El cambio climático se “sumerge” al interior del océano a través de la formación de masas de agua en distintas regiones. Tal es el caso del Agua Intermedia Antártica (AAIW), la masa de agua más extendida del océano global, presente a profundidades intermedias en todas las cuencas oceánicas. El AAIW, formada al norte del Frente Polar Antártico y en las costas de Chile, estaría jugando un rol importante en la distribución de calor y sal, pero en especial de gases como el oxígeno, dióxido de carbono y óxido nitroso, por mencionar algunos | Published | Agua Intermedia Antártica

Com o objetivo de avaliar a eficiência do uso de água pelo meloeiro no sistema hidropônico NFT realizaram-se dois experimentos em duas épocas distintas (setembro de 2003 a janeiro de 2004, época I e janeiro a abril de 2004, época II). Os experimentos foram conduzidos em casa de vegetação em área da Universidade Federal de Santa Maria, Santa Maria-RS. As características avaliadas foram: consumo hídrico das plantas e eficiência no uso de água da cultura. A eficiência no uso de água do meloeiro foi máxima no subperíodo de floração (4,19g de FS m-3) na época I e no final do estádio vegetativo (8,22g de FS m-3) para a época II, associados a uma elevada taxa de crescimento e baixo consumo hídrico nesses estádios.

This work analyzes the formation, expansion and management of the water supply system of the city of Marabá, in the State of Pará. In the mid-‘70s, the city became the locus of a strong demographic growth, exacerbated by an intensive migration process, resulting from several public initiatives connected with a policy of national integration This policy comprised the development of infrastructure such as roads, hydroelectric plants, official colonization plans, implementation of big projects, as the mining complex of Carajas, incentives to agriculture and cattle-raising and timber exploration. This demographic boom increased by four times the city’s urban population creating a big impact in the supply of public services, overburdening, inclusive, the water supply system. Aiming to contribute to the debate on the question of water supply in the aforementioned city, we concentrated our efforts to analyze how the city’s water supply is being made throughout these years. Its present supply structure, which areas are covered by the services provided by the Company of Water Supply of the State of Pará and which are not and which alternatives of water supply are being adopted to secure water supply services in areas not covered by the official water supply system. | Análise da formação, expansão e a gestão do abastecimento de água na cidade de Marabá. Esta cidade, locus de toda uma problemática relacionada à grande explosão demográfica provocada a partir da década de 70, pelo intenso processo migratório estimulado por diversas ações públicas ligadas à política nacional de integração nacional que perpassa por obras de infraestrutura como estradas, hidrelétricas, projetos de colonização oficial, implantação de grandes projetos como ferro-carajás, agropecuários e de exploração de madeira. Essa explosão demográfica quadruplicou a área urbana da cidade impactando profundamente a oferta de serviços públicos, entre os quais o abastecimento de água. Este estudo visa contribuir para com o debate relacionado à gestão de abastecimento de água, procuramos analisar como se deu o abastecimento de água na cidade ao longo do tempo, como ele se apresenta, quais as áreas atendidas pela Companhia de Saneamento do Pará e os tipos de abastecimento alternativos nas áreas que não tem abastecimento.

Human consumption of water outside of the microbiological standards for drinking constitutes a health and disease risk factor. Through the process of infiltration in the soil, groundwater may be contaminated by the waste generated by human activity and deposited in the soil, waterways or air. The consumption of water in natura, captured in a spring, may lead to the risk of disease. One of the alternative technologies for disinfecting water that has shown promise is the generation of an oxidant solution in loco. The electrochemical reaction of sodium chloride produces oxidizing gases, which reacts with the water to produce the hypochlorite ion in balance with hypochlorous acid, along with traces of other oxidants. In the present study the development of a device based on an imported model that uses this type of technology wassought in order to reduce the cost of acquisition and makeit more available to disadvantaged communities with water quality issues. The evaluation of the efficiency of this technology in disinfecting water with different qualities (color and turbidity) was also sought, using total coliforms and Escherichia coli as indicator organisms of contamination. In each experimentthe quality of untreated water, and water after adding the oxidant was examined on turbidity, true color, residual chlorine, pH, temperature, and quantification of microorganism indicators. In the experiments performed we found that the adapted equipment showed to be as efficient in the production of disinfectant agents as the original equipment. In the microbiological assays performed on water contaminated with E. coli (synthesized water in a laboratory and natural) and total coliforms (natural water), the inactivation of these organisms was observed to be effective with the use of gases that came from the adapted equipment, taking into account the content of chlorine in water treated with the equipment. | Human consumption of water outside of the microbiological standards for drinking constitutes a health and disease risk factor. Through the process of infiltration in the soil, groundwater may be contaminated by the waste generated by human activity and deposited in the soil, waterways or air. The consumption of water in natura, captured in a spring, may lead to the risk of disease. One of the alternative technologies for disinfecting water that has shown promise is the generation of an oxidant solution in loco. The electrochemical reaction of sodium chloride produces oxidizing gases, which reacts with the water to produce the hypochlorite ion in balance with hypochlorous acid, along with traces of other oxidants. In the present study the development of a device based on an imported model that uses this type of technology wassought in order to reduce the cost of acquisition and makeit more available to disadvantaged communities with water quality issues. The evaluation of the efficiency of this technology in disinfecting water with different qualities (color and turbidity) was also sought, using total coliforms and Escherichia coli as indicator organisms of contamination. In each experimentthe quality of untreated water, and water after adding the oxidant was examined on turbidity, true color, residual chlorine, pH, temperature, and quantification of microorganism indicators. In the experiments performed we found that the adapted equipment showed to be as efficient in the production of disinfectant agents as the original equipment. In the microbiological assays performed on water contaminated with E. coli (synthesized water in a laboratory and natural) and total coliforms (natural water), the inactivation of these organisms was observed to be effective with the use of gases that came from the adapted equipment, taking into account the content of chlorine in water treated with the equipment. | Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Los metales pesados (MP) pueden afectar las relaciones hídricas de la planta de muchas formas. El Hg inhibe la actividad de las acuaporinas, proteínas que forman los canales transportadores de agua, y de esta manera afecta la conductividad a nivel celular y de tejidos en zonas específicas de la raíz, así como el volumen de las células guarda modificando los movimientos estomáticos. Además, junto con otros metales pesados, el Hg produce cambios morfológicos como el acortamiento o modificación en la elasticidad de las raíces, disminuyendo el área efectiva para la toma de agua. En hojas, el cambio en el número de estomas y de tricomas causado por el Hg, altera la tasa de transpiración. En este artículo se revisa el efecto del Hg sobre el transporte de agua en la planta a nivel celular y su relación con el estatus hídrico de ésta. Además, se presentan avances recientes en el conocimiento de las acuaporinas basados en la utilización del Hg como inhibidor de su actividad.Palabras clave adicionales: acuaporinas, conductividad hidráulica, raíces, estomas. | Heavy metals could affect hydric relationships in plants in many ways. Mercury inhibits activity of aquaporins, the proteins that form the chanels-transporters of water and, thus, affects water conductivity of cells and tissues of special root zones as well as volume of guard cells modifying stomatal movements. Mercury produces morphological changes in plants, the effects typical for other heavy metals, such as shortening of root or decrease in root elasticity, thus reducing effective area for water absorption. In leaves, the changes in number of stomata and trichomes caused by the effects of Hg alter the transpiration rates. In the present article, the effects of Hg over the water transport in plants at cellular level and whole hydric status of plants are revised. Additionally, the recent studies on aquaporin functioning are discussed, with Hg used as an agent to inhibit aquaporin activity.

The objective of this work was to determine the best condi ons for the water immersion test and to evaluate its e ciency for applica on on rice seeds. Five seed lots of cv. rice IRGA 417 were used, which were submited to immersion treatments tests for periods of 24, 48, 72, 96 and 120 hours at 25 C. After treatments, germina on test, par al and total length of seedlings and seedlings dry mater were accomplished. Water immersion test in the condi on of 24 hours of immersion of the seeds at 25 C, with evalua on of normal seedlings developed, is viable to evaluate vigor on rice seeds. | O presente trabalho teve por objeivo determinar as condiç es para a conduç o do teste de imers o em água como teste de vigor em sementes de arroz. Uilizaramrse cinco lotes de sementes de arroz cv. IRGA 417, caracterizados quanto à qualidade fisiológica inicial e submeidos aos tratamentos de imers o em água por períodos de 24, 48, 72, 96 e 120 horas a 25 C. Após os tratamentos, foram realizadas as avaliaç es de germinaç o, comprimento da raiz, parte aérea e total e massa seca das plântulas. O teste de imers o em água na condiç o de 24 horas a 25 C, seguido da avaliaç o da formaç o de plântulas normais, é viável para avaliar o potencial fisiológico de sementes de arroz.

Se analizó la calidad del agua para consumo humano en las épocas seca y lluviosa del 2007 en 21 acueductos del Municipio de Valle de Ángeles, microcuenca del río La Soledad, Honduras. Los parámetros analizados fueron temperatura, turbiedad, pH, fosfatos, nitratos, sólidos suspendidos, sólidos totales disueltos, oxígeno disuelto, demanda bioquímica de oxígeno, demanda química de oxígeno y coliformes totales. La mayoría de parámetros analizados mostraron diferencias significativas entre épocas y entre acueductos, lo que sugiere la importancia y necesidad de realizar el monitoreo de calidad de agua en ambas épocas y en todos los acueductos. La turbiedad, pH, sólidos suspendidos, oxígeno disuelto y coliformes totales presentaron niveles superiores a los establecidos en la normas de calidad de agua para consumo humano en Honduras. Los niveles de coliformes totales fueron altos en la mayoría de los acueductos y en las dos épocas de muestreo, pero superiores en la época lluviosa lo que posiblemente ocasiona el incremento de personas atendidas en los centros de salud debido a enfermedades de origen hídrico reportadas en ese periodo. Es necesario aumentar los esfuerzos en la gestión integral de la microcuenca para mejorar la calidad del agua. | The quality of water for human consumption was analyzed during the dry and rainy seasons of 2007 in 21 aqueducts, in the microwatershed of La Soledad River, municipality of Valle de Angeles, Honduras. Parameters analyzed were temperature, turbidity, pH, phosphates, nitrates, suspended solids, dissolved total solids, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand and total coliforms. Most of the parameters evaluated showed significant differences between seasons and aqueducts that suggests the importance and need of monitoring water quality in both seasons and in all aqueducts. Turbidity, pH, suspended solids, dissolved oxygen and total coliforms presented levels higher than accepted under Honduran standards for human consumption. Total coliform levels were high in all aqueducts and in both seasons, but higher in the rainy season, possibly, causing an increment in the number of people attended at health centers due to waterrelated diseases. It is necessary to increase effort in the integral management of the watershead to improve water quality for human consumption.