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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Assessing the effects of water and sediment quality on aquatic macro-invertebrate diversity in the Steelpoort River, Olifants River System, Limpopo Province

Matlou, Katlego Shirley January 2017 (has links)
Thesis (M.Sc. (Zoology)) -- University of Limpopo, 2017 / In this study data was collected to establish if the water and sediment quality of the Steelpoort River has any effects on macro-invertebrate species. The Steelpoort River is a tributary of the Olifants River system but not much data about the water quality is available. The Steelpoort River is a perennial river (Ashton et al. 2001) situated west of Burgersfort and from there it flows in a north- easterly direction and converges with the Olifants River in the Drakensberg near Kromellenboog. High silt levels in the river, increases the risk of flooding and leads to the smothering of in-stream habitats resulting in loss of some invertebrate and fish species. Sampling of the water, sediment and macroinvertebrates was conducted quarterly at the Steelpoort River at five sites. One site was above the impoundment (De Hoop Dam) and the rest were below the impoundment. A handheld YSI 556™ Multi Probe System (MPS instrument and a Mettler Toledo SevenGo™ conductivity meter were used to measure the physico-chemical characteristics at the sites. The macroinvertebrates were sampled using the SASS 5 bio-assessment protocol (Goodyear & McNeill 1999, Dickens & Graham 2002). Macro-invertebrate samples were collected using a 400 mm x 400 mm SASS net with a 250 μm mesh size. The substrate was disturbed for a period of two minutes to free macro-invertebrates from the substrate. The SASS score for each site was evaluated in the field for three of the five samples. The macro-invertebrate samples were preserved in 70% ethanol and sorted to family level in the University of Limpopo’s Biodiversity laboratory. For the majority of the physico-chemical parameters the most elevated were detected downstream and lowest concentrations were detected upstream. Analysis of variance (ANOVA) indicated that there were no significant differences for electrical conductivity, salinity, and TDS, between the sites (p>0.05). There were however significant differences in the temperature, dissolved oxygen, turbidity, and pH concentrations (p<0.05). The majority of the metals and metalloids in the water (Fe, Mn, V, Co, Zn, Ba, and Cu) were highest at Tiershoek (Site1) and lowest at Steelpoort (Site 4) and Burgersfort Bridge (Site 5).The mean metal concentrations collected showed elevated levels for chromium, copper and zinc, which were above the CCME sediment guidelines. The most abundant macroinvertebrates were from the family Ephemeroptera which are pollution sensitive and good indicators of pollution in aquatic ecosystems. When using the interpretation of the SASS 5 results from Chutter 1995, the mean Average Score Per Taxa (ASPT) scores show that the water quality for Tiershoek (Site 1) and Polopark (Site 3) is natural but the habitat diversity has been reduced. For De Hoop (Site 2) and Steelpoort (Site 4), the mean ASPT score shows that there is some deterioration in the water quality. Finally, for Burgersfort Bridge (Site 5), the mean ASPT score indicates that there is major deterioration in the water quality. Primer statistical analysis indicated that the average dissimilarity between sites showed that the highest dissimilarity was between Tiershoek (Site 1) and Burgersfort Bridge (Site 5) which was conclusive with the results from the macro-invertebrate count and SASS, indicating that there is diverse difference from upstream to downstream. CCA indicated positive correlations between nutrients detected at Steelpoort with Athericidae, Tabanidae, Gomphidae, Baetidae, Elmidae, Planaria, Psephenidae, and Libellulidae which was indicated that water chemistry characteristics exert influence on macroinvertebrates. The results showed that there is degradation of the water quality in river from upstream to downstream with more pollution tolerant species being abundant at Steelpoort (Site 4) and Burgersfort Bridge (Site 5). The most favourable season was autumn and the least summer/spring and this may be attributed to the life cycle of the macro-invertebrate communities / NRF VLIR
82

Estimation of suspended sediment yield flowing into Inanda Dam using genetic programming

Jaiyeola, Adesoji Tunbosun January 2016 (has links)
Submitted in fulfilment of the requirements of the degree of Master of Engineering , Durban University of Technology, Durban, South Africa, 2016. / Reservoirs are designed to specific volume called the dead storage to be able to withstand the quantity of particles in the rivers flowing into it during its design period called its economic life. Therefore, accurate calculation of the quantities of sediment being transported is of great significance in environment engineering, hydroelectric equipment longevity, river aesthetics, pollution and channel navigability. In this study different input combination of monthly upstream suspended sediment concentration and upstream flow dataset for Inanda Dam for 15 years was used to develop a model for each month of the year. The predictive abilities of each of the developed model to predict the quantity of suspended sediment flowing into Inanda Dam were also compared with those of the corresponding developed Sediment Rating Curves using two evaluation criteria - Determination of Coefficient (R2) and Root-Mean-Square Error (RMSE). The results from this study show that a genetic programming approach can be used to accurately predict the relationship between the streamflow and the suspended sediment load flowing into Inanda Dam. The twelve developed monthly genetic programming (GP) models produced a significantly low difference when the observed suspended sediment load was compared with the predicted suspended sediment load. The average R2 values and RMS error for the twelve developed models were 0.9996 and 0.3566 respectively during the validation phase. The Genetic Programming models were also able to replicate extreme hydrological events like predicting low and high suspended sediment load flowing into the dam. Moreover, the study also produced accurate sediment rating curve models with low RMSE values of between 0.3971 and 11.8852 and high R2 values of between 0.9833 and 0.9962. This shows that sediment rating curves can be used to predict historical missing data of the quantity of suspended sediment flowing into Inanda Dam using existing streamflow datasets. The results from this study further show that the predictions from the Genetic Programming models are better than the predictions from the Sediment Raring Curve models, especially in predicting large quantities of suspended sediment load during high streamflow such as during flood events. This proves that Genetic Programming technique is a better predictive tool than Sediment Raring Curve technique. In conclusion, the results from this study are very promising and support the use of Genetic Programming in predicting the nonlinear and complex relationship between suspended sediment load and streamflow at the inlet of Inanda Dam in KwaZulu-Natal. This will help planners and managers of the dam to understand the system better in terms of its problems and to find alternative ways to address them.
83

A review of the management of the dredging silt/sand from Hong Kong waters

Lau, Shing-cheong., 劉勝昌. January 2003 (has links)
published_or_final_version / Environmental Management / Master / Master of Science in Environmental Management
84

Abundance of nonprescription pharmaceuticals in central Indiana streams and effects on sediment microbial activity

Bunch, Aubrey R. January 2009 (has links)
Access to abstract permanently restricted to Ball State community only / Indirect effects of human population growth on stream ecosystem function : sediment respiration and nutrient uptake response to nonprescription pharmaceuticals -- Frequency and distribution of nonprescription pharmaceuticals in central Indiana streams. / Access to thesis permanently restricted to Ball State community only / Department of Biology
85

The impact of water and sediment quality on the health of Oreochromis Mossambicus (Peters, 1852) and Schilbe Intermedius Ruppell, 1832 at the Phalaborwa Barrage in the Olifants River

Gohell, Ashla Fiona January 2014 (has links)
Thesis (MSc. (Zoology)) -- University of Limpopo, 2014 / The Olifants River is presently one of the most threatened river systems in South Africa. The Upper and Middle catchments are heavily impacted by anthropogenic activities, however little is known of the status of the river in the Lower catchment in the Limpopo Province. Thus the aim of this study was to evaluate the impact of water quality on the health of Oreochromis mossambicus and Schilbe intermedius at the Phalaborwa Barrage. This was achieved through assessing the water (seasonally) and sediment quality (bi-annually) at three sites in the Phalaborwa Barrage (inflow, middle and the wall). Ten specimens of each of the two selected fish species were seasonally collected using gill nets of different mesh sizes from May 2010 to January 2011. The water, sediment and the dorsal muscle tissues from both fish species were analysed for selected metals at an accredited laboratory by means of ICP-OES spectrometry and the human health risk factor upon consumption of fish contaminated with metals was assessed. Fish health was determined at the field laboratory by applying the HAI, PI and IPI. In addition, the condition factor (CF) was determined for the selected fish species during all seasons. All water constituents with the exception of turbidity during spring (wall), anions (Cl, F and SO4) and cations (Ca, K, Mg and Na) fell within the target water quality range (TWQR) for aquatic ecosystems throughout the study. Inorganic nitrogen concentrations showed eutrophic (spring) and oligotrophic conditions (autumn, winter and summer), while phosphorus indicated eutrophic (autumn, winter and spring) and hypertrophic (summer) conditions throughout the study. There was no significant difference in anions (F=0.07; df=3; p=0.97), cations (F=0.57; df=3; p=0.64) and nutrients (F=0.79; df=3; p=0.56) detected in water. The metals that were detectable in the water samples were: Al, Fe, Sn, B, Sr, Se, Ba, Mn, Sb and As, while in sediment all metals (Fe, Al, Ti, Mn, Ba, B, Zn, Ag, V, Cr, Ni, Sr, Sn, Co, Cu, Cd, Pb, As and Sb) were detected with the exception of Se. The average metal concentrations detected above the TWQR are; Al, Fe, Se, Sn, Sb and As, in the sediment only Cr and Cd were above suggested quality guidelines. There was no significant difference in metals detected in water (F=0.05; i df=3; p=0.98) and sediment (F=1.62; df=1; p=0.21). Higher HAI values were recorded for S. intermedius than O. mossambicus, indicating that O. mossambicus was in better health than S. intermedius. For S. intermedius, parasites contributed the most to the total HAI followed by abnormal liver conditions, haematocrit levels (internal variables) and abnormal gills (external variable). While for O. mossambicus, parasites, liver, haematocrit (internal variables), gills, eyes, fins and skin (external variables) contributed to the HAI values. There was no significant difference in HAI values for O. mossambicus (F=1.9; df=3; p=0.15) and S. intermedius (F=2.58; df=3; p=0.66) throughout the study. The PI and IPI for ectoparasites for both fish species, were higher than the PI for endoparasites. There was a significant difference for PI values of O. mossambicus (F=0.07; df=3; p=0.041) and S. intermedius (F=3.65; df=3; p=0.019) during the study. Oreochromis mossambicus had higher CF values than S. intermedius and both fish species had values that indicated good fish. Metals that were detectable in O. mossambicus muscle tissue included: Ba, B, Zn, Fe, Sr, Al, Mn, Cr, Ag, Pb, Ni, Cu, Se, V, Sb, Ti, Sn and Co, while for S. intermedius Ba, B, Zn, Fe, Al, Cr, Sr, Mn, Cu, As, Pb, Se, Sn, Ag, Ti, Ni, Sb and Co were recorded. There was no significant difference in bioaccumulation levels between the two fish species (F=1.412; df=3; p=0.250). The human health risk assessment indicated that fish muscle tissues are unsuitable for continuous (weekly/daily) consumption. As some carcinogenic metals i.e. Pb, Cr and Sb for O. mossambicus and Pb, As and Cr for S. intermedius were detected at HQ levels of more than 50 times the recommended value of one. In conclusion, the Phalaborwa Barrage is impacted by metals (Al, Fe, Se, Sn, Sb and As) and occasionally with nutrients. The water and sediment quality and metal bioaccumulation have confirmed the latter statement and to a lesser extent the HAI, PI and IPI. The human risk assessment done indicated that continuous consumption of fish by humans, especially O. mossambicus may have adverse effects on the health of humans.
86

Longitudinal trends in grain size, shear stress and sediment mobility along sedimentary links of a Canadian Shield river, Saguenay Region : a geomorphic perspective on assessing Atlantic salmon (Salmo salar) productivity in rivers

Davey, Chad E. January 2004 (has links)
The segmenting of gravel-bed rivers into 'sedimentary links', characterized by single-sediment sources and downstream fining of alluvial sediments, is a relatively new technique which has had limited application. The sedimentary link concept has been primarily applied to alpine river environments where link formations are supplied by coarse sediment from active point sources. The purpose of this study is to apply the sedimentary link concept on the Ste Marguerite River in the Saguenay region of the Canadian Shield, where valley-segment deposits of coarse sediment from ancient glacial processes are dominant in forming links. / Specifically, this study examines link-scale trends in surface grain size and channel slope. This study also uses the sedimentary link concept within an ecological context to explain the spatial organization and quality of Atlantic salmon spawning and rearing habitat. (Abstract shortened by UMI.)
87

Temporal variation of pharmaceuticals in Indiana streams and degradation potential by sediment microbial communities

Veach, Allison M. 09 July 2011 (has links)
This study examined temporal variation of pharmaceutical concentrations in two streams with differing land uses: 1) a suburban stream with combined sewer overflow point sources; and, 2) a rural stream influenced by septic systems and agricultural runoff. Sites were sampled monthly for pharmaceutical concentrations and stream physiochemical parameters. Pharmaceuticals were frequently detected in both the urban and agricultural stream with the highest concentrations measured during winter. Across sites, water column dissolved oxygen concentrations positively correlated with several pharmaceuticals suggesting microbial activity is important in pharmaceutical persistence. Potential for degradation of pharmaceuticals as a carbon or nitrogen source by stream sediment microbial communities was also estimated using pharmaceutical-amended basal salt media incubated under different temperature and ultraviolet (UV) light treatments. Under 4°C incubation, caffeine and acetaminophen were the most recalcitrant compounds whereas cotinine was the most labile. Under UV-B exposure, cotinine and sulfamethoxazole were the most recalcitrant compounds whereas ibuprofen was the most labile. / Temporal variation of pharmaceuticals in an urban and agriculturally influenced stream -- Degradation potential of six pharmaceuticals by sediment microbial communities. / Department of Biology
88

What the Orne River tells about the former steelmaking activities : chemical and mineralogical investigations on sediments / Sur les traces de l'ancienne activité sidérurgique en Lorraine : chimie et minéralogie des sédiments de l'Orne

Kanbar, Hussein 11 July 2017 (has links)
En Lorraine, l’Orne, un affluent de la Moselle, a été affecté par une activité minière et industrielle qui s’est intensifiée depuis le milieu du XIXe siècle et au cours du XXe siècle. Les barrages, créés pour les besoins en eau de l’industrie, ont favorisé l’accumulation de dépôts sédimentaires contaminés en métaux. En effaçant les barrages qui ont perdu leur fonctionnalité première, le cours d’eau devrait retrouver un fonctionnement hydrologique plus naturel, requis par la directive cadre européenne sur l’eau (DCE 2000/60/CE). Les travaux de recherche présentés ont mis en évidence les différents dépôts sédimentaires dans la partie d’aval de l’Orne. Des sédiments ont été prélevés en surface et carottés afin d’être précisément caractérisés d’un point de vue minéralogique et géochimique. Ces analyses ont permis de mettre en évidence le caractère fortement contaminé des dépôts sédimentaires en présents en amont des barrages. De plus, il a été possible, de distinguer les contributions industrielles et naturelles. Ces contributions industrielles mettant en évidence une forte contribution de boues sidérurgiques. L’étude de la minéralogie du fer et de la spéciation du zinc a mis en évidence des marqueurs minéralogiques qui devraient permettre de tracer les sédiments contaminés au sein de la colonne d’eau lors de leur remise en suspension. L’étude de la spéciation chimique du Zn a montré que cet élément était essentiellement stocké sous forme de sulfures. La prédominance de la taille nanométrique à sub-micrométrique de ces sulfures renforce leur probabilité de remobilisation lors d’opérations de réaménagement du cours d’eau ou lors d’évènements hydrologiques intenses (crues) / The Orne River is a tributary of the Moselle River, located northeastern France. During the last two centuries, the Orne watershed was highly industrialized. The introduction of wastes or by-products into the river is highly anticipated. Based on industrial needs, some small dams were built. However, the Directive 2000/60/EC of the European parliament strongly incite the removal of engineered structures (such as dams). This raises the question about the fate of contaminated sediment remobilization. The aims of this work are to identify the different sediment deposits along the Orne River. Surface sediments and sediment cores were collected along the Orne River. The sediments were then analyzed for water content, grain size distribution, pH, major and trace chemical composition using ICP-OES and ICP-MS, respectively, major crystalline minerals (XRD), micrometric (light microscope and SEM) and sub-micrometric (TEM) mineralogy, and Zn speciation at a molecular level (XANES). The chemical and mineralogical composition of the surface sediments revealed lithogenic as well as anthropogenic contributions. Interestingly, the sediment layers of the core collected upstream of the Beth dam showed fingerprints of the former steelmaking facilities. Those deposits were highly enriched in Fe, Zn and Pb, and were fingerprinted by crystalline iron minerals, and by newly formed Fe-aluminosilicates. TEM-EDXS and XANES at the Zn K-edge observations evidenced that Zn was mainly carried as sulfides, and to a lesser extent associated to Fe oxy-hydroxides and Fe-aluminosilicates. The remobilization of the contaminated sediments can then be traced by the unique mineralogical composition
89

Uso de invertebrados aquáticos na avaliação da toxicidade da água e do sedimento contaminados por efluentes de esgoto doméstico

Tulio, Juliana 12 March 2014 (has links)
No Brasil a lei ambiental vigente estabelece que os efluentes não possam causar efeitos agudo ou crônico para a biota dos corpos hídricos. No presente estudo foram avaliados os efeitos toxicológicos de amostras de água superficial e sedimento integral, de três locais três locais próximos a uma estação de tratamento de esgotos domésticos, coletadas em um rio na região de Curitiba, Estado do Paraná. As amostras foram submetidas a testes de toxicidade aguda e crônica, com os invertebrados aquáticos D. magna e C. sancticaroli. Além dos testes ecotoxicológicos, foram mensurados DBO, DQO, Fósforo Total, Nitrogênio Amoniacal Total, e Coliformes termotolerantes, com as amostras de água superficial. A composição do sedimento integral foi avaliada com a Espectrometria de Fluorescência de Raios-X por Energia Dispersiva (EDXRF), para a determinação dos elementos químicos presentes nestas amostras. Os resultados das análises de DBO, DQO, Fósforo total, Nitrogênio amoniacal total, e Coliformes termotolerantes, demonstraram que possivelmente ocorreu a contaminação da água superficial por esgoto doméstico, para as amostras analisadas nas 3 campanhas. A composição dos sedimentos é compatível com os tipos de solos presentes nos respectivos locais, porém houve variação quantitativa de elementos como o silício, alumínio e ferro no decorrer das campanhas, parecendo não influenciar diretamente nos testes. Os resultados dos testes para toxicidade aguda com matriz água e sedimento não expressaram toxicidade para D. magna e C. sancticaroli. Para os testes de toxicidade crônica com água superficial, o efeito observado foi o acréscimo da reprodução em D. magna. Aspectos como letalidade e a ausência do desenvolvimento da maturidade sexual foram verificados em amostras puras, provenientes do ponto próximo da ETE em todas as campanhas, após 10 dias de teste para D. magna. As amostras de sedimento integral não promoveram letalidade nos Daphnideos, entretanto ocorreu o acréscimo da reprodução. Para C. sancticaroli, exposto ao sedimento integral, ocorreu o desenvolvimento anormal do comprimento dos organismos, emergindo em adultos até o 8o dia de teste crônico. / In Brazil the environmental law in force establishes that wastewaters can not cause acute or chronic effect to the water bodies’ biota. In the present study were evaluated the ecotoxicological effects of surface water and whole sediment samples, from three sites located nearby a wastewater treatment plant, that were collected from a river in the region of Curitiba, state of Paraná. The samples were submitted to acute and chronic toxicity tests, utilizing the aquatic invertebrates D. magna and C. sancticaroli. Besides the ecotoxicological tests, BOD, COD, Total Phosphorus, Total Nitrogen Ammonia and Thermotolerant coliforms were measured from the surface water samples. The whole sediment composition was evaluated by Energy-dispersive X- Ray Fluorescence Spectrometry (EDXRF) to determine chemical elements present in these samples. The BOD, COD, Total Phosphorus, Total Nitrogen ammonia, and Thermotolerant coliforms analysis’ results possibly demonstrated surface water contamination by domestic sewage, for the samples analyzed in 3 campaigns. The sediment composition is compatible with the kinds of soils present in the respective sites, however there were quantitative variation of chemical elements during the campaigns, such as silicon, aluminum and iron, not seeming to directly influence the tests. The test results for acute toxicity with water and sediment matrix have not expressed toxicity to D. magna and C. sancticaroli. For chronic toxicity tests with surface water, the observed effect was the reproduction increase in D. magna. Aspects such as lethality and the absence of sexual maturity development were observed in pure samples accruing from the nearest point of the WTP in all campaigns, after 10 test days for D. magna. The whole sediment samples have not promoted lethality in Daphnideos, although a reproduction increase occurred. For C. sancticaroli, exposed to the whole sediment, an abnormal length development of the organisms occurred, emerging in adults until the 8th chronic test day.
90

Uso de invertebrados aquáticos na avaliação da toxicidade da água e do sedimento contaminados por efluentes de esgoto doméstico

Tulio, Juliana 12 March 2014 (has links)
No Brasil a lei ambiental vigente estabelece que os efluentes não possam causar efeitos agudo ou crônico para a biota dos corpos hídricos. No presente estudo foram avaliados os efeitos toxicológicos de amostras de água superficial e sedimento integral, de três locais três locais próximos a uma estação de tratamento de esgotos domésticos, coletadas em um rio na região de Curitiba, Estado do Paraná. As amostras foram submetidas a testes de toxicidade aguda e crônica, com os invertebrados aquáticos D. magna e C. sancticaroli. Além dos testes ecotoxicológicos, foram mensurados DBO, DQO, Fósforo Total, Nitrogênio Amoniacal Total, e Coliformes termotolerantes, com as amostras de água superficial. A composição do sedimento integral foi avaliada com a Espectrometria de Fluorescência de Raios-X por Energia Dispersiva (EDXRF), para a determinação dos elementos químicos presentes nestas amostras. Os resultados das análises de DBO, DQO, Fósforo total, Nitrogênio amoniacal total, e Coliformes termotolerantes, demonstraram que possivelmente ocorreu a contaminação da água superficial por esgoto doméstico, para as amostras analisadas nas 3 campanhas. A composição dos sedimentos é compatível com os tipos de solos presentes nos respectivos locais, porém houve variação quantitativa de elementos como o silício, alumínio e ferro no decorrer das campanhas, parecendo não influenciar diretamente nos testes. Os resultados dos testes para toxicidade aguda com matriz água e sedimento não expressaram toxicidade para D. magna e C. sancticaroli. Para os testes de toxicidade crônica com água superficial, o efeito observado foi o acréscimo da reprodução em D. magna. Aspectos como letalidade e a ausência do desenvolvimento da maturidade sexual foram verificados em amostras puras, provenientes do ponto próximo da ETE em todas as campanhas, após 10 dias de teste para D. magna. As amostras de sedimento integral não promoveram letalidade nos Daphnideos, entretanto ocorreu o acréscimo da reprodução. Para C. sancticaroli, exposto ao sedimento integral, ocorreu o desenvolvimento anormal do comprimento dos organismos, emergindo em adultos até o 8o dia de teste crônico. / In Brazil the environmental law in force establishes that wastewaters can not cause acute or chronic effect to the water bodies’ biota. In the present study were evaluated the ecotoxicological effects of surface water and whole sediment samples, from three sites located nearby a wastewater treatment plant, that were collected from a river in the region of Curitiba, state of Paraná. The samples were submitted to acute and chronic toxicity tests, utilizing the aquatic invertebrates D. magna and C. sancticaroli. Besides the ecotoxicological tests, BOD, COD, Total Phosphorus, Total Nitrogen Ammonia and Thermotolerant coliforms were measured from the surface water samples. The whole sediment composition was evaluated by Energy-dispersive X- Ray Fluorescence Spectrometry (EDXRF) to determine chemical elements present in these samples. The BOD, COD, Total Phosphorus, Total Nitrogen ammonia, and Thermotolerant coliforms analysis’ results possibly demonstrated surface water contamination by domestic sewage, for the samples analyzed in 3 campaigns. The sediment composition is compatible with the kinds of soils present in the respective sites, however there were quantitative variation of chemical elements during the campaigns, such as silicon, aluminum and iron, not seeming to directly influence the tests. The test results for acute toxicity with water and sediment matrix have not expressed toxicity to D. magna and C. sancticaroli. For chronic toxicity tests with surface water, the observed effect was the reproduction increase in D. magna. Aspects such as lethality and the absence of sexual maturity development were observed in pure samples accruing from the nearest point of the WTP in all campaigns, after 10 test days for D. magna. The whole sediment samples have not promoted lethality in Daphnideos, although a reproduction increase occurred. For C. sancticaroli, exposed to the whole sediment, an abnormal length development of the organisms occurred, emerging in adults until the 8th chronic test day.

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