Kinetics and mechanism of abiotic decomposition of malodorous dimethyl disulfide under dark, oxic conditions

2019 ◽  
Vol 16 (3) ◽  
pp. 165 ◽  
Author(s):  
Tamir Buchshtav ◽  
Alon Amrani ◽  
Alexey Kamyshny Jr
Keyword(s):  
Drinking Water ◽  
Aqueous Solutions ◽  
Half Life ◽  
Distribution Systems ◽  
Water Distribution ◽  
Tap Water ◽  
Dimethyl Disulfide ◽  
Hydroxyl Ion ◽  
Abiotic Decomposition

Environmental contextDimethyl disulfide, a malodorous product of decomposing organic matter, can severely compromise the quality of drinking water. We studied the abiotic decomposition of dimethyl disulfide in aqueous solutions under dark, oxygenated conditions and found that the half-life varied from thousands to hundreds of thousands of years. The results indicate that in natural aquatic systems the decomposition of dimethyl disulfide is governed by other chemical, photochemical and microbial processes. AbstractThe presence of malodorous dimethyl polysulfides (DMPSs) has been documented in limnic systems as well as in tap water distribution systems. These compounds compromise the quality of drinking water. In this work, we studied kinetics and mechanisms of the decomposition reactions of the most abundant and stable DMPS, dimethyl disulfide (DMDS), in aqueous solutions in the presence of oxygen and absence of light. It was found that DMDS reacts with a hydroxyl ion and its decomposition leads to the formation of methyl mercaptan and other products. The decomposition reaction is of the first order with respect to both the concentration of DMDS and the activity of the hydroxyl ion, with an activation energy of 90±8kJmol−1. The half-life of DMDS under abiotic, dark, oxic conditions was observed to vary from thousands to hundreds of thousands of years depending on the pH and temperature. These results indicate that DMDS is decomposed by other chemical, photochemical and microbially-mediated pathways.

Decomposition of dimethyl polysulfides under solar irradiation in oxic aqueous solutions

2020 ◽  
Vol 17 (5) ◽  
pp. 377 ◽  
Author(s):  
Tamir Buchshtav ◽  
Alexey Kamyshny
Keyword(s):  
Drinking Water ◽  
Solar Radiation ◽  
Aqueous Solutions ◽  
Distribution Systems ◽  
Tap Water ◽  
Elevation Angle ◽  
Solar Irradiation ◽  
Quantum Yields ◽  
Radical Chain

Environmental contextThe quality of drinking water can be greatly compromised by the presence of dimethyl polysulfides. We studied the rate and mechanism of decomposition of dimethyl polysulfides in aqueous solution under solar irradiation, and found that they decompose photochemically in seconds to minutes, i.e. much faster than under dark conditions. These results suggest that photochemical pathways of dimethyl polysulfide decomposition may prevail in euphotic zones of natural aquatic systems. AbstractThe presence of malodorous dimethyl polysulfides (DMPSs) has been documented in marine and limnic systems as well as in tap water distribution systems. These compounds compromise the quality of drinking water. Under oxic conditions and in the absence of radiation, DMPSs with n ≥ 3 sulfur atoms disproportionate into DMPSs with n+1 and n−1 sulfur atoms, and, finally, to dimethyl disulfide (DMDS) and S8. DMDS, in turn, decomposes to methyl mercaptan (MT) and methanesulfinic acid. Under these conditions, the half-lives of DMPSs vary from months for dimethyl pentasulfide (DM5S) to hundreds of thousands of years for DMDS. In this work, we studied the kinetics and mechanisms of the decomposition reactions of DMPSs with 2–5 sulfur atoms in aqueous solutions in the presence of oxygen and under exposure to solar radiation. The quantum yields of decomposition of DMPSs with 2, 3, 4 and 5 sulfur atoms do not depend on either the concentration of DMPSs or pH, and are 40±10, 2.0±0.2, 35±10 and 10±4 respectively. The quantum yields, which are higher than unity, suggest that under exposure to solar radiation the photochemical decomposition of DMPSs proceeds by a radical chain reaction mechanism. Half-lives of DMPSs in oxic aquatic solutions exposed to solar radiation under a very clear atmosphere and a solar elevation angle of 90° were calculated from the quantum yields and were found to be as low as 43±13s for DMDS, 40±4s for dimethyl trisulfide (DMTS), 2.1±0.6s for dimethyl tetrasulfide (DM4S) and 4.2±1.7s for DM5S.

Pathogenic viruses in drinking-water biofilms: a public health risk?

Biofilms ◽  
2005 ◽  
Vol 2 (2) ◽  
pp. 105-117 ◽  
Author(s):  
S. Skraber ◽  
J. Schijven ◽  
C. Gantzer ◽  
A. M. de Roda Husman
Keyword(s):  
Drinking Water ◽  
Health Risk ◽  
Distribution Systems ◽  
Water Distribution ◽  
Tap Water ◽  
Field Studies ◽  
Pilot Scale ◽  
Drinking Water Distribution Systems ◽  
Virus Attachment ◽  
Pathogenic Viruses

Biofilms in drinking-water distribution systems may accumulate human pathogenic viruses. Viruses that attach to biofilm are removed from the water phase improving the water quality. However, if released in slough, it may still present a risk of infection. This review describes the available data on the presence of pathogenic viruses in drinking-water biofilms. First, biofilms of distribution systems potentially contribute to viral contamination of tap water only if infectious viruses are present initially in the water, which has been shown in several recent studies. However, only one out of three field studies showed the presence of infectious enteroviruses in natural biofilms from drinking-water networks. The presence of pathogenic viruses in biofilms points to the ability of these viruses to attach to biofilms. This has also been shown in pilot-scale studies in which bacteriophages and vaccine poliovirus strains were spiked into water and could be eluted from artificial biofilms. Reported attachment rates vary greatly and may depend on many factors such as the biofilm characteristics, the virus strain and the efficiency of viral recovery from biofilms. One study reported biphasic viral inactivation in biofilms with rapid initial inactivation followed by slow inactivation, implying that some of the attached viruses are able to remain infectious for a longer time. In several laboratory experiments, virus attachment to biofilms has been reported under various conditions; however, although detachment of sloughs in distribution systems has been observed, the presence of viruses in these sloughs was not studied. Here, we discuss the possible presence of infectious pathogenic viruses in sloughs; the extent to which these will pose a health risk remains to be investigated.

scholarly journals Socio-economic aspects of epidemiology of helicobateriosis

2019 ◽  
Vol 95 (9) ◽  
pp. 861-864
Author(s):  
Tatiana P. Fedichkina ◽  
L. G. Solenova ◽  
I. E. Zykova ◽  
S. V. German ◽  
A. V. Modestova ◽  
...  
Keyword(s):  
Public Health ◽  
Helicobacter Pylori ◽  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Water Distribution Systems ◽  
Helicobacter Pylori Infection ◽  
Technical State ◽  
Economic Aspects

There are considered special social and economic aspects of the epidemiology of Helicobacter pylori. These aspects acquired the particular importance for the last time due to the fact that the provision of the people with pure water has been becoming the focus of the attention of geopolitical and socio-economic interests in a number of countries. The availability ofpure drinking water serves a marker of the socio-economic state of the territory and the population living there. In Russia where different climatic conditions are deposited by considerable regional differences in the conditions of communal services caused both by various level of the socio-economic development of the territory, the supplementation with pure drinking water serves as the social determinant of the ecological conditions of the population’s life. This particularly has impact on the unfeasible technical state of the water distribution systems, microorganism ecology of which can substantially affect public health. The performed by authors a specialized screening ofpresented at the official web site of the joint-stock company «Mosvodokanal» current data concerning the quality of drinking water consumed by 2500 Moscovites, tested for the Helicobacter pylori infection revealed no deviations from the sanitary standards in the water received by the consumers. Along with that, the comparison of the map documents of the distribution of the Helicobacter pylori infection in Moscow with the distribution of citizens’ complaints of the decline of the quality of tap water has revealed a territorial fastening of the high values of the population infection rate of n^ylori and the urban sites with the greatest number of complaints. In the microbial ecology of water-distribution systems there are tightly aligned problems of their epidemiological safety, technical state and economic damage caused by corrosion as a result of microbiotic activity. In contrast to acute bacterial and viral infections which are deemed of the greatest importance when assessing the sanitary condition of water sources and water-distribution systems, the consequences of infection with H. pylori may not be manifestedfor a long time but some years later they may be manifested as serious chronic diseases (from gastritis to adenocarcinoma of the stomach and a wide range of extraintestinal pathologies), which causes great social and economic losses. Thus, the socio-economic aspect of the epidemiology of helicobacteriosis includes at least two components: the technic - the maintenance of the feasible technic and sanitary state of the water distribution systems and the medico-social - expenditures for screening and treatment of infected patients. In total they are an inseparable part of the prevention of socially-important diseases in the public health system.

Análise de sensibilidade às componentes do balanço hídrico para suporte a uma melhor gestão de perdas em sistemas de abastecimento de água

2020 ◽  
pp. 27
Author(s):  
Dália Loureiro ◽  
◽  
Aisha Mamade ◽  
Maria Almeida Silva ◽  
Francisco Arregui ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Balance ◽  
Water Loss ◽  
Distribution Systems ◽  
Water Distribution ◽  
Performance Indicator ◽  
Water Supply Systems ◽  
Water Balance Components ◽  
Non Revenue Water

Apesar da qualidade de serviço assegurada atualmente pelos sistemas de abastecimento de água (SAA) em Portugal, o valor de água não faturada nos sistemas em “baixa” tem-se mantido praticamente constante e com desempenho insatisfatório nos últimos anos. O balanço hídrico constitui um standard para avaliar a água entrada, o consumo faturado e não faturado em SAA. A quantificação fiável das componentes de água não faturada, para identificação dos principais problemas de perdas, constitui uma etapa preliminar crucial para a definição de um plano de gestão de perdas de água e de energia a médio prazo. No entanto, devido ao facto de várias componentes do balanço serem obtidas por estimativa, são necessárias abordagens que permitam o seu cálculo sistemático e uma avaliação da qualidade dos resultados com vista à redução das incertezas e a uma melhor avaliação da dimensão do problema. Este artigo analisa a incerteza das componentes do balanço hídrico, identifica alguns fatores que podem influenciar a qualidade da medição da água entrada e faz uma análise de sensibilidade ao indicador de perdas aparentes num conjunto de 22 entidades gestoras de sistemas de distribuição de água. Despite the high quality of service provided nowadays by drinking water supply systems in Portugal, the value of non-revenue water in drinking water distribution systems (DWDS) has been practically constant and with a poor service level in last years. The water balance is a standard for assessing system input volume, billed consumption and non-revenue water components in DWDS. Reliable quantification of non-revenue water components, for identification of the main problems, is an essential preliminary step in the definition of a plan for water loss and energy management in a medium-term horizon. However, because several components of the water balance are obtained by estimation, approaches are necessary to enable them to be systematically calculated and to evaluate the quality of results to reduce uncertainties and to better assess the water loss problems. This paper analyses the uncertainty associated with water balance components and the results of the apparent loss performance indicator in a set of 22 DWDS to establish reference values.

Review / SynthèseA review of drinking-water-associated endotoxin, including potential routes of human exposure

2002 ◽  
Vol 48 (7) ◽  
pp. 567-587 ◽  
Author(s):  
William B Anderson ◽  
Robin M Slawson ◽  
Colin I Mayfield
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Tap Water ◽  
Disinfection Byproducts ◽  
Potential Health ◽  
Biofilm Growth ◽  
Disinfection Byproduct ◽  
Drinking Water Distribution Systems ◽  
Drinking Water Distribution

In the past decade efforts have been made to reduce the formation of harmful disinfection byproducts during the treatment and distribution of drinking water. This has been accomplished in part by the introduction of processes that involve the deliberate encouragement of indigenous biofilm growth in filters. In a controlled environment, such as a filter, these biofilms remove compounds that would otherwise be available as disinfection byproduct precursors or support uncontrolled biological activity in distribution systems. In the absence of exposure to chlorinated water, most biofilm bacteria are gram negative and have an outer layer that contains endotoxin. To date, outbreaks of waterborne endotoxin-related illness attributable to contamination of water used in hemodialysis procedures have been only infrequently documented, and occurrences linked to ingestion or through dermal abrasions could not be located. However, a less obvious conduit, that of inhalation, has been described in association with aerosolized water droplets. This review summarizes documented drinking-water-associated incidents of endotoxin exposure attributable to hemodialysis and inhalation. Typical endotoxin levels in water and conditions under which substantial quantities can enter drinking water distribution systems are identified. It would appear that endotoxin originating in tap water can be inhaled but at present there is insufficient information available to quantify potential health risks.Key words: endotoxin, lipopolysaccharide, LPS, drinking water.

scholarly journals Devices for cleaning tap water

2019 ◽  
Vol 97 ◽  
pp. 01027
Author(s):  
Zhanna Govorova ◽  
Nikita Podlesnov ◽  
Vadim Govorov
Keyword(s):  
Drinking Water ◽  
Water Purification ◽  
Water Distribution ◽  
Tap Water ◽  
Distribution Network ◽  
Water Distribution Network ◽  
Calcium Content ◽  
Domestic Water ◽  
Common Causes

The condition of the water distribution network of the centralized water supply and its high wear, at the same time with other factors, affect the quality of drinking water transported to the consumer of drinking water. The most common causes of the secondary pollution of drinking water during its transportation are considered, as a result of which the concentration of dissolved and undissolved impurities and corrosion products increases, unpleasant smells and tastes appear in the water, microbiological and parasitological indicators deteriorate. Along with measures to improve the technology of water purification at waterworks, replacement, cleaning and repair of pipelines, in practice domestic water purification devices are used. The results of studies of the effectiveness of additional purification of drinking water are presented in the article. The water is taken for analysis from different points of the Moscow distribution network on water treatment devices: “JNT-RO”, filter “Aquafor”, installation “OSMO 300” with a capacity from 187.2 to 380 l/day. The results showed that the original tap water in its qualitative composition met the regulatory requirements for drinking water, and after passing through the elements of water purification devices during the stated service life the quality characteristics of turbidity - 100%, chromaticity - 84.6-100%, Total Dissolved Solids (TDS) - 84.4-94.2% and hardness - 87.3-93.8% improved. The calcium content in purified water ranged from 6.8 to 12 mg/l.

scholarly journals Virus contamination from operation and maintenance events in small drinking water distribution systems

2011 ◽  
Vol 9 (4) ◽  
pp. 799-812 ◽  
Author(s):  
Elisabetta Lambertini ◽  
Susan K. Spencer ◽  
Burney A. Kieke ◽  
Frank J. Loge ◽  
Mark A. Borchardt
Keyword(s):  
Drinking Water ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
Tap Water ◽  
Water Distribution Systems ◽  
Ultraviolet Disinfection ◽  
Drinking Water Distribution Systems ◽  
Virus Contamination ◽  
Drinking Water Distribution

We tested the association of common events in drinking water distribution systems with contamination of household tap water with human enteric viruses. Viruses were enumerated by qPCR in the tap water of 14 municipal systems that use non-disinfected groundwater. Ultraviolet disinfection was installed at all active wellheads to reduce virus contributions from groundwater to the distribution systems. As no residual disinfectant was added to the water, any increase in virus levels measured downstream at household taps would be indicative of distribution system intrusions. Utility operators reported events through written questionnaires. Virus outcome measures were related to distribution system events using binomial and gamma regression. Virus concentrations were elevated in the wells, reduced or eliminated by ultraviolet disinfection, and elevated again in distribution systems, showing that viruses were, indeed, directly entering the systems. Pipe installation was significantly associated with higher virus levels, whereas hydrant flushing was significantly associated with lower virus levels. Weak positive associations were observed for water tower maintenance, valve exercising, and cutting open a water main. Coliform bacteria detections from routine monitoring were not associated with viruses. Understanding when distribution systems are most vulnerable to virus contamination, and taking precautionary measures, will ensure delivery of safe drinking water.

scholarly journals Prevalence of Antibiotic Resistance in Drinking Water Treatment and Distribution Systems

2009 ◽  
Vol 75 (17) ◽  
pp. 5714-5718 ◽  
Author(s):  
Chuanwu Xi ◽  
Yongli Zhang ◽  
Carl F. Marrs ◽  
Wen Ye ◽  
Carl Simon ◽  
...  
Keyword(s):  
Drinking Water ◽  
Antibiotic Resistance ◽  
Water Treatment ◽  
Distribution Systems ◽  
Water Distribution ◽  
Tap Water ◽  
Water Distribution Systems ◽  
Drinking Water Treatment ◽  
Molecular Techniques ◽  
Source Water

ABSTRACT The occurrence and spread of antibiotic-resistant bacteria (ARB) are pressing public health problems worldwide, and aquatic ecosystems are a recognized reservoir for ARB. We used culture-dependent methods and quantitative molecular techniques to detect and quantify ARB and antibiotic resistance genes (ARGs) in source waters, drinking water treatment plants, and tap water from several cities in Michigan and Ohio. We found ARGs and heterotrophic ARB in all finished water and tap water tested, although the amounts were small. The quantities of most ARGs were greater in tap water than in finished water and source water. In general, the levels of bacteria were higher in source water than in tap water, and the levels of ARB were higher in tap water than in finished water, indicating that there was regrowth of bacteria in drinking water distribution systems. Elevated resistance to some antibiotics was observed during water treatment and in tap water. Water treatment might increase the antibiotic resistance of surviving bacteria, and water distribution systems may serve as an important reservoir for the spread of antibiotic resistance to opportunistic pathogens.

Synthesis of Lead Pyrophosphate, Pb2P2O7, in Water

2008 ◽  
Vol 14 (4) ◽  
pp. 335-341
Author(s):  
Darren A. Lytle ◽  
Colin White ◽  
Michael R. Schock
Keyword(s):  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Elevated Temperatures ◽  
Negative Impact ◽  
Tap Water ◽  
Drinking Water Distribution Systems ◽  
Water Ph ◽  
Lead Levels ◽  
Lead Pyrophosphate

Polyphosphates are used in drinking water to prevent the precipitation of cations such as calcium and iron. The possible negative impact of using polyphosphates is the undesirable complexation of lead that could result in elevated lead levels in consumers' tap water. Although the water industry has focused on complexation, lead polyphosphate solids such as lead pyrophosphate, Pb2P2O7, have been considered in other fields and not been shown to form in water. The ability to form lead pyrophosphate in water could have a potential impact on the strategies used to reduce lead levels in drinking water distribution systems. The objective of this work was to determine whether lead pyrophosphate could form under simulated potable drinking water conditions. Lead pyrophosphate was synthesized in water (pH 8.2, 10 mg C/L, 2.7 mg Cl2/L) after 13 days of aging. The formation of lead pyrophosphate was confirmed by X-ray diffraction and microscopy analysis. Synthesis did not require elevated temperatures or microwave assisted approaches used by past researchers. The findings suggest that lead (and possibly other metal) pyrophosphates could conceivably form in real drinking water systems, although much more work is necessary to determine the chemistry and kinetic boundaries.

PIXE ELEMENTAL ANALYSIS OF DRINKING WATER SUPPLIES

2002 ◽  
Vol 12 (03n04) ◽  
pp. 209-215 ◽  
Author(s):  
H. Yamazaki ◽  
K. Ishii ◽  
Y. Takahashi ◽  
Ts. Amartaivan ◽  
S. Matsuyama ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Drinking Water ◽  
Distribution Systems ◽  
Water Distribution ◽  
Fine Particles ◽  
Tap Water ◽  
Elemental Distribution ◽  
Pixe Analysis ◽  
Untreated Water ◽  
Fast Procedure

In this study, we carried out PIXE analysis of raw and treated water at five water treatment plants as well as of tap water from several houses located in each supply route. We used a simple fast procedure for preparing thin uniform targets of inorganic components in both soluble and insoluble fractions of aqueous samples in combination with preconcentration of trace heavy metals; that is, Nuclepore filtration targets for coarse particles, preconcentration targets for heavy metal ions and deposit targets for fine particles and soluble major constituents. The target preparation and the PIXE measurement are not time-consuming, and a broad range of concentrations (several tenths of ppb to a few tens of ppm) of 19 elements from Na to Pb is determined simultaneously with a precision sufficient to reveal the elemental distribution in the soluble and insoluble fractions. Tap water quality was examined as a function of elemental distribution in untreated water at the plants. We confirmed the increase of insoluble components of some heavy metals in untreated water taken from river due to heavy rainfall and the elution of Cu , Zn and Pb in drinking water by corrosion of the piping in some part of the water distribution systems.

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