Lead and copper release from full and partially replaced harvested lead service lines: Impact of stagnation time prior to sampling and water quality

Biomimetic mineralization of hydrated magnesium carbonate for hydrogel reinforcement and heavy metal adsorption

With excessive Mn(Ⅱ) and Cu(Ⅱ) pollution in aquatic environments posing potential health risks to inhabitants, the emergence of carbon capture, utilization and storage (CCUS) technology has promoted the improvement of heavy metal remediation technologies. Using hydrothermal sediment as a crystal seed, rhamnolipid was used to mediate biomimetic mineralization to prepare hydrated magnesium carbonate (HMC) composites to enhance the Mn(Ⅱ)/Cu(Ⅱ) adsorption performance of alginate hydrogels. Hydrothermal sediment is beneficial for accelerating biomimetic mineralization, while rhamnolipid can induce a crystalline phase transformation from dypingite to nesquehonite. The addition of sediment significantly enhanced the compressive mechanical properties and thermal stability of the hydrogels. The adsorption performances of the nesquehonite and dypingite hydrogels were better for Mn(II) and Cu(II), respectively. An increase in the amount of sediment improved the adsorption of Cu(II) by the hydrogels appropriately, resulting in stronger selectivity for Cu(II). The adsorption of Mn(II) and Cu(II) on the hydrogel beads was thermodynamically spontaneous. The inhibitory effects of sodium dodecyl benzene sulfonate (SDBS), fulvic acid (FA) and alginate on Cu(II) adsorption were more obvious than those of bovine serum albumin (BSA). Both the complexation of functional groups on alginate and mineralization by HMC participated in the adsorption of Mn(II) and Cu(II).

Repeated home drinking water sampling to improve detection of particulate lead spikes: a simulation study

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.

Trace elements in hair or fingernail and gastroesophageal cancers: results from a population-based case-control study

BACKGROUND

Growing evidence suggests that environmental factors probably play important roles in the development of gastroesophageal cancers (GOC), however, the effects of trace elements on GOC remain unclear.

OBJECTIVE

To assess the effect of trace elements on GOC and the effect modification by other factors.

METHODS

Hair and fingernail samples were collected from GOC cases and controls in a population-based case-control study in Taixing, China, and were used to detect the concentrations of 12 trace elements using inductively coupled plasma mass spectrometry. Unconditional logistic regression models were used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) for concentrations of 12 trace elements in association with GOC after adjusting the other factors.

RESULTS

A total of 830 hair samples (581 controls and 249 cases) and 895 fingernail samples (559 controls and 336 cases) were included. Compared to the lowest-tertile concentration, the higher tertiles of Ca, Zn, Fe, Al, Cr, Pb, Se, and V were positively associated with GOC, while the higher tertiles of Mg, Mn, Sr, and As were inversely associated with GOC. Significant interactions between the hair level of Cr and two other risk factors, including smoking (P for interaction = 0.044) and alcohol drinking (P for interaction = 0.028), were observed in association with GOC.

SIGNIFICANCE

The current study reveals that these 12 trace elements in hair and fingernails are associated with GOC to varying degrees. Further studies and animal experiments are needed to clarify the associations and explore potential mechanisms.

IMPACT STATEMENT

The role of trace elements in the development or inhibition of gastroesophageal cancers (GOC) remains unclear. In this study, we further explored the associations between 12 trace elements and GOC based on a population-based case-control study conducted in Taixing, China. Higher levels of Ca, Zn, Fe, Al, Cr, Pb, Se, and V were positively associated with increased GOC, while inverse associations between higher levels of Mg, Mn, Sr, As, and GOC were observed. Observed associations were consistent in hair and fingernail samples. Moreover, interaction effects between hair level of Cr and smoking or alcohol drinking were identified.

Reduction in water consumption in premise plumbing systems: Impacts on lead concentration under different water qualities

Water conservation measures are increasing in response to regulatory requirements addressing the need for lower environmental footprint and in response to water shortages. In households with lead service lines (LSLs), lowering consumption can adversely impact lead release as it will increase stagnation. Using a lead dissolution model and data from extensive pilot studies on excavated LSLs, the impact of adaptation to different water conservation strategies on dissolved lead contamination at the kitchen tap is assessed under three water qualities and three LSL lengths (3, 14 and 30 m) using hydraulic and water quality modelling. Consumers' behavioural variability is also assessed based on integration of EPANET and results of the stochastic water demand model SIMDEUM. Demand reduction increased the dissolved lead concentrations (Pb_diss) at the end of the LSL with mean values ranging from 28.4 to 63.3 μg/L (without corrosion control) and from 4.6 to 9.9 μg/L with corrosion control (addition of orthophosphate and pH adjustment). Adding orthophosphate (1 mg P/L) to the water reduces the mean Pb_diss values at the kitchen tap from 7.1 μg/L to 1.2 μg/L for a high water demand scenario and from 31.2 to 4.9 μg/L for a low water demand scenario. Finally, the Integrated Exposure Uptake Biokinetic (IEUBK) model is used to predict the potential blood lead levels (BLLs) for children aged 0-84 months. Results showed that the orthophosphate addition of only 1 mg P/L can significantly decrease the proportion of children with a BLL >5 μg/dL, from 82 % to 17 %, under the most extreme water conservation scenario studied, using the 90th percentile of Pb_diss concentrations during usage at kitchen tap. Wide variations of Pb_diss concentrations at the kitchen tap were calculated at times of use over a week (up to 155 μg/L in lower demand scenarios, without corrosion control) showing evident limitations of single random daytime sampling.

A literature review of bench top and pilot lead corrosion assessment studies

Bench top and pilot lead corrosion studies are gaining more interest, considering revisions and upcoming improvements to the Lead and Copper Rule. This literature review identified studies ranging from simpler month(s)-long bench top dump-and-fill stagnant water tests (coupon tests/standing pipe tests) to more complicated year(s)-long intermittent flow pilot studies (recirculating pipe loops/once through pipe rigs). With increasing complexity in design and operation, studies more closely approximated real plumbing conditions (e.g., by incorporating harvested lead pipes and intermittent flow regimes) at increased cost, footprint, and duration. Comparison of bench top and pilot designs (in terms of lead test piece age/dimensions/configuration/replicates, study duration, sample collection, and other factors) can assist drinking water utilities, consultants, academics, and others to select a design that matches their needs and constraints. No matter the choice, surrogate systems cannot replace actual system water testing and are best complemented by other corrosion assessment tools.

Characterization of the aerosol produced from an aerated jet

Faucet aerators that form aerated water jets generate aerosols, which can constitute a risk of infection if the water is contaminated, particularly for vulnerable individuals near the sink. In this study, we characterize the size and trajectory of water droplets produced from an aerated jet. The detected particle diameter ranged from 3 to 150μm. The concentration of droplets in the air varied from near-zero to a maximum of 2×10¹¹particles/m³, depending on the location relative to the jet. We found four relevant categories of droplets based on their trajectories following their emission at the jet's free surface: particles with inertia high enough to escape the immediate vicinity of the jet (category 1), particles moving towards the jet (category 2), particles drawn into the aerator, which only included particles with a diameter smaller than 50μm (category 3), and particles with a near-vertical trajectory (category 4). Tracing category 1 particles to their generation location on the water interface shows a higher emission rate near the aerator. Finally, we employ a numerical model to compute the subsequent trajectories of droplets detected at the limits of the sampled domain. We find that particles whose diameter is smaller than 55μm completely dry and become airborne. Larger droplets deposit within a radius of 7cm around the jet, assuming a surface is located 20cm below the aerator tip. These results increase the fundamental understanding of the emission mechanisms of droplets in aerated jets and their fate in the sink environment.

Adsorption of Individual and Mixtures of β-Blockers and Copper in Soils and Sediments

The (bio)availability of pharmaceuticals at solid/water interfaces is governed by their sorption, which determines their concentrations in groundwaters and surface waters in contact with biota, and can be affected by the presence of other contaminants such as metallic trace elements likely to compete for adsorption sites and form complexes with pharmaceuticals. We studied the adsorption of the pharmaceuticals propranolol and sotalol-two β-blockers-on one soil and one sediment using batch experiments to assess their (bio)availability. The influence of contact time, pH, and concentration was studied. As in the real environment these contaminants are not alone but in mixtures, and they were studied alone, simultaneously added, and in the presence of Cu²⁺ , which is known to form coordination complexes with propranolol and sotalol, but their presence in mixtures did not alter their adsorption properties. Sotalol was more mobile in water and thus more bioavailable for organisms than propranolol. The mobility in surface waters of both β-blockers and thus their bioavailabity for organisms is more important than their risk of transfer to groundwater during rainwater infiltration and to surface water due to runoff. Environ Toxicol Chem 2022;41:2700-2707. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Seasonal Lead Release into Drinking Water and the Effect of Aluminum

Monitoring lead in drinking water is important for public health, but seasonality in lead concentrations can bias monitoring programs if it is not understood and accounted for. Here, we describe an apparent seasonal pattern in lead release into orthophosphate-treated drinking water, identified through point-of-use sampling at sites in Halifax, Canada, with various sources of lead. Using a generalized additive model, we extracted the seasonally varying components of time series representing a suite of water quality parameters and we identified aluminum as a correlate of lead. To investigate aluminum's role in lead release, we modeled the effect of variscite (AlPO₄·2H₂O) precipitation on lead solubility, and we evaluated the effects of aluminum, temperature, and orthophosphate concentration on lead release from new lead coupons. At environmentally relevant aluminum and orthophosphate concentrations, variscite precipitation increased predicted lead solubility by decreasing available orthophosphate. Increasing the aluminum concentration from 20 to 500 μg L^-1 increased lead release from coupons by 41% and modified the effect of orthophosphate, rendering it less effective. We attributed this to a decrease in the concentration of soluble (<0.45 μm) phosphorus with increasing aluminum and an accompanying increase in particulate lead and phosphorus (>0.45 μm).

Human Health Risk Assessment of Trace Elements in Tap Water and the Factors Influencing Its Value

(1) Background: The influence of tap water fittings construction and internal pipe-work on the release of heavy metals was investigated. (2) Methods: A statistical approach was applied for the examination of the chemistry of tap water in five different cities in southern Poland. In total, 500 samples were collected (from 100 to 101 samples in each city). The sampling protocol included information on the construction of the water supply network and the physicochemical parameters of measured tap water. (3) Results: The statistical analysis allowed to extract the crucial factors that affect the concentrations of trace elements in tap water. Age of connection, age of tap, age of pipe-work as well as material of connection, material of pipe-work and material of appliance reveal the most significant variability of concentrations observed for As, Al, Cd, Cu, Fe, Mn, Pb, and Zn. Calculated cancer risks (CRs) decrease with the following order of analysed elements Ni > Cd > Cr > As = Pb and can be associated with the factors that affect the appearance of such elements in tap water. The hazard index (HI) was evaluated as negligible in 59.1% of the sampling points and low in 40.1% for adults. For children, a high risk was observed in 0.2%, medium in 9.0%, negligible in 0.4%, and low for the rest of the analysed samples.

Rapid and simple lead service line detection screening protocol using water sampling

Many water systems are challenged with uncertainty regarding service line material type. This work investigated using a simple drinking water flushed sampling approach and a more complicated and invasive sequential profile sampling approach to predict whether homes had an existing lead service line (LSL). Homes that never had an LSL (control groups) and homes with LSLs (study groups) in two communities having different degrees of corrosion control were sampled. Using control groups' results, community-specific "threshold" lead levels were determined and compared to results from study groups. The flushed sampling maximum lead concentration (FMC) of lead accurately predicted 100% and 60% of LSL sites for the community with poor and good corrosion control, respectively. The weighted average sequential profile lead concentration (WASLC) increased the 40% not identified as LSL sites by fully flushed samples to 100%. The WASLC closely followed by the maximum sequential profile lead concentration were most reliable in identifying LSLs.

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.

Variability and sampling of lead (Pb) in drinking water: Assessing potential human exposure depends on the sampling protocol

Lead (Pb) in drinking water has re-emerged as a modern public health threat which can vary widely in space and in time (i.e., between homes, within homes and even at the same tap over time). Spatial and temporal water Pb variability in buildings is the combined result of water chemistry, hydraulics, Pb plumbing materials and water use patterns. This makes it challenging to obtain meaningful water Pb data with which to estimate potential exposure to residents. The objectives of this review paper are to describe the root causes of intrinsic Pb variability in drinking water, which in turn impacts the numerous existing water sampling protocols for Pb. Such knowledge can assist the public health community, the drinking water industry, and other interested groups to interpret/compare existing drinking water Pb data, develop appropriate sampling protocols to answer specific questions relating to Pb in water, and understand potential exposure to Pb-contaminated water. Overall, review of the literature indicated that drinking water sampling for Pb assessment can serve many purposes. Regulatory compliance sampling protocols are useful in assessing community-wide compliance with a water Pb regulatory standard by typically employing practical single samples. More complex multi-sample protocols are useful for comprehensive Pb plumbing source determination (e.g., Pb service line, Pb brass faucet, Pb solder joint) or Pb form identification (i.e., particulate Pb release) in buildings. Exposure assessment sampling can employ cumulative water samples that directly capture an approximate average water Pb concentration over a prolonged period of normal household water use. Exposure assessment may conceivably also employ frequent random single samples, but this approach warrants further investigation. Each protocol has a specific use answering one or more questions relevant to Pb in water. In order to establish statistical correlations to blood Pb measurements or to predict blood Pb levels from existing datasets, the suitability of available drinking water Pb datasets in representing water Pb exposure needs to be understood and the uncertainties need to be characterized.

Thermo-mechanical processing of brass components for potable-water usage increases risks of Pb leaching

The problem of lead contamination in potable water has been a serious concern in different countries. Although the use of leaded welding solder has been banned and brass components used in potable water pipework have to be of the nominally "lead-free" grade in most jurisdictions, incidents of excessive lead leaching are still reported. The widely advocated explanation of lead leaching from brass components in terms of corrosion and the formation of electrochemical cells is inadequate since mechanical cutting is also known to cause lead segregation on brass surfaces. In this study, the effects of lead segregation on brass surfaces and subsequent leaching to contacting water resulting from thermo-mechanical processing of the brass are studied. The results indicate that mechanical milling and polishing that replicate the common processing involved in pipeline installation yield a significant increase in surface lead, and a strong correlation exists between lead leaching and the plastic deformation of the brass surface. Furthermore, flame-torch treatment that replicates the common brazing of brass also results in a significant increase in surface lead. These results indicate that the common thermo-mechanical processing of brass piping components poses a real risk of lead contamination in potable water, and revision in the common protocols for handling lead components may be necessary.

Effect of Aluminum on Lead Release to Drinking Water from Scales of Corrosion Products

The occurrence of aluminum in scales on lead pipes is common. This study aimed to identify factors that influence Al accumulation on oxidized lead surfaces and to determine whether the presence of Al impacts Pb release from corrosion products to water. Al accumulation and Pb release were monitored both with and without the addition of phosphate as a corrosion inhibitor. Pb coupons with corrosion scales were exposed to chlorinated water for up to 198 days to investigate Al accumulation and Pb release. Al accumulation was facilitated by Pb corrosion products, but its accumulation was inhibited by phosphate addition. During the study period, the formation of Al deposits did not affect Pb release when phosphate was absent. In an Al-free system, the addition of 1.0 mg/L phosphate (as P) lowered the dissolved Pb concentration below 1.0 μg/L. In a system containing 200 μg/L Al, the emergence of phosphate's effect on Pb control was delayed, and the dissolved Pb concentration decreased but stabilized at a higher value (10-12 μg/L) than in the Al-free system. Phosphohedyphane (Ca₂Pb₃(PO₄)₃Cl) was formed in all phosphate-containing systems, and PbO₂ was formed independent of phosphate addition. The effect of Al on Pb release was probably related to its influence on the composition and morphology of Pb-containing minerals on coupon surfaces. The laboratory study has unavoidable limitations in its ability to simulate all conditions in real lead service lines, but this study still highlights the importance of considering the influence of Al when designing Pb corrosion control strategies.

Protection through participation: Crowdsourced tap water quality monitoring for enhanced public health

Lead contamination in municipal drinking water is a national public health issue and is generally the result of water contact with leaded distribution piping and on premise plumbing. As a result, the US Environmental Protection Agency's Lead and Copper Rule requires point of use sampling methods at a small fraction of consumer taps on the public water distribution system. While this approach is practical, it leaves large gaps of consumers without direct monitoring and protection. In response, a novel contest-based crowdsourcing study was conducted to engage the public in monitoring their own water quality at their home taps and study factors that shaped participation in drinking water monitoring. Participants were asked to collect samples of their household drinking water through social media postings, kiosks, and community events with the chance to win a cash prize. The project distributed approximately 800 sampling packets and received 147 packets from participants of which 93% had at least partially completed surveys. On average, private wells were found to have higher lead levels than the public water supply, and the higher lead levels were not attributed to older building age. There is also no statistical relevance between the participants' perceived and actual tap water quality. Survey responses indicated that citizens were motivated to participate in the project due to concerns about their own health and/or the health of their families. In contrast, participants reported that they were not motivated by the cash prize. This project helps inform future public engagement with water quality monitoring, create new knowledge about the influence of personal motivations for participation, and provide recommendations to help increase awareness of water quality issues.