Private Wells Research Articles

Hydrogeochemical assessment of groundwater in transboundary aquifers along the US-Mexico border and drinking water quality implications for Texas Colonias

The groundwater resources in transboundary aquifers are crucial to the development of involved nations. A unified governance strategy based on scientific data is essential for the management of transboundary aquifers. This study presents a comprehensive geochemical analysis of the groundwater quality of private wells along the US-Mexico border in Texas across three transboundary aquifer types. The concentrations of dissolved major ions, trace, and rare earth elements (REE) were measured, and the dissolved organic matter was spectroscopically characterized to evaluate the prevailing water-rock interactions, biogeochemical reactions, and anthropogenic contamination in the groundwater and their susceptibility to future contamination. Groundwater samples were collected from private wells (n = 22) from four representative counties within a section of the Texas-Mexico border (Maverick, Kinney, Dimmit, and Webb Counties). Three distinct aquifer types were revealed from the major ion composition, e.g., a carbonate aquifer within Kinney County (a part of Edwards-Trinity aquifer), an alluvial aquifer with prevailing reducing conditions within Dimmit and Webb Counties (a part of Carrizo-Wilcox aquifer), and an evaporite-rich aquifer within Maverick County. The concentrations of trace elements in the groundwater of each aquifer type were below the MCL of USEPA, however, excessive Sr concentrations were evident mostly in the evaporite-rich aquifer. Our results indicate dissolution of evaporites, and possible anthropogenic contamination may be responsible for the degradation of groundwater quality in Maverick County, raising concern for the viability of the aquifer in the future.

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

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

Impact of COVID-19 health precautions on asymptomatic Streptococcus pyogenes carriage in palestinian children: a pre- and post-pandemic study

BackgroundStreptococcus pyogenes (Group A Streptococcus, GAS) is a significant pathogen that causes diverse infections, ranging from pharyngitis to severe invasive diseases. Asymptomatic carriage in children is pivotal for transmission. The COVID-19 pandemic’s health measures, including mask wearing and enhanced hand hygiene, likely influenced GAS transmission dynamics. This study evaluated the impact of these precautions on the prevalence of asymptomatic pharyngeal GAS carriage among schoolchildren in the southern West Bank, Palestine.MethodsThis cross-sectional study was conducted in two phases: pre-COVID-19 (November 2019–January 2020) and post-COVID-19 (November 2023–April 2024). Throat swabs were collected from 701 children (345 pre-COVID-19, 356 post-COVID-19) via cluster sampling. The samples were tested with the ABON Strep A rapid test and confirmed by culture. Sociodemographic, health, and household data were also collected. The statistical analyses included descriptive statistics, chi-square tests, and binary logistic regression.ResultsThe prevalence of asymptomatic pharyngeal GAS carriage declined from 15.7% pre-COVID-19 to 10.4% post-COVID-19 (p = 0.038). Significant reductions were observed among urban residents (23.5–10.1%, p = 0.003) and those from medium socioeconomic backgrounds (16.0–9.1%, p = 0.008). Compared with urban residents, rural residents had lower GAS carriage rates (adjusted OR = 0.505, p = 0.023). Carriage rates also decreased among children with frequent sore throats (17.6–7.3%, p = 0.007) and those using private wells (52.5–14.9%, p < 0.001). Higher BMI was a significant risk factor (adjusted OR = 17.68, p < 0.001), whereas frequent tooth brushing (adjusted OR = 0.055, p < 0.001) and hand washing (adjusted OR = 0.367, p < 0.001) were protective factors.ConclusionsCOVID-19-related health precautions were correlated with a significant reduction in asymptomatic GAS carriage among Palestinian children. These findings suggest that public health measures, such as mask wearing and hand hygiene, can influence the transmission of respiratory pathogens. Ongoing surveillance and targeted interventions are essential for managing GAS infections, particularly in resource-limited settings.

Perceived and Physical Quality of Drinking Water in Pavlodar and Akmola Rural Regions of Kazakhstan

Water quality in rural areas of developing countries is a notable problem. In this article, drinking water quality from eleven villages in the Pavlodar and the Akmola region of Kazakhstan was analyzed. Questionnaires of village respondents and chemical components of drinking water were analyzed to identify the quality of drinking water. In each of the villages, the chemical content varied depending on the source of drinking water. In the rural Pavlodar region, we observed that some cations and anions exceed the MPC. Respondents’ perceptions of water quality are associated with water sources and physical components. For example, respondents’ satisfaction by inside tap of central water systems’ water was high, the answers of those whose water source was private wells showed more mixed satisfaction levels. The drinking water physical quality indicators are closely related to water mineralization and general hardness. The total microbial count of drinking water has a significant relationship with respondents’ complaints about unpleasant taste, odor, and salinity. The relationship between perceived and physical water quality is a critical aspect of water resource management. By bridging the gap between scientific assessments and public perceptions, we can enhance public health, build trust in water management systems, and promote sustainability of water use.

Pricing drinking water testing in northern Haiti: Financial sensitivity to operating costs, user demand, and economic conditions

Safe drinking water availability is a concern in Haiti. Public systems have limited coverage and reliability. Private wells and local water sources are often of unknown or poor quality. Public health events, such as the 2010 cholera outbreak, demonstrate vulnerability to water contamination. To address these concerns, a drinking water laboratory was established at the Campus Henri Christophe in Limonade, a branch of the State University of Haiti, to meet water testing demands from local clients such as for-profit kiosks, institutions, industries, and municipal water systems. This study assessed the financial viability of a university-based drinking water laboratory in Haiti by calculating Internal Rate of Return and Net Present Value. Sensitivity analysis was used to identify the range of conditions under which laboratory revenues would cover operating costs. To achieve an acceptable profitability level, the laboratory must perform microbiological testing for routine monitoring samples and test an average of five samples per day. Price-based incentives for new clients have relatively small impacts on profitability. Finally, international and Haitian inflation cause some variation in profitability. These economic factors will be among the key drivers of laboratory operation costs. The results underscore the main factors that must be considered to make the laboratory successful and the importance of strategic marketing for laboratory managers to encourage clients to regularly test drinking water and emphasize microbiological testing.

A latent spatial class model for predicting a (semi-)metals mixture in private wells

A latent spatial class model for predicting a (semi-)metals mixture in private wells

Chronic low arsenic exposure in private wells and early markers of diabetes and cardiovascular health

Chronic low arsenic exposure in private wells and early markers of diabetes and cardiovascular health

Applying a hydroclimatological index to assess nitrate contamination in private drinking water wells across Iowa, USA from 1991-2011

Applying a hydroclimatological index to assess nitrate contamination in private drinking water wells across Iowa, USA from 1991-2011

Improving Private Well Testing Programs: Experimental Evidence from Iowa.

Approximately 23 million U.S. households rely on private wells for drinking water. This study first summarizes drinking water behaviors and perceptions from a large-scale survey of households that rely on private wells in Iowa. Few households test as frequently as recommended by public health experts. Around 40% of households do not regularly test, treat, or avoid their drinking water, suggesting pollution exposure may be widespread among this population. Next, we utilize a randomized control trial to study how nitrate test strips and information about a free, comprehensive water quality testing program influence households' behaviors and perceptions. The intervention significantly increased testing, including high-quality follow-up testing, but had limited statistically detectable impacts on other behaviors and perceptions. Households' willingness to pay for nitrate test kits and testing information exceeds program costs, suggesting that the intervention was welfare-enhancing.

A Mixed Methods Approach to Understanding the Public Health Impact of a School-Based Citizen Science Program to Reduce Arsenic in Private Well Water.

Exposure to arsenic (As) in well water is a well-documented public health issue for Maine and New Hampshire, as well as for other states in the United States and abroad. Arsenic contamination of well water in these locations is primarily attributed to metasedimentary bedrock that leaches As into groundwater. However, As can also enter groundwater reserves from soils contaminated by the historical use of arsenical pesticides. Approximately half of the households in Maine and New Hampshire rely on private wells, many of which have elevated As. Arsenic exposure has been associated with an increased risk of cancer, cardiovascular disease, reduced infection resistance, and lower intelligence quotient in children. Despite these known health impacts, well water testing and treatment are not universal. We have approached the problem of low well water testing rates in Maine and New Hampshire communities by developing the All About Arsenic (AAA) project, which engages secondary school teachers and students as citizen scientists in collecting well water samples for analysis of As and other toxic metals and supports their outreach efforts to their communities. We assessed this project's public health impact by analyzing student data relative to existing well water quality datasets in both states. In addition, we surveyed private well owners who contributed well water samples to the project to determine the actions taken to mitigate As in well water. Students collected 3,070 drinking water samples for metals testing, and 752 exceeded New Hampshire's As standard of . The AAA data has more than doubled the amount of information available to public health agencies about well water quality in multiple municipalities across both states. Students also collected information about well types and treatment systems. Their data reveal that some homeowners did not know what type of wells they had or whether they had filtration systems. Those with filtration systems were often unaware of the type of system, what the system was filtering for, or whether the system was designed to remove As. Through interviews with pilot survey participants, we learned that some had begun mitigating their exposure to As and other toxic metals in response to test results from the AAA project. A school-based approach to collecting and analyzing private well water samples can successfully reach communities with low testing rates for toxic elements, such as As and other metals. Importantly, information generated through the program can impact household decision-making, and students can influence local and state policymaking by sharing information in their communities. https://doi.org/10.1289/EHP13421.

A data-driven approach to identifying PFAS water sampling priorities in Colorado, United States.

Per and polyfluoroalkyl substances (PFAS), a class of environmentally and biologically persistent chemicals, have been used across many industries since the middle of the 20th century. Some PFAS have been linked to adverse health effects. Our objective was to incorporate known and potential PFAS sources, physical characteristics of the environment, and existing PFAS water sampling results into a PFAS risk prediction map that may be used to develop a PFAS water sampling prioritization plan for the Colorado Department of Public Health and Environment (CDPHE). We used random forest classification to develop a predictive surface of potential groundwater contamination from two PFAS, perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA). The model predicted PFAS risk at locations without sampling data into one of three risk categories after being "trained" with existing PFAS water sampling data. We used prediction results, variable importance ranking, and population characteristics to develop recommendations for sampling prioritization. Sensitivity and precision ranged from 58% to 90% in the final models, depending on the risk category. The model and prioritization approach identified private wells in specific census blocks, as well as schools, mobile home parks, and public water systems that rely on groundwater as priority sampling locations. We also identified data gaps including areas of the state with limited sampling and potential source types that need further investigation. This work uses random forest classification to predict the risk of groundwater contamination from two per- and polyfluoroalkyl substances (PFAS) across the state of Colorado, United States. We developed the prediction model using data on known and potential PFAS sources and physical characteristics of the environment, and "trained" the model using existing PFAS water sampling results. This data-driven approach identifies opportunities for PFAS water sampling prioritization as well as information gaps that, if filled, could improve model predictions. This work provides decision-makers information to effectively use limited resources towards protection of populations most susceptible to the impacts of PFAS exposure.

Adapting to PFAS contamination of private drinking water wells near a PFAS production facility in the US Atlantic Coastal Plain of North Carolina.

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are widespread groundwater contaminants and are present in over 7000 drinking water wells near a North Carolina (NC) PFAS plant (Chemours). To understand options available to affected residents, we used new and previously existing water quality data to investigate deeper aquifers as alternate drinking water supplies and compared the regulatory responses near Chemours and three other PFAS production facilities with nearby contaminated wells. Data from >100 wells show that GenX concentrations decrease with increasing depth through the four aquifers in the study area: surficial, Black Creek, Upper Cape Fear, and bedrock. This illustrates the extent of vertical PFAS penetration through the aquifer sequence following roughly 40 years of atmospheric emissions. Detailed data on 143 water quality parameters in nine deep wells (two Upper Cape Fear, seven bedrock) revealed only eight exceedances of drinking water standards (one each for arsenic, perfluorooctanoic acid [PFOA], iron, chloride, and gross alpha, and three for manganese) and nine exceedances of health advisories (all for sodium). Regulatory responses to PFAS contamination of wells in four states included mention of deeper wells as an alternate water source only for nonresidential users in NC and residential users in Vermont. The bedrock aquifer is currently used by some residents and may be a viable alternative to shallower groundwater, though arsenic treatment may be beneficial at some deep wells and long-term sustainability of the aquifer should be evaluated. PRACTITIONER POINTS: GenX concentrations decreased with increasing depth in four aquifers near a PFAS plant. A few exceedances of drinking water standards and health advisories were found in deep bedrock wells. New bedrock wells could be part of the response to PFAS issues in shallower wells. In the long term, deep bedrock wells might be a less expensive option for some residents.

Quantification of Nitrate Level in Shallow and Deep Groundwater Wells for Drinking, Domestic and Agricultural Uses in Northeastern Arid Regions of Saudi Arabia

Nitrate (NO3−) is a vulnerable natural contaminant that can be found in groundwater. The estimated nitrate concentrations for four categories of wells in the northeastern arid regions of Saudi Arabia—commercial treated water stations for drinking, commercial stations of untreated water for domestic uses, private wells of residences for households, and private wells for agricultural uses—were found to be in the 16–380 mg/L range. Drinking water from all commercial treated water stations has lower nitrate levels, based on the WHO standard of 50 mg/L. In contrast, almost 33% of commercial stations with untreated water (used only for domestic purposes) in the studied areas had higher nitrate levels that were unsuitable for drinking. Approximately half of the private wells of residences and wells for agricultural uses had very high nitrate levels. They can be considered unsuitable for drinking due to excessive levels of nitrates but can be used for domestic and agricultural purposes. Thus, adopting specific strategies to reduce nitrate levels in public wells in the studied areas is crucial. The data obtained in the present study are essential for equipping decision-makers with valuable insights, allowing them to enact appropriate measures, as needed, and uphold community health in the studied regions.

WATER RESOURCES OF THE KHOROSTKIV TERRITORIAL COMMUNITY: ECOLOGICAL STATUS, WATER USE PROBLEMS, OPTIMISATION MEASURES

The article analyses the ecological state of surface water resources of the Khorostkiv territorial community (ТС). According to the results of laboratory tests, pathogenic microorganisms, bacteriological indicators exceeding the regulatory requirements, faecal contamination and high content of organic matter were detected in the surface water bodies of the Khorostkiv TC. In addition to the pollution of surface water bodies in the Khorostkiv TC, an important environmental problem worth paying attention to is the lack of sanitary protection and water protection zones for rivers and ponds, as well as the littering of the coastal strip. It was found that the water supply network of the Khorostkiv territorial community includes only the water supply network of the town of Khorostkiv (30 km, unsatisfactory condition), since there are no centralised water supply systems in rural settlements. In the sources of centralised water supply in Khorostkiv, the levels of ammonium nitrogen and colour are exceeded. Hydrochemical analysis of water samples from private wells in Khorostkiv and the villages of Peremyliv and Khlopivka confirmed compliance with the requirements of SanR&amp;R № 400. The volume of daily water consumption and water disposal was analysed. The main sources of pollution of the community's water resources and the volume of wastewater discharges were identified. Priority areas for improving the ecological state of water resources of the Khorostkiv community are substantiated. Keywords: surface water, groundwater, pollutants, water supply, water disposal, territorial community (ТС).

Microparticles of arsenic water treatment media and water softener resin observed in treated water at private wells.

Observation of arsenic water treatment adsorption media in the treated water of several homes with high arsenic private wells led to the hypothesis that treatment media was escaping the treatment systems and entering the plumbing and drinking water. Our research at 62 homes identified that microparticles of arsenic water treatment media and/or water softener resin had escaped the treatment system in 71% of the homes. This is a potential health hazard as ingesting arsenic treatment media or water softener resin may lead to an elevated ingestion exposure to arsenic and other contaminants. Potential causes of media escape from the treatment systems include media observed to be smaller in size than specifications and media breaking into smaller pieces. One interim solution to media escape is installation of a post-treatment sediment filter. New developments in media durability or treatment system design and maintenance may be needed to prevent media escaping into drinking water. PRACTITIONER POINTS: Arsenic in private wells is often treated with point-of-entry whole house adsorption systems. Arsenic adsorption treatment media and/or water softener resin was observed in treated water at 44 of 62 homes inspected. Water treatment media escaping into treated water is a potential hazardous exposure pathway. Potential causes and solutions are discussed.

Drinking water sources, quality, and associated health outcomes in Appalachian Virginia: A risk characterization study in two counties

ObjectivesIn the US, violations of drinking water regulations are highest in lower-income rural areas overall, and particularly in Central Appalachia. However, data on drinking water use, quality, and associated health outcomes in rural Appalachia are limited. We sought to assess public and private drinking water sources and associated risk factors for waterborne pathogen exposures for individuals living in rural regions of Appalachian Virginia. MethodsWe administered surveys and collected tap water, bottled water, and saliva samples in lower-income households in two adjacent rural counties in southwest Virginia (bordering Kentucky and Tennessee). Water samples were tested for pH, temperature, conductivity, total coliforms, E. coli, free chlorine, nitrate, fluoride, heavy metals, and specific pathogen targets. Saliva samples were analyzed for antibody responses to potentially waterborne infections. We also shared water analysis results with households. ResultsWe enrolled 33 households (83 individuals), 82% (n = 27) with utility-supplied water and 18% with private wells (n = 3) or springs (n = 3). 58% (n = 19) reported household incomes of <$20,000/year. Total coliforms were detected in water samples from 33% (n = 11) of homes, E. coli in 12%, all with wells or springs (n = 4), and Aeromonas, Campylobacter, and Enterobacter in 9%, all spring water (n = 3). Diarrhea was reported for 10% of individuals (n = 8), but was not associated with E. coli detection. 34% (n = 15) of saliva samples had detectable antibody responses for Cryptosporidium spp., C. jejuni, and Hepatitis E. After controlling for covariates and clustering, individuals in households with septic systems and straight pipes had significantly higher likelihoods of antibody detection (risk ratios = 3.28, 95%CI = 1.01–10.65). ConclusionsTo our knowledge, this is the first study to collect and analyze drinking water samples, saliva samples, and reported health outcome data from low-income households in Central Appalachia. Our findings indicate that utility-supplied water in this region was generally safe, and individuals in low-income households without utility-supplied water or sewerage have higher exposures to waterborne pathogens.

Human Health Risk Assessment of Radionuclide Contamination in Drinking Water

This study investigates the human health risks of uranium, radium, radon, and other drinking water radionuclides and their mitigation strategies. It was implemented through literature review, field sampling, and analytical methods. Samples were taken from various sources, including groundwater, surface water, municipal supplies, and private wells. ICPI-MS and liquid scintillation counters were used for radiation measurements. Statistical analysis and risk assessment models were used to measure health risks and treatment effectiveness. Groundwater sources were the main sources of radionuclides, with private wells being the main sources. The elimination efficiencies of reverse osmosis were exceptional, reaching up to 99%. The elderly population (60+ years) were the most likely to have cancer, with the highest risks for bladder cancer, lung cancer, kidney cancer, and leukemia. The frequency of radionuclide contamination in drinking water sources varied, with the U.S. Environmental Protection Agency, Nigerian EPA, and Canada having the strictest schedules. The results emphasize the urgent need for monitoring programs, effective treatment technologies, and targeted risk management strategies to cope with radionuclide contamination. Government advice includes improving the regulatory system, developing advanced treatment methods, long-term epidemiological studies, public awareness, interdisciplinary collaboration, scientific exploration of alternative water sources, and prioritizing interventions for vulnerable populations.

How informal water supply points using private wells worked in an emergency: A quantitative evaluation

ABSTRACT The effectiveness of an emergency water supply using private wells has been asserted theoretically but not evaluated in detail. This paper aims to consider the effectiveness and shortcomings of emergency water supply based on local wells and to support policy formulation regarding groundwater usage in the event of a disaster. In Kamisu City, Ibaraki Prefecture, Japan, not only public-operated formal water supply points using water trucks but also informal water supply points using private wells were open to address water outages following the Great East Japan Earthquake of 2011. This study clarified the pattern of appearance and spatial distribution of those points by combining information from local newspapers, Internet archives, and an original questionnaire survey. In addition, the function of informal water supply points was quantitatively evaluated using GIS by comparing cases with and without informal water supply points. Analysis revealed that informal water supply points expanded the size of the serviced population within a 500-m radius of the water supply points by 47%, compared with cases when only formal water supply points were available. However, well water was not necessarily suitable for drinking owing to quality issues. As a policy lesson, the importance of sharing well information is indicated.

Association of Water Arsenic With Incident Diabetes in U.S. Adults: The Multi-Ethnic Study of Atherosclerosis and the Strong Heart Study.

We examined the association of arsenic in federally regulated community water systems (CWS) and unregulated private wells with type 2 diabetes (T2D) incidence in the Strong Heart Family Study (SHFS), a prospective study of American Indian communities, and the Multi-Ethnic Study of Atherosclerosis (MESA), a prospective study of racially and ethnically diverse urban U.S. communities. We evaluated 1,791 participants from SHFS and 5,777 participants from MESA who had water arsenic estimates available and were free of T2D at baseline (2001-2003 and 2000-2002, respectively). Participants were followed for incident T2D until 2010 (SHFS cohort) or 2019 (MESA cohort). We used Cox proportional hazards mixed-effects models to account for clustering by family and residential zip code, with adjustment for sex, baseline age, BMI, smoking status, and education. T2D incidence was 24.4 cases per 1,000 person-years (mean follow-up, 5.6 years) in SHFS and 11.2 per 1,000 person-years (mean follow-up, 14.0 years) in MESA. In a meta-analysis across the SHFS and MESA cohorts, the hazard ratio (95% CI) per doubling in CWS arsenic was 1.10 (1.02, 1.18). The corresponding hazard ratio was 1.09 (0.95, 1.26) in the SHFS group and 1.10 (1.01, 1.20) in the MESA group. The corresponding hazard ratio (95% CI) for arsenic in private wells and incident T2D in SHFS was 1.05 (0.95, 1.16). We observed statistical interaction and larger magnitude hazard ratios for participants with BMI <25 kg/m2 and female participants. Low to moderate water arsenic levels (<10 µg/L) were associated with T2D incidence in the SHFS and MESA cohorts.

Assessment of the suitability of greensand filtration for Mn removal for private wells

Greensand filtration is a common treatment option for manganese, sulfide, and iron removal; poor maintenance, however, can compromise effectiveness and even lead to increased post-treatment Mn concentrations. A private drinking-water well in exceedance of Health Canada’s maximum allowable concentration for Mn was sampled over a 1-year period to assess Mn removal via greensand filtration. Mn concentrations post-treatment were on average twofold higher than raw well water prior to media change. Reducing conditions, evidenced by negative oxidation–reduction potential (ORP) of the effluent, were central to generating soluble Mn(II). Monitoring revealed that water usage patterns caused variability in post-treatment Mn, with peak concentrations (&gt;3.5× higher than influent water) observed after a 7-day idle period. As inadequate oxidant addition can lead to reducing conditions, monitoring ORP may facilitate proxy surveillance for Mn release. Findings underscore the importance of human factors (e.g., aesthetic concerns, barriers to maintenance, perceived risk) when evaluating overall benefits and drawbacks of treatment systems.