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Lead (Pb) in Tap Water and in Blood: Implications for Lead Exposure in the United States
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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... This raises concern about its toxic effects on public health. Excessive levels of lead intake can cause brain impairment and have been linked to cancers in kidneys, lungs and brain [1][2][3]. Therefore, systematic protocols were introduced for protection and its maximum allowable limit in water is set at 10 μg/l [4]. Detection of trace amounts of lead in food and biological samples is also becoming an increasingly important area of research for this reason. ...
... Developing accurate methods for its selective determination, especially at trace levels, is becoming a major problem nowadays. Several traditional techniques can be very sensitive and selective [3,4]. However, most of these techniques are costly, time-consuming and lack on-site monitoring. ...
... In the United States, Pb is one of the most significant environmental health risks, and there are increasing concerns regarding health hazards at the levels of exposure that were previously deemed safe [79], even with a drastic decline in public and local use over the past decades. Several pieces of Pb-related legislation have been passed by the US Congress, regulating Pb levels for commercial and residential purposes in paint, dust and soil, water and the handling of lead wastes [47] owing to substantial evidence from scientific research which has found that the even low levels of Pb exposure are still largely unsafe for human health. ...
... The Environmental Protection Agency, which is saddled with the responsibility of protecting human These regulations were enacted to guard individuals and families in the United States against Pb exposure as a public health priority with Part 35 of the Title X authorizing the HUD and EPA to demand disclosure of adequate information on hazardous effects of leadbased paints prior to the sale or lease of houses developed before 1978 [81]. Additionally, the CWA as amended in 1972 prohibits discharge of contaminants with Pb inclusive into waterways and regulates industrial waste discharge and prescribed standards for sewer systems [82], and the SWDA, which applies to all public water systems with the aim of enhancing the safety of water which the general public consumes, aims to optimize the nation's water supply to ensure safe, public consumption [79,83], while Title 40 of the Lead and Copper Rule monitors the exposure of individuals to Pb through drinking water while safeguarding public health and ensuring that Pb concentration levels do not exceed 0.015 µg/L [84,85]. The CAA regulates the amount of Pb that can be in outdoor air, restricting pollutant emissions from industries and was responsible for the final ban of leaded gasoline following a couple of amendments [83]. ...
The health and life outcomes of individuals are intertwined with the context in which they grow and live. The totality of exposures one experiences affects health in the short term and throughout the life course. Environmental exposure to multiple contaminants can increase stress levels in individuals and neighborhoods with psychosocial stressors such as crime, drug and alcohol misuse, and violence also taking a toll on individual and neighborhood wellbeing. In addition, the availability, organization, and quality of local institutions and infrastructure all affect health in the short and long term. The role of these factors in endometrial cancer will be explored in this paper. In addition, policy implications regarding lead, chronic physiological stress, and endometrial cancer will be explored to ascertain the impact of these factors on at-risk women.
... Testing household drinking water for lead is important in efforts to reduce lead exposure in households. Water lead levels (WLLs) can vary among homes within a community due to betweenhome differences in the presence, type, and condition of lead service lines, and of lead-containing plumbing fixtures in homes [1][2][3]. Even at the kitchen tap of an individual home, elements of water sampling protocolssuch as the flow rate, duration of water stagnation prior to sampling, and the volume that flows from the tap prior to collecting the water sample can impact WLL, as can water temperature, and seasonality [3][4][5][6]. ...
... If WLLs in a given home never varied, a single sample would be sufficient to characterize lead levels (assuming no measurement error). However, prior studies have noted that the intermittent release of lead particulates from plumbing or well components renders the collection of single water samples of limited value in characterizing the health risks faced by building occupants [1,2,11,19]. We found that in the scenario of 2% of homes having a spike on the first round of water sampling and the midrange set of transitional probabilities, approximately 50% of homes have undetectable lead levels, 48% have detectable levels without a spike caused by particulate release, yet if all homes underwent 15 rounds of sampling, spikes of particulate lead release would be identified in 31.7% of homes (Table 5). ...
Background
Lead can be present in drinking water in soluble and particulate forms. The intermittent release of lead particulates in drinking water can produce highly variable water lead levels (WLLs) in individual homes, a health concern because both particulate and soluble lead are bioavailable. More frequent water sampling would increase the likelihood of identifying sporadic lead “spikes,” though little information is available to aid in estimating how many samples are needed to achieve a given degree of sensitivity to spike detection.
Objective
To estimate the number of rounds of tap water sampling needed to determine with a given level of confidence that an individual household is at low risk for the intermittent release of lead particulates.
Methods
We simulated WLLs for 100,000 homes on 15 rounds of sampling under a variety of assumptions about lead spike release. A Markovian structure was used to describe WLLs for individual homes on subsequent rounds of sampling given a set of transitional probabilities, in which homes with higher WLLs at baseline were more likely to exhibit a spike on repeated sampling.
Results
Assuming 2% of homes had a spike on the first round of sampling and a mid-range estimate of transitional probabilities, the initial round of sampling had a 6.4% sensitivity to detect a spike. Seven rounds of sampling would be needed to increase the sensitivity to 50%, which would leave unrecognized the more than 15,000 homes that intermittently exhibit spikes.
Significance
For assessing household risk for lead exposure through drinking water, multiple rounds of water sampling are needed to detect the infrequent but high spikes in WLLs due to particulate release. Water sampling procedures for assessment of lead exposure in individual homes should be modified to account for the infrequent but high spikes in WLL.
Impact
It has been known for decades that intermittent “spikes” in water lead occur due to the sporadic release of lead particulates. However, conventional water sampling strategies do not account for these infrequent but hazardous events. This research suggests that current approaches to sampling tap water for lead testing identify only a small fraction of homes in which particulate spikes occur, and that sampling procedures should be changed substantially to increase the probability of identifying the hazard of particulate lead release into drinking water.
... Plastic pipe surfaces are generally exposed to Pb concentrations above the US Environmental Protection Agency (USEPA) action level (>15 μg L − 1 ). This exposure could be under stagnant water conditions, elevated temperatures, or pressurized conditions that might impact adsorption (Triantafyllidou and Edwards, 2012). Systematic research is needed to identify how heavy metal uptake by plastic pipes differs from pellets, which have been studied extensively (Holmes et al., 2012(Holmes et al., , 2014Huang et al., 2020), to better understand their fate in the built environment. ...
Heavy metals' interactions with plumbing materials are complicated due to the differential formation of biofilms within pipes that can modulate, transform, and/or sequester heavy metals. This research aims to elucidate the mechanistic role of biofilm presence on Lead (Pb) accumulation onto crosslinked polyethylene (PEX-A), high-density polyethylene (HDPE), and copper potable water pipes. For this purpose, biofilms were grown on new pipes for three months. Five-day Pb exposure experiments were conducted to examine the kinetics of Pb accumulation onto the new and biofilm-laden pipes. Additionally, the influence of Pb initial concentration on the rate of its accumulation onto the pipes was examined. The results revealed greater biofilm biomass on the PEX-A pipes compared to the copper and HDPE pipes. More negative zeta potential was found for the biofilm-laden plastic pipes compared to the new plastic pipes. After five days of Pb exposure under stagnant conditions, the biofilm-laden PEX-A (980 μg m-2) and HDPE (1170 μg m-2) pipe accumulated more than three times the Pb surface loading compared to the new PEX-A (265 μg m-2) and HDPE pipes (329 μg m-2), respectively. However, under flow conditions, Pb accumulation on biofilm-laden plastic pipes was lower than on the new pipes. Moreover, with increasing the initial Pb concentration, greater rates of Pb surface accumulation were found for the biofilm-laden pipes compared to the new pipes under stagnant conditions. First-order kinetics models best described the Pb accumulation onto both new and biofilm-laden water pipes under both stagnant and flow conditions.
... Replacement of about 80% of lead pipe with copper pipe, in Canada, caused sustained lead release (sometimes worse than a full lead system) up to 12 weeks upon substitution [30]. The same behaviour has been reported in the USA [31]. This was attributed to galvanic corrosion between aged lead pipes and new copper pipes [30,32]. ...
The inner walls of drinking water distribution system (DWDS) are expected to be clean to ensure a safe quality of drinking water. In reality, complex physical, chemical and biological processes take place when water comes into contact with the pipe surface. This paper describes the impact of leaching different compounds from the water supply pipes into the drinking water and subsequent risks. Among these compounds there are heavy metals. It is necessary to prevent these metals to get into the DWDS. Those compounds are susceptible to impact the quality of the water delivered to population either by leaching dangerous chemicals into the water or by enhancing the development of microorganism growth on the pipe surface. The corrosion process of different pipes materials, scale formation mechanisms and the impact of bacteria formed in corrosion layers are discussed. Water treatment processes and the pipe materials also affect the water composition. Pipes materials act differently in the flowing and stagnation conditions. Also, they age differently (e.g metal based pipes are subjected to corrosion while polymer based pipes have a decreased mechanical resistance) and are susceptible to enhance bacterial film formation. This review helps to clarify what are the possible sources of compounds responsible for drinking water quality degradation. Also, it gives guidance on the measures that are needed to maintain a stable and safe drinking water quality.
Lead exposure is a persistent environmental hazard that poses risks to human health. But motivating protective action is challenging with this low visibility hazard whose health effects are often subtle and chronic. Higher risk perception is generally associated with taking protective measures, so public health efforts prioritize risk messaging. Yet, little is known about perceptions of lead exposure risk among the U.S. public. Using cross‐sectional data from a national survey of 1035 U.S. residents, we measured the role of trust in government management of lead and subjective knowledge about lead as predictors of perceived risk of lead exposure, controlling for demographic and environmental factors. We also assessed if subjective knowledge moderated the relationship between trust and perceived risk. Our results reveal positive relationships between trust in government management of lead, subjective knowledge about lead, and risk perception, which we attribute in part to the important role government agencies play in secondary prevention, or communicating the risks of environmental lead exposure. We also found that younger people and people living in a house built before lead paint regulations passed in 1978 perceived higher lead risks. Our findings suggest that general communication about lead risks should aim to increase people's subjective knowledge in a consistent and balanced way that improves trust in government messengers.
Galvanized iron pipe (GIP) was once widely installed in publicly and privately owned potable water systems. This antiquated plumbing material can cause water discoloration from iron release, head loss resulting from corrosion scale buildup, and occasional problems with lead (Pb) release to drinking water. In this work, a GIP management framework for utilities is formulated via a literature review and several case studies. The GIP management plan is intended to guide water systems with understanding and addressing GIP issues while considering consumer expectations, corrosion control challenges, variable performance, and associated cost–benefit analysis for corrective actions.
To better understand water security of communities in North Carolina, this research uses structural topic modeling (STM) and geographic mapping to identify the main topics and pollutant categories being researched and the areas exposed to drinking water contaminants. The textual data derived from the journal article abstracts that examined water pollution in North Carolina is from 1964 to present. The STM analysis of textual data is paired with socio-demographic data from the 2015-2019 American Community Survey (ACS) 5-year estimates and water pollution data from North Carolina state agencies. The STM findings show that the most discussed topics relate to runoff management, wastewater from concentrated agricultural feeding operations, emerging contaminants, land development, and health impacts as a result of water contamination. The article discusses how the topics especially threaten groundwater resources used by community water systems and private wells. Those communities served by private wells are predominantly low-income and minority populations. As a result, threats to groundwater supplies exacerbate existing issues of environmental justice in North Carolina, especially in the Coastal Plains Region. The STM findings revealed that several key threats to safe drinking water are less covered by academic literature, such as poultry concentrated agricultural feeding operations and climate impacts, which may increase disparities in water access in North Carolina.
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.