Private Drinking Water Supplies Research Articles

Incidence of per- and polyfluoroalkyl substances (PFAS) in private drinking water supplies in Southwest Virginia, USA

Per- and polyfluoroalkyl substances (PFAS) are a class of man-made contaminants of human health concern due to their resistance to degradation, widespread environmental occurrence, bioaccumulation in living organisms, and potential negative health impacts. Private drinking water supplies may be uniquely vulnerable to PFAS contamination in impacted areas, as these systems are not protected under federal regulations and often include limited treatment or remediation, if contaminated, prior to use. The goal of this study was to determine the incidence of PFAS contamination in private drinking water supplies in two counties in Southwest Virginia, USA (Floyd and Roanoke) that share similar bedrock geologies, are representative of different state Department of Health risk categories, and to examine the potential for reliance on citizen-science based strategies for sample collection in subsequent efforts. Samples for inorganic ions, bacteria, and PFAS analysis were collected on separate occasions by participants and experts at the home drinking water point of use (POU) for comparison. Experts also collected outside tap samples for analysis of 30 PFAS compounds. At least one PFAS was detectable in 95 % of POU samples collected (n = 60), with a mean total PFAS concentration of 23.5 ± 30.8 ppt. PFOA and PFOS, two PFAS compounds which presently have EPA health advisories, were detectable in 13 % and 22 % of POU samples, respectively. On average, each POU sample contained >3 PFAS compounds, and one sample contained as many as 8 compounds, indicating that exposure to a mixture of PFAS in drinking water may be occurring. Although there were significant differences in total PFAS concentrations between expert and participant collected samples (Wilcoxon, alpha = 0.05), collector bias was inconsistent, and may be due to the time of day of sampling (i.e. morning, afternoon) or specific attributes of a given home. Further research is required to resolve sources of intra-sample variability.

Antimicrobial Resistance Is Prevalent in E. coli and Other Enterobacterales Isolated from Public and Private Drinking Water Supplies in the Republic of Ireland.

High levels of bacterial antimicrobial resistance (AMR) have been reported in many environmental studies conducted in Ireland and elsewhere. The inappropriate use of antibiotics in both human and animal healthcare as well as concentrations of residual antibiotics being released into the environment from wastewaters are thought to be contributing factors. Few reports of AMR in drinking water-associated microbes are available for Ireland or internationally. We analysed 201 enterobacterales from group water schemes and public and private water supplies, only the latter having been surveyed in Ireland previously. The organisms were identified using conventional or molecular techniques. Antimicrobial susceptibility testing for a range of antibiotics was performed using the ARIS 2X interpreted in accordance with EUCAST guidelines. A total of 53 Escherichia coli isolates, 37 Serratia species, 32 Enterobacter species and enterobacterales from seven other genera were identified. A total of 55% of isolates were amoxicillin resistant, and 22% were amoxicillin-clavulanic acid resistant. A lower level of resistance (<10%) was observed to aztreonam, chloramphenicol, ciprofloxacin, gentamicin, ceftriaxone and trimethoprim-sulfamethoxazole. No resistance to amikacin, piperacillin/tazobactam, ertapenem or meropenem was detected. The level of AMR detected in this study was low but not insignificant and justifies ongoing surveillance of drinking water as a potential source of antimicrobial resistance.

A fatal case of Shiga toxin-producing Escherichia coli linked to a private drinking water supply.

In May 2017, a fatal case of Shiga toxin-producing &lt;i&gt;Escherichia coli&lt;/i&gt; (STEC) with haemolytic uremic syndrome was investigated by the Victorian Department of Health and Human Services and a local government authority. Investigation revealed the case used rainwater harvested from the roof of their home and stored in tanks as a private drinking water supply, despite the availability of a reticulated supply from the local water authority. &lt;i&gt;Escherichia coli&lt;/I&gt; Stx1 and Stx2 genes were detected in a water sample collected from the private drinking water supply, consistent with those earlier identified in the case’s faecal sample. This case study highlights the potential risks of STEC infection from private drinking water supplies, the importance of proper maintenance of such supplies, and the preferable use of reticulated water supplies when available. It also demonstrated an effective collaboration between local and state government for an environmental public health investigation.

El abastecimiento de agua a Barcelona (1850-1936): Origen y desarrollo de las compañías privadas

En este trabajo se analiza el papel que jugaron las empresas privadas de abastecimiento de agua potable en la modernización de la ciudad de Barcelona durante las últimas décadas del XIX y las primeras del siglo XX. La necesidad de extender una novedosa y completa red de abastecimiento de agua, obligó a la búsqueda de soluciones legales, técnicas y urbanísticas. Prosperidad industrial y crecimiento de la población se dieron la mano en la creación de una ciudad cada vez más populosa y moderna. Este conjunto de acciones desembocó en el diseño de redes que configuraron la traza de la nueva ciudad, al mismo tiempo que propiciaron la aparición de empresas que pugnaron -entre ellas y con el Ayuntamiento-, por el dominio y el control del mercado.

Spatial clustering of metal and metalloid mixtures in unregulated water sources on the Navajo Nation – Arizona, New Mexico, and Utah, USA

Contaminant mixtures are identified regularly in public and private drinking water supplies throughout the United States; however, the complex and often correlated nature of mixtures makes identification of relevant combinations challenging. This study employed a Bayesian clustering method to identify subgroups of water sources with similar metal and metalloid profiles. Additionally, a spatial scan statistic assessed spatial clustering of these subgroups and a human health metric was applied to investigate potential for human toxicity. These methods were applied to a dataset comprised of metal and metalloid measurements from unregulated water sources located on the Navajo Nation, in the southwest United States. Results indicated distinct subgroups of water sources with similar contaminant profiles and that some of these subgroups were spatially clustered. Several profiles had metal and metalloid concentrations that may have potential for human toxicity including arsenic, uranium, lead, manganese, and selenium. This approach may be useful for identifying mixtures in water sources, spatially evaluating the clusters, and help inform toxicological research investigating mixtures.

Estimating the population exposed to arsenic from groundwater-sourced private drinking water supplies in Cornwall, UK

Introduction: Many properties in the UK are served by private water supplies (PWS) where mains connection is not possible. Chronic exposure to chemicals in PWS may have an adverse effect on health causing cancers and skin lesions, although no evidence observed in the UK. The SW of England is an area with elevated arsenic concentrations in groundwaters supplying a number of domestic property PWS. A Prescribed Concentration Value (PCV) of 10 µg/L is set by Regulations enforced by local authorities. However, there remains uncertainty as to the precise extent of the local population exposed to arsenic. We undertook to calculate exposure to arsenic in PWS in Cornwall to help estimate the health burden. Methods: We invited known PWS users on a register to take part in a water sampling programme from 2011-13. We asked for information on the number of residents drinking PWS water and if properties shared the supply. The number of PWS in Cornwall and mean household population was estimated using GIS. We calculated population exposure to the range of concentrations found in samples. Results: 497 PWS were sampled, serving 868 properties supplying 1,979 (95% CI 1,901-2,057) residents. An estimated 4,044 properties are served by PWS in Cornwall supplying 9,625 (95% CI 9,504-9,746) people. The proportion of the population exposed to arsenic levels ranged from 71%: &lt;1µg/L, 24%: 1-10µg/L and 5%: &gt;10µg/L. Conclusions: Extrapolation estimates that 600 people are drinking water over the PCV in Cornwall. Households were given public health advice and recommendations to regularly test water for arsenic.

Urinary arsenic profiles reveal exposures to inorganic arsenic from private drinking water supplies in Cornwall, UK.

Private water supplies (PWS) in Cornwall, South West England exceeded the current WHO guidance value and UK prescribed concentration or value (PCV) for arsenic of 10 μg/L in 5% of properties surveyed (n = 497). In this follow-up study, the first of its kind in the UK, volunteers (n = 207) from 127 households who used their PWS for drinking, provided urine and drinking water samples for total As determination by inductively coupled plasma mass spectrometry (ICP-MS) and urinary As speciation by high performance liquid chromatography ICP-MS (HPLC-ICP-MS). Arsenic concentrations exceeding 10 μg/L were found in the PWS of 10% of the volunteers. Unadjusted total urinary As concentrations were poorly correlated (Spearman’s ρ = 0.36 (P < 0.001)) with PWS As largely due to the use of spot urine samples and the dominance of arsenobetaine (AB) from seafood sources. However, the osmolality adjusted sum, U-AsIMM, of urinary inorganic As species, arsenite (AsIII) and arsenate (AsV), and their metabolites, methylarsonate (MA) and dimethylarsinate (DMA), was found to strongly correlate (Spearman’s ρ: 0.62 (P < 0.001)) with PWS As, indicating private water supplies as the dominant source of inorganic As exposure in the study population of PWS users.

Meeting the public health challenge of protecting private wells: Proceedings and recommendations from an expert panel workshop

Private wells serving fewer than 25 people are federally unregulated, and their users may be exposed to naturally occurring agents of concern such as arsenic and radionuclides, as well as anthropogenic contaminants. The Centers for Disease Control and Prevention's Clean Water for Health Program works to protect private wells and prevent adverse health outcomes for the roughly 15% of Americans who rely on them. To understand current and emerging challenges to the private drinking water supply, an interdisciplinary expert panel workshop on “Future and Emerging Issues for Private Wells” was organized to inform strategic planning for the Clean Water for Health Program. The panel assessed current conditions of ground water as a source for private wells, identified emerging threats, critical gaps in knowledge, and public health needs, and recommended strategies to guide future activities to ensure the safety of private drinking water wells. These strategies addressed topics of broad interest to the environmental public health community including: development of new methods to support citizen science; addressing contaminant mixtures; expanding capacity for well testing; evaluating treatment technologies; building an evidence base on best practices on well owner outreach and stewardship; and research and data needs.

Variability in the chemistry of private drinking water supplies and the impact of domestic treatment systems on water quality.

Tap water from 497 properties using private water supplies, in an area of metalliferous and arsenic mineralisation (Cornwall, UK), was measured to assess the extent of compliance with chemical drinking water quality standards, and how this is influenced by householder water treatment decisions. The proportion of analyses exceeding water quality standards were high, with 65 % of tap water samples exceeding one or more chemical standards. The highest exceedances for health-based standards were nitrate (11 %) and arsenic (5 %). Arsenic had a maximum observed concentration of 440 µg/L. Exceedances were also high for pH (47 %), manganese (12 %) and aluminium (7 %), for which standards are set primarily on aesthetic grounds. However, the highest observed concentrations of manganese and aluminium also exceeded relevant health-based guidelines. Significant reductions in concentrations of aluminium, cadmium, copper, lead and/or nickel were found in tap waters where households were successfully treating low-pH groundwaters, and similar adventitious results were found for arsenic and nickel where treatment was installed for iron and/or manganese removal, and successful treatment specifically to decrease tap water arsenic concentrations was observed at two properties where it was installed. However, 31 % of samples where pH treatment was reported had pH < 6.5 (the minimum value in the drinking water regulations), suggesting widespread problems with system maintenance. Other examples of ineffectual treatment are seen in failed responses post-treatment, including for nitrate. This demonstrates that even where the tap waters are considered to be treated, they may still fail one or more drinking water quality standards. We find that the degree of drinking water standard exceedances warrant further work to understand environmental controls and the location of high concentrations. We also found that residents were more willing to accept drinking water with high metal (iron and manganese) concentrations than international guidelines assume. These findings point to the need for regulators to reinforce the guidance on drinking water quality standards to private water supply users, and the benefits to long-term health of complying with these, even in areas where treated mains water is widely available.Electronic supplementary materialThe online version of this article (doi:10.1007/s10653-016-9798-0) contains supplementary material, which is available to authorized users.

Urinary Arsenic Biomonitoring Results In Relation To Inorganic Arsenic In Private Drinking Water Supplies In Cornwall, South West England

Cornwall, UK is a region with high concentrations of environmental arsenic (As). Previous studies found elevated concentrations in urine and toenails of some local residents. Private water supply (PWS) usage is relatively common in Cornwall with an estimated 60,000 people served. A recent British Geological survey and Public Health England survey of 512 households across Cornwall found 5.5 % of drinking water samples with As exceeding 10 µg/L, the UK Prescribed Concentration Value.. We report here a subsequent urinary biomonitoring survey in a sample of these households to (1) quantify human exposure to inorganic As, and (2) assess the importance of PWS as an exposure route. Volunteers (n=207) in 127 households provided a first morning void or spot urine sample for As speciation (by HPLC-ICP-MS), along with hair and toenail samples to reflect longer term exposure (Middleton et al, submitted and presented at the 6th International Conference on Medical Geology, Aveiro, Portugal, July 2015). Environmental sampling was conducted to assess the relevance of various exposure routes. A tap water sample from the private supply was taken for total As determination (by ICP-MS), to capture the exposure level relevant via this pathway at the time of bio monitoring. Where possible, a garden topsoil sample, an indoor dust wipe sample and a small amount of rice (a foodstuff known to contribute to population arsenic intake) were collected from each household. Eight urine samples (4%) exceeded the guidance value of 35 μg/l of inorganic arsenic plus methylated metabolites set by the American Conference of Governmental Industrial Hygienists (ACGIH). The significant correlation between water and urine concentrations reflects drinking water as the main route of exposure. Individual results have been fed back to participants along with tailored advice on exposure reduction. Ongoing work is assessing the relative contributions of food, contaminated soil and household dust.

Arsenic in private drinking water wells: an assessment of jurisdictional regulations and guidelines for risk remediation in North America.

Arsenic is a known carcinogen found globally in groundwater supplies due to natural geological occurrence. Levels exceeding the internationally recognized safe drinking water standard of 10 μg/L have been found in private drinking water supplies in many parts of Canada and the United States. Emerging epidemiological evidence confirms groundwater arsenic to be a significant health concern, even at the low to moderate levels typically found in this region. These findings, coupled with survey data reporting limited public adherence to testing and treatment guidelines, have prompted calls for improved protective measures for private well users. The purpose of this review is to assess current jurisdictional provisions for private well water protection in areas where arsenic is known to naturally occur in groundwater at elevated levels. Significant limitations in risk management approaches are identified, including inconsistent and uncoordinated risk communication approaches, lack of support mechanisms for routine water testing and limited government resources to check that testing and treatment guidelines are followed. Key action areas are discussed that can help to build regulatory, community and individual capacity for improved protection of private well water supplies and enhancement of public health.

Nitrate-nitrogen levels in rural drinking water: Is there an association with age-related macular degeneration?

We examined the association of nitrate-nitrogen exposure from rural private drinking water and incidence of age-related macular degeneration (AMD). All participants in the Beaver Dam Eye Study (53916 improvement plan code) completed a questionnaire and had an ocular examination including standardized, graded fundus photographs at five examinations. Only information from rural residents in that study are included in this report. Data from an environmental monitoring study with probabilistic-based agro-chemical sampling, including nitrate-nitrogen, of rural private drinking water were available. Incidence of early AMD was associated with elevated nitrate-nitrogen levels in rural private drinking water supply (10.0% for low, 19.2% for medium, and 26.1% for high nitrate-nitrogen level in the right eye). The odds ratios (ORs) were 1.77 (95% confidence interval [CI]: 1.12–2.78) for medium and 2.88 (95% CI: 1.59–5.23) for high nitrate-nitrogen level. Incidence of late AMD was increased for those with medium or high levels of nitrate-nitrogen compared to low levels (2.3% for low and 5.1% for the medium or high nitrate-nitrogen level, for the right eye). The OR for medium or high nitrate-nitrogen groups was 2.80 (95% CI: 1.07–7.31) compared to the low nitrate-nitrogen group.

Arsenic in private drinking water supplies: human health risk based on underlying geology

Background Revised regulations governing the quality of private drinking water supplies (PWS) were introduced in 2008 as EU Directives, and transposed into UK Regulations in 2009, but there is a lack of coordinated information on the geographical distribution of known hazards such as those related to arsenic (As) and underlying geology. Aim To explore a methodology for risk assessment of exposure to As in drinking water based on the underlying geology and exceedances of the permissible limit. Methods Households in Cornwall with a PWS were identified from a register and a subset was selected to represent areas of different underlying geology. Approximately 500 residents were invited to provide tap and borehole water samples and information on water use. Water samples were analysed for As and other chemical parameters by ICP-MS and ion chromatography. The geological classification of the bedrock was complex in the study area with a need to simplify the categorisation in order characterise exposure in relation to geology. The British Geological Survey simplified this to 8 categories for practical analysis. Results In the first phase of the study covering east Cornwall in 2011, 258 PWS were sampled. Out of the 8 simplified geologies, Mineralisation areas and Gramscatho were more likely to have higher levels of As than others. A possible risk variation by geology category was found, but statistical significance was only borderline. Households found to have water supplies with exceedances for As or other hazards were advised about re-testing and interventions such as water treatment. Conclusions Potential exposure of a proportion of the Cornwall population to As was identified. In relation to risk related to underlying geology, there is an indication that some geologies are more likely to have higher levels of arsenic than others. Results of further analyses in a wider sampling area will estimate the potential influence of geology on the exposure of the population.

Arsenic in private drinking water supplies: population exposure assessment validated by biomonitoring.

Arsenic in private drinking water supplies: population exposure assessment validated by biomonitoring.

Quantitative analysis of microbial contamination in private drinking water supply systems

Over one million households rely on private water supplies (e.g. well, spring, cistern) in the Commonwealth of Virginia, USA. The present study tested 538 private wells and springs in 20 Virginia counties for total coliforms (TCs) and Escherichia coli along with a suite of chemical contaminants. A logistic regression analysis was used to investigate potential correlations between TC contamination and chemical parameters (e.g. NO3(-), turbidity), as well as homeowner-provided survey data describing system characteristics and perceived water quality. Of the 538 samples collected, 41% (n = 221) were positive for TCs and 10% (n = 53) for E. coli. Chemical parameters were not statistically predictive of microbial contamination. Well depth, water treatment, and farm location proximate to the water supply were factors in a regression model that predicted presence/absence of TCs with 74% accuracy. Microbial and chemical source tracking techniques (Bacteroides gene Bac32F and HF183 detection via polymerase chain reaction and optical brightener detection via fluorometry) identified four samples as likely contaminated with human wastewater.

Speciation of Organic Matter and Heavy Metals in Urban Wastewaters from an Emerging Country

Analytical scanning and transmission electron microscopy, sequential chemical extraction, and pyrolysis–gas chromatography on solvent-extractable organic matter are used to provide both direct and indirect speciation of heavy metals and organic matter in sewage-suspended solids and in biofilms taken from an urban sewer in an emerging country. Compared to developed countries where the domestic activities represent the main source of heavy metal pollution in wastewater, the combined sewer system of an emerging country also integrates significant contributions originating from the private drinking water supply system (Zn, Cu, Cr, and Ni), industrial discharges (Cu, Mn), and road dust transported by street washing (Pb). The relative importance of those sources changes drastically over time as evidenced by the difference in metal levels recorded between weekday and weekend effluents. Nevertheless, sewer biofilms are found to provide a good averaging of contaminant loads and they can be used as environmental archives. The speciation study reveals the predominance of neoformed minerals such as sulfides and phosphates and highlights the strong biogeochemical dynamics that takes place within the sewer system. Electron microscope observations of heavy metal-bearing phases proved to be necessary to provide a consistent interpretation of chemical extraction results. The molecular characterization of the solvent-extractable organic matter from biofilms reveals the presence of classical fingerprints of domestic activity such as fecal sterols and detergents but also confirms a major contribution of petroleum by-products consistent with a traffic-related pollution.

Microbiological assessment of private drinking water supplies in Co. Cork, Ireland

The microbiological quality of 75 private drinking water supply boreholes in Co. Cork, Ireland was assessed in order to determine the incidence of contamination and the potential pathways of such contamination. Microbiological analysis was carried out using the membrane filtration technique for the recovery of thermotolerant (faecal) coliforms. The sanitary protection of the supplies was evaluated by means of systematic inspections and subsequent qualitative sanitary risk assessment. Almost a quarter of all supplies investigated (24%, n = 18) was found positive for thermotolerant coliforms. Weather conditions had a significant impact on microbiological water quality, increasing both contamination incidence and gross contamination frequency. Over half of the supplies had nine or more sanitary hazards and most had rudimentary sanitary protection measures at the head of the borehole. These low sanitary protection measures suggest that boreholes can pose a significant hazard to valuable groundwater resources by providing direct contamination routes.

Private drinking water supplies: challenges for public health

Compared with people in many developing areas throughout the world, Canadians are fortunate to have access to safe drinking water and adequate sanitation. Globally, most diarrheal diseases — responsible for nearly two million deaths a year — can be attributed to unsafe water supplies as well as

Microbiological surveillance of private water supplies in England – The impact of environmental and climate factors on water quality

A passive surveillance system captured information on 34,904 microbiological samples from 11,233 private drinking water supplies within England as well as the associated constructional, climatic and environmental variables. Escherichia coli was detected in 6588 (18.87%) of samples and at least one positive sample was detected from 3638 (32.39%) of sites. However, this estimate of supplies failing to meet the European drinking water E. coli standard was probably an underestimate as the more samples taken per supply, the more likely the supply was to fail. A multivariable model of private water supplies data showed a strong seasonal impact, with samples between January and May being significantly less contaminated with E. coli than samples between June and December. Samples from springs (OR 2.5, CI 2.0–3.1) or surface waters (OR 2.4, CI 0.8–7.0) were more likely to fail than groundwater sources, as were supplies with no effective treatment (OR1.8, CI 1.5–2.3). Commercial supplies were less likely to fail than domestic supplies (OR 0.63, CI 0.48–0.83) and the probability of failure was linearly associated with the density of sheep in the area and rainfall on the previous day. A Monte Carlo modelling approach was used to estimate that, had sufficient samples been taken, 54% (95% confidence intervals 49–59%) of all private water supplies in England were likely to be unsatisfactory. These findings will be able to inform risk assessments of private water supplies prior to microbiological results being available.

Microbial pollution of water by livestock: approaches to risk assessment and mitigation

In this study, we investigate the extent to which the incidence of Escherichia coli O157:H7 can be predicted in human faeces, from human intake and infection via water contaminated by livestock and carrying this zoonotic pathogen in North-East (NE) and South-West (SW) regions of Scotland. In SW Scotland, there is a risk of coastal recreational waters failing EU standards for faecal indicator organisms, and this is assumed to be the main potential waterborne route of infection. In NE Scotland, the main waterborne route is assumed to be the many private drinking water supplies; these are mainly derived from shallow groundwater and surveys show that there is potential for significant levels of microbial contamination from livestock. The risk to human health from these sources has been assessed using a combination of process models, epidemiological risk-assessment methods and survey data. A key assumption in the calculations is the amount of mixing of pathogenic and non-pathogenic E. coli between animal faecal sources and contaminated water intake by humans. Using the probability distributions of the E. coli O157 content of individual faecal pat material (which would imply no mixing between source and human intake), based on three recent surveys of animal faeces in Scotland, led to predicted annual risks of infection slightly higher than observed human infection incidence. Using the geometric mean to represent partial mixing (which theoretically may over- or underestimate incidence with a concave dose–response curve) gave infection rates similar to those observed for two of the three faecal surveys. Using the arithmetic mean led to over-prediction of risk. This is to be expected if the true dose–response curve is (such as the Beta-Poisson curve used here) concave. Other factors that may lead to over-prediction of incidence are discussed, including under-reporting, loss of infectivity as a result of environmental exposure, immunity and the appropriateness of the Beta-Poisson curve. It is concluded that better epidemiological data for calibration of the dose–response curve, better knowledge of the degree of mixing and understanding of immunity are key requirements for progress in process model-based predictions of infection rate. The paper also explores the potential of improved farm and catchment scale management to deliver cost-effective mitigation of pollution of bathing and drinking water by livestock zoonoses.