The risk of water stress

Water resources are under stress in many regions due to increasing demands and, in places, falling quality. Climate change has the potential to change the risks of water stress.1 The focus in this section is on strategic definitions of water stress, which are based on generalized indicators of the amount of water that is available and the demands on that resource. Operational definitions, on the other hand, are typically based on the reliability of the supply of appropriate quality water and are strongly determined by local conditions.

Season changes in water quality and Sargassum biomass in Southwest Australia

Sargassum C. Agardh is one of the most diverse genera of marine macro-algae and commonly inhabits shallow tropical and sub-tropical waters. This study aimed to investigate the effect of seasonality and the associated water quality changes on the distribution, canopy cover, mean thallus length and the biomass of Sargassum beds around Point Peron, Shoalwater Islands Marine Park, Southwest Australia. Samples of Sargassum and seawater were collected every three months from summer 2012 to summer 2014 from four different reef zones. A combination of in situ observations and WorldView-2 satellite remote-sensing images were used to map the spatial distribution of Sargassum beds and other associated benthic habitats. The results demonstrated a strong seasonal variation in the environmental parameters, canopy cover, mean thallus length, and biomass of Sargassum, which were significantly (P < 0.05) influenced by the nutrient concentration (PO43-, NO3-, NH4+) and rainfall. However, no variation in any studied parameter was observed among the four reef zones. The highest Sargassum biomass peaks occurred between late spring and early summer (from September to January). The results provide essential information to guide effective conservation and management, as well as sustainable utilisation of this coastal marine renewable resource.

Transit times – the link between hydrology and water quality at the catchment scale

In spite of trying to understand processes in the same spatial domain, the catchment hydrology and water quality scientific communities are relatively disconnected and so are their respective models. This is emphasized by an inadequate representation of transport processes, in both catchment-scale hydrological and water quality models. While many hydrological models at the catchment scale only account for pressure propagation and not for mass transfer, catchment scale water quality models are typically limited by overly simplistic representations of flow processes. With the objective of raising awareness for this issue and outlining potential ways forward we provide a non-technical overview of (1) the importance of hydrology-controlled transport through catchment systems as the link between hydrology and water quality; (2) the limitations of current generation catchment-scale hydrological and water quality models; (3) the concept of transit times as tools to quantify transport and (4) the benefits of transit time based formulations of solute transport for catchment-scale hydrological and water quality models. There is emerging evidence that an explicit formulation of transport processes, based on the concept of transit times has the potential to improve the understanding of the integrated system dynamics of catchments and to provide a stronger link between catchment-scale hydrological and water quality models.

Human Health Impacts of Contaminants Found in Local Drinking Water Supply

Many contaminants are currently unregulated by the government and do not have a set limit, known as the Maximum Contaminant Level, which is dictated by cost and the best available treatment technology. The Maximum Contaminant Level Goal, on the other hand, is based solely upon health considerations and is non-enforceable. In addition to being naturally occurring, contaminants may enter drinking water supplies through industrial sources, agricultural practices, urban pollution, sprawl, and water treatment byproducts. Exposure to these contaminants is not limited to ingestion and can also occur through dermal absorption and inhalation in the shower. Health risks for the general public include skin damage, increased risk of cancer, circulatory problems, and multiple toxicities. At low levels, these contaminants generally are not harmful in our drinking water. However, children, pregnant women, and people with compromised immune systems are more vulnerable to the health risks associated with these contaminants. Vulnerable peoples should take additional precautions with drinking water. This research project was conducted in order to learn more about our local drinking water and to characterize our exposure to contaminants. We hope to increase public awareness of water quality issues by educating the local residents about their drinking water in order to promote public health and minimize exposure to some of the contaminants contained within public water supplies.

Modeling Of District Metered Areas With Relatively High Leakage Rate. The Case Study Of Kalipoli’s DMA

The article reviews the modelling of District Metered Areas (DMAs) with relatively high leakage rate. As a generally recognised approach in modelling of leakage does not exist, modelling of leakage by enginners and other researchers usually takes place by dividing the whole leakage rate evenly to all available nodes of the model. In this article, a new methodology is proposed to determine the nodal leakage by using a hydraulic model. The proposed methodology takes into consideration the IWA water balance methodology, the Minimum Night Flow (MNF) analysis, the number of connections related to each node and the marerial of pipes. In addition, the model is illustrated by a real case study, as it was applied in Kalipoli’s DMA. Results show that the proposed model gives reliable results.

Topographical characteristics and evaluating water quality in watershed management

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

Electrical conductivity test in the evaluation of physiological quality in seeds of Zeyheria tuberculosa

The electrical conductivity test is still an excellent tool to evaluate the effect of seeds of various forest and agricultural species and recent studies have been conducted aiming at verifying its application in forest seeds. The objective of this study was to establish a specific methodology to test the electrical conductivity of forest seeds of Zeyheria tuberculosis. Four lots of seeds were used, which were submitted to the germination test, evaluating the percentage of germination, germination speed index and dry mass of seedlings. For the electrical conductivity test, five replicates of 20 seeds installed in three volumes of deionized water (75, 100 and 125 mL) were used and eight periods for seed imbibitions (2, 4, 6, 12, 18, 24, 48 and 72 hour) at 25 degrees C were allowed. The statistical design used was completely random; the comparison of means was performed by Tukey test at 5 % probability. Lot II showed higher germination percentage and speed. The electrical conductivity test allows discrimination of the same batch by the germination test under laboratory conditions. It was possible to separate the seed lot presenting better physiological quality (lot II) from among the other lots. It was recommended the use of 75 or 125 mL of deionized water at a temperature of 25 degrees C to perform the electrical conductivity test.

Changes in abiotic characteristics of water in the Paranapanema River and three lateral lagoons at mouth zone of the Jurumirim Reservoir during the flood period, São Paulo, Brazil

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

Genotoxicity assessment of water soluble fractions of biodiesel and its diesel blends using the Salmonella assay and the in vitro MicroFlow (R) kit (Litron) assay

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

Performance of the constructed wetland system for the treatment of water from the corumbataí river

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

Hydrochemical evaluation of the quality of some Brazilian waters

This investigation was carried out within the Parane sedimentary basin and neighbourhood in Brazil and involved the sampling of different water types with the purpose of evaluating its quality. Several methods were utilized for acquiring the hydrochemical data and a novel technique has been developed for evaluating the gross alpha and beta radioactivities in water, through a combined gamma-alpha spectrometry technique. The results obtained for the analyzed samples were compared with the guideline values established by the São Paulo State and Brazilian Health Ministry legislations for defining potable water standards and for the prevention and control of pollution in the environment. The hydrochemical data allowed evaluation of diverse problems related to the interaction between society and the environment such as sugarcane production and the releases associated with gas stations suppliers. The geogenic input of sulfate in groundwater was also identified. The established radiometric technique was properly calibrated and successfully applied to the analysis of different water types utilized for human consumption.

Optical modeling of aspherical lenses: a human eye study

We have been developing a computational code to project optical lenses, with low aberration effects. Our main interest is model the human eye, particularly, project special corrective lenses. As the lens shape is the focus of the optimization, we have coupled a ray tracing method with Monte Carlo techniques. The initial results indicated that the algorithm must be improved in terms of resolution and reliability.

Evaluation of water and sucrose diffusion coefficients in potato tissue during osmotic concentration

The water and sucrose effective diffusion coefficients behavior were studied in potato tubers immersed in aqueous sucrose solution, 50% (w/,A), at 27 degreesC. Water and sucrose concentration profiles were measured as function of the position for 3, 6 and 12 h of immersion. These were adjusted to a mathematical model for three components that take into account the bulk flow in a shrinking tissue and the concentration dependence of the diffusion coefficients.The binary effective coefficients were an order of magnitude lower than those for pure solutions of sucrose. These coefficients show an unusual concentration dependence. Analysis of these coefficients as functions of the concentration and position demonstrates that, cellular tissue promotes high resistance to diffusion in the tuber and also the elastic contraction of material influences the species diffusion. (C) 2003 Elsevier B.V. Ltd. All rights reserved.

Synthesis, spectroscopic characterization and molecular modeling of a tetranuclear platinum(II) complex with thiazolidine-4-carboxylic acid

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

Quantum chemical modeling of perovskite: An investigation of piezoelectricity in ferrite of yttrium

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)