<p> This study analyzed fossil and modern freshwater bivalve mollusc shells, from in and around lakes Ontario and Erie, for the following trace metals: Cu, Ni, Zn, As, Pb, and Mn. Elliptio dilatata, Elliptio complanata, and Lampsilis radiata siliquoidea shells were analyzed by ICPMS for differences in shell metal levels between species and genera, through time and due to anthropogenic inputs. </p> <p> Regardless of age, all three species showed high concentrations of Zn and Mn, and little or no changes in Cu, Ni, Zn, and Pb concentrations with time. E. comp1anata shells were generally poorer in Pb, but richer in As and Mn, than were the E. dilatata and L. radiata siliquoidea shells. Fossil Elliptio samples did not posses low background, or baseline, trace metal concentrations. These samples were richer in As, Pb, and Mn than were modern samples from post-industrial environments. Among the modern shells, the E. complanata showed no differences in metal concentrations between samples from high- and low-contamination· sites, while the L. radiata siliquoidea showed changes in Ni, As, and Mn concentrations among the same sites. Modern L. radiata siliquoidea may be more likely to represent environmental metal changes than are modern E. complanata. Historical change in environmental metal concentrations of the Great Lakes region is not recorded as a simple change in shell metal concentrations of these freshwater bivalve molluscs. </p> / Thesis / Bachelor of Science (BSc)

The Great Lakes Fish Eaters Project (Eaters Project) was funded by Health Canada to identify individuals consuming large amounts of Great Lakes fish (≥ 26 meals over the past 1 year period) and to document relevant contaminant information to describe the potential health risks and benefits associated with the consumption of fish from the Great Lakes. Data were analyzed on 91 participants in the Eaters Project. The Great Lakes are home to a wide variety of fish. In this study alone, the participants have collectively eaten over 35 different species of Great Lakes fish. The participants of this study were asked for their opinions on the environment and their health. In addition, blood work was completed on 89 participants. The laboratory results were collected on different contaminants. Seven contaminants were considered for modeling purposes since the laboratory value was above a pre-defined detection limit in greater than 75% of the participants in this study. These seven contaminants included six Organochlorine Pesticides: p,p'-DDE (100% of the participants above the detection limit), hexachlorobenzene (HCB) (100%), β- hexachlorocyclohexane (β-HCH) (92.1%), mirex (78.7%), oxychlordane (92.1%), transnonachlor (98.9%) and one Polychlorinated Biphenyl Congener, Aroclor 1260 (100%). Organic mercury was also modeled since it contributed on average 77.2% to a maximum of 97.5% of the total mercury value. A 2-stage modeling approach on linear and categorical variables was done as a hypothesis building exercise. Each contaminant was age-adjusted at the start of this modeling exercise. The age-adjusted contaminant was then used as the response variable in the second stage of the modeling of each specific contaminant. The gender (male and female) and country of birth (Canada/Europe/US and Asian) variables were confounded with each other. The model was be stratified on country of birth or on gender if one of the variables were found to be the only significant variable left in the full model. Not all the contaminants that were modeled had significant results. That is, there were levels of certain contaminants that the modeling approach could not explain. The country of birth (Canada/Europe/US and Asian) variable was important in the modeling of some of the contaminants. This suggested stratifying by the two country-of-birth groups. / Thesis / Master of Science (MSc)

No description available.

Anthropogenic eutrophication of freshwater lakes due to land use change is a growing global problem with economic consequences, such as a reduction in shoreline property value. Managing eutrophication is of utmost importance in Maine, USA due to the large number of inland fresh waterbodies and their economic importance for fisheries, recreation, and real estate. This thesis investigates the relationships between water quality and catchment land use. Agricultural land use is a large driver of excess nutrient export to lakes, including in Maine, and can result in toxic cyanobacterial blooms, decreased water clarity, and fish kills. I developed a statistical relationship to quantitatively link agricultural intensity in the catchment and resultant water quality outcomes in Maine lakes. I observe a strong statistical relationship between water quality and anthropogenic activity in the catchment, as expected. Interestingly, I found that the effects of anthropogenic activity were most closely related to a five-year lag in water quality, which is between 0.8 to 4.71 years longer than the lake residence times. My results suggest that changes in land use may have long-term effects on water quality that last for far longer than would be expected. The analysis presented in this paper is novel for directly linking long term observational agricultural and biological datasets and presents a new way to quantitatively link water quality and anthropogenic intensity in the catchment area. / Master of Science

Lake Manassas is a man-made impoundment in the Northern Virginia suburbs of Washington, D.C. The lake currently supplies drinking water at an average rate of 10.5 million gallons per day to the City of Manassas, Virginia. The lake discharges, via the Broad Run, a tributary of the Occoquan Reservoir. The Occoquan Reservoir supplies potable water to over 750,000 people in the Northern Virginia area. This thesis presents the results of a limnological analysis of Lake Manassas. The techniques used are established limnological techniques to arrive at a profile which can be compared to accepted scales of ranking. One conclusion from the analysis is that Lake Manassas is eutrophic, which means that the production of biomass in the lake is at a higher than desired rate. The result of this eutrophic condition is that the water quality of the lake will decline rather rapidly. Another conclusion is that Broad Run is the major supplier of nutrients into Lake Manassas, but that conditions are also affected by a point source discharge from a sewage treatment plant. These conclusions are consistent with previous studies done on Lake Manassas. In summary, Lake Manassas is an important water resource in the Northern Virginia area, and it is important to continue to closely monitor and manage runoff practices in the watershed to ensure the lake does not degrade to unacceptable conditions. / Master of Science

The objective of this research was to examine whether the United States and Canada have successfully implemented their Great Lakes Water Quality Agreement and to identify the factors determining the continuation of any injury to human health from pollution of the boundary waters. The Agreement was first negotiated in 1972 as part of the legitimation of the social unrest of the 1960s and gave special responsibilities to the International Joint Commission to advise the Parties of problems of water quality. It has been subject to periodic review and occasional renegotiation and amendment. Specifically, the Agreement was renegotiated in 1978 to address the health effects from the imperceptible exposures to persistent toxic substances. Though extensive scientific evidence of continuing injury to health from persistent toxic substances has been available, there has been a consistent pattern of deliberate failure by the authorities to report the injury and to implement many of the remedial provisions contained in the Agreement. The thesis claims that the failure of the International Joint Commission to advise the Parties of the new information about the injury to health and the failure of the Parties to act upon the information when it was obtained from other sources constituted dereliction of duty. While synthesis of the science linking the pollutant-induced injury to specific causal agents was necessary to provide an empirical measure of the failure to implement the Agreement, consideration of the social, economic and political aspects was needed to provide a sufficient explanation for the failure of the International Joint Commission to inform and of the authorities to act. There have been active attempts to use diversionary reframing of the Agreement, based on a multi-causal ecosystem theory proposed by fisheries ecologists, to attenuate the risk message and transform the Great Lakes Water Quality Agreement into a more inclusive and less focused agreement on restoring ecosystem integrity. This has been welcomed by industry and governments as a means to remove the focus from addressing the unresolved dangers of persistent toxic substances through costly remedial actions. The International Joint Commission undermined its credibility when it recommended ‘sunsetting’ the use of chlorine in chemical manufacturing. The Parties failed to use a precautionary approach to prevent the commercial introduction of new persistent toxic substances, such as the brominated flame retardants. Since the 1980s, the economic politics of the two nations have been profoundly influenced by neo-liberalism and one of the consequences has been the removal of environmental health as a priority from the respective political agenda. Advisory bodies seem to have been captured not only by the prevailing neo-liberalism but also by corporate interests and these factors seem to underlie the reluctance to report the injury to health from exposures to persistent toxic substances. Though there were many different health endpoints affected by exposures to water pollutants in the Great Lakes, the thesis concentrated on the evidence of neuro-teratogenic effects. The adequacy of the implementation of the Agreement during the past thirty-three years was tested by using Health Canada data on cerebral palsy hospitalisation to evaluate whether there were indications of previously undetected outbreaks of congenital Minamata disease in human populations in Canadian Great Lakes communities potentially exposed to methyl mercury from natural sources or from historic industrial uses of mercury. The uncertainties in the apparent association that was found were reduced by the application of Hill’s guidelines. While these findings indicated both the need for further multi-disciplinary research to locate and diagnose the victims and for a precautionary approach to the consumption of Great Lakes fish, they also indicated that, for more than three decades, health authorities have not diligently implemented the Agreement. The inclusion of the social, economic and political considerations in the forensic audit has revealed the dangers inherent in any renegotiation of the Great Lakes Water Quality Agreement.

Thesis (M. Phil.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Uranium mining activities have the potential to impact aquatic systems through mine drainage (runoff) and the release of treated effluent into nearby watersheds. Such anthropogenic exposure can lead to elevated concentrations of metals and major ions, which may impact aquatic biota. Previous studies have looked at the effects of water quality on aquatic biota within flooded pit lakes and natural lakes that have been exposed to various mechanisms of mining exposure. However, the literature often only examines the effects of a limited number of contaminants on a limited number of species. Researchers have rarely looked at the effects of multiple contaminants on species composition, biodiversity and ecosystem function in aquatic systems. This study uses a multivariate approach to look for relationships between water quality (24 variables), plankton species composition and abundance, biodiversity (richness and evenness) and ecosystem function among lakes exposed to mining activities (n = 18) and non-exposed reference lakes (n = 8). Lake water quality data was used to cluster lakes into groups. Lake groups were then overlain onto multivariate ordinations derived from species composition-abundance data to determine if species composition was related to water quality. Ecosystem function variables included planktonic phosphorus cycling and planktonic respiration. The classified lake groups clustered well on ordinations derived from species composition-abundance data suggesting that relationships exist between water quality and plankton species composition. However, ecosystem function was similar among the majority of lakes and flooded pits despite differences in species richness, species composition and species abundance. Only a small number of aquatic systems had ecosystem function properties that were different from the majority of lakes and pits. These systems had the greatest concentrations of contaminants and had very low biodiversity (richness and evenness) compared to the other systems. Despite having differences in plankton species composition and species richness, all lake groups were functionally similar. This suggests that functional redundancy in species composition may be present in the majority of lakes and pits in such a way that ecosystem function is maintained.

Uranium mining activities have the potential to impact aquatic systems through mine drainage (runoff) and the release of treated effluent into nearby watersheds. Such anthropogenic exposure can lead to elevated concentrations of metals and major ions, which may impact aquatic biota. Previous studies have looked at the effects of water quality on aquatic biota within flooded pit lakes and natural lakes that have been exposed to various mechanisms of mining exposure. However, the literature often only examines the effects of a limited number of contaminants on a limited number of species. Researchers have rarely looked at the effects of multiple contaminants on species composition, biodiversity and ecosystem function in aquatic systems. This study uses a multivariate approach to look for relationships between water quality (24 variables), plankton species composition and abundance, biodiversity (richness and evenness) and ecosystem function among lakes exposed to mining activities (n = 18) and non-exposed reference lakes (n = 8). Lake water quality data was used to cluster lakes into groups. Lake groups were then overlain onto multivariate ordinations derived from species composition-abundance data to determine if species composition was related to water quality. Ecosystem function variables included planktonic phosphorus cycling and planktonic respiration. The classified lake groups clustered well on ordinations derived from species composition-abundance data suggesting that relationships exist between water quality and plankton species composition. However, ecosystem function was similar among the majority of lakes and flooded pits despite differences in species richness, species composition and species abundance. Only a small number of aquatic systems had ecosystem function properties that were different from the majority of lakes and pits. These systems had the greatest concentrations of contaminants and had very low biodiversity (richness and evenness) compared to the other systems. Despite having differences in plankton species composition and species richness, all lake groups were functionally similar. This suggests that functional redundancy in species composition may be present in the majority of lakes and pits in such a way that ecosystem function is maintained.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2017-05-26T15:02:40Z No. of bitstreams: 1 simonejaquelinecardoso.pdf: 1421959 bytes, checksum: 0bda7b55f248e227b23eb59614787c9a (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-05-26T15:14:55Z (GMT) No. of bitstreams: 1 simonejaquelinecardoso.pdf: 1421959 bytes, checksum: 0bda7b55f248e227b23eb59614787c9a (MD5) / Made available in DSpace on 2017-05-26T15:14:55Z (GMT). No. of bitstreams: 1 simonejaquelinecardoso.pdf: 1421959 bytes, checksum: 0bda7b55f248e227b23eb59614787c9a (MD5) Previous issue date: 2009-12-21 / A morfometria trata da quantificação e medida dos diversos elementos da forma, englobando, portanto, o conjunto de métodos para medir as dimensões físicas de um indivíduo ou sistema. As avaliações morfológicas têm sido um mecanismo de estudo de muitas áreas dentro da ciência e funcionam como ferramentas fundamentais tanto em escala microscópica, quanto em dimensões ecossistêmicas. Em sistemas lacustres, a compreensão dos fatores que envolvem variáveis morfométricas é de grande importância; pois, esses fatores, podem contribuir com muitas informações a respeito de suas estruturas e funções, sobre a dinâmica de cadeias tróficas, e a regulação do fluxo de substâncias desses ambientes. A morfologia dos sistemas lacustres é um fator importante também na distribuição de espécies em diferentes níveis de observação, sejam eles, locais, regionais ou globais. Resultados que suportam esta aplicabilidade foram encontrados neste estudo, que utilizou a comunidade fitoplanctônica como modelo de estudo. Foram realizados levantamentos morfométricos e de riqueza fitoplanctônica em 26 lagos amazônicos de águas claras e em 40 diferentes lagos naturais e artificiais, sendo 20 lagos brasileiros e 20 lagos de diferentes regiões do mundo. Através de regressões lineares simples, foram encontradas relações positivas significativas (p<0,005) entre a riqueza de espécies fitoplanctônicas e parâmetros morfométricos como área, perímetro, volume, índice de desenvolvimento de margem e índice de desenvolvimento de volume. No entanto, o índice de desenvolvimento de margem, foi o que me melhor representou a relação entre complexidade do sistema e a riqueza de espécies do fitoplâncton, caracterizando um efeito de borda em lagos. / Morphometry is the measurement of various elements of form, and it includes methods to measure since the physical dimensions of an individual to the dimensions of a system. Morphological evaluations are good study mechanisms in many areas of science and work as fundamental tools from a microscopic scale to the dimensions of an ecosystem. In lakes, the understanding of the factors involving morphometric variables is of great importance. These factors can contribute with a lot of information about the structures and functions, on the dynamics of food chains, and on regulating the flow of substances such systems. The morphology of lakes is also an important factor in the species distribution at different levels of observation, whether local, regional or global. Results supporting this applicability were found in this study, which used the phytoplankton community as a model. It was performed surveys on morphometric features and phytoplankton richness in 26 Amazonian clear water lakes and on 40 different natural and artificial lakes, 20 lakes in Brazil and 20 lakes in different regions of the world. Through linear regression, we found significant positive relationships (p<0.005) between phytoplankton richness and morphometric parameters such as area, perimeter, volume, shoreline development and volume development. Although, the shoreline development was the one that best correlated to the phytoplankton diversity, featuring such an edge effect in lakes.