Improved Decision Making for Water Lead Testing in U.S. Child Care Facilities Using Machine-Learned Bayesian Networks.

Tap water lead testing programs in the U.S. need improved methods for identifying high-risk facilities to optimize limited resources. In this study, machine-learned Bayesian network (BN) models were used to predict building-wide water lead risk in over 4,000 child care facilities in North Carolina according to maximum and 90th percentile lead levels from water lead concentrations at 22,943 taps. The performance of the BN models was compared to common alternative risk factors, or heuristics, used to inform water lead testing programs among child care facilities including building age, water source, and Head Start program status. The BN models identified a range of variables associated with building-wide water lead, with facilities that serve low-income families, rely on groundwater, and have more taps exhibiting greater risk. Models predicting the probability of a single tap exceeding each target concentration performed better than models predicting facilities with clustered high-risk taps. The BN models' Fß-scores outperformed each of the alternative heuristics by 118-213%. This represents up to a 60% increase in the number of high-risk facilities that could be identified and up to a 49% decrease in the number of samples that would need to be collected by using BN model-informed sampling compared to using simple heuristics. Overall, this study demonstrates the value of machine-learning approaches for identifying high water lead risk that could improve lead testing programs nationwide.

The effects of racism, social exclusion, and discrimination on achieving universal safe water and sanitation in high-income countries.

Drinking water and sanitation services in high-income countries typically bring widespread health and other benefits to their populations. Yet gaps in this essential public health infrastructure persist, driven by structural inequalities, racism, poverty, housing instability, migration, climate change, insufficient continued investment, and poor planning. Although the burden of disease attributable to these gaps is mostly uncharacterised in high-income settings, case studies from marginalised communities and data from targeted studies of microbial and chemical contaminants underscore the need for continued investment to realise the human rights to water and sanitation. Delivering on these rights requires: applying a systems approach to the problems; accessible, disaggregated data; new approaches to service provision that centre communities and groups without consistent access; and actionable policies that recognise safe water and sanitation provision as an obligation of government, regardless of factors such as race, ethnicity, gender, ability to pay, citizenship status, disability, land tenure, or property rights.

Patterns of Children's Blood Lead Screening and Blood Lead Levels in North Carolina, 2011-2018-Who Is Tested, Who Is Missed?

BACKGROUND: No safe level of lead in blood has been identified. Blood lead testing is required for children on Medicaid, but it is at the discretion of providers and parents for others. Elevated blood lead levels (EBLLs) cannot be identified in children who are not tested. OBJECTIVES: The aims of this research were to identify determinants of lead testing and EBLLs among North Carolina children and estimate the number of additional children with EBLLs among those not tested. METHODS: We linked geocoded North Carolina birth certificates from 2011-2016 to 2010 U.S. Census data and North Carolina blood lead test results from 2011-2018. We estimated the probability of being screened for lead and created inverse probability (IP) of testing weights. We evaluated the risk of an EBLL of ≥3µg/dL at <30 months of age, conditional on characteristics at birth, using generalized linear models and then applied IP weights to account for missing blood lead results among unscreened children. We estimated the number of additional children with EBLLs of all North Carolina children using the IP-weighted population and bootstrapping to produce 95% credible intervals (CrI). RESULTS: Mothers of the 63.5% of children (402,002 of 633,159) linked to a blood lead test result were disproportionately young, Hispanic, Black, American Indian, or on Medicaid. In full models, maternal age ≤20y [risk ratio (RR)=1.10; 95% confidence interval (CI): 1.13, 1.20] or smoking (RR=1.14; 95% CI: 1.12, 1.17); proximity to a major roadway (RR=1.10; 95% CI: 1.05, 1.15); proximity to a lead-releasing Toxics Release Inventory site (RR=1.08; 95% CI: 1.03, 1.14) or a National Emissions Inventory site (RR=1.11; 95% CI: 1.07, 1.14); and living in neighborhoods with more housing built before 1950 (RR=1.10; 95% CI: 1.05, 1.14) or before 1940 (RR=1.18; 95% CI: 1.11, 1.25) or more vacant housing (RR=1.14; 95% CI: 1.11, 1.17) were associated with an increased risk of EBLL, whereas overlap with a public water service system was associated with a decreased risk of EBLL (RR=0.85; 95% CI: 0.83, 0.87). Children of Black mothers were no more likely than children of White mothers to have EBLLs (RR=0.98; 95% CI: 0.96, 1.01). Complete blood lead screening in 2011-2018 may have identified an additional 17,543 (95% CrI: 17,462, 17,650) children with EBLLs ≥3µg/dL. DISCUSSION: Our results indicate that current North Carolina lead screening strategies fail to identify over 30% (17,543 of 57,398) of children with subclinical lead poisoning and that accounting for characteristics at birth alters the conclusions about racial disparities in children's EBLLs. https://doi.org/10.1289/EHP10335.

A new approach to a legacy concern: Evaluating machine-learned Bayesian networks to predict childhood lead exposure risk from community water systems.

Lead in drinking water continues to put children at risk of irreversible neurological impairment. Understanding drinking water system characteristics that influence blood lead levels is needed to prevent ongoing exposures. This study sought to assess the relationship between children's blood lead levels and drinking water system characteristics using machine-learned Bayesian networks. Blood lead records from 2003 to 2017 for 40,742 children in Wake County, North Carolina were matched with the characteristics of 178 community water systems and sociodemographic characteristics of each child's neighborhood. Bayesian networks were machine-learned to evaluate the drinking water variables associated with blood lead levels ≥2 µg/dL and ≥5 µg/dL. The model was used to predict geographic areas and water utilities with increased lead exposure risk. Drinking water characteristics were not significantly associated with children's blood lead levels ≥5 µg/dL but were important predictors of blood lead levels ≥2 µg/dL. Whether 10% of water samples exceeded 2 ppb of lead in the most recent year prior to the blood test was the most important water system predictor and increased the risk of blood lead levels ≥2 µg/dL by 42%. The model achieved an area under the receiver operating characteristic curve of 0.792 (±0.8%) during ten-fold cross validation, indicating good predictive performance. Water system characteristics may thus be used to predict areas that are at risk of higher blood lead levels. Current drinking water regulatory thresholds for lead may be insufficient to detect the levels in drinking water associated with children's blood lead levels.

User experience of point-of-use water treatment for private wells in North Carolina: Implications for outreach and well stewardship.

Private well users are potentially exposed to a range of chemical contaminants through their drinking water. Point-of-use (POU) water treatment represents one potential solution to reduce harmful exposures through well water, but well users frequently do not adopt household treatment even if they learn their water is contaminated. This study elucidates the experiences, perceptions, and beliefs of 17 households on private wells in North Carolina that participated in a pilot-scale POU water treatment intervention to better understand the drivers and barriers of POU treatment adoption among well users. The intervention consisted of an under-sink activated carbon block POU filter designed to remove lead and two long-chain perfluoroalkyl acids. Filter effluents and influents were tested monthly for eight months. Questionnaires administered before and after the intervention showed a significant decrease in participants' perceived vulnerability to well water contamination, with 77% feeling vulnerable to poor well water quality before, compared to 23% after the filter was installed. However, the POU filters did not fully eliminate feelings of water insecurity (for example, concerns about exposure to contaminants when bathing remained). Lack of knowledge and skills associated with installing and maintaining POU treatment were important barriers to adoption for some well users. Perceptions of POU treatment were also significantly correlated with the intent to implement other well stewardship behaviors such as well water testing. The results highlight the need for strengthened outreach and support programs that provide technical assistance, education, and financial support for households relying on private wells.

Private Well Testing in Peri-Urban African-American Communities Lacking Access to Regulated Municipal Drinking Water: A Mental Models Approach to Risk Communication.

Majority African-American neighborhoods on the edges of North Carolina municipalities are less likely than white peri-urban neighborhoods to be served by a community system regulated under the Safe Drinking Water Act. These households rely on unregulated private wells, which are at much higher risk of contamination than neighboring community water supplies. Yet, risk awareness of consuming well water is low, and no prior research has tested risk communication interventions for these communities. We present a randomized-controlled trial of an oversized postcard to promote water testing among this audience. The postcard design followed the mental models approach to risk communication. To our knowledge, this is the first U.S. randomized-controlled trial of a mailed communication to promote water testing in any audience and one of few trials of the mental models approach. We evaluated the postcard's effects on self-reported water testing with and without a free water test offer (vs. no-intervention control) via a survey mailed one month after the interventions. The combined communication and free test doubled the odds of self-reported water testing, compared to the control group (p = 0.046). It increased the odds of testing by 65%, compared to the free test alone. Recall of receiving a postcard about water testing increased the odds of self-reported testing twelve-fold (p < 0.001). Although these results suggest that targeted risk information delivered by mail can promote water testing when paired with a free test, the mechanism remains unclear. Additional research on beliefs influencing perceptions about well water may yield interventions that are even more effective.

Are carbon water filters safe for private wells? Evaluating the occurrence of microbial indicator organisms in private well water treated by point-of-use activated carbon block filters.

Point-of-use (POU) water treatment is highly relevant to private well users vulnerable to chemical contamination, but uncertainty remains around the effects of activated carbon based POU devices on the microbial quality of the treated water. In this study, under-sink activated carbon block water filters were installed in 17 homes relying on private well water in North Carolina. The influent and effluent water in each home was evaluated for bacterial and viral microbial indicator organisms monthly for five months. Multiple logistic regression was used to identify water quality and water usage variables that were significant predictors of each indicator organism occurring in the filter effluent. The odds of total coliforms occurring in the effluent decreased by 84% with each 1-log10 increase in the influent HPC (p < 0.05), suggesting a protective effect by native heterotrophic bacteria, but increased by over 50 times with low cumulative water use (p < 0.05). The filters were not protective against coliphages in the influent and viral shedding may occur after periods of increased virus concentrations in the raw well water. Specific bacteria were also found to increase in the effluent, causing a shift in the bacterial community composition, although potential opportunistic pathogens were detected in both the influent and the effluent. Overall, under normal conditions of use, the filters tested in this study did not represent a significant additional risk for well users beyond the existing exposures from undisinfected well water alone.

Impacts of Exclusion From Municipal Water Service on Water Availability: A Case Study.

Bordering the wealthy town of Apex, North Carolina, is a majority African-American neighborhood, Irongate Drive, without town water service, relying on private wells. Residents have long sought access to town water as their wells are running dry, but problems have not been systematically documented. Using a comprehensive survey and qualitative interviews, this study assesses the frequency of water shortages, uncovers the effects on daily lives, and reports on water source preferences. Surveys showed 80 percent of households experience water scarcity. Respondents reported not having enough water to flush toilets, shower, wash hands, or do laundry. Annual well maintenance costs averaged $1405; additional costs included dealing with water shortage and buying additional items to cope. More than 75 percent actively seek municipal water, and none oppose it. These results could inform assessments of impacts of water access disparities in similar peri-urban minority communities nationwide that remain excluded from nearby municipal services.

Risk Communication and Factors Influencing Private Well Testing Behavior: A Systematic Scoping Review.

Unregulated private wells may be at risk for certain types of contamination associated with adverse health effects. Well water testing is a primary method to identify such risks, although testing rates are generally low. Risk communication is used as an intervention to promote private well testing behavior; however, little is known about whether these efforts are effective as well as the mechanisms that influence effectiveness. A systematic scoping review was conducted to evaluate the current evidence base for risk communication effectiveness and factors that influence well testing behavior. The review was conducted with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) framework. Data were synthesized using a health behavior model (Health Belief Model) to identify areas amenable to intervention and factors to consider when designing risk communication interventions. We identified a significant shortage of studies examining the effectiveness of risk communication interventions targeted to well testing behavior, with only two quasi-experimental studies identified. The review also identified seventeen studies that examined or described factors relating to well testing behavior. The two empirical studies suggest risk communication methods can be successful in motivating private well owners to test their water, while the remaining studies present considerations for developing effective, community-specific content.

Relationship between race and community water and sewer service in North Carolina, USA.

Previous evidence has identified potential racial disparities in access to community water and sewer service in peri-urban areas adjacent to North Carolina municipalities. We performed the first quantitative, multi-county analysis of these disparities. Using publicly available data, we identified areas bordering municipalities and lacking community water and/or sewer service in 75 North Carolina counties. Logistic regression was performed to evaluate the relationship between race and access to service in peri-urban areas, controlling for population density, median home value, urban status, and percent white in the adjacent municipality. In the peri-urban areas analyzed, 67% of the population lacked community sewer service, and 33% lacked community water service. In areas other than those with no black residents, odds of having community water service (p<0.01) or at least one of the two services (p<0.05) were highest for census blocks with a small proportion of black residents and lowest in 100% black census blocks, though this trend did not hold for access to community sewer service alone. For example, odds of community water service were 85% higher in areas that were greater than 0% but less than 22% black than in 100% black areas (p<0.001). Peri-urban census blocks without black populations had the lowest odds of community water service, community sewer service, and at least one of the two services, but this difference was only statistically significant for sewer. Peri-urban areas lacking service with no black residents were wealthier than 100% black areas and areas with any percent black greater than 0%. Findings suggest two unserved groups of differing racial and socioeconomic status: (1) lower-income black populations potentially excluded from municipal services during the era of legal racial segregation and (2) higher-income non-black populations. Findings also suggest greater racial disparities in community water than community sewer services statewide.

Strategies to Improve Private-Well Water Quality: A North Carolina Perspective.

BACKGROUND: Evidence suggests that the 44.5 million U.S. residents drawing their drinking water from private wells face higher risks of waterborne contaminant exposure than those served by regulated community water supplies. Among U.S. states, North Carolina (N.C.) has the second-largest population relying on private wells, making it a useful microcosm to study challenges to maintaining private-well water quality. OBJECTIVES: This paper summarizes recommendations from a two-day summit to identify options to improve drinking-water quality for N.C. residents served by private wells. METHODS: The Research Triangle Environmental Health Collaborative invited 111 participants with knowledge of private-well water challenges to attend the Summit. Participants worked in small groups that focused on specific aspects and reconvened in plenary sessions to formulate consensus recommendations. DISCUSSION: Summit participants highlighted four main barriers to ensuring safe water for residents currently relying on private wells: (1) a database of private well locations is unavailable; (2) racial disparities have perpetuated reliance on private wells in some urbanized areas; (3) many private-well users lack information or resources to monitor and maintain their wells; and (4) private-well support programs are fragmented and lack sufficient resources. The Summit produced 10 consensus recommendations for ways to overcome these barriers. CONCLUSIONS: The Summit recommendations, if undertaken, could improve the health of North Carolinians facing elevated risks of exposure to waterborne contaminants because of their reliance on inadequately monitored and maintained private wells. Because many of the challenges in N.C. are common nationwide, these recommendations could serve as models for other states. https://doi.org/10.1289/EHP890.

Designing Graphs to Communicate Risks: Understanding How the Choice of Graphical Format Influences Decision Making.

Previous research suggests that the choice of graphical format for communicating risk information affects both understanding of the risk magnitude and the likelihood of acting to decrease risk. However, the mechanisms through which these effects work are poorly understood. To explore these mechanisms using a real-world scenario, we examined the relative impact of two graphical displays for depicting the risk of exposure to unexploded ammunition during potential land redevelopment. One display depicted only the foreground information graphically (a bar graph of the number of people harmed), and a second depicted the foreground and background graphically (a stacked bar graph representing both the number harmed and at risk). We presented 296 participants with either the foreground-only or the foreground and background graphical display and measured a broad set of outcome variables, examining (1) the graphical display effect on each of the outcome measures and (2) the pathways by which any display effects work to influence decision making. We found that the foreground-only graphical display increased perceived likelihood and experienced fear, which produced greater worry, which in turn increased risk aversion. In addition, a positive evaluation of the communication materials increased support for policies related to land redevelopment, whether those policies were risk taking or risk mitigating. Finally, the foreground-only graphical display decreased understanding of the risk magnitude, showing that approaches to accomplish one risk communication goal (promoting risk-averse decisions) may do so at the expense of another goal (increasing understanding).

Exposure to Contaminated Drinking Water and Health Disparities in North Carolina.

OBJECTIVES: To examine drinking water quality in majority Black periurban neighborhoods in Wake County, North Carolina, that are excluded from nearby municipal water service and to estimate the health benefits of extending water service. METHODS: We tested 3 samples collected July through December 2014 in 57 private wells for microbial contaminants. We compared contaminant prevalences to those in adjacent community water systems (35 280 samples from routine monitoring). Using a population intervention model, we assessed the number of annual emergency department visits for acute gastrointestinal illness that is preventable by extending water services to the 3799 residents of these periurban communities. RESULTS: Overall, 29.2% of 171 private well samples tested positive for total coliform bacteria and 6.43% for Escherichia coli, compared with 0.556% and 0.00850% of municipal system samples. An estimated 22% of 114 annual emergency department visits for acute gastrointestinal illness could be prevented by extending community water service. CONCLUSIONS: Predominantly Black periurban neighborhoods excluded from municipal water service have poorer quality drinking water than do adjacent neighborhoods with municipal services. These disparities increase the risk of emergency department visits for acute gastrointestinal illness.

Indoor Air Contamination from Hazardous Waste Sites: Improving the Evidence Base for Decision-Making.

At hazardous waste sites, volatile chemicals can migrate through groundwater and soil into buildings, a process known as vapor intrusion. Due to increasing recognition of vapor intrusion as a potential indoor air pollution source, in 2015 the U.S. Environmental Protection Agency (EPA) released a new vapor intrusion guidance document. The guidance specifies two conditions for demonstrating that remediation is needed: (1) proof of a vapor intrusion pathway; and (2) evidence that human health risks exceed established thresholds (for example, one excess cancer among 10,000 exposed people). However, the guidance lacks details on methods for demonstrating these conditions. We review current evidence suggesting that monitoring and modeling approaches commonly employed at vapor intrusion sites do not adequately characterize long-term exposure and in many cases may underestimate risks. On the basis of this evidence, we recommend specific approaches to monitoring and modeling to account for these uncertainties. We propose a value of information approach to integrate the lines of evidence at a site and determine if more information is needed before deciding whether the two conditions specified in the vapor intrusion guidance are satisfied. To facilitate data collection and decision-making, we recommend a multi-directional community engagement strategy and consideration of environment justice concerns.

Health Impacts of Increased Physical Activity from Changes in Transportation Infrastructure: Quantitative Estimates for Three Communities.

Recently, two quantitative tools have emerged for predicting the health impacts of projects that change population physical activity: the Health Economic Assessment Tool (HEAT) and Dynamic Modeling for Health Impact Assessment (DYNAMO-HIA). HEAT has been used to support health impact assessments of transportation infrastructure projects, but DYNAMO-HIA has not been previously employed for this purpose nor have the two tools been compared. To demonstrate the use of DYNAMO-HIA for supporting health impact assessments of transportation infrastructure projects, we employed the model in three communities (urban, suburban, and rural) in North Carolina. We also compared DYNAMO-HIA and HEAT predictions in the urban community. Using DYNAMO-HIA, we estimated benefit-cost ratios of 20.2 (95% C.I.: 8.7-30.6), 0.6 (0.3-0.9), and 4.7 (2.1-7.1) for the urban, suburban, and rural projects, respectively. For a 40-year time period, the HEAT predictions of deaths avoided by the urban infrastructure project were three times as high as DYNAMO-HIA's predictions due to HEAT's inability to account for changing population health characteristics over time. Quantitative health impact assessment coupled with economic valuation is a powerful tool for integrating health considerations into transportation decision-making. However, to avoid overestimating benefits, such quantitative HIAs should use dynamic, rather than static, approaches.

Predicting urban design effects on physical activity and public health: A case study.

With increasing global concerns about obesity and related health effects, tools to predict how urban form affects population physical activity and health are needed. However, such tools have not been well established. This article develops a computer simulation model for forecasting the health effects of urban features that promote walking. The article demonstrates the model using a proposed small-area plan for a neighborhood of 10,400 residents in Raleigh, North Carolina, one of the fastest-growing and most sprawling U.S. cities. The simulation model predicts that the plan would increase average daily time spent walking for transportation by 17 min. As a result, annual deaths from all causes are predicted to decrease by 5.5%. Annual new cases of diabetes, coronary heart disease, stroke, and hypertension are predicted to decline by 1.9%, 2.3%, 1.3%, and 1.6%, respectively. The present value of these health benefits is $21,000 per resident.

Deaths and medical visits attributable to environmental pollution in the United Arab Emirates.

BACKGROUND: This study estimates the potential health gains achievable in the United Arab Emirates (UAE) with improved controls on environmental pollution. The UAE is an emerging economy in which population health risks have shifted rapidly from infectious diseases to chronic conditions observed in developed nations. The UAE government commissioned this work as part of an environmental health strategic planning project intended to address this shift in the nature of the country's disease burden. METHODS AND FINDINGS: We assessed the burden of disease attributable to six environmental exposure routes outdoor air, indoor air, drinking water, coastal water, occupational environments, and climate change. For every exposure route, we integrated UAE environmental monitoring and public health data in a spatially resolved Monte Carlo simulation model to estimate the annual disease burden attributable to selected pollutants. The assessment included the entire UAE population (4.5 million for the year of analysis). The study found that outdoor air pollution was the leading contributor to mortality, with 651 attributable deaths (95% confidence interval [CI] 143-1,440), or 7.3% of all deaths. Indoor air pollution and occupational exposures were the second and third leading contributors to mortality, with 153 (95% CI 85-216) and 46 attributable deaths (95% CI 26-72), respectively. The leading contributor to health-care facility visits was drinking water pollution, to which 46,600 (95% CI 15,300-61,400) health-care facility visits were attributed (about 15% of the visits for all the diseases considered in this study). Major study limitations included (1) a lack of information needed to translate health-care facility visits to quality-adjusted-life-year estimates and (2) insufficient spatial coverage of environmental data. CONCLUSIONS: Based on international comparisons, the UAE's environmental disease burden is low for all factors except outdoor air pollution. From a public health perspective, reducing pollutant emissions to outdoor air should be a high priority for the UAE's environmental agencies.

Communicating quantitative information about unexploded ordnance risks to the public.

Military base closures have left 600,000 acres of U.S. land contaminated with unexploded ordnance (UXO). Recent research has demonstrated a method for quantifying the probability of residual UXO harming future land users. Here, we explore how a community neighboring a closed, UXO-contaminated military base responds to the probabilistic risk information this method produces. We explore how probabilistic information affects their risk understanding, risk management preferences, risk perceptions, and worry. We test eight different communication formats employing varying combinations of textual risk descriptions, comparative risk information, stacked bar graphs illustrating the proportion of future land users at risk, and textual summaries and/or graphical histograms presenting uncertainty. We find that stacked bar graphs double the odds of correctly reporting the probability of harm and decrease the perceived risk, compared to textual descriptions. Providing histograms or summary uncertainty information decreases the odds of correctly reporting the probability of harm by about one-half, compared to communications without uncertainty information. We also find that risk communication formats do not alter risk management preferences. We recommend that as EPA reevaluates its UXO risk management policies in the coming year, the agency shift to quantitative rather than its current qualitative approach to assessing and communicating UXO risks.