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Environmental Science and Pollution... May 2015Fluorescence excitation emission matrices-parallel factor analysis (EEM-PARAFAC) is a powerful tool for characterizing dissolved organic matter (DOM), and it is applied... (Review)
Review
Fluorescence excitation emission matrices-parallel factor analysis (EEM-PARAFAC) is a powerful tool for characterizing dissolved organic matter (DOM), and it is applied in a rapidly growing number of studies on drinking water and wastewater treatments. This paper presents an overview of recent findings about the occurrence and behavior of PARAFAC components in drinking water and wastewater treatments, as well as their feasibility for assessing the treatment performance and water quality including disinfection by-product formation potentials (DBPs FPs). A variety of humic-like, protein-like, and unique (e.g., pyrene-like) fluorescent components have been identified, providing valuable insights into the chemical composition of DOM and the effects of various treatment processes in engineered systems. Coagulation/flocculation-clarification preferentially removes humic-like components, and additional treatments such as biological activated carbon filtration, anion exchange, and UV irradiation can further remove DOM from drinking water. In contrast, biological treatments are more effective for protein-like components in wastewater treatments. PARAFAC components have been proven to be valuable as surrogates for conventional water quality parameter, to track the changes of organic matter quantity and quality in drinking water and wastewater treatments. They are also feasible for assessing formations of trihalomethanes and other DBPs and evaluating treatment system performance. Further studies of EEM-PARAFAC for assessing the effects of the raw water quality and variable treatment conditions on the removal of DOM, and the formation potentials of various emerging DBPs, are essential for optimizing the treatment processes to ensure treated water quality.
Topics: Disinfection; Drinking Water; Factor Analysis, Statistical; Filtration; Humic Substances; Spectrometry, Fluorescence; Trihalomethanes; Wastewater; Water Pollutants, Chemical; Water Purification; Water Quality
PubMed: 25854204
DOI: 10.1007/s11356-015-4214-3 -
International Journal of Environmental... Dec 2018In many regions where drinking water supply is intermittent and unreliable, households adapt by storing water in cisterns or rooftop tanks. Both intermittent supply and...
In many regions where drinking water supply is intermittent and unreliable, households adapt by storing water in cisterns or rooftop tanks. Both intermittent supply and stored water can be vulnerable to contamination by microorganisms with deleterious health effects. The Metropolitan Zone of Guadalajara is a rapidly growing urban center with over five million residents where household storage is nearly ubiquitous. This pilot study was conducted in July 2018 to examine the microbiological quality of drinking water in Guadalajara. Samples were tested for free available chlorine residual, total coliform bacteria, and . A survey on access to water and public perspectives was also conducted. Water exiting rooftop tanks exceeded regulatory limits for total coliform levels in half of the homes studied. Piped water arriving at two homes had total coliform levels that far exceeded regulatory limits. No were detected in any of the samples. Only 35% of homes had a chlorine residual between the recommended 0.2 and 1.5 mg/L. Many homes reported unpleasant odors and colors. Only 7% of residents drank the piped water. Future studies are needed, especially during April and May when many homes reported a higher disruption to water service.
Topics: Chlorine; Drinking Water; Humans; Mexico; Pilot Projects; Water Purification; Water Quality; Water Supply
PubMed: 30591690
DOI: 10.3390/ijerph16010067 -
Environmental Pollution (Barking, Essex... Jun 2020Microplastics have become an inevitable component of our environment. Worldwide, free public fountains are common and one of the best sources of drinking water which are...
Microplastics have become an inevitable component of our environment. Worldwide, free public fountains are common and one of the best sources of drinking water which are being installed with one of the viewpoints of reducing single-use plastics bottle consumption. However, the state of knowledge on how microplastics might be affecting in those free public drinking fountains is unknown. In this study, free drinking water fountains from 42 metro stations in Mexico City were being looked into for the occurrence of microplastics and investigated their shape type, size, abundance, distribution, polymer composition and surface morphology. Microplastics were detected in all the samples analyzed. The results revealed the significant abundance of microplastics ranging from 5 ± 2 to 91 ± 14 L in drinking water with an overall average of 18 ± 7 microplastics L. Transparent fibers (69%) were predominant in the identified microplastics followed by blue (24%) and red colored (7%) fibers. The most frequent microplastics dimensions ranged between 0.1 and 1 mm which is approximately 75% of the total microplastics. Micro-Raman spectroscopy analysis indicated that microplastics contained in drinking water were mainly polyesters (poly (trimethylene terephthalate)) and epoxy resin suggesting the possible contribution of wastewater discharges for microplastics contamination. Thus, this study findings show that free public drinking water fountains are potential microplastics hotspot for human consumption and provide useful references for mitigation measures.
Topics: Cities; Drinking Water; Environmental Monitoring; Humans; Mexico; Microplastics; Particle Size; Water Pollutants, Chemical
PubMed: 32113111
DOI: 10.1016/j.envpol.2020.114227 -
Journal of Environmental Health Oct 2016
Topics: Civil Defense; Communication; Disease Outbreaks; Drinking Water; Environmental Health; Environmental Monitoring; Humans; Public Health; Waterborne Diseases
PubMed: 29120153
DOI: No ID Found -
Tijdschrift Voor Diergeneeskunde Feb 2013Drinking water can be considered an essential nutrient for dairy cattle. However, because it comes from different sources, its chemical and microbiological quality does...
Drinking water can be considered an essential nutrient for dairy cattle. However, because it comes from different sources, its chemical and microbiological quality does not always reach accepted standards. Moreover, water quality is not routinely assessed on dairy farms. The microecology of drinking water sources and distribution systems is rather complex and still not fully understood. Water quality is adversely affected by the formation of biofilms in distribution systems, which form a persistent reservoir for potentially pathogenic bacteria. Saprophytic microorganisms associated with such biofilms interact with organic and inorganic matter in water, with pathogens, and even with each other. In addition, the presence of biofilms in water distribution systems makes cleaning and disinfection difficult and sometimes impossible. This article describes the complex dynamics of microorganisms in water distribution systems. Water quality is diminished primarily as a result of faecal contamination and rarely as a result of putrefaction in water distribution systems. The design of such systems (with/ without anti-backflow valves and pressure) and the materials used (polyethylene enhances biofilm; stainless steel does not) affect the quality of water they provide. The best option is an open, funnel-shaped galvanized drinking trough, possibly with a pressure system, air inlet, and anti-backflow valves. A poor microbiological quality of drinking water may adversely affect feed intake, and herd health and productivity. In turn, public health may be affected because cattle can become a reservoir of microorganisms hazardous to humans, such as some strains of E. coli, Yersinia enterocolitica, and Campylobacter jejuni. A better understanding of the biological processes in water sources and distribution systems and of the viability of microorganisms in these systems may contribute to better advice on herd health and productivity at a farm level. Certain on-farm risk factors for water quality have been identified. A practical approach will facilitate the control and management of these risks, and thereby improve herd health and productivity.
Topics: Animals; Biofilms; Cattle; Dairying; Disease Reservoirs; Drinking; Drinking Water; Feces; Female; Microbial Viability; Public Health; Risk Assessment; Water Microbiology
PubMed: 23457917
DOI: No ID Found -
Environmental Health Perspectives Mar 2014Safe drinking water is essential for well-being. Although microbiological contamination remains the largest cause of water-related morbidity and mortality globally,... (Review)
Review
BACKGROUND
Safe drinking water is essential for well-being. Although microbiological contamination remains the largest cause of water-related morbidity and mortality globally, chemicals in water supplies may also cause disease, and evidence of the human health consequences is limited or lacking for many of them.
OBJECTIVES
We aimed to summarize the state of knowledge, identify gaps in understanding, and provide recommendations for epidemiological research relating to chemicals occurring in drinking water.
DISCUSSION
Assessing exposure and the health consequences of chemicals in drinking water is challenging. Exposures are typically at low concentrations, measurements in water are frequently insufficient, chemicals are present in mixtures, exposure periods are usually long, multiple exposure routes may be involved, and valid biomarkers reflecting the relevant exposure period are scarce. In addition, the magnitude of the relative risks tends to be small.
CONCLUSIONS
Research should include well-designed epidemiological studies covering regions with contrasting contaminant levels and sufficient sample size; comprehensive evaluation of contaminant occurrence in combination with bioassays integrating the effect of complex mixtures; sufficient numbers of measurements in water to evaluate geographical and temporal variability; detailed information on personal habits resulting in exposure (e.g., ingestion, showering, swimming, diet); collection of biological samples to measure relevant biomarkers; and advanced statistical models to estimate exposure and relative risks, considering methods to address measurement error. Last, the incorporation of molecular markers of early biological effects and genetic susceptibility is essential to understand the mechanisms of action. There is a particular knowledge gap and need to evaluate human exposure and the risks of a wide range of emerging contaminants.
CITATION
Villanueva CM, Kogevinas M, Cordier S, Templeton MR, Vermeulen R, Nuckols JR, Nieuwenhuijsen MJ, Levallois P. 2014. Assessing exposure and health consequences of chemicals in drinking water: current state of knowledge and research needs. Environ Health Perspect 122:213–221; http://dx.doi.org/10.1289/ehp.1206229
Topics: Drinking Water; Environmental Exposure; Environmental Monitoring; Humans; Risk Assessment; Water Pollutants, Chemical
PubMed: 24380896
DOI: 10.1289/ehp.1206229 -
Environmental Science & Technology Sep 2020Bacterial communities in biofilters can improve drinking water quality through the biodegradation of dissolved contaminants but also pose potential risks by harboring...
Bacterial communities in biofilters can improve drinking water quality through the biodegradation of dissolved contaminants but also pose potential risks by harboring and shedding microbes into the drinking water distribution system. In this study, pilot-scale granular activated carbon (GAC)-sand and anthracite-sand pilot-scale biofilters were investigated to determine the effects of filter design and operation on the microbiome of the filter media and its relationship to the microbiome in the filter effluent water. Bacterial abundance in the biofilters was relatively stable over time. Bacterial community composition exhibited spatial variation (i.e., with bed depth) and temporal variation linked to water quality changes. Bacterial community composition was significantly affected by the media type (GAC vs anthracite) and backwashing strategy (chloraminated water vs nonchloraminated water). The biofilters reduced bacterial abundance in the water (∼70%) but had only a minor effect on the bacterial community composition in the filtrate. Overall, our results suggest that the bacterial communities growing on biofilters affect filtered water quality primarily through the biotransformation of pollutants and nutrients rather than by altering the microbial community composition of the water as it passes through the filter.
Topics: Charcoal; Drinking Water; Filtration; Microbiota; Water Purification
PubMed: 32786579
DOI: 10.1021/acs.est.0c01730 -
Chemosphere Dec 2020Halogenated acetaldehydes (HALs) are widely considered to be the third largest group of identified disinfection by-products (DBPs) by weight in drinking water. In this...
Halogenated acetaldehydes (HALs) are widely considered to be the third largest group of identified disinfection by-products (DBPs) by weight in drinking water. In this study, we evaluated various scenarios for the domestic handling of drinking water and their effects on HALs. Two drinking water systems (DS1 and DS2) were selected for this case study. First, tap water samples that were collected in DS1 at different time and from different locations were subjected to three domestic handling scenarios: boiling, domestic filtration using a point-of-use device with a new filter followed by refrigeration, and refrigeration in a covered glass pitcher. In the last two scenarios, the maximum storage (refrigeration) time was 24 h. Second, two water samples each from DS1 and DS2 were collected to investigate the effects that heating water to different temperatures has on HALs. According to the results, boiling the water effectively removed most HALs except dichloroacetaldehyde (DCAL), which increased. In contrast to the variable behaviors of HALs after boiling, all HALs were consistently and significantly reduced by domestic filtration. However, the overall removal efficiency of HALs from filtration (65%) was considerably lower than that from boiling (85%). Finally, refrigeration had no significant impact on the overall concentration of total HALs. However, chloral hydrate levels increased in unfiltered water after refrigeration, likely due to the reaction of chlorine residuals and precursors present in water. Therefore, boiling and domestic filtering of tap water may be recommended for the removal of HALs prior to consuming tap water.
Topics: Acetaldehyde; Chlorine; Disinfectants; Disinfection; Drinking Water; Filtration; Halogenation; Water Pollutants, Chemical; Water Purification; Water Supply
PubMed: 32707319
DOI: 10.1016/j.chemosphere.2020.127531 -
Patterns and predictions of drinking water nitrate violations across the conterminous United States.The Science of the Total Environment Jun 2020Excess nitrate in drinking water is a human health concern, especially for young children. Public drinking water systems in violation of the 10 mg nitrate-N/L maximum...
Excess nitrate in drinking water is a human health concern, especially for young children. Public drinking water systems in violation of the 10 mg nitrate-N/L maximum contaminant level (MCL) must be reported in EPA's Safe Drinking Water Information System (SDWIS). We used SDWIS data with random forest modeling to examine the drivers of nitrate violations across the conterminous U.S. and to predict where public water systems are at risk of exceeding the nitrate MCL. As explanatory variables, we used land cover, nitrogen inputs, soil/hydrogeology, and climate variables. While we looked at the role of nitrate treatment in separate analyses, we did not include treatment as a factor in the final models, due to incomplete information in SDWIS. For groundwater (GW) systems, a classification model correctly classified 79% of catchments in violation and a regression model explained 43% of the variation in nitrate concentrations above the MCL. The most important variables in the GW classification model were % cropland, agricultural drainage, irrigation-to-precipitation ratio, nitrogen surplus, and surplus precipitation. Regions predicted to have risk for nitrate violations in GW were the Central California Valley, parts of Washington, Idaho, the Great Plains, Piedmont of Pennsylvania and Coastal Plains of Delaware, and regions of Wisconsin, Iowa, and Minnesota. For surface water (SW) systems, a classification model correctly classified 90% of catchments and a regression model explained 52% of the variation in nitrate concentration. The variables most important for the SW classification model were largely hydroclimatic variables including surplus precipitation, irrigation-to-precipitation ratio, and % shrubland. Areas at greatest risk for SW nitrate violations were generally in the non-mountainous west and southwest. Identifying the areas with possible risk for future violations and potential drivers of nitrate violations across U.S. can inform decisions on how source water protection and other management options could best protect drinking water.
Topics: Drinking Water; Nitrates; United States; Water Pollutants, Chemical; Water Supply
PubMed: 32192969
DOI: 10.1016/j.scitotenv.2020.137661 -
Australian and New Zealand Journal of... Aug 2018The main aim of this study was to determine the content of fluoride in drinking water from sources within the sampling areas for the National Oral Health Survey (NOHS)...
OBJECTIVE
The main aim of this study was to determine the content of fluoride in drinking water from sources within the sampling areas for the National Oral Health Survey (NOHS) 2011 from the Central, Northern, Western and Eastern Divisions in the Fiji Islands.
METHOD
Drinking water samples were collected from taps, a waterfall, wells, creeks, streams, springs, rivers, boreholes and rain water tanks in a diverse range of rural and urban areas across the Fiji Islands. A total of 223 areas were sampled between December 2014 and June 2015. Samples were analysed for fluoride using a colorimetric assay with the Zirconyl-SPADNS Reagent. The samples were pre-treated with sodium arsenite solution prior to analysis to eliminate interference from chlorine.
RESULTS
Measured fluoride concentrations ranged from 0.01 to 0.35 ppm, with a mean concentration across all samples of 0.03 + 0.04 ppm. No samples achieved the optimal level for caries prevention (0.7 ppm). The Western Division had the highest fluoride levels compared to the other Divisions. The highest single fluoride concentration was found in Valase. The drinking water for this rural area located in the Western Division is from a borehole. The lowest concentrations of fluoride were in reticulated water samples from rural areas in the Central Division, which were consistently less than those recorded in the Northern, Eastern and Western Divisions.
CONCLUSION
All samples had fluoride concentrations below the optimum level required to prevent dental caries. Implications for public health: This research forms part of the objectives of the 2011 National Oral Health Survey in Fiji. At present, Fiji lacks water fluoridation and therefore a baseline of the fluoride content in drinking water supplies is essential before water fluoridation is implemented. The results from this study would be beneficial in designing caries-preventive strategies through water fluoridation and for comparing those strategies with caries prevalence overtime.
Topics: Dental Caries; Dental Health Surveys; Drinking Water; Fiji; Fluoridation; Fluorides; Humans; Rural Population; Surveys and Questionnaires; Urban Population; Water Supply
PubMed: 29697882
DOI: 10.1111/1753-6405.12787