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1.
J Korean Med Sci ; 2020 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-32924345

RESUMO

The advent of the global pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) necessitates a thorough study of the stability and transmissibility in the environment. We characterized the stability of SARS-CoV-2 in three water matrices: fresh, tap, and seawater. The minimum infective dose of SARS-CoV-2 in Vero cells was confirmed to be 10³ PFU/mL. The stability of SARS-CoV-2 varied according to the water matrix: infective SARS-CoV-2 was undetectable after treatment with fresh water and seawater, but remained detectable for 2 days in tap water, when starting with an initial concentration of 104 PFU/mL. When the starting concentration was increased to 105 PFU/mL, a similar trend was observed. In addition, viral RNA persisted longer than infectious virus in all water matrices. This study was conducted in stagnant water containing a significantly high titer of virus, thus, human-to-human transmission of SARS-CoV-2 through the actual aquatic environment is expected to be rare.


Assuntos
Betacoronavirus/isolamento & purificação , Infecções por Coronavirus/virologia , Água Potável/virologia , Água Doce/virologia , Pneumonia Viral/virologia , Água do Mar/virologia , Microbiologia da Água , Abastecimento de Água , Animais , Betacoronavirus/fisiologia , Chlorocebus aethiops , Infecções por Coronavirus/transmissão , Pandemias , Pneumonia Viral/transmissão , Células Vero , Carga Viral , Cultura de Vírus , Inativação de Vírus
2.
Chemosphere ; 254: 126890, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957290

RESUMO

Chlorine disinfection inactivates pathogens in drinking water, but meanwhile it causes the formation of halogenated disinfection byproducts (DBPs), which may induce adverse health effects. Humans are unavoidably exposed to halogenated DBPs via tap water ingestion. Boiling of tap water has been found to significantly reduce the concentrations of halogenated DBPs. In this study, we found that compared with boiling only, adding ascorbate (vitamin C) or carbonate (baking soda) to tap water and then boiling the water further reduced the level of total organic halogen (a collective parameter for all halogenated DBPs) by up to 36% or 28%, respectively. Adding ascorbate removed the chlorine residual in tap water and thus prevented the formation of more halogenated DBPs in the boiling process. Adding carbonate elevated pH of tap water and consequently enhanced the hydrolysis (dehalogenation) of halogenated DBPs or led to the formation of more trihalomethanes that might volatilize to air during the boiling process. The comparative developmental toxicity of the DBP mixtures in the water samples was also evaluated. The results showed that adding a tiny amount of sodium ascorbate or carbonate (2.5-5.0 mg/L) to tap water followed by boiling for 5 min reduced the developmental toxicity of tap water to a substantially lower level than boiling only. The addition of sodium ascorbate or carbonate to tap water in household could be realized by preparing them in tiny pills. This study suggests simple and effective methods to reduce the adverse effects of halogenated DBPs on humans through tap water ingestion.


Assuntos
Desinfetantes/toxicidade , Poluentes Químicos da Água/toxicidade , Ácido Ascórbico , Carbonatos , Cloro , Desinfetantes/análise , Desinfecção/métodos , Água Potável/química , Halogenação , Halogênios , Humanos , Trialometanos/análise , Volatilização , Poluentes Químicos da Água/análise , Purificação da Água/métodos
3.
Wei Sheng Yan Jiu ; 49(4): 540-545, 2020 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-32928345

RESUMO

OBJECTIVE: To understand the rural sanitary conditions in different geographical areas of Shaanxi Province. METHODS: According to the stratified random sampling method, 30 agriculture-related counties were selected(The central area includes 13 counties in Xi'an, Tongchuan, Weinan, Xianyang and Baoji cities. The southern area includes 10 counties in Hanzhong, Ankang, Shangluo cities. The northern area includes 7 counties in Yulin, Yan'an cities. ). Five townships were selected randomly in each county(excluding Chengguan Town), and 4 administrative villages were selected randomly in each township as survey villages, which were collected the soil samples for testing lead, cadmium and chromium in each subject village, and 5 households were randomly selected in each villages as survey households. The data was obtained through data reading, interviews, on-site observations, and laboratory testing, etc. The detection of soil lead and cadmium was carried out according to the Measurement of Soil Quality Lead and Cadmium by Graphite Furnace Atomic Absorption Spectrophotometry(GB/T 17141-1997), and the detection of chromium was carried out according to the Determination of Total Chromium in Soil by Flame Atomic Absorption Spectrometry(HJ 491). The data was statistically analyzed and evaluated according to the central, southern and northern regions. RESULTS: The population coverage of rural centralized water supply in the three regions(central、southern and northern area) was 92. 86%, 75. 49% and 70. 41%, respectively. The penetration rate of sanitary toilets was 28. 18%, 45. 38% and 9. 90%, respectively. The proportion of villages where domestic garbage was randomly stacked was 0. 38%, 4. 00% and 32. 86%, respectively. The proportion of villages where domestic sewage was randomly discharged was 30. 38%, 40. 00% and 60. 00%, respectively. The heavy metals exceeding the standard in the soil were mainly cadmium. The over-standard rates were 4. 62%, 21. 50% and 0. 71%, respectively. The three regional differences of the above result were statistically significant(χ~2=57 676. 74, 18 143. 94, 124. 86, 33. 15 and 54. 12, P<0. 01). CONCLUSION: There was still some decentralized water supply population in the province. The coverage rate of the centralized water supply population and the proportion of drinking water after complete treatment projects were both higher in the central area than in the southern area and northern area. Sanitation toilets have a low penetration rate in the province, which was higher in the southern area than in the central area and the northern area. The domestic garbage was randomly discarded, and domestic sewage was randomly discharged, which was more in the northern area than in the central area and the southern area. Soil cadmium pollution was relatively heavy, mainly in the southern area.


Assuntos
Água Potável , Metais Pesados , Cidades , Humanos , Saneamento , Abastecimento de Água
4.
Wei Sheng Yan Jiu ; 49(4): 619-623, 2020 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-32928358

RESUMO

OBJECTIVE: To evaluate the capacity of national laboratories for determination of bromate in drinking water using Proficiency Testing Program. METHODS: The preparation method of the Secondary Standard Materials were used as the reference for the sample preparation in this Proficiency Testing Program. The homogeneity and stability of the samples and short-term stability for simulated transportation were tested by Single Factor Analysis of Variance(ANOVA) and Linear Regression and Mean consistency test. The result provided by participant laboratories were analyzed by robust statistics and assessed using the Z-score. RESULTS: A total of 369 laboratories throughout the country participated in the Proficiency Testing Program. 341 laboratories, or 92. 4% of total participating laboratories, obtained satisfactory result. Results provided by 8 laboratories, or 2. 2% of total participating laboratories, were found to suggest doubts in their capacities. Finally, there were 20 laboratories, constituting 5. 4% of total participating laboratories, with result that were found to be outliers. CONCLUSION: The capacity of national laboratories for determination of bromate in drinking water has been ranked as satisfactory according to statistical analysis of the Proficiency Testing Program result. Only a small portion of the participants require further improvement in their capacities.


Assuntos
Água Potável/análise , Bromatos , Humanos , Laboratórios , Ensaio de Proficiência Laboratorial
5.
Wei Sheng Yan Jiu ; 49(4): 624-629, 2020 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-32928359

RESUMO

OBJECTIVE: To evaluate the capacity of national laboratories for determination of iron in drinking water using Proficiency Testing Program. METHODS: The preparation method of the Secondary Standard Materials were used as the reference for the sample preparation in this Proficiency Testing Program. The homogeneity and stability of the samples and short-term stability for simulated transportation were tested by Single Factor Analysis of Variance(ANOVA) and Linear Regression and Mean consistency test. The result provided by participant laboratories were analyzed by robust statistics and assessed using the Z-score. RESULTS: A total of 1010 laboratories throughout the country participated in the Proficiency Testing Program. 928 laboratories, or 91. 9% of total participating laboratories, obtained satisfactory result. Results provided by 19 laboratories, or 1. 9% of total participating laboratories, were found to suggest doubts in their capacities. Finally, there were 63 laboratories, constituting 6. 2% of total participating laboratories, with result that were found to be outliers. CONCLUSION: The capacity of national laboratories for determination of iron in drinking water has been ranked as satisfactory according to statistical analysis of the Proficiency Testing Program result. Only a small portion of the participants require further improvement in their capacities.


Assuntos
Água Potável/análise , Humanos , Ferro , Laboratórios , Ensaio de Proficiência Laboratorial
6.
Wei Sheng Yan Jiu ; 49(4): 630-634, 2020 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-32928360

RESUMO

OBJECTIVE: To evaluate the capacity of national laboratories for determination of chlorate in drinking water using Proficiency Testing Program. METHODS: The preparation method of the Secondary Standard Materials were used as the reference for the sample preparation in this Proficiency Testing Program. The homogeneity and stability of the samples and short-term stability for simulated transportation were tested by Single Factor Analysis of Variance(ANOVA) and Linear Regression and Mean consistency test. The result provided by participant laboratories were analyzed by robust statistics and assessed using the Z-score. RESULTS: A total of 327 laboratories throughout the country participated in the Proficiency Testing Program. 307 laboratories, or 93. 9% of total participating laboratories, obtained satisfactory result. Results provided by 5 laboratories, or 1. 5% of total participating laboratories, were found to suggest doubts in their capacities. Finally, there were 15 laboratories, constituting 4. 6% of total participating laboratories, with result that were found to be outliers. CONCLUSION: The capacity of national laboratories for determination of chlorate in drinking water has been ranked as satisfactory according to statistical analysis of the Proficiency Testing Program result. Only a small portion of the participants require further improvement in their capacities.


Assuntos
Água Potável/análise , Cloratos , Humanos , Laboratórios , Ensaio de Proficiência Laboratorial
7.
Wei Sheng Yan Jiu ; 49(4): 635-639, 2020 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-32928361

RESUMO

OBJECTIVE: To evaluate the capacity of national laboratories for determination of anion synthetic detergent in drinking water using Proficiency Testing Program. METHODS: The preparation method of the Secondary Standard Materials were used as the reference for the sample preparation in this Proficiency Testing Program. The homogeneity and stability of the samples and short-term stability for simulated transportation were tested by Single Factor Analysis of Variance(ANOVA) and Linear Regression and Mean consistency test. The result provided by participant laboratories were analyzed by robust statistics and assessed using the Z-score. RESULTS: A total of 723 laboratories throughout the country participated in the Proficiency Testing Program. 668 laboratories, or 92. 4% of total participating laboratories, obtained satisfactory result. Results provided by 15 laboratories, or 2. 1% of total participating laboratories, were found to suggest doubts in their capacities. Finally, there were 40 laboratories, constituting 5. 5% of total participating laboratories, with result that were found to be outliers. CONCLUSION: The capacity of national laboratories for determination of anion synthetic detergent in drinking water has been ranked as satisfactory according to statistical analysis of the Proficiency Testing Program result. Only a small portion of the participants require further improvement in their capacities.


Assuntos
Água Potável/análise , Detergentes , Humanos , Laboratórios , Ensaio de Proficiência Laboratorial
8.
Environ Monit Assess ; 192(10): 641, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32929589

RESUMO

Monitoring the groundwater quality situation and identifying the various pollution loads' sources are a prerequisites to finding solutions. In many areas, nitrate and salinity are one of the prime pollutants in the groundwater. This investigation is carried to present the results of a monitoring study focusing on 20 wells samples collected from the shallow groundwater of Guenniche plain (North Tunisia) during the wet season of May 2016, to present its suitability for drinking purposes with emphasis on the assessment of the presence of nitrate and salinity elements. Nitrate levels' results show that 55% of the samples exceeded the National Tunisian standard limit (NT) and the World Health Organization standard limit (WHO). The salinity results, measured as total dissolved solids (TDS), show that 95% of the samples exceed the international standard, and 25% exceed the national standard. A total of 20% of the wells exceeded the nitrite standards. The total hardness levels indicate that 90% of the samples present very hard water. The Guenniche shallow groundwater average concentrations are categorized as follows: Na+ > Ca2+ > Mg2+ > K+ for the cations and Cl- > SO42- > HCO3- > NO3- for the anions. Nitrate and salinity variations during the period 2006-2015 follow the rainfall fluctuation patterns. The assessment of water quality using Water Quality Index revealed that 95% of the wells' water classes ranged between "poor", "very poor," and "unsuitable for drinking purposes". Therefore, these wells are affected by anthropogenic and/or natural factors and they are inadvisable for drinking purposes, unless the water from these wells undergoes appropriate treatment before use.


Assuntos
Água Potável , Água Subterrânea , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Salinidade , Tunísia , Qualidade da Água
9.
PLoS Med ; 17(9): e1003245, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32898152

RESUMO

BACKGROUND: Beverages, especially sugar-sweetened beverages (SSBs), have been increasingly subject to policies aimed at reducing their consumption as part of measures to tackle obesity. However, precision targeting of policies is difficult as information on what types of consumers they might affect, and to what degree, is missing. We fill this gap by creating a typology of beverage consumers in Great Britain (GB) based on observed beverage purchasing behaviour to determine what distinct types of beverage consumers exist, and what their socio-demographic (household) characteristics, dietary behaviours, and weight status are. METHODS AND FINDINGS: We used cross-sectional latent class analysis to characterise patterns of beverage purchases. We used data from the 2016 GB Kantar Fast-Moving Consumer Goods (FMCG) panel, a large representative household purchase panel of food and beverages brought home, and restricted our analyses to consumers who purchase beverages regularly (i.e., >52 l per household member annually) (n = 8,675). Six categories of beverages were used to classify households into latent classes: SSBs; diet beverages; fruit juices and milk-based beverages; beer and cider; wine; and bottled water. Multinomial logistic regression and linear regression were used to relate class membership to household characteristics, self-reported weight status, and other dietary behaviours, derived from GB Kantar FMCG. Seven latent classes were identified, characterised primarily by higher purchases of 1 or 2 categories of beverages: 'SSB' (18% of the sample; median SSB volume = 49.4 l/household member/year; median diet beverage volume = 38.0 l), 'Diet' (16%; median diet beverage volume = 94.4 l), 'Fruit & Milk' (6%; median fruit juice/milk-based beverage volume = 30.0 l), 'Beer & Cider' (7%; median beer and cider volume = 36.3 l; median diet beverage volume = 55.6 l), 'Wine' (18%; median wine volume = 25.5 l; median diet beverage volume = 34.3 l), 'Water' (4%; median water volume = 46.9 l), and 'Diverse' (30%; diversity of purchases, including median SSB volume = 22.4 l). Income was positively associated with being classified in the Diverse class, whereas low social grade was more likely for households in the classes SSB, Diet, and Beer & Cider. Obesity (BMI > 30 kg/m2) was more prevalent in the class Diet (41.2%, 95% CI 37.7%-44.7%) despite households obtaining little energy from beverages in that class (17.9 kcal/household member/day, 95% CI 16.2-19.7). Overweight/obesity (BMI > 25 kg/m2) was above average in the class SSB (66.8%, 95% CI 63.7%-69.9%). When looking at all groceries, households from the class SSB had higher total energy purchases (1,943.6 kcal/household member/day, 95% CI 1,901.7-1,985.6), a smaller proportion of energy from fruits and vegetables (6.0%, 95% CI 5.8%-6.3%), and a greater proportion of energy from less healthy food and beverages (54.6%, 95% CI 54.0%-55.1%) than other classes. A greater proportion of energy from sweet snacks was observed for households in the classes SSB (18.5%, 95% CI 18.1%-19.0%) and Diet (18.8%, 95% CI 18.3%-19.3%). The main limitation of our analyses, in common with other studies, is that our data do not include information on food and beverage purchases that are consumed outside the home. CONCLUSIONS: Amongst households that regularly purchase beverages, those that mainly purchased high volumes of SSBs or diet beverages were at greater risk of obesity and tended to purchase less healthy foods, including a high proportion of energy from sweet snacks. These households might additionally benefit from policies targeting unhealthy foods, such as sweet snacks, as a way of reducing excess energy intake.


Assuntos
Bebidas/economia , Comércio/tendências , Comportamento do Consumidor/economia , Adulto , Animais , Bebidas Adoçadas Artificialmente , Cerveja , Peso Corporal , Comportamento do Consumidor/estatística & dados numéricos , Estudos Transversais , Água Potável , Características da Família , Feminino , Sucos de Frutas e Vegetais , Humanos , Renda , Análise de Classes Latentes , Masculino , Leite , Inquéritos Nutricionais , Obesidade/psicologia , Reino Unido , Vinho
10.
Ecotoxicol Environ Saf ; 203: 110984, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888605

RESUMO

The use of water for drinking and agriculture requires knowledge of its toxicity. In this study, we compared the use of genetically modified bioluminescent (GMB) bacteria whose luminescence increases in the presence of toxicants and Chinese Hamster Ovary (CHO) cells for the characterization of the toxicity of water samples collected from a lake and streams, hydroponic and aquaponic farms, and a wastewater treatment plant. GMB bacteria were used to probe genotoxicity, cytotoxicity and reactive oxygen species-induced effects in the whole water samples. Unlike GMB bacteria, the use of CHO cells requires XAD resin-based pre-concentration of toxic material present in water samples for the subsequent cytotoxicity assay. In addition to the examination of the toxicity of the water from the different sources, the GMB bacteria were also used to test the XAD extracts diluted to the concentrations causing 50% growth inhibition of the CHO cells. The two biomonitoring tools provided different results when they were used to test the above-mentioned diluted XAD extracts. A pre-concentration procedure based on adsorption by XAD resins with subsequent elution was not sufficient to represent the material responsible for the toxicity of the whole water samples toward the GMB bacteria. Therefore, the use of XAD resin extracts may lead to major underestimates of the toxicity of water samples. Although the toxicity findings obtained using the GMB bacteria and CHO cells may not correlate with each another, the GMB bacteria assay did provide a mechanism-specific biomonitoring tool to probe the toxicity of water samples without a need for the pre-concentration step.


Assuntos
Bactérias , Monitoramento Biológico/métodos , Água Potável/análise , Lagos/análise , Rios , Águas Residuárias/análise , Animais , Bactérias/genética , Células CHO , Cricetulus , Hidroponia , Luminescência , Microrganismos Geneticamente Modificados/genética , Eliminação de Resíduos Líquidos
11.
Chemosphere ; 258: 127387, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32947680

RESUMO

It is well known that serum is an ideal and potential choice to reflect the toxicity of fluoride. However, the effects of fluoride on serum metabolome have not been reported until now. In this study, the models of 3-week-old rats exposed fluoride by breast milk and 11-week-old rats exposed fluoride via breast milk and drinking water containing sodium fluoride (100 mg/L) were established. Using Ultra Performance Liquid Chromatography-Mass Spectrometry/Mass Spectrometry (UPLC-MS/MS), as compared with control group, 28 negative (NEG) and 52 positive (POS) metabolites were significantly up-regulated, meanwhile 30 NEG and 21 POS significantly down-regulated metabolites were found in serum of 3-week-old rats exposed to fluoride. For 11-week-old fluorosis rats, there were 119 NEG and 65 POS metabolites significantly increased, and 7 NEG, 5 POS metabolites were obviously decreased. Importantly, nicotinamide, adenosine, 1-Oleoyl-sn-glycero-3-phosphocholine (OGPC), and 1-Stearoyl-sn-glycerol 3-phosphocholine (SGPC) were shared by two models. The metabolites of urea cycle, such as urea and N2-Acetyl-l-ornithine, betaine as a methyl donor, were regarded to reflect the fluorosis degree. These metabolites could be the potential markers of fluorosis, contributing to the prevention and treatment of fluorosis.


Assuntos
Fluoretos/toxicidade , Metaboloma/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Animais , Betaína , Cromatografia Líquida , Água Potável/química , Feminino , Humanos , Masculino , Metabolômica , Leite/metabolismo , Ratos , Fluoreto de Sódio , Espectrometria de Massas em Tandem
12.
Sci Total Environ ; 738: 140382, 2020 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-32806349

RESUMO

Approximately 1.5 million individuals in Ontario are supplied by private water wells (private groundwater supplies). Unlike municipal supplies, private well water quality remains unregulated, with owners responsible for testing, treating, and maintaining their own water supplies. The primary goal of this study was to assess the effect of repeat sampling of private well water in Ontario and investigate the efficacy of geographically- and/or temporally specific testing recommendations and health risk assessments. The current study combines the Well Water Information System Dataset and the Well Water Testing Dataset from 2010 to 2017, inclusive. These two large existing province-wide datasets collated over an eight-year period were merged using an integrated spatial fuzzy logic and (next)- nearest neighbour approach. Provincial sampling data from 239,244 wells (702,861 samples) were analyzed for Escherichia coli to study the relationship between sampling frequency and Escherichia coli detection. Dataset variables were delineated based on hydrogeological setting (e.g. aquifer type, overburden depth, well depth, bedrock type) and seasonality to provide an in-depth understanding of Escherichia coli detection in private well water. Findings reveal differences between detection rates in consolidated and unconsolidated aquifers (p = 0.0191), and across seasons (p < 0.0001). The variability associated with Escherichia coli detection rates was explored by estimating sentinel sampling rates for private wells sampled three times, twelve times and twenty-four times per year. As sample size increases on an annual basis, so too does detection rate, highlighting the need to address current testing frequency guidelines. Future health risk assessments for private well water should consider the impact of spatial and temporal factors on the susceptibility of this drinking water source, leading to an increasingly accurate depiction of private well water contamination and the estimated effects on human health.


Assuntos
Água Potável , Água Subterrânea , Humanos , Ontário , Medição de Risco , Poços de Água
13.
Sci Total Environ ; 737: 140296, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32783866

RESUMO

Disinfection byproducts (DBPs) in drinking water is an issue in many countries. Many DBPs are possible or probable human carcinogens while few DBPs pose cyto- and genotoxic effects to the mammalian cells. The populations are likely to consume DBPs with drinking water throughout their lifetimes. A number of DBPs are regulated in many countries to protect humans. In this study, human exposure, risk and disability-adjusted life years (DALY) were predicted from DBPs in multiple water supply systems, including groundwater (GW), desalinated water (DW) and blend water (BW). The averages of lifetime excess cancer risks from GW, DW and BW were 4.15 × 10-6, 1.75 × 10-5 and 2.59 × 10-5 respectively. The populations in age groups of 0 - <2, 2-16 and >16 years contributed 25.4-25.7%, 28.6-29.6% and 45.0-45.7% to the total risks respectively. The DALY from GW, DW and BW were estimated to be 5.8, 27.0 and 39.9 years, respectively while the corresponding financial burdens were US$ 0.63, 2.93 and 4.34 million respectively. The findings are likely to assist in selecting the supply water sources to better control human exposure and risk from DBPs.


Assuntos
Desinfetantes/análise , Água Potável/análise , Poluentes Químicos da Água/análise , Purificação da Água , Animais , Desinfecção , Halogenação , Humanos , Anos de Vida Ajustados por Qualidade de Vida , Arábia Saudita , Abastecimento de Água
14.
J Environ Sci (China) ; 96: 151-162, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32819689

RESUMO

Within the drinking water distribution system (DWDS) using chloramine as disinfectant, nitrification caused by nitrifying bacteria is increasingly becoming a concern as it poses a great challenge for maintaining water quality. To investigate efficient control strategies, operational conditions including hydraulic regimes and disinfectant scenarios were controlled within a flow cell experimental facility. Two test phases were conducted to investigate the effects on the extent of nitrification of three flow rates (Q = 2, 6, and 10 L/min) and four disinfection scenarios (total Cl2=1 mg/L, Cl2/NH3-N=3:1; total Cl2=1 mg/L, Cl2/NH3-N=5:1; total Cl2=5 mg/L, Cl2/NH3-N=3:1; and total Cl2=5 mg/L, Cl2/NH3-N=5:1). Physico-chemical parameters and nitrification indicators were monitored during the tests. The characteristics of biofilm extracellular polymetric substance (EPS) were evaluated after the experiment. The main results from the study indicate that nitrification is affected by hydraulic conditions and the process tends to be severe when the fluid flow transforms from laminar to turbulent (2300

Assuntos
Desinfetantes , Água Potável , Biofilmes , Desinfecção , Nitrificação
15.
Chimia (Aarau) ; 74(7): 524-537, 2020 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-32778205

RESUMO

Groundwater is a much safer and more dependable source of drinking water than surface water. However, natural (geogenic) hazardous elements can contaminate groundwater and lead to severe health problems in consumers. Arsenic concentrations exceeding the WHO drinking water guideline of 10 µg/L globally affect over 220 million people and can cause arsenicosis (skin lesions and cancers). Fluoride, while preventing caries at low concentrations, has detrimental effects when above the WHO drinking water guideline of 1.5 mg/L and puts several hundred million people at risk of dental and skeletal fluorosis. In this article, we report on the geochemistry and occurrence of arsenic and fluoride in groundwater and on the development of global and regional risk maps that help alert governments and water providers to take appropriate mitigation measures for the provision of safe drinking water. We then summarize research on the removal of arsenic and fluoride from drinking water, focusing on adapted technologies for water treatment. Finally, we discuss the applicability of various measures in a larger context and future challenges in reaching the goal of access to safe drinking water for all.


Assuntos
Água Subterrânea , Arsênico , Água Potável , Monitoramento Ambiental , Fluoretos , Poluentes Químicos da Água
16.
J Environ Manage ; 274: 111202, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32784082

RESUMO

In this research, multivariate statistical analysis was performed on twenty water quality parameters (WQP) collected on tri-monthly basis (four times/year) from 441 drinking water sources in Newfoundland and Labrador (NL), Canada for 18 years (1999-2016). The WQP included alkalinity (Alk), color (Col), conductivity (Cond), hardness (Hard), pH, total dissolved solids (TDS), turbidity (Turb), bromide (Br), calcium (Ca), chloride (Cl), fluoride (F), potassium (K), sodium (Na), sulfate (SO4), dissolved organic carbon (DOC), ammonia (NH3), nitrate (NO3), Kjeldahl nitrogen (N), total phosphorus (P) and magnesium (Mg). The assessment was conducted on surface water (SWS) and groundwater (GWS) sources separately. In SWS and GWS, number of samples analyzed for each WQP were in the ranges of 3434-6057 and 1915-1919 respectively. Averages of DOC and pH showed increasing trends (SWS: DOC = 0.0722 mg/L/year; pH = 0.0375 units/year; GWS: DOC = 0.0491 mg/L/year; pH = 0.0441 units/year) while the other WQP showed variable characteristics, which could increase treatment cost and deteriorate tap water quality. Strong correlations were observed for Ca-Hard (r = 0.97-0.98), TDS-Cond (r = 0.91-0.99) and Na-Cl (r = 0.87-0.96). In SWS, Alk had stronger correlations with Cond, Hard, pH, TDS, Ca and Mg (r = 0.62-0.94) than GWS (r = 0.56-0.63). Principal Component Analysis revealed separate clusters for DOC-Col, Na-Cl, TDS-Cond, Ca-Alk and Mg-Hard, indicating that these WQP moved together. In SWS and GWS, six principal components were significant (eigenvalue ≥ 1.0), and explained 74.8% and 72.9% of overall variances respectively. In Factor Analysis, six varifactors explained 73.4% and 70.5% of total variances in SWS and GWS respectively. For SWS and GWS, eleven and ten WQP, respectively explained these variances, indicating 45% and 50% data reduction respectively. The findings can assist in controlling water quality through monitoring reduced number of WQP, which is likely to minimize the monitoring cost.


Assuntos
Água Potável/análise , Água Subterrânea , Poluentes Químicos da Água/análise , Canadá , Monitoramento Ambiental , Análise Multivariada , Terra Nova e Labrador , Qualidade da Água , Abastecimento de Água
17.
Wiad Lek ; 73(4): 796-800, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32731720

RESUMO

OBJECTIVE: The aim: To study health status among the children in connection with a prolonged exposure of drinking water from decentralized systems. PATIENTS AND METHODS: Materials and methods: The prevalence rates of diseases among children of rural areas were studied according to the statistical reports in Dnipropetrovsk region healthinformation center from 2008 to 2013 using statistical form № 12 (totally 220 reports). The distribution of rural areas in the region was based on the cluster analysis. The horizontal dendrogram showing similarity between the research areas in a multidimensional space. Cluster analysis includes 2 groups of rural districts in Dnipropetrovsk region. RESULTS: Results: It is established that with increase of pH#62; 7.5-7.6 in water of decentralized systems decreased the prevalence in the majority of nosologies: diseases of the blood and hematopoietic organs (rS=0,331; p#60;0,001), musculoskeletal system (rS=-0,174; p#60;0,001), anemia (rS=-0,331; p#60;0,001), congenital anomalies (rS=-0,272; p=0,002) among children population. CONCLUSION: Conclusions: Among those children, who consumed drinking water from wells with content of some essential trace elements on the limits of MPC: 71% did not suffer from chronic diseases of the circulatory system (Fe >0.144 mg/dm3); 59% did not suffer from the diseases of digestive system (Cu #62;0.089 mg/dm3), and 60% had no congenital abnormalities of circulatory system (Mn #62; 0.099 mg/dm3).


Assuntos
Água Potável , Nível de Saúde , Criança , Humanos , Prevalência , População Rural , Oligoelementos
18.
Environ Monit Assess ; 192(8): 558, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32740690

RESUMO

The objective of this study is to propose and apply a novel approach to develop a drinking water quality index that enables water managers to routinely identify the vulnerabilities in a distribution system (DS) while taking into account the priorities of water managers and operators. Here, we propose an innovative approach based on the participation of eight researchers and water managers. The input from these participants was included through a combination of the Delphi and MACBETH (Measuring Attractiveness by a Categorical-Based Evaluation Technique) methods, which were applied to an index developed using fuzzy logic. The index was then validated by conducting sensitivity and comparative analyses on a database from field sampling campaigns conducted in various small municipal DSs in two Canadian provinces: Quebec and Newfoundland and Labrador. Finally, the drinking water quality index was applied to a database of the DS in Quebec City, Canada. Sensitivity and comparative analyses revealed that the developed index could allow for the characterization of water sample quality and could prove useful for prioritizing interventions in the DS. The index was also useful for representing the spatial variability of water quality, and provided nuanced information about water quality, especially when the water quality parameter values complied with guidelines and regulations. These results provide a transferable and integrated approach for developing customized drinking water quality indices. This study will help pave the way for water quality managers to better prevent episodes of possible water quality deterioration.


Assuntos
Água Potável , Qualidade da Água , Canadá , Monitoramento Ambiental , Terra Nova e Labrador , Quebeque , Abastecimento de Água
19.
J Environ Manage ; 272: 111085, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32854889

RESUMO

Powdered activated carbon blocks (PACBs) are waste products obtained from household drinking water purification systems. In this study, we demonstrate that they can be used as adsorbents for the cost-effective and environmentally benign removal of hexavalent chromium (Cr(VI)) from contaminated-water and rinse electroplating wastewater. To evaluate Cr(VI) sorption onto the PACB, studies on equilibrium, kinetics, and thermodynamics were performed using batch mode experiments. The experimental results indicated that Cr(VI) ions were efficiently adsorbed under acidic conditions (i.e., at initial pH below 3) and low initial Cr(VI) concentrations. The adsorptive behaviors of the PACB for Cr(VI) were well explained by the Langmuir isotherm, as well as pseudo-second-order kinetic models, suggesting that a Cr(VI) monolayer was adsorbed onto the PACB surface via chemisorption. The maximum adsorption capacity of Cr(VI) onto the PACB was determined to be 6.207 mg/g. The results of thermodynamic studies revealed that the adsorption process of Cr(VI) onto PACB was endothermic and non-spontaneous. Additionally, analysis of the PACB after Cr(VI) adsorption at an initial pH of 2 using scanning electron microscopy, energy dispersive spectrometry, Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) revealed that the interaction between the surface oxygenic functional groups on the PACB and Cr(VI) was primarily responsible for Cr(VI) sorption via surface complexation and electrostatic interactions. Based on the result of XPS analysis, the presence of trivalent chromium on the PACB surfaces indicated that some synergistic redox reactions involving Cr(VI) could have occurred during the sorption process. Although a commercially available powdered activated carbon outperformed the PACB adsorbent with respect to Cr(VI) removal from wastewater, complete Cr(VI) adsorption could be achieved using relatively large quantities of the PACB. These findings indicate that the PACB adsorbent could be used as a cheap and efficient material for the removal of Cr(VI) from wastewater.


Assuntos
Água Potável , Poluentes Químicos da Água/análise , Purificação da Água , Adsorção , Carvão Vegetal , Cromo/análise , Concentração de Íons de Hidrogênio , Cinética
20.
Sci Total Environ ; 744: 140674, 2020 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-32755770

RESUMO

Faecally-contaminated drinking water is a risk to human health, with the greatest risks to those living in developing countries. UN Sustainable Development Goal 6 aims to address this issue. Tryptophan-like fluorescence (TLF) shows potential as a rapid method for detecting microbial contamination in drinking water, which could reduce the spread of waterborne diseases. This study is the first to investigate the effectiveness of TLF for a large-scale survey using a randomised, spot-sampling approach. The large-scale survey took place in Malawi, sub-Saharan Africa, in the dry season (n = 183). A subset of sources were revisited at the end of the following wet season (n = 41). The effectiveness of TLF was assessed by comparing TLF results to thermotolerant coliforms (TTC), humic-like fluorescence (HLF), inorganic hydrochemical data and sanitary risk scores. The most prominent differences in microbial water quality were observed between source types, with little variation between districts and seasons. TLF, TTCs, turbidity and sanitary risk scores were all elevated at alternative sources (shallow wells and tap stands) compared to hand-pumped boreholes. In the dry season, 18% of hand-pumped boreholes showed TTC contamination, which increase to 21% in the wet season. Groundwater recharge processes are likely responsible for seasonal variability of inorganic hydrochemistry at hand-pumped boreholes. TLF was able to distinguish no and low WHO risk classes (TTC 0-9 cfu/100 mL) from medium, high and very high risk classes (TTC 10 - >1000 cfu/100 mL). TLF failed to distinguish between no and low risk classes, which limits the use of TLF for assessing water quality to drinking water standards. This dataset indicates that HLF may raise baseline TLF for samples with low TLF values, increasing false positives. Therefore, TLF is better suited as a rapid high-level water quality screening tool to assess moderate and high levels of faecal contamination.


Assuntos
Água Potável , Monitoramento Ambiental , Humanos , Malaui , Estações do Ano , Inquéritos e Questionários , Triptofano , Microbiologia da Água , Qualidade da Água , Abastecimento de Água
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