Evaluation of lead release potential of new premise plumbing materials

Release of lead, copper, zinc from the initial corrosion of brass water meter in drinking water: Influences of solution composition and electrochemical characterization

Corrosion of brass plumbing materials may lead to metal release and deteriorate the drinking water quality. In this study, the initial corrosion of brass coupon cut from commercially available water meter was investigated. High rates of Pb, Cu and Zn release from the brass coupon were found during the early stage of corrosion (0-5 d) due to general corrosion and galvanic corrosion. The corrosion current density (Icorr) increased and resistance (RF) decreased during this period indicating that severe corrosion had occurred. In a later stage (5-30 d), a decreased Icorr and an increased RF were observed due to the development of a denser layer of Pb and Cu corrosion products which regulated the release of soluble Pb and Cu. The release of Zn continued and no significant Zn precipitation was found. Overall, particulate Pb, particulate Cu and soluble Zn dominated in the metal release during the initial corrosion of brass. The release of Pb, Cu and Zn was enhanced by a lower pH. Free chlorine was found to slightly reduce the release of Pb but promote the release of Cu and Zn. The presence of Pb on the brass surfaces was found to alleviate the dezincification process. A conceptual model based on metal release profile and electrochemical characterization was proposed to describe the initial corrosion of brass in typical drinking water.

Release of Particulate Lead from Four Lead Corrosion Products in Drinking Water: A Laboratory Study Coupled with Microscopic Observations and Computational Fluid Dynamics

Particulate lead resulting from the detachment of lead corrosion products (LCPs) contributes significantly to lead contamination in drinking water. Since LCPs formed under different water chemistry possesses different crystal structures, their hydrodynamic behaviors could be significantly different in flowing water. In this study, flushing experiments and microscopic observations were employed to investigate the release of cerussite (PbCO₃), hydrocerussite (Pb₃(CO₃)₂(OH)₂), chloropyromorphite (Pb₅(PO₄)₃Cl), and lead dioxide (scrutinyite α-PbO₂/plattnerite β-PbO₂), the four LCPs commonly found in the drinking water distribution system. Under the same flow rate, particulate lead release showed the following trend: lead dioxide > cerussite ∼ chloropyromorphite > hydrocerussite. In the range of 1-10 L/min, a higher flow rate enhanced the release of cerussite, chloropyromorphite, and lead dioxide, while the release of hydrocerussite was not significantly affected, likely due to its platelike crystal structure that reduced the shear force exerted by the flowing water. The detachments of visible cerussite and chloropyromorphite particles were captured using a digital microscope at flow rates of 8.0 and 8.2 L/min, and the shear forces causing their detachments were determined to be 5.8 × 10^-11 and 3.1 × 10^-10 N, respectively, using computational fluid dynamics (CFD). Our study demonstrated that crystal structure could be an important factor affecting the detachment of LCPs and CFD could be a useful tool to characterize their hydrodynamic behaviors.

Elevated water lead levels in schools using water from on-site wells

Only 8% of US public schools operate their own community water systems, and thus are subject to the federal Lead and Copper Rule's regulation of water lead levels (WLLs). To date, the absence of parallel water testing data for all other schools has prevented the comparison of WLLs with schools that do not face federal regulation. This study compiled and analyzed newly available school-level WLL data that included water source (on-site well water or public utility) and pipe material data for public schools in New York State located outside of New York City. Despite direct federal regulation, schools that used water from on-site wells had a substantially higher percentage of water fixtures with elevated WLLs. Schools that used both on-site well water and iron pipes in their water distribution system had the highest percentage of elevated fixtures. Variation in water treatment practices was identified as a potential contributing mechanism, as schools that used on-site well water were less likely to implement corrosion control. The study concluded that information about water source and premise plumbing material may be useful to policymakers targeting schools for testing and remediation.

Hidden toxins: bathtubs as a potential source of lead exposure in children

Exposure to lead (Pb) remains a serious health concern for children in the United States, particularly those residing in deteriorating housing. While some sources of Pb such as deteriorating paint and lead waterworks are relatively well understood and widely known, other sources remain hidden. One potential hidden source is bathtubs. In this experiment, water resting in a leaded bathtub was tested over a course of 60 min to determine the extent of metal leaching from the tub to the water. Lead levels in the water increased from 6.8 μg/L at baseline to 13 μg/L after resting in the tub for 60 min. Further research is needed to understand if this is typical, the contributing factors, and clinical significance of this finding.

Acid Precipitation and the Prevalence of Parkinson's Disease: An Ecologic Study in U.S. States

Although the etiology of Parkinson’s disease (PD) is unknown, potentially informative clues lie in its geographic distribution. PD prevalence rates within the U.S. are significantly higher in the Midwest and Northeast, a pattern that resembles the geographic distribution of acid precipitation (“acid rain”). Using linear and multivariable regression, we examined state-wide data on PD prevalence in relation to environmental factors including total precipitation, the acidity of precipitation, the use of well water, and industrial releases of sulfuric acid. In multivariate analyses, age-, race-, and gender-adjusted prevalence rates for PD were inversely correlated with well water use and positively correlated with industrial releases of sulfuric acid and with the quantity of acid precipitation (p < 0.0001). To our knowledge, this is the first report of an association between PD and acid rain. Because acid rain is known to leach metals from soils and pipes into drinking water, acid rain’s association with PD prevalence adds support for a role for metals in the etiology of PD.

A field survey on elution of lead and nickel from taps used in homes and analysis of product test results

The elution of lead, and nickel from water supply devices into water is a potential health concern. This study was performed to examine the actual concentrations of nickel and lead in the water from taps in homes and offices, focusing on the differences between first flush and fully flushed water. The water quality management target value and water quality standard in Japan specify nickel and lead concentrations in drinking water <20 and <10 μg/L, respectively. Nickel concentration in the first flush water (100 mL) from 110 household taps revealed 22 cases (20%) > 20 μg/L, while the fully flushed water satisfied the standard after running 5000 mL of water. The nickel concentration decreased gradually in sequential sampling of each 100 mL from the taps. Lead concentration in the first flush water exceeded the standard in 32 cases (29%), while the fully flushed water was below the target value. The concentration in the first flush water tended to decrease with time since the tap installation, and this was significant after 10 years for nickel but not significant for lead. It is important to flush retained water out of the tap after several hours without use. No significant correlation was found with the volume of the test faucet in the market, but bronze-based products showed higher nickel concentrations than brass and plastic products.

Ferrate(VI) pretreatment of water containing natural organic matter, bromide, and iodide: A potential strategy to control soluble lead release from PbO2(s)

Lead dioxide (PbO₂(s)) is a corrosion product of lead-containing plumbing materials in water distribution pipelines. The presence of reductants in water could cause the release of soluble lead (mainly Pb(II)) from PbO₂(s). Lead in drinking water is detrimental to public health. This paper presents the first application of ferrate (Fe^VIO₄^2-, Fe(VI)) to decreasing the generation of soluble lead in water containing PbO₂(s) and common reducing constituents (e.g., natural organic matter (NOM), iodide (I^-), and bromide (Br^-)) at different pH conditions (i.e., 6.0, 7.0, and 8.0). The released soluble lead from PbO₂(s) was found to be dominantly controlled by NOM in water, via the redox dissolution of PbO₂(s) and the reduction of PbO₂(s) by reducing moieties of NOM. The feasibility of both processes increased when pH decreased. The I^- and Br^- in water played minor roles in generating soluble lead. Fe(VI) reacted with reducing functional groups of NOM, as determined by ¹³C nuclear magnetic resonance spectroscopy. Water pretreatment with Fe(VI) inhibited the reaction of NOM with PbO₂(s) and therefore, caused lower soluble lead concentrations compared to water samples without Fe(VI) treatment. This study indicates that Fe(VI) pretreatment is a potential approach to controlling soluble lead in drinking water.

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

Children who rely on private well water in the United States have been shown to be at greater risk of having elevated blood lead levels. Evidence-based solutions are needed to prevent drinking water lead exposure among private well users, but minimal data are available regarding the real-world effectiveness of available interventions like point-of-use water treatment for well water. In this study, under-sink activated carbon block water filters were tested for lead and other heavy metals removal in an eight-month longitudinal study in 17 homes relying on private wells. The device removed 98% of all influent lead for the entirety of the study, with all effluent lead levels less than 1 µg/L. Profile sampling in a subset of homes showed that the faucet fixture is a significant source of lead leaching where well water is corrosive. Flushing alone was not capable of reducing first-draw lead to levels below 1 µg/L, but the under-sink filter was found to increase the safety and effectiveness of faucet flushing. The results of this study can be used by individual well users and policymakers alike to improve decision-making around the use of under-sink point-of-use devices to prevent disproportionate lead exposures among private well users.

Lead release in drinking water resulting from galvanic corrosion in three-metal systems consisting of lead, copper and stainless steel

Lead pipe has been banned in the drinking water distribution system in most countries since 1980s. Although water authorities around the world have attempted to replace all remaining lead pipes in service, pipe replacement was often hindered by high cost and lack of access to private premises. Hence, partial replacement has become a common scenario where portions of lead pipes remain in the system. When the lead pipe is connected to two other different metallic materials at both ends, two different galvanic couples can form simultaneously in this three-metal system. The release of lead resulting from galvanic corrosion in such three-metal systems consisting of lead (Pb), copper (Cu) and stainless steel (SS) with three different configurations, namely Cu-SS-Pb, SS-Cu-Pb and Cu-Pb-SS was investigated in this study. The results showed that when the materials are arranged in order of reduction potential as in SS-Cu-Pb configuration, lead release was the highest. A more fluent electron transport across the system was proposed based on the direction and magnitude of galvanic currents measured at each galvanic couple.

Highly selective rapid colorimetric sensing of Pb2+ ion in water samples and paint based on metal induced aggregation of N-decanoyltromethamine capped gold nanoparticles

Lead is highly toxic. The detection of lead in the environmental bodies is difficult, because it is colourless and odourless. Herein, we report the synthesis of gold nanoparticles (AuNPs) using the interdigitized vesicles formed by N-decanoyltromethamine (NDTM). AuNPs stabilized by NDTM was pink in colour with spherical shape and the size is 29 ± 7 nm. The optical property of the NDTM-AuNPs was explored for the first time to detect toxic chemical, Pb²⁺. The addition of toxic metal ion Pb²⁺ to NDTM-AuNPs rapidly (< 1 min) alters the colour from pink to violet due to aggregation, which was confirmed by particle size analyser and TEM. The aggregation induced colour changes were realized via broad spectra in UV-Vis spectroscopy. NDTM-AuNPs showed a selective and sensitive spectrophotometric signal with Pb²⁺ when compared with other metal ions. The colorimetric change as a function of Pb²⁺ concentration gave a linear response in the range of 0-30 μM (R² = 0.9942). The detection limit was found at 10 μM by naked eye and 0.35 μM by spectrophotometry. The proposed method was successfully applied for the determination of Pb²⁺ ions in tap water and sewage water. Moreover, as a proof of concept, the NDTM-AuNPs sensor system was applied for the detection of lead in commercial paints. The results of the quantitative estimation of lead in paints by NDTM-AuNPs colorimetric sensor were as good as the standard method, atomic absorption spectroscopy.

Survey of lead concentration in tap water on a university campus

In this study, a sampling campaign was conducted for 29 buildings on the National Taiwan University (NTU) campus where lead pipes were present in 4 buildings. Total lead, soluble lead, and water quality parameters including pH, temperature, residual free chlorine, and total organic carbon were measured. Results from the first-round sequential sampling (10 × 100 mL) showed that the presence of lead pipe did not necessarily cause elevated lead levels. However, the highest lead concentration and the highest frequency of exceeding 10 μg/L were detected in a building with lead pipe. Faucet was identified to be a major lead source in at least 8 buildings. No significant correlations between lead levels and water parameters were found. The building showing the highest lead level in the first round was sampled for a second round using four different methods, namely, first draw sampling, random daytime sampling, sequential sampling (5 × 1 L), and flushing sampling. Lead levels in samples collected using the four sampling methods all exceeded 10 μg/L. The first draw sampling showed the highest lead level, followed by comparable levels for random daytime sampling and sequential sampling. Flush sampling yielded the lowest lead concentration. Particles collected from the faucet aerators in 14 buildings were also characterized for their compositions and lead contents.