Under-Sink Activated Carbon Water Filters Effectively Remove Lead from Private Well Water for over Six Months

Effect of Community Water Service on Lead in Drinking Water in an Environmental Justice Community

Multiple recent studies have found elevated lead (Pb) concentrations in tap water in U.S. homes relying on unregulated private wells. The main Pb source is dissolution from household plumbing, fixtures, and well components. Here, we leverage a natural experiment and citizen science approach to evaluate how extending community water service to an environmental justice community relying on private wells affects Pb in household water. We analyzed Pb in 260 first-draw kitchen tap water samples collected by individual homeowners over a 5-month period in residences that did and did not connect to the community system. Before the community water system was extended, 25% of homes had Pb > 15 μg/L (the U.S. regulatory action level for community water systems) in first-draw water samples. Pb was significantly correlated with nickel (ρ = 0.61), zinc (ρ = 0.50), and copper (ρ = 0.40), suggesting that corrosion of brass fittings and fixtures is the main Pb source. Among homes that connected to the community system, Pb decreased rapidly and was sustained at levels well below 15 μg/L over the study period. Overall, connecting to the municipal water supply was associated with a 92.5% decrease in first-draw tap water Pb.

Faucet-mounted point-of-use drinking water filters to improve water quality in households served by private wells

Approximately 13 % of Americans rely on private wells for household potable water. As private wells are not regulated beyond initial construction and often employ limited or no treatment, source water from wells can be vulnerable to contamination. While several studies have assessed applications of point-of-use (POU) filters in improving municipal tap water quality, few have investigated their use with private well water. This effort aims to build on previous examinations of POU treatment as a strategy to reduce adverse household drinking water exposures by: 1) assessing the effectiveness of commercially available faucet-mounted POU filters for improving microbial and chemical water quality in homes with private wells; and 2) documenting household ease of use and satisfaction with the filters. Faucet-mounted POU filters were distributed to 21 homes reliant on private wells in southern West Virginia and southwestern Virginia. Study participants were asked to collect water samples from two taps in their homes pre-filter installation, and again two-weeks and four-weeks post-installation. Participants filled out surveys about perceptions of their drinking water and the filter. Concentrations of Total Coliform, Ba, Cd, Cr, U, Cu, Pb, Al, Fe, Mn, Zn, and Sr were significantly lower (p < 0.05, Wilcoxon Rank Sum) in filtered water samples compared to paired unfiltered samples (n = 42) for the study period. However, concentrations of certain contaminants in filtered samples from homes with high levels of source water contamination still exceeded drinking water standards. Less than half of study participants reported that they intended to keep using the filters, citing issues of flowrate. Our findings suggest that faucet-mounted POU filters, while effective in reducing contaminants, might not be an appropriate intervention to improve water quality for all homes on private well water. Future investigation is required to improve filter user satisfaction and better assess appropriate source water chemistries for implementation.

Reviewing performance of NSF/ANSI 53 certified water filters for lead removal

Properly certified NSF/ANSI 53 water filters are distributed as a temporary measure to protect residents from risk of exposure to elevated lead (Pb) levels resulting from water system changes and various activities. Water consumers and other stakeholders have raised questions on the performance of these filters in field settings, particularly in cases where water Pb levels exceeded the NSF/ANSI 53 challenge water level of 150 µg/L and when Pb phosphate nanoparticles (≤ 200 nm) were present in drinking water. This literature review summarizes findings from 23 studies that evaluated the ability of NSF/ANSI 53 post-2007 certified filters to reduce soluble and/or particulate Pb from water. The studies in total examined 1,486 faucet-mounted, 25 under-the-sink, and 167 pitcher filters, with 1,528 filters used in field studies and 150 filters in laboratory studies. This review found that filter performance varied with different filter type, test water source, and initial unfiltered total Pb concentration. 99% (1,512/1,528) of the filters used in field studies removed Pb to at or below the certification benchmark of pre-2019, 10 µg/L or post-2019, 5 µg/L. In contrast, 61% (91/150) of the filters used in laboratory studies reduced Pb to the benchmark. Laboratory filters were often tested under conditions beyond what they were certified to handle. Pb concentration, particle form and size, improper operation and maintenance of certified water filters were attributed to reported filter failures. This information is intended to help water utilities, regulators, and others make decisions regarding the deployment of water filters to the public when drinking water Pb exposure concerns have been raised.

Lead Levels in Tap Water at Licensed North Carolina Child Care Facilities, 2020-2021

Objectives. To evaluate lead levels in tap water at licensed North Carolina child care facilities. Methods. Between July 2020 and October 2021, we enrolled 4005 facilities in a grant-funded, participatory science testing program. We identified risk factors associated with elevated first-draw lead levels using multiple logistic regression analysis. Results. By sample (n = 22 943), 3% of tap water sources exceeded the 10 parts per billion (ppb) North Carolina hazard level, whereas 25% of tap water sources exceeded 1 ppb, the American Academy of Pediatrics' reference level. By facility, at least 1 tap water source exceeded 1 ppb and 10 ppb at 56% and 12% of facilities, respectively. Well water reliance was the largest risk factor, followed by participation in Head Start programs and building age. We observed large variability between tap water sources within the same facility. Conclusions. Tap water in child care facilities is a potential lead exposure source for children. Given variability among tap water sources, it is imperative to test every source used for drinking and cooking so appropriate action can be taken to protect children's health. (Am J Public Health. 2022;112(S7):S695-S705. https://doi.org/10.2105/AJPH.2022.307003).

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

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

Early life lead exposure from private well water increases juvenile delinquency risk among US teens

Public health agencies worldwide have determined that there is no safe level for children’s exposure to lead, a neurotoxin. This study shows that lead in drinking water from private wells is significantly associated with juvenile delinquency. Compared to children in homes with public water supplies, those relying on private wells have a 21% higher risk of any delinquency and a 38% increased risk of serious delinquency. The steepest increases in risk occur at the lowest exposure levels. The results highlight the need to prevent lead-leaching from well components, plumbing, and fixtures in the 13% of US households relying on private wells. They also suggest the need to decrease blood and environmental lead thresholds currently used to identify at-risk children.

Early life exposure to environmental lead (Pb) has been linked to decreased IQ, behavior problems, lower lifetime earnings, and increased criminal activity. Beginning in the 1970s, limits on Pb in paint, gasoline, food cans, and regulated water utilities sharply curtailed US environmental Pb exposure. Nonetheless, hundreds of thousands of US children remain at risk. This study reports on how unregulated private well water is an underrecognized Pb exposure source that is associated with an increased risk of teenage juvenile delinquency. We build a longitudinal dataset linking blood Pb measurements for 13,580 children under age 6 to their drinking water source, individual- and neighborhood-level demographics, and reported juvenile delinquency records. We estimate how early life Pb exposure from private well water influences reported delinquency. On average, children in homes with unregulated private wells had 11% higher blood Pb than those with community water service. This higher blood Pb was significantly associated with reported delinquency. Compared to children with community water service, those relying on private wells had a 21% (95% CI: 5 to 40%) higher risk of being reported for any delinquency and a 38% (95% CI: 10 to 73%) increased risk of being reported for serious delinquency after age 14. These results suggest that there could be substantial but as-yet-unrecognized social benefits from intervention programs to prevent children’s exposure to Pb from private wells, on which 13% of the US population relies.

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

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