Portable FRET-Based Biosensor Device for On-Site Lead Detection.

Most methods for measuring environmental lead (Pb) content are time consuming, expensive, hazardous, and restricted to specific analytical systems. To provide a facile, safe tool to detect Pb, we created pMet-lead, a portable fluorescence resonance energy transfer (FRET)-based Pb-biosensor. The pMet-lead device comprises a 3D-printed frame housing a 405-nm laser diode-an excitation source for fluorescence emission images (YFP and CFP)-accompanied by optical filters, a customized sample holder with a Met-lead 1.44 M1 (the most recent version)-embedded biochip, and an optical lens aligned for smartphone compatibility. Measuring the emission ratios (Y/C) of the FRET components enabled Pb detection with a dynamic range of nearly 2 (1.96), a pMet-lead/Pb dissociation constant (Kd) 45.62 nM, and a limit of detection 24 nM (0.474 µg/dL, 4.74 ppb). To mitigate earlier problems with a lack of selectivity for Pb vs. zinc, we preincubated samples with tricine, a low-affinity zinc chelator. We validated the pMet-lead measurements of the characterized laboratory samples and unknown samples from six regions in Taiwan by inductively coupled plasma mass spectrometry (ICP-MS). Notably, two unknown samples had Y/C ratios significantly higher than that of the control (3.48 ± 0.08 and 3.74 ± 0.12 vs. 2.79 ± 0.02), along with Pb concentrations (10.6 ppb and 15.24 ppb) above the WHO-permitted level of 10 ppb in tap water, while the remaining four unknowns showed no detectable Pb upon ICP-MS. These results demonstrate that pMet-lead provides a rapid, sensitive means for on-site Pb detection in water from the environment and in living/drinking supply systems to prevent potential Pb poisoning.

Water lead exposure risk in Flint, Michigan after switchback in water source: Implications for lead service line replacement policy.

In February of 2016, the City of Flint, Michigan commenced the FAST start initiative with the aim "to get the lead out of Flint" by replacing lead and galvanized steel service lines throughout the city. An estimated 29,100 parcels are scheduled for service line replacement (SLR) at an expected cost of $172 million. The lead exposure benefits of SLR are evaluated by analyzing Sentinel data on hundreds of repeatedly sampled homes in Flint from February 16, 2016 to July 21, 2017, comparing water lead (WL) in homes with and without lead service lines. Samples taken from homes with lead service lines were significantly more likely to exceed specified thresholds of WL than homes without lead service lines. Second, regardless of service line material type, sampled homes experienced significant reductions in WL with elapsed time from Flint's switchback to water provided by the Detroit Water and Sewage Department. Third, the risk of exceedance of WL > 15 µg/L was uncorrelated with service line material type. These results are robust to sample restrictions, period stratification, time operations, reference group definitions, and statistical modeling procedures. On the question of what is gained from SLR over optimal corrosion control techniques, we simulated age-specific lead uptake (µg/day) and blood lead levels (µg/dL) for children in Flint at 16 and 90 weeks of elapsed time from Flint's switchback to Detroit water. At 90 weeks from the switchback in water source, the quantity of water lead consumed by children in homes with lead service lines decreased 93%, as compared to 16 weeks. Lead exposure benefits of SLR have declined in time, with modest differences in lead uptake across homes with different service lines. In light of results, policy considerations for Flint and nationwide are discussed.

Cost-benefit of point-of-use devices for lead reduction.

BACKGROUND: Lead exposure represents a significant human health concern that often occurs with little warning to the consumer. Water lead levels can be mitigated by point-of-use (POU) devices such as reverse osmosis, distillation, or activated carbon with lead reduction media. OBJECTIVES: This study assessed a partial cost-benefit of residential installation of POU devices to reduce lead concentrations in drinking water and examined the economic impact at the community level based on exposures reported in Flint, Michigan. METHODS: We calculated the individual consumer breakeven point for each lead abatement option by subtracting the lifetime cost of device installation and maintenance from the lifetime cost of lead exposure through its impact on intelligence (IQ) and lifetime earnings. This approach was then extrapolated to the community level based on reported lead exposures in Flint, Michigan. RESULTS: Based on operating POU device costs, lead absorption from water, and economic losses associated with reduced IQ, initial water lead levels associated with consumer breakeven points for reverse osmosis (7.31 µg/L), activated carbon (3.73 µg/L), and distillation (12.0 µg/L) were calculated. For example, an individual consuming water with 25 µg/L of lead, similar to the 90th percentile of concentrations measured in Flint, Michigan, would have an expected blood lead level of 1.25 µg/dL, a corresponding loss of 0.641 IQ points, and a lifetime economic earnings loss of $14,284. Over 70 years of continued use, activated carbon with lead reduction media is the least expensive device to maintain and operate as compared to reverse osmosis and distillation. CONCLUSIONS: Infrastructure failures related to drinking water are unpredictable and exposure to contaminates can have significant economic ramifications. POU devices represent a cost-effective option to reduce the impact of lead exposure, particularly when water lead concentrations exceed regulated levels.

Drinking water lead and socioeconomic factors as predictors of blood lead levels in New Jersey's children between two time periods.

As blood lead levels have decreased over time, the relative contributions of alternative lead sources warrant further examination. Much attention has been paid to the relative contribution of lead in drinking water, particularly after the discovery of contaminated drinking water in Flint, Michigan which has also renewed interest in the persistent socioeconomic and racial disparities in children's exposure to lead. As the environmental sources of lead exposure are shifting in importance over time, we decided to examine how demographic, socioeconomic, and environmental factors may confound or interact with each other, and whether these relationships have changed over time. The study population included all New Jersey resident children aged 6-26 months with at least one blood lead specimen collected between 2000 and 2004 (n = 288,758) or 2010 and 2014 (n = 326,530). Reported 90th percentile water lead data (in parts per billion) was summarized annually for each water system statewide. Children's blood lead levels have decreased over time from a statewide geometric mean of 2.47 µg/dL (95% CI 2.46, 2.48) between 2000 and 2004 to 1.57 µg/dL (95% CI 1.57, 1.57) between 2010 and 2014. Individual-level factors of child's age and season of blood draw and area-based measures of race, older housing, and poverty were predictors of children's blood lead levels. Conclusions regarding area-based measure of Hispanic ethnicity are limited and require further research. The narrow range and low levels of area-based lead concentrations in drinking water limits the ability to detect associations with blood lead levels. Racial disparities in blood lead continue to persist but economic disparities may be narrowing as blood lead concentrations continue to decline.

A novel public health threat - high lead solder in stainless steel rainwater tanks in Tasmania.

OBJECTIVE: We identified two water tanks in Tasmania with water lead concentrations exceeding the Australian Drinking Water Guidelines (ADWG) limit; they had been constructed with stainless steel and high-lead solder from a single manufacturer. An investigation was initiated to identify all tanks constructed by this manufacturer and prevent further exposure to contaminated water. METHODS: To identify water tanks we used sales accounts, blood and water lead results from laboratories, and media. We analysed blood and water lead concentration results from laboratories and conducted a nested cohort study of blood lead concentrations in children aged <18 years. RESULTS: We identifed 144 tanks constructed from stainless steel and high lead solder. Median water lead concentrations were significantly higher in the stainless steel tanks (121µg/L) than in the galvanised tanks (1µg/L). Blood lead concentrations ranged from 1 to 26µg/dL (median 5µg/dL); of these, 77% (n=50) were below the then-recommended health-related concentration of 10µg/dL. Concentrations in the 15 people (23%) above this limit ranged from 10-26µg/dL, with a median of 14µg/dL. The median blood lead concentration in the nested cohort of children was initially 8.5µg/dL, dropping to 4.5µg/dL after follow-up. CONCLUSIONS: Lead concentrations in the water tanks constructed from stainless steel and high-lead solder were up to 200 times above the recommended ADWG limits. Implications for public health: This investigation highlights the public health risk posed by use of non-compliant materials in constructing water tanks.

Editorial: Lead Risk Assessment and Health Effects.

In 1980, Clair C. Patterson stated: "Sometime in the near future it probably will be shown that the older urban areas of the United States have been rendered more or less uninhabitable by the millions of tons of poisonous industrial lead residues that have accumulated in cities during the past century". We live in the near future about which this quote expressed concern. This special volume of 19 papers explores the status of scientific evidence regarding Dr. Patterson's statement on the habitability of the environments of communities. Authors from 10 countries describe a variety of lead issues in the context of large and small communities, smelter sites, lead industries, lead-based painted houses, and vehicle fuel treated with lead additives dispersed by traffic. These articles represent the microcosm of the larger health issues associated with lead. The challenges of lead risk require a concerted global action for primary prevention.