Municipal Water Source Research Articles

Association between Combined Sewer Overflow Events and Gastrointestinal Illness in Massachusetts Municipalities with and without River-Sourced Drinking Water, 2014-2019.

Combined sewer overflow (CSO) events release untreated wastewater into surface waterbodies during heavy precipitation and snowmelt. Combined sewer systems serve people in the United States, primarily in urban and suburban municipalities in the Midwest and Northeast. Predicted increases in heavy precipitation events driven by climate change underscore the importance of quantifying potential health risks associated with CSO events. The aims of this study were to a) estimate the association between CSO events (2014-2019) and emergency department (ED) visits for acute gastrointestinal illness (AGI) among Massachusetts municipalities that border a CSO-impacted river, and b) determine whether associations differ by municipal drinking water source. A case time-series design was used to estimate the association between daily cumulative upstream CSO discharge and ED visits for AGI over lag periods of 4, 7, and 14 days, adjusting for temporal trends, temperature, and precipitation. Associations between CSO events and AGI were also compared by municipal drinking water source (CSO-impacted river vs. other sources). Extreme upstream CSO discharge events (th percentile by cumulative volume) were associated with a cumulative risk ratio (CRR) of AGI of 1.22 [95% confidence interval (CI): 1.05, 1.42] over the next 4 days for all municipalities, and the association was robust after adjusting for precipitation [1.17 (95% CI: 0.98, 1.39)], although the CI includes the null. In municipalities with CSO-impacted drinking water sources, the adjusted association was somewhat less pronounced following 95th percentile CSO events [ 1.05 (95% CI: 0.82, 1.33)]. The adjusted CRR of AGI was 1.62 in all municipalities following 99th percentile CSO events (95% CI: 1.04, 2.51) and not statistically different when stratified by drinking water source. In municipalities bordering a CSO-impacted river in Massachusetts, extreme CSO events are associated with higher risk of AGI within 4 days. The largest CSO events are associated with increased risk of AGI regardless of drinking water source. https://doi.org/10.1289/EHP14213.

The Effects of the Flint water crisis on the educational outcomes of school-age children.

In 2014, the municipal water source in Flint, Michigan was switched, causing lead from aging pipes to leach into the city's drinking water. While lead exposure in Flint children increased modestly on average, some children were exposed to high lead levels. Surveys of Flint residents show the water crisis was also associated with increased levels of stress, anxiety, and depression. We use Michigan's administrative education data and utilize synthetic control methods to examine the impact of the crisis on Flint's school-age children. We find decreases in math achievement and increases in special needs classification, even among children living in homes with copper (rather than lead) water service lines. Low socioeconomic status students and younger students experienced the largest effects on math achievement, and boys experienced the largest effects on special needs classification. Our results point toward the broad negative effects of the crisis on children and suggest that existing estimates may substantially underestimate the overall societal cost of the crisis.

Cyanobacterial Contribution to Annual Cycles of Phytoplankton in Lake Murray, SC

Freshwater lakes provide valuable recreational and tourism resources and are a major source of municipal drinking water for local communities. A primary management goal for lake systems is the maintenance of good water quality and a healthy aquatic ecosystem. Blooms of harmful or noxious species of cyanobacteria can result in severe water quality degradation. The purpose of this project was to provide baseline data on phytoplankton community composition, with special emphasis on cyanobacteria, and water quality parameters for Lake Murray, SC. The objective of this study was to determine the annual cyanobacterial contribution to total phytoplankton biomass in the lower reaches of Lake Murray. Measurements for this study were obtained at weekly to biweekly intervals from May 2021 to August 2022 on the northeast side of Lake Murray Dam, SC. Phytoplankton community composition was determined using a combination of high-performance liquid chromatography (HPLC) and ChemTax methods to measure the relative abundances of different algal groups. The phytoplankton community in Lake Murray is composed of a diverse assemblage of primarily green algae, diatoms, cyanobacteria, cryptophytes, and dinoflagellates. Community structure varied seasonally and annually. Total phytoplankton biomass remained below 7 μg of chl a l-1 and never reached “bloom” proportions (e.g., > 40 μg of chl a l-1). Planktonic cyanobacteria were present year-round in the lower reaches of Lake Murray and comprised 5–40% of the total phytoplankton biomass. Peaks in cyanobacteria abundance occurred during the late summer months. Even at the peak in August 2021, concentrations of cyanobacteria were low (1.79 μg chl a l-1). Over annual cycles, cyanobacteria had a median chl a concentration of 0.63 μg l-1 and a median contribution of 14.9%. Although we were unable to identify any specific causal mechanisms for the fluctuations in cyanobacterial biomass, we demonstrated that cyanobacteria are a consistent component of the phytoplankton community in lower Lake Murray. Baseline measures of phytoplankton during “good” water quality conditions provide invaluable data essential for managers to establish criteria for early prediction of bloom events and evaluate the effectiveness of mitigation strategies. Departures from the norm, especially during the summer and early fall, may signal the beginning of a cyanobacterial (or other algal group) bloom and provide an early warning for recreational users and municipal water intakes.

When the first barrier fails: public health and policy implications of nitrate contamination of a municipal drinking water source in Aotearoa New Zealand

ABSTRACT Safe, good-quality drinking water is a foundation of public health. Its provision relies on multiple barriers, the first being the protection of source water. Source water refers to the bodies of water (aquifers, rivers, lakes, springs, reservoirs) from which communities and individuals take their drinking water. A large waterborne campylobacter outbreak in 2016 spurred the New Zealand government to make a suite of legislative and policy reforms to strengthen the country’s drinking water supply system. However, the nitrate contamination of a municipal drinking water source, and its subsequent breach of drinking water standards, should bring renewed attention to the protection of source water. This article presents a case study of the exceedance and a review of legislation and policy governing drinking water sources. It finds that while important steps have been made since 2016, weaknesses in responsibility and accountability remain in Aotearoa’s drinking water supply system.

Factors associated with per- and polyfluoroalkyl substances (PFAS) serum concentrations in residents of New Hanover County, North Carolina: The GenX exposure study

In 2017, people living in New Hanover County, North Carolina, learned that for ∼40 years they were unknowingly exposed to per- and polyfluoroalkyl substances (PFAS) through drinking water sourced by the Cape Fear River. Using data from the GenX Exposure Study, which measured serum PFAS levels in county residents, we aimed to understand questionnaire-measured factors associated with serum PFAS levels. Because most residents were served by the same municipal water source, we focused on surrogate factors of drinking water exposure that may contribute to variability in PFAS levels. Our analysis included 335 participants aged 6 and older. We included seven chemicals detected in ≥75% of the study population: four well-studied perfluoroalkyl acids (PFOA, PFOS, PFNA, PFHxS) and three understudied fluoroethers (Nafion byproduct 2, PFO4DA, PFO5DoA). For each PFAS, we evaluated associations of variables with serum PFAS levels adjusting for key demographic characteristics. Additionally, we developed predictive models for each PFAS. We used years of residence in the lower Cape Fear Region as a surrogate for water consumption. Duration of drinking water exposure was associated with higher serum levels of all seven PFAS. Drinking municipal water treated by home filters or other sources of water (non-city) were associated with lower PFAS concentrations for all seven PFAS compared to drinking municipal water without additional filtration. Males had higher levels of well-studied PFAS, but there was no difference for fluoroethers. For six PFAS, the predictive models explained ≥30% of the variance in serum PFAS levels. While some factors were significantly associated with levels of individual PFAS, their relative importance to overall prediction was low, such as microwave popcorn consumption. Consistently, water consumption-related variables were important for both the association and predictive investigations. These analyses provide additional evidence that drinking water is a primary source for serum PFAS concentrations among New Hanover County residents.

Rainwater Harvesting as Sustainable Solution to Cope with Drinking Water Scarcity and Urban Flooding: A Case Study of Public Institutions in Lahore, Pakistan

Pakistan is currently facing physical and economic water scarcity issues, which have been further complicated by the rapid increase in its population and climate change. In affected areas, many methods are being used to tackle this problem, among which rainwater harvesting (RWH) provides the best alternative source of domestic water supply. In rainwater harvesting, a mechanism is designed to effectively collect surface runoff during rainfall events from residential rooftops. It has also been found that rainwater has great potential as a source of water supply in residential areas of major cities, such as Lahore, which is the focus of our study. This research paper examines rainwater harvesting as a sustainable solution to address the challenges of drinking water scarcity and urban flooding. The study discusses the benefits of rainwater harvesting, including reducing reliance on municipal water sources, improving water quality, and mitigating the impact of urban flooding. Additionally, the paper explores the use of filtered water points in conjunction with rainwater harvesting systems to provide clean drinking water to communities. The research draws on case studies from various regions to illustrate the effectiveness of rainwater harvesting as a sustainable solution to water scarcity and urban flooding. Ultimately, the study concludes that rainwater harvesting, when coupled with filtered water points, can offer an effective and sustainable solution to address drinking water scarcity and urban flooding.

Dechlorination of CDCl3 on Fe(111): Implications for disinfection by-product degradation

Disinfection by-products are produced in the water supply by reactions of organic matter with halogenated disinfectants. Remediation of disinfection by-products can be accomplished by decomposition through reductive dehalogenation or corrosion reactions. Iron is ubiquitous in soils and pipeline systems, which comes into contact with municipal water sources. This study investigated the decomposition of chloroform, a model disinfection by-product, with an Fe(111) surface to measure the dechlorination mechanism using surface vibrational spectroscopy at the gas/solid interface. It was found that chloroform physisorbs on Fe(111) at -118°C and undergoes dissociative adsorption above -50°C. Vibrational modes are compared with density functional theory cluster models to identify the molecular orientation and indicate a difference in the C-Cl stretching modes that is coverage dependent. The desorption energy of chloroform from Fe(111) was measured as 67.5 (+/- 0.018) kJ/mol for the monolayer and 52.7 (+/- 2.2) kJ/mol for the multilayer. At 25 °C, d-chloroform is shown to dissociate as observed by Auger electron spectroscopy. The co-adsorption of water vapor, provide OH sites on the iron surface that appears to block a fraction of surface sites, allowing for less adsorption and chlorine deposition on Fe(111). The results show that Fe0 sites catalyze the dechlorination of chloroform, while OH sites oxidize the surface, suggesting that in aqueous solutions, metallic Fe is needed for dehalogenation.

Variation of tap-water isotope ratios and municipal water sources across Kyiv city, Ukraine

Stable isotopes of water allow researchers to examine water pathways and better understand spatial and temporal variability in mixtures of municipal water sources. In regions such as Kyiv (Ukraine), with a water supply that is vulnerable to the effects of climate change, pollution, and geopolitical conflict, such understanding is critical for effective water management. Trends in stable isotope values and water sources can function as a confirmation of municipal data. Additionally, these data can provide an early signal for the effects of climate change on these sources, reducing uncertainty from physical measurements.For this study, tap water, surface water, and groundwater were collected over 14 months in Kyiv and nearby Boryspil, Brovary, and Boyarka and measured for hydrogen (δ2H) and oxygen (δ18O) stable isotopes. The stable isotope values from the tap water for each district show a general seasonal trend in water sources, with more groundwater used in the supply in the winter for most districts. Spatially, groundwater use increases from south to north in the left-bank districts in Kyiv city and groundwater use generally decreases from south to north in the right-bank districts. As precipitation patterns shift and temperatures increase, the reliance on particular water sources may need to shift as well. Overall, δ2H and δ18O data provide a baseline expectancy for current water use throughout the year and, from this, deviations can be assessed early.

AN ASSESSMENT OF PHYSICOCHEMICAL AND MICROBIOLOGICAL CHARACTERISTICS OF WATER IN INSUKAMINI CATCHMENT WATER SOURCES AND THE SUITABILITY OF WATER FOR DOMESTIC USE

Insukamini catchment depends on hand dug wells, sand water abstraction, dam, and borehole water sources for their domestic uses. On hand dug wells and sand water abstraction, people rely on natural filtration of bacteria and consider the water as safe, however the location and management of some of these water sources raise suspicion of possible contamination. The aim of this study was to assess drinking water quality in terms of selected physico-chemical and microbiological parameters, and people's perceptions on aesthetic parameters. Water samples were collected from five water sources, namely sand water abstraction, dam, hand dug well, borehole and municipal water. Three samples were collected from each water source to make 63 samples. Temperature, pH, electrical conductivity, and dissolved oxygen measured using HI 9143 dissolved oxygen meter, YSI pH 100, HI 9143 dissolved oxygen meter and HI 8633 conductivity meter respectively. On laboratory experiments total suspended solids measured using filter disk, total dissolved solids using gravimetric method (SA, 2008), total and feacal coliform were measured using spread plate method. All water sources had total coliform levels above the WHO standards for drinking water of 1000mg/L. For E. coli, borehole and municipal water sources complied with the WHO standard with the means of zero cfu/ 100ml. Low pH mean of 5.001 was found in borehole water and the other water sources were within the accepted range of 6.5 to 8.5. Municipal and dam point (A) water sources had highest levels of TDS, borehole, and dam point (C) had TSS levels above maximums allowable of 1000mg/L and 150mg/L respectively. Temperature, DO and EC of all water sources were within the WHO standards. Overall, all water sources were not complying with WHO standard for drinking water. People described municipal water source as best for drinking purpose, dam, sand water abstraction and hand dug well water sources described as soft and good for laundry and bathing as compared to borehole which was described as hard. The results indicated that water from the sources under study were not suitable for drinking purposes without treatment. The water should rather be used for other domestic uses such as laundry and bathing. However, municipal water should be boiled or use water purification tablets (chlorine tablets) before drinking. An integrated approach is therefore required to minimize and avoid water pollution within the catchment.

Hydrological behaviour of an unregulated eastern slope river under changing historical climate

The Elbow River is an eastern slope river with headwaters in the Rocky Mountains in Alberta whose major end-use is a critical source of municipal water for Calgary. Overwinter precipitation in its watershed falls primarily as snow and accumulates as snowpack until spring melt. Precipitation falls mainly as rain from May until October. The river is unregulated above Calgary’s water supply reservoir, and its relatively undeveloped watershed makes it ideal for examining potential climate change impacts on river hydrology. Available historical hydrometeorological data (1967 to 2015) from the basin were assessed to study its hydrological behaviour under a changing climate. The analysis showed significant upward trends in both flow and precipitation variables, especially from 1979 to 2015. Significant increases in both annual flow volume and annual maximum daily flow (AM-flow), and later seasonal occurrence of AM-flow, were not observed in other eastern slope rivers. Although these changes could attenuate predicted water supply shortages, they could also potentially increase flood magnitudes. The analysis also revealed that three sub-watersheds, which are approximately equal in geographic area, contributed differing flow volumes during the high-flow season (May to October). The upper watershed contributed most (∼68%), followed by the middle (∼26%) and lower (∼6%) watersheds, on average. Extreme high-flow events (ie >90th percentile AM-flow) were strongly related to high rainfall events, but not significantly related to snowpack loss (or melt). Moderate AM-flows were positively related to both the cumulative snowpack loss before the high-flow season and the cumulative antecedent precipitation prior to the AM-flow, suggesting that the antecedent soil moisture conditions could play a role. Predictions of climate change impacts on this eastern slope river’s hydrology should thus consider the effects of meteorological variables and the moisture conditions of the watershed.

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

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

Atypical and dual biotypes variant of virulent SA-NAG-Vibrio cholerae: an evidence of emerging/evolving patho-significant strain in municipal domestic water sources

Introduction and purposeThe recent cholera spread, new cases, and fatality continue to arouse concern in public health systems; however, interventions on control is at its peak yet statistics show continuous report. This study characterized atypical and patho-significant environmental Vibrio cholerae retrieved from ground/surface/domestic water in rural-urban-sub-urban locations of Amathole District municipality and Chris Hani District municipality, Eastern Cape Province, South Africa.MethodsDomestic/surface water was sampled and 759 presumptive V. cholerae isolates were retrieved using standard microbiological methods. Virulence phenotypic test: toxin co-regulated pili (tcp), choleragen red, protease production, lecithinase production, and lipase test were conducted. Serotyping using polyvalent antisera (Bengal and Ogawa/Inaba/Hikojima) and molecular typing: 16SrRNA, OmpW, serogroup (Vc-O1/O139), biotype (tcpAClas/El Tor, HlyAClas/El Tor, rstRClas/El Tor, RS1, rtxA, rtxC), and virulence (ctxA, ctxB, zot, ace, cep, prt, toxR, hlyA) genes were targeted.ResultResult of 16SrRNA typing confirmed 508 (66.9%) while OmpW detected/confirmed 61 (12.01%) V. cholerae strains. Phenotypic-biotyping scheme showed positive test to polymyxin B (68.9%), Voges proskauer (6.6%), and Bengal serology (11.5%). Whereas Vc-O1/O139 was negative, yet two of the isolates harbored the cholera toxin with a gene-type ctxB and hlyAClas: 2/61, revealing atypical/unusual/dual biotype phenotypic/genotypic features. Other potential atypical genotypes detected include rstR: 7/61, Cep: 15/61, ace: 20/61, hlyAElTor: 53/61, rtxA: 30/61, rtxC: 11/61, and prtV: 15/61 respectively.ConclusionAlthough additional patho-significant/virulent genotypes associated with epidemic/sporadic cholera cases were detected, an advanced, bioinformatics, and post-molecular evaluation is necessary. Such stride possesses potential to adequately minimize future cholera cases associated with dynamic/atypical environmental V. cholerae strains.

Ancient Waters from New Fountains: Municipal Water Sources in 15th-Century Haggadot from Nuremberg

Ancient Waters from New Fountains: Municipal Water Sources in 15th-Century Haggadot from Nuremberg

Living Filtration Membranes Demonstrate Antibiofouling Properties

Membrane filters are excellent prospects for increasing global access to safe water; however, they are significantly limited by fouling, particularly biofouling. Fouling plagues membranes by reducing efficiency and increasing maintenance and costs. Biofouling is particularly problematic due to the self-replicating nature of microorganisms and the secretion of extracellular polymeric substances that make the biofilm difficult to remove. Living filtration membranes (LFMs) are a sustainable membrane technology composed of bacterial cellulose and native microorganisms. In this study, natural water from Butte, Montana’s three municipal drinking water sources (Basin Creek Reservoir, Moulton Reservoir, and Big Hole River) was pretreated with a coagulant and used in 400 min bench-scale dead-end filtration tests. Two membranes were compared─an LFM and a commercial mixed cellulose ester (MCE) membrane with a similar nominal pore size. Although the MCE membrane was more hydrophilic and had a smoother surface, surface properties that, in general, may improve fouling resistance for certain particles, a more rapid flux decline and live biomass were observed with the MCE membrane for all three waters. We suggest that the LFM’s resistance to biofouling may be due to the proliferation of native bacteria, Acetobacter, which produces acetic acid, a known antibiofilm and antibacterial agent.

Tracking domestic wastewater and road de-icing salt in a municipal drinking water reservoir: Acesulfame and chloride as co-tracers

Developing strategies to identify the origins of contaminants in watersheds is crucial for source water protection. The use of multiple tracers improves the ability to identify contamination events originating from various land use activities. The objective of this study was to evaluate the use of acesulfame and chloride as co-tracers to represent the impact of pollution originating from wastewater and road de-icing on water quality in a municipal drinking water source. The study included a two-year sampling and water quality analysis program in numerous locations within a drinking water reservoir comprising a lake (upstream) and a river (downstream) which supply raw water to a municipal water treatment plant. Results showed that the spatial variability of acesulfame and chloride within the watershed of the lake-river systems depends on the location of contaminant sources, mainly municipal wastewater and septic tank discharges (for acesulfame) and the presence of small tributaries of the lake and river (for chloride). Temporal variability of the tracers under study differed according to the sampling location and was mainly affected by seasonal conditions. Correlation analyses between the two tracers in lake and river waters (in terms of concentrations and loads) made it possible to pinpoint the probable origins of contamination. The assessment of the spatio-temporal variability of these co-tracers within the lake-river watersheds allowed for the delineation of priority intervention zones as a decision-making tool for municipal authorities in improving drinking water source protection.

Utilization of Abandoned Coal Mines as Sources of Municipal Water

Utilization of Abandoned Coal Mines as Sources of Municipal Water

Ancient Waters from New Fountains: Municipal Water Sources in 15th-Century Haggadot from Nuremberg

Ancient Waters from New Fountains: Municipal Water Sources in 15th-Century Haggadot from Nuremberg

The Psychosocial Effects of the Flint Water Crisis on School-Age Children

Lead poisoning has well-known impacts for the developing brain of young children, with a large literature documenting the negative effects of elevated blood lead levels on academic and behavioral outcomes. In April of 2014, the municipal water source in Flint, Michigan was changed, causing lead from aging pipes to leach into the city’s drinking water. In this study, we use Michigan’s universe of longitudinal, student-level education records, combined with home water service line inspection data containing the location of lead pipes, to empirically examine the effect of the Flint Water Crisis on educational outcomes of Flint public school children. We leverage parallel causal identification strategies, a between-district synthetic control analysis and a within-Flint difference-in-differences analysis, to separate out the direct health effects of lead exposure from the broad effects of living in a community experiencing a crisis. Our results highlight a less well-appreciated consequence of the Flint Water Crisis – namely, the psychosocial effects of the crisis on the educational outcomes of school-age children. These findings suggest that cost estimates which rely only on the negative impact of direct lead exposure substantially underestimate the overall societal cost of the crisis.

DNA-based detection of Mycobacterium avium subsp. paratuberculosis in domestic and municipal water from Porto (Portugal), an area of high IBD prevalence.

Mycobacterium avium subsp. paratuberculosis (MAP) may play a role in the pathology of human inflammatory bowel disease (IBD). Previously, we found a high frequency (98% in patients with active disease) of MAP DNA detection in the blood of Portuguese Crohn's Disease patients, suggesting this cohort has high exposure to MAP organisms. Water is an important route for MAP dissemination, in this study we therefore aimed to assess MAP contamination within water sources in Porto area (the residential area of our IBD study cohort).Water and biofilms were collected in a wide variety of locations within the Porto area, including taps connected to domestic water sources and from municipal water distribution systems. Baseline samples were collected in early autumn plus further domestic water samples in early winter, to assess the effect of winter rainfall. DNA was extracted from all 131 samples and IS900-based nested PCR used to assess the frequency of MAP presence.Our results show high MAP positivity in municipal water sources (20.7% of water samples and 41.4% of biofilm samples) and even higher amongst domestic sources (30.8% of water samples and 50% of biofilm samples). MAP positivity in biofilms correlated with positivity in water samples from the same sources. A significantly higher frequency of MAP-positivity was observed during winter rains as compared with samples collected in autumn prior to the winter rainfall period (61.9% versus 30.8%). We conclude that domestic and municipal water sources of Porto region have a high burden of MAP contamination and this prevalence increases with rainfall. We hypothesize that human exposure to MAP from local water supplies is commonplace and represents a major route for MAP transmission and challenge which, if positively linked to disease pathology, may contribute to the observed high prevalence of IBD in Porto district.

Lead service lines and Parkinson’s disease prevalence in U.S. States

IntroductionWe recently showed that the prevalence of Parkinson’s Disease (PD) in U.S. states is positively associated with the quantity of acid rain. Acid rain could play an etiologic role in PD by mobilizing metals, e.g., lead, from watersheds and pipes into drinking water. We assessed the correlation of PD with lead service lines, the underground pipes that connect homes to municipal water sources, which are a major aqueous source of lead. MethodsWe used multiple regression techniques to examine PD prevalence rates by state relative to the number of lead service lines. We included known or suspected aqueous risk factors, e.g., the Acid Precipitation Index (a measure of acid rain) and well water use. ResultsAge-, race-, and sex-adjusted prevalence rates for PD were significantly and positively correlated with the log number of lead service lines (p = 0.0004). The effect of lead service lines remained significant after adjusting for the effects of acid rain and well water use (p = 0.0019). ConclusionThese findings are consistent with a role for lead in the etiology of PD. Studies of lead service line exposure in relation to PD at the individual level are warranted.