O objetivo do presente trabalho foi verificar a influência do uso de água salina nos atributos químicos do solo e no estado nutricional da mandioqueira. O trabalho foi conduzido na área experimental de Irrigação e Drenagem do IF Baiano, Campus de Senhor do Bonfim, BA (10o 28’S, 40o 11’W e 550 m). O delineamento experimental utilizado foi o inteiramente casualizado constando de sete tratamentos e três repetições. Os tratamentos consistiram de uma testemunha (sequeiro), um tratamento irrigado com água potável (100% da ETc) e cinco tratamentos irrigados com água salina com CE de 3 dS m-1 variando as lâminas aplicadas: 110, 120, 130, 140 e 150% da ETc. O uso de água salina aumentou a percentagem de sódio trocável, a razão de adsorção de sódio e a condutividade elétrica do solo, tanto na 0-0,20 como na 0,20-0,40 m de profundidade. Quanto ao estado nutricional foliar da mandioqueira, os tratamentos influenciaram apenas nos teores de cálcio, magnésio e cloro.<br>The purpose of this study was to assess the influence of saline water on chemical properties of the soil and nutritional attributes of cassava. The work was conducted in the area of Irrigation and Drainage of IF Baiano, Campus de Senhor do Bonfim, BA (10° 28’S, 40° 11’W and 550 m). The experimental design was completely randomized, consisting of seven treatments and three replicates. The treatments consisted of control (rainfed), a treatment irrigated with drinking water (100% of ETc) and five treatments irrigated with saline water of 3 dS m-1 with varying water depths: 110, 120, 130, 140 and 150% of ETc. The use of saline water increased the exchangeable sodium percentage, the sodium adsortion ratio and the electrical conductivity of the soil in both 0-0.20 and 0.20-0.40 m dephts. Regarding the leaf nutritional status of cassava, the treatments influenced only the contents of calcium, magnesium and chlorine.

Water quality testing (in situ and in laboratory) was conducted on 50 wells across the state of Campeche. Further to this (to aid in water quality management and policy), a GIS was implemented to i) approximate Zones of Contribution (ZOC) for well recharge which in turn supplies water for main cities in the state and ii) perform predictive land change modeling on these ZOC’s to predict the future effect of non-point source pollution. Due to natural geohydrological conditions, values of TDS, pH, and SO4 exceeded Mexican regulations in roughly one third of the wells. Although most wells do not exceed the permissible limits of nutrients and heavy metals, some wells show worryingly high levels of NO2-, TP, and Pb, indicators of pollution from anthropogenic sources. All wells were contaminated by coliform bacteria. Poor water quality in some of the main water sources in the state is mainly due to the proliferation of open dumps and the lack of sewage infrastructure, as well as the ongoing conversion of vegetated land to agriculture into the ZOC’s. It is shown that unless remedial measures are implemented, human activities will continue to extend into these areas, placing the state’s water supply at even higher risk of contamination. | Se analizó la calidad del agua (in situ y laboratorio) de 50 pozos en todo el Estado. Además, se implemento un SIG (para establecer políticas y pautas de manejo de la calidad del agua), consistente en i) delimitar de manera preliminar la zona que contribuye agua a los pozos (ZOC) que abastecen las principales ciudades y ii) modelar las tendencias del uso del suelo para predecir el efecto futuro de las fuentes dispersas de contaminación. Debido a condiciones naturales geohidrológicas, los valores de STD, pH y SO4 rebasaron los límites permisibles de la normatividad mexicana en alrededor de un tercio de los pozos. Aunque la mayoría de los sitos no excedieron los límites permisibles para nutrientes y metales pesados, algunos pozos mostraron niveles de NO2-, TP, SO4, y Pb preocupantemente altos, lo cual es un indicador de contaminación antropogénica. Todos los pozos presentaron contaminación por bacterias coliformes. La baja calidad del agua en algunas de las principales fuentes de abastecimiento del Estado se debe principalmente a la proliferación de basureros a cielo abierto y la deficiente red de alcantarillado, así como al cambio de uso del suelo dentro de la ZOC. Si no se implementan las medidas adecuadas, las actividades humanas continuaran extendiéndose dentro de estas áreas colocando a las fuentes de agua en un mayor riesgo de ser contaminadas.Â

Sustainable use of water resources should include the recognition that water has a social value, an environmental value and an economic value. The economic value of irrigation water should be expressed based on its price, which in turn is determined by the interplay of three factors: the cost of irrigation water (supply side), the willingness to pay for irrigation water (demand side) and public policies. This paper presents an analysis of the key methodological issues involved ineach of the above mentioned factors and how they influence the economic value of water

Sustainable use of water resources should include the recognition that water has a social value, an environmental value and an economic value. The economic value of irrigation water should be expressed based on its price, which in turn is determined by the interplay of three factors: the cost of irrigation water (supply side), the willingness to pay for irrigation water (demand side) and public policies. This paper presents an analysis of the key methodological issues involved ineach of the above mentioned factors and how they influence the economic value of water

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

Eichhornia crassipes es una planta de rápido crecimiento distribuida en casi todos los países tropicales, que puede tolerar condiciones de contaminación por metales o por eutrificación de cuerpos de aguas lénticos y lóticos. Esta planta se ha convertido en un problema ambiental; no obstante, ha despertado interés en el tratamiento de la contaminación por metales en suelos agrarios y cuerpos de agua. La toxicidad de los metales es un serio inconveniente en esta motivación, ya que influye en la capacidad de acumulación y la transmisión en la cadena trófica. En esta investigación se evaluó el comportamiento de las tasas de acumulación de cromo en la macrófita acuática Eichhornia crassipes, a concentraciones de 30, 60 y 90 mg/L, utilizando un diseño experimental aleatorio, con control y tres repeticiones por nivel. Los estudios llevados a cabo en acuarios de vidrio, evidenciaron sitios de acumulación de cromo en la planta, estableciéndose la cinética de acumulación.<br>Eichhornia crassipes é uma planta de rápido crescimento distribuídas em quase todos os países tropicais, que podem tolerar condições de contaminação por metáis ou de eutrofização das massas de águas lênticos e lóticos. Essa planta tornou-se um problema ambiental, no entanto, despertou o interesse no tratamento da poluição por metais em solos agrícolas e corpos d'água. A toxicidade dos metais é um problema serio com esse raciocínio, uma vez que afeta a capacidade de armazenamento e transmissão na cadeia alimentar. Neste estudo avaliou o comportamento das taxas de acúmulo de cromo em macrófitas aquáticas Eichhornia crassipes, em concentrações de 30, 60 e 90 mg/L, utilizando um delineamento inteiramente casualizado, com controle e três repetições por nível. Estudos realizados em aquários de vidro, apresentaram sítios de acumulação de crómio na planta, que institui a cinética de acumulação.<br>Eichhornia crassipes is a fast growing plant distributed in almost all tropical countries, which can tolerate conditions of metal contamination or eutrophication of bodies of lentic and lotic waters. This plant has become an environmental problem, however, has sparked interest in the treatment of metal pollution in agricultural soils and water bodies. The toxicity of metals is a serious problem with this reasoning, since it affects the storage capacity and transmission into the food chain. In this study we evaluated the behavior of the rates of accumulation of chromium in aquatic macrophyte Eichhornia crassipes, at concentrations of 30, 60 and 90 mg/L, using a randomized experimental design with control and three replicates per level. Studies carried out in glass aquaria, showed sites of accumulation of chromium in the plant, establishing the kinetics of accumulation.

Sánchez Medina, M.T. 2011. Efectividad del Nicosulfuron al cambiar el pH del agua. Proyecto especial de graduación del programa de Ingeniería Agronómica, Escuela Agrícola Panamericana, Zamorano. Honduras. 12 p. El uso de herbicidas es una de las prácticas principales para el manejo de malezas y está aumentando en los países en desarrollo. La calidad del agua es uno de los factores más importantes para la efectividad de los herbicidas. Uno de los aspectos importantes de la calidad del agua es el pH. El objetivo de este estudio fue evaluar la efectividad del herbicida Nicosulfuron (Accent® 75 WG) al modificar el pH del agua, usando dos dosis comerciales del mismo. Los pH utilizados fueron ácido, 3.3, y alcalino, 8.5. Las dosis utilizadas para cada pH fueron 50 y 70 g/ha. Como reguladores de pH se utilizó hidróxido de sodio y pH+®, como surfactante se utilizó ADSEE® 775. Se utilizó diseño de Bloques Completos al Azar (BCA) con cinco repeticiones. La efectividad del herbicida Nicosulfuron no aumentó al modificar el pH del agua, La dosis que tuvo más control sobre las malezas fue la de 70 g/ha. El efecto observado que el herbicida causó sobre las malezas fue una descoloración moderada, una marcada distorsión y recuperación esperada. También se realizó otro experimento para comparar el efecto de residualidad de dos lotes del herbicida, un lote vencido y un lote nuevo. El lote nuevo tuvo mayor efecto de residualidad que el lite vencido siendo 23% a los 7 días después de la aplicación y 16% a los 14 días después de la aplicación.

The shrimp farming cause significant environmental impacts due to high water consumption and effluent discharge, which worsen problems of sediment deposition and water pollution. This study aims to find an alternative for the use of shrimp farming effluent, and to mitigate the aforementioned impacts. The experiments were carried out in three phases, where the first dealt with the toxicity of the reused effluent on the post-larvae of shrimp, the second dealt with the short term mortality of the shrimps and the third dealt with the long-term survival and productivity of the shrimps along the entire growing cycle. The results show that the survival index is 42.1% when the shrimps are cultivated in shrimp farm effluent. However, most of the mortality occurred within the first week of the growing cycle. This indicates that a change in production strategy can increase productivity of the farm. | A carcinicultura causa impactos ambientais significativos devidos, sobremaneira, à elevada demanda de água e ao descarte de efluentes, agravando o problema de assoreamento e poluição dos mananciais. Este trabalho teve como objetivo buscar uma alternativa para o reaproveitamento do efluente da carcinicultura na própria atividade e assim mitigar os impactos causados. Os experimentos foram realizados em três etapas, a primeira relacionada à toxicidade, para as pós-larvas das águas de despesca, a segunda com a mortalidade das pós-larvas em curto prazo e a terceira relacionada com a sobrevivência em longo prazo e produtividade do camarão ao longo de um ciclo de engorda, utilizando-se água de despesca. Os resultados mostraram que o índice de sobrevivência é de 42,1% quando o camarão é cultivado em águas de despesca; no entanto, a maior mortalidade dos camarões ocorre principalmente na primeira semana do ciclo de engorda, indicando que uma mudança de estratégia na produção de camarão pode aumentar a produtividade da fazenda.