A national survey of lead and other metal(loids) in residential drinking water in the United States.

Background: Exposure to lead (Pb), arsenic (As) and copper (Cu) may cause significant health issues including harmful neurological effects, cancer or organ damage. Determination of human exposure-relevant concentrations of these metal(loids) in drinking water, therefore, is critical.

Objective: We sought to characterize exposure-relevant Pb, As, and Cu concentrations in drinking water collected from homes participating in the American Healthy Homes Survey II, a national survey that monitors the prevalence of Pb and related hazards in United States homes.

A holistic approach to lead pipe scale analysis: Importance, methodology, and limitations.

With lead service lines (LSLs) remaining for decades to come, scale analyses are critical to helping limit lead exposure from drinking water. This laboratory has used an integrated suite of analytical techniques to characterize the elemental composition, mineral identification, and physical features of scales, helping the water industry to evaluate, predict, and reduce lead corrosion. The methods used in this laboratory to prepare and analyze the LSL scale, and guidance to achieving reliable and meaningful results, are described.

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.

Theoretical equilibrium lead(II) solubility revisited: Open source code and practical relationships.

A theoretical equilibrium lead(II) (Pb(II)) solubility model coded in Fortran (LEADSOL) was updated and implemented in open source R code, verified against LEADSOL output, and used to simulate theoretical equilibrium total soluble Pb(II) (TOTSOLPb) concentrations under a variety of practical scenarios. The developed R code file (app.R) is publicly available for download at GitHub (https://github.

Framework for Modeling Lead in Premise Plumbing Systems Using EPANET.

The lead contamination of drinking water in homes and buildings remains an important public health concern. In order to assess strategies to measure and reduce exposure to lead from drinking water, models are needed that incorporate the multiple factors affecting lead concentrations in premise plumbing systems (PPS). In this study, the use of EPANET, a commonly used hydraulic and water quality model for water distribution systems, was assessed for its ability to predict lead concentrations in PPS.

Orthophosphate Interactions with Destabilized PbO Scales.

This research presents two case studies in which a change in the disinfectant from free chlorine to chloramine caused an increase in lead corrosion. In both systems, the predominantly tetravalent lead (PbO) scales destabilized as a result of disinfectant change. Orthophosphate corrosion control was used in both systems, and the effect of this treatment chemical on the destabilized PbO scales was examined.

Lead Particle Size Fractionation and Identification in Newark, New Jersey's Drinking Water.

Following a pH reduction in their drinking water over a span of more than 20 years, the City of Newark, New Jersey, has struggled with elevated lead (Pb) release from Pb service lines and domestic plumbing in the zone fed by the Pequannock Water Treatment Plant. In response, Newark initiated orthophosphate addition and provided faucet-mounted point-of-use (POU) filters and pitcher filters certified for Pb and particulate reduction under NSF/ANSI Standards 53 and 42 to residential homes in that zone. Water chemistry analysis and size fractionation sampling were performed at four of these houses.

Georgeite: A Rare Copper Mineral with Important Drinking Water Implications.

Significant research has been conducted on copper corrosion and solubility in drinking water, including the establishment of the "cupric hydroxide model". The model describes the temporal aging and associated solubility changes of copper minerals beginning with the most soluble solid, cupric hydroxide. Although the model explains copper levels in field observations well, there are aspects of the model that are not well understood, including a lack of evidence of the presence of cupric hydroxide in drinking water distribution systems.

POU water filters effectively reduce lead in drinking water: a demonstration field study in flint, Michigan.

A field study was conducted to test the effectiveness of faucet-mounted point of use (POU) water filters for removing high concentrations of lead in drinking water from premise plumbing sources and lead service lines (LSL). These filters were concurrently certified for total lead removal under NSF/ANSI Standard 53 (NSF/ANSI-53) and for fine particulate (Class I) reduction under NSF/ANSI Standard 42 (NSF/ANSI-42). In 2016, filtered and unfiltered drinking water samples were collected at over 345 locations in Flint, Michigan.

Sequential drinking water sampling as a tool for evaluating lead in flint, Michigan.

Eliminating the sources of human lead exposure is an ongoing public health goal. Identifying the make-up of household plumbing and service line material type is important for many reasons including understanding lead release sources and mechanisms, targeting locations for lead service line (LSL) removal, and assessing the effectiveness of lead remediation strategies. As part of the response to Flint, Michigan's drinking water lead public health crisis, a return to their original drinking water source (Lake Huron) and an increase in orthophosphate dose was implemented in late 2015.

Water quality-pipe deposit relationships in Midwestern lead pipes.

The conventional wisdom of lead-scale solubility has been built over the years by geochemical solubility models, experimental studies, and field sampling utilizing multiple protocols. Rarely, have the mineral phases from scales formed in real-world drinking water lead service lines (LSLs) been compared to theoretical predictions. In this study, model predictions are compared to LSL scales from 22 drinking water distribution systems.

Design and Testing of USEPA'S Flint Pipe Rig for Corrosion Control Evaluation.

The US Environmental Protection Agency's Office of Research and Development designed, fabricated, and installed four pipe rigs in Flint, Mich., to help the city optimize corrosion control. The lead service line (LSL) pipe loops were constructed of polyvinyl chloride pipe and fittings and welded steel channel frames.

A Model for Estimating the Impact of Orthophosphate on Copper in Water.

The nature of copper phosphate minerals in drinking water distribution systems has remained largely unsolved despite being an important link to reducing cuprosolvency. Chemical equilibrium modeling has also largely failed to accurately predict soluble copper in the presence of orthophosphate. The objective of this work was to develop and validate an empirical copper solubility model that considered pH, dissolved inorganic carbon (DIC), and orthophosphate from a series of bench-scale copper precipitation experiments.

Mineralogical Evidence of Galvanic Corrosion in Drinking Water Lead Pipe Joints.

Galvanic corrosion as a mechanism of toxic lead release into drinking water has been under scientific debate in the U.S. for over 30 years.

Scale Formation Under Blended Phosphate Treatment for a Utility With Lead Pipes.

US corrosion control practice often assumes that the orthophosphate component of blended phosphate corrosion inhibitors causes the formation of low-solubility lead-orthophosphate solids that control lead release into drinking water. This study identified the solids that formed on the interior surface of a lead service line and a galvanized steel pipe excavated from a system using a proprietary blended phosphate chemical. The scale was analyzed by X-ray diffraction, X-ray fluorescence, and scanning electron microscopy/energy dispersive spectroscopy.

Low contribution of PbO2-coated lead service lines to water lead contamination at the tap.

To determine if residential water sampling corroborates the expectation that formation of stable PbO2 coatings on lead service lines (LSLs) provides an effective lead release control strategy, lead profile sampling was evaluated for eight home kitchen taps in three U.S. cities with observed PbO2-coated LSLs (Newport, Rhode Island; Cincinnati and Oakwood, Ohio).

Detection and evaluation of elevated lead release from service lines: a field study.

Comparative stagnation sampling conducted in 32 homes in Chicago, Illinois with lead service lines demonstrated that the existing regulatory sampling protocol under the U.S. Lead and Copper Rule systematically misses the high lead levels and potential human exposure.

The inhibition of Pb(IV) oxide formation in chlorinated water by orthophosphate.

Historically, understanding lead solubility and its control in drinking water has been based on Pb(II) chemistry. Unfortunately, there is very little information available regarding the nature of Pb(IV) oxides in finished drinking water and water distribution systems, and the conditions under which they persist. The objective of this research was to explore the impact of orthophosphate on the realistic pathways that lead to the formation of Pb(IV) oxides in chlorinated water.

Identification and distribution of vanadinite (Pb5(V5+O4)3Cl) in lead pipe corrosion by-products.

This study presents the first detailed look at vanadium (V) speciation in drinking water pipe corrosion scales. A pool of 34 scale layers from 15 lead or lead-lined pipes representing eight different municipal drinking water distribution systems in the Northeastern and Midwestern portions of the United States were examined. Diverse synchrotron-based techniques, including bulk XANES (X-ray absorption near edge spectroscopy), micro-XANES, micro-XRD (X-ray diffraction), and micro-XRF (X-ray fluorescence) mapping were employed along with traditional powder XRD, SEM-EDXA (scanning electron microscopy-energy dispersive X-ray analysis), and ICP-OES (inductively coupled plasma-optical emission spectrometry) to evaluate vanadium speciation and distribution in these deposits.

Lead exposures in U.S. Children, 2008: implications for prevention.

Objective: We reviewed the sources of lead in the environments of U.S. children, contributions to children's blood lead levels, source elimination and control efforts, and existing federal authorities.

Occurrence of contaminant accumulation in lead pipe scales from domestic drinking-water distribution systems.

Previously, contaminants, such as AI, As, and Ra, have been shown to accumulate in drinking-water distribution system solids. Accumulated contaminants could be periodically released back into the water supply causing elevated levels at consumers taps, going undetected by most current regulatory monitoring practices and consequently constituting a hidden risk. The objective of this study was to determine the occurrence of over 40 major scale constituents, regulated metals, and other potential metallic inorganic contaminants in drinking-water distribution system Pb (lead) or Pb-lined service lines.