Dissertations / Theses on the topic 'Aquatic toxicology'
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1
Sved, Daniel W. "Monooxygenase induction and lethality as endpoints in aquatic toxicology." W&M ScholarWorks, 1991. https://scholarworks.wm.edu/etd/1539616869.
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Spot, Leiostomus xanthurus, were exposed to suspended sediments (&\approx&20 mg/L) contaminated with polycyclic aromatic hydrocarbons (PAH) in a laboratory flow-through system to evaluate the applicability of hepatic ethoxyresorufin O-deethylase (EROD) induction as an indicator of PAH exposure. PAH sources tested were coal-tar creosote (CTC), a low molecular weight fraction of creosote (LMWF), and a high molecular weight fraction of creosote (HMWF). A standard 96-h acute toxicity test was conducted to ensure that PAH concentrations tested in induction studies were sub-acutely toxic. The 96-h LC50 for spot was 1740 &\mu&g PAH/L (95% confidence interval = 1480-2060 &\mu&g PAH/L). The lowest concentration producing an observable effect in 96 h was 560 &\mu&g PAH/L; no effects were observed for spot exposed to 250 &\mu&g PAH/L for 96 h. Induction of hepatic EROD activity occurred rapidly in fish exposed to high environmentally realistic concentrations of CTC or the HMWF, but not the LMWF. Maximal induction (30-fold) occurred in fish exposed for 48 h to 150 &\mu&g PAH/L. Induction was concentration-dependent up to 150 &\mu&g PAH/L; at 320 &\mu&g PAH/L induction was 14-fold. EROD activity decreased upon further exposure; by day 7, EROD activity was not significantly different than that on day 0. EROD activity in fish exposed to 16 &\mu&g PAH/L was not consistently higher than that in control fish. Spot exposed to at least 70 &\mu&g PAH/L from CTC or the HMWF experienced severe fin erosion, epidermal lesions, and mortality beginning a few days after maximal EROD induction occurred. No relationship between EROD induction and whole animal responses is implied, only that EROD induction did precede any high order effects. These results indicate complications to the use of EROD activity as a sensitive, reliable indicator of PAH exposure. The toxicity of CTC may inhibit or interfere with continued induction of EROD activity, but neither the toxicity nor inducing capability is associated with the LMWF. The lack of exposure-dependent EROD induction indicate there could be difficulties in interpreting field studies, where fish have unknown exposure histories.
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Méndez, Sara I. Semlitsch Raymond D. "Aquatic and terrestrial exposure of amphibians to estrogenic endocrine disrupting contaminants." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6183.
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Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 15, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dissertation advisor: Raymond D. Semlitsch Vita. Includes bibliographical references.
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Smith, E. C., Phillip R. Scheuerman, and Kurt J. Maier. "Toxicity of Nanomaterials to Aquatic Organisms." Digital Commons @ East Tennessee State University, 2005. https://dc.etsu.edu/etsu-works/2939.
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Webb, Diane. "Assessment of the health of the Swan-Canning river system using biochemical markers of exposure of fish." Thesis, Curtin University, 2005. http://hdl.handle.net/20.500.11937/62.
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Most environmental studies concerning the environmental health of the Swan- Canning River system have focussed on nutrient inputs from both rural and urban catchments that are the cause of algal blooms. On occasions these algal blooms have resulted in fish deaths attributed to oxygen starvation. Relatively few studies have examined whether non-nutrient contamination is affecting the health of the riverine environment. Those studies that have, have concentrated on measuring the levels of heavy metals, organochlorines, organophosphates, and hydrocarbons in the sediments and water of the river system, and in the flesh of the biota. However, chemical analysis often fails to detect chemicals of concern due to high laboratory detection limits. In addition, analysis of the body burden of contaminants within biota does not necessarily convey if exposure is inducing adverse effects at the individual or ecosystem levels. The use of biochemical markers as a tool for the assessment of the health of the Swan-Canning River system was examined under a collaborative research project with the Waters and Rivers Commission, established in response to the recognition of the paucity of information from chemical analyses. The present study focussed on the estuarine portion of the Swan-Canning River system, using the black bream (Acanthopagrus butcheri), an estuarine dependent fish species, as a biomonitoring tool. Prior to the commencement of this study it had been determined that the black bream was a suitable fish species for use as a biomonitoring tool when using mixed function oxygenase (MFO) activity induction under laboratory conditions.Biopsies taken from feral black bream collected from eight sites during the period 2000 to 2002 from the estuary confirmed that the use of MFO induction in this fish species as a biomarker of exposure to organic contaminants is a reliable biomarker. Fish gender was a confounding factor in the interpretation of MFO induction when using the enzyme ethoxyresorufin-O-deethylase (EROD) as EROD activity was suppressed in both pre- and post-spawning female black bream. No such suppression was identified when using the MFO enzyme ethoxycoumarin-O-deethylase (ECOD). However, due to differences in the pattern and intensity of the induction of EROD and ECOD activities it was concluded that ECOD activity was not a substitute for EROD activity to detect certain chemical as ECOD activity represents a different cytochrome P450 pattern to EROD activity. No spatial, seasonal or interannual differences in the level of the enzyme sorbitol dehydrogenase (SDH) in the blood of the black bream were measured indicating that the interpretation of MFO activity induction was not compromised by hepatocellular damage. This study has shown that the black bream in the Swan-Canning Estuary are exposed to, and are metabolising polycyclic aromatic hydrocarbons (PAHs), notwithstanding that the chemical analysis of the contaminant load of these substances in the estuarine waters is consistently below laboratory detection limits. In addition, biomarker responses such as ECOD activity indicate that various other organic pollutants are present and are being metabolised by the black bream.The measurement of biliary metabolites clearly show that, under winter conditions, the comprehensive drainage system of the Swan Coastal Plain contributes PAHs from pyrogenic sources such as burnt fuels into the estuary although the onset and intensity of rainfall events notably impacts on the volume of stormwater inflow. During the summer months, when freshwater flow is minimal, petrogenic sources of PAHs are dominant. Metabolic enzyme analysis points to the black bream being challenged in their aerobic capacities during summer, and that gill tissue was the most suitable tissue to evaluate the aerobic and anaerobic capacity of this fish species. Furthermore, there was a significant negative correlation between stress protein (hsp70) expression and DNA integrity in field-collected fish suggesting that the black bream within the estuary are highly stressed. No gradient of response in biomarker levels was identified in the Swan-Canning Estuary under either winter or summer conditions indicating there are multiple sources of inputs of potential pollutants along the length of the estuary. Stormwater and road runoff are the primary source of pollutant input into the estuary in the winter months, while summer biomarker levels, particularly PAH, appear to reflect the high usage of the estuary for recreational purposes and runoff from poorly irrigated parks and gardens. Significant rainfall events at any time of the year have the potential to adversely impact the biota of the estuary, particularly when these events result in a flush of water from the drains following long dry periods.The study shows that the black bream is a suitable fish species to use under field conditions to detect the presence of bioavailable non-nutrient contamination within the Swan-Canning Estuary. A suite of biomarkers in black bream have been tested seasonally and annually but only a small number of biomarkers have proven suitable for routine monitoring of the health of the Swan-Canning Estuary. This treatise concludes with several recommendations for further investigations into biomarkers of fish health for the purpose of increasing our understanding on the sources and type of contamination entering the estuary, and potential effects on the aquatic biota of the Swan-Canning River system. These recommendations include, but are not limited to: (1) the need to determine baseline levels for the different biomarkers investigated in this study, (2) the examination of the Moore River or the Warren River estuaries as potential reference sites for biomarker studies in the Swan- Canning Estuary, (3) the advantage of identifying a second estuarine-dependent indigenous fish as a biomonitoring tool, (4) the requirement for a targeted study aimed at clarifying the relationship between major drain discharges, biomarker levels and impacts on river biota, and (5) a study of estuarine waters utilising SPMDs be undertaken in tandem with biomarker analysis of field captured fish would be beneficial.
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Gausman, Maria M. "A COMPARISON OF DUCKWEED AND STANDARD ALGAL PHYTOTOXICITY TESTS AS INDICATORS OF AQUATIC TOXICOLOGY." Miami University / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=miami1153752259.
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Wong, Wing-yu, and 黃詠如. "Ecotoxicological effects of selected engineered nano-materials to aquatic organisms in relation to their physicochemicalcharacteristics." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2011. http://hub.hku.hk/bib/B47869410.
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Engineered nanomaterials (NMs), defined as artificially made particles possessing at least one dimension within 1 – 100 nm range, have different physical and biological properties from bulk materials of the same chemistry due to their increased surface areas. Their novel properties have facilitated the prolific growth of commercial NM-incorporating products. NMs may be leached into the aquatic environment during the product life-cycle, but their ecological impacts on marine ecosystems are currently largely unknown. Therefore, this study primarily aimed to investigate the physicochemical characteristics (particle and aggregate sizes, dissolution rate) and in vivo toxicities of commonly-used metallic NMs to marine organisms under various environmental scenarios.
First, in vivo ecotoxicity screening tests, using the marine diatom Skeletonema costatum and the rotifer Brachionus sp., were conducted for nine common nano metal oxides which had been applied in various commercial products. Among them, nano zinc oxide (nZnO) and nano magnesia (nMgO) were found to be the most toxic NMs to both organisms, as they induced oxidative stress by increasing reactive oxygen species (ROS) production in the organism. The endocrine disrupting potential of nZnO was revealed by its modulation of transcriptions of the genes for retinoid X receptor (RXR) in the rotifer. Conversely, nano alumina (nAl2O3) and nano indium oxide (nIn2O3) were the least toxic NMs.
Due to its high potency, toxicity of nZnO was further evaluated using five marine organisms (i.e., microalgae Thalassiosira pseudonana and S. costatum, copepod Tigriopus japonicus, amphipod Elasmopus rapax, and medaka Oryzias melastigma). Crustaceans were generally more sensitive to nZnO. Toxicity of nZnO was mainly attributed to metal ion dissolution, although nanoparticulate effects such as aggregation and adhesion of nZnO onto the animal’s exoskeleton as well as physical disruption of cell structures could not be discounted.
Due to the fact that the dissolution of nZnO decreased from 16 mg Zn L-1 at 4°C to 1.4 mg Zn L-1 at 35°C, and Zn ion was the main contributing factor for nZnO toxicity at 25°C, it was postulated that nZnO toxicity would increase with decreasing temperature. This hypothesis was tested with S. costatum, O. melastigma and the amphipod Melita longidactyla through a factorial design experiment (i.e., 2 concentrations x 4 temperatures). In agreement with the hypothesis, the growth of S. costatum was significantly inhibited by nZnO at the lowest test temperature (15°C). However, contradictive results were observed in the two animal species. For instance, the amphipod could reduce the nZnO uptake and its toxicity by undergoing metabolic depression and dormancy at lower temperatures.
As the morphology and coating of NMs utilized in commercial products may differ from those employed in toxicity studies, T. japonicus was exposed to nZnO-containing sunscreens to assess the effects of nZnO and Zn2+ released in seawater during epidermal applications. Based on their genetic biomarker responses, the results suggested that other components in sunscreens could react synergistically or antagonistically on nZnO toxicity. Clearly, there is a need for further study of the combined effects of NMs and other common chemical contaminants to marine organisms.published_or_final_version
Biological Sciences
Doctoral
Doctor of Philosophy
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Cho, Eun-ah. "Bioturbation as a novel method to characterize the toxicity of aquatic sediment." NCSU, 2005. http://www.lib.ncsu.edu/theses/available/etd-02282005-111535/.
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Bioturbation, the biological process through which many species of infaunal benthic invertebrates suspend bottom sediments into the water column through their burrowing, feeding, respiratory, and locomotor activities, may be a sub-lethal endpoint that can be exploited to assess the toxicity of aquatic sediments. Therefore, we developed a novel test method that used bioturbation (BioTurbTox test) generated by the activities of second in-star Chironomus tentans larvae as the toxicity endpoint (Chapter 2). To validate this method, copper (Cu) and fluoranthene were individually spiked into relatively uncontaminated aquatic sediment to assess changes in bioturbation and mobilization of the chemicals into the overlying water. Turbidity production responded to the chemicals in the sediment in a concentration-dependent manner and was an excellent indicator of sediment toxicity. Moreover, substantial concentrations of Cu were released into the overlying water from the Cu-spiked sediment, whereas little fluoranthene was mobilized into the overlying water from the fluoranthene-spiked sediment. Sediment samples were then collected from the field and used to evaluate the similarity of response of the BioTurbTox test to other more standardized toxicity tests. In the summer of 2003, sediment samples were collected at six sites in the Neuse River of North Carolina tested for toxicity, and analyzed for chemical contaminants (Chapter 3). Atrazine was the most frequently detected current-use pesticide and pyrene and fluoranthene were measured at relatively high concentrations from the Neuse River sites. Concentrations of fluoranthene were correlated with results from the Ceriodaphnia dubia porewater and BioTurbTox tests. We concluded that the new BioTurbTox test was useful as a rapid screening method for sediment toxicity information, but required normalization to the clay content or to the total organic carbon content of field collected sediments. In Chapter 4, the toxicity of environmental pharmaceuticals and personal care products (PPCPs) were evaluated with the BioTurbTox and C. dubia reproductive tests. Fluoxetine and bisphenol A significantly affected bioturbation caused by C. tentans, especially at high concentrations (1-2 mg/L), and the turbidity change induced by caffeine, fluoxetine, and bisphenol A showed a concentration-response relation. Triclosan affected reproduction of C. dubia at relatively low concentrations (IC50: 85.4 ?Ýg/L). However, most of the tested PPCPs were not acutely toxic at environmentally relevant concentrations, but were relatively toxic at high concentrations. In Chapter 5, two sediment-spiking methods (extract mixing vs. whole sediment dilution methods) were compared with the BioTurbTox test and a gradient response was observed from both methods. Based on the similarity of the toxic response, we determined that either of the spiking methods was appropriate for estimating the toxicity of aquatic sediments in screening level assessments. The overall conclusion from this research was that the newly developed BioTurbTox test shows promise as a tool to assess the toxicity and mobilization of contaminants from aquatic sediments.
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Atkinson, Susanna Kate. "The persistence of steroidal estrogens in the aquatic environment." Thesis, University of Ottawa (Canada), 2009. http://hdl.handle.net/10393/28120.
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The presence and fate of the steroidal estrogens, estrone (E1), 17beta-estradiol (E2) and 17alpha-ethinylestradiol (EE2), in Ottawa and Cornwall wastewater treatment plants (WWTP's), drinking water, and the river water used as the drinking water source, were identified. Estrogens were extracted using accelerated solvent extraction, gel permeation chromatography and solid phase extraction, and identified using gas chromatography-mass spectrometry and internal C-13 standards. E1, E2 and EE2 concentrations ranged from 1.8 to 370, 24.3 to 66.9 and 0.4 to 9.8 ng L-1, respectively, and were affected by weather variables such as temperature and precipitation, and WWTP parameters such as daily flow and carbonaceous biochemical oxygen demand. Photodegradation rate constants under ultraviolet B radiation for E1 were directly proportional to radiation intensity and sample thickness, and inversely proportional to dissolved organic carbon concentration, but EE2 was remarkably persistent. A luciferase reporter gene assay found estrogenicity in both sewage effluent and UVB-exposed samples of estrogens, contributed by the degradation products of steroidal estrogens. Finally, EE2 persistence was also seen in a time-course experiment in which goldfish were exposed to 25 ng L-1 EE2. A mass-balance model calculated a bioconcentration factor (BCF) for EE2 in fish blood of 1400, whereas measured data revealed a maximum BCF of only 500.
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Cronin, Mark T. D. "Quantitative structure-activity relationships of comparative toxicity to aquatic organisms." Thesis, Liverpool John Moores University, 1990. http://researchonline.ljmu.ac.uk/4989/.
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Quantitative Structure-Activity relationship (QSAR) attempt statistically to relate the physico-chemical properties of a molecule to its biological activity. A QSAR analysis was performed on the toxicities of up to 75 organic chemicals to two aquatic species, Photobacterium phospherum (known as the Microtox test), and the fathead minnow. To model the toxicities 49 physico-chemical and structural parameters were produced including measures of hydrophobicity, molecular size and electronic effects from techniques such as computational chemistry and the use of molecular connectivity indices. These were reduced to a statistically more manageable number by cluster analysis, principal component analysis, factor analysis, and canonical correlation analysis. The de-correlated data were then used to form relationships with the toxicities. All the techniques were validated using a testing set. Some good predictions of toxicity came from regression analysis of the original de-correlated variables. Although successful in simplifying the complex data matrix, principal component analysis, factor analysis, and canonical content analysis were disappointing as predictors of toxicity. The performance of each of the statistical techniques is discussed. The inter-species relationships of toxicity between four Commonly utilised aquatic endpoints, fathead minnow 96 hour IC50, Microtox 5 minute EC50, Daphnia magna 48 hour IC50, and Tetrahymena pyriformis 60 hour IG50, were investigated. Good relationships was found between the fathead minnow and both T. pyriformis and D. magna toxicities indicating that these species could be used to model fish toxicity. The outliers from individual relationships were assessed in order to elucidate if any molecular features may be causing greater relative toxicity in one species as compared to another. It is concluded that in addition to the intrinsic differences between species, the greater length of the test time for any species may result in increases bioaccumulation, metabolism, and detoxification of certain chemical classes. The relationships involving fish toxicity were moderately improved by the addition of a hydrophobic parameter.
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Duggan, Sam B. "Complex metal mixture reduces apparent protein carbonylation in a tolerant aquatic macroinvertebrate, Arctopsyche grandis." Thesis, Colorado State University, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=1606539.
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Mining is widespread and an economically important industry. Unfortunately, acid mine drainage (AMD) can pollute ecosystems with a cocktail of contaminants too complex for accurately forecasting its health consequences. However, through quantification of fundamental toxic events, the effects of complex mixtures can be observed. This project explored two potentially insightful and convenient endpoints. First, oxygen consumption (MO2), a well-established and sensitive indicator of respiratory impairment was utilized. Second, protein carbonyl content (PCC), an experimental ecological biomarker widely lauded in biomedical circles as a highly conserved indicator of health status was assessed for its utility in a metal tolerant aquatic macroinvertebrate, Arctopsyche grandis. A. grandis were exposed to eight environmentally relevant target concentrations (in duplicate) of AMD for eight days at a temperature controlled greenhouse containing artificial flow-through streams. As expected, MO2 was inversely related to treatment concentration (R 2=0.35, p=0.015). Protein carbonyl content, however, diverged from predictions. Protein carbonyl content analysis detected significantly more oxidative protein injury in control treatments than in metal-rich AMD treatments (p<0.001). Moreover, there was not a significant difference in PCC between different AMD concentrations. Protein carbonyl content’s departure from anticipated results likely is the consequence of dynamic interactions between direct and indirect effects at the chemical, biochemical, physiologic and behavioral levels. The results of this project illustrate flaws of utilizing a single biochemical marker to observe effects of a toxic mixture. Rather, a broad suite of biomarkers should be assayed to determine sublethal toxicity. These results also illustrates how multiple stressors can yield unanticipated outcomes.
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Cumming, Janet L. "Environmental Fate, Aquatic Toxicology and Risk Assessment of Polymeric Quaternary Ammonium Salts from Cosmetic Uses." Thesis, Griffith University, 2008. http://hdl.handle.net/10072/365855.
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The consumption of household and personal care products in Australia is similar to that of more highly regulated agricultural and veterinary chemicals. One class of chemical used in cosmetic applications, polymeric quaternary ammonium salts (polyquaterniums), is thought to have adverse effects on aquatic organisms. These polymers belong to a larger class of polymers, cationic polyelectrolytes, that are widely used in industry, largely for water treatment, and that have been extensively studied and regulated. The cosmetic polyquaterniums, however, have not been subject to the same scrutiny, even though differences in, or expectations of, their behaviour are known to exist. The aim of this study was to examine the fate and toxicity of some cosmetic polyquaterniums, and particularly to examine the impact of the presence of the anionic surfactant, sodium dodecyl sulphate, that is often complexed with the polyquaterniums in cosmetic formulations on fate and toxicity. The polyquaterniums studied consisted of six samples of Polyquaternium-10 of provided by Amerchol (The Dow Chemical Company, Midland, MI U.S.A.), five samples of three polyquaterniums (Polyquaternium-11, Polyquaternium-28, Polyquaternium-55) provided by International Specialty Products (ISP, Wayne, New Jersey, USA), and polydimethyldiallyl ammonium chloride (poly(DADMAC), Polyquaternium-6), widely used in water treatment but less commonly in cosmetic applications purchased from Sigma-Aldrich (Castle Hill, NSW, Australia). The four-step risk assessment paradigm (hazard identification, exposure assessment, hazard assessment, risk characterisation) provided the framework for this study. Metachromatic polyelectrolyte titration was used to analyse polyquaterniums in aqueous solution. Although the method is generally not viable in the presence of other ions due to interference, it was found to be viable in the presence of the anionic surfactant sodium dodecyl sulphate. Further, the method was found to work with the supernatant following a sorption experiment involving humic acid. It was not possible to titrate solutions following exposure to bentonite, or in solutions prepared for toxicity tests. Metachromatic Colloid Titration was found to be useful in determining the charge density of the polyquaterniums, and in measuring the concentration of polyquaterniums of known charge density. To establish the extent of exposure of vulnerable aquatic organisms to polyquaterniums released from cosmetic usage, it is necessary to estimate the concentration of polyquaterniums in the aquatic environment. The volume usage of polyquaterniums was estimated from available published data and standard emission scenarios used in the risk assessment of new and existing chemicals. The partitioning of the polyquaternium from the aqueous to the biosolid phase from wastewater treatment plants was estimated from the determination of the partition coefficient between water and humic acid. The latter was assumed to be a suitable surrogate for the biosolids. The fate of polyquaterniums in wastewater treatment plants was modelled using a fugacity approach based on a typical wastewater treatment plant. The import/manufacture volume of polyquaterniums for cosmetic uses was estimated to be between 20 and 60 tonnes per annum. The partition coefficient for polyquaterniums between the aqueous phase and humic acid was lower than expected, generally between 100 and 1000 for the polyquaterniums in this study. Fugacity modelling results suggested that the partitioning of polyquaterniums to the solid phase in wastewater treatment may be less than the default values normally assumed in regulatory risk assessment. Therefore, the estimate of the predicted environmental concentration (PEC) of polyquaterniums in Australian waters is between 0.7 µg/L and 40 µg/L depending on the assumptions and methodology used. Effects assessment, or hazard assessment, is concerned with determining the capacity of the cosmetic polyquaterniums to cause harm to aquatic organisms in the environment. In this study, the aim was to determine if the hazard of the polyquaternium from cosmetic usage is the same as that of the better studied water treatment polymers; and if the complexing of the polyquaternium with the anionic surfactant makes any difference to the toxicity. One species from each of three trophic levels, viz fish, crustacean and algae were selected. Using assessment factors developed for the risk assessment of new chemicals, the environmental concentration likely to be hazardous to the most sensitive species was estimated. The polyquaterniums studied were found to be just as hazardous to the most sensitive species for a typical cosmetic polyquaternium when complexed with the anionic surfactant. The lowest concentration at which a toxic effect occurred was for 50% growth inhibition for algae, 0.3 mg/L for the most toxic polyquaternium. With assessment factors, and using the concentration at which cosmetic polyquaterniums were likely to be hazardous to aquatic organisms, the predicted no effect concentration (PNEC) was estimated to be between 0.3 µg/L and 1.2 µg/L. The risk characterisation process combines the information obtained from the effects and exposure assessments to evaluate the nature of the potential risk. Commonly, the level of risk is estimated based on the PEC/PNEC ratio. In this study, using point estimates and probabilistic methods (Monte Carlo Simulation), the risk of polyquaterniums from cosmetic uses was estimated. Based on the behaviour and toxicity determined in this study, there may be some risk to aquatic organisms from individual polyquaterniums at even low import volumes. As a class of compounds, polyquaterniums from cosmetic uses may present a significant risk to environmental waters in Australia. Sensitivity analysis showed that the prediction of risk was most sensitive to those parameters for which the least amount of data was available, such as the import volume and dilution to receiving waters. A recently developed method of estimating potential risk based on the concept of an Environmental Threshold of No Concern (ETNC), was applied to the use of cosmetic polyquaterniums in Australia. Using the fugacity model approach, the usage volume at which the environmental concentration would exceed the critical threshold was estimated. The volume was found to be significantly lower than the estimated usage determined by either of the methods employed in estimating the current usage volume. While some problems remain in identifying the risk from polyquaterniums to the Australian environment, particularly those associated with the difficulties of quantifying polymers in environmental samples, this thesis has made substantial progress in the risk assessment. Particularly, it has been shown that the use of default assumptions that are largely unsubstantiated, and the sensitivity of the methodology to information that is often unavailable, may result in an estimation of risk that may not be able to protect vulnerable environments.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment
Faculty of Environment and Planning
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Child, P. "The toxicity of flue gas desulphurisation effluent to freshwater organisms." Thesis, University of Nottingham, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261111.
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Malaspina, Igor Cruz. "Eficácia biológica e feitos tóxicos de fontes de cobre e diquat para organismos aquáticos /." Jaboticabal, 2016. http://hdl.handle.net/11449/138219.
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Orientador: Silvano BiancoCoorientador: Robinson Antonio Pitelli
Banca: Lúcia Helena Sipaúba Tavares
Banca: Claudinei da Cruz
Banca: Silvia Patrícia Carraschi de Oliveira
Banca: Matheus Nicolino Peixoto Henares
Resumo: As macrófitas aquáticas possuem papel fundamental nos ecossistemas aquáticos participando dos processos de ciclagem de nutrientes, além de servirem como abrigo e alimento para muitas espécies de peixes e outros organismos. Dentre os principais métodos de controle de macrófitas está o controle químico com o uso de herbicidas. O objetivo deste estudo foi realizar o controle químico da macrófita Hydrilla verticillata com a aplicação isolada de diquat e hidróxido de cobre, e da mistura de diquat + 1% de hidróxido de cobre. O primeiro experimento para o controle da H. verticillata e da microalga Ankistrodesmus gracilis foi realizado em sala de bioensaio em recipientes plásticos de 1,5 litros, sendo todos os tratamentos testados eficientes no controle da macrófita e da microalga. Posteriormente, foram realizados experimentos em condições de microcosmos de concreto de 600 litros e em mesocosmos de concreto de 1200 litros, com o monitoramento de variáveis da qualidade da água (temperatura, oxigênio dissolvido, condutividade elétrica e pH), teor de clorofila a, demanda biológica de oxigênio (DBO) e demanda química de oxigênio (DQO) por um período de sessenta dias após a aplicação dos tratamentos. A mistura de diquat + 1% de hidróxido de cobre foi o tratamento mais eficaz no controle da macrófita Hydrilla verticillata para a maioria dos parâmetros analisados, havendo alteração nas variáveis de qualidade da água. Foram também realizados experimentos ecotoxicológicos para organismos não-... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: The macrophytes have a fundamental role in aquatic ecosystems participating in nutrient cycling processes, as well as serving as shelter and food for many species of fish and other organisms. Among the main weeds control methods is chemical control using herbicides. The aim of this study was the chemical control of the macrophyte Hydrilla verticillata with isolated application of diquat and copper hydroxide, and the mixture of diquat + 1% copper hydroxide. The first experiment for the control of H. verticillata and microalgae Ankistrodesmus gracilis was held in bioassay room in plastic containers of 1.5 liters, with all treatments tested effective in controlling macrophyte and microalgae. Subsequently, experiments were carried out under conditions of 600 liters concrete microcosms and in 1200 liters concrete mesocosms, with the monitoring of water quality variables (temperature, dissolved oxygen, electrical conductivity and pH), content chlorophyll a, demand biological oxygen (BOD) and chemical oxygen demand (COD) for a period of sixty days after the application of treatments. The mixture diquat + 1% copper hydroxide was the most effective treatment in Hydrilla verticillata of weed control for the majority of parameters, with change in water quality variables. Ecotoxicological experiments were also carried out for non-target organisms (Hyphessobrycon eques, Pomacea canaliculata, Lemna minor and Azolla caroliniana) with diquat, oxychloride and copper hydroxide, wherein the mix... (Complete abstract click electronic access below)
Doutor
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Harris, Graham. "A comparison of aquatic species responses to anticancer drug exposure." Thesis, Brunel University, 2015. http://bura.brunel.ac.uk/handle/2438/12731.
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To date, limited research has been conducted on the effects of cytotoxic drugs on aquatic species. Three of these species, a single celled plant, an invertebrate and a fish, were exposed to six cytotoxic drugs, both singly and as simple mixtures. A range of endpoints were assessed, including growth inhibition in algae, immobilisation in daphnia and the impact on organ size and the expression of the DNA damage repair genes RAD51 and p53 in zebrafish. No effects at environmentally relevant concentrations were observed in any of the three species.
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Jatar, Muriel M. "Assessing the Effect of Selenium on the Life-cycle of Two Aquatic Invertebrates: 'Ceriodaphnia dubia' and 'Chironomus dilutus'." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24036.
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Runoff and effluent discharge from mining activities has resulted in elevated concentrations of selenium in aquatic ecosystems. Bioavailability is dependent on chemical speciation. Although dissolved inorganic Se species are not directly toxic to organisms, uptake by primary producers and subsequent biotransformation to organo-selenium species substantially increase risk and bioaccumulation potential, potentially impairing reproduction in high-order organisms. The effects of dietary selenium exposure were assessed in two aquatic invertebrates: Ceriodaphnia dubia and Chironomus dilutus. Two generations of these organisms were exposed to seleniferous algae grown in 0-40 μg L-1 selenate. Dissolved selenate was readily absorbed and concentrated by algal species Pseudokirchneriella subcapitata and Chlorella kesslerii. Se had no effect on survival at treated concentrations. Dietary selenium exposures had little effect on reproductive endpoints in either invertebrate species, suggesting that invertebrates have the ability to regulate chronic Se exposures from dietary sources. These results provide valuable information concerning the effects of dietary selenium in aquatic invertebrates.
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Bourdon, Lisa Marie. "An integrative approach to characterizing the estrogenicity gradient of a portion of the South Platte River." Thesis, University of Colorado at Denver, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10112628.
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Endocrine disrupting compounds (EDCs) from agricultural, industrial, and municipal sources can be found in many surface waters with potential adverse implications for human and ecosystem health. The South Platte River represents a significant source of water for the Denver Metro Area, yet little data exists concerning EDCs. The aim of this study is to evaluate the occurrence and effects of EDCs downstream from two major wastewater treatment plants (WWTPs). This study characterizes the estrogenicity gradient of the South Platte River in the Denver Metro area by combining data from qPCR analysis for liver vitellogenin (vtg) mRNA with liver NMR metabolomics after a 5 day in situ caged exposure of fathead minnows. Concurrent water samples collected from the start and end times of the exposures were used to determine the occurrence and concentration of wastewater contaminants. Results found 68 of 122 chemicals downstream of WWTP 1 and 73 downstream of WWTP 2, including known EDCs (e.g. nonylphenol and octylphenol). A steroidal estrogen, estrone, was only found downstream of WWTP 2. Consistent with the highest measured concentrations of wastewater estrogens, the highest levels of vtg mRNA were measured downstream of WWTP 2. Metabolomics data coincided with vtg data and showed little variation except downstream of WWTP 2, where male polar metabolomes showed increased levels of alanine and glutamate, which are utilized in VTG synthesis. PCA of male polar metabolomes showed significant separation of WWTP 2 from WWTP 1 and the reference site, further supported by PLS-DA scores plot. Female polar metabolomes showed significant separation between WWTP 1 and WWTP 2 using PLS-DA scores plot. This study demonstrates that qPCR and metabolomics data can be reliably and concurrently used to illuminate impacts from chemical exposures, although further research will better elucidate target genes and metabolites of interest.
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Zhang, Wo Su. "Naphthenic Acids Disrupt Courtship in Silurana tropicalis." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/41148.
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Neuroendocrine processes coordinate the behavioural, physiological, and seasonal aspects of reproduction. Some chemicals can disrupt the hypothalamus-pituitary-gonadal axis, impacting reproductive health. Naphthenic acids (NAs), the carboxylic acids in petroleum, are of emerging concern as they contaminate coastlines after oil spills and aquatic ecosystems of the Athabasca oil sands area. They are acutely toxic in fish and tadpoles and possibly endocrine disrupting at sublethal levels. I characterized courtship behaviours and disruption by NAs in the Western clawed frog, Silurana tropicalis. Courtship primarily consists of males producing low trills and achieving amplexus, a mating position where a male clasps a female. Adult frogs were exposed for five days to 20 mg/L NA, a dose low enough to not affect physical activity. In males, absolute calling activity was reduced. Other acoustic parameters such as dominant frequency, click rate, and trill length were not affected. Injecting human chorionic gonadotropin had a slight rescue effect. Vocalization and amplexus were both inhibited after exposure and restored after 2 weeks of recovery. However, calling behaviour did not predict competitive ability or mating success. In females, NA exposure reduced mating success, possibly through decreased attractiveness or receptivity. Receptivity can be indicated by attraction towards the sound of mating calls (phonotaxis), which is cryptic and subjective. I created an apparatus that measures phonotaxis by placing speakers inside traps with infrared lights to detect the time of entry. This novel method is widely applicable for low-visibility observations and studies of choice and preference. This work shows that an aquatic contaminant can reduce mating success in otherwise healthy frogs, and provides a detailed foundation for further investigation.
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Webb, Diane. "Assessment of the health of the Swan-Canning river system using biochemical markers of exposure of fish." Curtin University of Technology, Department of Environmental Biology, 2005. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=16725.
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Most environmental studies concerning the environmental health of the Swan- Canning River system have focussed on nutrient inputs from both rural and urban catchments that are the cause of algal blooms. On occasions these algal blooms have resulted in fish deaths attributed to oxygen starvation. Relatively few studies have examined whether non-nutrient contamination is affecting the health of the riverine environment. Those studies that have, have concentrated on measuring the levels of heavy metals, organochlorines, organophosphates, and hydrocarbons in the sediments and water of the river system, and in the flesh of the biota. However, chemical analysis often fails to detect chemicals of concern due to high laboratory detection limits. In addition, analysis of the body burden of contaminants within biota does not necessarily convey if exposure is inducing adverse effects at the individual or ecosystem levels. The use of biochemical markers as a tool for the assessment of the health of the Swan-Canning River system was examined under a collaborative research project with the Waters and Rivers Commission, established in response to the recognition of the paucity of information from chemical analyses. The present study focussed on the estuarine portion of the Swan-Canning River system, using the black bream (Acanthopagrus butcheri), an estuarine dependent fish species, as a biomonitoring tool. Prior to the commencement of this study it had been determined that the black bream was a suitable fish species for use as a biomonitoring tool when using mixed function oxygenase (MFO) activity induction under laboratory conditions.Biopsies taken from feral black bream collected from eight sites during the period 2000 to 2002 from the estuary confirmed that the use of MFO induction in this fish species as a biomarker of exposure to organic contaminants is a reliable biomarker. Fish gender was a confounding factor in the interpretation of MFO induction when using the enzyme ethoxyresorufin-O-deethylase (EROD) as EROD activity was suppressed in both pre- and post-spawning female black bream. No such suppression was identified when using the MFO enzyme ethoxycoumarin-O-deethylase (ECOD). However, due to differences in the pattern and intensity of the induction of EROD and ECOD activities it was concluded that ECOD activity was not a substitute for EROD activity to detect certain chemical as ECOD activity represents a different cytochrome P450 pattern to EROD activity. No spatial, seasonal or interannual differences in the level of the enzyme sorbitol dehydrogenase (SDH) in the blood of the black bream were measured indicating that the interpretation of MFO activity induction was not compromised by hepatocellular damage. This study has shown that the black bream in the Swan-Canning Estuary are exposed to, and are metabolising polycyclic aromatic hydrocarbons (PAHs), notwithstanding that the chemical analysis of the contaminant load of these substances in the estuarine waters is consistently below laboratory detection limits. In addition, biomarker responses such as ECOD activity indicate that various other organic pollutants are present and are being metabolised by the black bream.
The measurement of biliary metabolites clearly show that, under winter conditions, the comprehensive drainage system of the Swan Coastal Plain contributes PAHs from pyrogenic sources such as burnt fuels into the estuary although the onset and intensity of rainfall events notably impacts on the volume of stormwater inflow. During the summer months, when freshwater flow is minimal, petrogenic sources of PAHs are dominant. Metabolic enzyme analysis points to the black bream being challenged in their aerobic capacities during summer, and that gill tissue was the most suitable tissue to evaluate the aerobic and anaerobic capacity of this fish species. Furthermore, there was a significant negative correlation between stress protein (hsp70) expression and DNA integrity in field-collected fish suggesting that the black bream within the estuary are highly stressed. No gradient of response in biomarker levels was identified in the Swan-Canning Estuary under either winter or summer conditions indicating there are multiple sources of inputs of potential pollutants along the length of the estuary. Stormwater and road runoff are the primary source of pollutant input into the estuary in the winter months, while summer biomarker levels, particularly PAH, appear to reflect the high usage of the estuary for recreational purposes and runoff from poorly irrigated parks and gardens. Significant rainfall events at any time of the year have the potential to adversely impact the biota of the estuary, particularly when these events result in a flush of water from the drains following long dry periods.
The study shows that the black bream is a suitable fish species to use under field conditions to detect the presence of bioavailable non-nutrient contamination within the Swan-Canning Estuary. A suite of biomarkers in black bream have been tested seasonally and annually but only a small number of biomarkers have proven suitable for routine monitoring of the health of the Swan-Canning Estuary. This treatise concludes with several recommendations for further investigations into biomarkers of fish health for the purpose of increasing our understanding on the sources and type of contamination entering the estuary, and potential effects on the aquatic biota of the Swan-Canning River system. These recommendations include, but are not limited to: (1) the need to determine baseline levels for the different biomarkers investigated in this study, (2) the examination of the Moore River or the Warren River estuaries as potential reference sites for biomarker studies in the Swan- Canning Estuary, (3) the advantage of identifying a second estuarine-dependent indigenous fish as a biomonitoring tool, (4) the requirement for a targeted study aimed at clarifying the relationship between major drain discharges, biomarker levels and impacts on river biota, and (5) a study of estuarine waters utilising SPMDs be undertaken in tandem with biomarker analysis of field captured fish would be beneficial.
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O'Reilly, Kirk Thomas. "The role of copper in the apparent aluminum toxicity of aquatic systems." PDXScholar, 1985. https://pdxscholar.library.pdx.edu/open_access_etds/3522.
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The effect of variations in aluminum and copper concentrations on the growth rate and enzyme activity of the green alga Scenedesmus quadricauda was investigated. The goal was to determine which chemical species control the biological parameters. The computer program MINEQL (Westal et al 1976) was used to estimate chemical speciation. In the prevalence of both metals, algal growth rate and alkaline phosphatase activity could be correlated to cupric ion activity. The activity of isolated bacterial alkaline phosphatase was found to be a function of both total copper concentration and cupric ion activity. A model was developed to predicted the effects on alkaline phosphatase of perturbation in aquatic chemistry.
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Koesoemadinata, Santosa. "Aquatic toxicology of selected rice insecticides, with special reference to their effects on fish culture in West Java, Indonesia." Thesis, University of Stirling, 1990. http://hdl.handle.net/1893/3530.
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Insecticides are widely used in SE Asian countries to control insect pests in rice, mainly stemborers (Chilo suppresallis) and brown plant hoppers (Nilaparvata lugens). The use of highly toxic insecticide compounds, however, is known to cause serious problem for fish culture in wet rice fields in many of these countries, particularly in Indonesia where this practice assumes a tremendous "house hold economic" importance, as well as being an essential part of the nation's inland aqua-culture production system. The laboratory and field experiments described were carried out to establish whether the application of five selected rice insecticides (fenobucarb, isoprocarb, buprofezin, diazinon and alphamethrin) would influence the growth and production of common carp fingerlings (Cyprinus carpio LINN.) raised in wet rice fields. Laboratory static toxicity tests revealed that the carbamate insecticides (fenobucarb and isoprocarb) were the least toxic insecticide compounds. The 96 hour Median Lethal Concentration (i.e the concentration that killed 50% of the test fish in 96 hours exposure period, under specified conditions) of these insecticides were 5.8mgl-1 and 5.3mgl-1, respectively. The synthetic pyrethroid insecticide alphamethrin was the most toxic insecticide with 96h-LC50 of 0.037mg1-1, while the organophosphate diazinon and the thiadiazin buprofezin showed intermediate toxicity to common carp (96h-LC50 = 2.3mgl-1 and 1.5mgl-1, respectively). A series of five field experiments were consecutively conducted, using 24 specially constructed rice field plots to accomodate the culture of common carp fingerlings for a period of 21 days. A single application of three dose regime, i.e 1/2X, 1 X and 2X of the recommended dose rate for insect control was given as treatment in each experiment. The survival of fish in all experiments were not significantly influenced by the insecticide treatment (P > 0.05). The growth rate and the production of fish biomass in rice fields treated with isoprocarb, buprofezin, diazinon and alphamethrin, were also found to be comparable with those in the untreated control plot (P > 0.05). In the rice fields treated with the highest dose rate of fenobucarb (1500gha-1 ,Al), the growth and production of fish were significantly lower than those in the untreated control rice fields (P < 0.05). Observations on the rice field biota revealed no definite pattern in the temporal changes of the population of zooplankton and macroinvertebrates both in the insecticide treated plots as well as in the untreated control plots. The minimum effects of the insecticide treatment to fish and rice field biota observed in the experiment were presumably due to several factors, mainly because a significant amount of the compounds were adsorbs by the rice field soil and aquatic vegetations and not onto the water, causing less toxicity, followed by the rapid flushing of the chemicals from the rice field system. The composition of the diet of common carp fingerlings in the rice field was found to be similar with those reported in the natural ponds, consisting mainly of aquatic insects (and their larvae), crustaceans, benthic macroinvertebrates and plant detritus. Based on the results of the present experiments, of the five insecticide compounds tested, diazinon and fenobucarb appeared to produce greater risk to fish when used in rice-fish farming. The use of agrochemicals in rice-fish farming should be carefully managed and controlled, using selected low toxic and non-persistent insecticides based on the result of laboratory and field toxicity tests.
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Martinez, Cynthia Therese 1969. "Selenium levels in selected species of aquatic birds on Imperial National Wildlife Refuge." Thesis, The University of Arizona, 1994. http://hdl.handle.net/10150/278452.
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Five species of waterbirds were collected from five sites on Imperial National Wildlife Refuge between April and August of 1993. There were previous baseline contaminants data for all sites. Sites were of two distinct habitat types. Backwater lakes have a direct connection to the mainstem of the Colorado River, and seep lakes receive river water only via seepage through the soil column. Selenium concentrations in liver, kidney, and muscle tissues were consistently higher in birds collected from backwater lakes than those collected from seep lakes. Eighty-one percent of the birds collected on backwater lakes (n = 52) were above the effect threshold for reproductive impairment or embryotoxicity (10 ppm dry weight in livers). Herbivorous birds had significantly (p ≤ 0.05) lower tissue selenium levels than those species feeding on animal matter. Of the birds feeding on fish and invertebrates, 83% (n = 47) had selenium levels in liver above the effect threshold. Differences in selenium concentrations based on diet suggest food chain cycling of selenium. Eggs from waterbirds as well as those from neotropical migrants were above the 3 ppm embryotoxicity threshold.
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Belanger, Scott E. "Functional and pathological responses of selected aquatic organisms to chrysotile asbestos." Diss., This resource online, 1985. http://scholar.lib.vt.edu/theses/available/etd-05222007-091305/.
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Stanley, Jacob K. Brooks Bryan William. "Effects of chiral contaminants to aquatic organisms pharmaceuticals as model compounds for enantiomer specific ecological hazard assessment /." Waco, Tex. : Baylor University, 2006. http://hdl.handle.net/2104/5104.
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Chapman, Kimberly K., Michael J. Benton, Ralph O. Brinkhurst, and Phillip R. Scheuerman. "Use of the Aquatic Oligochaetes Lumbriculus Variegatus and Tubifex Tubifex for Assessing the Toxicity of Copper and Cadmium in Spiked-Sediment Toxicity Bioassay." Digital Commons @ East Tennessee State University, 1999. https://dc.etsu.edu/etsu-works/2881.
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A sediment toxicity test using the freshwater oligochaetes Lumbriculus variegatus and Tubifex tubifex was performed. We evaluated acute and chronic toxicity affects of copper and cadmium on reproduction in both species and the bioaccumulation of both metals by L. variegatus using artificial sediment. L. variegatus bioconcentrated copper 22‐fold and cadmium 16‐fold after a 14‐day exposure to spiked artificial sediments with 0.02% organic content. The EC50 for T. tubifex varied depending upon endpoint from 2.7 to 2.8 mg/L for cadmium and from 8.4 to 8.9 mg/L for copper. The EC50 for L. variegatus was 2.2 mg/L for cadmium and 3.9 mg/L for copper. Based on these results, L. variegatus appears to be more sensitive to metal toxicity in artificial sediments than T. tubifex.
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Dobbins, Laura L. Brooks Bryan William. "Chemical toxicity distributions in aquatic toxicology relative sensitivities of estrogenicity assays and ecotoxicity of parabens in model freshwater organisms /." Waco, Tex. : Baylor University, 2009. http://hdl.handle.net/2104/5350.
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Lahman, Sara Elisabeth. "The Ecotoxicological Impacts of Copper in Aquatic Systems." Bowling Green State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1427119997.
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Arnolds, Judith Lize. "Oxidative stress responses in the aquatic macrophyte, Ceratophyllum Demersum L., as biomarkers of metal exposure." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2649.
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Thesis (DTech (Environmental Health))--Cape Peninsula University of Technology, 2017.Metal pollution in aquatic environments is considered a major environmental concern because of variation in several abiotic factors that impose severe restrictions on organisms living in these areas. Ceratophyllum demersum L. (family Ceratophyllaceae), a hornwort or coontail, free floating rootless macrophyte has been suggested a suitable model for investigating metal stress and was used in the current study. This study assessed the use of selected biological responses, namely antioxidant responses and changes in chlorophyll concentration in Ceratophyllum demersum L., as biomarkers of metal exposure, and also investigated the field application of these responses in the Diep River. The ultimate aim was also to determine the usefulness of C. demersum as model of metal contamination and as phytoremediator after a pollution event. An investigation of metal bioaccumulation in this macrophyte exposed to different concentrations of a combination of metals over a five-week exposure period in a greenhouse, was undertaken, as well as a field study in the Diep River, Milnerton, Cape Town and a pond (reference site) at the Cape Peninsula University of Technology, Cape Town, to validate experimental results. In the laboratory study the water was contaminated once off at the beginning of the study, to simulate a pollution event. The metal concentrations in the water and plants were measured in the four treatments and the control every week over a five-week exposure period. The samples were acid-digested and analysed with an Inductively-Coupled Plasma-Mass Spectrophotometer (ICP-MS). The results showed that concentrations of the metals in the water varied in all treatments over time with no specific patterns amongst the treatment groups. This macrophyte proved highly effective in the bioaccumulation of these metals at all four exposure concentrations. The metals bioaccumulated rapidly in the plants after the water was spiked. The main focus of the study was to investigate the possible use of biochemical responses in C. demersum as possible biomarkers for metal exposure. A range of antioxidant/oxidative stress parameters were measured in the plant exposed to a combination of metals (Al, Cu, Fe, Zn) in four different treatments over the five week exposure period. Total antioxidant capacity (TAC) was measured using Total Polyphenols (TP), Ferric Reducing Antioxidant Power (FRAP) and Oxygen Radical Absorbance Capacity assay (ORAC), enzyme activity was determined using Catalase (CAT), Superoxide Dismutase (SOD), Ascorbate Acid (AsA) and Total Glutathione (GSHt) and lipid peroxidation was measured by using Thiobarbituric Acid Reactive Substances (TBARS) and Conjugated Dienes (CDs). The cocktail of the four metals induced significant changes in the antioxidant defence system of C. demersum, including the antioxidant enzyme activities. The different metal exposures disturbed the cellular redox status in the plant. The current study has demonstrated that this macrophyte shows tolerance to metal-induced oxidative stress and that it can survive under relatively high concentrations of these metals by adapting its antioxidant defence strategies. Chlorophyll was extracted in 80% chilled acetone in the dark and the absorbance values were determined using a spectrophotometer. Chlorophyll a (chl a), chlorophyll b (chl b) and total chlorophyll (chl t) contents were measured under different exposure concentrations of metals in the macrophyte. The results of this study indicated that chlorophyll contents were variable over the exposure period and no significant differences in chlorophyll concentrations were found between weeks. A field study in the Diep River and the pond located at the CPUT campus (reference site) was conducted to validate experimental results. Plants in a polluted section of the Diep River were shown to bioaccumulate metals to high concentrations. Bioaccumulation of metals in C. demersum might have induced oxidative stress, and other environmental factors such as temperature- and chemical stress might have caused chlorophyll degradation. The chlorophyll concentrations in the plants of the pond (reference site) might also have been affected by temperature and chemical stress of the water. Significantly higher AsA, CAT, ORAC, SOD and TBARS concentrations in the Diep River plants might be an indication that the plants in the river might be well adapted to the constant exposure to metals and that the plants might have developed a tolerance mechanism to cope with oxidative stress compared to those of the pond. The results show that metals are bioaccumulated quickly by C. demersum after the water is contaminated with metals, i.e. after the "pollution event". However, over time, metals are continuously exchanged between the plants and the water, accounting for the fluctuations in metal concentrations observed over time. This study has shown that C. demersum has phytoremediation potential because it was able to remove high concentrations of metals from the contaminated water. Therefore, C. demersum, can be applied as a model for metal contamination and a phytoremediator after a pollution event. The potential to antioxidant responses and chlorophyll content as biomarkers of metal exposure in C. demersum have been demonstrated.
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Halffman, Willem. "Boundaries of regulatory science eco/toxicology and aquatic hazards of chemicals in the US, England, and the Netherlands, 1970-1995 /." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2003. http://dare.uva.nl/document/67455.
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Cregger, S. S., and Phillip R. Scheuerman. "A Rapid Biochemical Test Using Cell Lines for Measuring Chemical Toxicity in Aquatic Systems." Digital Commons @ East Tennessee State University, 1993. https://dc.etsu.edu/etsu-works/2896.
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Smith, Abraham Jeffrey. "Development and Application of Aquatic Toxicology Studies for the Assessment of Impacts Due to Chemical Stressors Using Non-Standard Indigenous Organisms." FIU Digital Commons, 2018. https://digitalcommons.fiu.edu/etd/3709.
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Research in the multidisciplinary science of ecotoxicology is crucial to assess injuries to ecosystem resources from chemical spills or other stressors used to support environmental decision-making. Established guidelines recommend the use of non-standard native species in toxicity investigations. This work focused on the use of native species for aquatic toxicity assessment to make more relevant conclusions on the potential for adverse biological effects to occur as a result to single chemical exposures or exposures to a complex mixture like oil. We apply these studies to investigate petroleum product impacts from the Deepwater Horizon incident and concerns for metal toxicity in estuarine environments using a new model organism. Data generated from comprehensive toxicity testing programs were used in the first probabilistic risk assessment of Deepwater Horizon oil toxicity highlighting a lack of appropriate data and representative phyla. Novel toxicity study methods and a stress-response index were developed and demonstrated sensitivity and success in using the starlet anemone in ecotoxicology studies. Swim performance was used as new method to investigate sublethal indicators of stress resulting in varied responses from sheepshead minnows and Florida pompano. These studies further our ability for better laboratory-to-field extrapolation and for decision-making. The use of native species and complex mixtures like oil presented novel challenges in conducting aquatic toxicity studies. Special emphasis is placed on the necessity to understand the appropriate laboratory conditions for native species not typically held in the laboratory and maintaining study parameters to obtain quality data for more accurate interpretation and replication.
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Albanese, Katie. "Photochemistry and Toxicity of Triclosan, Triclocarban, and their Photoproducts and Mixtures in Freshwater Systems." The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1468967416.
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Binder, Markus. "An evaluation of recirculating artificial stream designs for acute toxicity testing using two South African Ephemeroptera species exposed to sodium sulphate." Thesis, Rhodes University, 2000. http://hdl.handle.net/10962/d1005376.
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Three artificial stream designs, termed Large Artificial Stream Units (LASUs), Raceways, and Channels, at two major scales (1700 L, 12.5 L and 20 L recirculated volume) were developed at the Institute for Water Research, Rhodes University, Grahamstown, in order to explore the possibilities of using indigenous rheophilic macroinvertebrates in routine toxicity tests. This study compared these systems, using 96h-EC50 values from sodium sulphate toxicity tests as the experimental response. Two local Ephemeroptera (Leptophlebiidae: Adenophlebia auriculata Eaton, and Baetidae: Afroptilum sudafricanum Lestage) were evaluated for their suitability in routine toxicity tests; and the possible effects of elevated salinity levels in South African rivers on the test species were assessed. Two sets of experiments with each mayfly species were conducted, following an unreplicated regression design. Dechlorinated tap water was used as the water source. Experiments in the Channels were repeated to determine experimental variability. Results were compared statistically by testing for overlap of 95% confidence limits (95%Cls) of EC50 values. The differences between A. auriculata EC50 values in the different systems were statistically significant (no overlap of 95%CLs), but they were not more variable than has been considered normal for biological systems (Coefficient of variation 20.1 %; ratio of greatest EC50 / smallest EC50 1.63). The differences were not related to the scale or the average current velocity characteristic of each stream design (average current velocity LASUs - Raceways - Channels 0.090 - 0.083 - 0.038 m/s). The Channels proved to be most efficient with regard to practical performance as they are portable and easily transportable, user-friendly, reliable, splash-free, cost effective to construct, and can easily be adapted to specific requirements. These systems are therefore recommended for regular use. The suitability of the two mayfly species for routine toxicity testing was evaluated. A. auriculata EC50 values showed a significant negative correlation with the corresponding average body-size (range 1476 - 1610 μm, mean 1555 μm). The different average body-sizes probably reflected the abundance of a certain size range present in the Palmiet River at the time of collection. Both species reacted similarly to Na₂S0₄ (similar slopes of the toxicity curves), identifying this salt as a slow acting toxicant. A. sudafricanum populations were more sensitive to Na₂S0₄ (EC50 3.404 g/L) than A. auriculata (EC50 8.090 g/L), probably because of its smaller body-size (mean 709 μm) and a lack of extremely tolerant individuals. In comparison to other freshwater macro invertebrates, including the standard toxicity test organism Daphnia spp., both mayfly species seemed to be moderately tolerant of Na₂S0₄; therefore there was no particular advantage to using these indigenous taxa rather than Daphnia spp. An assessment of the effects of elevated salinity/TDS levels on the test taxa yielded preliminary insights. A NaCI-EC50 for A. sudafricanum could be extrapolated and suggested a higher sensitivity to Na₂S0₄ than to NaCl. When Na₂S0₄ EC50 values of both species were compared to selected TDS levels of South African rivers, 4. auriculata would mostly not be affected, but A. sudafricanum might occasionally suffer from sub-lethal effects, depending on the sulphate proportion of the TDS. The South African guideline for TDS seemed to protect both species sufficiently.
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Moraes, Joelma Crespo. "Efeitos do Thiodan® (endosulfan) nas brânquias de Astyanax aff. bimaculatus." Universidade Federal de Viçosa, 2011. http://locus.ufv.br/handle/123456789/5085.
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Previous issue date: 2011-08-04One of the factors most relevant in environmental pollution that involves the ecosystem is the contamination by pesticides, especially when these are applied indiscriminately. Between these compounds are pesticides with several chemical compositions that are used with different aims. The aquatic environment has been considered the most relevant toxic receptor compartment, and so has attracted attention of researchers for evaluation of biological indicators. Thus, it becomes necessary to use methods of assessment of the effects of pollutants using fish to show the first signs of environmental stress caused by contaminants in different levels of biological organization. The morphological disorders in fish organs with wide surface area exposures to the environment, such as the gills, may be useful as biomarkers. The Thiodan® (Bayer), an insecticide and acaricide widely used to control chewing and sucking insects was chosen for this study. The use of small species, such as lambari Astyanax aff. bimaculatus, facilitates the execution of laboratory tests, reason for the choice of these species. This study determined the LC50-96h with 120 animals, divided in one as control group and seven concentrations of Thiodan® (1.5, 3, 6, 12, 24, 48 and 96 μg.L-1) with three replicates of five fish each. Also it has been evaluated the influence of Thiodan® on the morphology of the gills of female A. bimaculatus. The fish were distributed in four separate experiments (fish without adaptation and without food, fish without adaptation and fed, fish adapted and without food, and fish adapted and fed). For each experiment were used a control group and three concentrations of Thiodan® (1.3, 2.6 and 5.2 μg.L-1) lasting 96 hours, with three replicates of 10 fish in each aquarium. For morphological and morphometric studies, fragments of gills were processed following routine techniques. The water quality was measured and was according to the Resolution 357/2005 (CONAMA). The result of LC50-96h was 13.6μg.L-1 with a confidence interval from 10.1 to 18.4μg.L-1 (P<0.05). During the toxicity tests (96h) the exposed groups showed aggressive behavior and escape attempt in the highest concentration (5.2μg.L-1), restlessness, erratic swimming and branchial hyperventilation at all concentrations in four experiments. Histologically there was hyperplasia, lamellar fusion, detachment and destruction of the lamellar epithelium. The morphometric analysis showed a reduction of number and diameter of chloride cells, the thickness of the primary lamellae, and the length of the secondary lamellae, within and between experiments (P<0.05). It was observed an increase in the number of mucus cells and coincident points with the gill tissue (P<0.05) in the highest concentration (5.2μg.L-1) in experiments 1 and 2. There was an increase (P<0.05) in the diameter of the aneurysm in the experiment 1 when compared to the others. There was no difference (P>0.05) in the diameter of mucus cells, vasodilation, and the amount of the hemorrhage focus between the experiments. Morphometric analysis showed that changes in experiment 1 were more evident when compared to others. Based on these results the experiment showed that the gills of A. bimaculatus can be used as biomarkers of environmental contamination by Thiodan® but the fish should not be used as bioindicator organism, because it has low sensibility to this product.
Um dos fatores de maior relevância na poluição ambiental e que compromete um ecossistema é a contaminação por agrotóxicos, principalmente quando esses são aplicados de forma indiscriminada. Entre esses compostos estão pesticidas que possuem diferentes composições químicas e são utlizados com diversas finalidades. O ambiente aquático tem sido considerado o mais relevante compartimento receptor de tóxicos, e por isso tem despertado interesse de pesquisadores para avaliação de indicadores biológicos. Assim, torna-se necessário a aplicação de métodos de avaliação dos efeitos dos poluentes utilizando peixes para demonstrar os primeiros sinais de estresse ambiental causados por contaminantes em diferentes níveis de organização biológica. As alterações morfológicas dos órgãos de peixe com grande superfície de exposição ao meio ambiente, como as brânquias, podem ser úteis como biomarcadores. O Thiodan® (Bayer), um inseticida e acaricida amplamente utilizado para o controle de insetos chupadores e mastigadores, que apresenta ação por contato e ingestão, foi escolhido para o presente estudo. O uso de espécies de pequeno porte, como o lambari Astyanax bimaculatus facilita a execução dos testes em laboratório, motivo da escolha da espécie. O presente trabalho determinou a CL50-96h e avaliou a influência do Thiodan® (Bayer) sobre a morfologia das brânquias de fêmeas da A. bimaculatus em maturação gonadal. Foram utilizadas 600 fêmeas de lambaris, divididas em cinco lotes, que permaneceram em sistema estático para determinação da CL50-96h e para o teste de toxicidade. O primeiro lote de 120 animais, utilizado para a determinação da CL50-96h, foi constituído de três repetições com cinco peixes cada para o grupo controle e para cada concentração de Thiodan® (1,5; 3,0; 6,0; 12,0; 24,0; 48,0 e 96,0 μg.L-1). Os demais lotes foram distribuídos em quatro experimentos distintos (peixe sem adaptação e sem alimentação, peixes sem adaptação e alimentados, peixes adaptados e sem alimentação, e peixes adaptados e alimentados). Para cada experimento, utilizou-se um grupo controle e três diferentes concentrações de Thiodan® (1,3; 2,6 e 5,2μg/L), com três repetições de 10 peixes cada, durante 96h. Para estudos morfológicos emorfométricos, fragmentos de brânquias foram processados seguindo técnicas de rotina. Os parâmetros indicadores da qualidade da água utilizada para a realização dos experimentos encontraram-se em conformidade com as condições exigidas pela Resolução 357/2005 (CONAMA) para cultivo e criação de peixes tropicais. A CL50-96h obtida foi de 13,6μg.L-1 com intervalo de confiança de 10,1 a 18,4μg.L-1 (P<0,05). Durante os testes de toxicidade (96h), os grupos expostos apresentaram comportamento agressivo e tentativa de fuga na maior concentração (5,2μg.L-1), agitação, nado errático e hiperventilação branquial em todas as concentrações nos quatro experimentos. Histologicamente observou-se hiperplasia, fusão lamelar, descolamento e destruição do epitélio lamelar. As análises morfométricas mostraram redução de número e diâmetro de células de cloreto, da espessura das lamelas primárias, e do comprimento das lamelas secundárias, entre e dentro dos experimentos (P<0,05). Também foi observado aumento do número de células de muco e dos pontos coincidentes com o tecido branquial (P<0,05) na maior concentração (5,2μg.L-1) nos experimentos 1 e 2. Houve aumento (P<0,05) no diâmetro de aneurisma no experimento 1 em relação aos demais. No diâmetro de células de muco, na vasodilatação e na quantificação de foco de hemorragia entre os experimentos não houve diferença (P>0,05). A análise morfométrica mostrou que as alterações no experimento 1 (animais sem adaptação e sem alimentação) foram mais evidentes quando comparadas aos demais. Com base nesses resultados, pode se concluir que as brânquias de A. bimaculatus podem ser utilizadas como biomarcadores de contaminação ambiental pelo Thiodan®.
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Huerta, Buitrago Belinda. "Pharmaceuticals and endocrine disruptors: accumulation in aquatic biota and environmental effects." Doctoral thesis, Universitat de Girona, 2016. http://hdl.handle.net/10803/402946.
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Occurrence, fate, and adverse effects of emerging contaminants in the aquatic environment have become a matter of concern, since these compounds have been persistently detected in wastewater treatment plant (WWTP) effluents, surface water, seawater and groundwater all over the globe. The incessant release of emerging contaminants into freshwater ecosystems could affect a broad variety of organisms: from bacterial communities to fish, as well as aquatic plants and insect larvae. The present thesis aimed to investigate the potential bioaccumulation and biomagnification of two groups of emerging contaminants − pharmaceuticals and endocrine disruptors − in aquatic biota, including fish, invertebrates and river biofilm in the natural environment. A second aim of this thesis was to evaluate the impacts of exposure to some of these contaminants in the organisms, and the possible relation between bioaccumulation and toxicological effects.La presència, destí i efectes adversos dels contaminants emergents en el medi aquàtic s’han convertit en un tema de preocupació general ja que, aquests compostos, s’han estat detectant de manera persistent en els efluents de les Estacions Depuradores d’Aigües Residuals (EDAR) així com en aigües superficials, marines i subterrànies de tot el planeta. La constant presència de contaminants emergents en el medi aquàtic continental podria afectar a una gran varietat d’organismes: des de comunitats bacterianes fins a peixos, així com a plantes aquàtiques i larves d’insectes. El primer objectiu d’aquesta tesi doctoral és investigar la potencial bioacumulació i biomagnificació de dos grups de contaminants emergents –fàrmacs i disruptors¬ endocrins– en la biota aquàticaincloent peixos, invertebrats i biofilm. El segon objectiu és avaluar els possibles impactes que l’exposició a aquests contaminants poden tenir en els organismes i establir la possible correlació entre bioacumulació i efectes toxicològics.
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Gendusa, Tony C. "Toxicity of Chromium and Fluoranthene From Aqueous and Sediment Sources to Selected Freshwater Fish." Thesis, University of North Texas, 1990. https://digital.library.unt.edu/ark:/67531/metadc330672/.
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Research efforts in aquatic toxicology have historically centered on the chemical analyses and toxic effects of waters to aquatic organisms. More recently, sediment-source toxicity has been explored, with efforts concentrated on establishing sensitive and accurate methodologies. This study focused on the toxicity of trivalent chromium, hexavalent chromium, and fluoranthene to Pimephales promelas, Ictalurus punctatus, and Lepomis macrochirus. Test fish were exposed to both water-borne and sediment-source toxicants for 96 hours (h) and 30 days (d). A 96-h and 30-d LC50 (mg/L Cr, ug/L Fluoranthene) was determined for each fish species exposed to aqueous toxicants. In addition, 96-h and 30-d LC50s were determined for each fish species from sediment chromium concentrations (mg/kg) and sediment fluoranthene concentrations (ug/kg). Although lethality endpoints were used throughout this research, acute effects other than mortality were determined for Lepomis macrochirus exposed to hexavalent chromium. Lethal toxicity values (96-h and 30-d LC50 and their 95% confidence limits) for trivalent chromium could not be determined since trivalent chromium concentations above 6.0 mg/L could not be obtained at water pHs compatible with these fish species. Trivalent chromium addition to test waters at pHs compatible with fish survival resulted in a chromium precipitate that was not lethal to test fish. In contrast, fathead minnows, channel catfish, and bluegill sunfish exposed to hexavalent chromium in water and sediments experienced mortality. Fathead minnows exposed to fluoranthene in water for 96h demonstrated a maximum mortality of 69%, while 100% mortality was achieved with channel catfish in similar tests. Sediment tests with fluoranthene resulted in 100% mortality with both fathead minnows and channel catfish.
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Mennigen, Jan A. "The Serotonergic System as a Target for Neuroendocrine Disruption in the Brain of Goldfish (Carassius auratus)." Thèse, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/19927.
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Serotonin stimulates reproduction and inhibits feeding/growth in the neuroendocrine brain of goldfish. The objective of this thesis is to study the effects of selective serotonin
reuptake inhibitor pharmaceuticals (SSRIs) on these systems, as SSRIs, such as fluoxetine, are detected in effluent and bioconcentrate in the brain of wild fish. Genes of the serotonin system were cloned to identify molecular conservation, seasonal expression, and tissue distribution. The serotonin transporter, the target molecule of fluoxetine, was highly conserved and ubiquitously expressed in goldfish. Seasonal changes of hypothalamic gene expression of the serotonin transporter support a role in the seasonal modulation of both processes. Fluoxetine injection experiments were used to assess effects on reproductive endpoints and to identify molecular mechanisms in the neuroendocrine brain. Fluoxetine inhibited serum estradiol concentrations in female goldfish and decreased isotocin mRNA abundance in the hypothalamus and telencephalon. Isotocin injections stimulated circulating estradiol concentrations, providing a causal link. Evidence for an involvement of serotonin in isotocin regulation was investigated using immunocytochemistry and 5-HT1A receptor agonists and antagonists. A close proximity of
serotonin fibers and isotocin cell bodies and fibers was found in the telencephalon and pituitary,respectively. Injection of a 5-HT1A receptor antagonist inhibited isotocin mRNA expression in the telencephalon. Identified gene targets were investigated in waterborne fluoxetine exposures,including environmental concentrations. Waterborne fluoxetine led to a reduction in basal and pheromone-stimulated milt volume in male goldfish. Gene expression evidence indicated a central inhibitory effect of fluoxetine through the decrease in mRNA abundance of follicle-stimulating hormone in the pituitary and isotocin in the telencephalon. Feeding rate and weight decreased in fluoxetine-injected goldfish, indicating an anorexigenic effect. Fluoxetine induced changes in the gene expression of the feeding peptides neuropeptide Y, corticotropin-releasing factor, and cocaine- and amphetamine-regulated transcript-I in the hypothalamus and telencephalon. Waterborne exposure to fluoxetine validated the anorexigenic effect in goldfish and was correlated with increased expression of corticotropin-releasing factor mRNA, an anorectic peptide. The thesis provides evidence for disrupting effects of fluoxetine on neuroendocrine control of reproductive
function and feeding/growth in goldfish, partially at environmental concentrations. The thesis provides the framework for the investigation of existing aquatic contaminants which modulate the serotonin system.
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Thomas, Carolyn L. "Development of a test system for screening toxic substances: a comparison using organic substances." Diss., Virginia Polytechnic Institute and State University, 1985. http://hdl.handle.net/10919/49941.
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The purpose of this research was to develop a test system for screening toxic substances by predicting their aquatic ecosystem effects. The system studied was a static, one liter microcosm with a diverse species assemblage. Teh microcosm was composed of biotic inoculum, chemically defined medium and sediment. The biotic inoculum cotained primary producers, grazers, carnivores and decomposers. The chemical medium used was Taub #82 modified by adding sodium bicarbonate. Three different types of sediment were studied: sand, clay and clay plus sand.
Four organic chemicals: phenol, triethylene glycol (TEG), quinoline and naphtoquinone were evaluated with this test system. The toxicities of TEG, quinoline and naphthoquinone were compared for each sediment type. Toxicity was evluated in terms of the chemicals' effects on primary productivity and heterotrophic activity though other effects are also noted. The toxicity of the chemicals in this study was compared to those from other toxicological evaluations based on threshhold toxicity values (EC20 and LC50).
The screening test sytem evaluated in this study did not demonstrate significanly different threshhold toxicity values than the other screening systems to which it was compared. The ranking of the toxicants based on EC20 values was different for the two ecosystem properties, net production and heterotrophic activity. Naphthoquinone concentration exhibited no correlation between ecosystems property values and therefore, could not be ranked. Phenol exhibited the greatest toxicity to net production immediately after the toxicant addition. Quinoline was most toxic to net production over the longer time scale. TEG exhibited the least toxicity to net production, however, TEG exhibited higher toxicity to heterotrophic activity than either quinoline or phenol.
Although the type of sediment used in the nicrocosms did not change the relative toxicities of the chemicals, the microcosms with clay sediment always were observed to exhibit lower net production and higher variability.
Nonparametric statistical analyses are recommended for microcosm studies because of the lack of normally distributed data. Confidence limits of 80% are recommended because of the need for biologically conservative estimates of ecosystem toxicity.Ph. D.
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Pokhrel, Lok R., Thilini Silva, Brajesh Dubey, Badawy Amro M. El, Thabet M. Tolaymat, and Phillip R. Scheuerman. "Rapid Screening of Aquatic Toxicity of Several Metal-Based Nanoparticles Using the Metplate™ Bioassay." Digital Commons @ East Tennessee State University, 2012. https://dc.etsu.edu/etsu-works/2873.
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Current understanding of potential toxicity of engineered nanomaterials to aquatic microorganisms is limited for risk assessment and management. Here we evaluate if the MetPLATE™ test can be used as an effective and rapid screening tool to test for potential aquatic toxicity of various metal-based nanoparticles (NPs). The MetPLATE bioassay is a heavy metal sensitive test based on β-galactosidase activity in Escherichia coli. Five different types of metal-based NPs were screened for toxicity: (1) citrate coated nAg (Citrate-nanosilver), (2) polyvinylpyrrolidone coated nAg (PVP-nAg), (3) uncoated nZnO, (4) uncoated nTiO2 and (5) 1-Octadecylamine coated CdSe Quantum Dots (CdSe QDs); and compared with their corresponding ionic salt toxicity. Citrate-nAg was further fractionated into clean Citrate-nAg, unclean Citrate-nAg and permeate using a tangential flow filtration (TFF) system to eliminate residual ions and impurities from the stock Citrate-nAg suspension and also to differentiate between ionic- versus nano-specific toxicity. Our results showed that nAg, nZnO and CdSe QDs were less toxic than their corresponding ionic salts tested, while nano- or ionic form of TiO2 was not toxic as high as 2.5 g L− 1 to the MetPLATE™ bacteria. Although coating-dependent toxicity was noticeable between two types of Ag NPs evaluated, particle size and surface charge were not adequate to explain the observed toxicity; hence, the toxicity appeared to be material-specific. Overall, the toxicity followed the trend: CdCl2 > AgNO3 > PVP-nAg > unclean Citrate-nAg > clean Citrate-nAg > ZnSO4 > nZnO > CdSe QDs > nTiO2/TiO2. These results indicate that an evaluation of β-galactosidase inhibition in MetPLATE™ E. coli can be an important consideration for rapid screening of metal-based NP toxicity, and should facilitate ecological risk assessment of these emerging contaminants.
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Snyder, Craig David. "Physiological, population, and genetic responses of an aquatic insect (Isonychia bicolor) to chronic mercury pollution." Diss., This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-06062008-165554/.
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Maharjan, Renu. "Phytoremediation of Selected Pharmaceuticals by and their Phytotoxicity to Aquatic Plants." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1396172003.
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Weaver, Meghan C. "Effects of Copper Sulfate Application on Zooplankton and Macroinvertebrate Communities in Upground Reservoirs." Bowling Green State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1339094079.
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Hum, Stanley. "Detection of latent heritable genetic damage in populations of aquatic snails, Lymnaea stagnalis, exposed in situ to genotoxic pollution." Thesis, McGill University, 1999. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=30670.
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We hypothesized that populations exposed to chronic levels of genotoxins for many generations in situ will accumulate latent heritable genetic damage leading to increases in mutational load and decreased population fitness. Common pulmonate snails (Lymnaea stagnalis) were collected from three sites that differed in pollution level [Manitoulin Island (reference), Beauharnois (moderate pollution), and Varennes (highly polluted)]. These organisms have a rapid generation time and are capable of self-fertilization. Fitness indicators were clutch size, survival (hatching to day 30) and growth (length from hatching to day 90). Recessive deleterious mutations that have accumulated through time are masked as snails preferentially outcrossed, but are expressed when snails self-fertilize. Results obtained by comparing fitness components of snails derived from selfing and outcrossing experiments showed that in sites with higher levels of pollution inbreeding depression increased for clutch size and survival. Results for growth rate were similar to those for clutch size and survival in the two least polluted sites, but not for the most polluted site, due possibly to biased mortality of smaller snails at this site. After correction for size biased mortality, the growth estimates showed patterns similar for the two polluted sites when compared to the reference site. This study suggests that long-term in situ exposure to genotoxic pollution may effect population fitness due to the accumulation of latent heritable genetic damage.
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Waye, Andrew. "An Investigation of Pulp Mill Effluents and Their Wood Feedstocks as Potential Neuroendocrine Disruptors of the Fish Reproductive Axis." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32145.
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Common observations of reduced gonad size and spawning inhibition in wild and laboratory raised fish exposed to pulp mill effluents indicate that reproductive neuroendocrine signalling pathways may be upset. This thesis supported the neuroendocrine disruption of reproduction hypothesis by identifying potential disruptors and targets where these impacts may occur. A mechanistic study of the in vivo fathead minnow (FHM) spawning assay used by industry to assess effluent quality showed that ovulation, but not milt production, was impaired. This finding supported the hypothesis that the neuroendocrine cascade that triggers ovulation may be disrupted. I hypothesized that neuroactive constituents previously described in effluents were originating in wood feedstocks and neuroactive extracts of hardwood and conifer feedstocks were identified. Phytochemicals associated with effluents were neuroactive. Structurally similar phenolic phytochemicals showed monoamine oxidase (MAO) inhibition, and resin acid diterpenes displayed glutamic acid decarboxylase (GAD) inhibition. Inhibitors of these enzymes may have impacts on the control of reproduction since MAO metabolizes dopamine, an inhibitor of the neuroendocrine reproductive axis, while GAD synthesizes -aminobutyric acid (GABA), a stimulator of this axis. Bioassay-guided fractionations of effluents and wood feedstocks identified that medium polar extracts of primary- and secondary-treated effluents and balsam fir feedstock contained high GAD inhibitory activity. This activity was associated with chemically complex fractions rather than single active principles. Advanced metabolomic comparison of medium polar extracts of feedstock and treated effluent identified 15 common plant metabolites, demonstrating that phytochemicals entering the mill in wood are surviving pulp production and effluent treatment processes and may be responsible for observed GAD inhibition. Discriminant metabolomics analysis identified 4-acetylpyridine, a novel compound to be described in effluents, as well as two other tentatively identified compounds, as chemical markers of GAD inhibitory effluent fractions. Five tentatively identified chemical markers and (+)-lariciresinol were found in inhibitory balsam fir feedstock fractions. Neuroendocrine pathways that control reproduction in fish, such as dopamine and GABA pathways, are also important drug targets for the treatment of neurological disorders in mammals; therefore these results also have implications for the development of natural health products from phytochemicals and tree extracts common to Canadian forests. By using an interdisciplinary approach (phytochemistry, neuroendocrinology, ecotoxicology), I was able to explore the various implications of my research on the fields of natural health products chemistry and aquatic toxicology.
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De, Almeida Louise Kashiyavala Sophia. "The detection of glyphosate and glyphosate-based herbicides in water, using nanotechnology." Thesis, Rhodes University, 2015. http://hdl.handle.net/10962/d1019755.
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Glyphosate (N-phosphonomethylglycine) is an organophosphate compound which was developed by the Monsanto Company in 1971 and is the active ingredient found in several herbicide formulations. The use of glyphosate-based herbicides in South Africa for the control of alien invasive plants and weeds is well established, extensive and currently unregulated, which vastly increases the likelihood of glyphosate contamination in environmental water systems. Although the use of glyphosate-based herbicides is required for economic enhancement in industries such as agriculture, the presence of this compound in natural water systems presents a potential risk to human health. Glyphosate and glyphosate formulations were previously considered safe, however their toxicity has become a major focal point of research over recent years. The lack of monitoring protocols for pesticides in South Africa is primarily due to limited financial capacity and the lack of analytical techniques.
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Smith, David P. (David Paul) 1956. "Responses of Pristina leidyi Smith 1896 (Naididae: Oligochaeta) to Cadmium, Vanadium, and Some Environmental Factors." Thesis, University of North Texas, 1990. https://digital.library.unt.edu/ark:/67531/metadc500695/.
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Concern over sediment toxicity has increased the need for toxicity test information with organisms that inhabit sediments. Oligochaetes are exposed to toxicants through feeding and direct body contact with aquatic sediments. Chronic testing with oligochaetes has historically focused on tubificids with test lengths of one year or more to encompass several generations. Most naidid oligochaetes have generation times of three to seven days and could provide chronic information in a matter of weeks. The cosmopolitan distributed naidid, Pristina leidyi, was evaluated for use as a toxicity test organism. Results of research conducted includes culture methods, effects of temperature on reproduction, growth rates in a reference sediment, acute toxicity tests, and chronic toxicity tests.
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Dixon, William J., and bill dixon@dse vic gov au. "Uncertainty in Aquatic Toxicological Exposure-Effect Models: the Toxicity of 2,4-Dichlorophenoxyacetic Acid and 4-Chlorophenol to Daphnia carinata." RMIT University. Biotechnology and Environmental Biology, 2005. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20070119.163720.
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Uncertainty is pervasive in risk assessment. In ecotoxicological risk assessments, it arises from such sources as a lack of data, the simplification and abstraction of complex situations, and ambiguities in assessment endpoints (Burgman 2005; Suter 1993). When evaluating and managing risks, uncertainty needs to be explicitly considered in order to avoid erroneous decisions and to be able to make statements about the confidence that we can place in risk estimates. Although informative, previous approaches to dealing with uncertainty in ecotoxicological modelling have been found to be limited, inconsistent and often based on assumptions that may be false (Ferson & Ginzburg 1996; Suter 1998; Suter et al. 2002; van der Hoeven 2004; van Straalen 2002a; Verdonck et al. 2003a). In this thesis a Generalised Linear Modelling approach is proposed as an alternative, congruous framework for the analysis and prediction of a wide range of ecotoxicological effects. This approach was used to investigate the results of toxicity experiments on the effect of 2,4-Dichlorophenoxyacetic Acid (2,4-D) formulations and 4-Chlorophenol (4-CP, an associated breakdown product) on Daphnia carinata. Differences between frequentist Maximum Likelihood (ML) and Bayesian Markov-Chain Monte-Carlo (MCMC) approaches to statistical reasoning and model estimation were also investigated. These approaches are inferentially disparate and place different emphasis on aleatory and epistemic uncertainty (O'Hagan 2004). Bayesian MCMC and Probability Bounds Analysis methods for propagating uncertainty in risk models are also compared for the first time. For simple models, Bayesian and frequentist approaches to Generalised Linear Model (GLM) estimation were found to produce very similar results when non-informative prior distributions were used for the Bayesian models. Potency estimates and regression parameters were found to be similar for identical models, signifying that Bayesian MCMC techniques are at least a suitable and objective replacement for frequentist ML for the analysis of exposureresponse data. Applications of these techniques demonstrated that Amicide formulations of 2,4-D are more toxic to Daphnia than their unformulated, Technical Acid parent. Different results were obtained from Bayesian MCMC and ML methods when more complex models and data structures were considered. In the analysis of 4-CP toxicity, the treatment of 2 different factors as fixed or random in standard and Mixed-Effect models was found to affect variance estimates to the degree that different conclusions would be drawn from the same model, fit to the same data. Associated discrepancies in the treatment of overdispersion between ML and Bayesian MCMC analyses were also found to affect results. Bayesian MCMC techniques were found to be superior to the ML ones employed for the analysis of complex models because they enabled the correct formulation of hierarchical (nested) datastructures within a binomial logistic GLM. Application of these techniques to the analysis of results from 4-CP toxicity testing on two strains of Daphnia carinata found that between-experiment variability was greater than that within-experiments or between-strains. Perhaps surprisingly, this indicated that long-term laboratory culture had not significantly affected the sensitivity of one strain when compared to cultures of another strain that had recently been established from field populations. The results from this analysis highlighted the need for repetition of experiments, proper model formulation in complex analyses and careful consideration of the effects of pooling data on characterising variability and uncertainty. The GLM framework was used to develop three dimensional surface models of the effects of different length pulse exposures, and subsequent delayed toxicity, of 4-CP on Daphnia. These models described the relationship between exposure duration and intensity (concentration) on toxicity, and were constructed for both pulse and delayed effects. Statistical analysis of these models found that significant delayed effects occurred following the full range of pulse exposure durations, and that both exposure duration and intensity interacted significantly and concurrently with the delayed effect. These results indicated that failure to consider delayed toxicity could lead to significant underestimation of the effects of pulse exposure, and therefore increase uncertainty in risk assessments. A number of new approaches to modelling ecotoxicological risk and to propagating uncertainty were also developed and applied in this thesis. In the first of these, a method for describing and propagating uncertainty in conventional Species Sensitivity Distribution (SSD) models was described. This utilised Probability Bounds Analysis to construct a nonparametric 'probability box' on an SSD based on EC05 estimates and their confidence intervals. Predictions from this uncertain SSD and the confidence interval extrapolation methods described by Aldenberg and colleagues (2000; 2002a) were compared. It was found that the extrapolation techniques underestimated the width of uncertainty (confidence) intervals by 63% and the upper bound by 65%, when compared to the Probability Bounds (P3 Bounds) approach, which was based on actual confidence estimates derived from the original data. An alternative approach to formulating ecotoxicological risk modelling was also proposed and was based on a Binomial GLM. In this formulation, the model is first fit to the available data in order to derive mean and uncertainty estimates for the parameters. This 'uncertain' GLM model is then used to predict the risk of effect from possible or observed exposure distributions. This risk is described as a whole distribution, with a central tendency and uncertainty bounds derived from the original data and the exposure distribution (if this is also 'uncertain'). Bayesian and P-Bounds approaches to propagating uncertainty in this model were compared using an example of the risk of exposure to a hypothetical (uncertain) distribution of 4-CP for the two Daphnia strains studied. This comparison found that the Bayesian and P-Bounds approaches produced very similar mean and uncertainty estimates, with the P-bounds intervals always being wider than the Bayesian ones. This difference is due to the different methods for dealing with dependencies between model parameters by the two approaches, and is confirmation that the P-bounds approach is better suited to situations where data and knowledge are scarce. The advantages of the Bayesian risk assessment and uncertainty propagation method developed are that it allows calculation of the likelihood of any effect occurring, not just the (probability)bounds, and that the same software (WinBugs) and model construction may be used to fit regression models and predict risks simultaneously. The GLM risk modelling approaches developed here are able to explain a wide range of response shapes (including hormesis) and underlying (non-normal) distributions, and do not involve expression of the exposure-response as a probability distribution, hence solving a number of problems found with previous formulations of ecotoxicological risk. The approaches developed can also be easily extended to describe communities, include modifying factors, mixed-effects, population growth, carrying capacity and a range of other variables of interest in ecotoxicological risk assessments. While the lack of data on the toxicological effects of chemicals is the most significant source of uncertainty in ecotoxicological risk assessments today, methods such as those described here can assist by quantifying that uncertainty so that it can be communicated to stakeholders and decision makers. As new information becomes available, these techniques can be used to develop more complex models that will help to bridge the gap between the bioassay and the ecosystem.
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Albertus, Randal Marius Colin. "Ecotoxicity and environmental fate of diesel and diesel blends produced by Sasol’s Fischer-Tropsch processes using natural gas and coal as feedstock as well as biodiesel and biodiesel blends." Thesis, Stellenbosch : Stellenbosch University, 2012. http://hdl.handle.net/10019.1/71807.
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Thesis (PhD)--Stellenbosch University, 2012.ENGLISH ABSTRACT: World crude oil demand and production is set to increase in the long term and is projected to increase from 82 barrels per day in 2007 to an estimated 104 million barrels per day in 2030 according to the International Energy Agency. The environmental challenges posed by the current and projected increased future fuel use, with specific reference to air, aquatic and terrestrial impact, are driving producers and legislators to change fuel specifications and consequently fuel properties to be less harmful to the environment. Traditionally transportation fuels are produced through crude oil refining but in South Africa more than one third of the liquid fuels are produced synthetically through catalytic conversion of gassified coal via the Fischer-Tropsch process by Sasol. Diesel from syncrude is referred to as synthetic diesel and the refiner must blend various hydrocarbon streams, effectively tailoring the diesel to its final composition. Biodiesel from renewable sources like vegetable oils is considered environmentally more acceptable than petrodiesel because of its high biodegradability in the environment, lower sulphur and aromatic hydrocarbon content as well as lowered particulate content in the exhaust emissions. The present research was aimed at evaluating whether the composition of diesels derived from different feed stocks, that included coal, natural gas, crude oil and soybean oil, would influence its biodegradability and ecotoxicity. Acute aquatic tests that included freshwater fish, crustaceans, algae and marine bacteria were used to determine the acute toxicity of diesels. In addition, quantitative structure activity relationship models were used to estimate the biodegradation and ecotoxicity properties of the diesels in an attempt to develop a cost effective tool to determine those properties. The results indicated that the 2-D GC technique quantitatively and qualitatively identified the hydrocarbon constituents in the diesels. The relevance of using the 2-D GC technique was in identifying and quantifying the hydrocarbon breakdown products and being used in a mass balance to confirm the potential biological breakdown processes of the materials used in the present study. The differences in theoretical oxygen demand (ThOD) of the different experimental diesel blends using various blending materials and biodiesel, emphasised and confirmed the importance of calculating the ThOD for the respective blending materials when measuring the biodegradation rates. Furthermore, the biodegradation hierarchy of Pitter and Chudoba (1990) in order of decreasing biodegradability: alkanes > branched alkanes > cyclo-alkanes > aromatic hydrocarbons, could be expanded to include FAME: FAME > alkanes > branched alkanes > cyclo-alkanes > aromatic hydrocarbons. The biochemical pathways identified for the biodegradation of all the diesels was enzyme-enhanced β-oxidation. The present research also indicated that biodiesel addition to crude-derived diesels to increase the density to within the current required specifications for diesels cannot be a reality in SA because of the underdeveloped biodiesel industry. To increase the density by using biodiesel to within the specification for GTL diesel, more than 27% biodiesel would be required, which is currently is not achievable from an economic perspective as well as governmental national strategy perspective. The addition of biodiesel as lubricity enhancer seems more plausible, because less than 5% would be required for petrodiesels. The results on the ecotoxicity of the diesels and diesel blends demonstrated a general lack of acute toxic effect, especially for the fish and crustaceans used during the present study. Although algal and bacterial tests showed an effect at most of the WAF loading rates, none were high enough to enable the calculation of a median effect loading rate (EL50). QSAR‟s, like EPI Suite, together with prediction models, like the Fisk Ecotoxicity Estimation Model, can be used to screen for ecotoxicity and biodegradability of hydrocarbons found in Petrodiesels. It was less applicable for the prediction of biodiesel constituents. The use of different cut-off values for the constituents of biodiesel could be developed in future research. The use of this combination enabled the present research into the potential toxicity of hydrocarbon mixtures to be conducted, especially since tests on individual constituents are impractical. QSAR‟s may provide a relatively cost-effective way to screen for potential environmental acceptability of such mixtures. The contributors to the toxicity of mixtures of hydrocarbons found in diesels were evaluated and it appears that paraffins contribute more to the overall toxicity than previously thought and aromatics less. By putting well-defined policies and incentives in place, a robust biodiesel industry could be created that will enable SA to contribute to the mitigation of the threat of climate change, to become less dependent on foreign oil and to develop rural agriculture. The key to energy security is not one solution to South Africa‟s energy needs, but a multifaceted approach to the complex subject of sustainable energy security. The end of the hydrocarbon era of energy is not in sight, at least for the near future, but soon even hydrocarbon energy in the form of coal and crude oil will have to be re-evaluated as SA‟s major energy resource for economic and energy security. In SA the potential of developing natural gas resources through fracking, nuclear, solar, wind, biological and even wastes to energy processes as well as better energy efficiency, in a balanced and diverse energy portfolio, could pave the way toward energy security in the long run.
AFRIKAANSE OPSOMMING: Ru-olie aanvraag en produksie wêreldwyd is besig om toe te neem en die Internasionale Energie Agentskap projekteer dat wêreld ru-olie verbruik sal toeneem van 82 vate per dag in 2007 tot „n beraamde 104 vate per dag in 2030. Die omgewings uitdagings wat huidige en toekomstige toename in brandstof verbruik, spesifiek die impak op lug gehalte, water- en grond, mag hê, is dryfvere vir produseerders en reguleerders om brandstof spesifikasies te verander om minder omgewings impak te veroorsaak. Brandstof vir vervoer doeleindes word oor die algemeen van ru-olie gemaak, maar in Suid Afrika word ongeveer „n derde van die vloeibare brandtof gemaak deur middel van gekatiliseerde omskakeling van vergasde steenkool via die Fischer-Tropsch proses by Sasol. Diesel wat uit sintetiese ru-olie gemaak is, is sinteties en die raffineerder moet verskillende koolwaterstof strome meng om „n finale produk te lewer. Biodiesel wat uit hernubare hulpbronne soos plant-olies en diervet gemaak word, kan oorweeg word vir die vervaardiging van meer omgewings aanvaarbare brandstof met laer swael en aromatiese koolwaterstof inhoud en ook minder partikel inhoud in die uitlaatgas. Die huidige navorsing het beoog om te evalueer of die samestelling van diesels wat vervaardig is uit verskillende hulpbronne, wat steenkool, aardgas, ru-olie en sojaboon olie ingesluit het, die biodegradeerbaarheid en ekotoksisiteit kan beïnvloed. Akute akwatiese toetse wat varswater vis, krustaseë, alge en marine bakterieë ingesluit het, was aangewend om die akute toksisiteit van die diesels te bepaal. Kwantitatiewe struktuur aktiwiteit verwantskaps modelle is ook gebruik om die biodegradeerbaarheid en ekotoksisiteits eienskappe van die diesels te beraam om vas te stel of 'n bekostigbare alternatief beskikbaar is om daardie eienskappe te bepaal. Die resultate het aangedui dat die 2D GC tegniek kwantitatief en kwalitatief gebruik kan word om die koolwaterstowwe in die diesels te identifiseer. Die benutting van die 2D GC tegnieke is egter om die koolwaterstof afbraak produkte te identifiseer en ook om die massa balans gedurende die biodegradering te bevestig. Die verskil in teoretiese suurstof aanvraag van die verskillende diesels het die belangrikheid daarvan blemtoon en bevestig om die teoretiese suurstof aanvraag korrek te bereken en sodoende die biodegradasie korrek te bepaal. Verder kan die biodegradasie hierargie van Pitter en Chudoba (1990) volgens afnemende biodegradasie: alkane > vertakte alkane > siklo-alkane > aromatiese koolwaterstowwe, uitgebrei word om vetsuur-metielesters in te sluit: vetsuur-metielesters > alkane > vertakte alkane > siklo-alkane > aromatiese koolwaterstowwe. Die biochemiese roetes wat geïdentifiseer is vir die biodegradasie van die diesels, was ensiem-verbeterde β-oksidasie. Die huidige navorsing het ook aangedui dat biodiesel toevoeging tot ru-olie vervaardigde diesel om die digtheid te verhoog to binne huidige spesifikasies is nog nie lewensvatbaar in Suid Afrika nie as gevolg van die onderontwikkelde biodiesel industrie. Om die digtheid te verhoog met biodiesel tot binne spesifikasie verg meer as 27% biodiesel en is huidiglik nie haalbaar vanuit 'n ekonomiese persketief en ook nie vanuit 'n regerings nasionale strategie perspektief nie. Die toevoeging van biodiesel as lubrisiteits vervetering blyk meer van toepassing te wees aangesien minder as 5% biodiesel toevoeging benodig sou wees. Die resultate van die ekotoksisiteits toetse het 'n algemene gebrek aan akute toksisiteits effek aangedui, veral vir vis en skaaldiere wat in die huidige studie gebruik is. Howel alge en bakteriële toetse daarop gedui het dat 'n toksiese effek wel aanwesig was, was dit gering en kon die median effektiewe ladings koers (EL50) nie bepaal word nie. QSARs, soos Epi Suite, tesame met voospellings modelle, soos die Fisk Ecotoxicity Estimation Model, kan gebruik word om ekotoksisiteit en biodegradeerbaarheid van koolwaterstowwe in petrodiesels te beraam, alhoewel dit minder van toepassing was op biodiesel. Die gebruik van ander afsny waardes spesifiek vir biodiesel kan oorweeg word in toekomstige navorsing. Die molecules wat bygedra het tot die toksisiteit van die koolwaterstof mengsels was geëvalueeren daar is gevind dat die paraffiniese molekules meer begedra het tot die totale toksisiteit en die aromate minder. Deur goed gedefinieerde beleid en aansporings meganismes inplek te sit, kan 'n biodiesel industrie in SA geskep word wat SA sal help om by te dra tot die bekamping van klimaats vendering en sodoende minder afhanklik te wees van buitelandse olie en ook landbou in SA te bevorder. Die sluetel tot energie sekuriteit is nie een oplossing vir SA se energie aanvraag nie, maar eerder 'n veelsydige benadering tot die komplekse onderwerp van volhoubare energie sekuriteit. Die einde van koolwaterstof energie is nog nie in sig nie, ten miste nie in die nabye toekoms nie, maar binnekort sal selfs koolwaterstof energie in die vorm van steenkool en ru-olie heroorweeg moet word as SA se hoof energie hulpbronne vir ekonomiese en energie sekuriteit. In SA moet die potensiaal van natuurlike gas ontginning deur middel van hidrauliese breking, kernkrag, wind energie, biologiese energie en selfs afval tot energie prosesse bestudeer word, so-ook beter energie doeltreffendheid om sodoende 'n gebalansweerde energie portefuelje te skep wat die weg sal baan na energie sekuriteit op die lang termyn.
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Castro, Català Núria de. "Invertebrate community responses to pollutants in mediterranean basins : insights from ecotoxicological approaches = Respostes de la comunitat d'invertebrats als contaminants en conques mediterrànies: aproximacions ecotoxicològiques." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/386400.
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Aquatic systems are under pressure from multiple stressors that affect the structure, the functioning, and the health of species, communities and ecosystems. One of the main human pressures affecting the Earth’s ecosystems is chemical pollution. Large-scale chemical production has led to the release of these compounds from agricultural, industrial, and municipal waste, into riverine, transitional, and marine waters. These pollutants can cause harmful effects on aquatic species and communities, in turn causing severe negative impacts on the structure and functioning of ecosystems, and the goods and services they provide. Chemical pollution is not only one of the most important threats to aquatic systems, it is also a complex threat due to the diversity of compounds present in these systems and the dynamics and interaction of these compounds with physical (water, sediment) and biological (amphibian, fish, invertebrate, algae) compartments. Furthermore, aquatic pollution is of special concern in Mediterranean basins, which suffer high flow variability and receive significant contaminant inputs from diffuse and point sources. Future scenarios predict that these basins will be increasingly affected by both the scarcity of water, enhanced by climate change, and high pollution.
Apart from well-known pollutants, called priority substances, many studies have revealed the widespread occurrence of low level concentrations of organic micropollutants, also known as emerging contaminants (ECs), and awareness is growing with regard to the importance of mixtures of several contaminants, priority and emerging, as found in the more polluted water bodies of Europe. Different tools can be used in order to link the chemical and ecological quality of aquatic ecosystems: ecological methods (Chapter 3, 4 and 5), biomarkers of field-exposed organisms (Chapter 4 and 6), or in vitro and in vivo bioassays (Chapter 4, 5, 6 and 7). By combining these different tools, this thesis provides evidence of the effects of chemical stressors (emerging and priority pollutants) on invertebrate communities in four threatened Mediterranean rivers of the Iberian Peninsula: the Ebro, the Llobregat, the Júcar and the Guadalquivir. The ecotoxicological effects have been detected at community level, but also at the population and individual levels. It has been found that contaminants in water and also contaminants accumulated in surficial sediments affect community structure (richness and abundance). It has also been seen these contaminants affect the reproductive capacity (number of eggs), the development, the feeding, growth and the activity of antioxidative enzymes (catalase) of diferent species. The general picture obtained shows that priority and emerging pollutants represent a serious toxicity risk for invertebrates in these basins, and that the main specific drivers of this risk are pesticides, alkylphenols, and metals. Additionally, the thesis is completed with a laboratory experiment where the direct and indirect effects of two specific contaminants in the detritivorous Gammarus pulex have been tested. Research based on field studies and laboratory toxicity tests, combining experimental assays with natural community studies, is essential to understand the effects of stressors at different scales and to prevent future degradation of aquatic ecosystems. This thesis integrates observational and experimental approaches of diferent environmental disciplines (environmental chemistry, ecotoxicology and ecology) to elucidate the effects of pollution. The combination of experimental tests to study natural communities can help to understand the effects of disturbances at different scales and prevent the degradation of aquatic ecosystems and improve its management.Els sistemes aquàtics estan subjectes a la pressió de múltiples pertorbacions que afecten l'estructura i el funcionament de les comunitats i ecosistemes. Una de les principals pressions antropogèniques que afecten als ecosistemes aquàtics és la contaminació. La producció química a gran escala ha donat lloc a l'alliberament de substàncies d’origen agrícola, industrial i urbà als sistemes fluvials. Aquesta contaminació és una amenaça complexa i múltiple, degut a la diversitat de compostos presents i a la dinàmica i interacció d'aquests amb els compartiments físics (aigua, sediments) i biològics (organismes). A les conques fluvials mediterrànies, on la variabilitat hidrològica és important, aquesta contaminació és motiu d'especial preocupació especialment en el període d’estiatge, quan disminueix la capacitat de dilució dels rius. A més dels contaminants prioritaris legislats, molts estudis han posat de manifest la presència generalitzada de microcontaminants, també anomenats contaminants emergents. Aquesta tesi proporciona evidència dels efectes dels contaminants emergents i prioritaris en les comunitats d'invertebrats en quatre conques mediterrànies de la Península Ibèrica: l'Ebre, el Llobregat, el Xúquer i el Guadalquivir, emprant mètodes ecològics, biomarcadors, i bioassaigs in vitro i in vivo. Els efectes ecotoxicològics s’han detectat a nivell de comunitat, de població i d’individu, i s’ha vist que tant els contaminants presents a l’aigua com els acumulats en els sediments superficials afecten l’estructura de la comunitat (riquesa específica i abundàncies). També s’ha vist que la contaminació afecta la capacitat de reproducció (nombre d’ous), el desenvolupament, l’alimentació, el creixement i l’activitat d’enzims antioxidatius (catalasa). En concret, els principals responsables de l’alt risc ecotoxicològic identificats han estat els plaguicides, els alquilfenols industrials, i els metalls. Addicionalment, la tesi es completa amb un experiment de laboratori on es testen els efectes directes i indirectes de dos contaminants concrets en el detritívor Gammarus pulex. Aquesta tesi integra aproximacions observacionals i experimentals de múltiples disciplines ambientals (química ambiental, ecotoxicologia i ecologia) per dilucidar els efectes dels diferents contaminants. La combinació dels assajos experimentals amb estudis de les comunitats naturals permet comprendre millor els efectes de les pertorbacions a diferents escales i prevenir la degradació dels ecosistemes aquàtics, així com millorar la seva gestió.
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Ludington, Timothy Shane Ludington. "The degree of impairment of foraging in crayfish (Orconectes virilis) due to insecticide exposure is dependent upon turbulence dispersion." Bowling Green State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1466173210.
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Whalen, John. "A Multibiomarker Analysis of Pollutant Effects on Atlantic Stingray Populations in Florida’s St. Johns River." UNF Digital Commons, 2017. http://digitalcommons.unf.edu/etd/725.
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The goal of this study was to examine the potential health effects of organochlorine (OC) and polycyclic aromatic hydrocarbon (PAH) exposure on Atlantic stingray populations in Florida’s St. Johns River (SJR). Special emphasis was placed on identifying OC- and/or PAH-related effects in stingrays from areas of the lower (LSJR) and middle (MSJR) basins shown to possess elevated levels of these compounds, as well as characterizing baseline levels of pollutant exposure in the SJR shipping channel, which may be subjected to dredging in the near future, potentially resuspending and redistributing contaminated sediments and increasing pollutant-associated effects. To accomplish this, we measured OC and PAH biomarker levels in stingrays collected from contaminated and reference sites. We specifically examined the phase I detoxification enzyme, cytochrome P4501a1 (CYP1a1); the phase II detoxification enzymes, glutathione-S-transferase (GST) and uridine 5’-diphosphate glucuronosyltransferase (UGT); fluorescent aromatic compounds, PAH bile metabolites; and lipid peroxidation (LPO), cell membrane damage. Biomarker values collected between 2014 and 2016 were compared by site. Detoxification enzyme activity and LPO values from individuals collected from the three MSJR lakes between 2002 and 2005 were compared to those collected between 2014 and 2016. The data suggested that biomarker values from the SJR were variable, with elevated levels from Lake Jesup. Compared to reference estuaries, the LSJR has low biomarker values. This indicates that residing in certain portions of the MSJR is detrimental to stingray health, while residing in the LSJR is not. Lake Monroe and Lake George biomarker levels indicated reduced contaminant input over time, whereas Lake Jesup biomarker levels suggested the opposite. This study has developed a baseline for biomarker levels in the LSJR, allowing for the identification of dredging-induced changes to the system, and has identified temporal changes in biomarker levels from three MSJR lakes.