Abstract A system with the combination of upflow anaerobic sludge blanket (UASB) reactor and constructed wetlands (CWLs) has not yet been applied for cleaning river water polluted by sewage and swine wastewaters. In this study, a pilot system with an UASB reactor (effective working volume 4.0 m3) combined with two CWL reactors (effective working volumes 4.8 and 5.4 m3 for CWL-1 and CWL-2, respectively) was used to test the feasibility for treating wastewater sampled from the Wu-Luo River. The river is located in Ping-Tong County of southern Taiwan and has long been polluted by untreated domestic and partially treated swine wastewaters and is among the most polluted rivers in Taiwan. A control system without the UASB reactor and with the CWL-1 and CWL-2 was also tested in parallel to the test system. In the test system, the UASB reactor was seeded with an anaerobic sludge for sewage treatment and CWL-1 and CWL-2 of both the test and control systems were planted with emergent macrophyte (Typha angustifolia L.) and floating macrophyte (Pistia stratiotes L.), respectively. In general, it requires hydraulic retention times (HRT) of 1-5 days for polluted waters in CWLs to obtain clarified ones. In the present study, HRT of the test water in the system was reduced from around 34 to 11 hours to examine the clarification effect. Results indicated that the influent water has the following average qualities (unit in mg/L): total COD (CODt) 61, BOD 14, suspended solids (SS) 156, total-N 24, ammonia-N 12, nitrate-N 3.9, nitrite-N 0.92, and total-P (TP) 41. Results also indicate with a total HRT of 11.3 hrs, the test system (UASB-CWL1-CML2) could achieve average removals of 62% CODt, 56% BOD, 75% SS, 37% TN, 44% ammonia-N, 54% nitrate-N, 47% nitrite-N, and 61% TP from the influent water. The effluent water has the following average qualities (unit in mg/L):CODt 19, BOD 6.1, SS 15, TN 15, ammonia-N 7.5, nitrate-N 1.8, nitrite-N 0.49, and TP 1.7. The study indicates that the UASB could act as a preliminary device for sedimentation of most of the influent suspended solids and hence preventing the accumulation of sludge in the following CWLs.

Au cours des dernières années, divers travaux visant à identifier et à quantifier les sous-produits organohalogénés (SPOX) issus du traitement des eaux brutes de rivières à la monochloramine ont été menés. Un effort particulier a été porté sur le suivi des sous-produits organohalogénés réglementés et/ou connus et au paramètre analytique AOX (composés organohalogénés adsorbables sur charbon actif). Ce paramètre permet d’estimer la quantité totale de sous-produits organohalogénés générés.Un état des lieux récent montre qu’en dépit du nombre important de ces composés sur des échantillons d’eau « réels », le pourcentage de ces sous-produits identifiés imputables au traitement à la monochloramine reste très faible.Le travail réalisé dans la thèse s’inscrit dans la continuité des travaux menés par EDF R&D sur la spéciation des SPOX constitutifs d’AOX, selon une démarche analytique interconnectée. Cette dernière a permis la réduction d’incertitudes liées à la manière d’établissement du bilan de matière par (1) la mise en place de protocoles efficaces d’extraction et d’enrichissement des SPOX sur phase solide, (2) le développement de méthodes d’analyse sensibles permettant de doser simultanément plusieurs SPOX ou familles de SPOX connus, (3) la fiabilisation de la méthode de mesure des AOX en améliorant son étape de préparation d’échantillon et le développement d’une méthode d’analyse permettant d’établir le taux d’incorporation des différents halogénures (Cl, Br, I) dans les AOX, et (4) la réalisation d’essais de « screening » non ciblé par GC-MS et LC-MS ainsi que l’analyse en haute résolution par le FT-ICR/MS, pour l’identification des SPOX de haut poids moléculaire.Cette démarche a été appliquée sur des échantillons d’eau réels et a permis un gain de sensibilité par rapport aux méthodes actuelles, ainsi que l’identification de nouveaux SPOX, non répertoriés dans les études antérieures d’EDF R&D. / Over the last years, various studies have been carried out to identify and quantify the organohalogen by-products (OXBPs) resulting from the treatment of river waters with monochloramine. A particular effort was made to monitor the regulated and/or known organohalogen by-products with the analytical parameter AOX (Adsorbable Organic Halides). This parameter estimate the quantity of organohalogen by-products generated.A recent inventory shows that despite the large number of these compounds on "real" water samples, the percentage of these identified by-products attributable to monochloramine treatment remains very low.The thesis project is a continuation of previous studies carried out by EDF R&D on the speciation of OXBPs constituents of AOX, according to an interconnected analytical approach. This latter allowed the reduction of uncertainties related to how the material balance was established : (1) setting up efficient extraction and enrichment protocols for OXBPs on solid phase, (2) the development of sensitive analytical methods for monitoring simultaneously several known OXBPs, (3) improving the reliability of the AOX measurement method by improving its sample preparation step and developing a method of analyzing Analysis in order to establish the rate of incorporation of the various halides (Cl, Br, I) in AOX, and (4) non-targeted screening tests by GC-MS and LC-MS, as well as analysis in high resolution by FT-ICR/MS for the identification of OXBPs with high molecular weight.This approach was applied to real water samples and increased sensitivity to current methods, as well as the identification of new OXBPs not listed in previous EDF R&D studies.

Rising atmospheric CO2 concentrations have motivated efforts to better quantify reservoirs and fluxes of Earth’s carbon. Of these fluxes from the atmosphere, one that has received relatively little attention is the atmospheric carbon sink associated with carbonate mineral dissolution. Osterhoudt (2014) and Salley (2016) explored new normalization techniques to improve and standardize a process for measuring this flux over large river basins. The present research extends this work to the 490,600 km2 Ohio River drainage basin and 11 subbasins. The study estimated the DIC flux leaving these basins between October 1, 2013, and September 30, 2014, based on secondary hydrogeochemical, geologic, and climatic data. The total annual DIC flux for the Ohio River basin was estimated to be 7.54 x 1012 g carbon (C). The time-volume normalized value of DIC flux for the Ohio basin was 3.36 x 108 g C/km3 day, where the km3 refers to the amount of water available during the year. This was within 71.4% agreement with the Barren River data (Salley, 2016) and within 63.9% agreement with the Green River data (Osterhoudt, 2014). In general, normalized DIC flux values of sub-basins containing at least modest amounts (more than 8%) of exposed carbonates (Tennessee, Cumberland, Green, Kentucky, Licking, Monongahela, and Allegheny) were in strong agreement with the normalized DIC flux of the Ohio River basin, whereas inclusion of basins with little or no near surface carbonates (Wabash, Great Miami, Scioto and Kanawha) yielded poor agreement. Regression analysis yielded strong agreement between DIC flux and the normalization parameters for the carbonate-bearing sub-basins (R2 = 0.97, p =

Das Wasser der Elbe auf der Höhe von Dresden enthält anorganische Kolloidpartikel, deren Partikelgrößenverteilung nahezu den gesamten kolloidalen Definitionsbereich (1 nm bis 1 µm) überstreicht und die vor allem aus sekundär ausgeschiedener amorpher Kieselsäure sowie aus Oxyhydroxiden des Fe, Al und Mn bestehen. Als wichtigstes Schwermetall führen sie Zn. Ihre Konzentration liegt unter 5×10-1 mg/l, um etwa Faktor 30 unter der Konzentration der Schwebstoffe des Elbwassers (Partikel >1 µm). Wegen ihrer hohen spezifischen Oberfläche sind die Kolloidpartikel als potentielle Träger für Schadstoffe trotz dieser geringeren Massekonzentration nicht gegenüber den Schwebstoffen zu vernachlässigen. Die in der Elbe gemessene Partikelgrößenverteilung ähnelt derjenigen, die zu einem früheren Zeitpunkt im Rhein gefunden worden war. Auch die chemische Zusammensetzung der Kolloidpartikel in der Elbe ist der der Partikel des Rheins ähnlich. Die Konzentration der Kolloidpartikel in der Elbe war aber um Faktor 5 bis 10 höher als im Rhein. Grund für letzteres ist wahrscheinlich der höhere Gehalt des Elbwassers an gelöstem Kohlenstoff (DOC). Im "Bulk" eines Flusses sind kolloidgetragene Schadstoffe - anders als schwebstoffgetragene - vermutlich fast genauso mobil wie echt gelöste. Unterschiede zwischen den Transportgeschwindigkeiten der kolloidgetragenen und der echt gelösten Spurenstoffe treten in bestimmten Situationen auf, in denen das Wasser den "Bulk" eines Flusses verlässt (Sickerbereich unter dem Fluss, Ästuar). Es werden Schlussfolgerungen über die Rolle von Kolloidpartikeln im Ökosystem eines Flusses gezogen und noch bestehende Forschungsdesiderate benannt.

This thesis is to study the feasibility of using river water from Gavleån in the cooling system of University of Gävle. The project is proposed by the campus service manager Akademiska Hus AB which intended to replace the current cooling production system with the water cooling system to reduce the electricity cost in cooling production. The river by direct distance is 600 meters from the university, the river water is to be extracted from the river via a pump house, flow through pipeline buried underground and delivered to the equipment house of Akademiska Hus.   Most water source cooling prefer water body with decent depth which contain low temperature water to use as free cooling source, but the issue that limits the practice is, the decent depth is not a very common feature of most water body near or within urban area. Like Gavleån which has an average depth of not over five meters while the sufficient depth is over 50 meters for the least or 70 meters to 100 meters often. So study the potential of using rather high temperature water from shallow water body can be of high interest for most cooling consumers.   The thesis progressed through the work in five parts. To introduce cooling in general starting with literature review, the concept, the mechanism, the device for end use and production, the demand of cooling and the reason behind it. Followed by case studies of water source cooling projects worldwide, which is mostly deep water source cooling, and another case of the local hospital cooling system that extract water from Gavleån, demonstrate the use of shallow water body in assisting cooling production, it gives some insights how the potential if similar system is to be implemented in the campus, which is mounted on the same river. Several tours to the hospital were taken to acquire data and understanding of the system.   Then the water temperature measurement from Gavleån in 2014 summer is presented. The measurement was carried out at a small dock by the river side during July to September of 2014. The measurements show the temperature of river water has been increasing which limits free cooling throughout the year, additional refrigerator is required to produce chilled water. The river water, in the hot seasons is used as cooler for the refrigerator and in cold season can be used for free cooling directly. Simulation of IDA-ICE gives the cooling demand of modelled building blocks, the output of cooling production season (consistent with the hot seasons) matches the cooling consumption data from Akademiska Hus by an error of 1% (414743 kWh of simulated result to 415270 kWh in documentation of Akademiska Hus).   To meet the demand of cooling and select more cost-effective refrigerator type, consumption and COP (COP: Coefficient of Performance) are calculated for compressor chiller and absorption chiller with basic cooling cycle for both. The results shown compressor chiller has much better performance but also higher consumption in electricity, while absorption chiller has rather low COP value in comparison but the need of energy input is much less given by its major consumption of energy is heat from hot water, already a purchased item by the university from district heating network. Cost-effectiveness wise speaking absorption chiller is a more optional choice. Reasonable values of assumption are largely employed in the calculation to select the better candidate and bring certain errors, which is then exam in sensitivity analysis to weigh the alternative parameter and the outcome from it.   The last part is to estimate the cost of chillers and pipeline, for the concern of minimizing errors due to uncertainty the operation cost, labor cost and future energy price are not included. As the calculation turns out the payback year of the new system can range from 7 to 12 years by different refrigerator setup and pipeline routine design, which is considered within the life time of the chiller and pipeline, also lower than the current cooling cost of the university and therefore concluded as promising investment.   Discussion and conclusion exam and finalize the whole thesis work. For the uncertainties of the calculation, the lack of information and data, which are improvements, can be done in future work. Also the improvements in other perspectives noted in terms of better load management for the cooling production units so the cost of equipment can be reduced, changes in building attachment and cooling device to reduce the demand of cooling, etc. But mostly draw the conclusion that with proper system configuration shallow water body can be helpful in reducing cooling consumption, and be a promising option for cities that have access to such water body.

Millions of people rely upon the Ganges River as a source of water provision and a site of disposal for sewage, solid waste, agricultural runoff and industrial effluent. The river is also a goddess in the Hindu pantheon who is worshipped for her purificatory powers, despite water quality levels that fall far short of standards for use in bathing, washing, and drinking. In recent years, a number of non-governmental organizations (NGOs) have formed to oppose both pollution of the river and the failure of state-run pollution abatement programs. They are joined by an increasingly frequent number of seemingly spontaneous protests held during the large Kumbh Mela festival gatherings at Allahabad, Uttar Pradesh. Led by priests, sadhus and religious leaders, these protestors refuse to participate in the ritual bathing that is central to river worship until local and state officials take action to improve water quality at the site. These events indicate that the politics surrounding pollution abatement in the Ganges River Basin (GRB) are changing and that civil society organizations are struggling to gain greater representation and influence in the processes that shape pollution abatement and water use management in the GRB. This dissertation investigates the growing debate around pollution and pollution abatement in the Ganges River Basin and interprets the struggle over pollution abatement and river water management as a struggle over meaning in which various groups attempt to influence the context and context of local environmental knowledge(s). The research compares abatement efforts, civil society activity, and the "pollution knowledge" and water use practices of water users in three urban centers in the central GRB. An analysis of archival data, policy documents, a survey of water users, and interviews with government officials, NGO leaders and members, and other local scientists and activists conducted during fieldwork in 2008 and 2009. Discussion centers on the meta-discursive productions surrounding public participation and popular "awareness" as precursors to public participation in decisionmaking and policy-making processes. Findings indicate that water users in the GRB are well aware of pollution in the river and that many users exhibit a degree of cognitive dissonance in their pollution knowledge, indicating that a disconnection may exist between the knowledge that guides opinion and the knowledge that guides water use activity. Anti-pollution social movement organizations are found to employ methods and tactics that reflect local contexts of environmental degradation and pollution production, but which ultimately aim to reproduce broads shifts in the ideas, values, and power relations associated with water quality and water use in the Basin. Discussion considers the politics of upstream/downstream relations in shaping pollution abatement measures and the occurrence of "missing movements", or the absence of anti-pollution civil society activity. Research findings contribute to literature on the role of environmental knowledge in shaping the “politics of meaning” around which ideological struggles over natural resource use, access, and conservation are waged.

学位授与大学：京都大学 ; 取得学位: 博士(工学) ; 学位授与年月日: 2007-09-25 ; 学位の種類: 新制・課程博士 ; 学位記番号: 工博第2849号 ; 請求記号: 新制/工/1419 ; 整理番号: 25534 / Understanding river water quantity and quality variation is one of the fundamental requirements for the integrated watershed management. Monitoring is usually preferred to examine and understand the river water quantity and quality, especially focusing on pre-specified objectives. Although monitoring is invaluable in many instances, it is of less use to forecast the foreseeable changes, especially, for the long-term prediction that is usually required by the decision-makers. Therefore, for the decision-making, modeling is widely practiced. Due to the limited understanding of hydrological processes inside a watershed, models often fail to estimate properly, which in worst case could often mislead the targeted plans. Among several aspects, spatial variability such as land cover, topography, soil, geology is believed to affect the overall performance of the model. Such thought lead to the concept of distributed models that were supposed to represent spatial variability through modeling specific variations inside the watershed by using several representative units or grids. In that meaning, distributed models required to identify and assign the values of its parameters to represent the physical processes defined by the governing equations for each grid. Due to the unavailability of required spatial information at appropriate grid sizes, even physically based and conceptually sound distributed models fail to estimate properly thereby offsetting the credibility of distributed models. Therefore, in this study, we set a major objective to develop a new distributed water quantity and water quality model to address some of the stated issues. Major emphasis was given to conceptually sound but simple structure of the model. In addition to that, model aimed to utilize the potential of recent advances in spatial information, such as remote sensing and GIS, to generate and process the spatial data, and to determine the values of its essential parameters. The approach was expected to provide an example that the complexity of the model should be preferred only if the defined processes could be ascertained within some reasonable limit. At the initial stage, several spatial data were collected from different sources and they were processed into raster format, which was one of the essential requirements for the distributed model. Analysis of spatial database indicated that the watershed was characterized by forested parts in the hills, and densely populated urban areas in plains. Rainfall occurred quite frequently but they were of short duration. Besides constructing spatial database, several water quantity and quality surveys were also conducted at different spatial and temporal conditions from 2000 to 2006. The data were mainly used to understand variation patterns of water quantity and quality at both spatial and temporal conditions. Later on, some of the data were also used for the verification of model in study area. 28 water quality indices (WQIs) were observed for each observation, which were mainly utilized to understand the overall variation pattern of river water quality. Initial analysis of flow rate condition of the river showed that the rainfall-runoff responses were quite rapid after the rainfall but such effect appear for very short duration (< 2 days). Then, analysis of variance (ANOVA) and two multivariate analysis techniques (MVA), namely, principle component analysis (PCA) and cluster analysis (CA) were used to explore effectively the river water quality datasets. Analysis showed that the observed covariation among majority of WQIs could be due to the inter-linkages among rainfall pattern, atmospheric deposition of acidic ions, soil and geology of dominant forest areas, topography, and climatic conditions. The identified pattern indicated that there could be close relationship between the biogeochemical processes in the forest areas with both river water quantity and quality variation. A new distributed water quantity and quality model was developed especially focusing on the biophysical characteristics of the watershed. Basic structure of the model was similar to the concept of lumped tank model, which was often credited for its simple and sound conceptual structure. Two storey tanks were conceptualized for each grid, but model also took into consideration of drainage channels in urban areas and natural river channels as rapidly conveying structures. Besides, the model considered all major aspects affecting the estimation of water quantity, such as interception of the rainfall, evapotranspiration loss, surface runoff, sub-surface runoff, and ground water runoff. Compared with the original tank model, major emphasis was given to assign the values major parameters, such as coefficients and storage heights of the outlets, by relating them with the hilly topography of the study area and the variation in land cover, soil, and geology. The model was further integrated with water quality component, which was based on two fundamental assumptions of build-up and wash-off of the WQIs in the environment. Build-up was based on the land cover type and population, while wash off was based on the estimated runoff volume. Remote sensing and GIS techniques were used to assist in the modeling process. At first, remote sensing was mainly focused in the classification of land cover by utilizing seasonal Landsat ETM+ images. In addition to urban and vegetated urban categories, four major forest categories (shaded, deciduous, mixed, and evergreen) were identified. Then leaf area index (Lai) was determined for each vegetation category. Lai was mainly used to determine the rainfall interception by the canopy in the forest areas. In this study, forest areas showed the capacity to intercept as high as 1.2 mm of rainfall, which could be quite important during smaller rainfall events. Remote sensing was further used to determine the transpiration coefficient of the vegetations, which was a major requirement for the estimation of evapotranspiration (Et) loss by the FAO Penman- Monteith method used in the model simulation. Et was estimated even reached more than 4 mm/d in summer months, but it was relatively lower (< 2 mm/d) in the winter months. These facts suggested that consideration of both interception and Et loss in a forested watershed could have significant influence on the estimation of flow rates by the model. At the final stage, model was applied in the study area. Mainly three approaches were considered to assess the estimation by the model. First was conventional approach in which comparison between the observed and estimated data were done considering different spatial and temporal contexts. Assigned values of the parameters gave satisfactory prediction for both water quantity and quality for the selected grid size of 50 m in which the relative error was usually less than 1. The second approach evaluated the model by considering different scale of the grids ranging from 100m to 500m. It was observed that grid resizing usually affected the basin attributed such as slope, outlet height, drainage characteristics following nearly proportionate pattern than other categorical variables such as land cover or geology. Usually same parameter values gave very different prediction level for both magnitude and shape of the hydrographs (or pollutographs), in which increasing grid size was accompanied by the increasing peak event estimation or overall error. The effects were further assessed by changing the values of key parameters for each grid size targeting the minimum differences between the observed and estimated values. Interestingly, the parameters also showed some identifiable (increasing or decreasing) trend with the change in grid size. Particularly, due to the direct effect of predicted runoff on the reference WQIs, its showed more complex variation pattern at different grid sizes. Overall assessment of the distributed model indicated that the model was quite sensitive to the selection of key parameters for different grid sizes. It indicated that the values of calibrated parameters might not give stable result if the scale of input data were changed. It could further indicate that the choice of grid size should be assessed before the actual application of the model considering the spatial variability of the watershed. In the third approach, model was utilized to estimate at different scenarios, namely, rainfall variation and land cover changes. The differences in the estimated results could indicate that the model could be available for the watershed management at different runoff and land cover scenarios in future. / Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第13378号 / 工博第2849号 / 新制||工||1419(附属図書館) / 25534 / UT51-2007-Q779 / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 田中 宏明, 教授 藤井 滋穂, 教授 清水 芳久 / 学位規則第4条第1項該当

Neste estudo, avaliou-se a ocorrência de metais pesados em ambiente fluvial sob influência de curtumes - a bacia hidrográfica dos rios Cadeia e Feitoria (RS, Brasil), focalizando sua origem, distribuição e mobilidade potencial. Trimestralmente, entre julho/1999 e abril/2000, analisaram-se metais e parâmetros complementares em amostras de água e sedimento coletadas em dez locais. Após identificar os contaminantes e locais críticos (cromo e mercúrio, no trecho inferior do rio Feitoria), avaliaram-se também perfis sedimentares verticais e tecido muscular de peixes de fundo (Rineloricaria). As análises de água seguiram recomendações do Standard Methods, enquanto as demais basearam-se principalmente em métodos da agência de proteção ambiental dos Estados Unidos (USEPA) ou Comunidade Européia, buscando prever a disponibilidade potencial dos metais. Utilizou-se estatística descritiva e multivariada na análise dos dados, visando sintetizar informações e subsidiar a futura elaboração de um atlas ambiental. Rastreou-se o risco potencial de danos crônicos não carcinogênicos à saúde humana por ingestão de água e peixes contaminados, conforme metodologia recomendada pela USEPA.A ocorrência de metais vinculou-se a contribuições naturais e antropogênicas, representadas principalmente pela intemperização de basaltos e atividades de curtumes. Influenciada pela proximidade dos curtumes e flutuações na vazão, a qualidade das águas diminuiu ao longo dos rios e no período de menor disponibilidade hídrica (janeiro). Os teores de metais nas águas obedeceram aos padrões da legislação brasileira, exceto para alumínio, ferro e eventualmente manganês. Considerando a ingestão de água em cenário hipotético de alta exposição aos metais estudados (água bruta, picos de contaminação, cromo na forma hexavalente), verificouse uma potencial ausência do risco de efeitos adversos à saúde humana. Entretanto, a área sob maior influência de curtumes demonstrou considerável aumento desse risco, em comparação aos locais de referência. Nos sedimentos, as concentrações de alumínio, cobre, ferro, níquel, manganês, titânio e zinco pareceram refletir níveis basais, ao contrário de cromo e mercúrio, enriquecidos no trecho inferior da bacia. Além de condições de avançado intemperismo, os perfis sedimentares indicaram que as descargas de metais antropogênicos poderiam não estar restritas a atividades pretéritas. A partição dos metais nas fases geoquímicas dos sedimentos revelou maior mobilidade potencial do manganês em toda a bacia, seguido por cromo, na área de concentração de curtumes (predominantemente vinculado à fração oxidável). Ainda que em teores abaixo do recomendado pela Organização Mundial da Saúde (0,5 μg/g), observou-seacúmulo de mercúrio nos peixes, indicando condições ambientais favoráveis à sua metilação. Para reduzir efeitos tóxicos crônicos não carcinogênicos à saúde humana por exposição ao mercúrio, um eventual consumo do peixe estudado deveria ser restrito a 32 g/dia no trecho contaminado. Mesmo não sendo detectado nos peixes, o considerável aumento do teor de cromo nos sedimentos do trecho inferior da bacia sugeriu possibilidade de ocorrerem localmente outros efeitos prejudiciais à biota aquática. Uma potencial mobilização do cromo retido nos sedimentos estaria vinculada às condições redox do meio, enquanto o enxofre poderia condicionar a biodisponibilidade do mercúrio. Estudos posteriores são necessários para melhor entendimento dos processos de mobilização e bioacumulação de metais na área de estudo, envolvendo organismos de diferentes níveis tróficos. / This study evaluated the occurrence of heavy metals in a fluvial environment under the influence of tanneries – the Cadeia and Feitoria rivers watershed (RS, Brazil), phocusing their origin, distribution, and potential mobility. Every three months, between July 1999 and April 2000, selected heavy metals and ancillary parameters were analyzed in water and sediment samples taken at ten sites. After identifying the contaminants and sites of concern (chromium and mercury at the lower reach of Feitoria River), vertical sediment profiles and bottom-fish tissue (Rineloricaria) were also evaluated. Water analyses followed recommendations of the Standard Methods, while the remaining analyses were based mainly on methods from the Environmental Protection Agency of the United States (USEPA) and European Community, searching for estimating the potential availability of metals. Descriptive and multivariate statistics were applied to water and sediment data sets, in order to obtain a synthesis of the environmental diagnosis, and to support the elaboration of an environmental atlas. A risk assessment methodology recommended by USEPA was conducted at a screening level, in order to estimate the potential non-carcinogenic toxic effects to the human health arising from life-time consumption of contaminated water and fish.The results revealed that the heavy metals originate from natural and anthropogenic contributions, mainly resultant from the weathering of basalt rocks and tannery activities. The water quality decreased along both rivers, and during the dry period (January), showing the influence of tannery plants vicinity and flow variations. Except for iron, aluminum, and eventually manganese, heavy metal contents in water were generally in agreement with Brazilian standards. Despite considering the ingestion of water in a hypothetical scenario of high human exposure to the selected metals (untreated water, peaks of contamination, chromium in the hexavalent form), the risk screening indicated a potential absence of adverse toxicological health effects. However, in comparison to the reference sites, this risk considerably increased at the lower reach of Feitoria River, the most affected by tanneries. Concerning sediments, aluminum, copper, iron, nickel, manganese, titanium, and zinc concentrations appeared to reflect the base levels, in opposition to chromium and mercury, which were enriched in the lower part of the basin. The sediment profiles revealed an advanced weathering-stage, and also indicated that the anthropogenic discharges of heavy metals might not be strictly resultant from past activities. The partition of heavy metals among the sediment geochemical phases showed higher mobility of manganese along the basin, followed by chromium in thearea most affected by tanneries (predominantly associated to the oxidizable fraction). Although occurring in levels below the World Health Organization threshold for human consumption (0.5 μg/g), the accumulation of mercury in fish indicated that the prevailing environmental conditions could favor its methylation. Considering the methodology of risk assessment, an eventual consumption of the investigated fish should be restricted to 32 g/day at the lower reach of Feitoria River, in order to reduce the occurrence of non-carcinogenic toxic effects to the human health, arising from oral exposure to mercury. Although chromium was not detected in fish tissue, its considerable enrichment in sediments from the lower part of the basin indicated a potential occurrence of other hazardous effects on aquatic organisms. A potential mobilization of chromium from the contaminated sediments would be associated to the prevailing redox conditions, while the sulfur cycling could influence the bioavailability of mercury. Further research with organisms from distinct trophic levels is needed, in order to better understand the metal bioaccumulation processes that are taking place in the study area.

Neste estudo, avaliou-se a ocorrência de metais pesados em ambiente fluvial sob influência de curtumes - a bacia hidrográfica dos rios Cadeia e Feitoria (RS, Brasil), focalizando sua origem, distribuição e mobilidade potencial. Trimestralmente, entre julho/1999 e abril/2000, analisaram-se metais e parâmetros complementares em amostras de água e sedimento coletadas em dez locais. Após identificar os contaminantes e locais críticos (cromo e mercúrio, no trecho inferior do rio Feitoria), avaliaram-se também perfis sedimentares verticais e tecido muscular de peixes de fundo (Rineloricaria). As análises de água seguiram recomendações do Standard Methods, enquanto as demais basearam-se principalmente em métodos da agência de proteção ambiental dos Estados Unidos (USEPA) ou Comunidade Européia, buscando prever a disponibilidade potencial dos metais. Utilizou-se estatística descritiva e multivariada na análise dos dados, visando sintetizar informações e subsidiar a futura elaboração de um atlas ambiental. Rastreou-se o risco potencial de danos crônicos não carcinogênicos à saúde humana por ingestão de água e peixes contaminados, conforme metodologia recomendada pela USEPA.A ocorrência de metais vinculou-se a contribuições naturais e antropogênicas, representadas principalmente pela intemperização de basaltos e atividades de curtumes. Influenciada pela proximidade dos curtumes e flutuações na vazão, a qualidade das águas diminuiu ao longo dos rios e no período de menor disponibilidade hídrica (janeiro). Os teores de metais nas águas obedeceram aos padrões da legislação brasileira, exceto para alumínio, ferro e eventualmente manganês. Considerando a ingestão de água em cenário hipotético de alta exposição aos metais estudados (água bruta, picos de contaminação, cromo na forma hexavalente), verificouse uma potencial ausência do risco de efeitos adversos à saúde humana. Entretanto, a área sob maior influência de curtumes demonstrou considerável aumento desse risco, em comparação aos locais de referência. Nos sedimentos, as concentrações de alumínio, cobre, ferro, níquel, manganês, titânio e zinco pareceram refletir níveis basais, ao contrário de cromo e mercúrio, enriquecidos no trecho inferior da bacia. Além de condições de avançado intemperismo, os perfis sedimentares indicaram que as descargas de metais antropogênicos poderiam não estar restritas a atividades pretéritas. A partição dos metais nas fases geoquímicas dos sedimentos revelou maior mobilidade potencial do manganês em toda a bacia, seguido por cromo, na área de concentração de curtumes (predominantemente vinculado à fração oxidável). Ainda que em teores abaixo do recomendado pela Organização Mundial da Saúde (0,5 μg/g), observou-seacúmulo de mercúrio nos peixes, indicando condições ambientais favoráveis à sua metilação. Para reduzir efeitos tóxicos crônicos não carcinogênicos à saúde humana por exposição ao mercúrio, um eventual consumo do peixe estudado deveria ser restrito a 32 g/dia no trecho contaminado. Mesmo não sendo detectado nos peixes, o considerável aumento do teor de cromo nos sedimentos do trecho inferior da bacia sugeriu possibilidade de ocorrerem localmente outros efeitos prejudiciais à biota aquática. Uma potencial mobilização do cromo retido nos sedimentos estaria vinculada às condições redox do meio, enquanto o enxofre poderia condicionar a biodisponibilidade do mercúrio. Estudos posteriores são necessários para melhor entendimento dos processos de mobilização e bioacumulação de metais na área de estudo, envolvendo organismos de diferentes níveis tróficos. / This study evaluated the occurrence of heavy metals in a fluvial environment under the influence of tanneries – the Cadeia and Feitoria rivers watershed (RS, Brazil), phocusing their origin, distribution, and potential mobility. Every three months, between July 1999 and April 2000, selected heavy metals and ancillary parameters were analyzed in water and sediment samples taken at ten sites. After identifying the contaminants and sites of concern (chromium and mercury at the lower reach of Feitoria River), vertical sediment profiles and bottom-fish tissue (Rineloricaria) were also evaluated. Water analyses followed recommendations of the Standard Methods, while the remaining analyses were based mainly on methods from the Environmental Protection Agency of the United States (USEPA) and European Community, searching for estimating the potential availability of metals. Descriptive and multivariate statistics were applied to water and sediment data sets, in order to obtain a synthesis of the environmental diagnosis, and to support the elaboration of an environmental atlas. A risk assessment methodology recommended by USEPA was conducted at a screening level, in order to estimate the potential non-carcinogenic toxic effects to the human health arising from life-time consumption of contaminated water and fish.The results revealed that the heavy metals originate from natural and anthropogenic contributions, mainly resultant from the weathering of basalt rocks and tannery activities. The water quality decreased along both rivers, and during the dry period (January), showing the influence of tannery plants vicinity and flow variations. Except for iron, aluminum, and eventually manganese, heavy metal contents in water were generally in agreement with Brazilian standards. Despite considering the ingestion of water in a hypothetical scenario of high human exposure to the selected metals (untreated water, peaks of contamination, chromium in the hexavalent form), the risk screening indicated a potential absence of adverse toxicological health effects. However, in comparison to the reference sites, this risk considerably increased at the lower reach of Feitoria River, the most affected by tanneries. Concerning sediments, aluminum, copper, iron, nickel, manganese, titanium, and zinc concentrations appeared to reflect the base levels, in opposition to chromium and mercury, which were enriched in the lower part of the basin. The sediment profiles revealed an advanced weathering-stage, and also indicated that the anthropogenic discharges of heavy metals might not be strictly resultant from past activities. The partition of heavy metals among the sediment geochemical phases showed higher mobility of manganese along the basin, followed by chromium in thearea most affected by tanneries (predominantly associated to the oxidizable fraction). Although occurring in levels below the World Health Organization threshold for human consumption (0.5 μg/g), the accumulation of mercury in fish indicated that the prevailing environmental conditions could favor its methylation. Considering the methodology of risk assessment, an eventual consumption of the investigated fish should be restricted to 32 g/day at the lower reach of Feitoria River, in order to reduce the occurrence of non-carcinogenic toxic effects to the human health, arising from oral exposure to mercury. Although chromium was not detected in fish tissue, its considerable enrichment in sediments from the lower part of the basin indicated a potential occurrence of other hazardous effects on aquatic organisms. A potential mobilization of chromium from the contaminated sediments would be associated to the prevailing redox conditions, while the sulfur cycling could influence the bioavailability of mercury. Further research with organisms from distinct trophic levels is needed, in order to better understand the metal bioaccumulation processes that are taking place in the study area.

Neste estudo, avaliou-se a ocorrência de metais pesados em ambiente fluvial sob influência de curtumes - a bacia hidrográfica dos rios Cadeia e Feitoria (RS, Brasil), focalizando sua origem, distribuição e mobilidade potencial. Trimestralmente, entre julho/1999 e abril/2000, analisaram-se metais e parâmetros complementares em amostras de água e sedimento coletadas em dez locais. Após identificar os contaminantes e locais críticos (cromo e mercúrio, no trecho inferior do rio Feitoria), avaliaram-se também perfis sedimentares verticais e tecido muscular de peixes de fundo (Rineloricaria). As análises de água seguiram recomendações do Standard Methods, enquanto as demais basearam-se principalmente em métodos da agência de proteção ambiental dos Estados Unidos (USEPA) ou Comunidade Européia, buscando prever a disponibilidade potencial dos metais. Utilizou-se estatística descritiva e multivariada na análise dos dados, visando sintetizar informações e subsidiar a futura elaboração de um atlas ambiental. Rastreou-se o risco potencial de danos crônicos não carcinogênicos à saúde humana por ingestão de água e peixes contaminados, conforme metodologia recomendada pela USEPA.A ocorrência de metais vinculou-se a contribuições naturais e antropogênicas, representadas principalmente pela intemperização de basaltos e atividades de curtumes. Influenciada pela proximidade dos curtumes e flutuações na vazão, a qualidade das águas diminuiu ao longo dos rios e no período de menor disponibilidade hídrica (janeiro). Os teores de metais nas águas obedeceram aos padrões da legislação brasileira, exceto para alumínio, ferro e eventualmente manganês. Considerando a ingestão de água em cenário hipotético de alta exposição aos metais estudados (água bruta, picos de contaminação, cromo na forma hexavalente), verificouse uma potencial ausência do risco de efeitos adversos à saúde humana. Entretanto, a área sob maior influência de curtumes demonstrou considerável aumento desse risco, em comparação aos locais de referência. Nos sedimentos, as concentrações de alumínio, cobre, ferro, níquel, manganês, titânio e zinco pareceram refletir níveis basais, ao contrário de cromo e mercúrio, enriquecidos no trecho inferior da bacia. Além de condições de avançado intemperismo, os perfis sedimentares indicaram que as descargas de metais antropogênicos poderiam não estar restritas a atividades pretéritas. A partição dos metais nas fases geoquímicas dos sedimentos revelou maior mobilidade potencial do manganês em toda a bacia, seguido por cromo, na área de concentração de curtumes (predominantemente vinculado à fração oxidável). Ainda que em teores abaixo do recomendado pela Organização Mundial da Saúde (0,5 μg/g), observou-seacúmulo de mercúrio nos peixes, indicando condições ambientais favoráveis à sua metilação. Para reduzir efeitos tóxicos crônicos não carcinogênicos à saúde humana por exposição ao mercúrio, um eventual consumo do peixe estudado deveria ser restrito a 32 g/dia no trecho contaminado. Mesmo não sendo detectado nos peixes, o considerável aumento do teor de cromo nos sedimentos do trecho inferior da bacia sugeriu possibilidade de ocorrerem localmente outros efeitos prejudiciais à biota aquática. Uma potencial mobilização do cromo retido nos sedimentos estaria vinculada às condições redox do meio, enquanto o enxofre poderia condicionar a biodisponibilidade do mercúrio. Estudos posteriores são necessários para melhor entendimento dos processos de mobilização e bioacumulação de metais na área de estudo, envolvendo organismos de diferentes níveis tróficos. / This study evaluated the occurrence of heavy metals in a fluvial environment under the influence of tanneries – the Cadeia and Feitoria rivers watershed (RS, Brazil), phocusing their origin, distribution, and potential mobility. Every three months, between July 1999 and April 2000, selected heavy metals and ancillary parameters were analyzed in water and sediment samples taken at ten sites. After identifying the contaminants and sites of concern (chromium and mercury at the lower reach of Feitoria River), vertical sediment profiles and bottom-fish tissue (Rineloricaria) were also evaluated. Water analyses followed recommendations of the Standard Methods, while the remaining analyses were based mainly on methods from the Environmental Protection Agency of the United States (USEPA) and European Community, searching for estimating the potential availability of metals. Descriptive and multivariate statistics were applied to water and sediment data sets, in order to obtain a synthesis of the environmental diagnosis, and to support the elaboration of an environmental atlas. A risk assessment methodology recommended by USEPA was conducted at a screening level, in order to estimate the potential non-carcinogenic toxic effects to the human health arising from life-time consumption of contaminated water and fish.The results revealed that the heavy metals originate from natural and anthropogenic contributions, mainly resultant from the weathering of basalt rocks and tannery activities. The water quality decreased along both rivers, and during the dry period (January), showing the influence of tannery plants vicinity and flow variations. Except for iron, aluminum, and eventually manganese, heavy metal contents in water were generally in agreement with Brazilian standards. Despite considering the ingestion of water in a hypothetical scenario of high human exposure to the selected metals (untreated water, peaks of contamination, chromium in the hexavalent form), the risk screening indicated a potential absence of adverse toxicological health effects. However, in comparison to the reference sites, this risk considerably increased at the lower reach of Feitoria River, the most affected by tanneries. Concerning sediments, aluminum, copper, iron, nickel, manganese, titanium, and zinc concentrations appeared to reflect the base levels, in opposition to chromium and mercury, which were enriched in the lower part of the basin. The sediment profiles revealed an advanced weathering-stage, and also indicated that the anthropogenic discharges of heavy metals might not be strictly resultant from past activities. The partition of heavy metals among the sediment geochemical phases showed higher mobility of manganese along the basin, followed by chromium in thearea most affected by tanneries (predominantly associated to the oxidizable fraction). Although occurring in levels below the World Health Organization threshold for human consumption (0.5 μg/g), the accumulation of mercury in fish indicated that the prevailing environmental conditions could favor its methylation. Considering the methodology of risk assessment, an eventual consumption of the investigated fish should be restricted to 32 g/day at the lower reach of Feitoria River, in order to reduce the occurrence of non-carcinogenic toxic effects to the human health, arising from oral exposure to mercury. Although chromium was not detected in fish tissue, its considerable enrichment in sediments from the lower part of the basin indicated a potential occurrence of other hazardous effects on aquatic organisms. A potential mobilization of chromium from the contaminated sediments would be associated to the prevailing redox conditions, while the sulfur cycling could influence the bioavailability of mercury. Further research with organisms from distinct trophic levels is needed, in order to better understand the metal bioaccumulation processes that are taking place in the study area.