Tracking reduction of water lead levels in two homes during the Flint Federal Emergency

Quantitative Microbial Risk Assessment Framework Incorporating Water Ages with Legionella pneumophila Growth Rates

Water age in drinking water systems is often used as a proxy for water quality but is rarely used as a direct input in assessing microbial risk. This study directly linked water ages in a premise plumbing system to concentrations of Legionella pneumophila via a growth model. In turn, the L. pneumophila concentrations were used for a quantitative microbial risk assessment to calculate the associated probabilities of infection (Pinf) and clinically severe illness (Pcsi) due to showering. Risk reductions achieved by purging devices, which reduce water age, were also quantified. The median annual Pinf exceeded the commonly used 1 in 10,000 (10-4) risk benchmark in all scenarios, but the median annual Pcsi was always 1-3 orders of magnitude below 10-4. The median annual Pcsi was lower in homes with two occupants (4.7 × 10-7) than with one occupant (7.5 × 10-7) due to more frequent use of water fixtures, which reduced water ages. The median annual Pcsi for homes with one occupant was reduced by 39-43% with scheduled purging 1-2 times per day. Smart purging devices, which purge only after a certain period of nonuse, maintained these lower annual Pcsi values while reducing additional water consumption by 45-62%.

Lead levels in drinking water from point-of-use dispensers: a case study of elementary schools in Taichung, Taiwan

Drinking water contaminated with lead has adverse health consequences, particularly in young children. Water dispensed from point-of-use dispensers is generally regarded as drinking water instead of conventional tap water in Taiwan, and such dispensers are installed in all public facilities, including elementary schools. However, studies on drinking water quality are mainly focused on tap water, while dispenser water quality is less known. Hence, this study investigated lead concentrations in drinking water from point-of-use dispensers in elementary schools of Taichung, Taiwan. Water samples were collected between September 2019 and February 2021 from 86 schools across 24 districts utilizing a modified first draw sampling protocol to collect ten 100-mL sequential samples. Approximately 26% of the schools had at least one sample exceeding 10 μg/L (Taiwan EPA standard), with the highest level reaching 99.2 μg/L. Exceedance tendency varied with water use, seasons, and age of the schools. Samples collected over the weekends and during summer showed higher levels and frequencies of contamination. Lead levels surpassing the standard were observed in 14% of weekend and 17% of summer samples, compared to only 4% of weekday and 4% of winter samples. Similarly, while older schools (age > 40 years) exhibited higher contamination, young schools (age < 20 years) were also not entirely safe. This study reveals that point-of-use dispensers do not always provide safe drinking water. Findings also indicate the susceptibility of children in elementary schools to lead exposure through their drinking water. Therefore, a routine monitoring program for heavy metals, including lead, in drinking water is urgently needed.

Addressing systemic problems with exposure assessments to protect the public's health

BACKGROUND

Understanding, characterizing, and quantifying human exposures to environmental chemicals is critical to protect public health. Exposure assessments are key to determining risks to the general population and for specific subpopulations given that exposures differ between groups. Exposure data are also important for understanding where interventions, including public policies, should be targeted and the extent to which interventions have been successful. In this review, we aim to show how inadequacies in exposure assessments conducted by polluting industries or regulatory agencies have led to downplaying or disregarding exposure concerns raised by communities; that underestimates of exposure can lead regulatory agencies to conclude that unacceptable risks are, instead, acceptable, allowing pollutants to go unregulated; and that researchers, risk assessors, and policy makers need to better understand the issues that have affected exposure assessments and how appropriate use of exposure data can contribute to health-protective decisions.

METHODS

We describe current approaches used by regulatory agencies to estimate human exposures to environmental chemicals, including approaches to address limitations in exposure data. We then illustrate how some exposure assessments have been used to reach flawed conclusions about environmental chemicals and make recommendations for improvements.

RESULTS

Exposure data are important for communities, public health advocates, scientists, policy makers, and other groups to understand the extent of environmental exposures in diverse populations. We identify four areas where exposure assessments need to be improved due to systemic sources of error or uncertainty in exposure assessments and illustrate these areas with examples. These include: (1) an inability of regulatory agencies to keep pace with the increasing number of chemicals registered for use or assess their exposures, as well as complications added by use of 'confidential business information' which reduce available exposure data; (2) the failure to keep assessments up-to-date; (3) how inadequate assumptions about human behaviors and co-exposures contribute to underestimates of exposure; and (4) that insufficient models of toxicokinetics similarly affect exposure estimates.

CONCLUSION

We identified key issues that impact capacity to conduct scientifically robust exposure assessments. These issues must be addressed with scientific or policy approaches to improve estimates of exposure and protect public health.

Meeting the Water and Sanitation Challenges of Underbounded Communities in the U.S

Water and sanitation (wastewater) infrastructure in the United States is aging and deteriorating, with massive underinvestment over the past several decades. For many years, lack of attention to water and sanitation infrastructure has combined with racial segregation and discrimination to produce uneven access to water and wastewater services resulting in growing threats to human and environmental health. In many metropolitan areas in the U.S., those that often suffer disproportionately are residents of low-income, minority communities located in urban disadvantaged unincorporated areas on the margins of major cities. Through the process of underbounding (the selective expansion of city boundaries to exclude certain neighborhoods often based on racial demographics or economics), residents of these communities are disallowed municipal citizenship and live without piped water, sewage lines, and adequate drainage or flood control. This Perspective identifies the range of water and sanitation challenges faced by residents in these communities. We argue that future investment in water and sanitation should prioritize these communities and that interventions need to be culturally context sensitive. As such, approaches to address these problems must not only be technical but also social and give attention to the unique geographic and political setting of local infrastructures.

A critical opportunity: Detecting and Reducing Lead in Drinking Water at child care facilities

There is no safe level of lead exposure. As exposure from point sources like lead paint have decreased, non-point sources such as drinking water have become a greater proportional source of total lead exposure. Even at low levels, lead exposure is shown to harm children, contributing to impaired development as well as learning and behavioral issues. This paper summarizes the key results of an Environmental Defense Fund (EDF) pilot study conducted at 11 child care facilities in 4 US states to evaluate approaches to testing and remediating lead in water at child care facilities. Over 75% of first draw samples contained lead levels under the 1 μg/L level recommended by the American Academy of Pediatrics (AAP). However, 10 of 11 child care facilities produced at least one sample above 1 μg/L. Fixture flushing, aerator cleaning, and fixture replacement were evaluated as remediation strategies. Fixture replacement was effective when initial lead was above 5 μg/L. Aerator cleaning did not have a measurable effect on lead levels for most fixtures but unexpectedly significantly increased lead levels in approximately 30% of fixtures. The 2021 Lead and Copper Rule (LCR) revision was applied to study data to determine whether updates would flag cases of low-level lead in child care settings and was found insufficient to prompt mitigation unless high lead was present at most taps.

Are there excess fetal deaths attributable to waterborne lead exposure during the Flint Water Crisis? Evidence from bio-kinetic model predictions and Vital Records

BACKGROUND

Flint, Michigan had elevated water lead (Pb) levels during the 2014-15 Flint Water Crisis (FWC) and reports claim the exposures caused excess fetal deaths.

OBJECTIVE

To model the likelihood of excess fetal deaths occurring from FWC lead exposure and compare results to Vital Records.

METHODS

We used an established bio-kinetic model to predict relative blood lead trends in pregnant women from characteristic exposure to 90th percentile water lead levels (WLLs), and another established model to then estimate characteristic miscarriage (<20 gestation weeks) odds ratios (OR) in Flint (2011-17). For comparison, we made similar predictions for exposures during (1) Washington DC's worst water lead crisis year (2001), (2) Flint "Resident Zero" home with anomalously high WLLs, and (3) 19th century lead-based abortifacients. Data on stillbirths (≥20 gestation weeks) and total fertility rates were obtained from the State of Michigan.

RESULTS

The models predicted that pregnant women drinking water with representative 90th percentile WLLs had a miscarriage OR during the worst FWC period (June-August 2014) of 1.21 (95% CI = 1.02,1.60), versus 1.66 (95% CI = 1.07, 3.56) during a time of high water lead 3 years before the FWC and 1.00 (95% CI = 1.00, 1.01) post-FWC. The corresponding predicted OR in late-2001 for Washington D.C. when higher fetal death rates were statistically associated with very high WLLs was 3.01 (95% CI = 1.16, 16.23). No apparent differences were revealed in overall and race-specific stillbirth rates before, during, or after the FWC. Total fertility rates dropped 6.8% during the FWC (April 2014-October 2015 versus April 2012-October 2013), but this is now revealed to be within the normal annual variation (-9.4% to +15%) observed post-FWC when residents were protected from water lead exposure.

SIGNIFICANCE

Neither model simulations nor Vital Records data are consistent with the hypothesis that there was an uptick in fetal deaths or decreased fertility attributable to water lead exposure during the FWC.