Public Water Research Articles

Building the social. A query into the societal impact of the Pompeian water supply

This study explores the importance of the means of ensuring water supply in the formation of the architectural profile and basic social organization of Pompeii. It sees the city’s domestic water supply, for over two centuries ensured through rainwater-harvesting areas, basins and cisterns situated mainly in and below the many atria, as a stabilizing factor of both cityscape and household. Through the introduction of the city aqueduct in the 1st century AD and the creation of a generous network of public fountains this situation changes and the need to maintain the traditional organization of the “houseful”, comprising enlarged family, slaves and dependents of various kind including shopkeepers, is lessened; the physical proximity between those of different status renegotiated. This development, witnessed in adaptations of the architecture, can be followed through close study of the standing structures in Insula V 1. The hallmarks are the creation of upperfloor living quarters seemingly independent from the life of the large households of the atrium houses, and in parallel the introduction of private water lines from the city aqueduct. The remodelling that resulted in the creation of the double-atrium house of Caecilius Iucundus is focal to the discussion since it offers a coeval chronological fix point in the AD 40s for both remodelling and obtention of piped water. Given that the change in the domestic architecture observed was merely in its embryonic state in AD 79, the tenability to attribute a lower dating than that traditionnaly attributed not just to the private lines, but to the city’s distribution system of public aqueduct water as well, is reasoned. The particularities of Pompeii’s geomorphological situation and political status and how they impacted the discussed change in social relationships are also raised.

Urban green spaces and public realm design in Cairo: Enhancing quality of life and environmental sustainability

The paper explores the pressing challenges and promising initiatives in enhancing urban green spaces and the public realm in Cairo, a metropolis grappling with rapid population growth and environmental degradation. As the city struggles with density, air pollution, and a shortage of green areas—far below the recommended standard for urban health—the article highlights key efforts to revitalize public spaces. Notable projects include the creation of large parks like Al-Azhar Park, the redevelopment of the Nile riverfront through projects such as Mamsha Ahl Misr, and the introduction of green infrastructure solutions like street trees, green roofs, and sustainable urban drainage systems. Despite these advancements, Cairo faces significant obstacles, including limited public land, budget constraints, and water scarcity. However, there are opportunities to address these challenges through innovative urban agriculture, public-private partnerships, and community participation in green space development. The paper suggests that through continued investment and thoughtful urban design, Cairo can foster a more sustainable, livable environment. By integrating green infrastructure into future development projects, the city holds potential to transform its landscape and improve the quality of life for its residents in the coming decades.

Environmental Public Health Tracking in England- support for Health Impact Assessments

Abstract Environmental epidemiology is a key function for the public health service with regards to investigating the public health effects of environmental hazards, monitoring the public health efforts to control the environmental risks, and providing the evidence that informs decisions making and preparedness. At the United Kingdom Health Security Agency (UKHSA), the Environmental Public Health Tracking (EPHT) Programme, initiated in 2010, has developed a number of data streams to help link environment and health data, to support Health Impact Assessment (HIA). The main aims of the EPHT programme in England are to: 1. Identify populations at risk from exposure to significant environmental and chemical hazards 2. Investigate relationships between hazard and disease 3. Inform public health policy making 4. Optimise intervention and prevention strategies 5. Generate hypotheses for further research. Such EPHT functions are based on three key components: a) by building a national EPHT program that integrates surveillance of environmental hazards, exposures and related health outcomes, to allow data linkage and assessment of environmental and health information; b) strengthening the epidemiology science, by conducting research and training of the workforce and c) developing strategies for response to immediate risks, incidents and preparing for future risks. Examples to support HIA include a) developing an air pollution exposure surveillance work programme, that has designed a pilot population vulnerability indicator; b) developing indicators for climate change impacts for public health, c) reporting regularly on the health impacts of public fluoridation water supply schemes (as mandated by Government) and d) exploring risk factors associated with elevated blood lead concentration in children, through laboratory reporting to surveillance systems. The talk will highlight some examples of practice and outline how the EPHT programme in England has supported HIA practices.

Cancer incidence associations with drinking water arsenic levels and disinfection methods in Maine, USA

ABSTRACT Maine is a largely rural state where nearly half of the population uses drinking water from private wells. Arsenic (As) is present in some groundwater in the state and has been linked to cancer, and a lack of testing and treatment may expose people with private wells to elevated As levels. Disinfection byproducts (DBPs) include known and suspected carcinogens that form when chlorine or chloramines are added to water. People served by public water systems may be exposed to elevated levels of regulated DBPs such as trihalomethanes and haloacetic acids associated with chlorine and/or unregulated nitrogenous DBPs, or N-DBPs, such as nitrite and N-nitrosodimethylamine associated with chloramines. Contrary to initial expectations, there were no significant associations between median town As in well water and bladder, lung, kidney, or skin cancer incidence. Furthermore, bladder, melanoma, and other skin cancer incidence rates were negatively correlated with the percent of the town population using private wells. Analysis of cancer incidence associated with chlorine and chloramine disinfection showed elevated melanoma, and other skin cancer with chloramine use and elevated bladder and non-melanoma skin cancer with chlorine use compared to the no disinfectant case. We recommend more research on the links between disinfectant use and cancer.

Effects of glyphosate based herbicide exposure in early developmental stages of Physalaemus gracilis

The impact of environmental pollutants has been a focus of investigation in recent years. Studies assessing the effects of these pollutants are essential for understanding the challenges faced by non-target species. Among the many substances used for agricultural purposes, the herbicide glyphosate is one of the most widely marketed in recent years. This broad-spectrum herbicide is commonly used to protect a variety of crops. In this study, we evaluated the effects of chronic glyphosate exposure on a native amphibian species, Physalaemus gracilis. Amphibians, which develop in aquatic environments, are highly sensitive to pesticides. Because of this, we investigated morphological, physiological, behavioral, and biochemical parameters in the early stages of development. The animals were exposed to environmentally relevant concentrations of a glyphosate-based herbicide (0, 100, 350, and 700 µg L⁻¹) during their first seven days of life. As a result, we observed impairments in anti-predatory behavior, reduced body mass index, and scaled mass index, malformations of the mouth and intestine, increased acetylcholinesterase activity, cardiotoxicity, and oxidative stress. These findings underscore the importance of studying native non-target species and highlight the need to evaluate the effects of environmentally relevant concentrations, as well as to review legislation regarding permissible levels of glyphosate in surface water and public water supplies.

Saltwater intrusion simulations in coastal karstic aquifers related to climate change scenarios

Coastal zones are crucial ecosystems supporting significant biodiversity and pertinent socio-economic activities. However, anthropogenic development contributes to socio-environmental complexities, particularly public water supply threats caused by climate change. This research presents a case study on the north-western coast of Yucatan, Mexico, which models potential saltwater intrusion in groundwater for multiple projections of sea level rise and recharge change due to climate change and its implications for the public water supply of the regional population and ecosystem. For this purpose, a previously calibrated and validated numerical model is employed, adapting its boundary conditions, keeping its calibrated hydrogeologic parameters, and considering the 2040 and 2100 climate change projections. Simulation results show that under these projections, significant saltwater intrusion may occur, reducing freshwater thickness due to increased salinity in groundwater and a loss of freshwater sources resulting from brackish-saline wedge intrusion. These scenarios are of particular concern as freshwater in this coastal region is the main source for public water supply and for freshwater input in coastal ecosystems. Moreover, this study underscores the susceptibility of karstic aquifers to salinization, especially in the face of rising sea levels, given their unique hydrogeological characteristics and substantial responsiveness to marine forcings. In spite of the uncertainties in global climate change predictions, this study enhances our understanding of the dynamics of these unique aquifers, and presents future saltwater intrusion projections that offer valuable technical insights to design and implement pertinent and resilient coastal aquifer management strategies.

Effects of The Cistern Program on Environmental Recovery and Desertification Mitigation in The Semi-Arid Region of Paraíba

Objective: This study aims to analyze the impact of the Cistern Program on mitigating desertification and promoting environmental recovery in the semi-arid region of Paraíba, focusing on the municipalities of Esperança, Lagoa Seca, and São Sebastião de Lagoa de Roça. Theoretical Framework: The research is based on studies addressing the effects of climate change and water scarcity in Brazil’s semi-arid region. Theories of public water policies and strategies for living with the semi-arid climate were also examined, with a focus on the role of cisterns in ensuring water security. Method: This descriptive study employs geotechnologies such as Geographic Information Systems (GIS) and remote sensing to develop desertification maps and track the distribution of cisterns. Data from the Trends.Earth plugin and images from MapBiomas were used to analyze soil degradation between 2004 and 2020. Results and Discussion: The results indicate that the Cistern Program significantly contributed to reducing soil degradation and increasing vegetation cover. Continuous access to water enabled the adoption of sustainable agricultural practices and enhanced environmental resilience in the studied areas. Research Implications: This study contributes to the formulation of public policies that promote water security and sustainable development, reinforcing the importance of social technologies for living in the semi-arid region. Originality/Value: The study provides a novel analysis of the effectiveness of the Cistern Program in combating desertification in the semi-arid region of Paraíba, highlighting its relevance for environmental sustainability policies.

Principal Component Analysis (PCA) of MALDI-TOF for the Identification of Waterborne Pathogenic Bacteria

The study focuses on the application of Principal Component Analysis (PCA) combined with MALDI-TOF MS (Matrix-Assisted Laser Desorption/Ionization-Time of Flight Mass Spectrometry) for the identification of waterborne pathogenic bacteria in urban water networks. In this comprehensive research, 168 bacterial strains were meticulously isolated from the water networks of Abidjan, Côte d'Ivoire, a region known for its inadequate wastewater treatment infrastructure. The analysis aimed to rapidly and precisely identify these bacterial pathogens, leveraging the power of MALDI-TOF MS and the sophisticated data reduction capabilities of PCA. This approach not only accelerates the identification process but also enhances the accuracy of detecting various pathogens. The study identified a diverse range of pathogens, including Pseudomonas aeruginosa, Escherichia coli, Salmonella, Shigella, Vibrio cholerae, Morganella morganii, Proteus mirabilis, Acinetobacter baumannii, Klebsiella pneumoniae, Providencia rettgeri, Providencia stuartii, Aeromonas hydrophila, Bacillus cereus, Lysinibacillus fusiformis, Lysinibacillus sphaericus, and Staphylococcus aureus. These findings underscore the critical public health risks posed by microbial contamination in water networks, particularly in areas with deficient waste management systems. This study highlights the necessity for improved wastewater management practices, robust public health strategies, and regular monitoring to mitigate the risks associated with waterborne pathogens. Moreover, the integration of PCA with MALDI-TOF MS proves to be a powerful tool for enhancing the efficiency and accuracy of pathogen identification in environmental water samples, offering a promising solution for better public health protection and water quality management in urban settings.

Impact of dental fluorosis on the oral health-related quality of life: a systematic review.

The aim of this systematic review is to investigate the literature to assess the effect of dental fluorosis on the Oral Health-Related Quality of Life (OHRQoL). Included studies were epidemiological investigations, clinical trials, or human studies that directly compared the impact on OHRQoL between individuals with dental fluorosis and those without, utilizing valid OHRQoL assessment tools. The searches were conducted up to March 2024 in databases, including PubMed, Scielo, LILACS, Scopus, Web of Science, Embase, and the Virtual Health Library. Additionally, gray literature sources such as Google Scholar, OpenGrey, Ibict/BDTD, and ProQuest were searched. Reference lists were also manually reviewed for potential eligible studies. The risk of bias in cohort studies was assessed using the Newcastle-Ottawa Scale (NOS), while its modified version was employed for cross-sectional studies. A narrative synthesis of the results was conducted. 16 studies were included in this Systematic Review. In total, 16,314 participants, aged 8 to 18, were assessed across the studies. Most of the included studies were cross-sectional, except for one cohort study. In assessing OHRQoL across different age groups and severities of dental fluorosis, the impact varied. A negative association between dental fluorosis and OHRQoL was found in 9 of the included studies, a positive association was found in 1 study, and no significative association was identified in 6 studies. Limitations in the included studies primarily pertained to cross-sectional designs, with significant issues such as the absence of sample size calculations, lack of non-response rate reporting, limited consideration of confounding factors, and substantial heterogeneity stemming from diverse diagnostic methods and assessment tools. The findings of the systematic review demonstrate a complex and varied relationship between dental fluorosis and OHRQoL in children and adolescents. These conclusions may have limitations in scientific evidence. The findings emphasize the need for further investigations to explore the intricate aspects of this relationship and identify contributing factors to varying outcomes. Dental caries preventive fluoridated measures might be indicated even if there would be a risk for mild dental fluorosis as the fluoridated public water. This systematic review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) under number: CRD42020186552.

Legionella in Primary School Hot Water Systems from Two Municipalities in the Danish Capital Region.

Legionella contamination in public water systems poses significant health risks, particularly in schools where vulnerable populations, including children, regularly use these facilities. This study investigates the presence of Legionella in the hot water systems from 49 primary schools across two municipalities in the Danish capital region. Water samples were collected from taps in each school, and both first-flush and stabile temperature samples were analysed for Legionella contents. The findings revealed that 97% of schools in Municipality 1 and 100% in Municipality 2 had Legionella in their hot water systems. The content of Legionella colonies was significantly higher in schools in Municipality 1, which was probably because of overall lower water temperatures. At stabile temperatures, 76% and 50% of the schools in the two municipalities exceeded the European Union's recommended limit of 1000 CFU/L. Stabile peripheral water temperatures were achieved after 3 min. Tap water temperatures above 54 °C and central tank temperatures above 59 °C were associated with Legionella contents below 1000 CFU/L. This study highlights the need for more stringent Legionella control procedures in schools, including higher water temperatures and refining Legionella reducing interventions with the addition of regular flow and draining procedures.

Ultrastructural evaluation of adverse effects on dentine formation from systemic fluoride application in an experimental mouse model.

Fluoride is widely used in dentistry for its caries prevention. To reduce dental caries, the optimal fluoride concentration of public water supplies in the United States is 0.7 ppm. However, excessive systemic fluoride consumption can lead to dental/enamel fluorosis. Numerous studies have explored the effects of fluoride on enamel and enamel-forming cells. However, research on systemic fluoride's impact on dentine is limited, particularly the effect of fluoride on the structure of the dentine-pulp complex. Therefore, this study aimed to identify how excessive fluoride affects dentine microstructure using an experimental mouse model. C57BL6/J male mice (6-9 weeks old) were randomized into four groups (Fluoride at 0, 50, 100, or 125 ppm in drinking water) (n = 4/group). Mice were provided water adlibitum for 6 weeks along with fluoride-free food. Thereafter, mandibular incisors were analysed. Enamel phenotypes were evaluated using light microscopy and quantitative light-induced fluorescence (QLF) to measure fluorosis levels. Dentine morphology was evaluated using micro-CT, scanning electron microscopy (SEM), SEM-EDX (energy-dispersive X-ray), microhardness test and histological imaging. Data were analysed using one-way ANOVA with Dunnett's multiple comparisons as a post hoc test and the Kruskal-Wallis test with Dunn's multiple comparisons post hoc test (p < .05). Mice treated with fluoride at 50-125 ppm developed enamel hypoplasia in their erupting incisors and micro-CT imaging revealed that fluoride 125 ppm caused external resorption of the growing incisor. Dentine mineral density, dentine volume decreased compared with the 0 ppm control, while pulp volume increased compared with the 0 ppm control group. SEM showed wider predentine layer and abnormalities in calcified matrix vesicles derived from odontoblasts in fluoride 100 and 125 ppm groups. Vickers microhardness of dentine significantly decreased in the high-dose group. Fluoride-induced dentine hypoplasia in a dose-dependent manner. Histological evaluation showed excessive fluoride 125 ppm induced micro abscess formation and inflammatory cell infiltration. Fluoride induced dentine dysplasia with a dentine microstructure resembling hypophosphatasia. High doses of systemic fluoride can cause dentine dysplasia. Both three-dimensional and microstructural analyses showed the structural, chemical and mechanical changes in the dentine and the mineralized tissue components, along with external resorption and pulp inflammation.

Identifying optimal funding allocations for public water infrastructure improvements under uncertainty

Diversified and locally managed funding strategies bring substantial benefits to water infrastructure investments across financial, social, institutional, and political spheres. However, these strategies often occupy a secondary role in the public sector's capital allocation process. We outline optimal funding strategies for water infrastructure by zeroing in on communities' specific needs and navigating two types of uncertainty—historical and priority uncertainty—across both long-run (multi-decade) and short-run (recent years) timeframes. Employing Modern Portfolio Theory (MPT), our approach pinpoints optimal funding distribution both across and within categories (namely, individual counties) based on their funding needs. By comparing these distributions with Tennessee's Clean Water State Revolving Fund's historical funding approach, we benchmark how risk and socioeconomic factors influenced past decisions. This analysis yields optimal allocations that inform which counties should be given priority by public funding agencies, moving toward portfolios that adeptly balance risk with funding necessity. Our methodology is executed in two stages, each bearing distinct implications. The initial stage seeks to prioritize groups of counties based on their funding needs, considering both immediate and long-term contexts, in line with what government agencies might aim to achieve. The subsequent stage refines the equilibrium between risk and need at a more detailed level within these groups, facilitating risk diversification that effectively addresses both short- and long-term funding requirements.

Turn off the faucet: Can individual meters reduce water consumption?

When consumption of water and other utilities is measured collectively for many households and the payment of such services is equally shared among members of the group, individuals may use more than what is socially optimal. In this paper, we evaluate how the installation of individual meters affects water consumption. Using administrative data from the public water utility company in Quito, Ecuador, and an event study approach, it is estimated that water consumption decreases by about 20% as a result of the introduction of individual metering. The effect is large and economically significant: in order to obtain the same effect using the price mechanism in Quito, prices would have to increase by at least 66%. Individual water metering could be a useful tool to curve down consumption in both developing and developed countries.

Breaking Water Laws in the Murray‐Darling Basin: Understanding Water Compliance Challenges and Stakeholder Perceptions

AbstractClimate change will put pressure on irrigated agriculture, increasing water scarcity and possible non‐compliance with water regulations. This is especially true in areas such as the Murray‐Darling Basin (MDB), Australia, an area where water resources have been overallocated. Understanding the expected penalties and probability of detection and prosecution of water theft faced by irrigators is important for understanding the incentives for water compliance. We analyze state‐level compliance action data and undertake a detailed case study of estimating the real penalty value of water theft in New South Wales (NSW), the largest MDB state. This analysis is supplemented with qualitative comment on compliance issues from 63 MDB stakeholder interviews. Although findings from random audits suggest that only a small percentage of irrigators commit water theft offenses, the average probabilities of audit detection and prosecution for water theft in NSW between 2018/19 and 2020/21 were low, leading to an average real expected penalty value of stealing water well below existing market prices. Stakeholder interviews confirmed that the majority did not believe there were serious water theft or water compliance challenges—whereas recent secondary survey data suggests that the general public perceives water theft and compliance as a serious and ongoing challenge in the MDB and more needs to be done to address it. Three recommendations for data and policy reform are proposed, namely: (a) improving compliance data and reporting; (b) increasing the probability of detection and prosecution; and (c) increasing penalties, regulator visibility, and reforming legislation. Results illustrate that even countries with highly advanced water governance require data improvements, along with sufficient levels of compliance activities and penalties for effective deterrence and stakeholder confidence.

Multivalent bifunctional nanobody to enhance the sensitivity of direct competitive chemiluminescence immunoassay for the detection of microcystin LR in lake water

Microcystin-LR (MC-LR), a toxic cyanobacterial toxin in freshwater, poses significant health and ecological risks due to its ability to induce cell apoptosis and liver damage. Sensitive detection of MC-LR is crucial for public health and water safety. In this work, we engineered a multivalent bifunctional nanobody (A2.3-C4-SBP) by fusing the anti-MC-LR nanobody gene (A2.3) with self-assembling peptides (C4) and a streptavidin-binding peptide (SBP). A2.3-C4-SBP was directionally immobilized on the ELISA microplate via streptavidin-mediated to develop a multivalent bifunctional nanobody-based chemiluminescent immunoassay (MBN-CLIA) for MC-LR detection in lake water. The IC50 of the A2.3-C4-SBP heptamer based CLIA was 5.80 ng/mL, and the LOD (IC10) was 0.33 ng/mL, which were 9.51-fold and 1.82-fold lower, respectively, than those of the A2.3-SBP monomer based CLIA. Additionally, the IC50 and LOD were 1.26-fold and 1.82-fold lower, respectively, than those of the A2.3-C4-SBP heptamer without streptavidin-mediated directional immobilization. In summary, this work developed a sensitive, rapid and simple immunoassay for the detection of MC-LR in lake water based on multivalent bifunctional nanobodies. Furthermore, the proposed combined strategy of nanobody multimerization and directed immobilization is simple to operate and has great potential to improve the sensitivity and signal amplification of various immunoassays.

Groundwater in Katowice - center of a large urban and deep coal mining area in Poland

The paper presents the groundwater resources of Katowice and the results of studies conducted to identify prospective areas in aquifers with sufficient water resources for the location of public water intakes. The city of Katowice is the capital of Upper Silesia, the largest urban-industrial area in Poland, the region with a highly developed hard coal mining and many other different industries covering almost the entire scope of the economy. Due to long term drainage of mines causing the depletion and deterioration of groundwater and surface water resources, the main municipal water intakes have been located outside Katowice. Most of the pumped mine water is discharged into surface waters, causing significant salinity of water and disallow its use for municipal or industrial purposes in Katowice. The water collection and supply system is very extensive and covers a significant part of the Silesian agglomeration which is why Katowice is supplied with water from surface water intakes located outside the city. According to older published materials, such as the Hydrogeological map of Poland, there were no aquifers in the city that could have been used to supply the city with drinking water, however recent studies have shown that groundwater in the Quaternary aquifers in the western part of the city can be used to supply the city with public water. Less productive, Quaternary aquifers in north-eastern parts of the city may constitute the basis for drinking water supply in emergency situations, when surface intakes cannot be used, such as toxic, radiological or viral contamination or damage to the water supply network eg. as a result of an earthquake or warfare.

A geospatial assessment of the resilience of municipal water supply to flooding in Nowshera District, Pakistan

Post-disaster functionality of the potable water supply infrastructure is crucial for maintaining public health and safety. The failure of the water supply system may harm inhabitants and significant users, which can impact other services and various types of infrastructures. It is vital to assess climate change impacts on water resources to ensure resilience and sustainable management. The study assessed the resilience of 22 municipal water schemes using an indicator-based framework, How Tough is Wash (HTIW), across six domains: environment, infrastructure, community governance, water supply management, supply chains, and institutional support. The sites of municipal water supply were purposively selected based on specific criteria to include those water supply schemes which have been directly affected by flooding or are vulnerable to the impact of the flood. The resilience scores ranged from (6 to 7.5) for schemes with very low resilience, (7.5 to 10.5) for those classified as poor, and (10.6 to 16.5) for schemes considered moderately resilient. It was discovered that protective measures against the risk of flood were negligible. Community engagement governance and water supply management needed to be stronger. Local governments can pinpoint current advantages and disadvantages by utilizing these metrics and their impact on the public water supply's resilience and strategically allocate resources for optimal outcomes. Furthermore, the metrics that have been suggested simplify and unify the multiple dimensions of the elements, enabling decision-makers to optimize the measures.

Risk Management Associated with Surface Sources of Public Water Supply in Urban and Rural Areas in a Developing Country

Risk Management Associated with Surface Sources of Public Water Supply in Urban and Rural Areas in a Developing Country

Mixed contaminant exposure in tapwater and the potential implications for human-health in disadvantaged communities in California

Water is an increasingly precious resource in California as years of drought, climate change, pollution, as well as an expanding population have all stressed the state's drinking water supplies. Currently, there are increasing concerns about whether regulated and unregulated contaminants in drinking water are linked to a variety of human-health outcomes particularly in socially disadvantaged communities with a history of health risks. To begin to address this data gap by broadly assessing contaminant mixture exposures, the current study was designed to collect tapwater samples from communities in Gold Country, the San Francisco Bay Area, two regions of the Central Valley (Merced/Fresno and Kern counties), and southeast Los Angeles for 251 organic chemicals and 32 inorganic constituents. Sampling prioritized low-income areas with suspected water quality challenges and elevated breast cancer rates. Results indicated that mixtures of regulated and unregulated contaminants were observed frequently in tapwater throughout the areas studied and the types and concentrations of detected contaminants varied by region, drinking-water source, and size of the public water system. Multiple exceedances of enforceable maximum contaminant level(s) (MCL), non-enforceable MCL goal(s) (MCLG), and other health advisories combined with frequent exceedances of benchmark-based hazard indices were also observed in samples collected in all five of the study regions. Given the current focus on improving water quality in socially disadvantaged communities, our study highlights the importance of assessing mixed-contaminant exposures in drinking water at the point of consumption to adequately address human-health concerns (e.g., breast cancer risk). Data from this pilot study provide a foundation for future studies across a greater number of communities in California to assess potential linkages between breast cancer rates and tapwater contaminants.

The role of fault pathways for modern and deep recharge to a semi-confined aquifer: revised analysis of modern water leakage pathways in the Davis wellfield, Memphis, Tennessee, USA

Hydrologic tracer, borehole log and geophysical data provide new insight into recharge sources and pathways to the semi-confined Memphis aquifer in the Davis wellfield, Memphis, Tennessee, U.S.A. New data and recent studies highlight the importance of faults as potential pathways for the migration of modern water into the Memphis aquifer, an important regional public, industrial, and agricultural water supply. Geochemical and environmental tracer data collected over the past 28 years, combined with hydrologic, stratigraphic, and structural data, were used to evaluate changes in water quality and different recharge pathways to the Memphis aquifer. Assessment of stratigraphic and structural relationships argue for the wellfield being bound by a fault along the bluff line (west) and another fault or faults along the eastern and southeastern margins. Modern water recharge (< 60 years old) occurs through the fault along the western boundary of the wellfield, whereas modern water and, seasonally, deep-seated (helium-bearing) fluids recharge along the fault on the southeastern margin. Each recharge source and pathway present different vulnerabilities, suggesting that the role of faults in wellfields within active tectonic regions needs to be assessed.