955 resultados para sewage constituents
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Some Ecological Factors Affecting the Input and Population Levels of Total and Faecal Coliforms and Salmonella in Twelve Mile Creek, Lake Ontario and Sewage Waters Near St. Catharines, Ontario. Supervisor: Dr. M. Helder. The present study was undertaken to investigate the role of some ecological factors on sewage-Dorne bacteria in waters near St. Catharines, Ontario. Total and faecal coliform levels and the presence of Salmonella were monitored for a period of a year along with determination of temperature, pH, dissolved oxygen, total dissolved solids, nitrate N, total phosphate P and ammonium N. Bacteriological tests for coliform analysis were done according to APHA Standard Methods by the membrane filtration technique. The grab sampling technique was employed for all sampling. Four sample sites were chosen in the Port Dalhousie beach area to determine what bacteriological or physical relationship the sites had to each other. The sample sites chosen were the sewage inflow to and the effluent from the St. Catharines (Port Dalhousie) Pollution Control Plant, Twelve Mile Creek below the sewage outfall and Lake Ontario at the Lakeside Park beach. The sewage outfall was located in Twelve Mile Creek, approximately 80 meters from the creek junction with the beach and piers on Lake Ontario. Twelve Mile Creek normally carried a large volume of water from the WeIland Canal which was diverted through the DeCew Generating Station located on the Niagara Escarpment. An additional sample site, which was thought to be free of industrial wastes, was chosen at Twenty Mile Creek, also in the Niagara Region of Ontarioo 3 There were marked variations in bacterial numbers at each site and between each site, but trends to lower_numbers were noted from the sewage inflow to Lake Ontario. Better correlations were noted between total and faecal coliform population levels and total phosphate P and ammonium N in Twenty Mile Creek. Other correlations were observed for other sample stations, however, these results also appeared to be random in nature. Salmonella isolations occurred more frequently during the winter and spring months when water temperatures were minimal at all sample stations except the sewage inflow. The frequency of Salmonella isolations appeared to be related to increased levels of total and faecal coli forms in the sewage effluent. However, no clear relationships were established in the other sample stations. Due to the presence of Salmonella and high levels of total and faecal coliform indicator organisms, the sanitary quality of Lake Ontario and Twelve Mile Creek at the sample sites seemed to be impaired over the major portion of the study period.
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3-alkyl-2-methoxypyrazines (MPs) are grape- and insect-derived odor-active compounds responsible for vegetative percepts that are detrimental to wine quality when elevated. This study tested both the effect of closure/packaging types and light/temperature storage conditions on MPs (isopropyl-, secbutyl-, and isobutyl-MP) in wine. An MP-emiched wine rapidly (after 140 hours) and significantly decreased in MP concentration after natural and synthetic cork contact (immersion of closures in wine). This decrease was greatest with synthetic closures (70% - 89% reduction) and secbutyl-MP. Subsequently storage trials tested the effects of commercial closure/packaging options (natural cork, agglomerate cork, synthetic corks, screwcaps and TetraPak® cartons) on MPs in MP-emiched Riesling and Cabernet Franc over 18 months. Regardless of packaging, isobutyl-MP was the most altered from bottling. Notably, all MP levels tended to decrease to the greatest extent in TetraPak® cartons (~34% for all MPs) and there was evidence of contribution ofisoproyl- and secbutyl-MP from cork-based closures (i.e. ~30% increase in secbutyl-MP after 6 months) or from an unidentified wine constituent. To test the effects of various light/temperature conditions (light exposed at ambient temperature in three different bottle hues, light excluded at ambient temperature and light excluded at a "cellar" temperature (14°C)), MP-emiched Riesling and Cabernet Franc were also analyzed for MP concentrations over 12 months. MPs did not vary consistently with light or temperature. Other odorants and physico-chemical properties were tested in all wines during storage trials and closely agree with previous literature. These results provide novel insights into MPs during ageing, interactions with packaging and storage conditions, and assist in the selection of storage conditions/packaging for optimal wine quality.
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The initial timing of face-specific effects in event-related potentials (ERPs) is a point of contention in face processing research. Although effects during the time of the N170 are robust in the literature, inconsistent effects during the time of the P100 challenge the interpretation of the N170 as being the initial face-specific ERP effect. The interpretation of the early P100 effects are often attributed to low-level differences between face stimuli and a host of other image categories. Research using sophisticated controls for low-level stimulus characteristics (Rousselet, Husk, Bennett, & Sekuler, 2008) report robust face effects starting at around 130 ms following stimulus onset. The present study examines the independent components (ICs) of the P100 and N170 complex in the context of a minimally controlled low-level stimulus set and a clear P100 effect for faces versus houses at the scalp. Results indicate that four ICs account for the ERPs to faces and houses in the first 200ms following stimulus onset. The IC that accounts for the majority of the scalp N170 (icNla) begins dissociating stimulus conditions at approximately 130 ms, closely replicating the scalp results of Rousselet et al. (2008). The scalp effects at the time of the P100 are accounted for by two constituent ICs (icP1a and icP1b). The IC that projects the greatest voltage at the scalp during the P100 (icP1a) shows a face-minus-house effect over the period of the P100 that is less robust than the N 170 effect of icN 1 a when measured as the average of single subject differential activation robustness. The second constituent process of the P100 (icP1b), although projecting a smaller voltage to the scalp than icP1a, shows a more robust effect for the face-minus-house contrast starting prior to 100 ms following stimulus onset. Further, the effect expressed by icP1 b takes the form of a larger negative projection to medial occipital sites for houses over faces partially canceling the larger projection of icP1a, thereby enhancing the face positivity at this time. These findings have three main implications for ERP research on face processing: First, the ICs that constitute the face-minus-house P100 effect are independent from the ICs that constitute the N170 effect. This suggests that the P100 effect and the N170 effect are anatomically independent. Second, the timing of the N170 effect can be recovered from scalp ERPs that have spatio-temporally overlapping effects possibly associated with low-level stimulus characteristics. This unmixing of the EEG signals may reduce the need for highly constrained stimulus sets, a characteristic that is not always desirable for a topic that is highly coupled to ecological validity. Third, by unmixing the constituent processes of the EEG signals new analysis strategies are made available. In particular the exploration of the relationship between cortical processes over the period of the P100 and N170 ERP complex (and beyond) may provide previously unaccessible answers to questions such as: Is the face effect a special relationship between low-level and high-level processes along the visual stream?
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Cet article a précédemment été publié par le Dalhousie Law Journal.
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The problem investigated is on the haematological aspects of two freshwater pulmonate snails, Indoplanorbis exustus (Deshayes),and Lymnaea acuminata f.rufescens (Gray). An important aspect of the present investigation is to emphasize the utilization of freshwater organisms as models for research directed at understanding the basic biomedical problems that remain unresolved. Another aspect is to demonstrate how haemolymph can be treated as a tissue because of late, it has been shown that several parameters of blood can be taken as reliable indicators for diagnostic purposes, and also to monitor environmental pollution. The various haematological parameters studied are total haemocyte number,packed cell volume, haemoglobin, and inorganic as well organic constituents in three size groups of both the snail species. The effect of copper toxicity was measured in terms of total haemocyte count, and the activity pattern of selected phosphatases and transaminases.The study concluded that enzyme activity levels can be taken as reliable indicators to monitor pollution. Age is a factor that determines several of the physiological, biochemical and metabolic activities. This study also indicates that haemolymph can be taken as an organ system to study the various changes taking place at organ systems levels.
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The present study is an attempt to understand the physiological responses of a freshwater gastropod, in terms of haematological parameters, in normal conditions as well as in various natural and man made altered conditions of the environment.Pila virens, a freshwater prosobranch,commonly found in paddy fields, ponds, and streams of Kerala is selected as the test animal for the present investigation. Various haemolymph constituents such as total carbohydrate, glycogen, total protein, total lipid, urea,ammonia,sodium,potasium, calcium, and chloride which are directly involved in the control and maintenance of different physiological systems, were analysed in the present study. Selected haematological parameters like total haemocyte number, and packed cell volume were also determined. Besides , the activity pattern of selected haemolymph enzymes such as acid phosphatase (ACP), alkaline phosphatase (ALP),Glutamate-oxaloacetate transaminase (GOT), and glutamate-pyruvate transaminase (GPT), all having diagnostic value in terms of internal defence system and metabolism of the organism, were also studied.
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In this thesis all these aspects are taken into consideration. Extensive studies were conducted on all aspects of processing of crabs, mussels and clams. The species taken for studies are commercially used ones namely Scylla sereta, perna viridis, and villorita cyprinoids. In Chapter 4.1 with regard to crab) the following aspects on their handling and processing are reported seasonal variation of chemical constituents, changes taking place during ice storage, freezing, canning etc. In Chapter 4._2 with regard to mussel, the relation between age (size) and chemical constituents, changes taking place during ice storage, freezing, canning etc. are reported and in Chapter 4.3 the changes taking place in clam muscle during icing and freezing are reported and the ame rebility of ice stored clams for canning purpose is reported.The interference of high concentration of glycogen in mussel and clam muscles during the colour development of ribose (Me-jbaum's method) is observed and remedial step are taken to minimise the interference.
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Nitrification is the biological oxidation of ammonium, first to nitrite and then to nitrate by two groups of aerobic, chemolithotrophic bacteria belonging to the family Nitrobacteriaceae. The biological nitrification in municipal wastewater treatment is important in those cases were ammonia removal requirement specially exist. In a trickling filter or in an activated sludge system nitrification is rate limiting and thus necessitates longer detention time. The combined carbon oxidation-nitrification processes generally have low population of nitrifiers due to a high ratio of BOD to total nitrogen in the effluent. This necessitates, separate carbon and nitrogen oxidation processes, which thus minimizes wash out ofthe nitrifiers. Therefore, a separate stage nitrification has become essential to achieve faster and efficient removal of ammonia from the wastewater. The present work deals with the development of bio reactor for nitrifying of sewage as the tertiary process so that the treated wastewater can be used for irrigation, algal culture or fish culture
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The subsequent chapters of the Thesis deal with the toxic effects of mercury, copper, zinc und~1ead on these bivalve molluecs, their accumulation and distribution among various organs of the animals and also the motel retention winstica by the three species. Static biousauy tests have been conducted in these studies. It was found that the concentrations of the various metals studied in these organism are well below the permitted level given far ease ahellfienes (crab and ehrimgi and that these maliuscs are very good integrators ef trace metals from their environment and may be used as an indicator organism sf metal pallutaute. The present investigutionsemphaeie the need for a clean coastal water and gives a serious warning regarding the possiblc route of heavy metals in ta human body thraugh marine food chain.
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The nearshore marine ecosystem is a dynamic environment impacted by many activities, especially the coastal waters and sediments contiguous to major urban areas. Although heavy metals are natural constituents of the marine environment, inputs are considered to be conservative pollutants and are potentially toxic, accumulate in the sediment, are bioconcentrated by organisms and may cause health problems to humans via the food chain. A variety of metals in trace amounts are essential for biological processes in all organisms, but excessive levels can be detrimental by acting as enzyme inhibitors. Discharge of industrial wastewater, agriculture runoff and untreated sewage pose a particularly serious threat to the coastal environment of Kerala, but there is a dearth of studies in documenting the contaminant metals. This study aimed principally to assess such contamination by examining the results of heavy metal (Cu, Pb, Cr, Ni, Zn, Cd and Hg) analysis in seawater, sediment and benthic biota from a survey of five transects along the central and northern coast of Kerala in 2008 covering a 10.0 km stretch of near shore environment in each transect. Trophic transfer of metal contaminants from aquatic invertebrates to its predators was also assessed, by employing a suitable benthic food chain model in order to understand which all metals are undergoing biotransference (transfer of metals from a food source to consumer).The study of present contamination levels will be useful for potential environmental remediation and ecosystem restoration at contaminated sites and provides a scientific basis for standards and protective measures for the coastal waters and sediments. The usefulness of biomonitor proposed in this study would allow identification of different bioavailable metals as well as provide an assessment of the magnitude of metal contamination in the coastal marine milieu. The increments in concentration of certain metals between the predator and prey discerned through benthic food chain can be interpreted as evidence of biotransference.
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The optimum growth requirements of two nitrifying consortia developed from treated sewage by enrichment technique were determined by a series of experiments. There was total inhibition of nitrification at above 2.75 g r' NH/- Nand 2.5g r' N02' - N and the ammonia oxidizing consortium preferred a pH at 8.5 and the nitrite oxidizing consortium a pH of 7.5 as the optima for nitrification. Optimum temperatures were between 20° and 30°C for both the groups. As the rate of airnow was increased from I to 7 Ilmin, the build-up of N02- -N increased 10-fold and the consumption of N02- -N increased by a factor of 28.8 implying that the ammonia oxidizing consortium in a bioreactor required three times more aeration than that for nitrite oxidizers for ex pressing their full nitrifying potential. These data directly contribute for developing a fermentati on process for the mass production of nitrifiers as well as for designing bio reactors for nitrifying sewage.
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Plants and microorganisms provide the pharmaceutical industry with some of the most important sources of components for the research of new medications This thesis involves the study of three medicinal plants belonging to three different important families viz, Cyperus rotundus (Cyperaceae), Stereospermum colais (Bignoniaceae) as well as the well known medicinal plant Zingiber officinale (Zingiberaceae) as the third. The first chapter gives an overview of biologically active natural products with special reference to antioxidant, antidiabetic, anti-inflammatory and antimicrobial molecules from terrestrial sources. Chapter 2 of the thesis deals with the isolation of phytochemical constituents of the medicinal plant Cyperus rotundus and its antioxidant and radical scavenging potential. Chapter 3 of the thesis describes the studies on the roots of Stereospermum colais, A Bignoniaceae plant belonging to the genus Stereospermum which is used extensively. Chapter 3 of the thesis describes the studies on the roots of Stereospermum colais, a Bignoniaceae plant belonging to the genus Stereospermum which is used extensively in Ayurveda. Chapter 4 describes the biological potential of rhizomes of Zingiber officinale. Ethyl acetate extract of ginger (EAG) possessed antioxidant activity as is evident from the results of various in vitro assays compared to other extracts .In conclusion, medicinal plants Cyperus rotundus and Stereospermum colais have been analysed for their phytochemical constituents. Also, the positive results obtained from biological activity studies such as antioxidant, anti-inflammatory and antimicrobial activity on the isolated compounds/extracts add on to the medicinal properties of these plants. Apart from that, ethyl acetate extract of Zingiber officinale (ginger) rhizomes has been shown to have very good biological potential including glucose lowering and adipocyte differentiation inhibitory effect.