Source Water Characteristics Research Articles

Icings as sentinels and modifiers of water flow through winter landscapes: An exploration of physico‐chemical processes on the lake‐dominated, discontinuous permafrost Taiga Shield

AbstractThe winter hydrological period is in transition across the Canadian subarctic, as climate warming is shifting precipitation regimes, thawing permafrost, and altering active layer dynamics, and thus increasing the overall amount, and variability, of winter streamflow. Effects of these changes are poorly understood on the Taiga Shield, which comprises ~20% of North America's permafrost‐covered area, and is characterized by a unique ‘fill‐and‐spill’ hydrology whereby runoff generation requires the exceedance of lake basin storage thresholds. Here, we assessed lake hydrostatic levels and used trail camera images of icings, which are sheet‐like masses of layered ice that are common manifestations of wintertime flow on the Taiga Shield, to understand landscape controls on winter water movement in this region. We further used paired geochemical measurements to explore how source water characteristics affect icing chemistry, and the degree to which icings may modify the chemical composition of active winter flow. We undertake this work over 2 years, and across watersheds of different sizes and lake basin characteristics. We show that icing growth is driven by hydroclimatic controls that include fill‐and‐spill hydrologic constraints and winter air temperatures, and that pre‐freshet pulses of water flow are common within this landscape. Across winters with variable antecedent precipitation levels, a larger catchment was able to support icing growth via continued runoff generation, while small catchments were not. Icings were often chemically dilute compared with source waters, indicating that solute exclusion may actively enrich geochemical concentrations in flowing water. Across icings, chemical variation appeared related to source water type (groundwater versus lake; lake size) and apparent redox conditions. These results highlight that streamwater hydrology and biogeochemistry can be dynamic during the understudied winter period, and illustrate that icings may alter the composition of wintertime flow as it moves through fluvial networks.

From laboratory to pilot-scale: Assessing dissolved organic matter, biological stability and per- and polyfluoroalkyl substances removal on managed aquifer recharge performance

Managed aquifer recharge (MAR) is a promising technique for enhancing groundwater resources and addressing water scarcity. Particularly, this research highlights the novelty and urgent need for MAR facilities in the Chungcheongnam-do region of South Korea as a solution to augment groundwater resources and combat water scarcity. This research encompasses a comprehensive assessment, ranging from laboratory-scale column experiments to pilot-scale tests, focusing on dissolved organic matter (DOM) characterization, natural organic matter (NOM) removal, and water quality improvement, including biological stability. In the laboratory, DOM characteristics of source water and recharged groundwater were analyzed using advanced dissolved organic characteristic tools, and their potential impacts on water quality, as well as per- and polyfluoroalkyl substances (PFASs) were assessed. DOM, total cell counts, and several PFASs with molecular weights >450 Da (particularly long-chain PFASs showing >99.9 % reduction) were effectively reduced in a laboratory-scale experiment. A laboratory-scale column study revealed that most selected PFASs were not effectively removed. Moving to the pilot-scale, a series of experiments were conducted to assess NOM removal during soil passage. Similar to the results of the laboratory-scale experiment, MAR demonstrated significant potential for reducing NOM concentrations, thus improving water quality. Regarding biological stability, assimilable organic carbon in production well (i.e., final produced water by MAR process) was lower than both two sources of surface water (e.g., SW1 and SW2). This suggests that water derived from PW (i.e., production well) exhibited biological stability, undergoing effective biodegradation by aerobic bacteria during soil passage. The findings from this study highlight the critical importance of implementing MAR techniques in regions facing water scarcity, emphasizing its potential to significantly enhance future water security initiatives.

Living with technological drought: Experience of smallholding farmers of Bangladesh

Technological drought is caused by a lack of irrigation technology and a poor water management system. Here we present and analyse the results of a large survey of farmers in Bangladesh, designed to reveal their experience of and attitudes to, as well as factors and challenges of technological drought management. Also, we analysed the impact of water sources and the role of irrigation development to mitigate the technological drought taking North Bengal of Bangladesh as a case study. To explore the nature and characteristics of technological drought, we have used both qualitative and quantitative data from the study area. We used Principal Component Analysis (PCA) to find out the underlying dimensions and factor loadings of the technological drought using the field data. Moreover, we compared the relations and associations between socio-demographic, water source characteristics and technological drought perceptions. PCA results indicated seven underlying dimensions (challenges) out of thirty-one factors of technological drought related to river water management, irrigation technology, socio-economic conditions, land use, and electricity and fuel supply. The high population, lack of modern irrigation technology, upstream management problems, inefficiencies in the system, electricity connections, load shedding, and poor socio-economic conditions prevent people from getting the water they desperately need in the case study area. We also found a significant relationship between farmers’ socio-demographic and water source characteristics with technological drought perceptions. Although there has been increasing use of irrigation technology and improved water resource management in recent years, it is essential to highlight that there will likely be more challenges in the future if this trend continues.

Assessing the Health Impact of Disinfection Byproducts in Drinking Water.

This study provides a comprehensive investigation of the impact of disinfection byproducts (DBPs) on human health, with a particular focus on DBPs present in chlorinated drinking water, concentrating on three primary DBP categories (aliphatic, alicyclic, and aromatic). Additionally, it explores pivotal factors influencing DBP formation, encompassing disinfectant types, water source characteristics, and environmental conditions, such as the presence of natural materials in water. The main objective is to discern the most hazardous DBPs, considering criteria such as regulation standards, potential health impacts, and chemical diversity. It provides a catalog of 63 key DBPs alongside their corresponding parameters. From this set, 28 compounds are meticulously chosen for in-depth analysis based on the above criteria. The findings strive to guide the advancement of water treatment technologies and intelligent sensory systems for the efficient water quality surveillance. This, in turn, enables reliable DBP detection within water distribution networks. By enriching the understanding of DBP-associated health hazards and offering valuable insights, this research is aimed to contribute to influencing policy-making in regulations and treatment strategies, thereby protecting public health and improving safety related to chlorinated drinking water quality.

A hybrid process combining ion exchange resin and bipolar membrane electrodialysis for reverse osmosis remineralization

A new reverse osmosis (RO) permeate remineralization process combining ion exchange resin and bipolar membrane electrodialysis (BMED) was developed. Its feasibility for hardness ions recovery and RO permeate remineralization was investigated. The effect of several operation conditions on the efficiency of the combined remineralization process was studied. Highly efficient cation exchange resin loading was achieved at a low flow rate and low feed solution concentration. The recovered calcium purity and yield considerably improved under gradient elution methods in comparison with commonly applied conventional isocratic elution methods using the same eluent quantity. The purity of the produced acid and base using BMED dropped noticeably with increasing feed NaCl concentration, presumably related to decreased permselectivity of the ion-exchange membranes. The drop in the purity of the calcium recovered when eluting the cation exchange resin with BMED-produced HCl in comparison with commercially available acid at 50 % yield was shown not to affect the remineralization process, where a dilution factor could be applied. This study confirmed the technical feasibility of the developed process for RO permeate remineralization. However, its application can be limited by the water source characteristics, the energy-intensive bipolar membrane process, and applied operational conditions, where more investigation is still needed.

Factors affecting particle-microorganism association and UV disinfection: Effect of source water, organics, and particle characteristics

Ultraviolet (UV) disinfection is usually applied following filtration to reduce particulate concentrations and improve disinfection effectiveness. However, there is a desire to avoid costs associated with pre-treatment for small and resource-limited treatment facilities. Lack of pre-treatment can increase the degree of particle-microorganism association and inhibit disinfection by UV. As such, there is a need to quantify the degree to which unfiltered water conditions may decrease UV performance. In this study, a range of water quality was produced at bench scale to simulate extreme water conditions. Overall, particle type primarily impacted UV disinfection, particularly at lower turbidity (<5 NTU). The composition of turbidity-causing material was reported as the controlling factor in particle-microorganisms association and disinfection achieved by UV. In particular, it was observed that the surface charge of particulates governs the proportion of microorganisms associated with particles and the resulting loss of disinfection efficiency. Multiple linear regression analysis of UV disinfection results showed incorporating zeta potential in conjunction with commonly used indicators increased the accuracy of predicting UV disinfection achieved. The results of this study highlight some of the risks of UV disinfection of unfiltered supplies and can be used to optimize UV disinfection in small-scale or resource-limited water treatment plants.

Trihalomethanes and physicochemical quality of drinking water in Addis Ababa, Ethiopia

BackgroundTrihalomethanes (THMs) are the most dominant fraction of all the byproducts formed during chlorination of water. Disinfection by product (DBP) formation in water is a function of numerous factors, including pH, temperature, residual chlorine, source water characteristics, and organic matter. No study has determined the THM level in the drinking water supply of Addis Ababa, Ethiopia. MethodsA cross-sectional design was conducted to collect water samples in the water supply distribution networks of Addis Ababa, Ethiopia. Twenty-one (21) sampling stations yielded a total of one hundred twenty (120) samples of drinking water. The sample handling and collection procedures were carried out in accordance with USEPA guidelines. A DB-5 capillary column was used to separate the THMs, which were detected using GC-ECD (gas chromatography-electron capture detector). Spectrophotometric and in situ methods were used for physicochemical parameters. Redundancy analysis (RDA) was used for data analysis of trihalomethanes and environmental variables using CANOCO 4.5. ResultsThe mean concentration of total trihalomethanes in drinking water in Addis Ababa was 76.3 μg/L. The concentration of chloroform in the drinking water supply in Addis Ababa, Ethiopia, ranged between 4.03 and 79.4 μg/L. The mean total THMs in the Legedadi and Gefersa water supply systems were 77.4 μg/L and 69.66 μg/L, respectively. The residual chlorine, phosphates, UV absorbance at 254 nm, and combined chlorine had positive correlations with THM formation. However, electron conductivity had a negative correlation with THM formation. ConclusionsChloroform contributed the most to TTHMs in nearly all samples. The residual chlorine, UV absorbance, phosphate and hardness as calcium, and electron conductivity were found to be the main predictors determining the abundance and distribution of trihalomethanes. The monitoring and regulation of the THMs is required on a regular basis to analyse trends and guide the water treatment and distribution system.

The complex nature of household water supply: an evidence-based assessment of urban water access in Southwest Nigeria

Abstract Access to domestic water supply is a big challenge for many households in developing countries, as a large number of households do not have access to municipal water sources. The purpose of this study is to investigate the nature of access and characteristics of water sources and their impact on the choice and usage of water by providing empirical and statistical evidence. A survey of 1,300 households was conducted across six major cities in Southwest Nigeria, using structured questionnaires, field surveys, personal interviews, and observations. The data obtained were analysed using SPSS 27 for descriptive statistics and characterised using enhancement-based strategies. The result showed that 5% of respondents had access to pipe water, 66% used private wells and boreholes, and 29% used off-site water sources. The study discovered that 15 different water sources with unique attributes were consumed. The daily consumption ranged between 301 and 361 and 1,153 and 1,421 litres per household (L/hh/d) for those using off-site and on-site water sources, respectively. This study provides new insights with empirical evidence. As such, there is a need to re-evaluate the present water supply policy implementation, funding approach, and level of coverage. Additional policies that support and fund decentralised water projects, without compromising on water quality, should be provided, since they are more accessible to the people.

Association of park drinking water source characteristics and water intake in San Francisco Bay Area parks

Abstract Over half of U.S. adults visit parks regularly. Thus, it is important to understand how park drinking water sources affect visitors’ water consumption. In this cross-sectional study of 30 San Francisco Bay Area parks, 4 day-long direct observations of visitors’ drinking water and other beverages were conducted, along with audits of sugar-sweetened beverage access and drinking water source conditions, including flow, appeal, and obstructions. Outcomes were log-transformed to account for skewness, and results were analyzed using mixed-effects regression models to account for matching and clustering by park and observation day. A greater proportion of water sources in low-income parks were unappealing (57.14 vs. 25.00%, P = 0.01) or in a poor condition (69.70 vs. 43.24%, P = 0.03). A lower proportion of visitors drank water from park fountains that were unappealing (−31%), had poor flow (−22%), or had obstructions (−58%) than those without these conditions. Although only obstructions to the source and water intake were significantly related after adjustment, we observed important effects on water intake by water source appeal and flow. As park water source conditions contribute to water intake, cities should consider installing appealing, functional, and easy to access water sources in parks, particularly those in lower-income neighborhoods.

A critical review on operation and performance of source water control strategies for cyanobacterial blooms: Part I-chemical control methods

Cyanobacterial blooms produce nuisance metabolites (e.g., cyanotoxins and T&O compounds) thereby posing water quality management issues for aquatic sources used for potable water production, aquaculture, and recreation. A variety of in-lake/reservoir control measures are implemented to reduce the abundance of nuisance cyanobacteria biomass or decrease the amount of available phosphorous (P). This paper critically reviews the chemical control strategies implemented for in-lake/reservoir management of cyanobacterial blooms, i.e., algaecides and nutrient sequestering coagulants/flocculants, by highlighting (i) their mode of action, (ii) cases of successful and unsuccessful treatment, (iii) and factors influencing performance (e.g., water quality, process control techniques, source water characteristics, etc.). Algaecides generally result in immediate improvements in water quality and offer selective cyanobacterial control when peroxide-based alagecides are used. However, they have a range of limitations: causing cell lysis and release of cyanotoxins, posing negative impacts on aquatic plants and animals, leaving behind environmentally relevant treatment residuals (e.g., Cu in water and sediments), and offering only short-term bloom control characterized by cyanobacterial rebound. Coagulants/flocculants (alum, iron, calcium, and lanthanum bentonite) offer long-term internal nutrient control when external nutrient loading is controlled. Treatment performance is often influenced by background water quality conditions, and source water characteristics (e.g., surface area, depth, mixing regimes, and residence time). The reviewed case studies highlight that external nutrient load reduction is the most fundamental aspect of cyanobacterial control. None of the reviewed control strategies provide a comprehensive solution to cyanobacterial blooms.

Improving Water Supply Capacity of Drainage Systems at Humid Areas in the Changing Climate

Abstract The paper focuses on research on improving the water supply of drainage systems of humid areas in the context of climate change. The aim of the research is to elaborate on the ways for increasing the available water supply of drainage systems and restoring active water regulation on reclaimed lands in a changing climate. The paper presents the results of the research on improving the available water supply of drainage systems in the humid zone of Ukraine in a changing climate. It was specified in the face of increasing water scarcity providing the optimal water regime regulation on drained lands is possible due to the increase in the available water supply of drainage systems. It can be achieved thanks to the accumulating capacity of reclaimed areas, namely usage of free soil capacity of the aeration zone and open canals, accumulation of water reserve volumes in storage tanks due to the accumulation of surface and drainage runoff. Taking into account the design features of different types of drainage systems, existing water management technologies, characteristics of water sources and their close proximity to the drainage systems, the technological schemes of water intake from rivers and reservoirs, and its supply to the drained areas for irrigation needs were developed. In a face of increasing water scarcity, it is also expedient to apply resource-saving technologies to control the available water supply for crops.

Removal of disinfection by-product precursors by Al-based coagulants: A comparative study on coagulation performance

Coagulation is well-established for controlling regulated disinfection by-products (DBPs), but its effectiveness for controlling unregulated DBPs remains unclear. The efficiency of coagulation in controlling unregulated DBPs requires clarification owing to their relatively high toxicity. In this study, three Al-based coagulants, aluminum sulfate (Alum), polyaluminum chloride (PAC), and a novel type of covalently bond hybrid coagulant (CBC, synthesized using AlCl3) were selected, and the coagulation performance of these Al-based coagulants in controlling DBPs and DBP-associated toxicity was compared over 5 classes of DBPs, including trihalomethanes, haloacetic acids, haloacetaldehydes, haloacetonitriles, and halonitromethanes. The results showed that Alum was the least efficient in removing DBP precursors among the three coagulants. The effectiveness of CBC and PAC for DBP control varied with the characteristics of source waters. CBC had an advantage in water with a low content of humic acids, and reduced DBP concentration and DBP-associated toxicity by 47% and 25%, respectively. For water rich in aromatic organics, CBC might serve as DBP precursors at a high-required dosage, suggesting that a trade-off between enhanced DBP control and serving as DBP precursors should be considered for CBC coagulation; PAC achieved the most reduction in DBP concentration and DBP-associated toxicity by 50% and 34%, respectively.

Modeling Bacterial Regrowth and Trihalomethane Formation in Water Distribution Systems

The formation of bacterial regrowth and disinfection by-products is ubiquitous in chlorinated water distribution systems (WDSs) operated with organic loads. A generic, easy-to-use mechanistic model describing the fundamental processes governing the interrelationship between chlorine, total organic carbon (TOC), and bacteria to analyze the spatiotemporal water quality variations in WDSs was developed using EPANET-MSX. The representation of multispecies reactions was simplified to minimize the interdependent model parameters. The physicochemical/biological processes that cannot be experimentally determined were neglected. The effects of source water characteristics and water residence time on controlling bacterial regrowth and Trihalomethane (THM) formation in two well-tested systems under chlorinated and non-chlorinated conditions were analyzed by applying the model. The results established that a 100% increase in the free chlorine concentration and a 50% reduction in the TOC at the source effectuated a 5.87 log scale decrement in the bacteriological activity at the expense of a 60% increase in THM formation. The sensitivity study showed the impact of the operating conditions and the network characteristics in determining parameter sensitivities to model outputs. The maximum specific growth rate constant for bulk phase bacteria was found to be the most sensitive parameter to the predicted bacterial regrowth.

A year-long cyclic pattern of dissolved organic matter in the tap water of a metropolitan city revealed by fluorescence spectroscopy

Delivering drinking water with stable quality in metropolitan cities is a big challenge. This study investigated the year-long dynamics of dissolved organic matter (DOM) in the tap water and source water of a metropolitan city in southern China using fluorescence spectroscopy. The DOM detected in the tap water, and source water of Shenzhen city was season and location-dependent. A year-long cyclic trend of DOM was found with predominate protein-like fluorescence in the dry season compared to the humic-like enriched DOM in the wet season. A general DOM pattern was estimated by measuring the shift in dominant fluorescence regions on the excitation-emission matrix (EEM). The difference in fluorescent DOM (FDOM) composition (in terms of the ratio of protein-like to humic-like fluorescence) was above 200% between wet and dry seasons. The taps associated with reservoirs receiving water from the eastern tributary of Dongjiang River showed significant changes in protein-like contents than the taps with source water originating from the western part of the river. This study highlights the importance of optimizing drinking water treatment plants' operational conditions after considering seasonal changes and source water characteristics.

Environmental isotope characteristics of water sources in the Sokoto Basin – an evaluation of the role of meteoric recharge and residence time

ABSTRACT The water sources of the Sokoto Basin are mainly of interrelated origin. The groundwater is composed of old water recharged in different climate regimes and of recent meteoric water. The recharge source is influenced by both local and regional moisture circulation given the lower slope and intercept of the local meteoric water line (LMWL) relative to those of the global meteoric water line (GMWL) and distribution of the deuterium excess d from –20 to +14 ‰. The identified interrelated water sources were confirmed by variations in tritium measured between 4.9 and <0.4 TU. The groundwater and surface water were identified to be of mixed origin, consisting of interrelated and recent types. This depicts active recharge taking place across the basin. The groundwater recharge was established to be renewable; however, rational water exploitation should be exercised considering growing water demand with the corresponding population rise.

Late Quaternary deep and surface water mass evolution in the northeastern Indian Ocean inferred from carbon and oxygen isotopes of benthic and planktonic foraminifera

New planktonic and benthic foraminiferal stable isotope records from core YDY05 (northeastern Indian Ocean) provide new insights into paleoceanographic changes in the northeastern Indian Ocean since the last glacial period. The distinct δ18O decrease was observed since the beginning of the deglaciation to the mid-Holocene (∼8–6 kyr BP), possibly reflecting a reduction in surface salinity in the central Bay of Bengal (BoB) water, which probably resulted from strengthened precipitation, concurrent enhanced river discharge and rising sea-level, related to the intensification of Indian Summer Monsoon (ISM). Variations in benthic δ13C and δ13CPlanktonic-Benthic in our core site reflect significant variations in source water characteristics over the LGM-Holocene. The large δ13CPlanktonic-Benthic offset during the glacial period suggests a more sluggish deep water circulation, and lower δ13CPlanktonic-Benthic from the deglaciation to the Holocene suggests an enhanced deep water circulation in the central BoB. The drastic depletion in benthic δ13C during the glacial period suggests a significant reduction of North Atlantic Deep Water (NADW) intrusion and a progressive influx of Antarctic Bottom Water (AABW) and 12C-rich Circumpolar Deep Water (CDW) into the central BoB. In contrast, since the deglaciation, the central BoB experienced a drastically increased intrusion of better ventilated and 13C-rich NADW. The differences in benthic δ18O between the LGM section and the Holocene exceeds the ice volume effect by ∼0.5‰, providing further evidence that the deep water mass of the central BoB was influenced by the less dense NADW, instead of the AABW, since the last deglaciation.

Characteristics of packaged water production facilities in Greater Accra, Ghana: implications for water safety and associated environmental impacts

Abstract Packaged water (sold in bags or bottles) is widely consumed in many countries and is the main drinking-water source for most urban Ghanaian households. There are, however, few studies of packaged water production. This study aims to assess the source water, treatment, and manufacturing characteristics of sachet water (vended in 500 mL plastic bags), together with point-of-manufacture risks to hygienic production. A sample of 90 sachets was collected of brands sold in four neighbourhoods in Accra, Ghana, their packaging and physical characteristics recorded, and a risk score calculated from these. Production processes were observed at 60 associated sachet factories, producers interviewed, and surrounding neighbourhoods surveyed for contamination hazards. 80% of producers packaged groundwater from boreholes and all treated water via reverse osmosis. Almost all manufacturers (95%) reported site visits by regulators in the previous year and few risks to hygienic production were observed at factories. Sanitary risk scores were 9.2% higher at the seven factories never visited by a regulator, though this difference was not significant (t = 1.81; p = 0.07). This survey suggests most Ghanaian sachet water originates from groundwater and is comparatively safe, though a minority remains unregulated. Groundwater governance policy could support this industry in meeting Greater Accra's growing water demand through the designation of protected municipal wellfields.

Source Water Characteristics and Building-specific Factors Influence Corrosion and Point of Use Water Quality in a Decentralized Arctic Drinking Water System.

Access to clean and safe drinking water is a perpetual concern in Arctic communities because of challenging climatic conditions, limited options for the transportation of equipment and process chemicals, and the ongoing effects of colonialism. Water samples were gathered from multiple locations in a decentralized trucked drinking water system in Nunavut, Canada, over the course of one year. The results indicate that point of use drinking water quality was impacted by conditions in the source water and in individual buildings and strongly suggest that lead and copper measured at the tap were related to corrosion of onsite premise plumbing components. Humic-like substances were the dominant organic fraction in all samples, as determined by regional integration of fluorescence data. Iron and manganese levels in the source water and throughout the water system were higher in the winter and lower in the summer months. Elevated concentrations of copper (>2000 μg L-1) and lead (>5 μg L-1) were detected in tap water from some buildings. Field flow fractionation coupled with inductively coupled plasma mass spectrometry and ultraviolet-visible spectrometry was used to demonstrate the link between source water characteristics (high organics, iron and manganese) and lead and copper in point of use drinking water.

Constructed floating wetland with mooring system technology to improve water quality in Gedebage Reservoir, Bandung

Gedebage Reservoir is built as retention ponds, in the future it will be developed into an integrated religious tourism area, so that the quality of water reservoir must suitable for tourism. Constructed floating wetland with mooring system, besides being used as water quality improvement technology, it will also add aesthetic value. The purpose of this study was to identify the possibility of applying the constructed floating wetland in the Gedebage Reservoir area. This study uses secondary data to determine the design parameters and characteristics of water sources, design parameters are used for location recommendations, while the characteristics of water sources are to determine the accuracy of the technology used. The result shows that the placement of a floating wetland technology with mooring system in Gedebage reservoir has meets the requirements of design parameters than in a biological filter channel. The characteristics of the Gedebage Reservoir water source that have not met requirements consist of several parameters, namely: Ammonia, Chlorine, Mn, DO, Sulfide, Detergent, Oil and Fat, Cd, Pb, DO, BOD, COD, Fecal Coliform and Total Coliform. Whereas, based on the ratio of BOD5 / COD in the dry season that ranged from 0.25 indicating that the water had been toxin, so that it would disrupt the development of biofilms, so in addition to wetland, a pre-treatment was needed before entering the reservoir.

Integrated Assessment of Wastewater Reuse, Exposure Risk, and Fish Endocrine Disruption in the Shenandoah River Watershed.

Reuse of municipal and industrial wastewater treatment plant (WWTP) effluent is used to augment freshwater suppliesglobally. The Shenandoah River Watershed (U.S.A.) was selected to conduct on-site exposure experiments to assess endocrine disrupting characteristics of different source waters. This investigation integrates WWTP wastewater reuse modeling, hydrological and chemical characterization, and in vivo endocrine disruption bioassessment to assess contaminant sources, exposure pathways, and biological effects. The percentage of accumulated WWTP effluent in each river reach (ACCWW%) was used to predict environmental concentrations for consumer product chemicals (boron), pharmaceutical compounds (carbamazepine), and steroidal estrogens (estrone, 17-β-estradiol, estriol, and 17-α-ethinylestradiol). Fish endocrine disruption was evaluated using vitellogenin induction in adult male or larval fathead minnows. Water samples were analyzed for >500 inorganic and organic constituents to characterize the complex contaminant mixtures. Municipal ACCWW% at drinking water treatment plant surface water intakes ranged from <0.01 to 2.0% under mean-annual streamflow and up to 4.5% under mean-August streamflow. Measured and predicted environmental concentrations resulted in 17-β-estradiol equivalency quotients ranging from 0.002 to 5.0 ng L-1 indicating low-to-moderate risk of fish endocrine disruption. Results from the fish exposure experiments showed low (0.5- to 3.2-fold) vitellogenin induction in adult males.