Stream water quality is controlled by the interaction of natural and anthropogenic factors over a range of temporal and spatial scales. Among these anthropogenic factors, land cover changes at catchment scale can affect stream water quality. This work aims to evaluate the influence of land use and seasonality on stream water quality in a representative tropical headwater catchment named as Córrego Água Limpa (Sao Paulo, Brasil), which is highly influenced by intensive agricultural activities and urban areas. Two systematic sampling approach campaigns were implemented with six sampling points along the stream of the headwater catchment to evaluate water quality during the rainy and dry seasons. Three replicates were collected at each sampling point in 2011. Electrical conductivity, nitrates, nitrites, sodium superoxide, Chemical Oxygen Demand (DQO), colour, turbidity, suspended solids, soluble solids and total solids were measured. Water quality parameters differed among sampling points, being lower at the headwater sampling point (0m above sea level), and then progressively higher until the last downstream sampling point (2500m above sea level). For the dry season, the mean discharge was 39.5ls⁻¹ (from April to September) whereas 113.0ls⁻¹ were averaged during the rainy season (from October to March). In addition, significant temporal and spatial differences were observed (P<0.05) for the fourteen parameters during the rainy and dry period. The study enhance significant relationships among land use and water quality and its temporal effect, showing seasonal differences between the land use and water quality connection, highlighting the importance of multiple spatial and temporal scales for understanding the impacts of human activities on catchment ecosystem services.

Se exponen algunos criterios sobre la calidad del agua para riego en lo que respecta a salinidad, sodicidad y toxicidad. Se señalan los parámetros a determinar cuando se evalúa la calidad de agua que incluyen Ph, contenido total de sales disueltas. Contenido de K, Cl, Na, B, índice de Mg, relación de adsorción de Na, Carbonato de Sodio residual y dureza. Se indican las normas de calidad de aguas de riego y su clasificació

Se exponen algunos criterios sobre la calidad del agua para riego en lo que respecta a salinidad, sodicidad y toxicidad. Se senalan los parametros a determinar cuando se evalua la calidad de agua que incluyen Ph, contenido total de sales disueltas. Contenido de K, Cl, Na, B, indice de Mg, relacion de adsorcion de Na, Carbonato de Sodio residual y dureza. Se indican las normas de calidad de aguas de riego y su clasificacio.

A reutilização do efluente de esgoto tratado para suprir a falta de fontes d'água para irrigação tem sido de grande interesse para a agricultura e o uso desta prática, se não regulamentado, pode acarretar em mudanças no comportamento físico e químico do solo. Objetivou-se, neste trabalho, a avaliação das alterações dos atributos físico-químicos de um Latossolo Vermelho amarelo, após a aplicação da água de reúso proveniente de uma estação de tratamento de efluentes por leitos cultivados. Um experimento em coluna de solo foi realizado em laboratório; 15 L de água destilada lhe foram aplicados e, logo após, mais 15 L de água de reúso e, a cada 5 L, foi coletada amostra da água lixiviada para análises. Os resultados mostraram, após a aplicação no solo, da água de reúso, redução de nitrato, potássio e valores da condutividade hidráulica saturada e aumento das concentrações de sódio, ferro, manganês, zinco e condutividade elétrica. Pode-se concluir, desta forma, que a utilização de água de reúso para fins agronômicos deve ser de forma racional, monitorando-se principalmente a elevação do teor do íon sódio.<br>The reuse of treated sewage effluent to water bodies to supply water for irrigation has been of great advantage to agriculture, and the use if not regimented could bring changes in physical and chemical properties of soil. This paper aimed the evaluation of the physical and chemical properties alteration of a Red-yellow Latosol after the application of reuse water from an effluent treatment station of wetlands. The experiment was accomplished in laboratory using a soil column. First, 15 L of distilled water were applied in the soil column and after 15 L of reuse water and at interval of 5 L of water a sample was collected for analysis. The results showed decrease of nitrate, potassium and saturated hydraulic conductivity values and an increase in sodium, iron, manganese, zinc and electrical conductivity of the soil after water application. In this way, it may be concluded that the use of waste water for agronomic activities must be used in a rational way, mainly checking the elevation of sodium.

The objective of this study was to evaluate the inorganic parameters in the water of the Texcoco river. Sampling took place at 10 sites along the watershed (between 2500 and 2240 m above sea level) during the four seasons of the year for three years, with repetitions. The diagnostic parameters and methods used were, for potassium, sodium, magnesium, and calcium, the internal method MI-AM-011 (atomic absorption); phosphates with MI-FQUAR-012, chlorides NMX-AA-073-1981, electrical conductivity and nitrogen of nitrates NOM-AA-93-1984 and NOM-AA-79-1986, pH NMX-AA-08-1980. The three-year average concentrations of calcium, magnesium, potassium, sodium, chlorine, nitrates, and electrical conductivity were low. However, the concentrations of sodium and electrical conductivity were close to medium quality. The concentrations of sodium during Years 2 and 3 were classified as medium. The concentration of phosphates was high. Electrical conductivity during Years 1 and 3 were classified as medium. The concentrations of sodium and electrical conductivity in Seasons 1 and 4 grade a medium quality. The concentration of phosphates during the four seasons and three years were classified as high. Variability of cations and anions at different times of the year was an almost generalized behavior and statistically significant.

Aim: To study the effects of drinking 0.5 L of two sodium-rich bicarbonated mineral waters (BMW-1 and 2), with a standard meal, on postprandial insulin and glucose changes. And to determine, if the effects vary depending on insulin resistance, measured by homeostasis model assessment (HOMA). Methods: In a 3-way randomized crossover study, 18 healthy postmenopausal women consumed two sodiumrich BMWs and a low-mineral water (LMW) with a standard fat-rich meal. Fasting and postprandial blood samples were taken at 30, 60 and 120 min. Serum glucose, insulin, cholesterol and triacylglycerols were determined. Insulin resistance was estimated by HOMA and insulin sensitivity was calculated by quantitative insulin sensitivity check index (QUICKY). Results: Glucose levels did not change. HOMA and QUICKY values were highly inversely correlated (r = -1,000; p < 0.0001). Insulin concentrations showed a significant time effect (p < 0.0001) and a significant water x time interaction (p < 0.021). At 120 min insulin levels with BMW-1 were significantly lower than with LMW (p = 0.022). Postprandial insulin concentrations showed significantly different patterns of mineral water intake depending on HOMA n-tiles (p = 0.016). Conclusion: Results suggests an increase in insulin sensitivity after BMWs consumption. This effect is more marked in the women, who have higher HOMA values. These waters should be considered part of a healthy diet in order to prevent insulin resistance and cardiovascular disease.<br>Objetivo: Estudiar los efectos de la ingesta de 0.5L de dos aguas minerales bicarbonatadas ricas en sodio (BMW-1 y 2), junto con una comida estándar, sobre los cambios en la insulina y la glucosa postprandial; y determinar si los posibles efectos varían en función de la resistencia a la insulina evaluada a través del modelo homeostático (HOMA). Métodos: 18 mujeres postmenopáusicas sanas participaron en un estudio triple cruzado aleatorizado, en el que bebieron 2 aguas minerales bicarbonatadas ricas en sodio (BMW-1 y 2) y un agua mineral débil (LMW) junto con una comida estándar rica en grasa. Se tomaron muestras de sangre en ayunas y postprandiales a los 30, 60 y 120 min. Se determinó glucosa, insulina, colesterol y triglicéridos en suero. La resistencia a la insulina fue estimada a través del HOMA y la sensibilidad a la insulina se calculó mediante el índice de sensibilidad cuantitativa a la insulina (QUICKY). Resultados: Los niveles de glucosa no presentaron cambios. Los valores de HOMA y QUICKY presentaron una fuerte correlación inversa (r = -1,000; p < 0,0001). Las concentraciones de insulina mostraron un efecto significativo en el tiempo (p < 0,0001) y una interacción agua x tiempo significativa (p < 0,021). A los 120 min los niveles de insulina fueron significativamente inferiores con BMW1 respecto a LMW (p = 0,022). Las concentraciones postprandiales de insulina mostraron patrones significativamente distintos según el tipo de agua que se bebía dependiendo de los n-tiles del HOMA (p = 0,016). Conclusión: Los resultados sugieren un aumento de la sensibilidad a la insulina tras el consumo de las dos aguas minerales bicarbonatadas ricas en sodio. Este efecto es más marcado en las mujeres que tienen unos valores de HOMA más altos. Este tipo de aguas deberían ser consideradas como parte de una dieta saludable con objeto de prevenir la resistencia a la insulina y las enfermedades cardiovasculares.

The reuse of treated sewage effluent to water bodies to supply water for irrigation has been of great advantage to agriculture, and the use if not regimented could bring changes in physical and chemical properties of soil. This paper aimed the evaluation of the physical and chemical properties alteration of a Red-yellow Latosol after the application of reuse water from an effluent treatment station of wetlands. The experiment was accomplished in laboratory using a soil column. First, 15 L of distilled water were applied in the soil column and after 15 L of reuse water and at interval of 5 L of water a sample was collected for analysis. The results showed decrease of nitrate, potassium and saturated hydraulic conductivity values and an increase in sodium, iron, manganese, zinc and electrical conductivity of the soil after water application. In this way, it may be concluded that the use of waste water for agronomic activities must be used in a rational way, mainly checking the elevation of sodium. | A reutilização do efluente de esgoto tratado para suprir a falta de fontes d'água para irrigação tem sido de grande interesse para a agricultura e o uso desta prática, se não regulamentado, pode acarretar em mudanças no comportamento físico e químico do solo. Objetivou-se, neste trabalho, a avaliação das alterações dos atributos físico-químicos de um Latossolo Vermelho amarelo, após a aplicação da água de reúso proveniente de uma estação de tratamento de efluentes por leitos cultivados. Um experimento em coluna de solo foi realizado em laboratório; 15 L de água destilada lhe foram aplicados e, logo após, mais 15 L de água de reúso e, a cada 5 L, foi coletada amostra da água lixiviada para análises. Os resultados mostraram, após a aplicação no solo, da água de reúso, redução de nitrato, potássio e valores da condutividade hidráulica saturada e aumento das concentrações de sódio, ferro, manganês, zinco e condutividade elétrica. Pode-se concluir, desta forma, que a utilização de água de reúso para fins agronômicos deve ser de forma racional, monitorando-se principalmente a elevação do teor do íon sódio.

En este trabajo se pretende determinar la efectividad de las sales de sodio, el curado, el agua caliente y la combinación de estos tratamientos como alternativas en el control de Penicillium digitatum Sacc.

En experimentos realizados en invernadero, algunos autores han mostrado que el sulfato amónico origina mayor acidez y salinidad que otras fuentes de nitrógeno. Los inhibidores de la nitrificación (NI) tienden a acumular amonio en los suelos al retardar la oxidación a nitratos. Este amonio acumulado también tendría un efecto sobre la salinidad del suelo. Consecuentemente, el objetivo de este trabajo fue evaluar la salinización del suelo y agua de drenaje, debido al efecto asociado a la adición de NI, dimetilpirazolfosfato (DMPP) y diciandiamida (DCD), al fertilizante nitro-sulfato amónico (ASN). Este experimento fue realizado en condiciones de campo con un cultivo de maíz irrigado. Se midieron el drenaje y la concentración de Na durante dos periodos de cultivo (2006 y 2007) y también se determinó el sodio lixiviado. Los tratamientos con NI (DCD y DMPP) dieron lugar a mayores concentraciones de Na en la solución del suelo y consecuentemente mayores cantidades de Na lixiviado (en 2007, ASN-DCD 1.292 kg Na/ha, ASN-DMPP 1.019 kg Na/ha). Con el tratamiento de ASN sin inhibidor, también aumentó la concentración en el suelo y el Na lixiviado (en 2007, 928 y 597 kg Na/ha para ASN y el control, respectivamente). El aumento de la concentración de amonio en el suelo, debido a los tratamientos con NI, podría deberse al desplazamiento de los iones Na del complejo de cambio, mediante un proceso que finalmente conduce a un aumento de la salinidad. Los tratamientos que incluyen amonio en la formulación del fertilizante junto a un NI originaron un mayor grado de salinización debido al amonio procedente del fertilizante y al amonio acumulado procedente de la inhibición de la nitrificación. | In experiments carried out in greenhouses, some authors have shown that ammonium sulphate induces greater soil acidity and salinity than other sources of N. Moreover, nitrification inhibitors (NI) tend to cause ammonium to accumulate in soil by retarding its oxidation to nitrate. This accumulated ammonium would also have an effect on soil salinity. Consequently, the aim of this paper was to evaluate the soil and leaching water salinization effects associated with adding NI, dicyandiamide (DCD) and dimethylpyrazole-phosphate (DMPP) to ammonium sulphate nitrate (ASN) fertilizer. This experiment was carried out in the field with an irrigated maize crop. Drainage and Na concentration were measured during both seasons (2006 and 2007) and leached Na was determined. The treatments with NI (DCD and DMPP) were associated with greater Na concentrations in soil solutions and consequently higher rates of Na leaching (in 2007, ASN-DCD 1,292 kg Na/ha, ASN-DMPP 1,019 kg Na/ha). A treatment involving only ASN also increased the Na concentration in soil and the amount of Na leached in relation to the Control (in 2007, ASN 928 kg Na/ha and control 587 kg Na/ha). The increase in the ammonium concentration in the soil due to the NI treatments could have been the result of the displacement of Na ions from the soil exchange complex through a process which finally led to an increase in soil salinity. Treatments including ammonium fertilizer formulated with NI produced a greater degree of soil salinization due to the presence of ammonium from the fertilizer and accumulated ammonium from the nitrification inhibition.