A study of macroinvertebrate colonization and assemblages, including secondary productivity of the familiar bluet damselfly or Enallagma civile Hagen (Odonata: Coenagrionidae), associated with the aquatic macrophytes Heteranthera dubia (Jacq.) MacMill. (water stargrass) and Potamogeton nodosus Poir. (American pondweed) was conducted at the Dallas Floodway Extension Trinity River Project (DFE) Lower Chain of Wetlands (LCOW), Dallas, TX, from September 2010 through November 2011. Macroinvertebrate abundance, taxa richness, Simpson's index of diversity, and Simpson's evenness from the two macrophytes and from three different wetland cells of varying construction completion dates, water sources, and native aquatic vegetation establishment were analyzed along with basic water quality metrics (temperature °C, pH, dissolved oxygen mg/L, and conductivity µs/cm). E. civile nymphs were separated into five developmental classes for secondary productivity estimations between macrophytes and wetland cell types. Mean annual secondary productivity in the DFE LCOW among two macrophytes of E. civile was 1392.90 ash-free dry weight mg/m²/yr, standing stock biomass was 136.77 AFDW mg/m2/yr, cohort production / biomass (P/B) ratio was calculated to be 4.30 / yr and the annual production / biomass (P/B) ratio was 10.18 /yr.

Made available in DSpace on 2014-06-11T19:30:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-07-29Bitstream added on 2014-06-13T20:21:11Z : No. of bitstreams: 1 franca_jg_dr_jabo.pdf: 2251025 bytes, checksum: 4391181f6db61217e2ad4bea2e7f55fd (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / O objetivo deste estudo foi avaliar o potencial tóxico do permanganato de potássio (KMnO4) através da avaliação da toxicidade aguda (CL50;96 h) e crônica para a tilápia, Oreochromis niloticus e a ecotoxicidade desse composto através de ensaios com o microcrustáceo Ceriodaphnia dubia e com a microalga Pseudokirchneriella subcapitata. Para o teste de toxicidade aguda foram utilizados alevinos de tilápia (0,52 + 0,10g e 3,35 + 0,36 cm), expostos a seguintes concentrações: 0; 0,5; 1,0; 2,0; 4,0 e 6,0 mg.L-1 KMnO4. Os efeitos subletais do KMnO4 foram avaliados pelo do teste de toxicidade crônica, com um grupo controle e duas concentraçõesteste, utilizadas na aqüicultura para o manejo e controle de doenças (1,0 e 4,0 mg.L-1 KMnO4). Para este teste foram utilizadas tilápias (40 g) jovens, expostas por 30 dias, com amostragem de 10 indivíduos por tratamento, nos intervalos de 0, 7, 15 e 30 dias. Os biomarcadores avaliados no presente estudo foram: análises hematológicas, da atividade fagocítica, determinações da concentração de GSH, da atividade enzimática da GST, catalase e peroxidação lipídica e genótoxicas. No teste de toxicidade aguda, o baixo valor de CL50;96h (1,81 mg.L-1), sugere que esta espécie de peixe, nesta fase de desenvolvimento, apresenta grande sensibilidade ao composto. No teste de toxicidade crônica, os peixes expostos na concentração de 1 mg.L-1 de KMnO4 não apresentaram variações significativas nos parâmetros sanguíneos analisados quando comparados ao grupo controle. Na concentração de 4 mg.L-1, as alterações no quadro hematológico indicaram processo de hemólise e redução da atividade fagocítica em consequência da ação oxidante do KMnO4. Nas concentrações de 1 e 4 mg.L-1 KMnO4 houve redução significativa da capacidade fagocítica de macrófagos. Na análise bioquímica, somente a enzima GSH apresentou aumento significativo... / This study aimed know the toxic potential of the potassium permanganate (KMnO4) through the evaluation of the acute (LC50;96h) and cronic toxicity to tilapia, Oreochromis niloticus and the ecotoxicity of this compound through the assays with the microcrustacean Ceriodaphnia dubia and with microalgae Pseudokirchneriella subcapitata. For the acute toxicity test were used tilapia fingerlings (0.52 + 0.10g and 3.35 + 0.36 cm), exposed to concentrations: 0; 0.5; 1.0; 2.0; 4.0 and 6.0 mg.L-1 KMnO4. The sublethal effects of the KMnO4 were evaluated through cronic toxicity test, with a control group and two test concentrations, used in the aquaculture to management and control fishes diseases (1.0 and 4.0 mg.L-1 KMnO4). To this experiment were used with juvenile tilapia (40 g), exposed for 30 days, with samples of 10 individuals from each treatment at intervals of 0, 7, 15 and 30- days. The biomarkers evaluated in this present study were: hematological analysis, phagocytic activity, determination of GSH concentration, of enzymatic activity of GST, catalase, lipid peroxidation and genotoxities. In the acute toxicity test, the low value of LC50;96h (1.81 mg.L- 1), suggests that this species of fish, in this phase of development, it presents the great sensitivity to the KMnO4. In the cronic toxicity test, the fishes exposed in the concentrations of 1 mg.L-1 de KMnO4 did not present significant variations in the analyzed sanguineous parameters when compared with the control group. In concentration of 4 mg.L-1 the hematological alterations indicated process of hemolysis and immunosuppression in consequence of the oxidant action of KMnO4. In the immunologicals analysis, the concentrations of 1 and 4 mg.L-1 KMnO4 had significant reduction of the fagocitic capacity of the fishes suggesting suppression of the immune system. In the analysis biochemical, only the enzyme GSH presented significant increase... (Complete abstract click electronic access below)

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-04-17T23:51:07Z No. of bitstreams: 1 WanessaKalineDeAraujoMoura_TESE.pdf: 2835389 bytes, checksum: 2e690065461ca562c7c35cca77b810e5 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-04-21T00:20:21Z (GMT) No. of bitstreams: 1 WanessaKalineDeAraujoMoura_TESE.pdf: 2835389 bytes, checksum: 2e690065461ca562c7c35cca77b810e5 (MD5) / Made available in DSpace on 2017-04-21T00:20:21Z (GMT). No. of bitstreams: 1 WanessaKalineDeAraujoMoura_TESE.pdf: 2835389 bytes, checksum: 2e690065461ca562c7c35cca77b810e5 (MD5) Previous issue date: 2016-01-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / O trabalho de pesquisa objeto deste projeto foi desenvolvido na regi?o do baixo curso do rio Doce no munic?pio de Natal, nos bairros de Lagoa Azul, Paju?ara e Redinha, ao longo do Rio Doce, limite com o munic?pio de Extremoz, Rio Grande do Norte. A regi?o da plan?cie fluvial do Rio Doce localiza-se em Zona de Prote??o Ambiental (ZPA-9). Esta ZPA ? uma das que ainda n?o est?o regulamentadas e nela s?o observados diversos problemas ambientais decorrentes do uso e ocupa??o do solo, caracterizando um flagrante desrespeito ? legisla??o ambiental e cuja prote??o ? dificultada devido ? inexist?ncia de mecanismos legais espec?ficos. Este trabalho tem por objetivos implantar e estabelecer a manuten??o do cultivo da esp?cie Hyalella azteca (Crustacea, Amphipoda) no Laborat?rio de Ecotoxicologia - ECOTOX (UFRN) para avalia??o ecotoxicol?gica de sedimento; avaliar a qualidade da ?gua e do sedimento, utilizando os clad?ceros Ceriodaphnia dubia, Ceriodaphnia silvestrii e Hyalella azteca respectivamente, da regi?o do baixo curso do Rio Doce por meio de ensaios ecotoxicol?gicos e an?lises f?sicas e qu?micas de forma a avaliar a interfer?ncia das a??es humanas ao longo do rio. Foram realizadas visitas ? ?rea no per?odo de 2012 a 2014. Os locais de amostragem foram denominados LE, R2, R3, R4 e R5. A avalia??o da qualidade da ?gua e dos sedimentos do baixo curso do rio Doce, trecho localizado entre a Lagoa de Extremoz e a Redinha, por meio de an?lises f?sicas e qu?micas, e de ensaios ecotoxicol?gicos, na ?gua e no sedimento, nos anos de 2012, 2013 e 2014, embasou o conhecimento e respondeu as quest?es de pesquisa: nos testes ecotoxicol?gicos realizados em ?gua e sedimentos h? uma resposta mensur?vel da biota no ambiente aqu?tico, pois a altera??o encontrada nos par?metros f?sicos e qu?micos medidos em ?gua e os resultados negativos encontrados em pelo menos 50% dos testes de toxicidade cr?nica realizados mensalmente no per?odo de um ano evidenciaram o comprometimento da qualidade da ?gua do rio Doce pelo menos em parte do ano, destacando que as diversas atividades desenvolvidas no entorno da drenagem podem estar contribuindo para as varia??es observadas. / The object of this research project was developed on the lower course of the river Doce in the city of Natal, in the districts of Lagoa Azul, Paju?ara and Redinha, along the river Doce, limit with the municipality of Extremoz, Rio Grande do Norte. The region of the Doce river plain is located in the area of environmental protection (ZPA-9). This is one of the ZPA which are not yet regulated and are observed several environmental problems arising from the use and occupation of land, featuring a blatant disregard to environmental legislation and whose protection is hampered due to the lack of specific legal mechanisms. This work aims to deploy and establish the maintenance of cultivation of Hyalella azteca species (Crustacea, Amphipoda) in the laboratory of Ecotoxicology-ECOTOX (UFRN) for ecotoxicological assessment of sediment; assess the quality of the water and the sediment using the cladocerans Ceriodaphnia dubia, Ceriodaphnia silvestrii and Hyalella azteca respectively, the lower course of the Rio Doce for ecotoxicological tests and physical and chemical analyses in order to evaluate the interference of human actions along the river. The visits were carried out in the period from 2012 to 2014. Sampling sites were named LE, R2, R3, R4 and R5. The evaluation of the quality of the water and sediments of the lower course of the Doce river, excerpt located between the lagoon of Extremoz and Redinha, through physical and chemical analyses, and ecotoxicological tests, in water and sediment, in the years 2012, 2013 and 2014, served the knowledge and answered the questions of research: ecotoxicological tests carried out in water and sediments there is a measurable response of biota in aquatic environment because the change found in physical and chemical parameters measured in water and the negative results found in at least 50 of chronic toxicity tests conducted on a monthly basis within one year showed the commitment of the Doce river water quality at least part of the year, noting that the various activities carried out in the vicinity of drainage may be contributing to the observed variations.

Submitted by Napoleana Barros Martins (napoleana_martins@hotmail.com) on 2016-08-08T13:53:10Z No. of bitstreams: 1 DISSERTAÇÃO Janayna Freitas de Araújo Libório.pdf: 1571832 bytes, checksum: e5d5ae8d0422f82a4f3aa0619de957c0 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-08-26T14:47:02Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO Janayna Freitas de Araújo Libório.pdf: 1571832 bytes, checksum: e5d5ae8d0422f82a4f3aa0619de957c0 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2016-08-26T14:49:55Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO Janayna Freitas de Araújo Libório.pdf: 1571832 bytes, checksum: e5d5ae8d0422f82a4f3aa0619de957c0 (MD5) / Made available in DSpace on 2016-08-26T14:49:56Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO Janayna Freitas de Araújo Libório.pdf: 1571832 bytes, checksum: e5d5ae8d0422f82a4f3aa0619de957c0 (MD5) Previous issue date: 2016-02-29 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The pulp of the fruit of the plant species Myrciaria dubia (Kunth) McVaugh, popularly known as camu-camu is known for its high content of ascorbic acid and studies with the peel and seeds have shown that these plant parts also exhibit antioxidant properties due to the presence phenolic compounds of flavonoid type. Knowing this characteristic antioxidant present in the peel and seed Camu Camu, and does not use these residues as raw material; this study aims to verify the feasibility of using the dry extract of the seeds for the development of a semi-solid cosmetic formulation. Tests were performed to characterize the plant drug (loss on drying, particle size analysis, extractive content, total ash, phytochemical screening) for the characterization of extractive solution (pH, density, dry residue) and to characterize the dry extract (particle size analysis, analysis of specific surface area, scanning electron microscopy (SEM), DPPH, ABTS); as well as studies of preliminary stability and accelerated stability for the quality control of the developed formulation. In characterizing the plant drug loss on drying was 8.8%, the particle size was classified as a coarse powder, the extractives yield was 27.9%, total ash of 0.34%. In phytochemical screening the result was strongly positive for phenols, flavônicos glycosides and tannins. The pH of the extraction solution is acidic, the was pH 3.74. The dry extract 7.5% was classified as a fine powder with specific surface area of 1.6448 m² / g and particles with reduced pores of mesoporous type. The result for total phenols of 26.93% and total flavonoid 4.15%. In the SEM images revealed irregular particles in size and shape with a strong tendency to agglomerate. The IC50 of DPPH was 16,77μg / ml and ABTS was 29,77μg/ml. In the development of the formulation, 5 bases were manipulated and from these were tested 15 formulations, 5 formulations were approved for pre-stability tests, and these formulations 5, 1 has been approved and called F1 formulation containing 1% of the dry extract of camu camu seed-embedded base containing 1% shea butter, this was submitted and the preliminary and accelerated stability tests. The F1 introduced a non-Newtonian rheological flow with pseudoplastic and thixotropic behavior. The results enabled the establishment of quality control parameters of plant drug and dry extract. Thus, the characterization of plant drug and its extracts as well as the development of a semi-solid cosmetic formulation containing pure dry extract of the seeds Myrciaria dubia (Kunth) McVaugh opens the way for future phytocosmetics development studies using plant residues this species in a sustainable manner, the seeds being the main bioactive component of the formulation due to its antioxidant potential. / A polpa do fruto da espécie vegetal Myrciaria dubia (Kunth) McVaugh, popularmente conhecida como camu-camu é conhecida por seu elevado conteúdo em ácido ascórbico e estudos com a casca e as sementes têm demonstrado que estas partes vegetais também apresentam propriedades antioxidantes devido a presença de compostos fenólicos do tipo flavonoides. Sabendo-se dessa característica antioxidante presentes na casca e nas sementes de camu-camu e do não aproveitamento desses resíduos como matéria-prima; o presente trabalho tem o objetivo de verificar a viabilidade do uso do extrato seco das sementes para o desenvolvimento de uma formulação cosmética semissólida. Foram realizados ensaios para a caracterização da MPV (perda por dessecação, análise granulométrica, teor de extrativos, cinzas totais, triagem fitoquímica), para a caracterização da solução extrativa (pH, densidade, resíduo seco) e para a caracterização do extrato seco (granulometria a laser, análise SBET, microscopia eletrônica de varredura (MEV), DPPH, ABTS); bem como estudos de Estabilidade preliminar e acelerada para o controle de qualidade da formulação desenvolvida. Na caracterização da MPV a perda por dessecação foi de 8,8%, em na granulometria foi classificada como sendo um pó grosso, o teor de extrativos de 27,9%, cinzas totais de 0,34%. Na triagem fitoquímica o resultado foi fortemente positivo para fenóis, heterosídeos flavônicos e taninos. A solução extrativa é ácida de pH 3,74. O extrato seco 7,5% foi classificado como sendo um pó finíssimo, com área superficial específica de 1.6448 m²/g e partículas com poros reduzidos, do tipo mesoporos. O resultado para fenóis totais de 26,93% e para flavonoides totais de 4,15%. No MEV as imagens revelaram partículas irregulares quanto ao tamanho e a forma e com forte tendência à aglomeração. A CI50 do DPPH foi de 16,77μg/mL e do ABTS foi de 29,77μg/mL. No desenvolvimento da formulação, 5 bases foram manipuladas e partir dessas foram testadas 15 formulações, sendo 5 aprovadas para os testes de pré-estabilidade, e das 5 formulações, 1 foi aprovada e denominada de Formulação 1 (F1) contendo 1% de extrato seco das sementes de camu-camu incorporado à base contendo 1% de manteiga de Karité, esta foi submetida aos testes de estabilidade preliminar e acelerada. A F1 apresentou um fluxo reológico não-newtoniano com comportamento pseudoplástico e tixotropia. Os resultados obtidos possibilitaram o estabelecimento dos parâmetros do controle de qualidade da MPV e do extrato seco. Desta maneira, a caracterização da MPV e de seus extratos, bem como o desenvolvimento de uma formulação cosmética semissólida contendo o extrato seco puro das sementes de Myrciaria dubia (Kunth) McVaugh abre o caminho para futuros estudos de desenvolvimento de fitocosméticos utilizando-se os resíduos dessa espécie, de modo sustentável, sendo o extrato das sementes o principal componente bioativo da formulação devido ao seu potencial antioxidante.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Camu-camu (Myrciaria dubia) is an Amazonia species whose fruits present a high those of acid ascorbic, characteristic that awakes interest in the food industry. To be cultivated, we have therefone, the answers to the use of indole butyric acid (IBA), naphthalene acetic acid (NAA) and indole acetic acid (IAA) in the concentration of 1000 mg.L-, 2000 mg.L-, 3000 mg.L-, 4000 mg.L- e 5000 mg.L- applied for fast immerson as well as the use of vermiculite, sand, carbonized rice rind and plantmax used in the simple form or as a compound on the roots of the camu-camu, was studied in experiments in Boa Vista-RR / O camu-camu (Myrciaria dubia) é uma espécie amazônica cujo os frutos apresentam elevado teor de ácido ascórbico, característica que desperta interesse para a indústria de alimentos. Para ser cultivado, há necessidade de estudos sobre sua propagação. Por isso as respostas ao uso de ácido indolbutírico (AIB), ácido naftaleno acético (ANA) e ácido indolacético (AIA) nas concentrações de 1000 mg.L-, 2000 mg.L-, 3000 mg.L-, 4000 mg.L- e 5000 mg.L-, aplicados por imersão rápida, bem como ao uso de vermiculita, areia, casca de arroz carbonizada e plantmax, empregados na forma simples ou combinada, sobre o enraizamento de estacas de camu-camu, foram estudadas em experimentos conduzidos sob condições de casa de vegetação, em Boa Vista-RR

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The camu-camu is a fruit... / O camu-camu é uma fruta...

No description available.

Occurrences of Phacelia dubia in the Piedmont of South Carolina have been taxonomically enigmatic. Prior work had shown that there was partial reproductive isolation when plants from South Carolina were hybridized with any of the other varieties but evidence of morphological differentiation was lacking. In this study, a new morphological analysis showed South Carolina plants differed significantly in corolla lobe size, sepal size, and leaf dissection in comparisons with neighboring varieties, P. dubia var. dubia and P. dubia var. georgiana. A preponderance of evidence showing differentiation from all other varieties supports recognition of a new variety, P. dubia var. rionensis. Field work and an updated analysis of herbarium records showed the new variety is found in nine contiguous counties in the central and northern Piedmont of South Carolina and two counties in the inner Coastal Plain. We posit a hypothesized biogeographic pathway based on migration of a P. dubia ancestor from the Great Plains or Mexico to the Nashville Basin cedar glades, then to South Carolina piedmont granite outcrops, followed by a migration south to Georgia and Alabama piedmont granite outcrops and a separate migration north to rocky woodlands in North Carolina.

Mercury contamination of the North Fork Holston River below Saltville, Virginia has nearly extirpated most mussel populations. Because natural recovery of these populations has not occurred, this research combined field and laboratory assessments to determine the extent of ecological impairment in the river. In situ 60-day Asian clam (Corbicula fluminea) growth studies in 2005 showed a positive correlation (p=0.03) between low clam growth and sediment mercury levels. Because of severe low flow conditions of the NFHR in late 2005 conductivity dissipation from a point source brine discharge downstream rarely reached background level (~345 µS/cm) and was observed as high as 690 µS/cm 640 m below the discharge site. In addition, conductivity doubled in the river section adjacent to the remediated Ponds 5 and 6 (rm 81.6 and 80.4). Such low flow conditions (mean flow < 50 ft3/sec) occur in the NFHR approximately every five years. This low flow situation also evidenced a thick white flocculent or floc observed to accumulate at the base of the two remediated ponds. Analysis of the flocculent determined it to be high in aluminum (1.9-38 mg/L) and iron (2.0-51.0 mg/L), well above US Environmental Protection Agency Water Quality Criteria limits (0.0087 and 1.0 mg/L, respectively); riverine sediments collected below the accumulated floc also had high levels of calcium (240,000-380,000 mg/kg) and mercury(0.62-1.7 mg/kg). Acute tests with juveniles of Villosa iris and <24-hr old Ceriodaphnia dubia were used to measure the toxicity of the brine discharge, which had a conductivity of ~ 14,000 µS/cm. Results of these tests indicated C. dubia to be more sensitive than V. iris; however, chronic toxicity test results were similar for V. iris and C. dubia. The Lowest Observed Adverse Effect Concentration (LOAEC) for mussel survivorship after 28 days was 10,000 µS/cm, while the LOAEC for growth was 5,000 µS/cm. LOAECs for the C. dubia 7-day chronic were 25 % (survivorship) and 12.5 % (reproduction), while mean conductivity at these two concentrations was 4,054 and 2,211 µS/cm, respectively. Toxicity tests conducted with Pond 6 dyke cut discharges resulted in similar lethal concentrations for C. dubia and V. iris. Forty-eight hour LC50s of these discharges ranged from 12.07-15.95 % for C. dubia, and 17.36-18.95 % for V. iris. Dyke cut discharges also exhibited exceedingly high alkaline pH (11.5-12.2), which caused 100 % mortality to C. dubia in 15 min. The Pond 5 and 6 dyke discharges are the likely source for the flocculent accumulation at the base of the two remediated pond areas. The combined effect of mercury, aluminum and iron, along with periodic fluxes of high conductivity and alkaline pH during low flow conditions may contribute to low mussel recruitment downstream of Saltville, VA. / Master of Science

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-01-16T17:06:20Z No. of bitstreams: 1 ThiagoFariasNobrega_DISSERT.pdf: 1767927 bytes, checksum: 4bc39921c977a9668ed14d461e4bc936 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-01-19T14:01:37Z (GMT) No. of bitstreams: 1 ThiagoFariasNobrega_DISSERT.pdf: 1767927 bytes, checksum: 4bc39921c977a9668ed14d461e4bc936 (MD5) / Made available in DSpace on 2018-01-19T14:01:37Z (GMT). No. of bitstreams: 1 ThiagoFariasNobrega_DISSERT.pdf: 1767927 bytes, checksum: 4bc39921c977a9668ed14d461e4bc936 (MD5) Previous issue date: 2015-02-20 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Os efeitos delet?rios das atividades humanas ao meio ambiente s?o temas de v?rios estudos e consequentemente de mudan?as de paradigmas. Exemplo disso, ? que at? pouco tempo acreditava-se em um infinito poder de dilui??o dos ecossistemas em rela??o aos agentes t?xicos, e pouco se conhecia dos efeitos dos contaminantes aos organismos. Em ?reas de intenso crescimento urbano ? comum o descarte indiscriminado de subst?ncias t?xicas e consequentemente o desequil?brio das din?micas naturais dos ecossistemas. Dentre estes, os lagos s?o complexos e importantes fontes de ?gua superficial, abrigam esp?cies e t?m influ?ncia sobre o clima da regi?o ao seu redor. A Lagoa de Extremoz/RN, litoral Nordeste do Brasil, ? um corpo h?drico localizado numa regi?o de r?pido crescimento urbano. Est? sob influ?ncia de atividades rurais, urbanas e industriais, al?m do regime clim?tico prop?cio a per?odos prolongados de estiagem. O abastecimento de cerca de 300.000 pessoas depende da estabilidade h?drica dessa lagoa. O objetivo deste trabalho foi descrever as rela??es entre par?metros f?sicos, componentes qu?micos e as respostas observadas nos ensaios ecotoxicol?gicos, buscando informa??es sobre as varia??es sazonais. Para isso, foram realizadas, em dois anos, 2013 e 2014, an?lises f?sicas, qu?micas e ecotoxicol?gicas da ?gua e do sedimento superficial, em duas esta??es de amostragem na Lagoa de Extremoz (T1 e T2) e uma no rio Guajiru (T3). Nas amostras de ?gua foram aferidos o pH, turbidez, cloreto, OD, nitrato, nitrito, fosfato reativo total, metais e dureza. Para avaliar a toxicidade das amostras foram usados Ceriodaphnia dubia e C. silvestrii como organismos-teste. No sedimento foram aferidos os teores de carbonato, mat?ria org?nica e metais, caracteriza??o granulom?trica e avaliado os efeitos t?xicos sobre a sobreviv?ncia de Hyalella azteca. Verificou-se no per?odo de estiagem, ocorr?ncia de toxicidade aguda aos Hyalella azteca e nesse mesmo per?odo as concentra??es de metais em ?gua e sedimento tamb?m foram maiores. Em uma an?lise espacial percebeu-se que a maioria das amostras com efeito t?xico aos organismos-teste e com maiores concentra??es de metais foram coletadas na esta??o T2. Portanto, existem evid?ncias de que a qualidade da ?gua da Lagoa de Extremoz esteja diminuindo gradualmente e este processo se agrava pontualmente nos per?odos de menor pluviometria e na esta??o de amostragem T2. / The deleterious effects of human activities on the environment, are subject of several studies and therefore paradigm shifts. Until recently thought up in an infinite power dilution of ecosystems in relation to toxic agents, and little was known of the effects of contaminants to organisms. The intense urban growth contributes to the increase of toxic substances and the instability of the environment dynamics. Among these, the lakes are complex ecosystems important for sustaining life, by stock and provide water, to have influence on microclimates and others. The Extremoz Lake/RN, northeastern Brazil, is a water body located in a fast urban growth area. It is under the influence of rural, urban and industrial activities, further on the climate regime conducive to prolonged periods of drought. The supply of approximately 300.000 people depended on the hydraulic stability of this lake The aim of this study was to describe the relationship between physical, chemical components and the responses observed in the ecotoxicological tests, seeking information on seasonal variations. Physical, chemical and ecotoxicological analysis of water and surface sediment were held in two years, 2013 and 2014, in two sampling stations in Extremoz Lake (T1 and T2) and in Guajiru (T3) river. In all the water samples were measured pH, turbidity, chloride, DO, nitrate, nitrite, the total reactive phosphate, hardness and metals. Ceriodaphnia dubia and C. silvestrii as test organisms were used to evaluate the toxicity of the water samples. In the sediment were measured the carbonate, organic matter, metals, particle size, and evaluated the toxic effects on the survival of Hyalella Azteca. In dry season occurred acute toxicity to Hyalella azteca and in the same period the concentrations of metals in water and sediment were also higher. In a spatial analysis, it was noticed that most of the samples with toxic effects on test organisms and with the highest metal concentrations were collected at T2. So there is evidence that the Extremoz Lake quality is gradually declining and this process is occasionally worsens during periods of lower rainfall and sampling station T2.