase, leaf basal area showed lower reproduction with greater biomass increase, in plantlets. The results suggest long-term exposures to drifted low levels of Roundup in soil may promote biomass and reproduction in B. pinnatum.
8

Assessment of the single and mixture ecotoxicity of pharmaceuticals of environmental concern using aquatic test organisms / Avaliação da ecotoxicidade individual e das misturas de fármacos de preocupação ambiental usando organismos-teste aquáticos

Godoy, Aline Andrade 05 July 2019 (has links)
Pharmaceuticals are contaminants of emerging concern which have been a target of increasing attention by the scientific community. Pharmaceuticals presenting high consumption, incomplete metabolism and incomplete removal at wastewater treatment plants have been frequently detected in aquatic ecosystems worldwide. This is the case of the pharmaceuticals metformin (MET), bisoprolol (BIS), sotalol (SOT) and ranitidine (RAN). However, ecotoxicity data for these contaminants are scarce, especially regarding behavior effects and chronic toxicity. In addition, the knowledge regarding the joint toxicity of these pharmaceuticals on non-target organisms is still incipient, which makes their environment risk assessment uncertain. This study aimed to fill these knowledge gaps for these four pharmaceuticals, by carrying out toxicity tests using five test organisms from three trophic levels. Different endpoints were assessed in tests with Raphidocelis subcapitata (algae), Lemna minor (macrophyte), Daphnia similis (crustacean), Hydra attenuate (cnidarian) and Danio rerio (fish). The binary and quaternary mixture acute toxicity for these pharmaceuticals were assessed on D. similis and D. rerio embryo tests, respectively. This study also aimed to evaluate the predictive accuracy of the Concentration addition (CA) and the Independent action (IA) classic models. In addition, the nature of the possible toxicological interactions between the pharmaceuticals in binary mixtures were also evaluated, using the Combination Index-isobologram (CI) method. The modelling of the concentration-response curves and the associated statistical analyses were performed using the automated spreadsheet ToxCalcMix v.1.0 and the software OriginPro 2015. The software CompuSyn was used for performing the mixture analyses with the CI method. The experimental planning of the binary mixture tests was performed using the fractioned factorial design, in order to cover several possible ratio and level-dependent effects with a reduced number of test organisms. The results obtained in this study are shown in four articles. In article 1, we provided a critical review and discussed the misunderstandings, deficiencies and data gaps on the ecotoxicity data of pharmaceuticals and personal care products mixtures published in the literature. In the following articles, the results obtained from the single and mixture toxicity tests performed in this study were presented and discussed. The pharmaceuticals MET (article 2) and BIS (article 3) were classified as hazardous to the aquatic environment, in the acute toxicity category. However, an ecological risk is not expected for the pelagic freshwater species exposed to these two pharmaceuticals, based on the chronic data obtained. The results obtained from the mixture toxicity tests (article 4) showed that most of the observed toxicity effects from the binary mixtures were in the zone between the predicted effects by the CA and IA models. The CI model showed to be an useful tool to describe the possible toxicological interactions occurring between the pharmaceuticals in joint action. Even statistically significant non-effect concentrations of the pharmaceuticals added up to induce significant adverse effects in mixtures (something from nothing). It was concluded that ecological risk assessment based on single toxic effects can underestimate the real impact of environmental contaminants on aquatic ecosystems. / A contaminação ambiental por fármacos tem sido alvo de crescente preocupação pela comunidade científica. Fármacos de elevado consumo, incompleto metabolismo e remoção incompleta em estações de tratamento de esgoto, como é o caso da metformina (MET), bisoprolol (BIS), sotalol (SOT) e ranitidina (RAN), têm sido frequentemente detectados em matrizes aquáticas do mundo todo. Apesar disso, dados ecotoxicológicos consistentes para esses contaminantes são escassos, principalmente com relação a efeitos comportamentais e oriundos de estudos crônicos. Além disso, o entendimento dos efeitos de suas ações combinadas em organismos não-alvo é ainda incipiente, o que gera incertezas na avaliação dos seus riscos ambientais. Esta pesquisa teve por objetivo preencher essas lacunas de conhecimentos para esses quatro fármacos, por meio da realização de testes com cinco diferentes organismos-teste de três diferentes níveis tróficos. Foram analisados diferentes parâmetros avaliativos em testes com os organismos aquáticos Raphidocelis subcapitata (alga), Lemna minor (macrófita), Daphnia similis (crustáceo), Hydra attenuata (cnidário) e Danio rerio (peixe). As toxicidades agudas das misturas binárias e quaternárias desses quatro fármacos também foram avaliadas em testes com D. similis e embriões de D. rerio, respectivamente. Este trabalho também teve por objetivo avaliar a acurácia preditiva dos modelos de adição de concentração (CA) e ação independente (IA) e analisar a natureza das possíveis interações toxicológicas entre os fármacos, em misturas binárias, usando o modelo do Índice de Combinação (CI). A modelagem das relações concentração-resposta e as análises estatísticas associadas foram realizadas empregando-se a planilha automatizada ToxCalcMix versão 1.0 e o software OriginPro 2015. O software CompuSyn foi utilizado para as análises envolvendo o CI. O planejamento experimental dos testes de misturas binárias foi realizado por meio do design fatorial fracionado, a fim de cobrir diversas possíveis interações em várias proporções e níveis de efeitos, com a redução do número de organismos-teste. Os resultados desta pesquisa estão apresentados em quatro artigos. No artigo 1, realizou-se uma revisão crítica com relação às lacunas de conhecimentos e deficiências identificadas a partir da análise da literatura sobre a ecotoxicologia de misturas de fármacos e de produtos de higiene pessoal. Nos artigos seguintes, foram apresentados e discutidos os resultados oriundos dos testes com os quatro fármacos avaliados neste estudo. Os fármacos MET (artigo 2) e BIS (artigo 3) foram classificados como perigosos para o ambiente aquático, na categoria de toxicidade aguda. Contudo, um risco ecológico não é esperado para as espécies pelágicas de água doce expostas a esses dois fármacos, com base nos dados de toxicidade crônica obtidos. Os resultados dos testes de misturas (artigo 4) permitiram concluir que a maior parte dos efeitos observados das misturas binárias estiveram na zona entre os efeitos preditos pelos modelos clássicos de CA e IA. O modelo do CI mostrou-se uma ferramenta útil para descrever a natureza das possíveis interações toxicológicas que ocorrem entre os fármacos em ações combinadas. Mesmo concentrações de nenhum efeito estatisticamente significativo dos fármacos causaram efeitos adversos significativos quando em misturas (something from nothing). Concluiu-se que avaliações de risco ecológicas baseadas em efeitos tóxicos individuais de contaminantes ambientais podem subestimar o real impacto desses compostos em ecossistemas aquáticos.
9

Efeito do hormônio sintético 17α-etinilestradiol no invertebrado aquático Daphnia magna (Crustacea, Cladocera) / The effect of the synthetic hormone 17α-ethinyl estradiol on the aquatic invertebrate Daphnia magna (Crustacea, Cladocera)

Miguel, Mariana 12 February 2016 (has links)
Muitas substâncias descartadas no meio ambiente não são totalmente degradadas, podendo assim persistir no ambiente. Diversos compostos são continuamente introduzidos no ambiente podendo afetar a biota e inclusive o homem. Os fármacos são alguns desses compostos que depois de descartados podem chegar nos corpos de águas naturais, e dentre eles merecem especial atenção os hormônios sintéticos utilizados em larga escala por mulheres em todo o mundo, na forma de contraceptivos orais. O hormônio sintético 17α-etinilestradiol é um micropoluente no ambiente aquático, que pode causar distúrbios na reprodução de diversos organismos atuando como um desregulador endócrino. O presente estudo teve como objetivo principal analisar o efeito do hormônio sintético 17α-etinilestradiol sobre o cladócero Daphnia magna, por meio de testes ecotoxicológicos. Testes de toxicidade crônica foram realizados em duas gerações consecutivas deste microcrustáceo (F0 e F1). Para os testes utilizaram-se neonatas com menos de 24 horas de idade, 6 concentrações do hormônio e dois controles. Foram estabelecidas 10 réplicas com 1 indivíduo por réplica. O ensaio foi realizado em incubadora com temperatura de 25 ± 1°C e fotoperíodo de 12h claro:12h escuro, com duração de 11 (F0) e 13 dias (F1), com término coincidindo com o nascimento das neonatas da terceira ninhada no controle. Os resultados evidenciaram que a exposição ao hormônio diminuiu a fecundidade de Daphnia magna nas quatro maiores concentrações de etinilestradiol na F0 e na concentração de 1000 μg L-1 da F1, revelando maior resistência ao contaminante na segunda geração. Na maior concentração do composto, o tempo para a produção das duas primeiras ninhadas foi maior na geração F1, quando comparada ao controle. Na concentração de 250 μg L-1 verificou-se a ocorrência de um indivíduo intersexo, apresentando tanto características de macho como de fêmea. Os resultados deste estudo evidenciaram que o 17α-etinilestradiol afeta a reprodução de Daphnia magna, e que também pode afetar a reprodução de diferentes invertebrados aquáticos, o que, a longo prazo pode causar danos às populações e comunidades aquáticas, diminuindo as populações e podendo até extingui-las eventualmente. / Many substances are discarded in the environment and not completely degraded, thus persisting in the environment. Some of these are continuously introduced in the environment, affecting the biota, including man. Pharmaceutical drugs are some of these compounds that after discarded can occur in natural water bodies and among them the synthetic hormones deserve special attention for being used in large scale by women world widely, as oral contraceptives. The synthetic hormone 17α-ethinyl estradiol is therefore a micropoluent in the aquatic environment, i. e. found in low concentrations that can cause deleterious effects in the reproduction of many organisms, acting as an endocrine disruptor. The present study had as main objective to analyze the effect of the synthetic estrogen 17α-ethinyl estradiol on the cladoceran Daphnia magna, by carrying out ecotoxicological tests. Chronic toxicity tests were performed on two consecutive generations of this microcrustacean (F0 and F1). In order to perform the tests, neonates aged less than 24 hours, 6 hormones concentrations and two types of controls were used. Ten replicates were established with one individual each. The test was performed in a growth chamber at the constant temperature of 25 ± 1°C and 12 h light:12 h dark photoperiod, had the duration of 11 and 13 days for the F1 and F0 generations, respectively, coinciding with the birth of the third brood in the control. The results evidenced that the exposition to the hormone decreased D. magna fecundity in the four highest of ethinyl estradiol in F0, and in the concentration 1000 μg L-1 for the F1, indicating resistance increase in the second generation. In the highest concentration of this compound the time for the production of the first two broods were higher in the F1 generation as compared with the controls. In the hormone concentration of 250 μg L-1 the occurrence of an intersex individual was verified, simultaneously presenting characteristics of male and female. The results of this study evidenced the 17α-ethinyl estradiol affect the reproduction of Daphnia magna, and can affect the reproduction of other aquatic invertebrates that at long term can cause damages to aquatic populations and communities by diminishing populations and eventually leading them to the extinction.
10

Biomarcadores enzimáticos e testes ecotoxicológicos na avaliação da toxicidade de fármacos em invertebrados aquáticos / Enzymatic biomarkers and ecotoxicological tests to evaluate the toxicity of pharmaceutical drugs to aquatic invertebrates

Oliveira, Laira Lúcia Damasceno de 24 October 2014 (has links)
Dentre os compostos xenobióticos que podem vir a promover efeitos prejudiciais em ecossistemas aquáticos, os fármacos recebem atualmente maior destaque devido à capacidade de persistirem nestes ambientes e também pela escassez de informações de seus efeitos aos diferentes componentes da biota aquática. Dada a presença dessas substâncias, magnitude das concentrações (ng L-1 a μg L-1), e carência de informações sobre seus riscos aos organismos aquáticos nas águas doce no país, o presente estudo estabeleceu como objetivos: i) avaliar a presença dos compostos farmacológicos: diclofenaco de sódio (anti-inflamatório), paracetamol (analgésico) e propranolol (β- bloqueador) nas amostras de água em diferentes pontos selecionados no Reservatório de Guarapiranga-SP; ii) estabelecer o grau de toxicidade aguda destes compostos farmacológicos notoriamente encontrados nas amostras naturais sobre diferentes grupos de organismos aquáticos, como: Ceriodaphnia silvestrii, Daphnia magna, Hydra viridissima e Dugesia tigrina; iii) Avaliar a toxicidade crônica dos fármacos estudados, com a inclusão do antipsicótico clorpromazina, aos cladóceros Ceriodaphnia silvestrii e Daphnia magna; iv) Analisar os efeitos sobre biomarcadores de neurotransmissão, como colinesterases solúveis (ChE); e de estresse e dano oxidativo, tais como catalase (CAT), glutationa-S-transferases (GSTs) e glutationa-peroxidase total e selêniodependente (GPx total e Se-GPx) na espécie D. magna. Os resultados mostraram que as concentrações dos fármacos variaram de 6,04 ng L-1 para o diclofenaco sódico (estação Santa Rita) a 531,4 ng L-1 para o paracetamol (estação Guavirutuba), durante os períodos analisados. Em relação aos resultados obtidos das exposições agudas observou-se uma variabilidade considerável na toxicidade dos dois compostos farmacêuticos estudados, com valores de CE50 e CL50 variando de 0,55 a 123,3 mg L-1, respectivamente, sendo que a espécie D. tigrina foi mais sensível ao fármaco diclofenaco sódico, e ao mesmo tempo apresentou uma maior tolerância ao propranolol. Os dados dos testes de toxicidade crônica mostraram a ocorrência de efeitos adversos na reprodução, mas também efeitos estimulantes para as espécies de Cladocera estudadas. O fármaco propranolol causou um aumento significativo na fecundidade e no parâmetro taxa de crescimento populacional ocorreu um aumento significativo na menor concentração testada para C. silvestrii. Para a espécie D. magna, a clorpromazina e o propranolol causaram uma diminuição significativa na fecundidade e na variável taxa de crescimento populacional. A exposição aos fármacos paracetamol e diclofenaco sódico causou uma inibição na atividade de ChE, Se-GPx e GPx total em D. magna, sendo que o propranolol foi responsável por uma redução significativa nas atividades das duas últimas enzimas mencionadas, e também por um ligeiro aumento na atividade de GSTs. Além disso, somente a atividade da CAT foi alterada de forma significativa na exposição à clorpromazina. Diante do exposto, conclui-se que os fármacos estudados causaram toxicidade aos organismos aquáticos avaliados neste estudo, e que há necessidade de maiores estudos visando integrar a avaliação de risco de fármacos e a proteção dos organismos não-alvo, da ameaça representada pela presença destes produtos no ambiente. / Among the xenobiotic compounds that may cause deleterious effects on aquatic ecosystems, the drugs currently receive greater prominence due to the ability to persist in these environments and also by the lack of information of their effects on different components of the aquatic biota. Given the presence of these, the magnitude of concentrations (ng L-1 to mg L-1), and lack of information about their risks for aquatic organisms in fresh waters in the country, this study has established the following objectives: i) to evaluate the presence of the pharmacutical compounds: diclofenac sodium (anti-inflammatory), paracetamol (analgesic) and propranolol (β-blocker) in water samples at different selected sites in Guarapiranga Reservoir -SP; ii) establish the degree of acute toxicity of these pharmacological compounds notoriously found in natural samples on different groups of aquatic organisms, such as: Ceriodaphnia silvestrii, Daphnia magna, Hydra viridissima and Dugesia tigrina; iii) to assess the chronic toxicity of the drugs studied, with the inclusion of antipsychotic chlorpromazine to cladocerans Ceriodaphnia silvestrii and Daphnia magna; iv) analyze the effects on biomarkers of neurotransmission, such as soluble cholinesterase (ChE); and oxidative stress defense, such as catalase (CAT), glutathione S-transferases (GSTs) and total and selenium-dependent glutathione-peroxidase (total GPx; Se-GPx) in the species D. magna. The results showed that the concentrations of the drugs ranged from 6.04 ng L-1 for diclofenac (Santa Rita station) to 531.4 ng L-1 for paracetamol (Guavirutuba station) during the periods analyzed. Regarding the results obtained from acute exposures a considerable variability in toxicity of the two pharmaceutical compounds studied was observed, and the EC50 and LC50 values ranged from 0.55 to 123.3 mg L-1, and the species D. tigrina was more sensitive to the drug diclofenac, and at the same time had a higher tolerance to propranolol. The data from chronic toxicity tests showed the occurrence of adverse effects on reproduction, but also stimulating effects to the species of Cladocera studied. The drug propranolol caused a significant increase in fertility and regarding the rate of population growth parameter there was a significant increase in the lowest concentration tested for C. silvestrii. For the species D. magna, chlorpromazine and propranolol caused a significant decrease in fertility and the rate of population increase parameter. Exposure to the drugs paracetamol and diclofenac caused an overall inhibition in the activity of ChE, Se-GPx and total GPx in D. magna, and propranolol was responsible for a significant reduction in the activities of the last two enzymes mentioned, and also for a slight increase in the activity of GSTs. Furthermore, only CAT activity was significantly altered in the exposure to chlorpromazine. Given the above, it is concluded that the studied drugs caused toxicity to the aquatic organisms evaluated in this study, which suggests that further studies are necessary to integrate risk assessment of drugs to the protection of non-target organisms of the threat posed by the presence of these products in the environment.

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