Lietuvoje kaip ir daugelyje pasaulio šalių dedama daug pastangų, kad vandenų tarša mažėtų. Pagal valstybinio monitoringo duomenis nustatyta, kad Lietuvos upėse vis dar išlieka didelės biogeninių medžiagų koncentracijos. Vandens tarša yra viena iš pagrindinių ES aplinkosaugos problemų. Norint išsiaiškinti pagrindines vandens taršos problemas, būtina atlikti nagrinėjamos upės vandens kokybės parametrų matavimus. Tam tikslui nuo 2010-11-06 iki 2013-05-07 buvo atliekami vandens kokybės tyrimai, kurių metu buvo fiksuojami šie parametrai: vandens lygis, ištirpusio deguonies koncentracijos, aktyvi vandens reakcija (pH), bendrosios mineralizacijos, elektrinio laidžio, nitratų ir vandens temperatūros kaita. Vandens kokybės parametrai matuoti aukščiau ir žemiau Akademijos tvenkinio, kuris susidarė 1968 m. ant Dotnuvėlės upės ties Akademijos gyvenviete. Pagal minėtus duomenis buvo nustatyta vandens kokybė atskiruose Dotnuvėlės ir jos intako Kačiupio upių taškuose. Atlikus tyrimą buvo nustatyta, kad Akademijos tvenkinys sąlygoja nitratų pasiskirstymą upėje, t. y. pastebėtas nedidelis nitratų padidėjimas upėje žemiau tvenkinio. Nustatyta, kad bendroji mineralizacija rudenį didėjo, žiemos metu svyravo, o pavasarį mažėjo. Pagal ištirpusio deguonies kiekį visose matavimo stotyse vanduo atitiko labai blogą, blogą, vidutinę, gerą arba labai gerą būklę. Vandens lygis Akademijos tvenkinyje tiriamuoju laikotarpiu svyravo 0−19 cm ribose stoties „O“ atskaitos atžvilgiu. Kitų išmatuotų vandens... [toliau žr. visą tekstą] / In Lithuania, as well as in other countries of the world, great efforts are made to reduce water pollution. According to the national monitoring data, there is still a high concentration of biogenic substance in Lithuanian rivers. Water pollution problem is one of the key EU environmental issues. In order to find out the main water pollution problems, it is necessary to conduct the measurements of water quality parameters of the investigated River. For this purpose, from 06/11/2010 to 07/05/2013 water quality measurements were carried out, during which values of the following parameters were recorded: water level fluctuations, dissolved oxygen concentration, pH, total dissolved solids, the variation of nitrates and water temperature. Water quality parameters were measured upstream and downstream the pond at Akademija settlement. In accordance with the given data, water quality was identified in several points of Dotnuvėlė and Kačiupio rivers. The research revealed that the pond of Akademija determines nitrate distribution in the river, i.e. a slight nitrate increase was observed in the river below the pond. It was disclosed that in autumn total dissolved solids increased, in winter the concentration varied and it decreased in spring. According to the amount of dissolved oxygen at all measurement stations, water corresponded to a poor, extremely poor, moderate, good or extremely good condition. During the research period, water level in the pond of Akademija ranged from 0-19... [to full text]

<p>This research investigated the nature, source and the spatial variation of the salinity of the water used for irrigation in the urban farming area of Philippi, which lies in the Cape Flats region of the Cape Town Metropolitan Area, South Africa. The irrigation water is mainly drawn from the Cape Flats aquifer, and pumped into ponds for eventual crop irrigation. Water samples were collected in summer and in winter from fifteen selected sites using standard water sampling procedures. Each site consisted of one borehole and one pond. The samples were routinely analyzed for salinity levels, and concentrations of major and minor ions. From the same boreholes and ponds, water was sampled in summer for isotope analysis to assess effects of evaporation on the water quality and salinity. Descriptive statistics were used to display the variation in range of specific ions in order to compare them with the recommended ranges. Geographical Information Systems analysis described the spatial distribution of the salinity across the study area, and hydrogeochemical analysis characterized the various waters and detected similarities between the water samples in the study area and other waters found in the Cape Flats region. In addition, the US salinity diagram classification of irrigation water developed by Richards (1954) was used to assess the current suitability of groundwater and pond water samples collected during the entire sampling period for irrigation activities. The research indicated that the concentrations of some ions such as chloride, nitrate, potassium and sodium exceeded in places in the study area, the target range values set by the Department of Water Affairs and Forestry (DWAF, 1996) and the Food and Agriculture Organization (Ayers and Westcot, 1985). It revealed that borehole and pond water were mostly brackish across the area regarding their total dissolved salts content, and fresh water was only found in the middle part of the study area. The research found that sea water does not intrude into the aquifer of the study area, and the accumulation of salts in groundwater and soil in the study area is mainly due to the agricultural activities and partially due to the natural movement of water through the geological formation of the Cape Flats region. The conceptual model of the occurrence of the salinization process supported these findings. From this investigation it is understood that the groundwater and pond water in the study area were generally suitable for irrigation purposes but they have to be used with caution as the vegetables are classified as sensitive and moderately sensitive to salt according to DWAF Irrigation water guidelines (1996). The quality of these waters was mainly affected by the land use activities.</p>

Many brackish water aquaculture ventures in Australia and overseas have established ponds in coastal regions with acid sulfate soils (ASS). Acid sulphate soils are known to leach relatively high concentrations of metals, acid (metal and H+ ion) and sulfur, however very little is known about how these leached elements affect the water quality of aquaculture ponds. The main objective of this thesis was to describe the hydrochemical processes controlling the water chemistry in the water column and sediment pore water in the studied aquaculture ponds over time and space. Water samples providing the spatio-temporal data were collected from the ponds with the use of adapted sampling methods commonly used in the groundwater environment. A transect of five nested piesometers was installed in two prawn ponds at Pimpama, south east Queensland, Australia. Each piesometer nest contained a multilevel with eight outtakes, a mini ?? horizontal, and a slotted piesometer. Water samples were collected from each nested piesometer on a bi-monthly basis over the prawn-growing season. The unstable elements and water quality variables (pH, Eh, DO, EC, water temperature) were measured in the field. Stable elements were analysed in the laboratory using ICP-OES and ICP-MS. Soil samples were collected at the end of the season for elemental analysis. A number of key sediment/water interactions and processes such as precipitation/dissolution reactions, oxidation-reduction reactions, photosynthesis, adsorption and seawater buffering were identified as important controls on pond water conditions. This is the first study to provide detailed hydrochemcial analysis of the pond water over time and space and aided in identifying that even shallow water bodies can be chemically heterogeneous. Analysis of the water and sediment highlighted the selection of metals that can be associated with ASS and that are mobilised from pond sediments under certain chemical conditions. In Pond 7 Al, As, Ni and Zn concentrations were generally higher at the beginning of the grow-out season. Variability of the metal concentration was observed between the water column (0 ?? 1500 mm) and the pore-water (0 - -1000 mm). The highest concentration of Al (1044 ??g/L) and Zn (104 ??g/L) were sampled in the water column (approximately 400 mm from the surface of the pond). The highest concentration of As (130 ??g/L) and Ni (73 ??g/L) were sampled in the pore water sediment (associated with ASS). Elevated Mn and Fe2+ concentrations were also associated with the sediment pore water. The highest concentrations of Mn and Fe2+ were 4717 ??g/L and 5100 ??g/L respectively. In Pond 10, Ni concentrations (167 ??g/L) were the highest at the beginning of the grow-out season. However, As (97 ??g/L), Al (234 ??g/L) and Zn (308 ??g/L) were most concentrated during the middle of the cycle. The highest mean concentrations of these elements are As (63 ??g/L), Al (91 ??g/L) and Zn (69 ??g/L) which are each associated with the sediment-water interface. These metals are integral in degrading the pond water quality and lead to a loss of beneficial algal blooms, a reduction in pond water pH, poor growth rates and high mortality in shrimp. It is also possible that the dissolved ions and precipitated compounds that are leached from the ASS are discharged into the adjacent coastal estuary of Moreton Bay. With knowledge obtained from this PhD study, effective management and treatment systems can be developed and implemented to minimise the impact of these soils on the pond system and the water discharging into natural coastal ecosystem.

Ecological communities along gradients of environmental stress are thought to be structured by trade-offs between resisting biotic interactions in physically benign habitats and successfully exploiting physically stressful habitats. However, these trade-offs are likely to be affected by the predictability of abiotic stressors, and variation in the strength of biotic interactions. I investigated community assembly and food web interactions in ponds across an unpredictable gradient of water inundation (pond permanence) in Canterbury, New Zealand. Pond community composition and species richness were strongly influenced by pond permanence. However, species in temporary ponds were a nested subset of generalists that were also found in permanent ponds, rather than a unique assemblage of temporary pond specialists. Subsequent experiments indicated predator impact decreased with pond permanence, partially due to the foraging suppression of predatory invertebrates in permanent ponds by fish. Weak predation in permanent ponds combined with unpredictable drying regimes likely selected for generalist traits, and resulted in community assembly being driven by a gradient of drying stress rather than trade-offs between biotic interactions and drying. Furthermore, predator impact increased over time in temporary ponds. In predictable snow-melt ponds in the Colorado Rocky Mountains, seasonal windows of weak predation were exploited by vulnerable species, leading to increased diversity within habitats. However in unpredictable systems like Canterbury, temporal increases in predation risk that depend on drying history are likely to increase variability in the spatial arrangement of suitable habitats for particular species. This should further favour the evolution of generalist traits and reduce the importance of trade-offs between predation and drying in the assembly of communities. Considering the predictability of disturbance regimes and the spatial and temporal variation in biotic interactions will greatly enhance understanding and management of communities in heterogeneous landscapes.

Thesis (M.P.E.)--Memorial University of Newfoundland, 1997. / Bibliography: leaf 79.

Thesis (Ph. D.)--Florida State University, 2006. / Advisor: Glen H. Doran, Florida State University, College of Arts and Sciences, Dept. of Anthropology. Title and description from dissertation home page (viewed June 13, 2006). Document formatted into pages; contains xii, 126 pages. Includes bibliographical references.

Made available in DSpace on 2014-06-11T19:32:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-07-01Bitstream added on 2014-06-13T20:24:18Z : No. of bitstreams: 1 suhet_mi_dr_jabo.pdf: 911264 bytes, checksum: 71199b02b3ed48730d7b117d1868bb6d (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação para o Desenvolvimento da UNESP (FUNDUNESP) / A criação intensiva de peixes tem se tornado popular, mas a dependência de arraçoamento pode enriquecer o ambiente com nutrientes, comprometendo a qualidade da água e predispondo os peixes a doenças. Streptococcus e Aeromonas são bactérias que acometem peixe em criações intensivas, podendo ocasionar mortalidade. Nesse sentido, o presente trabalho objetivou avaliar a influência de uma criação de tilápias do nilo em tanques-rede nos parâmetros de qualidade da água e na ocorrência de Streptococcus spp. e Aeromonas spp. na água e nos peixes em uma lagoa na região Sudeste do Brasil. Foram definidos para as amostragens dois locais, a lagoa, para coleta de água e os tanques-rede, para coleta de água e peixes e dois períodos, seco e chuvoso. Os dados obtidos da qualidade da água foram avaliados por indicadores estabelecidos na Resolução Conama nº 357, para corpos de água doce de classe 2. A presença de Streptococcus spp. e Aeromonas spp. foi avaliada por identificação fenotípica e a identificação das espécies, por provas bioquímicas. Isolados foram avaliados para produção de hemolisina utilizando ágar sangue e teste de resistência a antimicrobianos conforme o método de difusão de discos. A atividade de criação intensiva de peixes aumentou a concentração de fósforo total da água no período seco, ocorrência de Streptococcus spp. no ambiente e a população de Aeromonas spp. na superfície dos peixes. No período chuvoso, houve maior isolamento das espécies potencialmente patogênicas, Aeromonas hydrophila na superfície e no rim dos peixes, A. caviae, A. sobria, A veronii, A. jandaei e Streptococcus agalactiae na superfície dos peixes, quando também ocorreu aumento da concentração de N-amoniacal e depleção acentuada da concentração de oxigênio dissolvido na água, e isso pode ter sido a causa da mortalidade de peixes nos tanquesrede... / Intensive fish farming is becoming more and more popular, but dependency on ration feeding increases nutrient load of the water, affects its quality and predisposes fish to diseases. Streptococcus and Aeromonas are bacteria that can affect fish in intensive farms and cause mortality. This study aims at evaluating the impact of a nile tilapia net-cage farm on the water quality parameters and the occurrence of Streptococcus spp. and Aeromonas spp. in the water and on the fish, in a pond in Southeastern Brazil. Two sampling sites were defined, one in the pond and another in the net cages to collect water, and water and fish, respectively. Sampling took place during two periods, dry and rainy. Water quality data were analyzed according to standards set by Conama resolution nº 357, for freshwater bodies class 2. Streptococcus spp. and Aeromonas spp. were determined by phenotypic and species identification using biochemical tests. Isolates were evaluated for hemolysin production using blood agar and antimicrobial resistance test according to disk diffusion method. Intensive fish farming increased the amount of phosphorus in water, Streptococcus spp. occurrence in the environment and Aeromonas spp. population on fish surface as well, during dry periods. During the rainy season, more potentially pathogenic bacteria were isolated such as, Aeromonas hydrophila on fish surface and kidneys, A. caviae, A. sobria, A veronii, A. jandaei and Streptococcus agalactiae on fish surface. An increase of N-ammoniacal was also observed together with severe depletion of dissolved oxygen, which may have caused fish mortality in the net-cages. Production of b-hemolysis was greater for aeromonas species isolated from the water and fish kidneys, while for streptococci it was higher in isolates from fish surface. The species Aeromonas veronii, A. hydrophila, A. jandaei, A. sobria A. caviae and Streptococcus agalactiae... (Complete abstract click electronic access below)

The safety case for a proposed geological disposal facility (GDF) for radioactive wastes relies upon a series of engineered and natural barrier systems to limit the migration of harmful radionuclides into the geosphere over geological timescales. Natural minerals, dominantly phyllosilicates, are expected to be the most reactive components of both the host rock and the clay-based backfill surrounding the highly radioactive waste canisters for as long as 100,000 years. Upon eventual canister degradation, alpha-emitting radionuclides will leach into the backfill material (and eventually beyond) and the constituent mineral systems will accumulate radiation damage upon radionuclide uptake and/or surface precipitation. The following study is an assessment of the structural and chemical effects caused by alpha-particle bombardment of silicate minerals, as proxies for the radiation stability of natural materials present in the near and far field of a GDF.Microscopy and spectroscopy studies from naturally occurring radiation damage accumulated in silicates over geological timescales (forming distinct 'radiohaloes') have shown that both alpha-particle and alpha-recoil bombardment results in altered unit cell dimensions caused by the accumulation of point (Frenkel) defects. In the example of highly damaged biotite, structural breakdown through the reorientation of discrete lattice crystallites was observed; the variability of the interlayer spacing within these regions reveal the potential for damaged mica to adopt the structure of phyllosilicate breakdown products over geological time. Controlled alpha-particle irradiation using the Dalton Cumbrian Facility's 5 MV tandem pelletron ion accelerator, combined with microfocus spectroscopy analysis has revealed the mechanisms of high fluence alpha-radiation damage across 2:1 phyllosilicate minerals (biotite and chlorite); reducing the layered structures into a series of loosely connected domains of alternating lattice expansion and collapse. Radiation induced Fe redox changes have been revealed, with Fe reduction apparent at relatively low alpha-particle doses, giving way to Fe oxidation at high doses. A 'redox gradient', based on alpha-particle energy deposition through a silicate structure has therefore been proposed. In addition, the increase in 'edge' sites generated by structural deformation has been shown to be favourable for the adsorption of the Se(IV) oxyanion to the mica surface. Comprising a body of additional work, a core sample has been extracted from a spent nuclear fuel pond wall at the decommissioned Hunterston A nuclear power station and the radioactive contamination on the painted core surface has been analysed by microfocus spectroscopy. The contaminant radiostrontium has been shown to be associated with the Ti rich pigment in the surface paint, resulting in a 'patchy' accumulation of radioactivity at the core surface. In addition, inert Cs reactivity experiments using the underlying concrete have shown that Cs is preferentially uptaken by phyllosilicates within the altered mafic clasts used in the concrete aggregate.

Magister Scientiae - MSc (Biotechnology) / The treatment of mine water at the eMalahleni Water Reclamation Plant (EWRP) results in the production of large volumes of brine. Different brine management methods have been applied to dispose the brine but the evaporation pond method is regarded as the cheaper, most effective and less laborious method for brine disposal. Brine wastewater is pumped into the pond where it evaporates resulting in the mixture of salts. The rate at which evaporation occurs is influenced by many factors such as temperature, salinity, humidity and wind. Due to high salinities in brine the EWRP is currently experiencing a challenge with low evaporation rate. Here, a comparative study was done to determine the efficiency of using a chemical and a biological approach to enhance the evaporation rate of reject brine. The chemical approach involved the addition of various concentrations of methylene blue dye (100 to 300 ppm with 50 ppm increments) to 1L volumes of brine, and measuring the evaporation rate. On the other hand, the biological approach involved the isolation of pigmented halophilic bacteria from eMalahleni brine and Cerebos salt samples. Isolated bacterial strains were characterised based on their morphology, biochemical and salt tolerance characteristics. Furthermore, the strains were identified using 16S rRNA gene sequence analysis. Among the isolated halophilic bacterial strains, EP-3, an Arthobacter agilis isolated from the eMalahleni brine produced a darker pigment compared to the other strains. Therefore, EP-3 was evaluated for its effect on the evaporation of brine using a culture inoculum or the addition pigment extracted from an EP-3 culture. The addition of MB above 100 ppm overcame the effect of salt precipitation and resulted in higher evaporation (41%) rate. Addition of pigmented bacteria or bacterial extracted pigment to the brine respectively resulted in 18% and 24% increase in the evaporation rate.

The revitalization plan was made for Kubňů Černá pond in Třeboň basin, Czech Republic. The detailed field survey concentrated on evaluation of ponds current state and the functioning of the drain and the spillway protective dick. Based on field survey, the revitalization was divided into three steps that dealed with retention capacity improvement, facilities renovation, dam renovation and ecosystem stability improvement. The revitalization program would be supported by Ministry of the Environment of the Czech Republic due to high financial demands.