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Lead (Pb) in Tap Water and in Blood: Implications for Lead Exposure in the United States
Critical Reviews In Environmental Science and Technology
Abstract and Figures
Lead is widely recognized as one of the most pervasive environmental health threats in the United States, and there is increased concern over adverse health impacts at levels of exposure once considered safe. Lead contamination of tap water was once a major cause of lead exposure in the United States and, as other sources have been addressed, the relative contribution of lead in water to lead in blood is expected to become increasingly important. Moreover, prior research suggests that lead in water may be more important as a source than is presently believed. The authors describe sources of lead in tap water, chemical forms of the lead, and relevant U.S. regulations/guidelines, while considering their implications for human exposure. Research that examined associations between water lead levels and blood lead levels is critically reviewed, and some of the challenges in making such associations, even if lead in water is the dominant source of lead in blood, are highlighted. Better protecting populations at risk from this and from other lead sources is necessary, if the United States is to achieve its goal of eliminating elevated blood lead levels in children by 2020.
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... Contamination due to metals is another well-known drinking water safety challenge, often caused by corrosion of pipes and fixtures and/or inadequate corrosion control in the presence of corrosive source waters [55,67]. Lead was detected (and exceeded its health benchmark of 0) in samples from all three drinking water options, though only in one BW sample. ...
Understanding drinking water quality at the point-of-use across a range of consumer options is essential for designing effective public health interventions in the face of deteriorating source waters and complex contaminant mixtures. This is especially pressing as the popularity of tap water alternatives like bottled water and household treatment increases, yet this data is largely missing from the academic literature and policy discussions. This study presents one of the first evaluations of water quality comparing three common consumer drinking water options in the nine county San Francisco Bay Area with a survey of 100 analytes in 100 bottled water samples, 603 tap water samples, and 111 samples of household-treated tap water. Analytes measured included general water quality characteristics, metals, other inorganics, volatile organic compounds (including disinfection byproducts), and three microbial indicator species in bottled water only. Samples were evaluated to assess potential taste, odor, and color issues, as well as potential health risks by calculating cumulative toxicity quotients to reflect the additive toxicity of chemical mixtures. All three drinking water options had potential health risks, primarily driven by the presence of trihalomethanes (contributing from 76.7 to 94.5% of the total cumulative toxicity across the three drinking water options). While tap water had the highest potential toxicity among the three drinking water options, results suggest that household-scale treatment may reduce the potential for aesthetic issues and health risks of tap water.
Galvanic corrosion of lead–tin solder in copper plumbing can be a major contributor to water lead contamination. Here, we report the electrochemical reversal of the copper-solder galvanic couple, in which the normally anodic solder becomes cathodic to copper via a reaction with free chlorine. This reversal occurred after a few months of exposure to continuously circulating water with relatively low pH and low alkalinity, causing dramatically decreased lead release and the formation of a Pb(IV) scale. Chloramine did not similarly inhibit solder corrosion over the 4–9 month test duration, resulting in up to 100 times more lead contamination of the water relative to free chlorine. These findings have major implications for corrosion control and public health and can help explain anomalously low levels of lead contamination in some waters with free chlorine that are normally considered corrosive to solder.
Lead in drinking water can lead to serious health effects, including neurodevelopmental issues and heart disease. In December 2023, the U.S. Environmental Protection Agency (EPA) proposed the Lead and Copper Rule Improvements (LCRI), which lower the Lead and Copper Rule's (LCR's) lead action level (AL) from 15 parts per billion (ppb) to 10 ppb and require both first‐ and fifth‐liter sampling and 90th percentile compliance calculations based on the highest lead levels at sites with lead service lines. A methodology for estimating the likelihood a system will have an AL exceedance (ALE) under the LCRI was developed using Michigan LCR compliance data and applied to national LCR compliance data. Findings were compared to EPA's estimates, indicating EPA may have underestimated the percent of smaller systems (serving 3300) with ALEs and overestimated the percent of larger systems (serving > 10,000), thus underestimating costs and overestimating the benefits of this rulemaking.
Anthropogenic lead pollution remains a serious environmental concern due to the high incidence of human exposure worldwide and its severe health impact, particularly to children. We report a device-free colorimetric sensor for lead(II) ions in water based on the microdrop detection of the lead(II) rhodizonate complex trapped into a solid-solution of cellulose paper. This allows for the selective colorimetric detection of Pb²⁺ with a qualitative and quantitative detection limit of ~ 1 ppm. Comparative studies with Li⁺, Na⁺, K⁺, Ca²⁺, Mg²⁺, Sr²⁺, Ba²⁺, Cd²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Fe²⁺, Hg²⁺, Co²⁺, Ce²⁺, Mn²⁺, Cr²⁺, Cr²⁺, and Au³⁺ show high detectability for Pb²⁺ due to the unique charge transfer band present in the kinetically trapped Pb-RA complex. We demonstrated that without the solid-solution matrix, the lead(II) rhodizonate complex polymerizes into an extended solid. The mechanism and kinetics of Pb²⁺ detection were studied by UV-visible spectroscopy, XRD, transmission electron microscope (TEM), and dynamic light scattering analysis (DLS). This device-free sensing method for Pb²⁺ is highly portable and suitable for applications on the field.
Graphical Abstract
DSDA simultaneously down-converts ultraviolet light and enhances the conductivity of SnO 2 ; DSDA effectively passivates defects at the SnO 2 /perovskite interface while providing in situ protection against lead leakage.
Lead contamination of potable water in new buildings on the University of North Carolina at Chapel Hill campus was traced to corrosion of inline brass plumbing devices. Commissioning procedures to remove lead sediment and hasten brass passivation were developed. Forensic evaluation of a water fountain dispensing > 100 μg/L lead in flushed water after commissioning led to the discovery of ball valves containing brass with > 8% lead by weight on exterior surfaces and > 18% on surfaces contacting the water. Removing these ball valves resolved the lead problems, bench-testing verified that the valves had a high lead-leaching propensity, and subsequent surveying of ball valves in three buildings found 22% contained exterior surface lead > 8%. Significant lead-leaching problems can occur when: (1) the water is at least moderately corrosive to brass, (2) brass with a high lead content is present, and (3) premise plumbing lines have relatively low water demand.
Discusses what constitutes a satisfactory sample and the various factors which contribute to plumbosolvency. Concludes that treatment alone will not be 100% successful in reducing plumbosolvency to a satisfactory level for all plumbing situations, and that a large number of factors can contribute to lead concentration in water samples taken from taps and a number of these factors will probably not respond to water treatment. -R.House
As part of a study which attempted to determine whether there is a relationship between lead levels in drinking water and lead levels in blood, water samples were collected at 383 households in three Massachusetts cities and analyzed for trace metals to determine the extent of contamination resulting from the corrosion of piping materials. A report of water analysis and field observations related to water that were made during the study is presented.
• Under circumstances of low prenatal exposure to lead and low nondietary exposure to lead postnatally, four breast-fed infants and 25 formula-fed infants were studied to determine the relation between dietary intake of lead and blood lead concentration. From 8 through 111 days of age, the mean dietary intake of lead by the formula-fed infants was 17 μg/day (3 to 4 μg/kg/day), and intake of lead by the breast-fed infants was estimated to be only slightly greater. The mean blood lead concentration at the age of 112 days was 6.1 μg/dL. From 112 through 195 days of age, 17 infants continued in the study: ten received a mean dietary intake of lead of 16 μg/day, and seven received a mean intake of 61 μg/day. At 196 days of age, mean blood lead concentrations were significantly different (7.2 and 14.4 μg/dL, respectively).
(Am J Dis Child 1983;137:886-891)
This presentation will address lead in drinking water in the context of public health agencies' policies and practices for responding to and preventing childhood lead poisoning, as well as relevant guidance that the Centers for Disease Control and Prevention (CDC) provides or should provide to state and local lead poisoning programs. The presentation will look at why lead-contaminated drinking water is often overlooked as a potentially significant exposure source. The CDC's current shift toward promoting a holistic approach to preventing disease and injuries from hazards in the home provides a new opportunity for public health agencies to incorporate lead-in-water testing in their environmental risk assessments at the homes of children with elevated blood lead levels and to more intensively monitor water lead levels in their jurisdictions. The presentation also will discuss what some US cities and states have already done to address drinking water as a potential lead exposure source and practical steps that other jurisdictions could take to address this issue.
Lead contamination of potable water in new buildings on the University of North Carolina at Chapel Hill campus was traced to corrosion of inline brass plumbing devices. Commissioning procedures to remove lead sediment and hasten brass passivation were developed. Forensic evaluation of a water fountain dispensing > 100 μg/L lead in flushed water after commissioning led to the discovery of ball valves containing brass with > 8% lead by weight on exterior surfaces and > 18% on surfaces contacting the water. Removing these ball valves resolved the lead problems, bench-testing verified that the valves had a high lead-leaching propensity, and subsequent surveying of ball valves in three buildings found 22% contained exterior surface lead > 8%. Significant lead-leaching problems can occur when: (1) the water is at least moderately corrosive to brass, (2) brass with a high lead content is present, and (3) premise plumbing lines have relatively low water demand.