Fontes e doses de NPK em milho irrigado sob plantio direto

A utilização de fertilizantes revestidos pode proporcionar menores perdas e maior disponibilidade de nutrientes no solo, passíveis de absorção pelas plantas, tendo em vista a liberação gradativa dos nutrientes. O objetivo deste trabalho foi avaliar o efeito de doses e fontes de N, P e K, nos componentes de produção e na produtividade da cultura de milho irrigado no Cerrado. O delineamento experimental adotado foi o de blocos casualizados, com 4 doses em cobertura (0 kg ha-1 40 kg ha-1 80 kg ha-1e 120 kg ha-1 e 2 fontes (ureia e ureia revestida), para o N; 4 doses (0 kg ha-1 50 kg ha-1 100 kg ha-1e 150 kg ha-1 e 2 fontes (superfosfato triplo e superfosfato triplo revestido), para o P; e 4 doses (0 kg ha-1 40 kg ha-1 80 kg ha-1e 120 kg ha-1 e 2 fontes (cloreto de potássio e cloreto de potássio revestido), para o K, com 4 repetições. Os fertilizantes revestidos por polímeros (ureia, superfosfato triplo e cloreto de potássio) não foram eficientes nas condições edafoclimáticas estudadas, pois proporcionaram resultados semelhantes aos mesmos fertilizantes convencionais, para os teores foliares de N, P e K, componentes de produção e produtividade de grãos de milho irrigado. O incremento das doses de N aumentou linearmente o teor de N foliar, número de espigas por hectare e a produtividade de grãos de milho. A aplicação de doses de K2O e P2O5 não influenciou a produtividade de grãos da cultura.

Síntese de zeólitas tipo ton utilizando um sal de imidazólio como agente direcionador de estrutura

This work reports the synthesis of zeolites with different compositions (pure silica, Si/Ti and Si/Al), via hydroxide and fluoride medium using the cation 1-butyl-3- methylimidazolium as structure directing agent. Initially, the cation was synthesized in chloride form and used for the synthesis in hydroxide medium. An anion-exchange (Cl- for OH-) was required for the synthesis in fluoride medium. Different reactants were used for the formation of gels synthesis, resulting in the crystallization of MFI and TON phases, the latter predominant in many compositions. The cation and synthesized zeolites obtained were characterized by different techniques such as NMR, TG/DTG, XRD, SEM, N2 adsorption and desorption, DRS and EPMA. Besides characterizing the cation and zeolites, the mother liquor of hydroxide synthesis was characterized and it was possible to observe a modification of the cation in the synthesis conditions employed. The materials synthesized in this work can be applied in catalytic reactions and adsorption

Caracterização estrutural de Perovskitas Lax-1AxCoO3 (x=0 e 0,2) ,dopadas com cálcio e bario, por espectroscopia de absorção de raios X (XAS).

In this work, the structures of LaCoO3, La0,8Ba0,2CoO3 and La0,8Ca0,2CoO3 perovskites were characterized as a function of temperature (LaCoO3 structure being analyzed only at room temperature). The characterization of these materials were made by X-Ray Absorption Spectroscopy (XAS), in the cobalt K-edge, taking into account the correlated Einstein model X-ray absorption fine structure (EXAFS). The first part of the absorption spectrum corresponded the X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). These materials were prepared by the combustion method. The combustion products were calcinated at 900 0C, for 6 hours in air. Noted that the sample LaCoO3 at room temperature and samples doped with Calcium and Barium in the temperature range of 50 K to 298 K showed greater distortion to monoclinic symmetry with space group I2/a. However, the sample doped with barium at the temperatures 50 K, 220 K, and 260 K showed a slight distortion to rhombohedral symmetry with space group R-3c. The La0,8Ca0, 2CoO3 structure was few sensitive to temperature variation, showing a higher local distortion in the octahedron and a higher local thermal disorder. These interpretations were in agreement with the information electronic structural on the XANES region and geometric in the EXAFS region

Interações entre a carboximetilcelulose, carbonato de cálcio e bentonita: repercussões sobre as propriedades dos fluidos de perfuração aquosos

The role of carboxymethylcellulose (CMC) in association to calcium carbonate particles (CaCO3) in most water-based drilling fluids is to reduce the fluid loss to the surrounding formation. Another essential function is to provide rheological properties capable of maintaining in suspension the cuttings during drilling operation. Therefore, it is absolutely essential to correlate the polymer chemical structure (degree of substitution, molecular weight and distribution of substituent) with the physical-chemical properties of CaCO3, in order to obtain the better result at lower cost. Another important aspect refers to the clay hydration inhibitive properties of carboxymethylcellulose (CMC) in drilling fluids systems. The clay swelling promotes an undesirable damage that reduces the formation permeability and causes serious problems during the drilling operation. In this context, this thesis consists of two main parts. The first part refers to understanding of interactions CMC-CaCO3, as well as the corresponding effects on the fluid properties. The second part is related to understanding of mechanisms by which CMC adsorption occurs onto the clay surface, where, certainly, polymer chemical structure, ionic strength, molecular weight and its solvency in the medium are responsible to affect intrinsically the clay layers stabilization. Three samples of carboximetilcellulose with different molecular weight and degree of substitution (CMC A (9 x 104 gmol DS 0.7), CMC B (2.5 x 105 gmol DS 0.7) e CMC C (2.5 x 105 gmol DS 1.2)) and three samples of calcite with different average particle diameter and particle size distribution were used. The increase of CMC degree of substitution contributed to increase of polymer charge density and therefore, reduced its stability in brine, promoting the aggregation with the increase of filtrate volume. On the other hand, the increase of molecular weight promoted an increase of rheological properties with reduction of filtrate volume. Both effects are directly associated to hydrodynamic volume of polymer molecule in the medium. The granulometry of CaCO3 particles influenced not only the rheological properties, due to adsorption of polymers, but also the filtration properties. It was observed that the lower filtrate volume was obtained by using a CaCO3 sample of a low average size particle with wide dispersion in size. With regards to inhibition of clay swelling, the CMC performance was compared to other products often used (sodium chloride (NaCl), potassium chloride (KCl) and quaternary amine-based commercial inhibitor). The low molecular weight CMC (9 x 104 g/mol) showed slightly lower swelling degree compared to the high molecular weight (2.5 x 105 g/mol) along to 180 minutes. In parallel, it can be visualized by Scanning Electron Microscopy (SEM) that the high molecular weight CMC (2.5 x 105 g/mol e DS 0.7) promoted a reduction in pores formation and size of clay compared to low molecular weight CMC (9.0 x 104 g/mol e DS 0.7), after 1000 minutes in aqueous medium. This behavior was attributed to dynamic of interactions between clay and the hydrodynamic volume of CMC along the time, which is result of strong contribution of electrostatic interactions and hydrogen bounds between carboxylate groups and hydroxyls located along the polymer backbone and ionic and polar groups of clay surface. CMC adsorbs on clay surface promoting the skin formation , which is responsible to minimize the migration of water to porous medium. With the increase of degree of substitution, it was observed an increase of pores onto clay, suggesting that the higher charge density on polymer is responsible to decrease its flexibility and adsorption onto clay surface. The joint evaluation of these results indicate that high molecular weight is responsible to better results on control of rheological, filtration and clay swelling properties, however, the contrary effect is observed with the increase of degree of substitution. On its turn, the calcite presents better results of rheological and filtration properties with the decrease of average viii particle diameter and increase of particle size distribution. According to all properties evaluated, it has been obvious the interaction of CMC with the minerals (CaCO3 and clay) in the aqueous medium

Caracterização química e toxicológica da água produzida descartada em plataformas de óleo e gás na costa brasileira e seu comportamento dispersivo no mar

The production of oil and gas is usually accompanied by the production of water, also known as produced water. Studies were conducted in platforms that discharge produced water in the Atlantic Ocean due to oil and gas production by Petrobras from 1996 to 2006 in the following basins: Santos (Brazilian south region), Campos (Brazilian southeast region) and Ceara (Brazilian northeast region). This study encompasses chemical composition, toxicological effects, discharge volumes, and produced water behavior after releasing in the ocean, including dispersion plumes modeling and monitoring data of the marine environment. The concentration medians for a sampling of 50 samples were: ammonia (70 mg L-1), boron (1.3 mg L1), iron (7.4 mg L-1), BTEX (4.6 mg L-1), PAH (0.53 mg L-1), TPH (28 mg L-1); phenols (1.3 mg L-1) and radioisotopes (0.15 Bq L-1 for 226Ra and 0.09 Bq L-1 for 228Ra). The concentrations of the organic and inorganic parameters observed for the Brazilian platforms were similar to the international reference data for the produced water in the North Sea and in other regions of the world. It was found significant differences in concentrations of the following parameters: BTEX (p<0.0001), phenols (p=0.0212), boron (p<0.0001), iron (p<0.0001) and toxicological response in sea urchin Lytechinus variegatus (p<0.0001) when considering two distinguished groups, platforms from southeast and northeast Region (PCR-1). Significant differences were not observed among the other parameters. In platforms with large gas production, the monoaromatic concentrations (BTEX from 15.8 to 21.6 mg L-1) and phenols (from 2 to 83 mg L-1) were higher than in oil plataforms (median concentrations of BTEX were 4.6 mg L-1 for n=53, and of phenols were 1.3 mg L-1 for n=46). It was also conducted a study about the influence of dispersion plumes of produced water in the vicinity of six platforms of oil and gas production (P-26, PPG-1, PCR-1, P-32, SS-06), and in a hypothetical critical scenario using the chemical characteristics of each effluent. Through this study, using CORMIX and CHEMMAP models for dispersion plumes simulation of the produced water discharges, it was possible to obtain the dilution dimension in the ocean after those discharges. The dispersion plumes of the produced water modelling in field vicinity showed dilutions of 700 to 900 times for the first 30-40 meters from the platform PCR-1 discharge point; 100 times for the platform P-32, with 30 meters of distance; 150 times for the platform P-26, with 40 meters of distance; 100 times for the platform PPG-1, with 130 meters of distance; 280 to 350 times for the platform SS-06, with 130 meters of distance, 100 times for the hypothetical critical scenario, with the 130 meters of distance. The dilutions continue in the far field, and with the results of the simulations, it was possible to verify that all the parameters presented concentrations bellow the maximum values established by Brazilian legislation for seawater (CONAMA 357/05 - Class 1), before the 500 meters distance of the discharge point. These results were in agreement with the field measurements. Although, in general results for the Brazilian produced water presented toxicological effects for marine organisms, it was verified that dilutions of 100 times were sufficient for not causing toxicological responses. Field monitoring data of the seawater around the Pargo, Pampo and PCR-1 platforms did not demonstrate toxicity in the seawater close to these platforms. The results of environmental monitoring in seawater and sediments proved that alterations were not detected for environmental quality in areas under direct influence of the oil production activities in the Campos and Ceara Basin, as according to results obtained in the dispersion plume modelling for the produced water discharge

Caracterização química e toxicológica da água produzida descartada em plataformas de óleo e gás na costa brasileira e seu comportamento dispersivo no mar

The production of oil and gas is usually accompanied by the production of water, also known as produced water. Studies were conducted in platforms that discharge produced water in the Atlantic Ocean due to oil and gas production by Petrobras from 1996 to 2006 in the following basins: Santos (Brazilian south region), Campos (Brazilian southeast region) and Ceara (Brazilian northeast region). This study encompasses chemical composition, toxicological effects, discharge volumes, and produced water behavior after releasing in the ocean, including dispersion plumes modeling and monitoring data of the marine environment. The concentration medians for a sampling of 50 samples were: ammonia (70 mg L-1), boron (1.3 mg L1), iron (7.4 mg L-1), BTEX (4.6 mg L-1), PAH (0.53 mg L-1), TPH (28 mg L-1); phenols (1.3 mg L-1) and radioisotopes (0.15 Bq L-1 for 226Ra and 0.09 Bq L-1 for 228Ra). The concentrations of the organic and inorganic parameters observed for the Brazilian platforms were similar to the international reference data for the produced water in the North Sea and in other regions of the world. It was found significant differences in concentrations of the following parameters: BTEX (p<0.0001), phenols (p=0.0212), boron (p<0.0001), iron (p<0.0001) and toxicological response in sea urchin Lytechinus variegatus (p<0.0001) when considering two distinguished groups, platforms from southeast and northeast Region (PCR-1). Significant differences were not observed among the other parameters. In platforms with large gas production, the monoaromatic concentrations (BTEX from 15.8 to 21.6 mg L-1) and phenols (from 2 to 83 mg L-1) were higher than in oil plataforms (median concentrations of BTEX were 4.6 mg L-1 for n=53, and of phenols were 1.3 mg L-1 for n=46). It was also conducted a study about the influence of dispersion plumes of produced water in the vicinity of six platforms of oil and gas production (P-26, PPG-1, PCR-1, P-32, SS-06), and in a hypothetical critical scenario using the chemical characteristics of each effluent. Through this study, using CORMIX and CHEMMAP models for dispersion plumes simulation of the produced water discharges, it was possible to obtain the dilution dimension in the ocean after those discharges. The dispersion plumes of the produced water modelling in field vicinity showed dilutions of 700 to 900 times for the first 30-40 meters from the platform PCR-1 discharge point; 100 times for the platform P-32, with 30 meters of distance; 150 times for the platform P-26, with 40 meters of distance; 100 times for the platform PPG-1, with 130 meters of distance; 280 to 350 times for the platform SS-06, with 130 meters of distance, 100 times for the hypothetical critical scenario, with the 130 meters of distance. The dilutions continue in the far field, and with the results of the simulations, it was possible to verify that all the parameters presented concentrations bellow the maximum values established by Brazilian legislation for seawater (CONAMA 357/05 - Class 1), before the 500 meters distance of the discharge point. These results were in agreement with the field measurements. Although, in general results for the Brazilian produced water presented toxicological effects for marine organisms, it was verified that dilutions of 100 times were sufficient for not causing toxicological responses. Field monitoring data of the seawater around the Pargo, Pampo and PCR-1 platforms did not demonstrate toxicity in the seawater close to these platforms. The results of environmental monitoring in seawater and sediments proved that alterations were not detected for environmental quality in areas under direct influence of the oil production activities in the Campos and Ceara Basin, as according to results obtained in the dispersion plume modelling for the produced water discharge

Efeito da aplicação foliar de boro e zinco sobre a produção e os teores de SST e ATT dos frutos da Pereira-Japonesa e da pinheira

Pulverizações foliares com produtos contendo micronutrientes, dentre os quais os produtos quelatizados, são utilizadas com relativa freqüência em frutíferas, sem o embasamento científico adequado, principalmente entre os agricultores mais tecnificados. Neste contexto, o objetivo deste trabalho foi verificar o efeito da aplicação via foliar de B e Zn sobre a produção e os teores de SST e ATT dos frutos da Pereira-Japonesa e da Pinheira. O experimento foi conduzido numa área irrigada, situada no cinturão verde do município de Ilha Solteira-SP. O solo da área foi classificado como Podzólico Vermelho-Escuro. Foram utilizadas plantas de Pereira-Japonesa, cultivar Okussankichi e de Pinheira. Os tratamentos utilizados foram: T1. apenas água; T2. ácido bórico; T3. sulfato de zinco; T4. T2 + T3; T5. ácido bórico + uréia + ácido cítrico + EDTA; T6. sulfato de zinco + uréia + ácido cítrico + EDTA; T7. T5 + T6; T8. ácido bórico + uréia + ácido cítrico + EDTA + molibdato de sódio + enxofre + cloreto de cálcio; T9. sulfato de zinco + ácido cítrico + EDTA + sulfato de Fe + sulfato de Mn + sulfato de Mg, e T10. T8+T9. Foram utilizadas doses de 110 g ha-1 de B e 250 g ha-1 de Zn, em cada aplicação. O delineamento experimental adotado foi o de blocos ao acaso, com quatro repetições e, para comparação de médias, foi utilizado o teste de Tukey. Com base nos resultados obtidos, pode-se concluir que: 1) a produção e os teores de SST e ATT dos frutos da pereira-japonesa e da pinheira não foram influenciados pela aplicação foliar de B e de Zn; b) a mistura de ácido bórico com quelatos foi eficiente no fornecimento de B às plantas de pereira- japonesa, o mesmo não ocorrendo para pinheira, c) o sulfato de zinco + produtos quelatizantes foram eficientes no aumento dos teores foliares de Zn somente na pereira.

Uso de reguladores de crescimento no desenvolvimento e produção de crotalária

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

Reguladores de crescimento e seus efeitos sobre a qualidade fisiológica de sementes e crescimento de plântulas de crotalária

Information regarding the use of growth regulators in sunn hemp is still scarce, especially on the physiologic quality of seeds and growth seedlings. In this aspect, product knowledge and application rate stands out as relevant factors in production of quality seeds. This work aimed to evaluated the effect of the foliar application of growth regulators (mepiquat chloride, etil-trinexapac and paclobutrazol) in different rates (0; 75; 150; 225 and 300 g ha(-1)), on the physiological quality of seeds and growth seedlings of Crotalaria juncea cultivated in no-tillage system. The treatments were disposed in randomized complete block design in factorial scheme 3 x 5 (regulators x rates of application), with four replications. The results were submitted to the variance analysis, with the growth regulators compared by Tukey test and the rates for polynomial regression. Not if recommended the application of mepiquat chloride in sunn hemp culture by reducing the potential of seeds germination and dry biomass of seedlings. The etil-trinexapac must be applied in rate of 300 g ha(-1), based on the reduction of moisture content and the electrical conductivity of seeds, the greater total length of seedlings and dry biomass of seedlings. The paclobutrazol must be applied in rate of 75 g ha(-1), considering the potential and speed of seeds germination.

Efeitos da administração subaracnóidea de grandes volumes de lidocaína a 2% e ropivacaína a 1% sobre a medula espinhal e as meninges: estudo experimental em cães

JUSTIFICATIVA E OBJETIVOS: A injeção de grandes volumes de anestésico local no espaço subaracnóideo, após punção dural acidental, é complicação da anestesia peridural. O objetivo desta pesquisa foi investigar as possíveis alterações clínicas e histológicas desencadeadas por grandes volumes de lidocaína a 2% e ropivacaína a 1%, simulando injeção subaracnóidea acidental, em cães. MÉTODO: Vinte e um cães foram distribuídos aleatoriamente em 3 grupos, que receberam por via subaracnóidea: G1 - cloreto de sódio a 0,9%; G2 - lidocaína a 2% e G3 - ropivacaína a 1%. A punção subaracnóidea foi realizada no espaço intervertebral L6-L7. O volume de anestésico local administrado foi de 1 ml para cada 10 cm de distância entre a protuberância occipital e o espaço lombossacral (5 - 6,6 ml). Após 72 horas de observação clínica os animais foram sacrificados e foi removida a porção lombossacral da medula para exame histológico, por microscopia óptica. RESULTADOS: Nenhum animal do G1 apresentou alterações clínicas ou histológicas da medula espinhal. Foram observados dois casos de necrose do tecido nervoso em G2, porém mudanças clínicas, em somente um desses cães e em outros dois animais que não apresentaram alterações histológicas. Foi encontrada necrose focal do tecido nervoso medular em um animal de G3. Todos os animais de G3 permaneceram clinicamente normais. CONCLUSÕES: Conclui-se que grandes volumes de lidocaína a 2% determinaram alterações clínicas e histológicas mais intensas que os de ropivacaína a 1%.

Efeitos da dexmedetomidina sobre o sistema renal e sobre a concentração plasmática do hormônio antidiurético: estudo experimental em cães

JUSTIFICATIVA E OBJETIVOS: A insuficiência renal aguda peri-operatória é responsável por elevada taxa de morbidade e mortalidade. Os fármacos alfa2-agonistas aumentam o débito urinário e promovem boa estabilidade hemodinâmica nesse período. O objetivo desta pesquisa foi estudar os efeitos renais e sobre a concentração plasmática do hormônio antidiurético (HAD) provocados pela dexmedetomidina no cão anestesiado. MÉTODO: Trinta e seis cães adultos, anestesiados com propofol, fentanil e isoflurano, foram divididos aleatoriamente em três grupos que receberam, de modo encoberto: G1 - injeção de 20 mL de solução de cloreto de sódio a 0,9%, em 10 minutos, seguida de injeção de 20 mL da mesma solução em uma hora; G2 - injeção de 20 mL de solução de cloreto de sódio a 0,9% contendo dexmedetomidina (1 µg.kg-1), em 10 minutos, seguida de injeção de 20 mL da mesma solução, com a mesma dose de dexmedetomidina (1 µg.kg-1), em uma hora e G3 - injeção de 20 mL de solução de cloreto de sódio a 0,9% contendo dexmedetomidina (2 µg.kg-1) em 10 minutos, seguida de injeção de 20 mL da mesma solução, com a mesma dose de dexmedetomidina (2 µg.kg-1), em uma hora. As variáveis renais, hemodinâmicas e a concentração plasmática do HAD foram estudadas em quatro momentos: M1 (controle) - imediatamente após o período de estabilização; M2 - após a injeção inicial de 20 mL da solução em estudo, em 10 minutos, coincidindo com o início da injeção da mesma solução, em uma hora; M3 - 30 minutos após M2 e M4 - 30 minutos após M3. RESULTADOS: A dexmedetomidina reduziu a freqüência cardíaca e promoveu estabilidade hemodinâmica, mantendo constante o débito cardíaco. Houve elevação do débito urinário no G2 e G3, em comparação com o G1. A osmolalidade urinária no G2 e G3 foi menor no M3 e M4 em relação ao M1 e M2. A depuração de água livre aumentou no G3. A concentração plasmática do HAD diminuiu no G3, apresentando valores mais baixos que os observados no G1 e G2 em M2 e M4. CONCLUSÕES: Os cães anestesiados com baixas doses de dexmedetomidina promovem diurese hídrica por inibir a secreção do hormônio antidiurético, havendo potencial para proteção renal em eventos isquêmicos.

Viabilidade da cultura Cnidoscolus quercifolius POHL para produção de Biodiesel no semiárido nordestino

The northeastern semiarid is a region that presents a serious picture stagnation or slowness of the economic growth, beyond the presence of social pointers below of the averages national and regional. The half-dryness conditions become the improper region for many agricultural cultures, what it affects the local populations directly, as well as the economy that is based mainly on agriculture. Cnidoscolus quercifolius Pohl, popularly know as favelone is a native species of the semiarid region that withholds great potential for the development of the region in virtue of its multiple uses. Being an oleaginous, its production in familiar farmings makes with that biodiesel either for the misery an important alternative eradication for the possibility of occupation of enormous contingents of people. The present study it aims at to evaluate the germination of the faveleira without thorns under conditions of water and saline stresses, main stresses which the vegetal species of the semiarid one are submitted; beyond verifying the acceptance of the species for agriculturists of a cooperative in the city of Apodi/RN. The methodology used for germination corresponds to using treatments with polyethylene glycol and sodium chloride to assess water and salt stress respectively, being held in rolo. O system approach used for the verification of acceptance of faveleira was the use of interview with farmers cooperative in the study area determined. In this direction it was verified that the faveleira is a resistant species the conditions of drought and salinity of the ground, factor of great relevance, since one is about a species with high added value, making possible the development for the semiarid region. It was verified that the agriculturists are favorable the introduction of the faveleira and reveal receptive the idea to cultivate a species with potential for production of biodiesel

Análise da toxicidade no açude Riacho da Cachoeira, Lajes Pintadas (RN): um desafio interdisciplinar

Contamination by complex mixtures of various origins has been explored and studied for decades. Radon is a naturally occurring environmental contaminant that causes carcinogenic effects. These emissions can cause mutations in the lung tissue, which can initiate a carcinogenic process. Thus the dam Creek Falls, located in the municipality of Lajes Pintadas, was chosen for the development of this study, since cancer rates in the region reach 9% of the population annually, with this, the main objective of this study was evaluate the mutagenicity and toxicity of Riacho da Cachoeira damunder the influence of radon. The methodology ecotoxicological tests were performed with Ceriodaphinia dubia, as well as tests with Tradescantia pallida genotoxicologicos and Oreochromis niloticus. To understand how the population of Pintadas Slabs realizes the environment, we performed a study of environmental perception. The test results indicated that the reservoir water is toxic to test organimos exposed, found heavy metals, chloride, total and fecal coliforms as well as radon levels above the maximum allowed under Brazilian law. These results can be justified because it is so complex samples composed of different compounds that interact only with each other or causing synergistic effects. It was concluded that the dam Creek Waterfall, is contaminated with radon, as well as heavy metals, coliforms and chloride, causing toxic effects to the natural community. Thus, further studies should be performed with the human population of the region, to verify that the high rates of cancer in the population of the municipality may be linked to the presence of natural radiation. Thus, it is expected that the competent bodies that administer the municipality of Lajes Pintadas take reasonable steps to minimize risks and ensure the health of the community that still makes use of the weir

Horticultura no baixo curso do Rio Doce, zona norte do Natal/RN: avaliação da qualidade da água por meio de ensaios ecotoxicológicos

The research is developed in areas of horticulture in the city of Natal, in the neighborhoods of Lagoa Azul, Pajuçara and Redinha, along the Doce River, border area with Extremoz city, Rio Grande do Norte State. The region of the fluvial plain of Doce River is located in an Environmental Protection Zone (ZPA-9). This is one of the ZPA which is not under the regulatory marks and there are several environmental problems caused by use and land occupation, featuring an evident disregard of environmental laws and whose protection is hindered by the lack of specific legal mechanisms. This study aims to provide an overview of the use of pesticides in the lower course of the Doce River, in Natal, Rio Grande do Norte, and to assess environmental degradation in the area through chronic toxicity tests using the microcrustaceous Ceriodaphnia dubia Richard 1894 (Cladocera, Crustacea) as test organism. Visits were made to the area in 2009 and 2010. To obtain information a diagnosis of the local situation was accomplished based on personal observation and non-participatory photographic record, with the aim of assessing the environmental characteristics, population diversity and work processes of horticulturists. During the visits four different points of the Doce River were chosen to collect water for ecotoxicological tests and survey of physico-chemical parameters (dissolved oxygen, pH, chloride, turbidity, conductivity and temperature), which were measured in the field using Multiparameter Probe (TROLL 9500). The adverse effects of pesticide use in the lower course of the Doce River is a major problem for both the environmental and human health, since many of the substances and active principles that enter in the composition of the products are synthesized molecules whose effects can only be evaluated through different studies on their actions and behavior at short, medium or long term

Metais pesados no caranguejo Ucides cordatus (Linnaeus, 1763) e ecotoxicologia de sedimentos do estuario dos Rios Jundiai e Potengi - RN

This study is conducted in the estuary of the rivers Jundiaí and Potengi, one of the most important estuaries of Rio Grande do Norte, which suffers a strong anthropogenic influence from neighboring cities. According to Resolution 344/2005 environments that have high concentrations of metals such as arsenic, cadmium, lead and mercury need ecotoxicological tests. This study aims to evaluate the heavy metals contamination in the estuary through analysis of sediment collected at four points distributed from Macaíba to Natal city, and in the crab Uçá, Ucides cordatus. The study aims also to evaluate the effects of sediment toxicity in the tests organisms Leptocheirus plumulosus. To obtain data about the concentrations of heavy metals in the environment, sediments were collected in January and May 2011 and crab Uçá was collected in June 2011. On the other hand the monitoring was carried out through toxicological tests with sediment collected from July to October 2011. During the collection of sediment samples the physico-chemical parameters of water (dissolved oxygen, pH, chloride, turbidity, conductivity and temperature) were measured by using multi-parametric probe (TROLL 9500). It was possible to identify contamination by metals such as lead, cadmium, arsenic and copper both in the sediment and in the Uçá crab, which characterizes that the consumption of this crustacean may be a risk to human health. Once the concentrations of metals were identified, toxicology tests were performed and revealed toxic effect to organisms in at least one of the four months studied. Point 2 was classified as toxic in three of the four months studied . The heavy metal contamination is a risk to the environment, to aquatic organisms and to the community which survives of resources taken from the environment