Wastewaters from intensive agricultural activities contain high concentrations of nitrogen and phosphorus that contributes to water management problems. During the past few years, there has been considerable interest in the use of constructed wetlands for treating surface water runoff from farmyards. If the contaminated runoff is not treated, this wastewater along with other non-point sources of pollution can seriously contaminate the surface water and groundwater. Integrated Constructed Wetlands (ICWs) are a type of free water surface wetlands. They are engineered systems that are designed, constructed and operated successfully for treating farmyard runoff in the British Isles. However, the long-term treatment performance of these systems, the processes involved in contaminant removal and the impact on associated water bodies are not well-known. The aims of this project were to assess the performance of full-scale integrated constructed wetlands and understand nutrient removal in them. Performance evaluation of these systems through physical, chemical and microbiological parameters collected for more than 7 years showed good removal efficiencies compared to international literature. The monitored nutrient concentrations in groundwater and surface waters indicate that ICW systems did not pollute the receiving waters. The role of plants (Typha latifolia) and sediment in removing nutrients was also assessed. More nitrogen and phosphorus were stored in wetland soils and sediments than in plants. The results demonstrate that the soil component of a mature wetland system is an important and sustainable nutrient storage compartment. A novel molecular toolbox was used to characterise and compare microbial diversity responsible for nitrogen removal in sediment and litter components of ICW systems. Diverse populations of nitrogen removing bacteria were detected. The litter component of the wetland systems supported more diverse nitrogen removing bacteria than the sediments. Nitrogen removing bacteria in the wetland systems appeared to be stochastically assembled from the same source community. The self-organising map model was applied as a prediction tool for the performance of ICW and to investigate an alternative method of analysing water quality performance indicators. The model performed very well in predicting nutrients and biochemical oxygen demand with easy to measure and cost-effective water quality parameters. The results indicate that the model was an appropriate approach to monitor wastewater treatment processes and can be used to support management of ICW in real-time.

The aim of this thesis is to determine the sources, controls and risk aspects of fluoride in surface water and groundwater in a region of southeastern Sweden where the fluorine-rich 1.45 Ga circular Götemar granite (5 km in diameter) crops out in the surrounding 1.8 Ga granites and quartz monzodiorites (TIB rocks). The materials of this thesis include both primary data, collected for the purpose of this thesis, and a large set of secondary data, retrieved from the Swedish Nuclear Fuel and Waste Management Co., the Swedish Geological Survey and the Kalmar County Council. A characteristic feature of the area is high fluoride concentrations in all kinds of natural waters, including surface waters (such as streams) and groundwater in both the Quaternary deposits (regolith groundwater) and bedrock fractures (fracture groundwater). A number of potential sources and controls of the high fluoride concentrations were investigated, including a variety of geological, mineralogical, mineral-chemical and hydrological features and processes. For the stream waters and regolith groundwater, high fluoride concentrations were correlated with the location of the Götemar granite. This finding is explained by the discharge of fluoride-rich groundwater from fractures in the bedrock and/or the release of fluoride due to the weathering of fluorine-bearing minerals in the Quaternary deposits; however, the Quaternary deposits had considerably lower fluoride concentrations than the underlying bedrock. The high fluoride concentrations in the fresh fracture groundwater (up to 7.4 mg/L) in the TIB-rocks are proposed to be the result of long residence times and the alteration/dissolution of fluorine-bearing primary and secondary minerals along the fracture walls. In terms of risk aspects, this thesis shows that fluoride can add to the transport and inorganic complexation of aluminium in humic-rich, acidic streams. Additionally, 24 % of the children in households with private wells in Kalmar County were assessed to be at risk of excess fluoride intake based on the WHO drinking water guideline value (1.5 mg/L). However, the risk increased significantly when instead the US EPA reference dose (0.06 mg/kg-day) was used, both when all relevant exposure pathways were taken into account as well as water consumption alone. Hence, it is shown that the risk of an excess intake of fluoride is strongly dependent on the basis for evaluation.

La pollution des eaux de surface par les pesticides est un problème sérieux. Cette pollution étant en grande partie liée à l’activité agricole, la mise en place de pratiques permettant de limiter les transferts de pesticides vers les eaux de surface représente une solution intéressante. Afin d’apprécier l’efficacité de tels projets il est important de développer des méthodes spécifiques d’évaluation agri-environnementale. Si les méthodes d’évaluation parcellaires sont opérationnelles, celles à l’échelle du bassin versant ne sont pas encore bien adaptées aux besoins des acteurs de terrain. Ce travail a pour objectif de développer un indicateur de risque d’exposition des eaux de surface aux pertes de pesticides par ruissellement à l’échelle du bassin versant. Pour ce faire, nous avons développé deux indicateurs : un indicateur parcellaire évaluant l’impact des pratiques agricoles sur les pertes de pesticides par ruissellement en sortie de parcelle et un indicateur de connectivité estimant la contribution de chaque parcelle au ruissellement global du bassin versant. Le couplage de ces deux indicateurs permet d’obtenir un outil d’évaluation du risque des pratiques phytosanitaires spécifique d’un bassin versant et de comparer des scenarii. Les méthodes de développement des deux indicateurs se distinguent des méthodes classiques par leur fondement sur un couplage indicateur / modèle. L’hypothèse méthodologique principale sur laquelle repose ce travail est qu’à partir des processus décrits par les modèles, il est possible d’explorer une gamme de situations très large et de créer une base de connaissances qui permet de développer nos indicateurs / Surface water pollution by pesticides is a great environmental concern. In order to limit pesticides transfers from agricultural field to surface water, mitigation strategies are implemented. Their effectiveness has then to be assessed by specific tools. Most of pesticide runoff risk assessment tools are simple indicators or simulation models. Both can be performing for field application but most of the available methods are not yet adapted to help catchment managers in their decision process. Simple indicators lack taking into account inherent variability of watersheds structures and mechanistic models demands too many data to be used as routine tools. The aim of this study is then to develop a catchment scale pesticide runoff risk assessment tool to help catchment managers to identify risky situations. We developed two indicators: one to assess agricultural impact on pesticide runoff risk at a field scale and the other field spatial position impact on runoff route from the field to the hydrological network. Aggregating those two indicators lead us to assess catchment fields pesticide runoff risk and allows comparing agronomical or climatic scenarios. We based both indicators on modelling assuming that processes described by model make possible to explore wide factors variation ranges and to build databases on which indicators are developed

This master thesis deals with the methods of measurement of singlet oxygen steady state concentrations in surface water and the factors affecting this concentration. The first part of this work shows theoretical background and an introduction to photochemistry of surface water with respect to the reactive oxygen species. The second part describes the methodology of conducted experiments and discuss its results with respect to current literature.

Análises hidroquímicas e isotópicas de oxigênio-18, deutério e carbono inorgânico dissolvido foram utilizados para a caracterização dos recursos hídricos superficiais e subterrâneos no entorno da Lagoa da Confusão - Tocantins. O objetivo principal do trabalho é caracterizar e compreender a dinâmica dos recursos hídricos superficiais e subterrâneos da região a partir de suas características geoquímicas e isotópicas. Para isso, foi realizada a caracterização hidroquímica e avaliação da qualidade das águas, englobando conhecimentos da geoquímica do aquífero para entender a dinâmica das águas, ter um diagnóstico da área e auxiliar a gestão dos recursos hídricos da região. A dissertação apresenta os resultados do artigo intitulado “Caracterização hidroquímica das águas superficiais e subterrâneas no entorno da Lagoa da Confusão, Tocantins, Brasil”. Nesse estudo, análises hidroquímicas foram aplicadas para determinar as características das águas superficiais e subterrâneas e suas relações com o meio, na região da Lagoa da Confusão. O estudo permitiu identificar os tipos hidrogeoquímicos predominantes, que contemplam águas bicabornatadas cálcicas ou magnesianas, sendo constado a dominância de espécies iônicas de HCO3 - , Ca2+ e Mg2+. Os resultados demonstram que as águas da área são influenciadas pelas formações geológicas e pelo uso e ocupação dos solos, sendo o estudo da hidroquímica uma importante ferramenta para conhecimento, gestão e monitoramento dos recursos hídricos da região. Apresenta-se também nesse estudo, os resultados do artigo intitulado “Isótopos Estáveis Aplicados ao Estudo dos Fluxos Hídricos no Entorno da Lagoa da Confusão, TO, Brasil”. Por meio desse trabalho, verificou-se que a dinâmica de fluxo e o pouco tempo de confinamento indicado pela composição isotópica das águas subterrâneas estão intimamente relacionados às características ambientais e geológicas da área. Os resultados das análises de δ18O e δD evidenciam a existência do sistema cárstico que favorece uma rápida circulação dos fluxos hídricos, e determina as características hidroquímicas da água. Para as águas superficiais obteve-se para as amostras analisadas no rio Urubu e na Lagoa da Confusão valores superiores às águas subterrâneas. Verificou-se uma interação entre as águas superficiais e subterrâneas da área, sendo os recursos hídricos superficiais abastecidos em períodos de estiagem por águas subterrâneas. Os valores da razão isotópica de carbono inorgânico dissolvido (δ13CCID) foram predominantemente negativos, indicando uma maior contribuição de processos de dissolução de carbonatos por H2CO3. Os resultados das análises isotópicas caracterizam a presença de um aquífero cárstico na área de estudo, na qual a composição química da água é alterada pela interação água-rocha e dissolução das rochas carbonáticas, esse sistema ainda evidenciado pela ocorrência de cavernas e dolinas na área estudada. De forma geral, o estudo mostrou que a dinâmica e composição das águas superficiais e subterrâneas do entorno da Lagoa da Confusão são determinadas pelas características geológicas e pelo uso e ocupação dos solos, sendo o estudo uma importante ferramenta para conhecimento e monitoramento dos recursos hídricos da região. / Hydrochemical and isotopic analyzes of oxygen-18, deuterium and dissolved inorganic carbon were used to characterize surface water and groundwater resources near Lagoa da Confusão - Tocantins. The study main objective is to characterize and understand the dynamics of the superficial and groundwater resources of the region based on their geochemical and isotopic characteristics. To perform the study, it was carried out a hydrochemical characterization and water quality assessment. Both analyzes took into consideration the geochemistry of the aquifer to understand water dynamics as well as to get a more detailed overview of the study area and to help with water management resources in the region. The dissertation presents the results of the article entitled "Hydrochemical characterization of surface and groundwater in the surroundings of Lagoa da Confusão, Tocantins, Brazil". In that study, hydrochemical analyzes were applied to determine surface and groundwater characteristics likewise their interactions with the nearby environment in the Lagoa da Confusão region. The study identified the predominant hydrogeochemical types that can be found in calcic or magnesian bicarbonate water; as such, it observed the dominance of ionic species of HCO3 - , Ca2+ and Mg2+. The results show that the water in the study area is influenced by the local geological formations as well as the land use and occupation of it; therefore, the study of hydrochemistry is an important tool for the study, management and monitoring of water resources in the region. The results of the article entitled "Stable Isotopes Applied to the Study of Water Flows in the Confusion Lagoon Environment, TO, Brazil" are also presented in this study. The research verified that the dynamic flow and the short time confinement, which it was indicated by the isotopic composition of the groundwater, are closely related to the environmental and geological characteristics of the study area. The results of the δ18O and δD analyzes show the existence of a karstic system that contribute to a fast water flow, and it determines the hydrochemical characteristics of the water. For surface water, it was obtained higher values than those from groundwater samples from the Urubu river and Lagoa da Confusão. There was an interaction between surface and groundwater of the study area, since it noticed that surface water resources have been supplied by groundwater sources during drought periods. The values of the isotopic ratio of dissolved inorganic carbon (δ13CCID) were predominantly negative, indicating a greater contribution of carbonate dissolution processes by H2CO3. The results of the isotopic analyzes characterize the presence of a karst aquifer in the study area, in which the chemical composition of the water is altered by the water-rock interaction and the dissolution of the carbonate rocks; besides that, the occurrence of caves and dolines in the study area evidences of those processes. Therefore, the study showed that the dynamics and composition of the surface and groundwater surrounding the Confusion Lagoon are determined by the geological characteristics and the land use and occupation; thus, the result of the study are an important tool for understanding and monitoring the water resources in that region.

Made available in DSpace on 2017-07-24T19:38:07Z (GMT). No. of bitstreams: 1 Ariane Caroline Ribicki.pdf: 2450213 bytes, checksum: d3a3cb87c46173aedb006d302de92a80 (MD5) Previous issue date: 2013-03-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The domestic sewage discharge and decomposition of plants and animals are the most common sources of organic matter in the aquatic environment and their presence deserves special attention, it is the main polluter of surface waters, which consist primarily of biomolecules such as proteins, carbohydrates and lipids. Thus, this work aimed to study the relationship between organic matter and biomolecules on watercourses Pitangui River basin, which are influenced by varying order, such as streams that flow into these watercourses, an effluent discharge of SANEPAR Wastewater Treatment Effluents (WTE) and influences of agricultural and urban areas. For this, the samples were collected weekly from February to August 2012 totaling 22 samples in 5 sites located in Pilão de Pedra Stream, Verde River and Pitangui River. The parameters determined were water temperature, DO, BOD, COD, TP, OP, TKN, proteins, carbohydrates and lipids. The results were analyzed using statistical tests and analyzes as the Scott-Knott, Pearson’s matrices and Principal Component Analysis (PCA) for each sampling site. By Scott-Knott was observed that site 3 presented the highest average for most parameters and statistical differences, due to the WTE effluent discharge. Sites 1 and 2 were statistically equal for most parameters, as well as between sites 4 and 5. By Pearson’s correlations, it was possible to determine the influence of large biological growth and organic matter decomposition in the sampling sites. PCA showed similar results to the Pearson’s correlations results, identifying the rainfall as one of the significant influences for the Pilão de Pedra Stream and Verde River samples. / O lançamento de efluentes domésticos e a decomposição de plantas e animais são as fontes mais comuns de matéria orgânica no ambiente aquático e a sua presença merece especial atenção, pois é a principal poluidora de águas superficiais, sendo constituída basicamente por biomoléculas como proteínas, carboidratos e lipídios. Com isso, este trabalho teve como objetivo principal estudar a relação entre a matéria orgânica e biomoléculas presentes em cursos d’ água da bacia do Rio Pitangui, que sofrem influência de ordem variada, como arroios que deságuam nesses cursos d’ água, lançamento de efluentes de uma Estação de Tratamento de Efluentes da SANEPAR (ETE), influências de áreas agrícolas e aglomerações urbanas. Para tanto, as coletas foram feitas semanalmente, de fevereiro a agosto de 2012 totalizando 22 coletas em 5 pontos localizados no Arroio Pilão de Pedra, Rio Verde e Rio Pitangui. Os parâmetros determinados foram temperatura da água, OD, DBO, DQO, PT, PO, NTK, proteínas, carboidratos e lipídios. Os resultados foram analisados por meio de testes estatísticos como o Scott- Knott, matrizes de Pearson e Análise por Componentes Principais (PCA) para cada ponto amostral. Pelo teste de Scott- Knott foi observado que o ponto 3 apresentou as maiores médias para a maioria dos parâmetros e diferenças estatísticas, devido ao lançamento dos efluentes da ETE. Os pontos 1 e 2 foram iguais estatisticamente para a maioria dos parâmetros, bem como entre os pontos 4 e 5. Pelas correlações de Pearson, foi possível determinar a grande influência do crescimento biológico e da decomposição da matéria orgânica nos pontos de amostragem. A análise multivariada por PCA mostrou resultados semelhantes aos resultados das correlações de Pearson, identificando a pluviometria como uma das influências significativas para as amostras do Arroio Pilão de Pedra e Rio Verde.

In many numerical weather prediction models, the presence of lakes is simulated crudely, with their effect being neglected in the resulting simulations. However, it has been shown how lakes effect not only their surrounding climate directly, but have an effect to the overall weather evolution and ecosystem. It is therefore vital to improve existing models to take lakes into account, by coupling with smaller models specificaly compiled for a reas with lakes. There have been several sophisticated models to parameterizelakes in a geographical area, which are, on the other hand, computationally expensive and time consuming. A model built specifically on simple physical assumptions, named FLake, aims to provide a solution that is not heavy computationally, but is accurate enough and contains all the necessary physics surrounding the heat budget and temperature of a given lake. For this project, FLake was tried on a lake close to Uppsala, named Erken, where the validity of the model was tested against data archives from Erken Laboratory’s measurement tower. The resulting simulations were very promising regarding the water temperatures, as well as giving out acceptable results for the surface heat fluxes above the lake and the duration of the ice period, as it was modeled by FLake and compared with ice data archives.

Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2017-08-16T15:50:35Z No. of bitstreams: 1 DISSERTAÇÃO - FINAL.pdf: 7338222 bytes, checksum: 196e18ecc90db3ce259dd90644d24860 (MD5) / Made available in DSpace on 2017-08-16T15:50:35Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO - FINAL.pdf: 7338222 bytes, checksum: 196e18ecc90db3ce259dd90644d24860 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geoquímica, Niterói, RJ / A presente pesquisa hidrogeoquímica teve como intuito caracterizar o comportamento físico-químico, a composição mineralógica, a quantificação e composição química dos sedimentos e da água da microbacia do Córrego do Bule. Região essa, alvo de exploração mineral de sulfeto de antimônio nas décadas de 1920 e 1930, na qual hoje se encontra complemente soterrada. A microbacia está localizada na porção centro-sul do Sinclinal Dom Bosco, sul do Quadrilátero Ferrífero. Foram utilizadas diversas técnicas analíticas, juntamente com informações fisiográficas, geológicas e interpretações dos resultados estatísticos, que permitiram a determinação dos agentes controladores e carreadores, o desenvolvimento de backgrounds e a identificação de anomalias. Além disso, foi realizada a medição da vazão, a análise dos parâmetros de qualidade de água, quantificação da composição iônica e os metais dissolvidos na água. A composição mineralógica foi caracterizada a partir das análises de DRX sobre os sedimentos, onde se obteve a identificação da presença predominante de óxidos de ferro, como a goetita, hematita, bem como, caulinita e quartzo. Em sua composição química, destacam-se as altas concentrações de ferro justificada pela litologia local e o empobrecimento em alumínio, o qual reflete um alto grau de maturidade e/ou avançados processos de intemperismo químico. Há também a presença dos elementos traços como As, Cu, Pb, Sb e Zn, sendo estes associados a presença de mineralizações auríferas mesotermais hospedadas em greenstone belts e os elementos As, Co, Cr, Mn, Ni e Sb na composição de lateritas. A influência antrópica na área de estudo é praticamente nula. Isso se deve à microbacia estar contida em uma área de proteção ambiental permanente e longe de grandes centros urbanos e áreas de agropecuária. Portanto, é possível afirmar que as concentrações de metais são provenientes de fontes naturais / This hydrogeochemical research aimed to characterize the physicochemical behavior, mineralogical composition, quantification and chemical composition of sediments and water in the watershed of the Corrego do Bule. This area, which today is completely buried, was mined for antimony sulfide in the decades of 1920s and 1930s. The watershed is in the center-south of the Syncline Dom Bosco, south from the Iron Quadrangle. Several analytical techniques were used together with physiographic geological and statistical data interpretation. This allowed us to determine the controlling agents and carriers, the development of backgrounds and the identification of anomalies. In addition, we measured the flow pressure, analyzed the water quality parameters, quantified the ionic composition and dissolved metals in the water. The mineralogical composition was characterized by the XRD analyzes on the sediments where it was possible to identify the predominant presence of iron oxides, such as goethite, hematite, as well as, kaolinite and quartz. On its chemical composition, the high concentrations of iron are justified by the local lithology and the impoverishment in aluminum which reflects a high degree of maturity and / or advanced processes of chemical weathering. There are also the presence of some elements traces such as As, Cu, Pb, Sb and Zn, which are associated with the presence of mesothermal aureation minerals in greenstone belts and the elements As, Co, Cr, Mn, Ni and Sb in laterites. The antropic influence in the study area is practically null. This is because the watershed is contained in an area of permanent environmental protection and away from large urban centers and agricultural areas. In this way, it is possible to state that the concentrations of metals come from natural sources

Submitted by Verena Bastos (verena@uefs.br) on 2015-08-05T22:27:36Z No. of bitstreams: 1 Dissertacao_FINAL.pdf: 10730676 bytes, checksum: 8d2235818b9b2636a1d0590bbb36fe1a (MD5) / Made available in DSpace on 2015-08-05T22:27:36Z (GMT). No. of bitstreams: 1 Dissertacao_FINAL.pdf: 10730676 bytes, checksum: 8d2235818b9b2636a1d0590bbb36fe1a (MD5) Previous issue date: 2013-03-15 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The Suba? river basin (BRS), whose source is located in Feira de Santana-BA and its mouth in the Bay of All Saints, poses serious environmental impacts in its main watercourses arising from dumping of domestic and industrial effluents, agricultural and extractive activities. This study aims to perform analysis of physicochemical processes and microbial surface water has not been studied in the stretch along the main river channel Suba? and analysis of processes for use and occupation of the soil surrounding the BRS. Use map and land use was generated from the RapidEye satellite image, 2010, together with field surveys and through the software ArcGis 9.3, Global Mapper 11 and Envi 4.0, identified five main classes: urban area, bodies water, bare soil, vegetation and agriculture, of which agriculture accounts for 77.6% of the entire basin area, bordering the main river from its source to its mouth. 13 points were defined water collection, geo-referenced throughout the course of the river and Suba? samples were collected in December 2011, April 2012 and November 2012. The results were analyzed based on CONAMA Resolution 357/05 and 430/12 for Class 2 waters sweet, consistent with the proposed framework for the spring and held Pearson correlation to unify the possible relationships of heavy metals and physico- Chemical. The results demonstrate the analyzed parameters, dissolved oxygen (DO), biochemical oxygen demand (BOD), turbidity and phosphate are above the maximum allowable values in most monitoring points, compared with the values of legislation and total coliforms and thermotolerant at all collection points and in all samples had values above that indicated by the legislation. Heavy metals, only Cd and Cr were not detected in any of the monitoring points and none of the collections. The highest concentrations of metals found in descending order were Zn> Mn> Cu> Pb> Ni. The Pearson correlation demonstrated a strong relationship between the physico-chemical parameters and metals. These results are related to the fact that water bodies receiving domestic and industrial effluents from various activities in the area of BRS. By the results it is concluded that the river Suba? presents a high level of degradation in the quality of its waters and represents a health risk for the population living around it. This research will provide subsidy for implementation of actions aimed at the rational use of water resources of BRS, and contribute to scientific studies that allow a better understanding of the real situation of this important and strategic industrial region of Bahia state. / A bacia do rio Suba? (BRS), cuja nascente localiza-se em Feira de Santana-BA e sua foz na Ba?a de Todos os Santos, apresenta s?rios impactos ambientais nos seus principais cursos d??gua decorrentes do despejo de efluentes dom?sticos e industriais, atividades agropecu?ria e extrativista. O presente estudo teve como objetivo realizar an?lise dos processos f?sico-qu?micos e microbiol?gico da ?gua superficial no trecho ainda n?o estudado ao longo do canal principal do rio Suba? e an?lise dos processos de uso e ocupa??o do solo no entorno da BRS. O mapa de uso e ocupa??o do solo foi gerado a partir da imagem do sat?lite RapidEye, 2010, aliado com os levantamentos de campo e atrav?s dos softwares ArcGis 9.3, Global Mapper 11 e Envi 4.0, sendo identificados cinco classes principais: ?rea urbana, corpos d??gua, solo exposto, vegeta??o e agropecu?ria, das quais a agropecu?ria corresponde a 77,6% de toda ?rea da bacia, margeando o rio principal desde sua nascente at? a sua foz. Foram definidos 13 pontos de coleta de ?gua, georeferenciados ao longo do curso do rio Suba? e as coletas foram realizadas em dezembro de 2011, abril de 2012 e novembro de 2012. Os resultados foram analisados com base na resolu??o CONAMA 357/05 e 430/12 para ?guas doce Classe 2, condizentes com o enquadramento proposto para o manancial e realizou-se correla??o de Pearson para unificar as poss?veis rela??es dos metais pesados e dos par?metros f?sico - qu?micos. Os resultados dos par?metros analisados demonstraram que oxig?nio dissolvido (OD), demanda bioqu?mica de oxig?nio (DBO), turbidez e fosfato est?o acima dos valores estabelecidos pela legisla??o, na maioria dos pontos de monitoramento, e os coliformes totais e termotolerantes, em todos os pontos e em todas as coletas apresentaram valores acima dos indicados pela legisla??o vigente. Dos metais pesados, apenas Cd e Cr n?o foram detectados em nenhum dos pontos de monitoramento e em nenhuma das coletas. As maiores concentra??es de metais encontrados em ordem decrescente foram Zn>Mn>Cu>Pb>Ni. A correla??o de Pearson demonstrou forte rela??o entre os par?metros f?sico-qu?micos e os metais. Estes resultados est?o relacionados ao fato dos corpos d??gua receberem efluentes dom?sticos e industriais de diversas atividades desenvolvidas na ?rea da BRS. Pelos resultados encontrados conclui-se que o rio Suba? apresenta um alto n?vel de degrada??o da qualidade de suas ?guas e representa um risco de sa?de para popula??o residente em seu entorno. Esta pesquisa dar? subs?dio para implementa??o de a??es que visem o uso racional dos recursos h?dricos da BRS, al?m de contribuir com estudos cient?ficos que permitam um melhor conhecimento da real situa??o dessa importante e estrat?gica regi?o industrial do estado da Bahia.

Background: The leading cause of surface water impairment in United States’ rivers and streams is pathogen contamination. Although use of fecal indicators has reduced human health risk, current approaches to identify and reduce exposure can be improved. One important knowledge gap within exposure assessment is characterization of complex fate and transport processes of fecal pollution. Novel modeling processes can inform watershed decision-making to improve exposure assessment. Methods: We used the ecological model, Maxent, and the fecal indicator bacterium Escherichia coli to identify environmental factors associated with surface water impairment. Samples were collected August, November, February, and May for 8 years on Sinking Creek in Northeast Tennessee and analyzed for 10 water quality parameters and E. coli concentrations. Univariate and multivariate models estimated probability of impairment given the water quality parameters. Model performance was assessed using area under the receiving operating characteristic (AUC) and prediction accuracy, defined as the model’s ability to predict both true positives (impairment) and true negatives (compliance). Univariate models generated action values, or environmental thresholds, to indicate potential E. coli impairment based on a single parameter. Multivariate models predicted probability of impairment given a suite of environmental variables, and jack-knife sensitivity analysis removed unresponsive variables to elicit a set of the most responsive parameters. Results: Water temperature univariate models performed best as indicated by AUC, but alkalinity models were the most accurate at correctly classifying impairment. Sensitivity analysis revealed that models were most sensitive to removal of specific conductance. Other sensitive variables included water temperature, dissolved oxygen, discharge, and NO3. The removal of dissolved oxygen improved model performance based on testing AUC, justifying development of two optimized multivariate models; a 5-variable model including all sensitive parameters, and a 4-variable model that excluded dissolved oxygen. Discussion: Results suggest that E. coli impairment in Sinking Creek is influenced by seasonality and agricultural run-off, stressing the need for multi-month sampling along a stream continuum. Although discharge was not predictive of E. coli impairment alone, its interactive effect stresses the importance of both flow dependent and independent processes associated with E. coli impairment. This research also highlights the interactions between nutrient and fecal pollution, a key consideration for watersheds with multiple synergistic impairments. Although one indicator cannot mimic the plethora of existing pathogens in water, incorporating modeling can fine tune an indicator’s utility, providing information concerning fate, transport, and source of fecal pollution while prioritizing resources and increasing confidence in decision making. Methods We used the ecological model, Maxent, and the fecal indicator bacterium Escherichia coli to identify environmental factors associated with surface water impairment. Samples were collected August, November, February, and May for 8 years on Sinking Creek in Northeast Tennessee and analyzed for 10 water quality parameters and E. coli concentrations. Univariate and multivariate models estimated probability of impairment given the water quality parameters. Model performance was assessed using area under the receiving operating characteristic (AUC) and prediction accuracy, defined as the model’s ability to predict both true positives (impairment) and true negatives (compliance). Univariate models generated action values, or environmental thresholds, to indicate potential E. coli impairment based on a single parameter. Multivariate models predicted probability of impairment given a suite of environmental variables, and jack-knife sensitivity analysis removed unresponsive variables to elicit a set of the most responsive parameters. Results Water temperature univariate models performed best as indicated by AUC, but alkalinity models were the most accurate at correctly classifying impairment. Sensitivity analysis revealed that models were most sensitive to removal of specific conductance. Other sensitive variables included water temperature, dissolved oxygen, discharge, and NO3. The removal of dissolved oxygen improved model performance based on testing AUC, justifying development of two optimized multivariate models; a 5-variable model including all sensitive parameters, and a 4-variable model that excluded dissolved oxygen. Discussion Results suggest that E. coli impairment in Sinking Creek is influenced by seasonality and agricultural run-off, stressing the need for multi-month sampling along a stream continuum. Although discharge was not predictive of E. coli impairment alone, its interactive effect stresses the importance of both flow dependent and independent processes associated with E. coli impairment. This research also highlights the interactions between nutrient and fecal pollution, a key consideration for watersheds with multiple synergistic impairments. Although one indicator cannot mimic theplethora of existing pathogens in water, incorporating modeling can fine tune an indicator’s utility, providing information concerning fate, transport, and source of fecal pollution while prioritizing resources and increasing confidence in decision making.