National trends in drinking water quality violations

Molecular Engineering of 2D Nanomaterial Field-Effect Transistor Sensors: Fundamentals and Translation across the Innovation Spectrum

Over the last decade, 2D layered nanomaterials have attracted significant attention across the scientific community due to their rich and exotic properties. Various nanoelectronic devices based on these 2D nanomaterials have been explored and demonstrated, including those for environmental applications. Here, the fundamental attributes of 2D layered nanomaterials for field-effect transistor (FET) sensors and tunneling FET (TFET) sensors, which provide versatile detection of water contaminants such as heavy-metal ions, bacteria, nutrients, and organic pollutants, are discussed. The major challenges and opportunities are also outlined for designing and fabricating 2D nanomaterial FET/TFET sensors with superior performance. Translation of these FET/TFET sensors from fundamental research to applied technology is illustrated through a case study on graphene-based real-time FET water sensors. A second case study centers on large-scale sensor networks for water-quality monitoring to enable intelligent drinking water and river-water systems. Overall, 2D nanomaterial FET sensors have significant potential for enabling a human-centered intelligent water system that can likely be applied to other precarious water supplies around the globe.

Approximating Community Water System Service Areas to Explore the Demographics of SDWA Compliance in Virginia

Although the United States Safe Drinking Water Act (SDWA) theoretically ensures drinking water quality, recent studies have questioned the reliability and equity associated with community water system (CWS) service. This study aimed to identify SDWA violation differences (i.e., monitoring and reporting (MR) and health-based (HB)) between Virginia CWSs given associated service demographics, rurality, and system characteristics. A novel geospatial methodology delineated CWS service areas at the zip code scale to connect 2000 US Census demographics with 2006–2016 SDWA violations, with significant associations determined via negative binomial regression. The proportion of Black Americans within a service area was positively associated with the likelihood of HB violations. This effort supports the need for further investigation of racial and socioeconomic disparities in access to safe drinking water within the United States in particular and offers a geospatial strategy to explore demographics in other settings where data on infrastructure extents are limited. Further interdisciplinary efforts at multiple scales are necessary to identify the entwined causes for differential risks in adverse drinking water quality exposures and would be substantially strengthened by the mapping of official CWS service boundaries.

Comparison of potential drinking water source contamination across one hundred U.S. cities

Drinking water supplies of cities are exposed to potential contamination arising from land use and other anthropogenic activities in local and distal source watersheds. Because water quality sampling surveys are often piecemeal, regionally inconsistent, and incomplete with respect to unregulated contaminants, the United States lacks a detailed comparison of potential source water contamination across all of its large cities. Here we combine national-scale geospatial datasets with hydrologic simulations to compute two metrics representing potential contamination of water supplies from point and nonpoint sources for over a hundred U.S. cities. We reveal enormous diversity in anthropogenic activities across watersheds with corresponding disparities in the potential contamination of drinking water supplies to cities. Approximately 5% of large cities rely on water that is composed primarily of runoff from non-pristine lands (e.g., agriculture, residential, industrial), while four-fifths of all large cities that withdraw surface water are exposed to treated wastewater in their supplies.

Evaluating water quality using social media and federal agency data

United States Environmental Protection Agency (USEPA) drinking water violation report is currently one of the most reliable measures of evaluating United States drinking water quality. While states continuously strive to comply with federal water quality standards making this documentation continuously relevant, consumers are likely to perceive water quality through sensory aesthetics or physical and virtual social networks. This research quantifies the relationship between consumer perceptions and government-reported drinking water quality to provide insights to state water managers and policymakers. We evaluated consumer perceptions of tap water using weekly social media data. The online search returned 898,709 mentions and 799,035 posts. Net sentiment, measured as the number of negative posts minus the number of positive posts divided by the number of posts expressing sentiment, was determined and ranged from -100 to 100. Net sentiment was uncorrelated with USEPA weekly water quality violations for most states. Net sentiment was correlated with violations related to arsenic standards (-0.223) and a total number of violations (-0.220) for Washington. For California, net sentiment was correlated with violations related to disinfectants and other organic compounds (-0.295). In many cases, water violations in one city became national news, which eclipsed local water issues circulating on social media.

Spatial-temporal targeted and non-targeted surveys to assess microbiological composition of drinking water in Puerto Rico following Hurricane Maria

Loss of basic utilities, such as drinking water and electricity distribution, were sustained for months in the aftermath of Hurricane Maria's (HM) landfall in Puerto Rico (PR) in September 2017. The goal of this study was to assess if there was deterioration in biological quality of drinking water due to these disruptions. This study characterized the microbial composition of drinking water following HM across nine drinking water systems (DWSs) in PR and utilized an extended temporal sampling campaign to determine if changes in the drinking water microbiome were indicative of HM associated disturbance followed by recovery. In addition to monitoring water chemistry, the samples were subjected to culture independent targeted and non-targeted microbial analysis including quantitative PCR (qPCR) and genome-resolved metagenomics. The qPCR results showed that residual disinfectant was the major driver of bacterial concentrations in tap water with marked decrease in concentrations from early to late sampling timepoints. While Mycobacterium avium and Pseudomonas aeruginosa were not detected in any sampling locations and timepoints, genetic material from Leptospira and Legionella pneumophila were transiently detected in a few sampling locations. The majority of metagenome assembled genomes (MAGs) recovered from these samples were not associated with pathogens and were consistent with bacterial community members routinely detected in DWSs. Further, whole metagenome-level comparisons between drinking water samples collected in this study with samples from other full-scale DWS indicated no significant deviation from expected community membership of the drinking water microbiome. Overall, our results suggest that disruptions due to HM did not result in significant and sustained deterioration of biological quality of drinking water at our study sites.

On-Chip Optical Anodic Stripping with Closed Bipolar Cells and Cathodic Electrochemiluminescence Reporting

The aim of this work was to develop a simple, accessible, and point-of-use sensor to measure heavy metal ions in water in low-resource areas that cannot accommodate expensive or technical solutions. This report describes a new bipolar electrochemical sensor platform that reimagines conventional anodic stripping voltammetry in a wireless bipolar format with an optical electrochemiluminescent readout that can be quantified with any simple optical sensor like that found on most modern cell phone cameras. We call this technique as optical anodic stripping. Using a new nonlithographic fabrication process, devices could be produced rapidly and simply at <$1/sensor. The sensing scheme was developed, characterized, and optimized using electrochemical and optical methods. Quantitation of Pb²⁺ in both lab and natural water samples was rapid (2-3 min), accurate, precise, and highly linear in the 25-1000 ppb range and was shown to be sufficiently selective in the presence of other common heavy metal ions such as Cu²⁺, Cd²⁺, and Zn²⁺.

A pilot study on the feasibility of testing residential tap water in North Carolina: implications for environmental justice and health

BACKGROUND

In 2015 alone, community water systems serving about 21 million Americans violated the United States Environmental Protection Agency's (US-EPA) water quality standards. While water at community treatment and distribution centers is regularly monitored and tested, little is known about pollutants in the water systems at the household level.

AIMS

This pilot study assessed the feasibility of (1) testing for the presence and concentration of 14 contaminants and physicochemical parameters in household tap water in a low-income neighborhood and (2) using community engagement for recruitment and citizen science approaches to data collection.

METHODS

We used a multistage approach that included geo-mapping to delineate testing sites, community engagement for recruitment and citizen science approaches to increase the response rate. We used a 14-in-one dipstick test designed to measure trace amounts of heavy metals, non-metallic elements, and physicochemical water properties in drinking water in a sample of 70 homes.

RESULTS

In 50%, 25%, and 7% of water samples tested, the concentration of mercury, lead, and chromium, respectively, were higher than US-EPA drinking water standards. Citizen science approaches were effective for increasing response rates and low-income household participation in water quality testing.

SIGNIFICANCE

The overlap between poverty, older homes, and high concentrations of potentially toxic metals in drinking water presents concerns for community health. Our pilot community engagement and citizen science approaches are likely scalable and would be of benefit to both the scientific community and to municipalities with constrained budgets. Future studies may examine the role of the principles of environmental justice in the distribution and prevalence of toxic elements in drinking water.

Addressing Urgent Questions for PFAS in the 21st Century

Despite decades of research on per- and polyfluoroalkyl substances (PFAS), fundamental obstacles remain to addressing worldwide contamination by these chemicals and their associated impacts on environmental quality and health. Here, we propose six urgent questions relevant to science, technology, and policy that must be tackled to address the "PFAS problem": (1) What are the global production volumes of PFAS, and where are PFAS used? (2) Where are the unknown PFAS hotspots in the environment? (3) How can we make measuring PFAS globally accessible? (4) How can we safely manage PFAS-containing waste? (5) How do we understand and describe the health effects of PFAS exposure? (6) Who pays the costs of PFAS contamination? The importance of each question and barriers to progress are briefly described, and several potential paths forward are proposed. Given the diversity of PFAS and their uses, the extreme persistence of most PFAS, the striking ongoing lack of fundamental information, and the inequity of the health and environmental impacts from PFAS contamination, there is a need for scientific and regulatory communities to work together, with cooperation from PFAS-related industries, to fill in critical data gaps and protect human health and the environment.

Virus Removal and Inactivation Mechanisms during Iron Electrocoagulation: Capsid and Genome Damages and Electro-Fenton Reactions

Virus destabilization and inactivation are critical considerations in providing safe drinking water. We demonstrate that iron electrocoagulation simultaneously removed (via sweep flocculation) and inactivated a non-enveloped virus surrogate (MS2 bacteriophage) under slightly acidic conditions, resulting in highly effective virus control (e.g., 5-logs at 20 mg Fe/L and pH 6.4 in 30 min). Electrocoagulation simultaneously generated H₂O₂ and Fe(II) that can potentially trigger electro-Fenton reactions to produce reactive oxygen species such as ^•OH and high valent oxoiron(IV) that are capable of inactivating viruses. To date, viral attenuation during water treatment has been largely probed by evaluating infective virions (as plaque forming units) or genomic damage (via the quantitative polymerase chain reaction). In addition to these existing means of assessing virus attenuation, a novel technique of correlating transmission electron micrographs of electrocoagulated MS2 with their computationally altered three-dimensional electron density maps was developed to provide direct visual evidence of capsid morphological damages during electrocoagulation. The majority of coliphages lost at least 10-60% of the capsid protein missing a minimum of one of the 5-fold and two of 3- and 2-fold regions upon electrocoagulation, revealing substantial localized capsid deformation. Attenuated total reflectance-Fourier transform infrared spectroscopy revealed potential oxidation of viral coat proteins and modification of their secondary structures that were attributed to reactive oxygen species. Iron electrocoagulation simultaneously disinfects and coagulates non-enveloped viruses (unlike conventional coagulation), adding to the robustness of multiple barriers necessary for public health protection and appears to be a promising technology for small-scale distributed water treatment.

Pilot-scale expanded assessment of inorganic and organic tapwater exposures and predicted effects in Puerto Rico, USA

A pilot-scale expanded target assessment of mixtures of inorganic and organic contaminants in point-of-consumption drinking water (tapwater, TW) was conducted in Puerto Rico (PR) to continue to inform TW exposures and corresponding estimations of cumulative human-health risks across the US. In August 2018, a spatial synoptic pilot assessment of than 524 organic and 37 inorganic chemicals was conducted in 14 locations (7 home; 7 commercial) across PR. A follow-up 3-day temporal assessment of TW variability was conducted in December 2018 at two of the synoptic locations (1 home, 1 commercial) and included daily pre- and post-flush samples. Concentrations of regulated and unregulated TW contaminants were used to calculate cumulative in vitro bioactivity ratios and Hazard Indices (HI) based on existing human-health benchmarks. Synoptic results confirmed that human exposures to inorganic and organic contaminant mixtures, which are rarely monitored together in drinking water at the point of consumption, occurred across PR and consisted of elevated concentrations of inorganic contaminants (e.g., lead, copper), disinfection byproducts (DBP), and to a lesser extent per/polyfluoroalkyl substances (PFAS) and phthalates. Exceedances of human-health benchmarks in every synoptic TW sample support further investigation of the potential cumulative risk to vulnerable populations in PR and emphasize the importance of continued broad characterization of drinking-water exposures at the tap with analytical capabilities that better represent the complexity of both inorganic and organic contaminant mixtures known to occur in ambient source waters. Such health-based monitoring data are essential to support public engagement in source water sustainability and treatment and to inform consumer point-of-use treatment decision making in PR and throughout the US.

The widespread and unjust drinking water and clean water crisis in the United States

Many households in the United States face issues of incomplete plumbing and poor water quality. Prior scholarship on this issue has focused on one dimension of water hardship at a time, leaving the full picture incomplete. Here we complete this picture by documenting the full scope of water hardship in the United States and find evidence of a regionally-clustered, socially unequal nationwide household water crisis. Using data from the American Community Survey and the Environmental Protection Agency, we show there are 489,836 households lacking complete plumbing, 1,165 community water systems in Safe Drinking Water Act Serious Violation, and 21,035 Clean Water Act permittees in Significant Noncompliance. Further, we demonstrate this crisis is regionally clustered, with the specific spatial pattern varying by the specific form of water hardship. Elevated levels of water hardship are associated with the social dimensions of rurality, poverty, indigeneity, education, and age—representing a nationwide environmental injustice.

Proper water and sanitation access remains an issue for many in the United States. Here the authors estimate and map the full scope of water hardship, including both incomplete plumbing and water quality across the country.

Measurement of free chlorine levels in water using potentiometric responses of biofilms and applications for monitoring and managing the quality of potable water

Residual free chlorine is not monitored continuously at scale in drinking water distribution systems because existing real-time sensor technologies require frequent maintenance, cleaning, and calibration, which makes these products too costly to be used throughout a distribution system. As a result, current measurement approaches require manual sampling, which is not feasible for the consistent monitoring of free chlorine because chlorine concentrations vary significantly throughout pipeline distribution and over time and space. This research presents an alternative and cost-effective method of predicting free chlorine levels in drinking water using graphite electrodes coated with naturally grown microbial biofilms. This Microbial Potentiometric Sensor (MPS) array was installed in a Continuously Mixed Batch Reactor (CMBR), and drinking water containing variable free chlorine concentrations. The chlorine concentrations were introduced in a controlled manner, and the MPS signals were monitored over time. MPS signals were measured from the change in Open Circuit Potential (OCP) across the MPS array in real-time. An empirically derived relationship between the normalized change in OCP and free chlorine was established by fitting individual and average MPS data to a decaying exponential growth function in order to predict free chlorine levels. The results show that free chlorine can be predicted with reasonable accuracy, with model validation showing an average absolute error of ±0.09 ppm below 1.1 ppm and ±0.30 ppm between 1.1 and 2.7 ppm. However, the accuracy of predictions was reduced at higher free chlorine levels. The researchers conclude that MPS systems may benefit drinking water distribution systems by measuring free chlorine. These advantages of the MPS are especially pronounced in the developing world because this system is inexpensive and does not require routine maintenance or cleaning. The system relies on a naturally forming and regenerating biofilm and an inexpensive potentiometric meter to produce stable measurements.

Addition of lemon before boiling chlorinated tap water: A strategy to control halogenated disinfection byproducts

Chlorine disinfection is required to inactivate pathogens in drinking water, but it inevitably generates potentially toxic halogenated disinfection byproducts (halo-DBPs). A previous study has reported that the addition of ascorbate to tap water before boiling could significantly decrease the concentration of overall halo-DBPs in the boiled water. Since the fruit lemon is rich in vitamin C (i.e., ascorbic acid), adding it to tap water followed by heating and boiling in an effort to decrease levels of halo-DBPs was investigated in this study. We examined three approaches that produce lemon water: (i) adding lemon to tap water at room temperature, termed "Lemon"; (ii) adding lemon to boiled tap water (at 100 °C) and then cooling to room temperature, termed "Boiling + Lemon"; and (iii) adding lemon to tap water then boiling and cooling to room temperature, termed "Lemon + Boiling". The concentrations of total and individual halo-DBPs in the resultant water samples were quantified with high-performance liquid chromatography-tandem mass spectrometry and the cytotoxicity of DBP mixtures extracted from the water samples was evaluated using human epithelial colorectal adenocarcinoma Caco-2 cells and hepatoma HepG2 cells. Our results show that the "Lemon + Boiling" approach substantially decreased the concentrations of halo-DBPs and the cytotoxicity of tap water. This strategy could be applied to control halo-DBPs, as well as to lower the adverse health effects of halo-DBPs on humans through tap water ingestion.

Water Safety in California Public Schools Following Implementation of School Drinking Water Policies

Introduction

Recent legislation requires public and charter schools in California to test drinking water for lead. Our objective was to describe 1) results from this testing program in the context of other available water safety data and 2) factors related to schools and water utilities associated with access to safe drinking water in schools.

Methods

Our study focused on a random sample of 240 California public and charter schools. We used multivariable logistic regression, accounting for clustering of tested water sources in schools, to examine school-level factors associated with failure to meet lead-testing deadlines and any history of water utility noncompliance.

Results

Of the 240 schools, the majority (n = 174) tested drinking water for lead. Of the schools tested, 3% (n = 6) had at least 1 sample that exceeded 15 parts per billion (ppb) (California action level) and 16% (n = 28) exceeded 5 ppb (bottled water standard). Suburban schools had lower odds of being served by noncompliant water systems (OR = 0.17; CI, 0.05–0.64; P = .009) than city schools. Compared with city schools, rural schools had the highest odds of not participating in the water testing program for lead (OR = 3.43; CI, 1.46–8.05; P = .005). Hallways and common spaces and food services areas were the most frequent school locations tested; one-third of all locations sampled could not be identified.

Conclusion

In our study, geography influenced access to safe drinking water in schools, including both water utility safety standards and school lead-testing practices. Considerations for improving the implementation of state lead-testing programs include establishing priority locations for sampling, precisely labeling samples, and developing well-defined testing and reporting protocols.

Development and implementation of water safety plans for groundwater resources in the southernmost city of West Azerbaijan Province, Iran

The transfer of water from the source to the consumption point is always associated with the possibility of contamination in any of its various components. To resolve this problem, the World Health Organization has considered a water safety plan. The purpose of this study is to implement water safety plan in the water supply system of Bukan city. This study was performed on Bukan's water supply system in 2019-20 using a software to guarantee the quality of the water safety plan and the WHO and IWA guidelines. The software checklists were prepared and after confirming the validity of the translation and its facial and content validity, it was completed based on the records of the Water and Sewerage Company and interviews with experts. Out of a total of 440 points of full-application of the program and 392 points for the reviewed phases, 183.6 points were acquired and 43.7% of WSP-coordinated implementation was observed. The highest percentage of WSP-coordinated implementation (75.2%) was assigned to the validation stage with the highest point, and the support program stage had the lowest percentage of performance (1.1%). Among the major components of the water supply system, the final consumption point received the most attention from the system. Given the lifespan of the introduction and use of WSP in the world, it was expected that better results would be obtained from evaluating the implementation and progress of this approach in Bukan's water supply system. However, the implementation rate of this program in this city compared to other cities in Iran, showed that according to the implementation time (one year), the obtained results are relatively convincing and good and the water supply system has a moderate level of safety.

Historical analysis of inverse correlation between soil-transmitted helminthiasis and pancreatic cancer

In this descriptive epidemiological study, the soil-transmitted helminth (STH) burden and pancreatic cancer (PC) mortality rates of different countries and peoples are compared to demonstrate an inverse correlation. Formerly ubiquitous helminth infection possibly played a significant role in defending the human host against PC until the advancement of modern hygiene, with helminth eradication in recent times in developed countries and urban centers. It is posited that a high rate of infection by STH in developing countries and rural areas protects the human host from the development of PC, possibly by immune modulation. This hypothesis is used to explain increased PC rates in minority groups in the United States who had decreased helminth exposure in the late 20th century.

Polymerized Molecular Receptors as Adsorbents to Remove Micropollutants from Water

Organic micropollutants (MPs) are increasing in number and concentration in water systems as a result of human activities. Often from human origin, these micropollutants build up in the environment because organisms lack the mechanisms to metabolize these substances, which cause negative health, ecological, and economic effects. Adsorption-based remediation processes for these compounds often rely on activated carbon materials. However, activated carbons are ineffective against certain MPs, exhibit low removal efficiencies in the presence of common aqueous matrix constituents, and require energy-intensive activation and regeneration processes. To overcome the deficiencies of traditional technologies, novel adsorbents based on molecular receptors offer promising alternative solutions. This Account describes the recent development of polymer adsorbents based on molecular receptors for removing trace organic chemicals from water. Polymer networks based on molecular receptors have high binding affinities for many MPs but, unlike activated carbons, have a specific molecule-binding mechanism that prevents these polymers from being fouled by matrix constituents such as natural organic matter. The size and hydrophobic pocket of the β-cyclodextrin receptor preferentially adsorbs target molecules such as organic micropollutants in the presence of matrix constituents, and the nature of the cross-linker tunes the binding affinity and selectivity of the adsorbent for specific classes of MPs, including those of varying charge and hydrophobicity. β-cyclodextrin polymers also exhibit rapid adsorption kinetics and are easily regenerated. This Account details β-cyclodextrin polymers made with three different cross-linkers, including a polymer that is postsynthetically transformed from a negatively charged polymer to a positively charged polymer to invert the polymer's micropollutant adsorption profile. Morphological constraints have so far limited these cross-linked polymers' ability to be used in commercial applications, but two methods to create larger and more uniformly sized particles for use in flow-through applications are described here. β-Cyclodextrin polymers are useful for trapping organic micropollutants such as bisphenol A, perfluorooctanoic acid, and many kinds of pharmaceuticals and pesticides, but their binding pockets are too large to capture micropollutants that are small or of high polarity. Other molecular receptors such as resorcinarene cavitands can target lower-molecular-weight MPs, including halomethane disinfection byproducts and industrial solvents, that are not bound strongly by β-cyclodextrins. These materials demonstrate the potential of expanding the library of polymers based on molecular receptors. Overall, these emerging adsorbents show promise for the removal of legacy and emerging MPs from water, as well as the ability to rationally tune the adsorbent's structure to target the most persistent and toxic MPs.

The third route: Using extreme decentralization to create resilient urban water systems

For much of the world's urban population, centralized treatment plants and pipe networks built in the nineteenth and twentieth centuries provide homes with water and a means of disposing of the resulting wastewater. Due to the real or perceived inability of existing systems to deliver safe and palatable water, many users apply additional treatment prior to consumption. Where piped water supply is lacking, drinking water is obtained through water vendors at considerable cost. Despite economic inefficiencies and public health risks inherent in these two water supply systems, the high sunk costs of existing water infrastructure along with low returns on investment and the inflexible nature of the institutions involved in water provision have slowed down the diffusion of alternative approaches that may prove to be less expensive, more adaptable and safer than the current system. We advocate a third, complementary route: household-based personalized water systems. Initially, relatively affluent people expecting more functionality and sustainability from water systems will invest in personalized water systems that allow them to tailor their water to their personal preferences. This approach will tap into the tremendous creativity-base of individual users and entrepreneurs, facilitating the type of co-creation that accelerated the rapid development of consumer electronics. Competition among manufacturers and economies of scale that accrue as these systems become more popular will lead to rapid innovation that drives down costs, improves performance and expands access. These solutions complement emerging approaches for sanitation and resource recovery that do not rely upon sewers for the management of human waste.

Trends in Store-Level Sales of Sugary Beverages and Water in the U.S., 2006-2015

INTRODUCTION

Previous research on sugar-sweetened beverage trends has focused on self-reported consumption from surveys. Few studies used objective store sales or explored differences by area-level demographics and store type.

METHODS

The average volume of beverages sold per store per 3-digit zoning improvement plan code from 2006 to 2015 was calculated using national Nielsen Retail Scanner point-of-sale data from 24,240 stores. A multilevel regression model analyzed annual trends, with random intercepts for state and separate models for beverage type (regular soda, no/low-calorie soda, other sugary drinks, 100% fruit juice, bottled water). Differences by store type (convenience, supermarkets, drug stores, mass merchandisers) and area-level demographics (categorized as tertiles) were examined. Data were analyzed in 2019.

RESULTS

The model-based estimates indicated that sales of regular soda (-11.8%), no/low-calorie soda (-19.8%), and 100% fruit juice (-31.9%) decreased over time, whereas sales of bottled water (+34.4%) increased and sales of other sugary drinks remained stable (+2.4%). Decreases in sugar-sweetened beverage sales were largely concentrated in supermarkets and larger in areas with high income and education levels and a high percentage of black and Hispanic people. There were also relatively larger increases in bottled water sales in states located in the South and Midwest.

CONCLUSIONS

The finding that sales of sugar-sweetened beverages decreased over time, whereas sales of bottled water increased is encouraging because sugar-sweetened beverage consumption is linked to obesity and other chronic conditions. This study provides a novel, rigorous assessment of U.S. beverage sales trends and differences by community and store characteristics.

Perspectives from the Society for Pediatric Research: contaminants of water and children's health: Can we do better?

Children are uniquely susceptible to the health consequences of water contamination. In this review, we summarize the existing, robust literature supporting the importance of examining specific water contaminants (i.e., lead, pesticides, nitrates, arsenic, perchlorate) and the routes of contamination in the United States and globally. We also discuss the health effects of exposure to contaminated water and significant disparities related to access to clean water. Lastly, we offer strategies for prevention and intervention-including those focused on the individual patient level-and review the current US policy framework pertaining to regulation of these toxicants. IMPACT: A key message in this article is that exposure to water contaminants have serious and long-lasting consequences on children's health. This review summarizes current existing literature and adds policy recommendations supporting clean water for children. Information from this review has two potential impacts: Guide health professionals in screening and/or treating children's health problems resulting from water contaminant exposure. Guide policy makers in using evidence-based approaches to improve water quality and clean water access.

Drinking Water in the United States: Implications of Water Safety, Access, and Consumption

Recent water quality crises in the United States, and recognition of the health importance of drinking water in lieu of sugar-sweetened beverages, have raised interest in water safety, access, and consumption. This review uses a socioecological lens to examine these topics across the life course. We review water intakes in the United States relative to requirements, including variation by age and race/ethnicity. We describe US regulations that seek to ensure that drinking water is safe to consume for most Americans and discuss strategies to reduce drinking water exposure to lead, a high-profile regulated drinking water contaminant. We discuss programs, policies, and environmental interventions that foster effective drinking water access, a concept that encompasses key elements needed to improve water intake. We conclude with recommendations for research, policies, regulations, and practices needed to ensure optimal water intake by all in the United States and elsewhere.

Neonatal Lead (Pb) Exposure and DNA Methylation Profiles in Dried Bloodspots

Lead (Pb) exposure remains a major concern in the United States (US) and around the world, even following the removal of Pb from gasoline and other products. Environmental Pb exposures from aging infrastructure and housing stock are of particular concern to pregnant women, children, and other vulnerable populations. Exposures during sensitive periods of development are known to influence epigenetic modifications which are thought to be one mechanism of the Developmental Origins of Health and Disease (DOHaD) paradigm. To gain insights into early life Pb exposure-induced health risks, we leveraged neonatal dried bloodspots in a cohort of children from Michigan, US to examine associations between blood Pb levels and concomitant DNA methylation profiles (n = 96). DNA methylation analysis was conducted via the Infinium MethylationEPIC array and Pb levels were assessed via high resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). While at-birth Pb exposure levels were relatively low (average 0.78 µg/dL, maximum of 5.27 ug/dL), we identified associations between DNA methylation and Pb at 33 CpG sites, with the majority (82%) exhibiting reduced methylation with increasing Pb exposure (q < 0.2). Biological pathways related to development and neurological function were enriched amongst top differentially methylated genes by p-value. In addition to increases/decreases in methylation, we also demonstrate that Pb exposure is related to increased variability in DNA methylation at 16 CpG sites. More work is needed to assess the accuracy and precision of metals assessment using bloodspots, but this study highlights the utility of this unique resource to enhance environmental epigenetics research around the world.

Chip-based ion chromatography (chip-IC) with a sensitive five-electrode conductivity detector for the simultaneous detection of multiple ions in drinking water

The emerging need for accurate, efficient, inexpensive, and multiparameter monitoring of water quality has led to interest in the miniaturization of benchtop chromatography systems. This paper reports a chip-based ion chromatography (chip-IC) system in which the microvalves, sample channel, packed column, and conductivity detector are all integrated on a polymethylmethacrylate (PMMA) chip. A laser-based bonding technique was developed to guarantee simultaneous robust sealing between the homogeneous and heterogeneous interfaces. A five-electrode-based conductivity detector was presented to improve the sensitivity for nonsuppressed anion detection. Common anions (F^-, Cl^-, NO₃ ^-, and SO₄ ^2-) were separated in less than 8 min, and a detection limit (LOD) of 0.6 mg L^-1 was achieved for SO₄ ^2-. Tap water was also analyzed using the proposed chip-IC system, and the relative deviations of the quantified concentration were less than 10% when compared with that a commercial IC system.

Exploring the Mechanisms of Selectivity for Environmentally Significant Oxo-Anion Removal during Water Treatment: A Review of Common Competing Oxo-Anions and Tools for Quantifying Selective Adsorption

Development of novel adsorbents often neglects the competitive adsorption between co-occurring oxo-anions, overestimating realistic pollutant removal potentials, and overlooking the need to improve selectivity of materials. This critical review focuses on adsorptive competition between commonly co-occurring oxo-anions in water and mechanistic approaches for the design and development of selective adsorbents. Six "target" oxo-anion pollutants (arsenate, arsenite, selenate, selenite, chromate, and perchlorate) were selected for study. Five "competing" co-occurring oxo-anions (phosphate, sulfate, bicarbonate, silicate, and nitrate) were selected due to their potential to compete with target oxo-anions for sorption sites resulting in decreased removal of the target oxo-anions. First, a comprehensive review of competition between target and competitor oxo-anions to sorb on commonly used, nonselective, metal (hydr)oxide materials is presented, and the strength of competition between each target and competitive oxo-anion pair is classified. This is followed by a critical discussion of the different equations and models used to quantify selectivity. Next, four mechanisms that have been successfully utilized in the development of selective adsorbents are reviewed: variation in surface complexation, Lewis acid/base hardness, steric hindrance, and electrostatic interactions. For each mechanism, the oxo-anions, both target and competitors, are ranked in terms of adsorptive attraction and technologies that exploit this mechanism are reviewed. Third, given the significant effort to evaluate these systems empirically, the potential to use computational quantum techniques, such as density functional theory (DFT), for modeling and prediction is explored. Finally, areas within the field of selective adsorption requiring further research are detailed with guidance on priorities for screening and defining selective adsorbents.

Patterns and predictions of drinking water nitrate violations across the conterminous United States

Excess nitrate in drinking water is a human health concern, especially for young children. Public drinking water systems in violation of the 10 mg nitrate-N/L maximum contaminant level (MCL) must be reported in EPA's Safe Drinking Water Information System (SDWIS). We used SDWIS data with random forest modeling to examine the drivers of nitrate violations across the conterminous U.S. and to predict where public water systems are at risk of exceeding the nitrate MCL. As explanatory variables, we used land cover, nitrogen inputs, soil/hydrogeology, and climate variables. While we looked at the role of nitrate treatment in separate analyses, we did not include treatment as a factor in the final models, due to incomplete information in SDWIS. For groundwater (GW) systems, a classification model correctly classified 79% of catchments in violation and a regression model explained 43% of the variation in nitrate concentrations above the MCL. The most important variables in the GW classification model were % cropland, agricultural drainage, irrigation-to-precipitation ratio, nitrogen surplus, and surplus precipitation. Regions predicted to have risk for nitrate violations in GW were the Central California Valley, parts of Washington, Idaho, the Great Plains, Piedmont of Pennsylvania and Coastal Plains of Delaware, and regions of Wisconsin, Iowa, and Minnesota. For surface water (SW) systems, a classification model correctly classified 90% of catchments and a regression model explained 52% of the variation in nitrate concentration. The variables most important for the SW classification model were largely hydroclimatic variables including surplus precipitation, irrigation-to-precipitation ratio, and % shrubland. Areas at greatest risk for SW nitrate violations were generally in the non-mountainous west and southwest. Identifying the areas with possible risk for future violations and potential drivers of nitrate violations across U.S. can inform decisions on how source water protection and other management options could best protect drinking water.

Springing for Safe Water: Drinking Water Quality and Source Selection in Central Appalachian Communities

Issues surrounding water infrastructure, access, and quality are well documented in the Central Appalachian region of the United States. Even in cases where residents have in-home piped point-of-use (POU) water, some rely on alternative drinking water sources for daily needs—including water collection from roadside springs. This effort aims to better understand and document spring usage in this region by identifying the factors that influence drinking water source selection and comparing household and spring water quality to Safe Drinking Water Act (SDWA) health-based and aesthetic contaminant recommendations. Households were recruited from communities surrounding known springs in three states (Kentucky, Virginia, and West Virginia). First- and second-draw, in-home POU tap water samples were collected from participating households and compared to samples collected from local springs on the same day. Samples were analyzed for fecal indicator bacteria and inorganic ions. Study participants completed surveys to document perceptions of household drinking water and typical usage. The majority of survey participants (82.6%) did not trust their home tap water due to aesthetic issues. Water quality results suggested that fecal indicator bacteria were more common in spring water, while several metallic ions were recovered in higher concentrations from household samples. These observations highlight that health risks and perceptions may be different between sources.

Spatiotemporal trends of recovery from lead contamination in Flint, MI as revealed by crowdsourced water sampling

In the aftermath of the lead contamination crisis that plagued the water system in Flint, MI, more than 35,000 water samples were collected from the city's premises. The majority of these samples (>85%) were collected through a voluntary crowdsourced sampling campaign. The samples were analyzed for lead and copper concentrations by the Michigan Department of Environmental Quality (MDEQ). In this study, the crowdsourced sampling data was analyzed by means of spatial autocorrelation analysis to reveal the locations of statistically significant hotspot regions of high water lead levels (WLLs), and to track the spatiotemporal evolution of WLLs as the system recovered from lead contamination. The results showed that hotspot regions that experienced high WLLs were consistent with the areas where lead service line (LSL) density was the highest. Additionally, galvanized service lines and other lead-containing plumbing components could have also contributed to lead release in hotspot regions. The temporal trend exhibited by the crowdsourced sampling data did not reflect a consistent decrease in WLLs despite the interventions implemented by MDEQ and EPA. Instead, sampled WLLs remained high for several months after boosting the orthophosphate dose and launching a city-wide residential flushing campaign. The findings of this study suggest that this could be partially attributed to disproportionate sampling from premises in hotspot regions of high WLLs and LSL density.

Genome-scale transcriptional dynamics and environmental biosensing

Genome-scale technologies have enabled mapping of the complex molecular networks that govern cellular behavior. An emerging theme in the analyses of these networks is that cells use many layers of regulatory feedback to constantly assess and precisely react to their environment. The importance of complex feedback in controlling the real-time response to external stimuli has led to a need for the next generation of cell-based technologies that enable both the collection and analysis of high-throughput temporal data. Toward this end, we have developed a microfluidic platform capable of monitoring temporal gene expression from over 2,000 promoters. By coupling the "Dynomics" platform with deep neural network (DNN) and associated explainable artificial intelligence (XAI) algorithms, we show how machine learning can be harnessed to assess patterns in transcriptional data on a genome scale and identify which genes contribute to these patterns. Furthermore, we demonstrate the utility of the Dynomics platform as a field-deployable real-time biosensor through prediction of the presence of heavy metals in urban water and mine spill samples, based on the the dynamic transcription profiles of 1,807 unique Escherichia coli promoters.

Complexation by Organic Matter Controls Uranium Mobility in Anoxic Sediments

Uranium contamination threatens the availability of safe and clean drinking water globally. This toxic element occurs both naturally and as a result of mining and ore-processing in alluvial sediments, where it accumulates as tetravalent U [U(IV)], a form once considered largely immobile. Changing hydrologic and geochemical conditions cause U to be released into groundwater. Knowledge of the chemical form(s) of U(IV) is essential to understand the release mechanism, yet the relevant U(IV) species are poorly characterized. There is growing belief that natural organic matter (OM) binds U(IV) and mediates its fate in the subsurface. In this work, we combined nanoscale imaging (nano secondary ion mass spectrometry and scanning transmission X-ray microscopy) with a density-based fractionation approach to physically and microscopically isolate organic and mineral matter from alluvial sediments contaminated with uranium. We identified two populations of U (dominantly +IV) in anoxic sediments. Uranium was retained on OM and adsorbed to particulate organic carbon, comprising both microbial and plant material. Surprisingly, U was also adsorbed to clay minerals and OM-coated clay minerals. The dominance of OM-associated U provides a framework to understand U mobility in the shallow subsurface, and, in particular, emphasizes roles for desorption and colloid formation in its mobilization.

Environmental Health Practice Challenges and Research Needs for U.S. Health Departments

BACKGROUND

Environmental health (EH) professionals, one of the largest segments of the public health workforce, are responsible for delivery of essential environmental public health services. The challenges facing these professionals and research needs to improve EH practice are not fully understood, but 26% of EH professionals working in health departments of the United States plan to retire in 5 y, while only 6% of public health students are currently pursuing EH concentrations.

OBJECTIVES

A groundbreaking initiative was recently launched to understand EH practice in health departments of the United States. This commentary article aims to identify priority EH practice challenges and related research needs for health departments.

METHODS

A horizon scanning approach was conducted in which challenges facing EH professionals were provided by 1,736 respondents working at health departments who responded to a web-based survey fielded in November 2017. Thematic analyses of the responses and determining the frequency at which respondents reported specific issues and opportunities identified primary EH topic areas. These topic areas and related issues informed focus group discussions at an in-person workshop held in Anaheim, California. The purpose of the in-person workshop was to engage each of the topic areas and issues, through facilitated focus groups, leading to the formation of four to five related problem statements for each EH topic.

DISCUSSION

EH professionals are strategically positioned to diagnose, intervene, and prevent public health threats. Focus group engagement resulted in 29 priority problem statements partitioned among 6 EH topic areas: a) drinking water quality, b) wastewater management, c) healthy homes, d) food safety, e) vectors and public health pests, and f) emerging issues. This commentary article identifies priority challenges and related research needs to catalyze effective delivery of essential environmental public health services for common EH program areas in health departments. An unprecedented initiative to revitalize EH practice with timely and strategic recommendations for student and professional training, nontraditional partnerships, and basic and translational research activities is recommended. https://doi.org/10.1289/EHP5161.

Electrocoagulation as a Pretreatment for Electroxidation of E. coli

Insufficient funding and operator training, logistics of chemical transport, and variable source water quality can pose challenges for small drinking water treatment systems. Portable, robust electrochemical processes may offer a strategy to address these challenges. In this study, electrocoagulation (EC) and electrooxidation (EO) were investigated using two model surface waters and two model groundwaters to determine the efficacy of sequential EC-EO for mitigating Escherichia coli. EO alone (1.67 mA/cm2, 1 min) provided 0.03 to 3.9 logs mitigation in the four model waters. EC alone (10 mA/cm2, 5 min) achieved ≥1 log E. coli mitigation in all model waters. Sequential EC-EO did not achieve greater mitigation than EC alone. To enhance removal of natural organic matter, the initial pH was decreased. Lower initial pH (pH 5–6) improved E. coli mitigation during both stages of EC-EO. EC-EO also had slightly greater E. coli mitigation than EC alone at lower pH. However, EO alone provided more energy efficient E. coli mitigation than either EC or EC-EO.

Mitigating the risk of atrazine exposure: Identifying hot spots and hot times in surface waters across Nebraska, USA

Atrazine, one of the most widely used herbicides in the world, threatens human health along with terrestrial and aquatic biota. Recent reports have found atrazine in drinking water to be associated with increased birth defects and incidences of Non-Hodgkin's Lymphoma, with higher levels of significance from exposure to both atrazine and nitrate-N. The Midwest region of the United States, which includes Nebraska, is one of the leading regions for high nitrate-N concentrations and agrochemicals, including atrazine, in surface waters. Therefore, the objective of this study was to provide a case study for completing an environmental risk analysis for the potential exposure of atrazine and nitrate-N to ecosystems and humans through interaction with surface waters using two approaches: (1) Identify watersheds across Nebraska that were at risk for exceeding atrazine and nitrate-N maximum contaminant limits (MCLs) in surface water; and (2) Determine the specific times of year where risks were greatest. Factors were then analyzed using Geographic Information System (GIS) software to identify areas of high risk. Impairments for both nitrate-N and atrazine in the surface water were found predominately during the early growing season in the southeastern region of Nebraska, in watershed areas with the highest amount of corn production and annual precipitation. Further, the methodology developed in this study has the potential for application in regions with higher dependency on surface water to determine multiple agrochemical load influxes from upstream regions and evaluate other surface water contaminants during the same time periods.

THE ENVIRONMENTAL AND SAFETY PERFORMANCE OF GAS UTILITIES IN THE UNITED STATES

The performance of energy service providers has important environmental and safety consequences in local communities. This paper uses a novel dataset compiled from operator reports and infrastructure monitoring data obtained from three different US federal agencies to assess the performance of retail gas utilities nationwide in terms of addressing gas leaks and minimizing leak volumes. Our panel data set includes yearly observations for 727 retail gas utilities from 2009 to 2017. We show that safety hazards and environmental costs of gas leaks are widespread across providers that vary in terms of ownership, size, and region. We then use series of Bayesian hierarchical models to regress four outcome variables--hazardous leaks, end-year unfixed leaks, total gas volume leaked, and significant incidents--on infrastructure conditions, regional service context, and socio-economic service population characteristics. Unlike what is observed in other critical infrastructure cases such as drinking water, socioeconomic conditions are not strongly predictive of service outcomes. Public utilities exhibit better environmental performance on average, and no difference in maintenance backlogs. Because the environmental costs of poor performance--primarily in terms of methane greenhouse gas emissions--are predominantly social, policy tools such as consolidation and privatization are unlikely to improve environmental outcomes.

Arsenic Drinking Water Violations Decreased across the United States Following Revision of the Maximum Contaminant Level

Arsenic poses a threat to public health due to widespread environmental prevalence and known carcinogenic effects. In 2001, the US EPA published the Final Arsenic Rule (FAR) for public drinking water, reducing the maximum contaminant level (MCL) from 50 to 10 μg/L. We investigated impacts of the FAR on drinking water violations temporally and geographically using the Safe Drinking Water Information System. Violations exceeding the MCL and the population served by violating systems were analyzed across the conterminous US from 2006 (onset of FAR enforcement) to 2017. The percentage of public water system violations declined from 1.3% in 2008 to 0.55% in 2017 (p < 0.001, slope = -0.070), and the population served decreased by over 1 million (p < 0.001, slope = -106 886). Geographical analysis demonstrated higher mean violations and populations served in certain counties rather than evenly distributed across states. The decline in violations is likely due to the adoption of documented and undocumented treatment methods and possibly from reduced environmental releases. Considering other studies that have shown decreased urinary arsenic levels in the population served by public water systems since the new standard, it may be inferred that the FAR is facilitating the reduction of arsenic exposure in the US.

Detecting community response to water quality violations using bottled water sales

Drinking-water contaminants pose a risk to public health. When confronted with elevated levels of contaminants, individuals can take actions to reduce exposure. Yet, few studies address averting behavior due to impaired water, particularly in high-income countries. This is a problem of national interest, given that 9 million to 45 million people have been affected by water quality violations in each of the past 34 years. No national analysis has focused on the extent to which communities reduce exposure to contaminated drinking water. Here, we present an assessment that sheds light on how communities across the United States respond to violations of the Safe Drinking Water Act, using consumer purchases of bottled water. This study provides insight into how averting behavior differs across violation types and community demographics. We estimate the change in sales due to water quality violations, using a panel dataset of weekly sales and violation records in 2,151 counties from 2006 to 2015. Critical findings show that violations which pose an immediate health risk are associated with a 14% increase in bottled water sales. Generally, greater averting action is taken against contaminants that might pose a greater perceived health risk and that require more immediate public notification. Rural, low-income communities do not take significant averting action for elevated levels of nitrate, yet experience a higher prevalence of nitrate violations. Findings can inform improvements in public notification and targeting of technical assistance from state regulators and public health agencies in order to reduce community exposure to contaminants.

Cumulative risk analysis of carcinogenic contaminants in United States drinking water

Cumulative risk analysis of contaminant occurrence in United States drinking water for the period of 2010-2017 indicates that over 100,000 lifetime cancer cases could be due to carcinogenic chemicals in tap water. The majority of this risk is due to the presence of arsenic, disinfection byproducts and radioactive contaminants. For different states within the U.S., cumulative cancer risk for drinking water contaminants ranges between 1 × 10^-4 and 1 × 10^-3, similar to the range of cumulative cancer risks reported for air pollutants. Overall, national attributable risk due to tap water contaminants is approximately 4 × 10^-4, which is two orders of magnitude higher than the de minimus cancer risk of one-in-a-million. Thus, decreasing the levels of chemical contaminants in drinking water represents an important opportunity for protecting public health.

Extreme Precipitation, Public Health Emergencies, and Safe Drinking Water in the USA

PURPOSE OF REVIEW

This review examines the effectiveness of drinking water regulations to inform public health during extreme precipitation events. This paper estimates the vulnerability of specific populations to flooding in their public water system, reviews the literature linking precipitation to waterborne outbreaks, examines the role that Safe Drinking Water Act and Public Notification (PN) Rule have in public health emergencies, and reviews the effectiveness of the PN Rule during the 2017 Hurricane Maria in Puerto Rico.

RECENT FINDINGS

Public water systems in large metropolitan areas have substantial portions of their customer base at risk for a waterborne outbreak during a flooding event. The PN Rule are ambiguous for who is responsible for declaring a "waterborne emergency" following a natural disaster like Hurricane Maria. Revisions to the current PN Rule that mandate public notification and water quality sampling during extreme precipitation events are necessary to ensure the public is aware of their drinking water quality following these events.

Water contaminant levels interact with parenting environment to predict development of depressive symptoms in adolescents

Contaminants in drinking water, such as lead, nitrate, and arsenic, have been linked to negative physical health outcomes. We know less, however, about whether such pollutants also predict mental health problems and, if so, the conditions under which such effects are strongest. In this longitudinal study, we examined whether drinking water contaminants interact with negative family environments (parental psychological control) to predict changes in depressive symptoms in 110 adolescents-a developmental period when symptoms often first emerge. We found that for adolescents in psychologically controlling families, levels of drinking water contaminants prospectively predicted depressive symptoms 2 years later; this effect was not present in adolescents in non-controlling families. Importantly, these associations were not accounted for by family- or community-level socioeconomic resources, demographic features, or by the adolescents' stress exposure. These findings highlight the interplay of physical and psychological environments in influencing depressive symptoms in adolescents. A video abstract of this article can be viewed at https://youtu.be/thBV-DwnGcY.

Catalytic Converters for Water Treatment

Fresh water demand is driven by human consumption, agricultural irrigation, and industrial usage and continues to increase along with the global population. Improved methods to inexpensively and sustainably clean water unfit for human consumption are desired, particularly at remote or rural locations. Heterogeneous catalysts offer the opportunity to directly convert toxic molecules in water to nontoxic products. Heterogeneous catalytic reaction processes may bring to mind large-scale industrial production of chemicals, but they can also be used at the small scale, like catalytic converters used in cars to break down gaseous pollutants from fuel combustion. Catalytic processes may be a competitive alternative to conventional water treatment technologies. They have much faster kinetics and are less operationally sensitive than current bioremediation-based methods. Unlike other conventional water treatment technologies (i.e., ion exchange, reverse osmosis, activated carbon filtration), they do not transfer contaminants into separate, more concentrated waste streams. In this Account, we review our efforts on the development of heterogeneous catalysts as advanced reduction technologies to treat toxic water contaminants such as chlorinated organics and nitrates. Fundamental understanding of the underlying chemistry of catalytic materials can inform the design of superior catalytic materials. We discuss the impact of the catalytic structure (i.e., the arrangement of metal atoms on the catalyst surface) on the catalyst activity and selectivity for these aqueous reactions. To explore these aspects, we used model metal-on-metal nanoparticle catalysts along with state-of-the-art in situ spectroscopic techniques and density functional theory calculations to deduce the catalyst surface structure and how it affects the reaction pathways and hence the activity and selectivity. We also discuss recent developments in photocatalysis and electrocatalysis for the treatment of nitrates, touching on fundamentals and surface reaction mechanisms. Finally, we note that despite over 20 years of growing research into heterogeneous catalytic systems for water contaminants, only a few pilot-scale studies have been conducted, with no large-scale implementation to date. We conceive of modular, on- or off-grid catalytic units that treat drinking water at the household tap, at a community well, or for larger-scale reuse of agricultural runoff. We discuss how these may be enhanced by combination with photocatalytic or electrocatalytic processes and how these reductive catalytic modules (catalytic converters for water) can be coupled with other modules for the removal of potential water contaminants.

Comparative evaluation of risk management frameworks for U.S. source waters

The U.S. Safe Drinking Water Act required states to develop source water assessment programs identifying existing and potential contamination sources; however, comprehensive risk prioritization and management approaches for surface water supplies have seen limited application. This participatory study assessed which permutation(s) of risk management frameworks and tools might benefit U.S. utilities by combining a literature review with external utility interviews. Qualitative data provided a basis for categorical assignments of goodness of fit with each of 24 framework evaluation criteria across five categories. Weighted integration using stakeholder input provided a relative ranking of applicability, later validated at a decision-making workshop. Hybridization of the American National Standards Institute/American Water Works Association (ANSI/AWWA G300) source water protection standard and World Health Organization Water Safety Plan guidance was recommended to develop a comprehensive risk management approach for U.S. source waters. Cost-benefit components of other guidance materials were recommended to incorporate financial considerations into risk ranking and mitigation decisions.

Reconnaissance of Mixed Organic and Inorganic Chemicals in Private and Public Supply Tapwaters at Selected Residential and Workplace Sites in the United States

Safe drinking water at the point-of-use (tapwater, TW) is a United States public health priority. Multiple lines of evidence were used to evaluate potential human health concerns of 482 organics and 19 inorganics in TW from 13 (7 public supply, 6 private well self-supply) home and 12 (public supply) workplace locations in 11 states. Only uranium (61.9 μg L-1, private well) exceeded a National Primary Drinking Water Regulation maximum contaminant level (MCL: 30 μg L-1). Lead was detected in 23 samples (MCL goal: zero). Seventy-five organics were detected at least once, with median detections of 5 and 17 compounds in self-supply and public supply samples, respectively (corresponding maxima: 12 and 29). Disinfection byproducts predominated in public supply samples, comprising 21% of all detected and 6 of the 10 most frequently detected. Chemicals designed to be bioactive (26 pesticides, 10 pharmaceuticals) comprised 48% of detected organics. Site-specific cumulative exposure-activity ratios (∑EAR) were calculated for the 36 detected organics with ToxCast data. Because these detections are fractional indicators of a largely uncharacterized contaminant space, ∑EAR in excess of 0.001 and 0.01 in 74 and 26% of public supply samples, respectively, provide an argument for prioritized assessment of cumulative effects to vulnerable populations from trace-level TW exposures.

Drinking water in West Virginia (USA): tap water or bottled water - what is the right choice for college students?

West Virginia has had a history of water quality issues. In parallel, the world is facing a plastic pollution crisis. In order to better understand behavioral responses to perceived water quality, a survey was conducted at a major research university to ask participants about water quality perceptions and drinking water behaviors. A total of 4,188 students completed the survey during the Spring 2017 semester. Logistic regression analyses were used to predict behaviors. Results indicated that a third of the student population primarily used bottled water for drinking purposes at home, while 39% used a filter at home and 26% drank water directly from the tap. On campus, bottled water use was reported by 36% of the students, water fountain use represented 31%, and 29% of the students brought their own water with reusable cups/bottles. Health risk perceptions, organoleptic perceptions (i.e., taste, odor, color), and environmental concern were predictors of the different behaviors. Students originally from West Virginia had a higher propensity of using bottled water. We argue that bottled water consumption should be reduced in areas where water quality is not an issue. In this sense, there is a need for education among the student population in West Virginia.

Drinking Water Violations and Environmental Justice in the United States, 2011-2015

OBJECTIVES

To assess the extent to which drinking water violations in the United States differed on the basis of county race/ethnicity and socioeconomic status using the primary county served by the community water system (CWS) as the unit of analysis and to determine whether counties with higher proportions of underrepresented groups were disproportionately burdened with repeat violations.

METHODS

We used multivariable logistic regression to calculate odds ratios of contextual environmental justice covariates associated with initial and repeat drinking water violations. We obtained violations from the federal Safe Drinking Water Information System. Results were nonstratified and stratified on the basis of population size served by the CWS.

RESULTS

Stratified multivariable logistic regression results revealed previously unobservable patterns in nonstratified findings. Minorities face significant challenges, including exposure to poor water quality. The most notable differences in both initial and repeat violations that we observed were among CWSs that serve large populations. Our most consistent finding was the positive association of initial and repeat violations with the proportion of those who were uninsured, irrespective of stratification.

CONCLUSIONS

Greater efforts are needed to ensure that counties with higher proportions of minorities, uninsured households, and low-income households have access to safe drinking water, irrespective of the size of population served by the CWS.

Low risk posed by engineered and incidental nanoparticles in drinking water

Natural nanoparticles (NNPs) in rivers, lakes, oceans and ground water predate humans, but engineered nanoparticles (ENPs) are emerging as potential pollutants due to increasing regulatory and public perception concerns. This Review contrasts the sources, composition and potential occurrence of NNPs (for example, two-dimensional clays, multifunctional viruses and metal oxides) and ENPs in surface water, after centralized drinking water treatment, and in tap water. While analytical detection challenges exist, ENPs are currently orders of magnitude less common than NNPs in waters that flow into drinking water treatment plants. Because such plants are designed to remove small-sized NNPs, they are also very good at removing ENPs. Consequently, ENP concentrations in tap water are extremely low and pose low risk during ingestion. However, after leaving drinking water treatment plants, corrosion by-products released from distribution pipes or in-home premise plumbing can release incidental nanoparticles into tap water. The occurrence and toxicity of incidental nanoparticles, rather than ENPs, should therefore be the focus of future research.