Showing papers on "Water quality published in 2010"
TL;DR: In this paper, the main groups of aquatic contaminants, their effects on human health, and approaches to mitigate pollution of freshwater resources are reviewed, particularly on inorganic and organic micropollutants including toxic metals and metalloids as well as a large variety of synthetic organic chemicals.
Abstract: Water quality issues are a major challenge that humanity is facing in the twenty-first century. Here, we review the main groups of aquatic contaminants, their effects on human health, and approaches to mitigate pollution of freshwater resources. Emphasis is placed on chemical pollution, particularly on inorganic and organic micropollutants including toxic metals and metalloids as well as a large variety of synthetic organic chemicals. Some aspects of waterborne diseases and the urgent need for improved sanitation in developing countries are also discussed. The review addresses current scientific advances to cope with the great diversity of pollutants. It is organized along the different temporal and spatial scales of global water pollution. Persistent organic pollutants (POPs) have affected water systems on a global scale for more than five decades; during that time geogenic pollutants, mining operations, and hazardous waste sites have been the most relevant sources of long-term regional and local water pollution. Agricultural chemicals and wastewater sources exert shorter-term effects on regional to local scales.
1,407 citations
TL;DR: Most of the NOM can be removed by coagulation, although, the hydrophobic fraction and high molar mass compounds of NOM are removed more efficiently than hydrophilic fraction and the low molarmass compounds.
1,106 citations
TL;DR: In this article, the role of green roofs in urban drainage considering both management of water quantity and quality is discussed, and the results from investigation of full scale installations as well as from laboratory models are reviewed.
887 citations
TL;DR: It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere.
Abstract: Water is essential to life, but many people do not have access to clean and safe drinking water and many die of waterborne bacterial infections. In this review a general characterization of the most important bacterial diseases transmitted through water— cholera, typhoid fever and bacillary dysentery—is presented, focusing on the biology and ecology of the causal agents and on the diseases' characteristics and their life cycles in the environment. The importance of pathogenic Escherichia coli strains and emerging pathogens in drinking water-transmitted diseases is also briefly discussed. Microbiological water analysis is mainly based on the concept of fecal indicator bacteria. The main bacteria present in human and animal feces (focusing on their behavior in their hosts and in the environment) and the most important fecal indicator bacteria are presented and discussed (focusing on the advantages and limitations of their use as markers). Important sources of bacterial fecal pollution of environmental waters are also briefly indicated. In the last topic it is discussed which indicators of fecal pollution should be used in current drinking water microbiological analysis. It was concluded that safe drinking water for all is one of the major challenges of the 21st century and that microbiological control of drinking water should be the norm everywhere. Routine basic microbiological analysis of drinking water should be carried out by assaying the presence of Escherichia coli by culture methods. Whenever financial resources are available, fecal coliform determinations should be complemented with the quantification of enterococci. More studies are needed in order to check if ammonia is reliable for a preliminary screening for emergency fecal pollution outbreaks. Financial resources should be devoted to a better understanding of the ecology and behavior of human and animal fecal bacteria in environmental waters.
853 citations
TL;DR: Long-term management in Lake Taihu must consider both the human and climatic factors controlling these blooms and their impacts on water supply in this and other large lakes threatened by accelerating eutrophication.
Abstract: In late May, 2007, a drinking water crisis took place in Wuxi, Jiangsu Province, China, following a massive bloom of the toxin producing cyanobacteria Microcystis spp. in Lake Taihu, China’s third largest freshwater lake. Taihu was the city’s sole water supply, leaving approximately two million people without drinking water for at least a week. This cyanobacterial bloom event began two months earlier than previously documented for Microcystis blooms in Taihu. This was attributed to an unusually warm spring. The prevailing wind direction during this period caused the bloom to accumulate at the shoreline near the intake of the water plant. Water was diverted from the nearby Yangtze River in an effort to flush the lake of the bloom. However, this management action was counterproductive, because it produced a current which transported the bloom into the intake, exacerbating the drinking water contamination problem. The severity of this microcystin toxin containing bloom and the ensuing drinking water crisis were attributable to excessive nutrient enrichment; however, a multi-annual warming trend extended the bloom period and amplified its severity, and this was made worse by unanticipated negative impacts of water management. Long-term management must therefore consider both the human and climatic factors controlling these blooms and their impacts on water supply in this and other large lakes threatened by accelerating eutrophication.
761 citations
TL;DR: Despite a significant amount of research activity on the use of ANNs for prediction and forecasting of water resources variables in river systems, little of this is focused on methodological issues and there is still a need for the development of robust ANN model development approaches.
Abstract: Over the past 15 years, artificial neural networks (ANNs) have been used increasingly for prediction and forecasting in water resources and environmental engineering. However, despite this high level of research activity, methods for developing ANN models are not yet well established. In this paper, the steps in the development of ANN models are outlined and taxonomies of approaches are introduced for each of these steps. In order to obtain a snapshot of current practice, ANN development methods are assessed based on these taxonomies for 210 journal papers that were published from 1999 to 2007 and focus on the prediction of water resource variables in river systems. The results obtained indicate that the vast majority of studies focus on flow prediction, with very few applications to water quality. Methods used for determining model inputs, appropriate data subsets and the best model structure are generally obtained in an ad-hoc fashion and require further attention. Although multilayer perceptrons are still the most popular model architecture, other model architectures are also used extensively. In relation to model calibration, gradient based methods are used almost exclusively. In conclusion, despite a significant amount of research activity on the use of ANNs for prediction and forecasting of water resources variables in river systems, little of this is focused on methodological issues. Consequently, there is still a need for the development of robust ANN model development approaches.
730 citations
TL;DR: An overview of the recent research studies dealing with AOP methods for the removal of NOM and related compounds from drinking water is presented.
600 citations
TL;DR: An attempt has been made to understand the hydrogeochemical parameters to develop water quality index in Thirumanimuttar sub-basin and alkalis exceed alkaline earths, and strong acids exceed weak acid.
Abstract: An attempt has been made to understand the hydrogeochemical parameters to develop water quality index in Thirumanimuttar sub-basin. A total of 148 groundwater samples were collected and analyzed for major cations and anions. The domination of cations and anions was in the order of Na>Mg>Ca>K for cations and Cl>HCO(3) >SO(4) in anions. The hydrogeochemical facies indicate alkalis (Na and K) exceed alkaline earths (Ca and Mg) and strong acids (Cl and SO(4)) exceed weak acid (HCO(3)). Water quality index rating was calculated to quantify overall water quality for human consumption. The PRM samples exhibit poor quality in greater percentage when compared with POM due to effective leaching of ions, over exploitation of groundwater, direct discharge of effluents and agricultural impact. The overlay of WQI with chloride and EC correspond to the same locations indicating the poor quality of groundwater in the study area. SAR, Na%, and TH were noted higher during both the seasons indicating most of the groundwater locations not suitable for irrigation purposes.
521 citations
TL;DR: It is revealed that water eutrophication in most lakes was initiated in the 1980s when the national economy underwent rapid development and the problem is still serious, with frequent occurrence of damaging algal blooms, which have disrupted the normal supply of drinking water in shore cities.
Abstract: Lake water eutrophication has become one of the most important factors impeding sustainable economic development in China. Knowledge of the current status of lake water eutrophicatoin and determination of its mechanism are prerequisites to devising a sound solution to the problem. Based on reviewing the literature, this paper elaborates on the evolutional process and current state of shallow inland lake water eutrophication in China. The mechanism of lake water eutrophication is explored from nutrient sources. In light of the identified mechanism strategies are proposed to control and tackle lake water eutrophication. This review reveals that water eutrophication in most lakes was initiated in the 1980s when the national economy underwent rapid development. At present, the problem of water eutrophication is still serious, with frequent occurrence of damaging algal blooms, which have disrupted the normal supply of drinking water in shore cities. Each destructive bloom caused a direct economic loss valued at billions of yuan. Nonpoint pollution sources, namely, waste discharge from agricultural fields and nutrients released from floor deposits, are identified as the two major sources of nitrogen and phosphorus. Therefore, all control and rehabilitation measures of lake water eutrophication should target these nutrient sources. Biological measures are recommended to rehabilitate eutrophied lake waters and restore the lake ecosystem in order to bring the problem under control.
512 citations
TL;DR: In this article, the authors reviewed the fundamentals of agricultural irrigation using treated municipal wastewater and the status of municipal wastewater reuse in Greece and Spain with studies related to the effects on soils and plants.
464 citations
TL;DR: The HYPE model as discussed by the authors is a hydrological model for small-scale and large-scale assessments of water resources and water quality, developed at the Swedish Meteorological and Hydrological Institute during 2005-2007.
Abstract: The HYPE model is a hydrological model for small-scale and large-scale assessments of water resources and water quality, developed at the Swedish Meteorological and Hydrological Institute during 2005-2007. In the model, the landscape is divided into classes according to soil type, land use and altitude. In agricultural lands the soil is divided into three layers, each with individual computations of soil wetness and nutrient processes. The model simulates water flow and transport and turnover of nitrogen and phosphorus. Nutrients follow the same pathways as water in the model: surface runoff, macropore flow, tile drainage and outflow from individual soil layers. Rivers and lakes are described separately with routines for turnover of nutrients in each environment. Model parameters are global, or coupled to soil type or land use. The model was evaluated both by local calibrations to internal variables from different test basins and to data on discharge and nutrients from a large number of small basins. In addition, the estimated parameters were transferred to two larger basins in southern Sweden: River Ronnea and River Vindan. The resulting simulations were generally in good agreement with observations.
TL;DR: Water hyacinth (Eichhornia crassipes) is one of the world's most invasive aquatic plants and is known to cause significant ecological and socio-economic effects as discussed by the authors.
Abstract: Summary
1. Water hyacinth (Eichhornia crassipes) is one of the world’s most invasive aquatic plants and is known to cause significant ecological and socio-economic effects.
2. Water hyacinth can alter water clarity and decrease phytoplankton production, dissolved oxygen, nitrogen, phosphorous, heavy metals and concentrations of other contaminants.
3. The effects of water hyacinth on ecological communities appear to be largely nonlinear. Abundance and diversity of aquatic invertebrates generally increase in response to increased habitat heterogeneity and structural complexity provided by water hyacinth but decrease due to decreased phytoplankton (food) availability.
4. Effects of water hyacinth on fish are largely dependent on original community composition and food-web structure. A more diverse and abundant epiphytic invertebrate community may increase fish abundance and diversity, but a decrease in phytoplankton may decrease dissolved oxygen concentrations and planktivorous fish abundance, subsequently affecting higher trophic levels.
5. Little is known about the effects of water hyacinth on waterbird communities; however, increases in macroinvertebrate and fish abundance and diversity suggest a potentially positive interaction with waterbirds when water hyacinth is at moderate density.
6. The socio-economic effects of water hyacinth are dependent on the extent of the invasion, the uses of the impacted waterbody, control methods and the response to control efforts. Ecosystem-level research programmes that simultaneously monitor the effects of water hyacinth on multiple trophic-levels are needed to further our understanding of invasive species.
TL;DR: The role of vegetation in protecting streams from nonpoint source pollutants and in improving the quality of degraded stream water has been extensively studied as mentioned in this paper, with a focus on the role of riparian vegetation.
Abstract: We review the research literature and summarize the major processes by which riparian vegetation influences chemical water quality in streams, as well as how these processes vary among vegetation types, and discuss how these processes respond to removal and restoration of riparian vegetation and thereby determine the timing and level of response in stream water quality. Our emphasis is on the role that riparian vegetation plays in protecting streams from nonpoint source pollutants and in improving the quality of degraded stream water. Riparian vegetation influences stream water chemistry through diverse processes including direct chemi- cal uptake and indirect influences such as by supply of organic matter to soils and channels, modification of water movement, and stabilization of soil. Some processes are more strongly expressed under certain site condi- tions, such as denitrification where groundwater is shallow, and by certain kinds of vegetation, such as channel stabilization by large wood and nutrient uptake by faster-growing species. Whether stream chemistry can be managed effectively through deliberate selection and management of vegetation type, however, remains uncer- tain because few studies have been conducted on broad suites of processes that may include compensating or reinforcing interactions. Scant research has focused directly on the response of stream water chemistry to the loss of riparian vegetation or its restoration. Our analysis suggests that the level and time frame of a response to restoration depends strongly on the degree and time frame of vegetation loss. Legacy effects of past vegetation can continue to influence water quality for many years or decades and control the potential level and timing of water quality improvement after vegetation is restored. Through the collective action of many processes, vegeta- tion exerts substantial influence over the well-documented effect that riparian zones have on stream water qual- ity. However, the degree to which stream water quality can be managed through the management of riparian vegetation remains to be clarified. An understanding of the underlying processes is important for effectively using vegetation condition as an indicator of water quality protection and for accurately gauging prospects for water quality improvement through restoration of permanent vegetation. (KEY TERMS: assessment; biogeochemistry; buffers; legacy effects; nonpoint source pollution; resilience; resto- ration; rivers ⁄streams; soils; watershed management.)
TL;DR: Models predict that on the 22.8% of GBR reefs where guideline values are currently exceeded, water quality improvement should reduce macroalgal cover and increase the richness of hard corals and phototrophic octocorals on average by 16% and 33%, respectively (all else being equal).
Abstract: Degradation of inshore coral reefs due to poor water quality is a major issue, yet it has proved difficult to demonstrate this linkage at other than local scales. This study modeled the relationships between large-scale data on water clarity and chlorophyll and four measures of reef status along the whole Great Barrier Reef, Australia (GBR; 12–24° S). Four biotic groups with different trophic requirements, namely, the cover of macroalgae and the taxonomic richness of hard corals and phototrophic and heterotrophic octocorals, were predicted from water quality and spatial location. Water clarity and chlorophyll showed strong spatial patterns, with water clarity increasing more than threefold from inshore to offshore waters and chlorophyll decreasing approximately twofold from inshore to offshore and approximately twofold from south to north. Richness of hard corals and phototrophic octocorals declined with increasing turbidity and chlorophyll, whereas macroalgae and the richness of heterotrophic octocorals ...
TL;DR: In this article, water samples were collected from twelve different locations along the course of the river and its tributaries on summer and the winter seasons and the concentrations of trace metals such as cadmium, cromium, copper, cobalt, iron, manganese, nickel, lead, mercury and zinc were determined using atomic absorption spectrophotometer.
Abstract: The objective of the study is to reveal the seasonal variations in the river water quality with respect to heavy metals contamination. To get the extend of trace metals contamination, water samples were collected from twelve different locations along the course of the river and its tributaries on summer and the winter seasons. The concentrations of trace metals such as cadmium, cromium, copper, cobalt, iron, manganese, nickel, lead, mercury and zinc were determined using atomic absorption spectrophotometer. Most of the samples were found within limit of Indian drinking water standard (IS: 10500). The data generated were used to calculate the heavy metal pollution index of river water. The mean values of HPI were 36.19 in summer and 32.37 for winter seasons and these values are well below the critical index limit of 100 because of the sufficient flow in river system. Mercury and chromium could not be traced in any of the samples in the study area.
TL;DR: High performance liquid chromatography coupled to a diode array detector method was developed to detect disperse dyes in water samples over the range 0.50-35 ng, with detection limits of 0.09 ng, 0.84 ng and 0.08 ng, respectively, with good repeatability and accuracy, that are contributing to the mutagenicity found in the Cristais River, São Paulo, Brazil.
TL;DR: Assessment of trace metals in surface water samples would help establish pollutant loading reduction goal and the total maximum daily loads, and consequently contribute to preserve public health in the Han River basin and develop water conservation strategy for the interbasin water transfer project.
TL;DR: In this article, the authors calculated spatially explicit fertilizer inputs of nitrogen (N) and phosphorus (P) by fusing national-level statistics on fertilizer use with global maps of harvested area for 175 crops.
Abstract: Agriculture has had a tremendous impact on soil nutrients around the world. In some regions, soil nutrients are depleted because of low initial soil fertility or excessive nutrient removals through intense land use relative to nutrient additions. In other regions, application of chemical fertilizers and manure has led to an accumulation of nutrients and subsequent water quality problems. Understanding the current level and spatial patterns of fertilizer and manure inputs would greatly improve the ability to identify areas that might be sensitive to aquatic eutrophication or to nutrient depletion. The authors calculated spatially explicit fertilizer inputs of nitrogen (N) and phosphorus (P) by fusing national-level statistics on fertilizer use with global maps of harvested area for 175 crops. They also calculated spatially explicit manure inputs of N and P by fusing global maps of animal density and international data on manure production and nutrient content. Significantly higher application rate...
TL;DR: The results show that for the majority of compounds a substantial margin of safety exists between the maximum concentration in surface water, groundwater and/or drinking water and the (provisional) guideline value.
TL;DR: In this paper, the authors discuss some of the main variables involved in public perception of drinking water quality, including risk perception, attitudes towards water chemicals, contextual cues provided by the supply system, familiarity with specific water properties, trust in suppliers, past problems attributed to water quality and information provided by media and interpersonal sources.
TL;DR: Contamination of heavy metals, namely, lead, cadmium, zinc, nickel, copper, chromium and mercury was evaluated in the samples of water and tissues of Labeo rohita and Ctenopharyngodon idella of Upper Lake of Bhopal during summer, rainy and winter seasons of 2005–2006.
Abstract: Contamination of heavy metals, namely, lead, cadmium, zinc, nickel, copper, chromium and mercury was evaluated in the samples of water and tissues of Labeo rohita and Ctenopharyngodon idella of Upper Lake of Bhopal collected during summer, rainy and winter seasons of 2005-2006. Different organs of the fishes accumulated varying quantities of different heavy metals. In L. rohita, accumulation of heavy metals was in the sequence liver>kidney>gills>muscles, and in C. idella, it was gills>liver>kidney>muscles. Zn was the highest accumulating metal in fish, whilst Hg was the lowest and was well corroborated with those of water. The values of heavy metals were so far well within the maximum permissible standard value of heavy metals for drinking water and for fish culture as prescribed by various national and international agencies.
TL;DR: Results from these case studies suggest that spatially variable patterns of snow or summer precipitation associated with regional climate change across NE Asia will have significant impacts on watershed biogeochemical processes and surface water quality, in interactions with local topography, land use change, or acid deposition.
TL;DR: The pesticides belong to a category of chemicals used worldwide as herbicides, insecticides, fungicides, ro-denticides, molluscicides, nematicides, and plant growth regulators in order to control weeds, pests and dis-eases in crops as well as for health care of humans and animals.
Abstract: The pesticides belong to a category of chemicals used worldwide as herbicides, insecticides, fungicides, ro-denticides, molluscicides, nematicides, and plant growth regulators in order to control weeds, pests and dis-eases in crops as well as for health care of humans and animals. The positive aspect of application of pesti-cides renders enhanced crop/food productivity and drastic reduction of vector-borne diseases. However, their unregulated and indiscriminate applications have raised serious concerns about the entire environment in general and the health of humans, birds and animals in particular. Despite ban on application of some of the environmentally persistent and least biodegradable pesticides (like organochlorines) in many countries, their use is ever on rise. Pesticides cause serious health hazards to living systems because of their rapid fat solu-bility and bioaccumulation in non-target organisms. Even at low concentration, pesticides may exert several adverse effects, which could be monitored at biochemical, molecular or behavioral levels. The factors af-fecting water pollution with pesticides and their residues include drainage, rainfall, microbial activity, soil temperature, treatment surface, application rate as well as the solubility, mobility and half life of pesticides. In India organochlorine insecticides such as DDT and HCH constitute more than 70% of the pesticides used at present. Reports from Delhi, Bhopal and other cities and some rural areas have indicated presence of sig-nificant level of pesticides in fresh water systems as well as bottled drinking mineral water samples. The ef-fects of pesticides pollution in riverine systems and drinking water in India has been discussed in this review.
TL;DR: Water analyses from the four principal geomorphological regions of Bangladesh showed that hand tubewells of the Tableland and Hill tract regions are primarily free from As contamination, while the Flood plain and Deltaic region, including the Coastal region, are highly As-contaminated.
TL;DR: Results of electrical conductivity and chloride express large variation between minimum and maximum values and high standard deviation, which suggests that the water chemistry in the study region is not homogeneous and influenced by complex contamination sources and geochemical process.
Abstract: Hydrogeochemical investigations were carried out in Chithar River basin, Tamil Nadu, India to identify the major geochemical processes that regulate groundwater chemistry. For this study, long-term (1991-1997) and recent water quality data (2001-2002) for 30 groundwater wells spread over the study area were used to understand the groundwater geochemistry and hydrogeochemical process regulating groundwater quality. Groundwater quality data obtained from more than 400 water samples were employed. Results of electrical conductivity and chloride express large variation between minimum and maximum values and high standard deviation, which suggests that the water chemistry in the study region is not homogeneous and influenced by complex contamination sources and geochemical process. Nitrate and depth to water table expose the influences of surface contamination sources, whereas dissolved silica, fluoride and alkalinity strongly suggest the effect of rock-water interaction. In the study region, weathering of carbonate and silicate minerals and ion exchange reactions predominantly regulate major ion chemistry. Besides, the concentrations of sulphate, chloride and nitrate firmly suggest the impact of agricultural activities such as irrigation return flow, fertiliser application, etc on water chemistry in the study region.
TL;DR: Most water quality variables were influenced primarily by pollution due to industrial wastewater, agricultural activities and urban runoff, and mixed source pollution dominated in LP, MP, and HP.
TL;DR: This study showed that water stagnation in household pipes results in considerable microbial changes and emphasizes the need for the development of good material validation methods, recommendations and spot tests for in-house water installations.
06 May 2010
TL;DR: In this article, the authors present the context for selenium risk assessment in the context of a global problem, which they call Selenium risk assessment (SRL) problem.
Abstract: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Background and Need for Workshop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 Workshop Purpose and Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Participation and Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Workgroup Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Workgroup 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Problem formulation: Context for selenium risk assessment . . . . . . . . . . . . . . . . . . . . . 9 Selenium is a global problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Case studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Conceptual model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 How to investigate a potential selenium problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Recommendations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Workgroup 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Environmental partitioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Workgroup 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Bioaccumulation and trophic transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Workgroup 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Selenium toxicity to aquatic organisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Workgroup 5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Risk characterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Importance of problem formulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Risk characterization: Unique challenges concerning selenium . . . . . . . . . . . . . . . . . . 26 Risk management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 Uncertainties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Overall Workshop Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 Appendix: SETAC Pellston Workshop Participants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 List of Figures Figure 1 Conceptual model depicting Se dynamics and transfer in aquatic ecosystems . . . . . . . . . . . . .11 Figure 2 Hierarchy of effects across levels of biological organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 Figure 3 Potential sources of Se to aquatic systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 Figure 4 Selenium species associated with major processes in aquatic systems . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Figure 5 Partitioning of Se among environmental compartments in a typical aquatic system. . . .16 Figure 6 Selenium enrichment and trophic transfer in aquatic food webs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19 Figure 7 Selenium accumulation in different species of algae, invertebrates, and fish . . . . . . . . . . . . . . . .20 Figure 8 Conceptual pathway of Se transfer in aquatic ecosystems and relative certainty with which Se concentrations in environmental compartments can be assessed in making accurate characterizations of risk . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28 List of Tables Table 1 Assessment endpoints and measures of exposure and effect for aquatic and aquaticlinked organisms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 Table 2 Uncertainties and recommendations for future research pertaining to toxicity of Se species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 Ecological Assessment of Selenium in the Aquatic Environment 4
TL;DR: Exposure to the three compounds from drinking water is unlikely to pose a health risk, according to this study.