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We describe 10 patients with nonkeratitis Acanthamoeba infection who reported performing nasal rinsing before becoming ill. All were immunocompromised, 7 had chronic sinusitis, and many used tap water for nasal rinsing. Immunocompromised persons should be educated about safe nasal rinsing to prevent free-living ameba infections.
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Amebiasis , Nariz , Humanos , Estados Unidos/epidemiología , Amebiasis/epidemiología , Huésped InmunocomprometidoRESUMEN
In September 2021, a total of 25 patients diagnosed with COVID-19 developed acute melioidosis after (median 7 days) admission to a COVID-19 field hospital in Thailand. Eight nonpotable tap water samples and 6 soil samples were culture-positive for Burkholderia pseudomallei. Genomic analysis suggested contaminated tap water as the likely cause of illness.
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Burkholderia pseudomallei , COVID-19 , Melioidosis , Humanos , Melioidosis/epidemiología , Tailandia/epidemiología , Burkholderia pseudomallei/genética , AguaRESUMEN
Single-particle inductively coupled plasma mass spectrometry (spICP-MS) has been used to characterize metallic nanoparticles (NPs) assuming that all NPs are spherical and composed of pure element. However, environmental NPs generally do not meet these criteria, suggesting that spICP-MS may underestimate their true sizes. This study employed a system hyphenating the atomizer (ATM), differential mobility analyzer (DMA), and spICP-MS to characterize metallic NPs in tap water. Its performance was validated by using reference Au nanoparticles (AuNPs) and Ag-shelled AuNPs. The hyphenated system can determine the actual size and metal composition of both NPs with additional heating after ATM, while stand-alone spICP-MS misidentified the Ag-shelled AuNPs as smaller individual AgNPs and AuNPs. Dissolved metal ions could introduce artifact NPs after heating but could be eliminated by centrifugation. The hyphenated system was applied to characterize Fe-containing and Pb-containing NPs resulting from the corrosion of plumbing materials in tap water. The mode sizes of Fe-containing and Pb-containing NPs were determined to be 110 and 100 nm and the particle number concentrations were determined to be 4.99 × 107 and 1.40 × 106 #/mL, respectively. Cautions should be paid to potential changes in particle size induced by heating for metallic NPs with a low melting point or a high organic content.
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Nanopartículas del Metal , Nanopartículas del Metal/química , Oro/química , Plomo , Ingeniería Sanitaria , Corrosión , Nebulizadores y Vaporizadores , Tamaño de la Partícula , AguaRESUMEN
OBJECTIVES: To explore the association between drinking water sources and cognitive functioning among older adults residing in rural China. METHODS: Data were extracted from the 2008-2018 Chinese Longitudinal Healthy Longevity Survey. Drinking water sources were categorized according to whether purification measures were employed. The Chinese version of the Mini-Mental State Examination was used for cognitive functioning assessment, and the score of <24 was considered as having cognitive dysfunction. Cox regression analyses were conducted to derive hazard ratios (HRs) and 95% confidence intervals (CIs) for the effects of various drinking water sources, changes in such sources, and its interaction with exercise on cognition dysfunction. RESULTS: We included 2304 respondents aged 79.67 ± 10.02 years; of them, 1084 (44.49%) were men. Our adjusted model revealed that respondents consistently drinking tap water were 21% less likely to experience cognitive dysfunction compared with those drinking untreated water (HR = 0.79, 95% CI: 0.70-0.90). Respondents transitioning from natural to tap water showed were 33% less likely to experience cognitive dysfunction (HR = 0.67, 95% CI: 0.58-0.78). Moreover, the HR (95% CI) for the interaction between drinking tap water and exercising was 0.86 (0.75-1.00) when compared with that between drinking untreated water and not exercising. All results adjusted for age, occupation, exercise, and body mass index. CONCLUSIONS: Prolonged tap water consumption and switching from untreated water to tap water were associated with a decreased risk of cognitive dysfunction in older individuals. Additionally, exercising and drinking tap water was synergistically associated with the low incidence of cognitive dysfunction. These findings demonstrate the importance of prioritizing drinking water health in rural areas, indicating that purified tap water can enhance cognitive function among older adults.
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Disfunción Cognitiva , Agua Potable , Población Rural , Humanos , Masculino , Anciano , Femenino , China/epidemiología , Población Rural/estadística & datos numéricos , Anciano de 80 o más Años , Disfunción Cognitiva/epidemiología , Disfunción Cognitiva/etiología , Estudios Longitudinales , Ejercicio Físico , Cognición/fisiología , Modelos de Riesgos Proporcionales , Abastecimiento de AguaRESUMEN
Monitoring studies have demonstrated the wide presence of N, N'-substituted p-phenylenediamine-derived quinones (PPDQs) in environmental matrices. The general population may be potentially exposed to PPDQs through the consumption of tap water. While, the existence of PPDQs in tap water has not been well examined. To fill this gap, in this study we collected tap water samples from Hangzhou, China, and examined seven homologues of PPDQs in collected samples. All target PPDQs were identified in the collected tap water samples, with distinct detection frequencies (38-89%). PPDQs detected in tap water was dominated by N-(1, 3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPDQ; mean 0.56 ng/L, < LOD-4.0 ng/L). The profiles of PPDQs concentrations in tap water from the four districts of Hangzhou city were slightly different. The daily intake (DI) was found highest for 6PPDQ (mean 14-22 pg/kg bw/day, median 10-15 pg/kg bw/day) through tap water intake. The relatively higher DIs of various PPDQs were displayed for infants (mean 10-22 pg/kg bw/day, median 6.5-15 pg/kg bw/day), relative to the children (8.0-18 pg/kg bw/day, 5.4-12 pg/kg bw/day) and adults (6.7-14 pg/kg bw/day, 4.5-10 pg/kg bw/day). These data are crucial for assessing the overall human exposure to PPDQs. This study first, to our knowledge, reveals the concentrations and profiles of PPDQs in tap water.
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It is well known that municipal drinking water may be the cause of gastrointestinal illness (GII) outbreaks, but it is still unclear to what extent drinking water contributes to endemic GII. To explore this, we conducted a prospective cohort study among 6,955 adults in five municipalities in Sweden, collecting monthly GII episodes and mean daily cold drinking water consumption through SMS (Short Message Service). When the association between drinking water consumption and GII (all symptoms) and acute gastrointestinal illness (AGI, vomiting and/or three loose stools during a 24-h period) were assessed, there were indications that the association departed from linearity, following a unimodal shape. Among consumers in surface water areas, the highest risk of GII and AGI was generally seen among the average consumers, while the opposite was seen among groundwater consumers. The association however also seemed to be affected by neighbouring communities. The results of the study indicate that there is indeed an association between drinking water consumption and endemic GII, but the nature of this association is complex and likely affected by multiple factors, for example, water source type in the home and degree of exposure to drinking water from additional sources.
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Agua Potable , Enfermedades Gastrointestinales , Suecia/epidemiología , Humanos , Agua Potable/análisis , Agua Potable/química , Adulto , Masculino , Enfermedades Gastrointestinales/epidemiología , Enfermedades Gastrointestinales/etiología , Femenino , Estudios Prospectivos , Persona de Mediana Edad , Anciano , Estudios de Cohortes , Adulto Joven , Enfermedades Endémicas , Abastecimiento de AguaRESUMEN
BACKGROUND: The delivery of safe drinking water has high public health relevance, as reflected in the Sustainable Development Goals (SDG6). Several precautionary actions have reduced the burden associated with infectious diseases in high-income countries; however, pollution in source waters, inadequate disinfection, and premise plumbing, along with an increased awareness that intrusion in the drinking water distribution system, represents risk factors for gastrointestinal illness linked to consume of drinking water. Sporadic cases of waterborne infections are expected to be underreported since a sick person is less likely to seek healthcare for a self-limiting gastrointestinal infection. Hence, knowledge on the true burden of waterborne diseases is scarce. The primary aim with the present study was to estimate the risk of gastrointestinal illness associated with drinking tap water in Norway. METHODS: We conducted a 12-month prospective cohort study where participants were recruited by telephone interview after invitation based on randomised selection. A start up e-survey were followed by 12 monthly SMS questionnaires to gather information on participants characteristics and drinking tap water (number of 0.2L glasses per day), incidence, duration and symptoms associated with gastrointestinal illness. Associations between the exposure of drinking tap water and the outcome of risk of acute gastrointestinal illness (AGI) were analysed with linear mixed effects models. Age, sex, education level and size of the drinking water supply were identified as potential confounders and included in the adjusted model. RESULTS: In total, 9,946 persons participated in this cohort study, accounting for 11.5% of all invited participants. According to the data per person and month (99,446 monthly submissions), AGI was reported for 5,508 person-months (5.5 per 100 person-months). Severe AGI was reported in 819 person-months (0.8 per 100 person-months). Our study estimates that 2-4% of AGI in Norway is attributable to drinking tap water. CONCLUSIONS: This is the largest cohort study in Norway estimating the burden of self-reported gastrointestinal infections linked to the amount of tap water drunk in Norway. The data indicate that waterborne AGI is not currently a burden in Norway, but the findings need to be used with caution. The importance of continued efforts and investments in the maintenance of drinking water supplies in Norway to address the low burden of sporadic waterborne cases and to prevent future outbreaks needs to be emphasised.
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Agua Potable , Enfermedades Gastrointestinales , Humanos , Noruega/epidemiología , Masculino , Femenino , Estudios Prospectivos , Adulto , Persona de Mediana Edad , Enfermedades Gastrointestinales/epidemiología , Enfermedades Gastrointestinales/etiología , Adulto Joven , Anciano , Adolescente , Medición de Riesgo , Factores de Riesgo , Enfermedades Transmitidas por el Agua/epidemiología , Encuestas y Cuestionarios , Abastecimiento de AguaRESUMEN
The study objective was to identify correlates of tap water consumption among adolescents. French-speaking adolescents from the province of Québec (Canada) were recruited in person and online from March to July 2023 using diverse recruitment strategies. Water consumption was measured using the validated French version of a questionnaire specifically designed to measure adolescents' beverage intake. Participants answered an online survey on their attitude towards tap and bottled water which also measured individual and environmental factors that can influence tap water consumption. A total of 218 adolescents (14-17 years; 55.5% female) completed the survey. On average, 79.2% of adolescents' water intake came from tap and 33.5% of them consumed exclusively tap water. Thinking that bottled water is more convenient than tap water was a significant correlate of adolescents' tap water consumption (OR=0.70; 95% CI: 0.51, 0.95; p=0.0219). Adolescents who believed that bottled water is more convenient than tap water were less likely to consume exclusively tap water. Public health interventions aimed at promoting adolescents' tap water should strive to make tap water intake be perceived as convenient as bottled water, such as encouraging teenagers to always carry along a reusable water bottle, installing drinking fountains in popular public areas, and increasing the visibility of such fountains.
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As an oxidant, deodorant and bleaching agent, the hypochlorous acid (HClO) and hypochlorite (ClO- ) are widely used in corrosion inhibitors, textile dyes, pharmaceutical intermediates and in our daily lives. However, excess usage or aberrant accumulation of ClO- leads to tissue damage or some diseases and even cancer. Therefore, it is necessary to develop a fluorescent probe that specifically identifies ClO- . In this article, we synthesized a deep-red xanthene-based fluorescent probe (XA-CN). The strong electron deficient group dicyano endows the probe XA-CN deep-red fluorescent emission with high solubility, selectivity and sensitivity for ClO- detection. Studies showed that the probe demonstrated turn-off fluorescence (643 nm) at the presence of ClO- in dimethylsulfoxide/phosphate-buffered saline 1:1 (pH 9) solution with a limit of detection of 1.64 µM. Detection mechanism investigation revealed that the electron deficient group -CN and the hydroxyl group was oxidized into aldehyde or carbonyl groups at the presence of ClO- , resulting ultraviolet-visible absorption of the probe blue shifted and turned-off fluorescence. Furthermore, XA-CN was successfully used for the detection of ClO- in tap water samples.
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Colorantes Fluorescentes , Ácido Hipocloroso , Agua , Microscopía Fluorescente , OxidantesRESUMEN
Bio-cement is a green and energy-saving building material that has attracted much attention in the field of ecological environment and geotechnical engineering in recent years. The aim of this study is to investigate the use of bio-cement (enzyme-induced calcium carbonate precipitation-EICP) in combination with admixtures for the improvement of desert sands, which can effectively improve the mechanical properties of desert sands and is particularly suitable for sand-rich countries. In addition, the suitability of tap water in bio-cement was elucidated and the optimum ratio of each influencing factor when tap water is used as a solvent was derived. The results showed that peak values of unconfined compressive strength (maximum increase of about 130 times), shear strength (increase of 27.09%), calcium carbonate precipitation value (increase of about 4.39 times), and permeability (decrease of about 93.72 times) were obtained in the specimens modified by EICP combined with admixture as compared to the specimens modified by EICP only. The incorporation of skimmed milk powder, though significantly increasing the strength, is not conducive to cost control. The microscopic tests show that the incorporation of admixtures can provide nucleation sites for EICP, thus improving the properties of desert sand. This work can provide new research ideas for cross-fertilization between the disciplines of bio-engineering, ecology, and civil engineering.
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Carbonato de Calcio , Arena , Arena/química , Carbonato de Calcio/química , Materiales de Construcción , Clima Desértico , Fuerza CompresivaRESUMEN
N-nitrosamines in reservoir water have drawn significant attention because of their carcinogenic properties. Karst reservoirs containing dissolved organic matter (DOM) are important drinking water sources and are susceptible to contamination because of the fast flow of various contaminants. However, it remains unclear whether N-nitrosamines and their precursor, DOM, spread in karst reservoirs. Therefore, this study quantitatively investigated the occurrence and sources of N-nitrosamines based on DOM properties in three typical karst reservoirs and their corresponding tap water. The results showed that N-nitrosamines were widely spread, with detection frequencies > 85%. Similar dominant compounds, including N-nitrosodimethylamine, N-nitrosomethylethylamine, N-nitrosopyrrolidine, and N-nitrosodibutylamine, were observed in reservoirs and tap water, with average concentrations of 4.7-8.9 and 2.8-6.7 ng/L, respectively. The average carcinogenic risks caused by these N-nitrosamines were higher than the risk level of 10-6. Three-dimensional fluorescence excitation-emission matrix modeling revealed that DOM was composed of humus-like component 1 (C1) and protein-like component 2 (C2). Fluorescence indicators showed that DOM in reservoir water was mainly affected by exogenous pollution and algal growth, whereas in tap water, DOM was mainly affected by microbial growth with strong autopoietic properties. In the reservoir water, N-nitrosodiethylamine and N-nitrosopiperidine were significantly correlated with C2 and biological indicators, indicating their endogenously generated sources. Based on the principal component analysis and multiple linear regression methods, five sources of N-nitrosamines were identified: agricultural pollution, microbial sources, humus sources, degradation processes, and other factors, accounting for 46.8%, 36.1%, 7.82%, 8.26%, and 0.96%, respectively. For tap water, two sources, biological reaction processes, and water distribution systems, were identified, accounting for 75.7% and 24.3%, respectively. Overall, this study presents quantitative information on N-nitrosamines' sources based on DOM properties in typical karst reservoirs and tap water, providing a basis for the safety of drinking water for consumers.
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Agua Potable , Nitrosaminas , Contaminantes Químicos del Agua , Humanos , Agua Potable/análisis , Contaminantes Químicos del Agua/análisis , Nitrosaminas/análisis , Carcinógenos/análisis , Suelo , China , CarcinogénesisRESUMEN
To date, there is an increased risk to public health and the environment due to the presence of pharmaceutically active compounds within drinking water supply and distribution networks. Owing to this, a direct injection-HPLC/MS-MS method was developed for the simultaneous determination of 16 active pharmaceutical compounds in tap water samples: amoxicillin, ampicillin, cephalexin, cefotaxime, cefuroxime, ciprofloxacin, clarithromycin, clindamycin, chloramphenicol, cyproterone, erythromycin, flutamide, spironolactone, sulfamethoxazole, tamoxifen, and trimethoprim. Limits of detection (LOD) ranged from 0.2 to 6.0 µg/L while quantification limits (LOQ) from 0.3 to 20 µg/L. Recovery percentages were between 70 and 125%. Total analysis time was short, with all compounds being resolved in less than 2.1 min. Of the 22 tap water samples collected and analyzed, the highest concentrations corresponded to amoxicillin (147 µg/L) and ciprofloxacin (44 µg/L). The findings could set a precedent for establishing safe levels of these compounds and increasing standards for tap water quality in this region.
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Agua Potable , Monitoreo del Ambiente , Espectrometría de Masas en Tándem , Contaminantes Químicos del Agua , Contaminantes Químicos del Agua/análisis , Cromatografía Líquida de Alta Presión , Agua Potable/química , Monitoreo del Ambiente/métodos , Preparaciones Farmacéuticas/análisis , Límite de Detección , Ciprofloxacina/análisis , Abastecimiento de Agua , Amoxicilina/análisisRESUMEN
Background: Modena's Local Health Authority (AUSL) is a public service with more than 5,000 employees. In its facilities, drinking water is available as tap water. However, disposable plastic bottles are also widely used, thus increasing plastic waste. Study design and methods: In the present study, we aimed to investigate employees' drinking habits through an ad hoc 10-item online questionnaire, which was administered in spring 2023. Results: Of the 584 participants (10.8% response rate), 75% of workers reported drinking less than 1.5 liters of water per day. In addition, 74% of workers brought water from home, while 62% used disposable plastic containers bought in the workplace or outside. When asked if they would appreciate a water refilling station in the workplace, whether that would induce them to consume less plastic and to drink more water, 91%, 82%, and 72% of workers said "yes", respectively. By installing water coolers, the estimated mean number of plastic bottles spared every day at the AUSL would be about 6,000. Conclusions: Our data shed light on most employees' perceived need for alternative sources of drinking water, not only in order to drink more for health benefits, but also to reduce plastic usage in favor of reusable, more environmentally friendly materials.
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Tap water is not sterile, and its use in home medical devices can result in infections from waterborne pathogens. However, many participants in a recent survey in the United States said tap water could safely be used for home medical devices. These results can inform communication materials to reduce the high consequence of infections.
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Percepción , Agua , Humanos , Estados Unidos , Encuestas y Cuestionarios , Abastecimiento de Agua , Microbiología del AguaRESUMEN
BACKGROUND: Tap water distrust and avoidance, indicators of water insecurity, are prevalent in marginalized United States populations. As future environmental challenges stress water resources, further understanding of the scope of water insecurity and its impact on diet quality is needed, particularly in vulnerable United States populations. OBJECTIVES: To evaluate associations between 3 potential indicators of water insecurity-1) perception of tap water safety for drinking, 2) perception of tap water safety for cooking, and 3) tap water avoidance-and dietary quality and beverage intake in lower-income United States adults. METHODS: A cross-sectional, web-based survey was fielded to 1798 lower-income (<250% federal poverty guidelines) United States adults. Participants answered questions detailing tap water safety perceptions and avoidance, beverage intake, dietary intake (30-d prime diet quality score), and sociodemographic covariates. Sociodemographic differences in drinking water insecurity measures were evaluated using chi-square and Fisher-Freeman-Halton tests. Associations between water insecurity measures and dietary outcomes were assessed using generalized linear models adjusted for sociodemographic covariates, and effect modification by sociodemographic covariates was assessed. RESULTS: Over half of the adults surveyed experienced some aspect of water insecurity. Measures of water security differed significantly by sociodemographic covariates (Ps < 0.05), with higher percentages of women and gender-nonconforming persons, minoritized racial and ethnic groups, lower-income groups, and food-insecure adults reporting indicators of water insecurity. Presence of any water insecurity was associated with lower diet quality (ß = -1.07; 95% CI: -2.11, -0.03; P = 0.04), lower tap water intake (relative difference [RD] = 0.35; 95% CI: 1.28, 2.12; P < 0.0001), higher bottled water intake (RD = 1.64; 95% CI: 1.28, 2.12; P = 0.0001), and higher sugar-sweetened beverages intake frequency (frequency ratio = 1.13; 95% CI: 1.01, 1.27; P = 0.03). CONCLUSIONS: Water insecurity indicators are associated with poorer diet quality and beverage intake in a population of United States adults with lower-incomes. Addressing the intersection of water insecurity, food security, environmental impacts, and nutrition may help to improve the well-being and resiliency of vulnerable populations.
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Agua Potable , Inseguridad Hídrica , Adulto , Humanos , Estados Unidos , Femenino , Estudios Transversales , Dieta , Bebidas , Pobreza , Encuestas NutricionalesRESUMEN
Urolithiasis is a highly prevalent global disease with substantially increasing incidence in the last two decades. Data from the literature suggests that 26%-50% of patients will have a recurrence within 10 years after an initial symptomatic stone episode. Therefore, interest has been raised in preventive strategies, aiming to modify the risk factors of stone recurrence by implementing dietary and lifestyle changes and specific medical treatments for stone formers, depending on their recurrence risk factors. Certain dietary factors are thought to contribute significantly to the increased incidence of urolithiasis, particularly a diet low in fiber and high in animal protein, fat, and sodium. Fluid intake is perhaps the most important and modifiable step in the prevention of urolithiasis, irrespective of stone composition. However, the amount of fluid to be consumed and the implications of various fluid types on stone formation are still controversial. In this article, the relationship between fluid intake, beverage types and stone formation-prevention will be discussed. Moreover, general dietary recommendations for patients without metabolic risk factors will be reviewed based on the current literature.
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Dieta , Ingestión de Líquidos , Urolitiasis , Humanos , Factores de Riesgo , Urolitiasis/etiología , Urolitiasis/prevención & control , Estilo de VidaRESUMEN
Phosphate dosing is the principle strategy used in the United Kingdom to reduce the concentration of lead in tap waters supplied by lead water pipes. The mechanisms of phosphate-mediated lead control are not fully understood, but solid solutions of lead calcium apatite are thought to play an important role. This study investigated the microstructure of a lead pipe, supplied with high-alkalinity tap water, in which the lead calcium apatite crystals were spherulitic having rounded and dumb-bell-shaped morphologies. XRD, Fourier transform infrared spectroscopy, optical microscopy, Raman spectroscopy, scanning electron microscopy, and energy-dispersive spectroscopy showed that the lead pipe had a well-established inner layer of litharge; a middle layer containing lead calcium apatite spherulites, plumbonacrite, and some hydrocerussite; and an outer layer containing iron, lead, phosphorus, calcium, silicon, and aluminum. It was found that spherulitic lead calcium apatite could be grown in the laboratory by adding hydrocerussite to synthetic soft and hard water-containing phosphate, chloride, and citrate ions at pH 5.5 but not when the citrate was absent. This suggests that dissolved organic molecules might play a role in spherulite formation on lead water pipes. These molecules might inhibit the formation of lead calcium apatite, reducing the effectiveness of phosphate dosing in lead water pipes.
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Apatitas , Fumar en Pipa de Agua , Apatitas/química , Calcio , Fosfatos/química , Concentración de Iones de Hidrógeno , Microscopía Electrónica de Rastreo , Citratos , Espectroscopía Infrarroja por Transformada de Fourier , Fosfatos de Calcio/químicaRESUMEN
High resolution mass spectrometry (HRMS) coupled to either gas chromatography or reversed-phase liquid chromatography is the generic method to identify unknown disinfection byproducts (DBPs) but can easily overlook their highly polar fractions. In this study, we applied an alternative chromatographic separation method, supercritical fluid chromatography-HRMS, to characterize DBPs in disinfected water. In total, 15 DBPs were tentatively identified for the first time as haloacetonitrilesulfonic acids, haloacetamidesulfonic acids, and haloacetaldehydesulfonic acids. Cysteine, glutathione, and p-phenolsulfonic acid were found as precursors during lab-scale chlorination, with cysteine providing the highest yield. A mixture of the labeled analogues of these DBPs was prepared by chlorination of 13C3-15N-cysteine and analyzed using nuclear magnetic resonance spectroscopy for structural confirmation and quantification. A total of 6 drinking water treatment plants utilizing various source waters and treatment trains produced sulfonated DBPs upon disinfection. Those were widespread in the tap water of 8 cities across Europe, with estimated concentrations up to 50 and 800 ng/L for total haloacetonitrilesulfonic acids and haloacetaldehydesulfonic acids, respectively. Up to 850 ng/L haloacetonitrilesulfonic acids were found in 3 public swimming pools. Considering the stronger toxicity of haloacetonitriles, haloacetamides, and haloacetaldehydes than the regulated DBPs, these newly found sulfonic acid derivatives may also pose a health risk.
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Cromatografía con Fluido Supercrítico , Desinfectantes , Agua Potable , Contaminantes Químicos del Agua , Purificación del Agua , Desinfección/métodos , Desinfectantes/análisis , Desinfectantes/química , Agua Potable/análisis , Ácidos Sulfónicos/análisis , Cisteína/análisis , Contaminantes Químicos del Agua/análisis , Espectrometría de Masas , HalogenaciónRESUMEN
Trichloroacetic acid is known as one of the harmful disinfection byproducts with chlorine of tap water and is regulated according to legally binding standards in Japanese Drinking Water Quality Standards. We developed a high-purity trichloroacetic acid reference material, NMIJ CRM 4074-a, with certified purity as a traceability source of standard solution supplied under the Japan Calibration Service System (JCSS). As trichloroacetic acid is hygroscopic, water could be the main impurity. Although all impurities in the sample can be possibly detected by the freezing point depression method (FPD), it was unclear for trichloroacetic acid whether water was detected by FPD owing to evaporation of water from the sample during fusion. Therefore, we confirmed that water in trichloroacetic acid was detected as an impurity by FPD. The procedure was validated from an increment of purity by FPD due to reduction of water content and an agreement of purity by FPD with those by neutralization titrimetry (NT) and mass balance approach (MBA), both methods were based on different measurement principles from FPD. The certified value was determined to be (0.999 ± 0.003) kg kg-1 from the purity assay by FPD and NT, and uncertainties due to the homogeneity and stability of the CRM were included in the expanded uncertainty. The reliability of the certified value was verified by the agreement of purities by FPD, NT, and MBA.
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Contaminated drinking water (DW) is a major source of exposure to per- and polyfluoroalkyl substances (PFAS) at locations around PFAS production/use facilities and military airports. This study aimed to investigate quantitative relationships between concentrations in DW and serum of nine perfluoroalkyl acids (PFAAs) in Swedish adult populations living near contamination hotspots. Short-chained (PFPeA, PFHxA, PFHpA, and PFBS) and long-chained PFAAs (PFOA, PFNA, PFDA, PFHxS and PFOS) were measured in DW and serum. We matched DW and serum concentrations for a total of 398 subjects living or working in areas receiving contaminated DW and in one non-contaminated area. Thereafter, linear regression analysis with and without adjustments for co-variates was conducted. This enabled to derive (i) serum concentrations at background exposure (CB) from sources other than local DW exposure (i.e. food, dust and textiles) at 0 ng/L DW concentration, (ii) population-mean PFAA serum:water ratios (SWR) and (iii) PFAA concentrations in DW causing observable elevated serum PFAA concentrations above background variability. Median concentrations of the sum of nine PFAAs ranged between 2.8 and 1790 ng/L in DW and between 7.6 and 96.9 ng/mL in serum. DW concentration was the strongest predictor, resulting in similar unadjusted and adjusted regression coefficients. Mean CB ranged from <0.1 (PFPeA, PFHpA, PFBS) to 5.1 ng/mL (PFOS). Serum concentrations increased significantly with increasing DW concentrations for all PFAAs except for PFPeA with SWRs ranging from <10 (PFHxA, PFHpA and PFBS) to 111 (PFHxS). Observed elevated serum concentrations above background variability were reached at DW concentrations between 24 (PFOA) and 357 ng/L (PFHxA). The unadjusted linear regression predictions agreed well with serum concentrations previously reported in various populations exposed to low and high DW levels of PFOA, PFHxS and PFOS. The quantitative relationships derived herein should be helpful to translate PFAA concentrations in DW to concentrations in serum at the population level.