This publication provides guidance to water-sector decision makers and planners on how to deal with the quality dimension of groundwater resources management in the World Bank's client countries. There is growing evidence of increasing pollution threats to groundwater and some well-documented cases of irreversible damage to important aquifers. This guide has been produced in the belief that groundwater pollution hazard assessment must become an essential part of environmental best practice for water supply utilities. The guide is particularly relevant for the World Bank's Latin American and Caribbean Region, where many countries have initiated major changes to modernize their institutional and legal framework for water resources management, but may not yet have considered groundwater at the same level as surface water, because of lack of awareness and knowledge of groundwater issues and policy options.

A by-product of Wastewater Treatment Stations is sewage sludge. By treatment and processing, the sludge is made suitable for rational and environmentally safe use in agriculture. The aim of this study was to assess the influence of different doses of limed sewage sludge (50 %) on clay dispersion in soil samples with different textures (clayey and medium). The study was conducted with soil samples collected from native forest, on a Red Latosol (Brazilian classification: Latossolo Vermelho distroférrico) loamy soil in Londrina (PR) and a Red-Yellow Latosol (BC: Latossolo Vermelho-Amarelo distrófico) medium texture soil in Jaguapitã (PR). Pots were filled with 3 kg of air-dried fine earth and kept in greenhouse. The experiment was arranged in a randomized block design with six treatments: T1 control, and treatments with limed sewage sludge (50 %) as follows: T2 (3 t ha-1), T3 (6 t ha-1), T4 (12 t ha-1), T5 (24 t ha-1) and T6 (48 t ha-1) and five replications. The incubation time was 180 days. At the end of this period, the pots were opened and two sub-samples per treatment collected to determine pH-H2O, pH KCl (1 mol L-1), organic matter content, water-dispersible clay, &#916;pH (pH KCl - pH-H2O) and estimated PZC (point of zero charge): PZC = 2 pH KCl - pH-H2O, as well as the mineralogy of the clay fraction, determined by X ray diffraction. The results showed no significant difference in the average values for water-dispersible clay between the control and the other treatments for the two soil samples studied and &#916;pH was the variable that correlated best with water-dispersible clay in both soils.<br>As Estações de Tratamento de Esgoto Sanitário (ETES) geram um subproduto (lodo de esgoto) que, quando tratado e processado, adquire características que permitem sua utilização agrícola de maneira racional e ambientalmente segura. Este trabalho objetivou avaliar a influência de diferentes doses de lodo de esgoto caleado (50 %) na dispersão de argilas em amostras de solos com diferentes texturas (muito argilosa e média). O estudo foi realizado com amostras de solos coletadas sob mata nativa, em Latossolo Vermelho distroférrico, textura muito argilosa, em Londrina (PR), e Latossolo Vermelho-Amarelo distrófico, textura media, em Jaguapitã (PR). Os vasos foram preenchidos com 3 kg de TFSA em casa de vegetação, em um delineamento de blocos ao acaso, com seis tratamentos - T1: controle; e os tratamentos com lodo de esgoto caleado (50%): T2 (3 t ha-1); T3 (6 t ha-1); T4 (12 t ha-1); T5 (24 t ha-1) e T6 (48 t ha-1), com cinco repetições. O tempo de incubação foi de 180 dias; após esse período, os vasos foram abertos e coletaram-se duas subamostras por tratamento, para determinar: pH-H2O, pH-KCl (1 mol L-1), teor de matéria orgânica, argila dispersa em água, &#916;pH (pH-KCl - pH-H2O) e o PCZ estimado: PCZ = 2 pH-KCl - pH-H2O, além da mineralogia da fração argila por difração de raios X. Os resultados permitiram concluir que não houve diferença significativa quanto aos teores médios de argila dispersa em água entre o controle e os outros tratamentos estudados para as duas amostras de solo; &#916;pH foi a variável que melhor se correlacionou com a argila dispersa em água nos dois solos.

Water quality monitoring is used to determine the impact of human activities on the environment. We evaluated water quality in the Água Boa stream, located within the municipality of Dourados, State of Mato Grosso do Sul, Brazil, by analyzing physico-chemical, chemical, and microbiological parameters, as well as chlorophyll concentrations. Five sets of water samples were collected between December 2012 and November 2013 from three locations within the stream. The results showed the presence of Escherichia coli and antibiotic-resistant Pseudomonas spp. strains and high concentrations of organic matter (total dissolved solids), inorganic species (Mg, Ca, and Fe), and agrochemical residues (thiamethoxam). The main stream water contaminants are derived from urban, industrial, and agricultural activities within the watershed. Given the presence of contaminants, it is important that such findings are disseminated in order to highlight the risks that contact with this water may pose to human health. To preserve the environment and improve site conditions, people would need to participate by demanding that normative national and international standards be respected and that the situation be supervised by the competent governmental agencies; this would make it possible to reverse or minimize contamination problems within the Água Boa stream.

Fil: Zerbatto, Mariel Guadalupe. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas; Argentina. | Se evaluaron los efectos de las modificaciones del pH de coagulación del proceso de potabilización en la remoción de materia orgánica natural, utilizando los coagulantes más comúnmente empleados en esta etapa y si estos cambios tienen algún impacto en la eliminación de quistes de Giardia intestinalis y ooquistes de Cryptosporidium spp. Se empleó la prueba de jarras (jar test) para simular los procesos de coagulación, floculación y sedimentación. Para analizar la remoción de materia orgánica natural y estos protozoos fueron seleccionados diferentes coagulantes (sulfato de aluminio, cloruro férrico y polihidroxicloruro de aluminio) y cuatro niveles de pH. Para la coagulación optimizada se ensayaron pH 5,0; 6,5; 8,0 y durante la coagulación convencional no se realizó ninguna modificación del pH. Se realizaron un total de 84 ensayos. Para la identificación y recuento de (oo)quistes de enteroparásitos se empleó el método de inmunofluorescencia con anticuerpos monoclonales. La materia orgánica natural se midió por absorción de UV a 254 nm. La remoción de materia orgánica natural, en la fuente de agua analizada para los tres coagulantes utilizados, fue semejante cuando se utilizó coagulación convencional. Similar conclusión se obtuvo durante coagulación optimizada a pH 5. Para cloruro férrico a pH 5, se halló que la reducción de materia orgánica natural fue superior en un 13,7 %, respecto a la coagulación convencional. Este valor fue mayor que los hallados para ambos coagulantes de aluminio La modificación de pH, no altera la eliminación de quistes de Giardia intestinalis y ooquistes de Cryptosporidium spp. | To evaluate, the effects of changes in pH coagulation treatment process in removing natural matter, using the most commonly used coagulant at this stage. To examine if these changes have an impact on the elimination of Giardia intestinalis cysts and Cryptosporidium spp oocysts. To simulate the process of coagulation, flocculation and sedimentation it was used the jar test. To analyze natural organic matter removal and enteroparasites (Cryptosporidium spp and Giardia intestinalis) 3 different coagulants were selected (aluminum, sulfate, ferric chloride and polyaluminum chloride) and four levels of pH. As regard enhanced coagulation pH 5,0; 6,5; 8,0 were tested and for conventional coagulation no modification of the pH was made. A total of 84 tests were carried out. For the identification and enumeration of (oo)cysts of enteroparasites, the immunoflourescence method with monoclonal antibodies was employed. The natural organic matter removal measurement was performed by UV absorption at 254 nm. The natural organic matter removal, to the water source tested, was similar for conventional coagulation and pH 5, it was verified with the three coagulants used. For ferric chloride at pH 5, it was found that the reduction of natural organic matter was higher by 13.7% compared to conventional coagulation. This value was higher than those found for both aluminum coagulants. The pH modification does not alter the removal of cysts of Giardia intestinalis and Cryptosporidium spp oocysts. | Universidad Nacional del Litoral

For every type of soil, the water retention curve is specific and depends on several soil features. This study was carried out to evaluate the influence of soil attributes on water retention in Red Latosol (Haplustox) and Red Latosol (Eutrustox) under different management and use systems. The use systems were: cotton, sugar-cane and woods. The granulometric composition, bulk density, organic matter, Fe2O3 and Al2O3 contents, as well as the water retention curve were determined for soil samples from different depths (0-10, 10-20, 20-30 and 30-40 cm). Organic matter did not demonstrate effective participation in water retention, while the attribute bulk density had the greatest positive correlation with water retention. Eutrustox soil presented greater water retention in all tensions and, in relation to Haplustox, the same capacity of available water (CAW). | A curva de retenção de água é específica a cada solo e depende de vários atributos do solo. Assim, objetivou-se avaliar a influência de atributos do solo na retenção de água em Latossolo Vermelho distrófico (LVd) e Latossolo Vermelho eutroférrico (LVef) sob diferentes sistemas de uso e manejo. Os sistemas de uso e manejo foram: algodão, cana-de-açúcar e mata. As amostras de solo foram coletadas nas profundidades de 0-10, 10-20, 20-30 e 30-40 cm, para determinar a composição granulométrica, densidade do solo, matéria orgânica, Fe2O3, Al2O3 e a curva de retenção de água. A matéria orgânica não demonstrou participação efetiva na retenção de água, e a densidade do solo revelou maior correlação positiva com a retenção de água. O LVef apresentou maior retenção de água em todas as tensões e a mesma capacidade de água disponível (CAD) em relação ao LVd.

The soil nematode fauna of five locations situated in Parque Nacional del Agua (PNA) in Costa Rica is characterized and analyzed. Four ecosystems were sampled in each location: primary (undisturbed) forest, secondary (naturally regenerated) forests, tree plantations (cleared and replanted with timber trees), and pastures (cleared of trees). Five soil samples of 100 g were analyzed in each location and ecosystem, resulting in a total of 100 samples. One hundred and thirty-one nematode genera were identified, and their abundance and biomass were estimated and analyzed by means of nonmetric multidimensional scaling (NMDS) and redundancy analysis (RDA). The observed nematode abundance was 1237 ± 520 specimens per soil sample for the whole survey, similar to previously reported from tropical soils. Dominance-diversity curves, based on nematode abundance, follow a similar ‘hollow curve’ pattern, with only 20 of the genera representing 84.6% of the total abundance, and only 12 of the genera representing 88% of the total biomass. Helicotylenchus, tylenchids, criconematids, Belondira, Longidorus, Xiphinema, Monotrichodorus, Prismatolaimus and Steinernema are important in the assemblages due their abundance or biomass in the different samples. Monotrichodorus and Discocriconemella appear related to undisturbed ecosystems, and they could have potential as disturbance indicators. Biomass-based dominance-diversity curves have similar qualitative and quantitative behavior to those observed in abundance distribution, but the dorylaims, Aporcelinus and Aporcelaimoides, which represented only the 0.35% of the abundance, having a major part of the total biomass (4.33%). NMDS analysis segregated locations into two groups, sampled sites were arranged according to the life zone where they belong. Ecosystems were segregated into natural ecosystems and plantations but having overlapping zones. Whereas RDA analysis indicated that organic matter and Cu are the most relevant edaphic variables for explaining the distribution of nematode assemblages, however few genera appear important in the ordination, Mesocriconema, Longidorus, Xiphinema and Belondira between them.

Abstract In this study, we made a review about carbon stocks and fluxes in Mexican freshwater wetlands. Data for carbon storage in roots, soil and biomass have been reported for marshes, forested wetlands and flooded grasslands in southeast Mexico: Veracruz, Chiapas and Yucatan. The largest carbon stock in freshwater wetlands is in the soil (150 Mg C ha-1 a 650 Mg C ha-1) and the forested wetlands showed the highest values. The carbon stock in the biomass ranges from 10 Mg C ha-1 to 162 Mg C ha-1, and forested wetlands showed the highest values. Carbon fluxes measured as litter fall have been reported for forested wetlands in Veracruz (6 Mg C ha-1 year-1 a 9 Mg C ha-1 year-1) only. Methane and carbon dioxide fluxes ranged from 0.01 mg C m-2 d-1 to 1244 mg C m-2 d-1, and 0.009 g C m-2 d-1 to 11 g C m-2 d-1 respectively for Veracruz and Tabasco wetlands. Such carbon fluxes increased up to ten times, when wetlands are transformed to grasslands. It is concluded that the number of publications and study sites on carbon dynamics in Mexican freshwater wetlands is still very small. Therefore, it is necessary to increase the research in this area and enact laws that protect these important carbon sinks. | Resumen Este trabajo hace una revisión bibliográfica sobre los almacenes y flujos de carbono en humedales de agua dulce en México. Se encontraron datos sobre almacenes de carbono en suelo, biomasa aérea y raíces en humedales herbáceos (popales, tulares y carrizales), humedales arbóreos (selvas inundables y palmares) y en humedales transformados en potreros que aún se inundan, para tres estados del sureste mexicano: Veracruz, Yucatán y Chiapas. El mayor almacén de carbono se ha registrado para el suelo de las selvas inundables (150 Mg C ha-1 a 650 Mg C ha-1). Los almacenes de carbono en la biomasa área de las selvas inundables fueron de 10 Mg C ha-1 a 162 Mg C ha-1, siendo también los valores más altos. Con respecto a los flujos de carbono medidos como caída de hojarasca en selvas inundables, solo se encontraron datos para Veracruz (6 Mg C ha-1 año-1 a 9 Mg C ha-1 año-1). Los flujos de metano y bióxido de carbono estuvieron en el intervalo de 0.01 mg C m-2 d-1 a 1244 mg C m-2 d-1 y 0.009 g C m-2 d-1 a 11 g C m-2 d-1 respectivamente, para Veracruz y Tabasco, y dichas emisiones aumentan hasta 10 veces en humedales transformados en potreros. Se concluye que aún son muy pocas las publicaciones y pocos los sitios estudiados sobre la dinámica del carbono en humedales de agua dulce, por lo que hay que incrementar la investigación en esta línea, ya que los humedales son importantes sumideros de carbono y es necesaria una legislación que proteja las reservas de carbono en estos ecosistemas.

El principio del lagunado no es otro que el aprovechamiento del ciclo de la materia orgánica en el agua, generada por las excretas de los peces, restos de pienso, etc. en su discurrir por un circuito hidrodinámico diseñado al efecto, aprovechando los diferentes nichos biológicos de los sucesivos "consumidores" de esa materia orgánica "contaminantes"; descargando sucesivamente el agua efluente de su contenido orgánico y bacteriano y convirtiéndola de nuevo en agua influente con la calidad para reincorporarla al sistema de produccion