Cu is one of the most toxic elements that affect fish populations when the fish are exposed to concentrations exceeding their tolerance. To investigate the effects of elementary Cu on aspects of bioconcentration, histology and behaviour, O. mossambicus were exposed to 0 and 0.75 ± 0.20 mg/l of Cu for 96 hours (short-term study), and 0, 0.11 ± 0.02, 0.29 ± 0.02, and 0.47 ± 0.04 mg/l of Cu for 64 days (longterm study) under controlled conditions in the laboratory. For the long-term study fish were sampled for gills, liver, and kidney Cu accumulation analysis after 1, 32 and 64 days of exposure and after 1, 2, 4, 16, 32, and 64 days for gills, liver and spleen histology analysis. Cu accumulation was concentration-duration dependent with the highest accumulation capacity in the liver. A multifactor linear model was developed for the relationship between exposure dose, exposure duration and Cu accumulation in the organs with the liver model: Log L = 3.35 + 0.85W + 0.31T (r² = 0.892) giving a better fit than the gills: G = −35.09 + 10.58W + 17.58T (r² = 0.632). Where L = Cu accumulation values in the liver, G = Cu accumulation values in the gills (both in μg/g dry mass); W = exposure dose in water (mg/l); and T = exposure time (days). Using this model Cu accumulation in organs can be estimated when exposure concentration and duration is known. This model should be tested under different conditions to determine the potential of the model in monitoring Cu toxicity in the environment. Lesions were observed in the liver, gills and spleen in all Cu treatments at all exposure concentration and exposure durations. However, the incidence and the degree of alteration was related to the concentration of Cu and duration of exposure. The sequential appearance of lesions in the order of, hepatic vacuolar degeneration, fatty degeneration and necrosis indicated a gradual increase in liver damage with larger duration of exposure time and increasing Cu concentration. The initial lesions in the gills were manifested as hypertrophy and hyperplasia of the gill epithelium causing increase in the thickness of the secondary lamellae, mucous cell hypertrophy and proliferation, mucous hypersecretion, proliferation of eosinophilic granule cells and hyperplasia of interlamellar cells. With increase in exposure time, necrosis of the eosinophilic granule cells, lamellar oedema, epithelial desquamation and increase in severity of lamellar hyperplasia were observed. These lesions indicated an initial defence mechanism of the fish against Cu toxicity followed by advanced histological changes that were related to Cu concentration and duration of exposure. Changes in the spleen were haemosiderosis, increase in the white pulp and macrophage centres, reduction in the red pulp, and necrosis suggesting that fish exposed to environmentally relevant levels of Cu may be histopathologically altered leading to anaemia and immunosuppression. Regression analysis was used to quantify the relationship between the total activity of the fish, and duration of exposure. There was a gradual decline in fish activity related to Cu concentration and duration of exposure before introducing food into the tanks. There was a constant activity after introducing food in the tanks at the control and 0.11 ± 0.02 mg/l Cu exposure levels irrespective of exposure time. Analysis of covariance (ANCOVA) was used to test for the difference in slopes between treatments. There was no significant difference (p > 0.05) between slopes of the control and 0.11 ± 0.02 mg/l Cu, and between 0.29 ± 0.02 and 47 ± 0.04 mg/l Cu before and after introducing food in the tanks. The slopes of both the control and 0.11 ± 0.02 mg/l Cu were significantly different from those of 0.29 ± 0.02 and 0.47 ± 0.04 mg/l Cu (p < 0.05). There were significant differences in the mean opercular movements per minute between treatments (p < 0.05). There was hyperventilation at 0.11 ± 0.02 mg/l Cu i.e. 87 ± 18 opercular movements per minute (mean ± standard deviation) and hypoventilation at 0.29 ± 0.02 and 0.47 ± 0.04 mg/l Cu i.e. 37 ± 34 and 13 ± 6 opercular movements per minute compared to the control. Hypo- and hyperventilation were related to the lesser and greater gill damage, respectively. In conclusion Cu accumulation and effects on histology of the liver, gills and were related to the concentration of Cu in the water and duration of exposure showing a gradual increase in incidence and intensity with larger duration of exposure time and increasing Cu concentration. The fish were initially able to homeostatically regulate and detoxify Cu. However, as the exposure continued, the homeostatic mechanism appears to have failed to cope with the increasing metal burden causing advanced histological changes.

Water quality studies conducted in the recent past in the Lower Fraser River Basin indicated that locally some high pollution levels exist. With further urbanization and industrialization of the Vancouver region an increase in waste loadings and a degradation of water quality can be expected if no strict pollution control is applied. Of particular concern are biologically undegradable substances such as heavy metals and poly-chlorinated hydrocarbons. They accumulate in the sediments of the river and the estuary and become concentrated in organisms of the food chain. Pollution is a gradually occurring process. Anticipation of potential problems is important for the decision maker responsible for water quality management. The Fraser River supports one of the largest salmon runs of the world and is abundant with other commercially and recreationally valuable fish. Salmon are very sensitive to pollution and could disappear from the Fraser river system as they already have from many other major rivers if pollution levels become too high. The Fraser River estuary has the function of a bottleneck. Adult salmon enter the river to migrate upstream to their spawning grounds, and juvenile salmon stay in the estuary for a while to acclimatize themselves to the saline environment. In this thesis a method is presented to simulate the effects of potential pollution on the size of a salmon stock. A model which uses data from various life stages of a particular sockeye salmon run in the Fraser system is developed. Uncertainties due to environmental fluctuations are accounted for. Using this model the effects of an increase in mortality rate in two stages of the sockeye salmon life cycle on adult return numbers are studied. The analysis showed that at a certain mortality rate chances are that the stock might not be able to recover. In light of a planned salmon enhancement program to increase salmon stocks in various Pacific rivers, the fact that decreasing water quality could counteract all enhancement efforts should be a warning signal to the decision makers. The development of a water quality index to predict future conditions is recommended and a possible procedure to relate water quality parameters to an increase in mortality rate is sketched out. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Lethal toxicity values (96 h LC50; mg Cd/L) for the test species were similar: Lepomis cyanellus, 11.52; Notropis lutrensis, 6.62; Pimephales promelus, 3.58. However the effects of cadmium concentration and exposure time on temperature tolerance varied between species. Neither cadmium concentration nor exposure time had a significant effect on the CTM of green sunfish. Both cadmium concentration and exposure time had a significant effect on the CTMs of red shiners and fathead minnows. By day 10 mean CTMs were 2.3 t- 4.5 C (red shiners) and 4.2 to 5.7 C (fathead minnows) lower than control CTM. These results suggest a potential problem in cadmium contaminated systems for high environmental temperatures to stress or kill fish.

The objective of this study was to evaluate the impact of extreme acidic and alkaline pH excursions of fish populations in streams receiving fly ash settling basin effluent. Fish communities were sampled above and below the effluent outfall in a mountain stream, Adair Run, adjacent to the coal-fired Glen Lyn Power Plant in southwestern Virginia. This effluent, which exhibited a pH increase of up to pH 9.3 as the basin nearly filled, contributed to a downstream decline in species diversity and an increased dominance of the stoneroller (Campostoma anomalum), which displaced more sensitive species. Laboratory avoidance studies, utilizing a steep-gradient trough apparatus, were used to investigate the potential role of avoidance behavior that may alter fish distributions in acidic and alkaline waters. Stonerollers, rainbow trout (Salmo gairdneri), golden shiners (Notemigonus crysoleucas) and spotfin shiners (Notropis spilopterus) exhibited first significant avoidance responses to continuously decreasing pH conditions at pH 6.0-7.0, well above the 96-hr LC50 values of 4.05 and 4.24 for trout and golden shiners, respectively. When the pH was gradually increased, avoidance thresholds of pH 9.5- 11.0 were observed, beyond the 96-hr LC50 values of 9.13 and 8.86 for trout and golden shiners. Single acute alkaline exposures initially yielded more rapid avoidance responses, with acclimation to alkaline conditions frequently occurring within 30 minutes. Gill histological alterations, as observed by transmission electron microscopy, were detected following exposure to extreme pH excursions, with more rapid changes occurring with alkaline exposures. Gill tissue showed marked recovery within 8-14 days. / Master of Science

Changes in heart rate, ventilatory activity and oxygen consumption were determined in trout (Salmo gairdneri) and brown bullhead catfish (Ictalurus nebulosus) during exposure to a steadily increasing concentration of waterborne cyanide selected to produce death in 8-9 hours for each species. The lethal cyanide concentration for the bullheads was an order of magnitude higher than for trout. Trout developed an immediate and gradually increasing bradycardia throughout the exposure period. Cyanide produced tachycardia in the bullhead followed by a gradual onset of bradycardia as the concentration of cyanide was raised. Pericardial injection of atropine (a muscarinic cholinergic antagonist) indicated that bradycardia in the trout was due initially to increased vagal tone but later due to the direct effect of cyanide on the heart. Hyperventilation in the trout persisted throughout the exposure period, although the rate and amplitude fluctuated and was variable between individual fish. During the last hour of exposure (highest cyanide concentration), ventilation was characterized by rapid, shallow breaths with a sudden respiratory arrest. The bullheads showed hyperventilation during the first 3 hours of exposure followed by a gradual, linear drop in ventilation rate and amplitude until death occurred. Cardiac and ventilatory responses in both species were attributed to stimulation of central and peripheral chemoreceptors by cyanide. Evidence is presented which suggests the initial response in the bullheads was due, at least in part, to gustatory stimulation by the cyanide. Oxygen consumption of the trout remained above pre-exposure levels for the majority of the test period. Oxygen consumption in the bullhead paralleled the changes in heart and ventilatory rates. Whole-body lactate and pyruvate levels of fingerlings of both species during cyanide exposure were measured to estimate the extent of anaerobiosis. Whole-body lactate levels were greater in the bullheads than the trout, indicating a higher capacity for anaerobiosis, probably due to a greater fuel supply. Whole-body pyruvate levels in both species did not change from control levels until the last hour of cyanide exposure. / M.S.

Bluegill were exposed to 3 and 30 pg/L lindane and 20 and 200 pg/L naphthalene to determine uptake rate constants, K1 depuration rate constants, K2, and bioconcentration factors, BCF. Correlations were determined between lipid normalized and non-lipid normalized BCFs, and between observed Kl, K2 and BCFs and predicted values. The K1 values for both chemicals and concentrations were similar. The K2 values were different (1.04 day~1, 0.46 day 1). Naphthalene was more rapid. BCFs for lindane (315) and naphthalene (98) were different. Lipid normalized BCFs for naphthalene were more variable than non-lipid normalized BCFs. The reverse was observed for lindane BCFs. Predicted K1, K2 , and BCFs were in agreement with observed values.

published_or_final_version / Ecology and Biodiversity / Master / Master of Philosophy

Made available in DSpace on 2015-06-17T19:34:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-01-21. Added 1 bitstream(s) on 2015-06-18T12:48:47Z : No. of bitstreams: 1 000829802.pdf: 1465255 bytes, checksum: 2d7e1dd40db91bb9503377e7965f6c9d (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação do Instituto de Biociências (FUNDIBIO) / Inserido na realidade de contaminação dos rios amazônicos pelo mercúrio, este trabalho busca, por meio do estudo metaloproteômico, a identificação e a caracterização de proteínas do tecido muscular de três espécies diferentes de peixes do rio Madeira que possam atuar como possíveis biomarcadores da toxicidade deste elemento na região de influência do Aproveitamento Hidrelétrico de Jirau (AHE JIRAU). As estratégias para este estudo foram separadas em três componentes distintos: de seletividade, de sensibilidade e estrutural. Ao longo desta pesquisa, diferentes metodologias foram empregadas nessas etapas para o estudo metaloproteômico: componente de seletividade - 2D PAGE no fracionamento bidimensional das proteínas; componentes de sensibilidade - SR XRF e GFAAS para identificação e quantificação do mercúrio nos spots proteicos, respectivamente; componente estrutural - ESI MS MS na caracterização das proteínas identificadas com mercúrio em sua estrutura. As espécies de peixes estudadas foram: dourada (Brachyplatystoma rousseauxii), pacu (Mylossoma sp., Myleus sp.) e jaraqui (Semaprochilodus sp.). Entre os resultados obtidos, a 2D PAGE se mostrou eficiente no fracionamento proteico do tecido muscular de peixes. Utilizando análises qualitativas por SR XRF foi possível identificar a presença de mercúrio no spot 68 da dourada (massa molar 20,8 kDa e pI 5,6) e no spot 72 do pacu (massa molar 19,8 kDa e pI 7,5). Determinações por GFAAS permitiram a quantificação do mercúrio no tecido muscular e em 28 spots, que apresentaram concentrações de 11,3 a 41,2 mg g-1 de mercúrio em sua composição; esses resultados possibilitaram o cálculo da estimativa do número de átomos de mercúrio por molécula de proteína entre os spots estudados. Após análise por ESI MS MS, foi possível caracterizar oito proteínas com diferentes isoformas em 21 spots que apresentaram pI de 3,5 a 9,8 e massa molar ... / Inserted in the context of mercury contamination of Amazonian rivers, this work pursues through metaloproteomic study the identification and characterization of proteins from muscle tissue of three different species of fish from Madeira River that may act as potential biomarkers of toxicity of this element in the region of influence of Jirau Power Plant. The strategies for this study were separated into three distinct components: selectivity, sensitivity and structural. Throughout this research, different methodologies were used in these steps for metaloproteomic study: component of selectivity - 2D PAGE in two-dimensional proteins fractionation; components of sensitivity - SR XRF and GFAAS for mercury identification and quantification in protein spots, respectively; structural component - ESI MS MS in the characterization of proteins identified with mercury in its structure. The species studied were: dourada (Brachyplatystoma rousseauxii), pacu (Mylossoma sp., Myleus sp.) and jaraqui (Semaprochilodus sp.). Among the results, the 2D PAGE proved efficient in protein fractionation of fish muscle tissue. Using qualitative analysis by SR XRF was possible to identify the presence of mercury in the spot 68 of dourada (molar mass of 20.8 kDa and pI 5.6) and spot 72 of pacu (molar mass of 19.8 kDa and pI 7.5). Determinations by GFAAS allowed the mercury quantification in muscle tissue and in 28 spots that showed concentrations from 11.3 to 41.2 mg g-1 of mercury in its composition; these results enabled an estimative calculation of the number of mercury atoms per protein molecule between the spots studied. After analysis by ESI MS MS it was possible to characterize eight proteins with different isoforms in 21 spots that showed pI 3.5 to 9.8 and molar mass between 9.9 and 18.1 kDa, indicating that these proteins may be potential candidates for mercury biomarkers in ...

Orientador: Pedro de Magalhães Padilha / Banca: Clelia Akiko Hiruma Lima / Banca: Marília Afonso Rabelo Buzalaf / Banca: Paulo dos Santos Roldan / Banca: Lincolin Carlos Silva de Oliveira / Resumo: Inserido na realidade de contaminação dos rios amazônicos pelo mercúrio, este trabalho busca, por meio do estudo metaloproteômico, a identificação e a caracterização de proteínas do tecido muscular de três espécies diferentes de peixes do rio Madeira que possam atuar como possíveis biomarcadores da toxicidade deste elemento na região de influência do Aproveitamento Hidrelétrico de Jirau (AHE JIRAU). As estratégias para este estudo foram separadas em três componentes distintos: de seletividade, de sensibilidade e estrutural. Ao longo desta pesquisa, diferentes metodologias foram empregadas nessas etapas para o estudo metaloproteômico: componente de seletividade - 2D PAGE no fracionamento bidimensional das proteínas; componentes de sensibilidade - SR XRF e GFAAS para identificação e quantificação do mercúrio nos spots proteicos, respectivamente; componente estrutural - ESI MS MS na caracterização das proteínas identificadas com mercúrio em sua estrutura. As espécies de peixes estudadas foram: dourada (Brachyplatystoma rousseauxii), pacu (Mylossoma sp., Myleus sp.) e jaraqui (Semaprochilodus sp.). Entre os resultados obtidos, a 2D PAGE se mostrou eficiente no fracionamento proteico do tecido muscular de peixes. Utilizando análises qualitativas por SR XRF foi possível identificar a presença de mercúrio no spot 68 da dourada (massa molar 20,8 kDa e pI 5,6) e no spot 72 do pacu (massa molar 19,8 kDa e pI 7,5). Determinações por GFAAS permitiram a quantificação do mercúrio no tecido muscular e em 28 spots, que apresentaram concentrações de 11,3 a 41,2 mg g-1 de mercúrio em sua composição; esses resultados possibilitaram o cálculo da estimativa do número de átomos de mercúrio por molécula de proteína entre os spots estudados. Após análise por ESI MS MS, foi possível caracterizar oito proteínas com diferentes isoformas em 21 spots que apresentaram pI de 3,5 a 9,8 e massa molar ... / Abstract: Inserted in the context of mercury contamination of Amazonian rivers, this work pursues through metaloproteomic study the identification and characterization of proteins from muscle tissue of three different species of fish from Madeira River that may act as potential biomarkers of toxicity of this element in the region of influence of "Jirau Power Plant". The strategies for this study were separated into three distinct components: selectivity, sensitivity and structural. Throughout this research, different methodologies were used in these steps for metaloproteomic study: component of selectivity - 2D PAGE in two-dimensional proteins fractionation; components of sensitivity - SR XRF and GFAAS for mercury identification and quantification in protein spots, respectively; structural component - ESI MS MS in the characterization of proteins identified with mercury in its structure. The species studied were: "dourada" (Brachyplatystoma rousseauxii), "pacu" (Mylossoma sp., Myleus sp.) and "jaraqui" (Semaprochilodus sp.). Among the results, the 2D PAGE proved efficient in protein fractionation of fish muscle tissue. Using qualitative analysis by SR XRF was possible to identify the presence of mercury in the spot 68 of "dourada" (molar mass of 20.8 kDa and pI 5.6) and spot 72 of "pacu" (molar mass of 19.8 kDa and pI 7.5). Determinations by GFAAS allowed the mercury quantification in muscle tissue and in 28 spots that showed concentrations from 11.3 to 41.2 mg g-1 of mercury in its composition; these results enabled an estimative calculation of the number of mercury atoms per protein molecule between the spots studied. After analysis by ESI MS MS it was possible to characterize eight proteins with different isoforms in 21 spots that showed pI 3.5 to 9.8 and molar mass between 9.9 and 18.1 kDa, indicating that these proteins may be potential candidates for mercury biomarkers in ... / Doutor

D.Phil. / By virtue of its position on the eastern border of South Africa, the Kruger National Park (KNP) receives the flow of six main riven, of which the greater part of the specific catchment areas are situated upstream from the park itself. The Olifants River has the largest catchment area both in size and in proportion of catchment area beyond the park boundary. Increased competing demand for water by the urban, industrial, mining and agricultural sectors within the catchment boundaries of the Olifants River has focused attention on the ecological water requirements of the river. Of particular concern was the high degree of mineralisation of the Olifants River due to mining activities on the western boundary of the KNP. When one considers the demand for water by the Kruger National Park it is evident that water is required for more than one use, i.e. for potable use, game watering and ecosystem (aquatic and riparian) maintenance. In order to facilitate proper water quality management it is necessary to develop a comprehensive water quality management plan for the river. The development of such a plan requires a thorough understanding of the fate and effects of pollutants in the environment. It is furthermore important to have reliable information on the trends and status of important water quality determinants in these systems. This study was therefore aimed at investigating the metal ecotoxicology of the lower Olifants River and the Selati River, a tributary of the Olifants River which flows through the Phalaborwa area. Water quality is a driving variable in aquatic ecosystems. Full assessment of water quality of the Olifants River included evaluation of the physical, chemical and biological attributes of the system. The difference between the physical/chemical and biological attributes is that the former provide an instantaneous and often specific assessment of the water quality, whereas the latter integrate changes in the system over time. Water and sediment samples were collected bi-monthly from February 1990 to February 1992 at six stations along the lower Olifants River, one in the Selati River and one in the Letaba River. At each of these sites physical and chemical water quality characteristics were measured. Two metal bioaccumulation indicator species, Labeo rosae and Oreochromis mossambicus, were also sampled during the same period at three stations in the Olifants River and at the Selati River sampling station. Two additional surveys were undertaken to reference sites in the KNP (i.e. Pioneer Dam, and Nhlanganini Dam) during February 1992 and April 1992 respectively. Tissue samples (muscle, gill, liver, gonads, fat and blood) were collected and analysed for Cr, Cu, Fe, Mn, Ni, Pb and Zn using atomic absorption spectrophotometry. The routine monitoring of chemical and physical water quality attributes produces large quantities of complex data which are often difficult to interpret. To reduce the complexity, data may be standardised and summarised into an index. The Aquatic Toxicity Index (ATI) that was developed Metal Ecotoxicology in the Olifants River it Summary during this study presented the water quality of all the sampling stations, during each survey as a single value. This value reflected the water quality's suitability-for-use by fish at the different sampling stations. The ATI showed definite temporal and spatial trends in water quality in the Olifants River. The Selati River was the main contributing factor to the poor water quality measured in the Olifants River within the KNP. This was due to high TDS, metal and fluoride concentrations. Deterioration of the water quality was experienced during flood conditions when the turbidities and total metal concentrations increased. The water quality generally increased between summer and winter surveys (February to June). Bioindicators are species used to quantify biologically available level of metals in the aquatic ecosystem. These organisms take up metals from the ambient water and from food, and the concentrations in their tissues (or changes in concentrations) provide a time integrated measure of metal bioavailability. Temporal bioavailability of metals in the tissues of the bioindicators showed similar trends to the water quality. Highest metal concentrations were measured in fish tissue samples collected during flood conditions (December 1990) and during low-flow conditions (June to October). This was attributed to increased exposure due to metal adsorption to suspended sediments during the flood conditions and to increased ambient metal concentrations during lowflow conditions. The distribution of metals in tissues varied based on the uptake, depuration and metabolism strategies for each metal. In general the gill tissue bioaccumulated the highest metal concentrations, with only Cu and Fe occurring in higher concentrations in liver tissue. Significant positive correlation's were found between bioaccumulation in muscle tissue and the other tissues: Space-bulking and time-bulking of results were carried out to elucidate spatial bioaccumulation patterns. The highest bioaccumulation of Cu, Pb and Ni were recorded in samples from the Selati River, whereas Zn and Cr concentrations were the highest in the Olifants River. An equilibrium partitioning (EP) technique was used to integrate bioaccumulation data and metal concentrations in different phases of the water and sediment and produce specific Cu and Zn criteria for the Olifants and Selati rivers. Although there is a multitude of data available for Cu and Zn toxicity and BCF's, the quality criteria produced during this study, for the first time, made use of results obtained under local conditions. The results from bioaccumulation studies carried out in the field can not provide information regarding the potential effects or the risks the metals may pose to the exposed organisms. Therefore the susceptibility of the organisms to metal contamination can be determined using laboratory studies. Physiology is toxicology's closest relative and contributes markedly in assessing the toxicological risk of metals. Bioassays were conducted to determine the uptake kinetics, acid-base disturbances and haematological effects of a metal mixture containing Cu, Fe and Zn on Tilapia sparrmanii. The effects of the individual metals (Cu, Fe and Zn) and different Metal Ecotoxicology