Flint, Michigan switched to the Flint River as a temporary drinking water source without implementing corrosion control in April 2014. Ten months later, water samples collected from a Flint residence revealed progressively rising water lead levels (104, 397, and 707 μg/L) coinciding with increasing water discoloration. An intensive follow-up monitoring event at this home investigated patterns of lead release by flow rate-all water samples contained lead above 15 μg/L and several exceeded hazardous waste levels (>5000 μg/L). Forensic evaluation of exhumed service line pipes compared to water contamination "fingerprint" analysis of trace elements, revealed that the immediate cause of the high water lead levels was the destabilization of lead-bearing corrosion rust layers that accumulated over decades on a galvanized iron pipe downstream of a lead pipe. After analysis of blood lead data revealed spiking lead in blood of Flint children in September 2015, a state of emergency was declared and public health interventions (distribution of filters and bottled water) likely averted an even worse exposure event due to rising water lead levels.

In April 2014, the drinking water source in Flint, Michigan was switched from Lake Huron water with phosphate inhibitors to Flint River water without corrosion inhibitors. The absence of corrosion control and use of a more corrosive source increased lead leaching from plumbing. Our city-wide citizen science water lead results contradicted official claims that there was no problem- our 90th percentile was 26.8 μg/L, which was almost double the Lead and Copper Rule action level of 15 μg/L. Back calculations of a LCR sampling pool with 50% lead pipes indicated an estimated 90th percentile lead value of 31.7 μg/L (±4.3 μg/L). Four subsequent sampling efforts were conducted to track reductions in water lead after the switch back to Lake Huron water and enhanced corrosion control. The incidence of water lead varied by service line material. Between August 2015 and November 2016, median water lead reduced from 3.0 to <1 μg/L for homes with copper service lines, 7.2-1.9 μg/L with galvanized service lines, and 9.9-2.3 μg/L with lead service lines. As of summer 2017, our 90th percentile of 7.9 μg/L no longer differed from official results, which indicated Flint's water lead levels were below the action level.

Increased road salt use and resulting source water contamination has widespread implications for corrosion of drinking water infrastructure, including chloride acceleration of galvanic corrosion and other premature plumbing failures. In this study, we utilized citizen science sampling, bench-scale corrosion studies, and state-level spatial modeling to examine the potential extent of chloride concentrations in groundwater and the resulting impact on private wells in New York. Across the sampled community, chloride levels varied spatially, with the highest levels in private wells downgradient of a road salt storage facility followed by wells within 30 m of a major roadway. Most well users surveyed (70%) had stopped drinking their well water for aesthetic and safety reasons. In the bench-scale experiment, increasing chloride concentration in water increased galvanic corrosion and dezincification of plumbing materials, resulting in increased metal leaching and pipe wall thinning. Our simple spatial analysis suggests that 2% of private well users in New York could potentially be impacted by road salt storage facilities and 24% could potentially be impacted by road salt application. Our research underscores the need to include the damage to public and privately owned drinking water infrastructure in future discussion of road salt management.

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The pervasiveness of lead in drinking water poses a significant public health threat, which can be reduced by implementing preventive measures. However, the causes of elevated lead in water and the benefits of lead in water avoidance strategies are often misunderstood. Based on experiences in the United States, this paper describes an oversimplified 'lead in water equation' to explain key variables controlling the presence of lead in drinking water to better inform public health practitioners, government officials, utility personnel, and concerned residents. We illustrate the application of the equation in Flint, Michigan and explore the primary household-level water lead avoidance strategies recommended during the crisis, including flushing, filtration, bottled water use, and lead pipe removal. In addition to lead reduction, strategies are evaluated based on costs and limitations. While these lead avoidance strategies will reduce water lead to some degree, the costs, limitations, and effectiveness of these strategies will be site-and event-specific. This paper presents a simplified approach to communicate key factors which must be considered to effectively reduce waterborne lead exposures for a wide range of decision makers.These authors contributed equally to the work.This article has been made Open Access thanks to the generous support of a global network of libraries as part of the Knowledge Unlatched Select initiative.

Water leaks in distribution system mains and premise plumbing systems have very high costs and public health implications. The possible in situ remediation of leaks while a pipeline is in service could reduce leaking at costs orders of magnitude lower than conventional pipe repair, rehabilitation, or replacement. Experiences of Roman engineers and recent field observations suggest that such processes can occur naturally or may even be engineered to ameliorate leaks, including those caused by metallic corrosion. Three mechanisms of in situ leak remediation (i.e., metallic corrosion, physical clogging, and precipitation) are described in this paper, in an effort to understand the role of physical factors (e.g., temperature, pressure, and leak size) and water chemistry (e.g., pH, alkalinity, corrosion inhibitors, dissolved oxygen, and turbidity) in controlling in situ remediation for both inert (plastic and aged concrete) and chemically reactive (new concrete, copper, and iron) pipe materials. Although there are possible limitations and uncertainties with the phenomenon, including the fraction of pipeline leaks to which it might apply and the durability/longevity of remediation, such approaches may prove useful in economically sustaining some aging drinking water infrastructure assets and reducing future failure rates.

Iron corrosion in drinking water distribution systems causes water discoloration, water quality deterioration, hydraulic loss, and even pipe failures, which are usually influenced by pipe scale structure, water hydraulics, water chemistry, and other factors. This work evaluated the effects of chloride, sulfate, and dissolved inorganic carbon (DIC) on iron release from a 90-year-old cast iron pipe section at water pH 8.0 under stagnant conditions. Experimental results showed that the addition of 150 mg/L sulfate to water significantly increased the mean total iron concentrations to 1.13-2.68 mg/L, relative to 0.54-0.79 mg/L for the baseline water with only 10 mg C/L DIC. Similar results were observed under conditions when chloride was added, and when sulfate and chloride were added together. In contrast, the mean total iron concentrations were significantly reduced by 53-80% in waters with higher DIC of 50 mg C/L, as compared to similar waters with lower DIC of 10 mg C/L. The Larson Ratio could be a good indicator for iron release depending on the circumstances. Iron release was predicted by molecular radial diffusion modelling that accounted for water quality, scale characteristics, hydraulics, and other condition-related information. The results provided insightful information for water systems that have cast iron pipes and galvanized iron pipes and that might encounter changes in water treatment and water sources. More studies are needed to better understand the cast iron corrosion mechanisms under the examined water chemistries.