1
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Clark GG, Geisler D, Coey EJ, Pollitz LJ, Zaki FR, Huang C, Boppart SA, Nguyen TH. Influence of phosphate on bacterial release from activated carbon point-of-use filters and on biofilm characteristics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 914:169932. [PMID: 38199359 PMCID: PMC11090127 DOI: 10.1016/j.scitotenv.2024.169932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 11/29/2023] [Accepted: 01/03/2024] [Indexed: 01/12/2024]
Abstract
Point-of-use (POU) filters certified to remove lead are often composed of activated carbon and have been shown to release high concentrations of bacteria, including opportunistic pathogens. In this study, we examine the impacts of the common corrosion inhibitor phosphate on biofilm characteristics and the relationship between biofilm structure and bacterial release from POU filters. This knowledge is essential for understanding how best to use the filters and where these filters fit in a system where other lead contamination prevention measures may be in place. We measured the bacterial release from activated carbon POU filters fed with groundwater - a common source of drinking water - with and without phosphate. We used optical coherence tomography (OCT) to quantitatively characterize biofilm growing on activated carbon filter material in which the biofilms were fed groundwater with and without phosphate. Phosphate filters released significantly less (57-87 %) bacteria than groundwater filters, and phosphate biofilms (median thickness: 82-331 μm) grew to be significantly thicker than groundwater biofilms (median thickness: 122-221 μm). The phosphate biofilm roughness ranged from 97 to 142 % of the groundwater biofilm roughness and was significantly greater in most weeks. Phosphate biofilms also had fewer pores per biofilm volume and shorter channels connecting those pores.
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Affiliation(s)
- Gemma G Clark
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, United States of America.
| | - Dietrich Geisler
- Department of Computer Science, Cornell University, United States of America
| | - Evan J Coey
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, United States of America
| | - Lance J Pollitz
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, United States of America
| | - Farzana R Zaki
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States of America
| | - Conghui Huang
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, United States of America
| | - Stephen A Boppart
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States of America; Department of Bioengineering, Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, United States of America; Carle Illinois College of Medicine, United States of America
| | - Thanh H Nguyen
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, United States of America; Carle Illinois College of Medicine, United States of America; Institute of Genomic Biology, University of Illinois at Urbana-Champaign, United States of America
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2
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Spencer-Williams I, Meyer M, DePas W, Elliott E, Haig SJ. Assessing the Impacts of Lead Corrosion Control on the Microbial Ecology and Abundance of Drinking-Water-Associated Pathogens in a Full-Scale Drinking Water Distribution System. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:20360-20369. [PMID: 37970641 DOI: 10.1021/acs.est.3c05272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2023]
Abstract
Increases in phosphate availability in drinking water distribution systems (DWDSs) from the use of phosphate-based corrosion control strategies may result in nutrient and microbial community composition shifts in the DWDS. This study assessed the year-long impacts of full-scale DWDS orthophosphate addition on both the microbial ecology and density of drinking-water-associated pathogens that infect the immunocompromised (DWPIs). Using 16S rRNA gene amplicon sequencing and droplet digital PCR, drinking water microbial community composition and DWPI density were examined. Microbial community composition analysis suggested significant compositional changes after the orthophosphate addition. Significant increases in total bacterial density were observed after orthophosphate addition, likely driven by a 2 log 10 increase in nontuberculous mycobacteria (NTM). Linear effect models confirmed the importance of phosphate addition with phosphorus concentration explaining 17% and 12% of the variance in NTM and L. pneumophila density, respectively. To elucidate the impact of phosphate on NTM aggregation, a comparison of planktonic and aggregate fractions of NTM cultures grown at varying phosphate concentrations was conducted. Aggregation assay results suggested that higher phosphate concentrations cause more disaggregation, and the interaction between phosphate and NTM is species specific. This work reveals new insight into the consequences of orthophosphate application on the DWDS microbiome and highlights the importance of proactively monitoring the DWDS for DWPIs.
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Affiliation(s)
- Isaiah Spencer-Williams
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
| | - Mitchell Meyer
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, United States
| | - William DePas
- Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, United States
| | - Emily Elliott
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
- Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Sarah-Jane Haig
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
- Department of Environmental & Occupational Health, School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, United States
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3
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Tan C, Liu H. Inhibition of Hexavalent Chromium Release from Drinking Water Distribution Systems: Effects of Water Chemistry-Based Corrosion Control Strategies. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:18433-18442. [PMID: 36719710 PMCID: PMC10690716 DOI: 10.1021/acs.est.2c05324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 01/11/2023] [Accepted: 01/12/2023] [Indexed: 06/18/2023]
Abstract
In drinking water distribution systems, the oxidation of zerovalent chromium, Cr(0), in iron corrosion scales by chlorine residual disinfectant is the dominant reaction to form carcinogenic hexavalent chromium, Cr(VI). This study investigates inhibitive corrosion control strategies through adjustments of chemical water parameters (i.e., pH, silicate, phosphate, calcium, and alkalinity) on Cr(VI) formation through oxidation of Cr(0)(s) by free chlorine under drinking water conditions. The results show that an increase in pH, silicate, alkalinity, and calcium suppressed Cr(VI) formation that was mainly attributed to in situ surface precipitation of new Cr(III) solids on the surface of Cr(0)(s), including Cr(OH)3(s), Cr2(SiO3)3(s), CrPO4(s), Cr2(CO3)3(s), and Cr10Ca(CO3)16(s). The Cr(III) surface precipitates were much less reactive with chlorine than Cr(0)(s) and suppressed the Cr redox reactivity. The concentration of surface Cr(III) solids was inversely correlated with the rate constant of Cr(VI) formation. Adding phosphate either promoted or inhibited the Cr(VI) formation, depending on the phosphate concentration. This study provides fundamental insight into the Cr(VI) formation mechanisms via Cr(0) oxidation by chlorine and the importance of surface precipitation of Cr(III) solids with different corrosion control strategies and suggests that increasing the pH/alkalinity and addition of phosphate or silicate can be effective control strategies to minimize Cr(VI) formation.
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Affiliation(s)
- Cheng Tan
- Department of Chemical and Environmental
Engineering, University of California at
Riverside, Riverside, California92521, United States
| | - Haizhou Liu
- Department of Chemical and Environmental
Engineering, University of California at
Riverside, Riverside, California92521, United States
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4
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Liu Y, Liu H, Croue JP, Liu C. CuO Promotes the Formation of Halogenated Disinfection Byproducts during Chlorination via an Enhanced Oxidation Pathway. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:19043-19053. [PMID: 37710978 DOI: 10.1021/acs.est.3c05975] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
Previous studies showed that cupric oxide (CuO) can enhance the formation of trihalomethanes (THMs), haloacetic acids, and bromate during chlorination of bromide-containing waters. In this study, the impact of CuO on the formation kinetics and mechanisms of halogenated disinfection byproducts (DBPs) during chlorination was investigated. CuO does not enhance the formation of DBPs (i.e., 1,1,1-trichloropropanone, chloroform, and trichloroacetaldehyde (TCAL) /dichloroacetonitrile) during chlorination of acetone, 3-oxopentanedioic acid (3-OPA), and aspartic acid, respectively. This indicates that the halogen substitution pathway cannot be enhanced by CuO. Instead, CuO (0.1 g L-1) accelerates the second-order rate constants for reactions of chlorine (HOCl) with TCAL, citric acid, and oxalic acid at pH 8.0 and 21 °C from <0.1 to 29.4, 7.2, and 15.8 M-1 s-1, respectively. Oxidation pathway predominates based on the quantification of oxidation products (e.g., a trichloroacetic acid yield of ∼100% from TCAL) and kinetic modeling. CuO can enhance the formation of DBPs (e.g., THMs, haloacetaldehydes, and haloacetonitriles) during chlorination of model compounds and dissolved organic matter, of which both halogen substitution and oxidation pathways are required. Reaction rate constants of rate-limiting steps (e.g., citric acid to 3-OPA, aromatic ring cleavage) could be enhanced by CuO via an oxidation pathway since CuO-HOCl complex is more oxidative toward a range of substrates than HOCl in water. These findings provide novel insights into the DBP formation pathway in copper-containing distribution systems.
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Affiliation(s)
- Yunsi Liu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Hang Liu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, P. R. China
| | - Jean-Philippe Croue
- Institut de Chimie des Milieux et des Matériaux IC2MP UMR 7285 CNRS, Université de Poitiers, Poitiers 86073, France
| | - Chao Liu
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
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5
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Kimbell LK, LaMartina EL, Kohls S, Wang Y, Newton RJ, McNamara PJ. Impact of corrosion inhibitors on antibiotic resistance, metal resistance, and microbial communities in drinking water. mSphere 2023; 8:e0030723. [PMID: 37681947 PMCID: PMC10597465 DOI: 10.1128/msphere.00307-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 07/17/2023] [Indexed: 09/09/2023] Open
Abstract
Corrosion inhibitors, including zinc orthophosphate, sodium orthophosphate, and sodium silicate, are commonly used to prevent the corrosion of drinking water infrastructure. Metals such as zinc are known stressors for antibiotic resistance selection, and phosphates can increase microbial growth in drinking water distribution systems (DWDS). Yet, the influence of corrosion inhibitor type on antimicrobial resistance in DWDS is unknown. Here, we show that sodium silicates can decrease antibiotic resistant bacteria (ARB) and antibiotic-resistance genes (ARGs), while zinc orthophosphate increases ARB and ARGs in source water microbial communities. Based on controlled bench-scale studies, zinc orthophosphate addition significantly increased the abundance of ARB resistant to ciprofloxacin, sulfonamides, trimethoprim, and vancomycin, as well as the genes sul1, qacEΔ1, an indication of resistance to quaternary ammonium compounds, and the integron-integrase gene intI1. In contrast, sodium silicate dosage at 10 mg/L resulted in decreased bacterial growth and antibiotic resistance selection compared to the other corrosion inhibitor additions. Source water collected from the drinking water treatment plant intake pipe resulted in less significant changes in ARB and ARG abundance due to corrosion inhibitor addition compared to source water collected from the pier at the recreational beach. In tandem with the antibiotic resistance shifts, significant microbial community composition changes also occurred. Overall, the corrosion inhibitor sodium silicate resulted in the least selection for antibiotic resistance, which suggests it is the preferred corrosion inhibitor option for minimizing antibiotic resistance proliferation in DWDS. However, the selection of an appropriate corrosion inhibitor must also be appropriate for the water chemistry of the system (e.g., pH, alkalinity) to minimize metal leaching first and foremost and to adhere to the lead and copper rule. IMPORTANCE Antibiotic resistance is a growing public health concern across the globe and was recently labeled the silent pandemic. Scientists aim to identify the source of antibiotic resistance and control points to mitigate the spread of antibiotic resistance. Drinking water is a direct exposure route to humans and contains antibiotic-resistant bacteria and associated resistance genes. Corrosion inhibitors are added to prevent metallic pipes in distribution systems from corroding, and the type of corrosion inhibitor selected could also have implications on antibiotic resistance. Indeed, we found that sodium silicate can minimize selection of antibiotic resistance while phosphate-based corrosion inhibitors can promote antibiotic resistance. These findings indicate that sodium silicate is a preferred corrosion inhibitor choice for mitigation of antibiotic resistance.
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Affiliation(s)
- Lee K. Kimbell
- Department of Civil, Construction and Environmental Engineering, Marquette University, Milwaukee, Wisconsin, USA
| | - Emily Lou LaMartina
- School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Stan Kohls
- Department of Civil, Construction and Environmental Engineering, Marquette University, Milwaukee, Wisconsin, USA
| | - Yin Wang
- Department of Civil and Environmental Engineering, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Ryan J. Newton
- School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | - Patrick J. McNamara
- Department of Civil, Construction and Environmental Engineering, Marquette University, Milwaukee, Wisconsin, USA
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6
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Zheng S, Lin T, Chen H, Zhang X, Jiang F. Characterization of young biofilm morphology, disinfection byproduct formation potential and toxicity of renewed water supply pipelines by phosphorus release from corroded pipes. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 884:163813. [PMID: 37121323 DOI: 10.1016/j.scitotenv.2023.163813] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 04/18/2023] [Accepted: 04/24/2023] [Indexed: 05/05/2023]
Abstract
The deterioration of drinking water quality due to corrosion of the water supply network has become inevitable and regular renewal of pipes has become a common means of doing so. Severely corroded pipes release certain nutrients (e.g., elemental phosphorus), however, little has been reported on the effect of old pipes on the young biofilm of new pipe sections and on ensuring water safety in the early stages of the water supply. The aim of our study was to model the effect of key phosphorus nutrients released from corroded old pipes on the morphological characteristics of young biofilms in new pipe sections, mediated disinfection byproducts (DBPs) production and their combined toxicity. Based on the experimental results, phosphorus showed significant differences in the morphological characteristics, spatial structure of extracellular polymers (EPS), functional abundance, disinfection byproduct formation potential (DBPsFP) and toxicity of young biofilms. Under residual chlorine (1.0 ± 0.2 mg/L) incubation, the functional abundance of young biofilm metabolism was dominant, particularly amino acid metabolism and carbohydrate metabolism. There is a dynamic balance between the trophic and shedding effects of phosphorus, where concentration changes affect young biofilm morphology and DBPFP. Relatively moderate phosphorus concentrations resulted in the highest density of PN/PS organic precursors in EPS and a clear advantage of DBPFP; relatively high phosphorus conditions had limited promotion of young biofilm, while membrane structure shedding was more pronounced, increasing young biofilm-mediated DBPs production. Nitrogen-containing disinfection byproducts (N-DBPs) in young biofilms had a clear toxicity advantage, with HANs and HNMs being key to controlling cytotoxicity and genotoxicity, respectively.
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Affiliation(s)
- Songyuan Zheng
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Tao Lin
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China.
| | - Han Chen
- Ministry of Education Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Hohai University, Nanjing 210098, PR China; College of Environment, Hohai University, Nanjing 210098, PR China
| | - Xue Zhang
- Suzhou Water Supply Company, Suzhou 215002, China
| | - Fuchun Jiang
- Suzhou Water Supply Company, Suzhou 215002, China
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7
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Huang C, Clark GG, Zaki FR, Won J, Ning R, Boppart SA, Elbanna AE, Nguyen TH. Effects of phosphate and silicate on stiffness and viscoelasticity of mature biofilms developed with simulated drinking water. BIOFOULING 2023; 39:36-46. [PMID: 36847486 PMCID: PMC10065970 DOI: 10.1080/08927014.2023.2177538] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 01/19/2023] [Accepted: 02/02/2023] [Indexed: 05/21/2023]
Abstract
Biofilms, a porous matrix of cells aggregated with extracellular polymeric substances under the influence of chemical constituents in the feed water, can develop a viscoelastic response to mechanical stresses. In this study, the roles of phosphate and silicate, common additives in corrosion control and meat processing, on the stiffness, viscoelasticity, porous structure networks, and chemical properties of biofilm were investigated. Three-year biofilms on PVC coupons were grown from sand-filtered groundwater with or without one of the non-nutrient (silicate) or nutrient additives (phosphate or phosphate blends). Compared with non-nutrient additives, the phosphate and phosphate-blend additives led to a biofilm with the lowest stiffness, most viscoelastic, and more porous structure, including more connecting throats with greater equivalent radii. The phosphate-based additives also led to more organic species in the biofilm matrix than the silicate additive did. This work demonstrated that nutrient additives could promote biomass accumulation but also reduce mechanical stability.
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Affiliation(s)
- Conghui Huang
- Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL
| | - Gemma G. Clark
- Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL
| | - Farzana R. Zaki
- Beckman Institute for Advanced Science and Technology, 405 North Mathews Avenue, Urbana, Illinois 61801, USA
| | - Jungeun Won
- Beckman Institute for Advanced Science and Technology, 405 North Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Bioengineering, University of Illinois Urbana Champaign, 1304 West Springfield Avenue, Urbana, Illinois 61801, USA
| | - Runsen Ning
- Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL
| | - Stephen A. Boppart
- Beckman Institute for Advanced Science and Technology, 405 North Mathews Avenue, Urbana, Illinois 61801, USA
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, 506 South Mathews Avenue, Urbana, Illinois 61801, USA
- Department of Bioengineering, University of Illinois Urbana Champaign, 1304 West Springfield Avenue, Urbana, Illinois 61801, USA
- Department of Electrical and Computer Engineering, University of Illinois Urbana Champaign, 306 North Wright Street, Urbana, Illinois 61801, USA
| | - Ahmed E. Elbanna
- Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL
| | - Thanh H. Nguyen
- Department of Civil and Environmental Engineering, University of Illinois at Urbana Champaign, Urbana, IL
- Institute of Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, United States
- Carle Illinois College of Medicine, University of Illinois at Urbana-Champaign, 506 South Mathews Avenue, Urbana, Illinois 61801, USA
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8
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Spencer-Williams I, Balangoda A, Dabundo R, Elliott E, Haig SJ. Exploring the Impacts of Full-Scale Distribution System Orthophosphate Corrosion Control Implementation on the Microbial Ecology of Hydrologically Connected Urban Streams. Microbiol Spectr 2022; 10:e0215822. [PMID: 36321898 PMCID: PMC9769763 DOI: 10.1128/spectrum.02158-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 10/04/2022] [Indexed: 12/24/2022] Open
Abstract
Many cities across the nation are plagued by lead contamination in drinking water. As such, many drinking water utilities have undertaken lead service line (LSL) replacement to prevent further lead contamination. However, given the urgency of lead mitigation, and the socioeconomic challenges associated with LSL replacement, cities have used phosphate-based corrosion inhibitors (i.e., orthophosphate) alongside LSL replacement. While necessary to ensure public health protection from lead contamination, the addition of orthophosphate into an aging and leaking drinking water system may increase the concentration of phosphate leaching into urban streams characterized by century-old failing water infrastructure. Such increases in phosphate availability may cascade into nutrient and microbial community composition shifts. The purpose of this study was to determine how this occurs and to understand whether full-scale distribution system orthophosphate addition impacts the microbial ecology of urban streams. Through monthly collection of water samples from five urban streams before and after orthophosphate addition, significant changes in microbial community composition (16S rRNA amplicon sequencing) and in the relative abundance of typical freshwater taxa were observed. In addition, key microbial phosphorus and nitrogen metabolism genes (e.g., two component regulatory systems) were predicted to change via BugBase. No significant differences in the absolute abundances of total bacteria, Cyanobacteria, and "Candidatus Accumulibacter" were observed. Overall, the findings from this study provide further evidence that urban streams are compromised by unintentional hydrologic connections with drinking water infrastructure. Moreover, our results suggest that infiltration of phosphate-based corrosion inhibitors can impact urban streams and have important, as-yet-overlooked impacts on urban stream microbial communities. IMPORTANCE Elevated lead levels in drinking water supplies are a public health risk. As such, it is imperative for cities to urgently address lead contamination from aging drinking water supplies by way of lead service line replacements and corrosion control methods. However, when applying corrosion control methods, it is also important to consider the chemical and microbiological effects that can occur in natural settings, given that our water infrastructure is aging and more prone to leaks and breaks. Here, we examine the impacts on the microbial ecology of five urban stream systems before and after full-scale distribution system orthophosphate addition. Overall, the results suggest that infiltration of corrosion inhibitors may impact microbial communities; however, future work should be done to ascertain the true impact to protect both public and environmental health.
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Affiliation(s)
- Isaiah Spencer-Williams
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Anusha Balangoda
- Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Richard Dabundo
- Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Emily Elliott
- Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Sarah-Jane Haig
- Department of Civil and Environmental Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
- Department of Environmental and Occupational Health, School of Public Health, University of Pittsburgh, Pennsylvania, USA
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9
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Shi X, Clark GG, Huang C, Nguyen TH, Yuan B. Chlorine decay and disinfection by-products formation during chlorination of biofilms formed with simulated drinking water containing corrosion inhibitors. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 815:152763. [PMID: 34990663 DOI: 10.1016/j.scitotenv.2021.152763] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/21/2021] [Accepted: 12/25/2021] [Indexed: 06/14/2023]
Abstract
Corrosion inhibitors used to reduce pipe corrosion can alter the physical structure and biochemical components of the biofilm in premise plumbing systems. We studied the effects of corrosion inhibitors on chlorine decay and associated disinfection by-products (DBPs) formation by biofilms grown with simulated drinking water amended with silicate, phosphate, and the phosphate blends. Experiments were conducted with either intact biofilms or biofilm materials dispersed in solution during sonication (referred to as biomass). While there was no significant difference in chlorine decay among biomass from different biofilms, biomass from the phosphate blend biofilm showed the lowest trihalomethane (THMs) and haloacetic acids (HAAs) formation. The chlorine decay rate constants from the biofilm experiment were ranked as: phosphate blends > phosphate ≈ groundwater (GW) > silicate. The kinetics of chlorine decay and formation of DBPs were successfully described by pseudo-first-order kinetics. These fitting parameters were used to predict the DBPs formation in a realistic premise plumbing system. The results showed that biofilm-derived THMs and HAAs increased with increasing chlorine concentration, while THMs and HAAs first increased and then stabilized to a maximum with increasing biofilm total organic carbon (TOC) concentration. In general, the biofilms grown with phosphate-based corrosion inhibitors resulted in lower DBPs formation yield but higher bacterial release, which could potentially increase the risk of user exposure to opportunistic pathogens in drinking water. The silicate biofilms showed the largest yield coefficient of DBPs formation but had the least biomass and lower bacterial release.
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Affiliation(s)
- Xiaoyang Shi
- Xiamen Key Laboratory of Municipal and Industrial Solid Waste Utilization and Pollution Control, College of Civil Engineering, Huaqiao University, Xiamen, Fujian 361021, PR China
| | - Gemma G Clark
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Conghui Huang
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Thanh H Nguyen
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - Baoling Yuan
- Xiamen Key Laboratory of Municipal and Industrial Solid Waste Utilization and Pollution Control, College of Civil Engineering, Huaqiao University, Xiamen, Fujian 361021, PR China.
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10
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Montagnino E, Lytle DA, Rose J, Cwiertny D, Whelton AJ. School and childcare center drinking water: Copper chemistry, health effects, occurrence, and remediation. AWWA WATER SCIENCE 2022; 4:e1270. [PMID: 35865674 PMCID: PMC9286453 DOI: 10.1002/aws2.1270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 01/12/2022] [Accepted: 01/18/2022] [Indexed: 06/15/2023]
Abstract
The study goal was to better understand the risks of elevated copper levels at US schools and childcare centers. Copper health effects, chemistry, occurrence, and remediation actions were reviewed. Of the more than 98,000 schools and 500,000 childcare centers, only 0.2% had copper water testing data in the federal Safe Drinking Water Information System database. Of the facilities designated public water systems, about 13% had reported an exceedance. Schools that were not designated a public water system (PWS) also had exceedances. Few studies document levels in schools and childcare centers. Widely different sampling and remedial actions were reported. Flushing contaminated water was the most evaluated remedial action but was unreliable because copper quickly rebounded when flushing stopped. Building water treatment systems have been used, but some were not capable of making the water safe. The health risk was difficult to determine due to the limited occurrence data and lack of best management practice studies. A national drinking water testing campaign and field studies are recommended.
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Affiliation(s)
| | | | - Joan Rose
- Michigan State UniversityEast LansingMichiganUSA
| | - David Cwiertny
- Department of Civil and Environmental EngineeringUniversity of IowaIowa CityIowaUSA
- Center for Health Effects of Environmental ContaminationUniversity of IowaIowa CityIowaUSA
- Public Policy CenterUniversity of IowaIowa CityIowaUSA
| | - Andrew J. Whelton
- Lyles School of Civil Engineering and Division of Environmental and Ecological EngineeringPurdue UniversityWest LafayetteIndianaUSA
- Center for Plumbing SafetyPurdue UniversityWest LafayetteIndianaUSA
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11
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Swaringen BF, Gawlik E, Kamenov GD, McTigue NE, Cornwell DA, Bonzongo JCJ. Children's exposure to environmental lead: A review of potential sources, blood levels, and methods used to reduce exposure. ENVIRONMENTAL RESEARCH 2022; 204:112025. [PMID: 34508773 DOI: 10.1016/j.envres.2021.112025] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 09/03/2021] [Accepted: 09/06/2021] [Indexed: 06/13/2023]
Abstract
Lead has been used for thousands of years in different anthropogenic activities thanks to its unique properties that allow for many applications such as the manufacturing of drinking water pipes and its use as additives to gasoline and paint. However, knowledge of the adverse impacts of lead on human health has led to its banning from several of its applications, with the main goal of reducing environmental pollution and protecting human health. Human exposure to lead has been linked to different sources of contamination, resulting in high blood lead levels (BLLs) and adverse health implications, primarily in exposed children. Here, we present a summary of a literature review on potential lead sources affecting blood levels and on the different approaches used to reduce human exposure. The findings show a combination of different research approaches, which include the use of inspectors to identify problematic areas in homes, collection and analysis of environmental samples, different lead detection methods (e.g. smart phone applications to identify the presence of lead and mass spectrometry techniques). Although not always the most effective way to predict BLLs in children, linear and non-linear regression models have been used to link BLLs and environmental lead. However, multiple regressions and complex modelling systems would be ideal, especially when seeking results in support of decision-making processes. Overall, lead remains a pollutant of concern and many children are still exposed to it through environmental and drinking water sources. To reduce exposure to lead through source apportionment methods, recent technological advances using high-precision lead stable isotope ratios measured on multi-collector induced coupled plasma mass spectrometry (MC-ICP-MS) instruments have created a new direction for identifying and then eliminating prevalent lead sources associated with high BLLs.
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Affiliation(s)
- Benjamin F Swaringen
- Dept. of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructures and Environment. University of Florida, Gainesville, FL, 32611, USA
| | - Emory Gawlik
- Dept. of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructures and Environment. University of Florida, Gainesville, FL, 32611, USA
| | - George D Kamenov
- Dept. of Geological Sciences, University of Florida, Gainesville, FL 32611, USA
| | - Nancy E McTigue
- Cornwell Engineering Group, 712 Gum Rock Ct, Newport News, VA 23606, USA
| | - David A Cornwell
- Dept. of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructures and Environment. University of Florida, Gainesville, FL, 32611, USA; Cornwell Engineering Group, 712 Gum Rock Ct, Newport News, VA 23606, USA
| | - Jean-Claude J Bonzongo
- Dept. of Environmental Engineering Sciences, Engineering School of Sustainable Infrastructures and Environment. University of Florida, Gainesville, FL, 32611, USA.
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12
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Devine C, Wang F, Edwards M. A Standardized Test Protocol for Evaluation of Scale Reduction Technologies. ENVIRONMENTAL ENGINEERING SCIENCE 2021; 38:1109-1119. [PMID: 34970071 PMCID: PMC8713702 DOI: 10.1089/ees.2021.0047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 08/26/2021] [Indexed: 06/14/2023]
Abstract
Precipitation of calcium carbonate (i.e., scaling) can occur in both traditional tank (electric and gas) and "green" tankless hot water systems that have implications for public health, water and energy sustainability, infrastructure damage, and consumer esthetics. There are many scale reduction devices and technologies that aim to reduce or eliminate such problems, and several standardized methods have been proposed to research their performance with scientific rigor. All of the existing approaches were inherently nonreproducible or could not quantify important aspects of scale deposition, including quantity, location, and deposit durability. Here we develop and vet a Standardized Scaling Test Protocol that overcomes many of these deficiencies, using a laboratory-scale model premise plumbing system and a synthesized synthetic scaling water that could be reproduced in any laboratory. This approach produced 25.1 g of calcium carbonate scaling (95% confidence interval of 20.3-29.8 g, n = 3) in ∼5 days. Illustrative scale reduction for a range of representative technologies, including cation exchange, electrochemical deionization, magnetism, electric field generator, media-induced precipitation, phosphate sacrificial media, and citric acid sacrificial media, ranged from 0% to 100% using the standardized protocol. The general approach was also applied to suitable local natural water with high scaling potential, and similar capabilities were observed.
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Affiliation(s)
- Christina Devine
- Virginia Tech, Civil and Environmental Engineering Department, Blacksburg, Virginia, USA
| | - Fei Wang
- Virginia Tech, Civil and Environmental Engineering Department, Blacksburg, Virginia, USA
| | - Marc Edwards
- Virginia Tech, Civil and Environmental Engineering Department, Blacksburg, Virginia, USA
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13
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Tang M, Lytle D, Botkins J. Accumulation and Release of Arsenic from Cast Iron: Impact of Initial Arsenic and Orthophosphate Concentrations. WATER RESEARCH 2021; 194:116942. [PMID: 33647578 PMCID: PMC8083818 DOI: 10.1016/j.watres.2021.116942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 02/13/2021] [Accepted: 02/15/2021] [Indexed: 05/05/2023]
Abstract
Various iron oxyhydroxide and oxide minerals commonly found in old cast iron pipe scale were shown to exhibit high and similar affinity for arsenate [As(V)] and orthophosphate (PO4) via adsorption, co-precipitation, and other factors. PO4 is a common drinking water corrosion inhibitor. This 7.5-year study examined the accumulation and release of As from an old cast iron pipe scale by changing initial As(V) (0, 75, or 180 µg/L as As) and initial PO4 (0 or 3 mg/L as PO4) levels in the simulated drinking water. The results showed that sites within the iron scale accumulated As with a large capacity and concentrated 27% of the total amount As in water into the scale during the 7.5-year study. When no PO4 was added, the As accumulation followed a linear regression model with an accumulation rate of 0.27/hr (R2 = 0.80, p < 0.001), and higher initial As level of 180 µg/L (vs 75 µg/L) resulted in 2.3-3 times larger As accumulation rate at 0.25 mg/day (vs 0.084-0.11 mg/day). As much as 44 µg/L As was released back to water following the changes in the initial As and PO4 concentrations in water. Addition of 3 mg/L PO4 caused a rapid increase in As release from iron scale that gradually dropped off with time while PO4 was incorporated into the scale and most PO4 remained tightly bound to certain iron scale sites. Proactive measures such as sampling for As in the distribution systems following PO4 corrosion control treatment changes would help identify exposure risks.
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Affiliation(s)
- Min Tang
- ORISE Postdoctoral Fellow at U.S. Environmental Protection Agency. ORD, CESER, WID, DWMB, 26 W. Martin Luther King Drive, Cincinnati, OH 45268, USA
| | - Darren Lytle
- U.S. Environmental Protection Agency. ORD, CESER, WID, DWMB, 26 W. Martin Luther King Drive, Cincinnati, OH 45268, USA.
| | - Jacob Botkins
- Pegasus Technical Services, Inc., Cincinnati Ohio, USA
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Li B, Trueman BF, Rahman MS, Gagnon GA. Controlling lead release due to uniform and galvanic corrosion - An evaluation of silicate-based inhibitors. JOURNAL OF HAZARDOUS MATERIALS 2021; 407:124707. [PMID: 33341575 DOI: 10.1016/j.jhazmat.2020.124707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 11/03/2020] [Accepted: 11/26/2020] [Indexed: 06/12/2023]
Abstract
Silicates have been added to drinking water for decades, both to sequester iron/manganese and as a corrosion control treatment for lead. But the mechanisms by which they might act to limit lead release are not well understood. We evaluated the effects of two silicate formulations on lead release due to uniform and galvanic corrosion over a wide range of pH and dissolved inorganic carbon concentrations. We compared these results to better-characterized systems, with added ortho- or polyphosphate and in an inhibitor-free control. Independent of pH, silicates did not consistently mitigate lead release due to either uniform or galvanic corrosion. Furthermore, lead carbonates appeared to determine lead solubility in the presence of sodium silicate. While silicate treatment did promote the formation of a nanometer-thick silicon layer on lead and a decrease in crystallite size at the scale surface, these changes did not inhibit lead release. But unlike polyphosphate-which is known to form soluble complexes with lead and disperse particulate metals-high ratio silicate did not exacerbate lead release. Metasilicate did exacerbate lead release, especially at pH 7 and 5 mg DIC/L; this suggests that silicate formulation may have an important effect on the dispersion of lead-rich particles.
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Affiliation(s)
- Bofu Li
- Centre for Water Resources Studies, Department of Civil & Resource Engineering, Dalhousie University, 1360 Barrington St., Halifax, Nova Scotia B3H 4R2, Canada.
| | - Benjamin F Trueman
- Centre for Water Resources Studies, Department of Civil & Resource Engineering, Dalhousie University, 1360 Barrington St., Halifax, Nova Scotia B3H 4R2, Canada
| | - Mohammad Shahedur Rahman
- Centre for Water Resources Studies, Department of Civil & Resource Engineering, Dalhousie University, 1360 Barrington St., Halifax, Nova Scotia B3H 4R2, Canada; Civil Engineering Department, College of Engineering, Al Imam Mohammad Ibn Saud Isalamic University, Riyadh, Saudi Arabia
| | - Graham A Gagnon
- Centre for Water Resources Studies, Department of Civil & Resource Engineering, Dalhousie University, 1360 Barrington St., Halifax, Nova Scotia B3H 4R2, Canada
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Li B, Trueman BF, Munoz S, Locsin JM, Gagnon GA. Impact of sodium silicate on lead release and colloid size distributions in drinking water. WATER RESEARCH 2021; 190:116709. [PMID: 33341036 DOI: 10.1016/j.watres.2020.116709] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 11/20/2020] [Accepted: 11/28/2020] [Indexed: 06/12/2023]
Abstract
Sodium silicates have been used in drinking water treatment for decades as sequestrants and corrosion inhibitors. For the latter purpose they are poorly understood, which presents a potential public health risk. We investigated a common sodium silicate formulation as a treatment for lead release and compared it to orthophosphate, a well-established lead corrosion control treatment. We also compared the size distributions of colloids generated in silicate and orthophosphate-treated systems using field flow fractionation with multielement detection. At a moderate dose of 24 mg SiO2/L, sodium silicate yielded a median lead release of 398 µg/L, while orthophosphate yielded 67 µg Pb/L. At an elevated dose of 48 mg SiO2/L, sodium silicate dispersed corrosion scale in cast iron pipe sections and lead service lines, resulting in a substantial release of colloidal iron and lead. In the silicate-treated system, a silicon-rich coating occurred at the lead-water interface, but lead carbonate remained the major corrosion product and appeared to control lead levels. These data suggest that, as a corrosion control treatment for lead, sodium silicate is inferior to orthophosphate in circumneutral pH water with low alkalinity. And, as with polyphosphate, excess silicate can be highly detrimental to controlling lead release.
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Affiliation(s)
- Bofu Li
- Centre for Water Resources Studies, Department of Civil & Resource Engineering, Dalhousie University, 1360 Barrington St., Halifax, Nova Scotia, Canada B3H 4R2
| | - Benjamin F Trueman
- Centre for Water Resources Studies, Department of Civil & Resource Engineering, Dalhousie University, 1360 Barrington St., Halifax, Nova Scotia, Canada B3H 4R2
| | - Sebastian Munoz
- Centre for Water Resources Studies, Department of Civil & Resource Engineering, Dalhousie University, 1360 Barrington St., Halifax, Nova Scotia, Canada B3H 4R2
| | - Javier M Locsin
- Centre for Water Resources Studies, Department of Civil & Resource Engineering, Dalhousie University, 1360 Barrington St., Halifax, Nova Scotia, Canada B3H 4R2
| | - Graham A Gagnon
- Centre for Water Resources Studies, Department of Civil & Resource Engineering, Dalhousie University, 1360 Barrington St., Halifax, Nova Scotia, Canada B3H 4R2.
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16
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Mishrra A, Wang Z, Sidorkiewicz V, Giammar DE. Effect of sodium silicate on lead release from lead service lines. WATER RESEARCH 2021; 188:116485. [PMID: 33045636 DOI: 10.1016/j.watres.2020.116485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/28/2020] [Accepted: 09/29/2020] [Indexed: 06/11/2023]
Abstract
The effect of sodium silicate addition on lead release from lead service lines (LSLs) was investigated using laboratory-based pipe loop experiments with LSLs harvested from a water utility that has one of the Great Lakes as its source water. The LSLs were first conditioned with a synthetic water similar to that of Buffalo Water that matched the major water chemistry that the pipes had experienced in the field; the one exception was the absence of dissolved organic carbon in the synthetic water. After conditioning, the LSLs were used in tests with the same synthetic water and with sodium silicate added to the water for half of the LSLs. In one test sodium silicate addition was performed with adjustment of the pH to maintain it at the same value (pH 7.7) as before addition. In this test sodium silicate effectively reduced the dissolved and particulate lead concentrations in the water within six weeks of treatment. Periodic assessments of the corrosion scales in the pipes found that sodium silicate accumulated throughout the scale thickness and gradually decreased the lead release. In the other test the pH was allowed to increase from 7.7 to 8.8 upon addition of 20 mg/L as SiO2 sodium silicates, and parallel control experiments were performed with the same pH increase made using sodium hydroxide addition. In these tests the lead concentrations decreased in both the silicate-treated and control pipes, and the decreases were not significantly different between the silicate-treated and control pipes.
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Affiliation(s)
- Anushka Mishrra
- Washington University in St. Louis, Department of Energy, Environmental and Chemical Engineering, Campus Box 1180, One Brookings Drive, St. Louis, MO 63130, United States
| | - Ziqi Wang
- Washington University in St. Louis, Department of Energy, Environmental and Chemical Engineering, Campus Box 1180, One Brookings Drive, St. Louis, MO 63130, United States
| | | | - Daniel E Giammar
- Washington University in St. Louis, Department of Energy, Environmental and Chemical Engineering, Campus Box 1180, One Brookings Drive, St. Louis, MO 63130, United States.
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17
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Rosales E, Del Olmo G, Calero Preciado C, Douterelo I. Phosphate Dosing in Drinking Water Distribution Systems Promotes Changes in Biofilm Structure and Functional Genetic Diversity. Front Microbiol 2020; 11:599091. [PMID: 33391216 PMCID: PMC7773730 DOI: 10.3389/fmicb.2020.599091] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 11/24/2020] [Indexed: 01/07/2023] Open
Abstract
Water utilities treat drinking water by adding phosphate to prevent metal dissolution from water pipe work systems and particularly lead poisoning. Phosphate can be a limiting nutrient for microbial biofilms in DWDS, yet its effects on these microbial consortia are not well understood. This research presents results from phosphate dosing experiments using a real scale chlorinated DWDS, comparing standard phosphate concentrations of United Kingdom drinking water (1 mgP/L) with a double dose (2 mgP/L) commonly used in plumbosolvency treatment. Biofilm development during phosphate treatment experiments was monitored using a holistic approach by combining metagenomics analysis, flow cytometry and SEM characterisation. The increase of phosphate levels in drinking water, reduced biofilm cell numbers and promoted the presence of poorly distributed biofilms on inner pipe surfaces. Metagenomics analysis using genetic markers (16S rRNA and ITS2) showed that phosphate influenced biofilm community structure, particularly fungal composition. Whole metagenome sequencing showed that phosphate enrichment favoured the presence of sequencing reads associated to ATPases, ion transporters and DNA-interacting proteins, whilst reads associated to nitrogen metabolism were predominant in control samples. This research brings new knowledge regarding the influence of phosphate treatment on the composition and structure of biofilms within DWDS, and the implications that this might have for the management of these systems.
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Affiliation(s)
- Esther Rosales
- Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, United Kingdom
| | - Gonzalo Del Olmo
- Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, United Kingdom
| | - Carolina Calero Preciado
- Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, United Kingdom
| | - Isabel Douterelo
- Department of Civil and Structural Engineering, The University of Sheffield, Sheffield, United Kingdom
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18
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Zhang S, Shi Q, Chou TM, Christodoulatos C, Korfiatis GP, Meng X. Mechanistic Study of Pb(II) Removal by TiO 2 and Effect of PO 4. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:13918-13927. [PMID: 33171040 DOI: 10.1021/acs.langmuir.0c02388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
As a commercial adsorbent, TiO2 shows a high adsorption capacity for lead (Pb(II)). However, the molecular structure of Pb(II) adsorption on TiO2 is still unknown. Meanwhile, as a widely used corrosion inhibitor, phosphate (PO4) is usually added into drinking water, and its influential mechanism on Pb(II) removal by TiO2 remains unknown. Here, the mechanisms of Pb(II) adsorption on TiO2 and the effect of PO4 were systematically investigated using a combination of spectroscopic analyses and surface complexation modeling. The adsorption structure of Pb(II) on TiO2 was revealed as a tridentate mononuclear configuration by the extended X-ray absorption fine structure (EXAFS) analysis. In the presence of 0.1-5 mg/L PO4, Pb(II) was removed mainly by adsorption on TiO2 rather than precipitation. Ternary complexation between Pb(II) and PO4 on TiO2 surfaces was found based on EXAFS and in situ Fourier transform infrared characterizations. These complexation structures were used to build a surface complexation model to accurately simulate and predict Pb(II) removal under different conditions. This study provides essential information about the mechanisms of Pb(II) removal by TiO2 and develops a model to predict adsorption behaviors, especially in the presence of PO4.
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Affiliation(s)
- Shujuan Zhang
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - Qiantao Shi
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - Tseng-Ming Chou
- Chemical Engineering and Materials Science, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - Christos Christodoulatos
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - George P Korfiatis
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
| | - Xiaoguang Meng
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, New Jersey 07030, United States
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19
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Del Olmo G, Ahmad A, Jensen H, Karunakaran E, Rosales E, Calero Preciado C, Gaskin P, Douterelo I. Influence of phosphate dosing on biofilms development on lead in chlorinated drinking water bioreactors. NPJ Biofilms Microbiomes 2020; 6:43. [PMID: 33097725 PMCID: PMC7585443 DOI: 10.1038/s41522-020-00152-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 09/24/2020] [Indexed: 12/22/2022] Open
Abstract
Phosphate dosing is used by water utilities to prevent plumbosolvency in water supply networks. However, there is a lack of knowledge regarding biofilm formation on lead and plastic materials when phosphate concentrations are modified in drinking water systems. In this study, biofilms were grown over lead coupons and PVC tubes in bioreactors supplied with local drinking water treated to provide different phosphate doses (below 1, 1 and 2 mg/L) over a period of 28 days. A range of commercial iron pellets (GEH104 and WARP) were tested aiming to maintain phosphate levels below the average 1 mg/L found in drinking water. Changes in biofilm community structure in response to three different phosphate treatments were characterised by Illumina sequencing of the 16S rRNA gene for bacteria and the ITS2 gene for fungi. Scanning electron microscopy was used to visualise physical differences in biofilm development in two types of materials, lead and PVC. The experimental results from the kinetics of phosphate absorption showed that the GEH104 pellets were the best option to, in the long term, reduce phosphate levels while preventing undesirable turbidity increases in drinking water. Phosphate-enrichment promoted a reduction of bacterial diversity but increased that of fungi in biofilms. Overall, higher phosphate levels selected for microorganisms with enhanced capabilities related to phosphorus metabolism and heavy metal resistance. This research brings new insights regarding the influence of different phosphate concentrations on mixed-species biofilms formation and drinking water quality, which are relevant to inform best management practices in drinking water treatment.
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Affiliation(s)
- Gonzalo Del Olmo
- Department of Civil and Structural Engineering, University of Sheffield, Sheffield, UK
| | - Arslan Ahmad
- KWR Water Cycle Research Institute, Groningenhaven 7, 3433, PE, Nieuwegein, The Netherlands
- KTH-International Groundwater Arsenic Research Group, Department of Sustainable Development, Environmental Science and Engineering, KTH Royal Institute of Technology, Teknikringen 10B, SE-100 44, Stockholm, Sweden
- Department of Environmental Technology, Wageningen University and Research (WUR), Droevendaalsesteeg 4, 6708, PB, Wageningen, The Netherlands
| | - Henriette Jensen
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
| | - Esther Karunakaran
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
| | - Esther Rosales
- Department of Civil and Structural Engineering, University of Sheffield, Sheffield, UK
| | | | | | - Isabel Douterelo
- Department of Civil and Structural Engineering, University of Sheffield, Sheffield, UK.
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20
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Interactive Effects of Copper Pipe, Stagnation, Corrosion Control, and Disinfectant Residual Influenced Reduction of Legionella pneumophila during Simulations of the Flint Water Crisis. Pathogens 2020; 9:pathogens9090730. [PMID: 32899686 PMCID: PMC7559348 DOI: 10.3390/pathogens9090730] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/28/2020] [Accepted: 08/31/2020] [Indexed: 01/28/2023] Open
Abstract
Flint, MI experienced two outbreaks of Legionnaires' Disease (LD) during the summers of 2014 and 2015, coinciding with use of Flint River as a drinking water source without corrosion control. Using simulated distribution systems (SDSs) followed by stagnant simulated premise (i.e., building) plumbing reactors (SPPRs) containing cross-linked polyethylene (PEX) or copper pipe, we reproduced trends in water chemistry and Legionella proliferation observed in the field when Flint River versus Detroit water were used before, during, and after the outbreak. Specifically, due to high chlorine demand in the SDSs, SPPRs with treated Flint River water were chlorine deficient and had elevated L. pneumophila numbers in the PEX condition. SPPRs with Detroit water, which had lower chlorine demand and higher residual chlorine, lost all culturable L. pneumophila within two months. L. pneumophila also diminished more rapidly with time in Flint River SPPRs with copper pipe, presumably due to the bacteriostatic properties of elevated copper concentrations caused by lack of corrosion control and stagnation. This study confirms hypothesized mechanisms by which the switch in water chemistry, pipe materials, and different flow patterns in Flint premise plumbing may have contributed to observed LD outbreak patterns.
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21
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The impact of metal pipe materials, corrosion products, and corrosion inhibitors on antibiotic resistance in drinking water distribution systems. Appl Microbiol Biotechnol 2020; 104:7673-7688. [DOI: 10.1007/s00253-020-10777-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/29/2020] [Accepted: 07/05/2020] [Indexed: 02/07/2023]
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22
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Shi Q, Zhang S, Ge J, Wei J, Christodoulatos C, Korfiatis GP, Meng X. Lead immobilization by phosphate in the presence of iron oxides: Adsorption versus precipitation. WATER RESEARCH 2020; 179:115853. [PMID: 32388052 DOI: 10.1016/j.watres.2020.115853] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 04/14/2020] [Accepted: 04/18/2020] [Indexed: 06/11/2023]
Abstract
As a commonly used corrosion inhibitor, phosphate (PO4) has a complicated effect on the fate and transport of lead (Pb) in drinking water systems. While the formation of pyromorphite has been recognized to be the major driving force of the Pb immobilization mechanism, the role of adsorption on iron oxides is still not clear. This study aims to clarify the contributions of adsorption and precipitation to Pb removal in a system containing both iron oxides and PO4. A combination of batch experiments, X-ray absorption spectroscopy, infrared spectroscopy, and electron spectroscopy was employed to distinguish the adsorbed and precipitated Pb species. The results indicated that the adsorption of Pb on iron oxides still occurred even when the solution was supersaturated to pyromorphite (i.e., 5 mg/L P with 0.1-30 mg/L Pb in 0.01 M NaCl solution at neutral pH). In the tap water containing 0.92 mg/L P and 1 mg/L Pb, adsorption on iron oxides contributed more (62-67%) than precipitation (33-38%) in terms of Pb removal. Surprisingly, the pre-formed pyromorphite is transformed to adsorbed species after mixing with iron oxides in water for 24 h. The illustration of this transformation is important to understand the immobilization mechanisms and transport behaviors of Pb in drinking water systems after the utilization of PO4.
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Affiliation(s)
- Qiantao Shi
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ, 07030, United States
| | - Shujuan Zhang
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ, 07030, United States
| | - Jie Ge
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ, 07030, United States
| | - Jinshan Wei
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ, 07030, United States
| | - Christos Christodoulatos
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ, 07030, United States
| | - George P Korfiatis
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ, 07030, United States
| | - Xiaoguang Meng
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ, 07030, United States. http://
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23
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Bae Y, Pasteris JD, Giammar DE. Impact of orthophosphate on lead release from pipe scale in high pH, low alkalinity water. WATER RESEARCH 2020; 177:115764. [PMID: 32305699 DOI: 10.1016/j.watres.2020.115764] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/02/2020] [Accepted: 03/26/2020] [Indexed: 06/11/2023]
Abstract
This study explored the ability of orthophosphate addition to limit lead release from lead service lines delivering high pH, low alkalinity water. We built pipe loop reactors with lead pipes harvested from Providence, RI, and we operated them with high pH and low alkalinity water of a composition similar to that in Providence. Orthophosphate addition decreased the release of both dissolved and particulate lead to the water. The most substantial decreases in total lead concentrations occurred after 15 weeks of orthophosphate addition, which was associated with the formation of calcium-lead-phosphorus (Ca-Pb-P) solids as part of the pipe scale. Pre-existing hydrocerussite (Pb3(CO3)2(OH)2(s)) in the scale of the lead pipe appeared to promote the formation of a Ca-Pb-P solid similar to phosphohedyphane (Ca2Pb3(PO4)3(Cl,F,OH)(s)). Continuous orthophosphate addition was also associated with the formation of a calcium phosphate solid with features like those of fluorapatite (Ca5(PO4)3F(s)) on the outermost layer of the scale. Through promoting the formation of these new solids within and on top of the scales, orthophosphate addition limited release of dissolved and particulate lead. These results demonstrate the ability of orthophosphate to control lead release at higher pH conditions than those for which it has typically been used. In addition to the formation of phosphate solids, PbO2(s), which was not present on the as-received pipes, was formed due to the constant supply of free chlorine in the laboratory-scale experiment.
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Affiliation(s)
- Yeunook Bae
- Department of Energy, Environmental, and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri, 63130, United States
| | - Jill D Pasteris
- Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, Missouri, 63130, United States
| | - Daniel E Giammar
- Department of Energy, Environmental, and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri, 63130, United States.
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Li G, Bae Y, Mishrra A, Shi B, Giammar DE. Effect of Aluminum on Lead Release to Drinking Water from Scales of Corrosion Products. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:6142-6151. [PMID: 32338882 DOI: 10.1021/acs.est.0c00738] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
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.
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Affiliation(s)
- Guiwei Li
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yeunook Bae
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Anushka Mishrra
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
| | - Baoyou Shi
- Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Daniel E Giammar
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri 63130, United States
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Abstract
Nitrification is a major issue that utilities must address if they utilize chloramines as a secondary disinfectant. Nitrification is the oxidation of free ammonia to nitrite which is then further oxidized to nitrate. Free ammonia is found in drinking water systems as a result of overfeeding at the water treatment plant (WTP) or as a result of the decomposition of monochloramine. Premise plumbing systems (i.e., the plumbing systems within buildings and homes) are characterized by irregular usage patterns, high water age, high temperature, and high surface-to-volume ratios. These characteristics create ideal conditions for increased chloramine decay, bacterial growth, and nitrification. This review discusses factors within premise plumbing that are likely to influence nitrification, and vice versa. Factors influencing, or influenced by, nitrification include the rate at which chloramine residual decays, microbial regrowth, corrosion of pipe materials, and water conservation practices. From a regulatory standpoint, the greatest impact of nitrification within premise plumbing is likely to be a result of increased lead levels during Lead and Copper Rule (LCR) sampling. Other drinking water regulations related to nitrifying parameters are monitored in a manner to reduce premise plumbing impacts. One way to potentially control nitrification in premise plumbing systems is through the development of building management plans.
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Bae Y, Pasteris JD, Giammar DE. The Ability of Phosphate To Prevent Lead Release from Pipe Scale When Switching from Free Chlorine to Monochloramine. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:879-888. [PMID: 31834790 DOI: 10.1021/acs.est.9b06019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
For lead pipes that contain PbO2(s) as a major component of their scales, a change in the residual disinfectant from free chlorine to monochloramine can destabilize the PbO2(s) and result in dramatic increases in aqueous lead concentrations. Such a scenario occurred in Washington, D.C., in late 2000. That problem was ultimately addressed by the addition of phosphate as a corrosion inhibitor, but it took several months for lead levels to drop below regulatory values. This study sought to determine whether adding phosphate prior to switching the disinfectant could mitigate lead release. Using synthetic tap water and new lead pipes, we developed a set of lead pipes with scales rich in PbO2(s) and then studied their response to a change from free chlorine to monochloramine. Total lead concentrations remained below 10 μg/L for pipes that received phosphate prior to and during the switch. In contrast, total lead concentrations increased from less than 5 μg/L to more than 150 μg/L as a result of the disinfectant switch when phosphate was not present. Characterization of the pipe scales demonstrated that plattnerite (β-PbO2(s)) was the dominant component of the scale prior to the switch, and that the scale gradually transformed into one containing a lead phosphate solid chemically similar to phosphohedyphane (Ca2Pb3(PO4)3(Cl,F,OH)(s)) when phosphate was present.
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Fang C, Ding S, Gai S, Xiao R, Wu Y, Geng B, Chu W. Effect of oxoanions on oxidant decay, bromate and brominated disinfection by-product formation during chlorination in the presence of copper corrosion products. WATER RESEARCH 2019; 166:115087. [PMID: 31541789 DOI: 10.1016/j.watres.2019.115087] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 09/11/2019] [Accepted: 09/12/2019] [Indexed: 06/10/2023]
Abstract
The present study investigated the effect of oxoanions on catalytic behaviour of copper corrosion products (CCPs) during chlorination of bromide-containing waters. Three types of oxoanions (carbonate, sulphate, and phosphate) and four types of CCPs (Cu2+, Cu(OH)2, Cu2O, and CuO) were involved in investigation and the effect of oxoanions concentration was also examined. The result indicated that carbonate and sulphate slightly inhibited oxidant decay in the presence of CCPs, but the formation of brominated disinfection by-products (Br-DBPs) remained largely unchanged. In contrast, the presence of phosphate (0.2-1 mM) almost eliminated the catalytic effect of Cu2+. For CCP solids (i.e. Cu(OH)2, Cu2O, and CuO), phosphate preferentially inhibited the formation of bromate rather than Br-DBPs. Despite the catalysis by CCP solids was reduced to some extent, the oxidant decay rate and bromate and Br-DBP formation were still significantly higher than blank groups, even at high phosphate concentration. By testing different addition scheme (simultaneous/sequential addition), it was proposed that phosphate was a strong competitor for hypohalites, rapidly destroying CCPs-hypohalites complexes on some adsorption sites. However, there were some specific sites that can only be adsorbed by hypohalites, leading to the incomplete inhibition of phosphate. Finally, the inhibition effect of phosphate on CCPs catalysis was tested in real water matrix. For Cu2+, higher reduction of bromate and Br-DBPs was found in raw water rather than filtered water, while converse pattern was true for Cu(OH)2 and Cu2O, and this discrepancy can be ascribed to the difference in catalytic mechanism between Cu2+ and CCP solids.
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Affiliation(s)
- Chao Fang
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China; International Joint Research Center for Sustainable Urban Water System, Tongji University, Shanghai, 200092, China
| | - Shunke Ding
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China; International Joint Research Center for Sustainable Urban Water System, Tongji University, Shanghai, 200092, China
| | - Shibo Gai
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China; International Joint Research Center for Sustainable Urban Water System, Tongji University, Shanghai, 200092, China
| | - Rong Xiao
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China; International Joint Research Center for Sustainable Urban Water System, Tongji University, Shanghai, 200092, China
| | - Yinan Wu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China
| | - Bing Geng
- Shanghai National Engineering Research Center of Urban Water Resources Co., Ltd, Shanghai, 200082, China
| | - Wenhai Chu
- State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China; International Joint Research Center for Sustainable Urban Water System, Tongji University, Shanghai, 200092, China.
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28
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Shi Q, Terracciano A, Zhao Y, Wei C, Christodoulatos C, Meng X. Evaluation of metal oxides and activated carbon for lead removal: Kinetics, isotherms, column tests, and the role of co-existing ions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 648:176-183. [PMID: 30114588 DOI: 10.1016/j.scitotenv.2018.08.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Revised: 08/01/2018] [Accepted: 08/02/2018] [Indexed: 05/19/2023]
Abstract
Activated carbon (AC) is commonly used in faucet and pitcher filters for lead (Pb(II)) removal in homes. This study evaluated the Pb(II) removal performance of AC and metal oxides (e.g. Fe(OH)3 and TiO2), as well as the co-existing ions' effect on Pb(II) removal. Results showed that metal oxides had higher adsorption capacity (28.9-51.5 mg/g) than AC (21.2 mg/g). Pb(II) was inner-spherically adsorbed onto both AC and metal oxides surfaces. Among various metal ions, calcium (Ca(II)) demonstrated dramatic effects on Pb(II) removal ability of AC, while it had no effect on Pb(II) adsorption by metal oxides. This difference resulted from the inner- and outer-sphere adsorption of Ca(II) on AC and metal oxides, respectively. The presence of orthophosphate (orth-P) and sulfate enhanced Pb(II) removal by those three adsorbents, whereas carbonate and silicate had negligible effect on Pb(II) adsorption. Interestingly, while the orth-P was usually used as corrosion inhibitor because of the formation of lead-phosphate coprecipitate, we found that the enhanced effect of orth-P on Pb(II) removal was mainly due to the synergistic adsorption. This study provides valuable information for the selection of effective adsorbents for Pb(II) removal and is helpful for understanding the roles of co-existing ions on it.
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Affiliation(s)
- Qiantao Shi
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, United States
| | - Amalia Terracciano
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, United States
| | - Ying Zhao
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, United States; State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China
| | - Chaoyang Wei
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, United States; Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Christos Christodoulatos
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, United States
| | - Xiaoguang Meng
- Center for Environmental Systems, Stevens Institute of Technology, Hoboken, NJ 07030, United States.
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29
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Jarvis P, Quy K, Macadam J, Edwards M, Smith M. Intake of lead (Pb) from tap water of homes with leaded and low lead plumbing systems. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 644:1346-1356. [PMID: 30743847 DOI: 10.1016/j.scitotenv.2018.07.064] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Revised: 07/04/2018] [Accepted: 07/05/2018] [Indexed: 06/09/2023]
Abstract
Methods of quantifying consumer exposure to lead in drinking water are increasingly of interest worldwide, especially those that account for consumer drinking habits and the semi-random nature of water lead release from plumbing systems. A duplicate intake protocol was developed in which individuals took a sub-sample from each measured drink they consumed in the home over three days in both winter and summer. The protocol was applied in two different water company regional areas (WC1 and WC2), selected to represent high risk situations in England, with the presence or absence of lead service pipes or phosphate corrosion control. Consumer exposure to lead was highest in properties with lead service pipes, served by water without P dosing. The protocol indicated that a small number of individuals in the study, all from homes with lead service pipes, consumed lead at levels that exceeded current guidance from the European Food Standards Agency. Children's potential blood lead levels (BLLs) were estimated using the Internal Exposure Uptake Biokinetic model (IEUBK). The IEUBK model predicted that up to 46% of children aged 0-7 years old may have elevated BLLs (>5 μg/dL) when consuming the worst case drinking water quality (>99%ile). Estimating blood lead levels using the IEUBK model for more typical lead concentrations in drinking water identified in this study (between 0.1 and 7.1 μg/L), predicts that elevated BLLs may affect a small proportion of children between 0 and 7 years old.
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Affiliation(s)
- Peter Jarvis
- Cranfield Water Science Institute, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK.
| | - Katie Quy
- Thomas Coram Research Unit, UCL Institute of Education, 20 Bedford Way, London WC1H 0AA, UK
| | - Jitka Macadam
- Cranfield Water Science Institute, Cranfield University, Cranfield, Bedfordshire MK43 0AL, UK
| | - Marc Edwards
- The Charles E. Via, Jr. Department of Civil & Environmental Engineering, Virginia Tech, Blacksburg, VA 24061, USA
| | - Marjorie Smith
- Thomas Coram Research Unit, UCL Institute of Education, 20 Bedford Way, London WC1H 0AA, UK
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30
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Hernandez Ruiz S, Perdrial J, Segraves D. Evaluation of corrosion control products on a distribution system through crowdsourcing. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:34487-34495. [PMID: 30311115 DOI: 10.1007/s11356-018-3361-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 09/27/2018] [Indexed: 06/08/2023]
Abstract
Crowdsourcing of citizens was used to determine the effectiveness of corrosion control in a water distribution system. This study examines the frequency and severity of "Red Water" complaints over a period of 4 years, and two different corrosion control chemicals, polyphosphate and zinc orthophosphate. The data revealed that the frequency of Red Water complaints was higher when using zinc orthophosphate while the severity (higher iron) was higher when using polyphosphates. Varying the dose of zinc orthophosphate to account for cold months induced a greater number of customer complaints. Moreover, corrosion coupons studies suggest similar performance of both corrosion inhibitor products. The corrosion and complaints might be driven by microbial-induced processes in which diatoms might play a significant role.
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Affiliation(s)
| | - Julia Perdrial
- Department of Geology, The University of Vermont, Delehanty Hall, Room 213C, Burlington, VT, 05405, USA
| | - Dustin Segraves
- Water Quality Division Superintendent, 420 W Main St., Oklahoma City, OK, 73102, USA
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31
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Ng DQ, Chen CY, Lin YP. A new scenario of lead contamination in potable water distribution systems: Galvanic corrosion between lead and stainless steel. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 637-638:1423-1431. [PMID: 29801235 DOI: 10.1016/j.scitotenv.2018.05.114] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 05/06/2018] [Accepted: 05/09/2018] [Indexed: 06/08/2023]
Abstract
Lead pipe has been banned for distributing drinking water in the 1980s and partial replacement of lead pipes with stainless steel pipes has been practiced in many Asian countries. Due to the different potentials of lead and stainless steel, galvanic corrosion may take place. The extent of lead release and effects of water chemistry on this process, however, are largely unknown. The objectives of this study are to characterize lead release resulting from galvanic connection between lead and stainless steel, the effects of pH, chloride and sulfate concentrations on this process, and the effectiveness of using orthophosphate to mitigate this problem. The experiments were conducted by connecting aged lead pipes to stainless steel fittings and placing the couple in different water conditions. The results of this study demonstrated that lead release significantly accelerated when lead and stainless steel were galvanically connected and the rate of lead release accelerated with decreasing pH and increasing chloride-to-sulfate mass ratio (CSMR). Orthophosphate could effectively reduce lead release but CSMR needs to be considered since water with a higher CSMR still caused more lead release when galvanic corrosion took place.
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Affiliation(s)
- Ding-Quan Ng
- Department of Environmental Engineering and Management, Chaoyang University of Technology, No. 168, Jifeng E. Rd, Wufeng District, Taichung 41349, Taiwan
| | - Che-Yu Chen
- Graduate Institute of Environmental Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan
| | - Yi-Pin Lin
- Graduate Institute of Environmental Engineering, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan.
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32
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Pieper KJ, Martin R, Tang M, Walters L, Parks J, Roy S, Devine C, Edwards MA. Evaluating Water Lead Levels During the Flint Water Crisis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:8124-8132. [PMID: 29932326 DOI: 10.1021/acs.est.8b00791] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
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.
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Affiliation(s)
- Kelsey J Pieper
- Civil and Environmental Engineering , Virginia Polytechnic Institute and State University , 418 Durham Hall , Blacksburg , Virginia 24061 , United States
| | - Rebekah Martin
- Civil and Environmental Engineering , Virginia Polytechnic Institute and State University , 418 Durham Hall , Blacksburg , Virginia 24061 , United States
| | - Min Tang
- Civil and Environmental Engineering , Virginia Polytechnic Institute and State University , 418 Durham Hall , Blacksburg , Virginia 24061 , United States
| | - LeeAnne Walters
- Citizen Scientist, 212 Browning Avenue , Flint , Michigan 48507 , United States
| | - Jeffrey Parks
- Civil and Environmental Engineering , Virginia Polytechnic Institute and State University , 418 Durham Hall , Blacksburg , Virginia 24061 , United States
| | - Siddhartha Roy
- Civil and Environmental Engineering , Virginia Polytechnic Institute and State University , 418 Durham Hall , Blacksburg , Virginia 24061 , United States
| | - Christina Devine
- Civil and Environmental Engineering , Virginia Polytechnic Institute and State University , 418 Durham Hall , Blacksburg , Virginia 24061 , United States
| | - Marc A Edwards
- Civil and Environmental Engineering , Virginia Polytechnic Institute and State University , 418 Durham Hall , Blacksburg , Virginia 24061 , United States
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33
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Stets EG, Lee CJ, Lytle DA, Schock MR. Increasing chloride in rivers of the conterminous U.S. and linkages to potential corrosivity and lead action level exceedances in drinking water. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 613-614:1498-1509. [PMID: 28797521 PMCID: PMC7390064 DOI: 10.1016/j.scitotenv.2017.07.119] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 07/05/2017] [Accepted: 07/13/2017] [Indexed: 05/26/2023]
Abstract
Corrosion in water-distribution systems is a costly problem and controlling corrosion is a primary focus of efforts to reduce lead (Pb) and copper (Cu) in tap water. High chloride concentrations can increase the tendency of water to cause corrosion in distribution systems. The effects of chloride are also expressed in several indices commonly used to describe the potential corrosivity of water, the chloride-sulfate mass ratio (CSMR) and the Larson Ratio (LR). Elevated CSMR has been linked to the galvanic corrosion of Pb whereas LR is indicative of the corrosivity of water to iron and steel. Despite the known importance of chloride, CSMR, and LR to the potential corrosivity of water, monitoring of seasonal and interannual changes in these parameters is not common among water purveyors. We analyzed long-term trends (1992-2012) and the current status (2010-2015) of chloride, CSMR, and LR in order to investigate the short and long-term temporal variability in potential corrosivity of US streams and rivers. Among all sites in the trend analyses, chloride, CSMR, and LR increased slightly, with median changes of 0.9mgL-1, 0.08, and 0.01, respectively. However, urban-dominated sites had much larger increases, 46.9mgL-1, 2.50, and 0.53, respectively. Median CSMR and LR in urban streams (4.01 and 1.34, respectively) greatly exceeded thresholds found to cause corrosion in water distribution systems (0.5 and 0.3, respectively). Urbanization was strongly correlated with elevated chloride, CSMR, and LR, especially in the most snow-affected areas in the study, which are most likely to use road salt. The probability of Pb action-level exceedances (ALEs) in drinking water facilities increased along with raw surface water CSMR, indicating a statistical connection between surface water chemistry and corrosion in drinking water facilities. Optimal corrosion control will require monitoring of critical constituents reflecting the potential corrosivity in surface waters.
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Affiliation(s)
- E G Stets
- U.S. Geological Survey, National Research Program, Boulder, CO 80303, USA.
| | - C J Lee
- U.S. Geological Survey, Kansas Water Science Center, Lawrence, KS 66049, USA
| | - D A Lytle
- U.S. Environmental Protection Agency, Water Supply and Water Resources Division, Cincinnati, OH 45268, USA
| | - M R Schock
- U.S. Environmental Protection Agency, Water Supply and Water Resources Division, Cincinnati, OH 45268, USA
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34
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Jereb G, Poljšak B, Eržen I. Contribution of Drinking Water Softeners to Daily Phosphate Intake in Slovenia. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:E1186. [PMID: 28984825 PMCID: PMC5664687 DOI: 10.3390/ijerph14101186] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Revised: 10/03/2017] [Accepted: 10/04/2017] [Indexed: 12/14/2022]
Abstract
The cumulative phosphate intake in a typical daily diet is high and, according to several studies, already exceeds recommended values. The exposure of the general population to phosphorus via drinking water is generally not known. One of the hidden sources of phosphorus in a daily diet is sodium polyphosphate, commonly used as a drinking water softener. In Slovenia, softening of drinking water is carried out exclusively within the internal (household) drinking water supply systems to prevent the accumulation of limescale. The aim of the study was to determine the prevalence of sodium phosphates in the drinking water in Slovenia in different types of buildings, to determine residents' awareness of the presence of chemical softeners in their drinking water, and to provide an exposure assessment on the phosphorus intake from drinking water. In the current study, the presence of phosphates in the samples of drinking water was determined using a spectrophotometric method with ammonium molybdate. In nearly half of the samples, the presence of phosphates as water softeners was confirmed. The measured concentrations varied substantially from 0.2 mg PO4/L to 24.6 mg PO4/L. Nearly 70% of the respondents were not familiar with the exact data on water softening in their buildings. It follows that concentrations of added phosphates should be controlled and the consumers should be informed of the added chemicals in their drinking water. The health risks of using sodium polyphosphate as a drinking water softener have not been sufficiently investigated and assessed. It is highly recommended that proper guidelines and regulations are developed and introduced to protect human health from adverse effects of chemicals in water intended for human consumption.
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Affiliation(s)
- Gregor Jereb
- Faculty of Health Sciences, University of Ljubljana, Zdravstvena pot 5, 1000 Ljubljana, Slovenia.
| | - Borut Poljšak
- Faculty of Health Sciences, University of Ljubljana, Zdravstvena pot 5, 1000 Ljubljana, Slovenia.
| | - Ivan Eržen
- Department of Environmental Health, National Institute of Public Health, Trubarjeva 2, 1000 Ljubljana, Slovenia.
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35
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Wang F, Devine CL, Edwards MA. Effect of Corrosion Inhibitors on In Situ Leak Repair by Precipitation of Calcium Carbonate in Potable Water Pipelines. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:8561-8568. [PMID: 28661668 DOI: 10.1021/acs.est.7b01380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Corrosion inhibitors can affect calcium carbonate precipitation and associated in situ and in-service water distribution pipeline leak repair via clogging. Clogging of 150 μm diameter leak holes represented by glass capillary tubes, in recirculating solutions that are supersaturated with calcite (Ωcalcite = 13), demonstrated that Zn, orthophosphate, tripolyphosphate, and hexametaphosphate corrosion/scaling inhibitors hinder clogging but natural organic matter (NOM) has relatively little impact. Critical concentrations of phosphates that could inhibit leak repair over the short-term in one water tested were: tripolyphophate (0.05 mg/L as P) < hexametaphosphate (0.1 mg/L) < orthophosphate (0.3 mg/L). Inhibitor blends (Zn+orthophosphate and Zn+NOM+orthophosphate) had stronger inhibitory effects compared to each inhibitor (Zn, orthophosphate or NOM) alone, whereas Zn+NOM showed a lesser inhibitory effect than its individual component (NOM) alone due to formation of smaller CaCO3 particles with a much more negative zeta-potential. Overall, increased dosing of corrosion inhibitors is probably reducing the likelihood of scaling and in-service leak repair via clogging with calcium carbonate solids in potable water systems.
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Affiliation(s)
- Fei Wang
- The Charles E. Via, Jr. Department of Civil & Environmental Engineering, Virginia Tech Blacksburg, Virginia 24061, United States
| | - Christina L Devine
- The Charles E. Via, Jr. Department of Civil & Environmental Engineering, Virginia Tech Blacksburg, Virginia 24061, United States
| | - Marc A Edwards
- The Charles E. Via, Jr. Department of Civil & Environmental Engineering, Virginia Tech Blacksburg, Virginia 24061, United States
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36
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Trueman BF, Sweet GA, Harding MD, Estabrook H, Bishop DP, Gagnon GA. Galvanic Corrosion of Lead by Iron (Oxyhydr)Oxides: Potential Impacts on Drinking Water Quality. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:6812-6820. [PMID: 28557454 DOI: 10.1021/acs.est.7b01671] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Lead exposure via drinking water remains a significant public health risk; this study explored the potential effects of upstream iron corrosion on lead mobility in water distribution systems. Specifically, galvanic corrosion of lead by iron (oxyhydr)oxides was investigated. Coupling an iron mineral cathode with metallic lead in a galvanic cell increased lead release by 531 μg L-1 on average-a 9-fold increase over uniform corrosion in the absence of iron. Cathodes were composed of spark plasma sintered Fe3O4 or α-Fe2O3 or field-extracted Fe3O4 and α-FeOOH. Orthophosphate immobilized oxidized lead as insoluble hydroxypyromorphite, while humic acid enhanced lead mobility. Addition of a humic isolate increased lead release due to uniform corrosion by 81 μg L-1 and-upon coupling lead to a mineral cathode-release due to galvanic corrosion by 990 μg L-1. Elevated lead in the presence of humic acid appeared to be driven by complexation, with 208Pb and UV254 size-exclusion chromatograms exhibiting strong correlation under these conditions (R2average = 0.87). A significant iron corrosion effect was consistent with field data: lead levels after lead service line replacement were greater by factors of 2.3-4.7 at sites supplied by unlined cast iron distribution mains compared with the alternative, lined ductile iron.
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Affiliation(s)
- Benjamin F Trueman
- Department of Civil & Resource Engineering, Dalhousie University , Halifax, Nova Scotia B3H 4R2, Canada
| | - Gregory A Sweet
- Department of Mechanical Engineering, Dalhousie University , Halifax, Nova Scotia B3H 4R2, Canada
| | - Matthew D Harding
- Department of Mechanical Engineering, Dalhousie University , Halifax, Nova Scotia B3H 4R2, Canada
| | - Hayden Estabrook
- Department of Civil & Resource Engineering, Dalhousie University , Halifax, Nova Scotia B3H 4R2, Canada
| | - D Paul Bishop
- Department of Mechanical Engineering, Dalhousie University , Halifax, Nova Scotia B3H 4R2, Canada
| | - Graham A Gagnon
- Department of Civil & Resource Engineering, Dalhousie University , Halifax, Nova Scotia B3H 4R2, Canada
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Kogo A, Payne SJ, Andrews RC. Comparison of three corrosion inhibitors in simulated partial lead service line replacements. JOURNAL OF HAZARDOUS MATERIALS 2017; 329:211-221. [PMID: 28178636 DOI: 10.1016/j.jhazmat.2017.01.039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 01/16/2017] [Accepted: 01/21/2017] [Indexed: 06/06/2023]
Abstract
Partial lead service line replacements (PLSLR) were simulated using five recirculating pipe loops treated with either zinc orthophosphate (1mg/L as P), orthophosphate (1mg/L as P) or sodium silicate (10mg/L). Two pipe loops served as inhibitor-free (Pb-Cu) and galvanic free (Pb-PVC) controls. Changes in water quality (CSMR [0.2 or 1], conductivity [330mS/cm or 560mS/cm], chlorine [1.4mg/L]) were not observed to provide a significant impact on lead or copper release, although galvanic corrosion was shown to be a driving factor. Generally, both orthophosphate and zinc orthophosphate provided better corrosion control for both total and dissolved lead (30min, 6h, 65h) and copper (30min, 6h), when compared to either the inhibitor-free control or the sodium silicate treated system. This work highlights the importance of understanding the complex interplay of corrosion inhibitors on particulate and dissolved species when considering both lead and copper.
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Affiliation(s)
- Aki Kogo
- Department of Civil Engineering, University of Toronto,35 St. George Street, Toronto, ON M5S 1A4, Canada
| | - Sarah Jane Payne
- Department of Civil Engineering, University of Toronto,35 St. George Street, Toronto, ON M5S 1A4, Canada.
| | - Robert C Andrews
- Department of Civil Engineering, University of Toronto,35 St. George Street, Toronto, ON M5S 1A4, Canada
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Trueman BF, Gagnon GA. Understanding the Role of Particulate Iron in Lead Release to Drinking Water. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:9053-60. [PMID: 27468089 DOI: 10.1021/acs.est.6b01153] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Lead service lines (LSLs) are a major source of drinking water lead, and high iron levels are frequently observed along with elevated lead release. A model distribution system, dosed with orthophosphate, was used to evaluate the effect of corroded iron distribution mains on lead release from recovered LSLs. Lead release was higher by 96 μg L(-1), on average, from LSLs supplied by corroded iron compared to the inert reference material (PVC). This effect may be explained by deposition of semiconducting iron oxide particles within LSLs. When galvanic cells with lead and magnetite (Fe3O4) electrodes were short-circuited, lead release increased 8-fold and a current averaging 26 μA was observed. In effluent from LSLs with an upstream iron main, colloidal lead and iron occurred in the same size fraction-possibly due to release of colloidal particles from LSL corrosion scale enriched with iron. Under these circumstances, high molecular weight (>669 kDa) (208)Pb and (56)Fe elution profiles, observed via size-exclusion chromatography, were highly correlated (average R(2) = 0.97). Increasing orthophosphate from 0.5 to 1.0 mg L(-1) (as PO4(3-)) accompanied an average reduction in lead release of 6 μg L(-1) month(-1) but did not significantly reduce the effect of an upstream iron main.
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Affiliation(s)
- Benjamin F Trueman
- Department of Civil & Resource Engineering, Dalhousie University , 1360 Barrington St., Halifax, Nova Scotia Canada B3H 4R2
| | - Graham A Gagnon
- Department of Civil & Resource Engineering, Dalhousie University , 1360 Barrington St., Halifax, Nova Scotia Canada B3H 4R2
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Masters S, Welter GJ, Edwards M. Seasonal Variations in Lead Release to Potable Water. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:5269-77. [PMID: 27078082 DOI: 10.1021/acs.est.5b05060] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The influence of temperature on the solubility of representative lead solids present in drinking-water systems and the lead release to potable water was examined. Temperature had surprisingly little effect on the dissolution of cerrusite, hydrocerussite, chloropyromorphite, lead orthophosphate, and lead oxide solids; however, in the presence of natural organic matter, lead oxide dissolution was 36 times greater (36 versus 1277 ppb) at 20 °C compared to 4 °C due to accelerated reductive dissolution. The solubility of plumbonacrite was three times higher at 20 °C compared to 4 °C (260 versus 92 ppb). In full-scale pipe rigs using harvested lead service lines in Washington, DC and Providence, RI, dissolved lead release increased by as much as 2-3 times, and particulate lead increased 2-6 times in the summer versus winter. In four of the eight homes sampled in Providence, RI, dissolved lead levels were three times higher during the summer compared to the winter, and five homes had copper levels that were 2.5-15 times greater in the winter. These studies demonstrate a need to better understand how lead service line scales vary because patterns of release and temperature dependency sometimes vary markedly, even within the same distribution system.
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Affiliation(s)
- Sheldon Masters
- Via Department of Civil and Environmental Engineering, Virginia Tech , Blacksburg, Virginia 24061, United States
| | - Gregory J Welter
- O'Brien and Gere Engineers, Inc. , Bowie, Maryland 20716, United States
| | - Marc Edwards
- Via Department of Civil and Environmental Engineering, Virginia Tech , Blacksburg, Virginia 24061, United States
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Gooddy DC, Lapworth DJ, Ascott MJ, Bennett SA, Heaton THE, Surridge BWJ. Isotopic Fingerprint for Phosphorus in Drinking Water Supplies. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:9020-8. [PMID: 26042958 DOI: 10.1021/acs.est.5b01137] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Phosphate dosing of drinking water supplies, coupled with leakage from distribution networks, represents a significant input of phosphorus to the environment. The oxygen isotope composition of phosphate (δ(18)OPO4), a novel stable isotope tracer for phosphorus, offers new opportunities to understand the importance of phosphorus derived from sources such as drinking water. We report the first assessment of δ(18)OPO4 within drinking water supplies. A total of 40 samples from phosphate-dosed distribution networks were analyzed from across England and Wales. In addition, samples of the source orthophosphoric acid used for dosing were also analyzed. Two distinct isotopic signatures for drinking water were identified (average = +13.2 or +19.7‰), primarily determined by δ(18)OPO4 of the source acid (average = +12.4 or +19.7‰). Dependent upon the source acid used, drinking water δ(18)OPO4 appears isotopically distinct from a number of other phosphorus sources. Isotopic offsets from the source acid ranging from -0.9 to +2.8‰ were observed. There was little evidence that equilibrium isotope fractionation dominated within the networks, with offsets from temperature-dependent equilibrium ranging from -4.8 to +4.2‰. While partial equilibrium fractionation may have occurred, kinetic effects associated with microbial uptake of phosphorus or abiotic sorption and dissolution reactions may also contribute to δ(18)OPO4 within drinking water supplies.
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Affiliation(s)
- Daren C Gooddy
- †British Geological Survey, Maclean Building, Wallingford, Oxfordshire OX10 8BB, United Kingdom
| | - Dan J Lapworth
- †British Geological Survey, Maclean Building, Wallingford, Oxfordshire OX10 8BB, United Kingdom
| | - Matthew J Ascott
- †British Geological Survey, Maclean Building, Wallingford, Oxfordshire OX10 8BB, United Kingdom
| | - Sarah A Bennett
- ‡Natural Environment Research Council (NERC) Isotope Geosciences Laboratory (NIGL), British Geological Survey, Keyworth, Nottingham NG12 5GG, United Kingdom
| | - Timothy H E Heaton
- ‡Natural Environment Research Council (NERC) Isotope Geosciences Laboratory (NIGL), British Geological Survey, Keyworth, Nottingham NG12 5GG, United Kingdom
| | - Ben W J Surridge
- §Lancaster Environment Centre, Lancaster University, Bailrigg, Lancaster, LA1 4YQ, United Kingdom
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Noel JD, Wang Y, Giammar DE. Effect of water chemistry on the dissolution rate of the lead corrosion product hydrocerussite. WATER RESEARCH 2014; 54:237-246. [PMID: 24576699 DOI: 10.1016/j.watres.2014.02.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 01/30/2014] [Accepted: 02/01/2014] [Indexed: 06/03/2023]
Abstract
Hydrocerussite (Pb3(CO3)2(OH)2) is widely observed as a corrosion product in drinking water distribution systems. Its equilibrium solubility and dissolution rate can control lead concentrations in drinking water. The dissolution rate of hydrocerussite was investigated as a function of pH, dissolved inorganic carbon (DIC), and orthophosphate concentrations at conditions relevant to drinking water distribution using continuously stirred tank reactors (CSTRs). In the absence of DIC and orthophosphate, the dissolution rate decreased with increasing pH. Addition of DIC inhibited the dissolution of hydrocerussite. The addition of orthophosphate significantly decreased the dissolution rate of hydrocerussite. At conditions with orthophosphate and without DIC, a lead(II) phosphate solid hydroxylpyromorphite (Pb5(PO4)3OH) was observed after reaction, and orthophosphate's inhibitory effect can be attributed to the formation of this low-solubility lead(II) phosphate solid. In the presence of both orthophosphate and DIC, no lead(II) phosphate solid was observed, but the rate was still lowered by the presence of orthophosphate, which might be due to the adsorption of orthophosphate to block reactive sites on the hydrocerussite surface. For systems in which hydroxylpyromorphite was present, the steady-state effluent lead concentrations from the CSTRs were close to the predicted equilibrium solubility of hydroxylpyromorphite. In the absence of orthophosphate rapid equilibration of hydrocerussite was observed.
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Affiliation(s)
| | - Yin Wang
- Department of Energy, Environmental, and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, USA
| | - Daniel E Giammar
- Department of Energy, Environmental, and Chemical Engineering, Washington University in St. Louis, St. Louis, MO, USA.
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Wang Y, Mehta V, Welter GJ, Giammar DE. Effect of connection methods on lead release from galvanic corrosion. ACTA ACUST UNITED AC 2013. [DOI: 10.5942/jawwa.2013.105.0088] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Yin Wang
- Department of Civil and Environmental Engineering; University of Illinois; Urbana-Champaign
| | - Vrajesh Mehta
- Department of Energy, Environmental, and Chemical Engineering; Washington University in St. Louis; St. Louis Mo
| | | | - Daniel E. Giammar
- Department of Energy, Environmental, and Chemical Engineering; Washington University in St. Louis; St. Louis Mo
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Jang HJ, Choi YJ, Ro HM, Ka JO. Effects of phosphate addition on biofilm bacterial communities and water quality in annular reactors equipped with stainless steel and ductile cast iron pipes. J Microbiol 2012; 50:17-28. [DOI: 10.1007/s12275-012-1040-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Accepted: 09/16/2011] [Indexed: 10/28/2022]
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Parks JL, Kashyap A, Atassi A, Schneider O, Edwards M. Effect of zinc and orthophosphate corrosion inhibitors on cement-based pipes. ACTA ACUST UNITED AC 2012. [DOI: 10.5942/jawwa.2012.104.0001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- Jeffrey L. Parks
- Department of Civil and Environmental Engineering; Virginia Polytechnic Institute and State University; Blacksburg Va
| | | | | | | | - Marc Edwards
- Department of Civil and Environmental Engineering; Virginia Polytechnic Institute and State University; Blacksburg Va
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Hsieh MK, Li H, Chien SH, Monnell JD, Chowdhury I, Dzombak DA, Vidic RD. Corrosion control when using secondary treated municipal wastewater as alternative makeup water for cooling tower systems. WATER ENVIRONMENT RESEARCH : A RESEARCH PUBLICATION OF THE WATER ENVIRONMENT FEDERATION 2010; 82:2346-2356. [PMID: 21214028 DOI: 10.2175/106143010x12681059117094] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Secondary treated municipal wastewater is a promising alternative to fresh water as power plant cooling water system makeup water, especially in arid regions. Laboratory and field testing was conducted in this study to evaluate the corrosiveness of secondary treated municipal wastewater for various metals and metal alloys in cooling systems. Different corrosion control strategies were evaluated based on varied chemical treatment. Orthophosphate, which is abundant in secondary treated municipal wastewater, contributed to more than 80% precipitative removal of phosphorous-based corrosion inhibitors. Tolyltriazole worked effectively to reduce corrosion of copper (greater than 95% inhibition effectiveness). The corrosion rate of mild steel in the presence of free chlorine 1 mg/L (as Cl2) was approximately 50% higher than in the presence of monochloramine 1 mg/L (as Cl2), indicating that monochloramine is a less corrosive biocide than free chlorine. The scaling layers observed on the metal alloys contributed to corrosion inhibition, which could be seen by comparing the mild steel 21-day average corrosion rate with the last 5-day average corrosion rate, the latter being approximately 50% lower than the former.
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Affiliation(s)
- Ming-Kai Hsieh
- Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
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Fang W, Hu J, Ong S. Influence of phosphorus on biofilm formation in model drinking water distribution systems. J Appl Microbiol 2009; 106:1328-35. [DOI: 10.1111/j.1365-2672.2008.04099.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Park SK, Kim YK, Choi SC. Response of microbial growth to orthophosphate and organic carbon influx in copper and plastic based plumbing water systems. CHEMOSPHERE 2008; 72:1027-1034. [PMID: 18495203 DOI: 10.1016/j.chemosphere.2008.04.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2007] [Revised: 04/02/2008] [Accepted: 04/03/2008] [Indexed: 05/26/2023]
Abstract
Consequences of orthophosphate addition for corrosion control in water distribution pipes with respect to microbial growth were investigated using batch and dynamic tests. Batch tests showed that the release of copper in either low or high organic carbon content water was decreased by 69% and 56% with addition 206 microg PO(4)-P, respectively. Dosing of orthophosphate against corrosion did not increase microbial growth potential in the water and in the biofilm in both corroded and uncorroded systems receiving tap water with a low content of organic carbon and of biodegradable organic fraction. However, in tap water having a high concentration of organic carbon from acetate addition, orthophosphate addition promoted the growth of bacteria, allowed more bacteria to assemble on corroded and uncorroded surfaces, and increased the consumption of organic carbon. Orthophosphate consumption did not exceed 1% of the amount of easily biodegradable organic carbon required for microbial growth, and the orthophosphate demand for corrosion control greatly exceeded the nutritional requirement of microbial growth. The results of the dynamic tests demonstrated that there was a significant effect of interaction between biodegradable organic carbon and orthophosphate on biofilm growth, whereby the effect of orthophosphate flux on microbial growth was dependent on the levels of biodegradable organic carbon. Controlling an easily biodegradable organic carbon would be therefore necessary to minimize the microbial growth potential induced by orthophosphate-based anticorrosion treatment.
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Affiliation(s)
- Se-Keun Park
- Department of Environmental Engineering, Kangwon National University, 192-1 Hyoja-dong, Chuncheon, Gangwon-do 200-701, Republic of Korea.
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Zhang Y, Griffin A, Edwards M. Nitrification in premise plumbing: role of phosphate, pH and pipe corrosion. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2008; 42:4280-4. [PMID: 18605545 DOI: 10.1021/es702483d] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Nitrification in PVC premise plumbing is a weak function of pH over the range 6.5--8.5 and is insensitive to phosphate concentrations 5--1000 ppb. Lead pipe enhanced nitrification relative to PVC, consistent with expectations that nitrifiers could benefit from ammonia recycled from nitrate via lead corrosion. Relatively new copper pipe (< 1.5-years-old) did not allow nitrifiers to establish, but nitrifiers gradually colonized over a period of months in brass pipes when copper concentrations were reduced by pH adjustment or orthophosphate. Nitrifiers were inhibited by trace copper, but not by lead levels up to 8000 ppb. In some systems using chloramines, brass in plastic plumbing systems might be more susceptible to lead/copper leaching, and accelerated dezincification, due to lower pH values resulting from nitrification.
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Affiliation(s)
- Yan Zhang
- 418 Durham Hall, Civil and Environmental Engineering Department Virginia Tech, Blacksburg, Virginia 24061, USA
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50
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Hozalski RM, Esbri-Amador E, Chen CF. Comparison of stannous chloride and phosphate for lead corrosion control. ACTA ACUST UNITED AC 2005. [DOI: 10.1002/j.1551-8833.2005.tb10847.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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