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The Science of the Total Environment Jul 2023Mixed chlorine/chloramines are common in drinking water distribution systems (DWDSs); however, their transformation and impact on chemical and microbial characteristics...
Mixed chlorine/chloramines are common in drinking water distribution systems (DWDSs); however, their transformation and impact on chemical and microbial characteristics are not well understood. We systematically investigated water quality parameters associated with mixed chlorine/chloramine species conversion in 192 samples (including raw, finished, and tap water) collected throughout the year in a city in East China. Various chlorine/chloramine species (free chlorine, monochloramine [NHCl], dichloramine [NHCl], and organic chloramines [OC]) were detected in both chlorinated and chloraminated DWDSs. NHCl + OC increased with transport distance along the pipeline network. The maximum proportion of NHCl + OC in over total chlorine in tap water reached 66 % and 38 % from chlorinated and chloraminated DWDSs, respectively. Both free chlorine and NHCl showed a rapid decay in the water pipe systems, but NHCl and OC were more persistent. Correlations between chlorine/chloramine species and physicochemical parameters were established. Models for predicting the sum of chloroform/TCM, bromodichloromethane/BDCM, chlorodibromomethane/CBDM, and bromoform/TBM (THM) (R = 0.56) and haloacetic acids (HAAs) (R = 0.65) exhibited greater accuracy based on machine learning tuned with chlorine/chloramine species, particularly NHCl + OC. The predominant bacterial communities in mixed chlorine/chloramine systems were those resistant to chlorine or chloramine such as proteobacteria. NHCl was the most significant explanatory factor (28.1 %) for the variation in microbial community assemblage in chloraminated DWDSs. Although residual free chlorine and NHCl + OC, accounted for a smaller proportion of chlorine species in chloraminated DWDSs, they played an essential role (12.4 % and 9.1 %, respectively) in the microbial community structure.
Topics: Chloramines; Chlorine; Drinking Water; Water Quality; Water Purification; Disinfection
PubMed: 37028653
DOI: 10.1016/j.scitotenv.2023.163297 -
The Science of the Total Environment Oct 2023Disaggregated information on welfare indicators is useful for targeted policies. This study constructs geographic maps of water, sanitation, and hygiene (WASH) for...
Disaggregated information on welfare indicators is useful for targeted policies. This study constructs geographic maps of water, sanitation, and hygiene (WASH) for provinces and districts in Vietnam (which has 63 provinces and 712 districts). The study finds that poorer provinces and districts tend to have remarkably lower access to safely managed sanitation and water. Provinces in the Northern Midlands and Mountain Areas, and Central Highlands have the lowest level of access to safely managed sanitation and drinking water. There is a great variation in the availability of WASH facilities between districts within the same provinces. Additionally, the study highlights that districts with a higher population of ethnic minorities tend to experience lower rates of access to safely managed sanitation and drinking water. Even within the same district, moreover, ethnic minorities face greater challenges in accessing safely managed sanitation and drinking water compared to the majority Kinh population.
Topics: Drinking Water; Water Supply; Sanitation; Hygiene; Policy
PubMed: 37406684
DOI: 10.1016/j.scitotenv.2023.165277 -
Chemosphere Sep 2023The interaction between microplastics (MPs) and microorganisms may alter the distribution of antibiotic resistance genes (ARGs) in water and increase the ecological risk...
The interaction between microplastics (MPs) and microorganisms may alter the distribution of antibiotic resistance genes (ARGs) in water and increase the ecological risk of drinking water sources. To investigate the characteristics of MPs geographical distribution and its potential ecological risk in typical urban water, this study was conducted in Zhushan Bay, and we carried out a combination of tests to analyze the distribution of MPs and the migration changes of their surface microbial community composition and ARGs in different media by 16S rRNA gene high-throughput sequencing, non-targeted metabolomics and qPCR genomics in the near-shore (I), middle area (Ⅱ) and near-lake (Ⅲ) of Zhushan Bay. The results showed that MPs in fibrous form were dominant in the aquatic environment of Zhushan Bay; Polyurethane (PU) and Silicone were the main MPs types in Zhushan Bay. The abundance of MPs in the water of Zhushan Bay was winter > summer > autumn > spring; and in the sediment was winter > summer > autumn > spring, respectively. The distribution results of MPs in geographical location are as follows: In the water I > Ⅱ > Ⅲ, sediment exhibited Ⅱ > Ⅲ > I. The results indicate that physicochemical factors will affect the geographical distribution of MPs and their surface microbial community composition in the aquatic environment of Zhushan Bay. More cooperative behaviors and increased metabolically important pathways occurred in the microbial network on water-MPs compared to sediment-MPs. However, the microbial community in the sediment-MPs was more stable and had higher abundance of mobile genetic elements (MGEs). A total of 362 differential metabolites were detected, of which 193 were up-regulated and 19 down-regulated differential metabolites. blaTEM, Sul, and inti1 were prevalent in both the water and sediments of Zhushan Bay. Sul1 was most contaminated in ARGs. This study provides the latest field data and insights into MPs pollution in key aquatic environments.
Topics: Microplastics; Plastics; Bays; RNA, Ribosomal, 16S; Drinking Water; Genes, Bacterial; China; Anti-Bacterial Agents
PubMed: 37247671
DOI: 10.1016/j.chemosphere.2023.139024 -
Journal of Exposure Science &... Jan 2024
Topics: Humans; Drinking Water; Environmental Exposure
PubMed: 38429481
DOI: 10.1038/s41370-024-00639-0 -
The Science of the Total Environment Jul 2023Although it is known that freshwater resources are contaminated with microplastics (MPs), still limited information is known about the efficiency of large drinking water...
Although it is known that freshwater resources are contaminated with microplastics (MPs), still limited information is known about the efficiency of large drinking water treatment plants (DWTP) to remove microplastics. Moreover, reported concentrations of MPs in drinking water variates from some units to thousands of units per litre and the sampling volumes used for MPs analysis are generally heterogeneous and limited. The present study evaluates the removal of MPs and synthetic fibres in the main DWTP of Geneva, Switzerland, by considering large sampling volumes at different time intervals. Furthermore, contrary to other studies, this DWTP does not count with a clarification process before sand filtration and coagulated water is sent directly to sand filtration. In this study a distinction is made between microplastics as fragments, films, pellets, and synthetic fibres. Raw water and effluents of each filtering mass (sand and activated carbon filtration) are analysed for the presence of MPs and synthetic fibres with sizes ≥63 μm using infrared spectroscopy. Concentrations of MPs in raw water range from 25.7 to 55.6 MPs/m and in treated water from 0 to 4 MPs/m, respectively. Results show that 70 % of MPs are retained during sand filtration and total removal is equal to 97 % in treated water after activated carbon filtration. Concentration of identified synthetic fibres is low (average value of 2 synthetic fibres/m) and constant in all steps of water treatment. Chemical composition of microplastics and synthetic fibres is found more heterogeneous in raw water than after sand filtration and activated carbon filtration, indicating the persistence of some types of plastics (like polyethylene and polyethylene terephthalate) in water treatment processes. Heterogeneities in MP concentrations are observed from one sampling campaign to another, indicating significant variations of MP concentrations in raw water.
Topics: Microplastics; Plastics; Drinking Water; Switzerland; Sand; Charcoal; Water Pollutants, Chemical; Water Purification; Environmental Monitoring
PubMed: 37023809
DOI: 10.1016/j.scitotenv.2023.163270 -
Chemosphere Sep 2023Atrazine is a broad-spectrum herbicide widely used worldwide to control grassy and broadleaf weeds. Atrazine's popularity is attributable to its cost-effectiveness and...
Atrazine is a broad-spectrum herbicide widely used worldwide to control grassy and broadleaf weeds. Atrazine's popularity is attributable to its cost-effectiveness and reliable performance. Relatedly, it is also an important micropollutant with a potential negative impact on biodiversity and human health. Atrazine has long been regularly detected in several environmental compartments, and its widespread use has resulted in ubiquitous and unpreventable contamination. Among pesticides sold in Brazil, atrazine has remained among the top-ranked active ingredients for the last several years. Thus, this study aimed to evaluate the occurrence of atrazine and three degradation products (hydroxyatrazine, desisopropylatrazine, and desethylatrazine) in surface water (Capivari and Atibaia rivers) and treated water, monthly sampling from two drinking water treatment plants in Campinas (São Paulo, Brazil). An analytical method using solid-phase extraction (SPE) and liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed to determine target compounds simultaneously. The method presented instrument quantification limits from 0.5 to 4.0 ng mL and recovery values from 80 to 112%, with a maximum relative standard deviation of 6%. All analytes had a detection frequency of 100% from 2 to 2744 ng L. Statistical analysis showed no analyte removal after conventional water treatment. Also, the Capivari River showed greater analyte concentration than the Atibaia River. Performed risk assessments according to current Brazilian standards showed no human and environmental health risks. However, other risk assessment approaches may indicate potential risks, advocating for further research and ongoing surveillance.
Topics: Humans; Atrazine; Chromatography, Liquid; Drinking Water; Brazil; Tandem Mass Spectrometry; Water Pollutants, Chemical; Environmental Monitoring
PubMed: 37348619
DOI: 10.1016/j.chemosphere.2023.139289 -
Water Research Aug 2023The existence of disinfection by-products such as haloacetic acids (HAAs) in drinking water severely threatens water safety and public health. Nanofiltration (NF) is a...
The existence of disinfection by-products such as haloacetic acids (HAAs) in drinking water severely threatens water safety and public health. Nanofiltration (NF) is a promising strategy to remove HAAs for clean water production. However, NF often possesses overhigh rejection of essential minerals such as calcium. Herein, we developed highly selective NF membranes with tailored surface charge and pore size for efficient rejection of HAAs and high passage of minerals. The NF membranes were fabricated through interfacial polymerization (IP) with NaHCO as an additive. The NaHCO-tailored NF membranes exhibited high water permeance up to ∼24.0 L m h bar (more than doubled compared with the control membrane) thanks to the formation of stripe-like features and enlarged pore size. Meanwhile, the tailored membranes showed enhanced negative charge, which benefitted their rejection of HAAs and passage of Ca and Mg. The higher rejection of HAAs (e.g., > 90%) with the lower rejection of minerals (e.g., < 30% for Ca) allowed the NF membranes to achieve higher minerals/HAAs selectivity, which was significantly higher than those of commercially available NF membranes. The simultaneously enhanced membrane performance and higher minerals/HAAs selectivity would greatly boost water production efficiency and water quality. Our findings provide a novel insight to tailor the minerals/micropollutants selectivity of NF membranes for highly selective separation in membrane-based water treatment.
Topics: Drinking Water; Membranes, Artificial; Water Purification; Disinfection; Calcium
PubMed: 37356158
DOI: 10.1016/j.watres.2023.120255 -
International Journal of Environmental... Aug 2023Drinking water quality assessment is a major issue today, as it is crucial to supply safe drinking water to ensure the well-being of society. Predicting drinking water...
Drinking water quality assessment is a major issue today, as it is crucial to supply safe drinking water to ensure the well-being of society. Predicting drinking water quality helps strengthen water management and fight water pollution; technologies and practices for drinking water quality assessment are continuously improving; artificial intelligence methods prove their efficiency in this domain. This research effort seeks a hierarchical fuzzy model for predicting drinking water quality in Rome (Italy). The Mamdani fuzzy inference system is applied with different defuzzification methods. The proposed model includes three fuzzy intermediate models and one fuzzy final model. Each model consists of three input parameters and 27 fuzzy rules. A water quality assessment model is developed with a dataset that considers nine parameters (alkalinity, hardness, pH, Ca, Mg, fluoride, sulphate, nitrates, and iron). These nine parameters of drinking water are anticipated to be within the acceptable limits set to protect human health. Fuzzy-logic-based methods have been demonstrated to be appropriate to address uncertainty and subjectivity in drinking water quality assessment; they are an effective method for managing complicated, uncertain water systems and predicting drinking water quality. The proposed method can provide an effective solution for complex systems; this method can be modified easily to improve performance.
Topics: Humans; Water Quality; Drinking Water; Artificial Intelligence; Rome; Fuzzy Logic; Italy
PubMed: 37569062
DOI: 10.3390/ijerph20156522 -
Environmental Monitoring and Assessment Dec 2023In the hilly terrain of Nepal, springs are the main source of drinking water. With the increasing population, rapid urbanization, and unabated climate change, springs...
In the hilly terrain of Nepal, springs are the main source of drinking water. With the increasing population, rapid urbanization, and unabated climate change, springs are under the risk of survival. There is increasing evidence that springs in the mid-hills of Nepal are drying up, or are reducing in discharge, or are deteriorating by water quality. As a result, local communities are facing unprecedented water stress. On this background scenario, assessment of water quality of the springs in the Marin Watershed of Sindhuli district of Nepal was carried out in this study. Spring water samples were collected during the pre-monsoon and post-monsoon of 2020 and their hydrochemistry was analyzed. Further, springs' discharge was measured in situ and their criticality and sustainability were studied through community interaction. Results have revealed seasonal variation in spring discharge and spring water quality. Out of 39 flowing springs, water quality of 13, 8, and 6 springs, respectively, was very poor, poor, and unsuitable for drinking in the pre-monsoon. The count of springs with very poor, poor, and unsuitable drinking water quality during the post-monsoon was 8, 3, and 1, respectively. Occurrence of pathogenic bacteria (Escherichia coli) was identified in five spring samples which makes the spring water unsafe for drinking. Again, out of 51 springs studied, 12 are already dried up, and another 12 of the 39 flowing springs have become seasonal with very low discharge (0.03-0.07 L/s). The study highlights and emphasizes the need to protect the flowing springs and rejuvenate the dying springs of the Himalaya and of other parts of the world.
Topics: Water Quality; Drinking Water; Himalayas; Nepal; Environmental Monitoring
PubMed: 38110690
DOI: 10.1007/s10661-023-12186-6 -
Water Research Oct 2023Disinfection by-products (DBPs) with significant teratogenic and carcinogenic properties have become a growing concern among the public. As an efficient and...
Disinfection by-products (DBPs) with significant teratogenic and carcinogenic properties have become a growing concern among the public. As an efficient and environmentally friendly technology, non-thermal plasma offers potential for removing emerging micro-pollutants. In this study, the degradation performance of bubbling corona discharge was evaluated on 24 halogenated alicyclic and aliphatic DBPs present in drinking water at concentrations ranging from ng/L to μg/L. The degradation of DBPs followed pseudo-first-order kinetics with rate constants (k) in the descending order of halonitromethanes (HNMs), halogenated benzoquinones (HBQs), haloacetonitriles, trihalomethanes (THMs), haloketones, halogenated aldehydes, and haloacetic acids (HAAs). THMs, HNMs, and HBQs were effectively removed within 5 min under a discharge power of 28 W. Degradation rates achieved by plasma treatment surpass those of other conventional treatment technologies. The required energy consumption was in the range of 5-30 kW·h/m/order. Furthermore, the study investigated the effects of discharge power, initial concentration, and economic analysis on the degradation of four selected DBPs as representatives of mono-, di- and multi-carbon-containing DBPs, namely chloroform (TCM) and bromoform (TBM), tribromoacetic acid (TBAA), and 2,3,5,6-tetrachloro-1,4-benzoquinone (TetraC-BQ). Reactive radicals in the plasma system were investigated using electron paramagnetic resonance, optical emission spectroscopy, fluorimetry, and radical scavengers. Hydrated electrons and hydroxyl radicals played an important role in the removal of DBPs. The intermediates generated during the degradation of TCM, TBM, TBAA, and TetraC-BQ were identified, and the possible degradation pathways for mono- and binary C-DBPs and HBQs were deduced. The breakdown of HBQs did not produce secondary contamination with aliphatic DBPs. The carbon in DBPs was primarily converted to formic acid, acetic acid, and oxalic acid, and the halogens were mainly converted to halogen ions. Additionally, luminescent bacteria toxicity testing confirmed that plasma treatment could reduce the acute toxicity of water samples. These findings demonstrate the potential of plasma treatment as a post-treatment device at the household level.
Topics: Disinfection; Drinking Water; Disinfectants; Water Purification; Water Pollutants, Chemical; Halogens; Carbon; Trihalomethanes; Halogenation
PubMed: 37717329
DOI: 10.1016/j.watres.2023.120624