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Water Research Nov 2017Treated drinking water may become contaminated while travelling in the distribution system on the way to consumers. Elevated dissolved organic matter (DOM) at the tap...
Treated drinking water may become contaminated while travelling in the distribution system on the way to consumers. Elevated dissolved organic matter (DOM) at the tap relative to the water leaving the treatment plant is a potential indicator of contamination, and can be measured sensitively, inexpensively and potentially on-line via fluorescence and absorbance spectroscopy. Detecting elevated DOM requires potential contamination events to be distinguished from natural fluctuations in the system, but how much natural variation to expect in a stable distribution system is unknown. In this study, relationships between DOM optical properties, microbial indicator organisms and trace elements were investigated for households connected to a biologically-stable drinking water distribution system. Across the network, humic-like fluorescence intensities showed limited variation (RSD = 3.5-4.4%), with half of measured variation explained by interactions with copper. After accounting for quenching by copper, fluorescence provided a very stable background signal (RSD < 2.2%) against which a ∼2% infiltration of soil water would be detectable. Smaller infiltrations would be detectable in the case of contamination by sewage with a strong tryptophan-like fluorescence signal. These findings indicate that DOM fluorescence is a sensitive indicator of water quality changes in drinking water networks, as long as potential interferents are taken into account.
Topics: Copper; Drinking Water; Fluorescence; Humic Substances; Sewage; Soil; Spectrometry, Fluorescence; Water Microbiology; Water Pollutants, Chemical; Water Quality
PubMed: 28822814
DOI: 10.1016/j.watres.2017.08.020 -
Ecotoxicology and Environmental Safety Aug 2019Polycyclic aromatic hydrocarbons (PAHs) are a kind of persistent toxic substances, which have been frequently detected in environmental media. However, studies on their...
Polycyclic aromatic hydrocarbons (PAHs) are a kind of persistent toxic substances, which have been frequently detected in environmental media. However, studies on their occurrences and distributions in drinking water are insufficient and their composition profiles in drinking water are still not clear. In this study, we investigated 16 priority polycyclic aromatic hydrocarbons (PAHs) in drinking water from different administrative level cities throughout mainland China, analyzed the influences of anthropogenic activities on PAHs, and assessed the health risk of the PAHs in drinking water. On the national scale, the sum concentration of the 16 priority-controlled PAHs (∑PAHs) designated by the U.S. Environmental Protection Agency (USEPA) was in a range of 3.89-231.39 (mean 56.25) ng L. With the decline of ∑PAHs, the concentration of 3-ring PAHs decreased, while its proportion increased, indicating 3-ring PAHs might be more difficult to remove than other PAHs in drinking water. The geographical distribution of PAHs in drinking water of China was in a descending order of West (69.81 ng L) > South (61.95 ng L) > North (58.63 ng L) > East (39.21 ng L) > Northeast China (37.93 ng L). ∑PAHs in drinking water of Prefecture-level City was the greatest (71.49 ng L) followed by Provincial Capital (52.12 ng L), County-level City (50.98 ng L) and Municipality (33.92 ng L). ∑PAHs was significantly negatively correlated with the per capita GDP of sampling city (P < 0.01, n = 78), implying that waterworks is an effective way to control and reduce PAH pollution in drinking water. The carcinogenic risk of the 16 PAHs in drinking water of China was much greater than the non-carcinogenic risk.
Topics: Carcinogens; China; Cities; Drinking Water; Environmental Monitoring; Environmental Pollution; Polycyclic Aromatic Hydrocarbons; Risk Assessment; Water Pollutants, Chemical
PubMed: 30978653
DOI: 10.1016/j.ecoenv.2019.03.119 -
Public Health Reports (Washington, D.C.... 2024Reports of unsafe school drinking water in the United States highlight the importance of ensuring school water is safe for consumption. Our objectives were to describe...
OBJECTIVES
Reports of unsafe school drinking water in the United States highlight the importance of ensuring school water is safe for consumption. Our objectives were to describe (1) results from our recent school drinking water sampling of 5 common contaminants, (2) school-level factors associated with exceedances of various water quality standards, and (3) recommendations.
METHODS
We collected and analyzed drinking water samples from at least 3 sources in 83 schools from a representative sample of California public schools from 2017 through 2022. We used multivariate logistic regression to examine school-level factors associated with lead in drinking water exceedances at the American Academy of Pediatrics (AAP) recommendation level (1 part per billion [ppb]) and state action-level exceedances of other contaminants (lead, copper, arsenic, nitrate, and hexavalent chromium).
RESULTS
No schools had state action-level violations for arsenic or nitrate; however, 4% had ≥1 tap that exceeded either the proposed 10 ppb action level for hexavalent chromium or the 1300 ppb action level for copper. Of first-draw lead samples, 4% of schools had ≥1 tap that exceeded the California action level of 15 ppb, 18% exceeded the US Food and Drug Administration (FDA) bottled water standard of 5 ppb, and 75% exceeded the AAP 1 ppb recommendation. After turning on the tap and flushing water for 45 seconds, 2%, 10%, and 33% of schools exceeded the same standards, respectively. We found no significant differences in demographic characteristics between schools with and without FDA or AAP exceedances.
CONCLUSIONS
Enforcing stricter lead action levels (<5 ppb) will markedly increase remediation costs. Continued sampling, testing, and remediation efforts are necessary to ensure drinking water meets safety standards in US schools.
Topics: California; Schools; Drinking Water; Humans; Water Pollutants, Chemical; Arsenic; Nitrates; Water Quality; Chromium; Water Supply; Lead; Copper
PubMed: 37667618
DOI: 10.1177/00333549231192471 -
The American Journal of Tropical... Oct 2017Consumption of drinking water from private vendors has increased considerably in Port-au-Prince, Haiti, in recent decades. A major type of vendor is private kiosks,...
Consumption of drinking water from private vendors has increased considerably in Port-au-Prince, Haiti, in recent decades. A major type of vendor is private kiosks, advertising reverse osmosis-treated water for sale by volume. To describe the scale and geographical distribution of private kiosks in metropolitan Port-au-Prince, an inventory of private kiosks was conducted from July to August 2013. Coordinates of kiosks were recorded with global positioning system units and a brief questionnaire was administered with the operator to document key kiosk characteristics. To assess the quality of water originating from private kiosks, water quality analyses were also conducted on a sample of those inventoried as well as from the major provider company sites. The parameters tested were , free chlorine residual, pH, turbidity, and total dissolved solids. More than 1,300 kiosks were inventoried, the majority of which were franchises of four large provider companies. Approximately half of kiosks reported opening within 12 months of the date of the inventory. The kiosk treatment chain and sales price was consistent among a majority of the kiosks. Of the 757 kiosks sampled for water quality, 90.9% of samples met World Health Organization (WHO) microbiological guideline at the point of sale for nondetectable in a 100-mL sample. Of the eight provider company sites tested, all samples met the WHO microbiological guideline. Because of the increasing role of the private sector in drinking water provision in Port-au-Prince and elsewhere in Haiti, this assessment was an important first step for government regulation of this sector.
Topics: Chlorine; Commerce; Disasters; Drinking Water; Earthquakes; Escherichia coli; Haiti; Humans; Hydrogen-Ion Concentration; Private Sector; Water Quality
PubMed: 29064355
DOI: 10.4269/ajtmh.16-0692 -
Journal of Environmental and Public... 2019The shortage of fresh water creates acute challenges in the West Bank of Palestine. Springs provide a main water resource in the West Bank. Investigating springs' water...
The shortage of fresh water creates acute challenges in the West Bank of Palestine. Springs provide a main water resource in the West Bank. Investigating springs' water quality is essential step for promoting their public use. The aim of this research is to assess the microbiological and physiochemical quality parameters of drinking water from springs. The study methodology included sampling through field work and laboratory testing for water quality parameters using standard procedures. The study area covered all locations containing licensed springs by the Palestinian Water Authority in the West Bank of Palestine. The number of collected samples was 127 covering 300 springs. The chemical, physical, and biological parameters for each sample were measured. Then, the obtained characteristics were evaluated based on national and international quality standards (PSI and WHO). The investigated parameters included temperature, pH, EC, total hardness, concentrations of nitrate, sodium ions, total chlorine, residual chlorine, turbidity, and total and faecal coliforms. Most of investigated physical and chemical parameters were within the acceptable standard limits. However, the turbidity and chloride and nitrate concentrations exceeded standard limits. The findings indicate that only a minor fraction of the samples (2%) requires chlorination treatment, while most of the springs (97% of samples) are classified as possessing no risk.
Topics: Drinking Water; Feces; Middle East; Natural Springs; Water Pollutants, Chemical; Water Quality
PubMed: 31341486
DOI: 10.1155/2019/8631732 -
Chemosphere Jan 2019Increasing micropollutant and cyanobacterial contamination of drinking water threatens human health worldwide. However, these contaminates are not efficiently removed by...
Increasing micropollutant and cyanobacterial contamination of drinking water threatens human health worldwide. However, these contaminates are not efficiently removed by common drinking water treatment processes, and thus additional treatments are frequently required. Recent investigations have demonstrated that KMnO pre-oxidation can efficiently remove some micropollutants and cyanobacteria but the release of cyanobacterial toxins and Mn limit its use. To overcome these problems, we proposed a KMnO pre-oxidation coupled with bioaugmentation (e.g., sand filtration) method to treat micropollutant- and cyanobacteria-laden water. We used 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid (BP-4, a common micropollutant in drinking water sources) and Microcystis aeruginosa (a widely distributed cyanobacterial species) as model pollutants to verify the feasibility of the proposed method. Results revealed that KMnO pre-oxidation efficiently removed existing natural organic matter and Microcystis aeruginosa but failed to remove BP-4 and released Mn and microcystin-LR (MC-LR) during treatment. Following the addition of a manganese-oxidizing bacterial strain (Pseudomonas sp. QJX-1) to the KMnO-treated solution, we found that the bacteria could transform Mn to Mn(III&IV) oxides, with the formed Mn oxides then able to remove BP-4 and MC-LR. Overall, the proposed method exhibited advantages in the removal of natural organic matter (i.e., decreasing disinfection byproduct formation), micropollutants, and cyanobacteria as well as preventing the release of Mn, and thus may be considered a good alternative for treating polluted drinking water.
Topics: Biodegradation, Environmental; Cyanobacteria; Disinfection; Drinking Water; Humans; Oxidation-Reduction; Potassium Permanganate; Water Pollutants, Chemical; Water Purification
PubMed: 30300806
DOI: 10.1016/j.chemosphere.2018.10.013 -
The Science of the Total Environment Aug 2024Seven public water systems in Minnesota, USA were analyzed from one to five times over a two-year period to assess temporal changes in the concentrations of total...
Seven public water systems in Minnesota, USA were analyzed from one to five times over a two-year period to assess temporal changes in the concentrations of total bacteria, Legionella spp., and Legionella pneumophila from source (i.e., raw water) through the water treatment process to the end water user. Bacterial biomass was collected by filtering large volumes of raw water (12 to 425 L, median: 38 L) or finished and tap water (27 to 1205 L, median: 448 L) using ultrafiltration membrane modules. Quantitative PCR (qPCR) was then used to enumerate all bacteria (16S rRNA gene fragments), all Legionella spp. (ssrA), and Legionella pneumophila (mip). Total coliforms, Escherichia coli, and L. pneumophila also were quantified in the water samples via cultivation. Median concentrations of total bacteria and Legionella spp. (ssrA) in raw water (8.5 and 4.3 log copies/L, respectively) decreased by about 2 log units during water treatment. The concentration of Legionella spp. (ssrA) in water collected from distribution systems inversely correlated with the total chlorine concentration for chloraminated systems significantly (p = 0.03). Although only 8 samples were collected from drinking water distribution systems using free chlorine as a residual disinfectant, these samples had significantly lower concentrations of Legionella spp. (ssrA) than samples collected from the chloraminated systems (p = 5 × 10). There was considerable incongruity between the results obtained via cultivation-independent (qPCR) and cultivation-dependent assays. Numerous samples were positive for L. pneumophila via cultivation, none of which tested positive for L. pneumophilia (mip) via qPCR. Conversely, a single sample tested positive for L. pneumophilia (mip) via qPCR, but this sample tested negative for L. pneumophilia via cultivation. Overall, the results suggest that conventional treatment is effective at reducing, but not eliminating, Legionella spp. from surface water supplies and that residual disinfection is effective at suppressing these organisms within drinking water distribution systems.
Topics: Drinking Water; Legionella; Minnesota; Water Microbiology; Water Supply; Disinfectants; Water Purification
PubMed: 38788954
DOI: 10.1016/j.scitotenv.2024.173317 -
Toxicon : Official Journal of the... May 2016Desert environments and drylands experience a drastic scarcity of water resources. To alleviate dependence on freshwater for drinking water needs, countries have...
Desert environments and drylands experience a drastic scarcity of water resources. To alleviate dependence on freshwater for drinking water needs, countries have invested in infrastructure development of desalination plants. Collectively, the countries of the Arabian Gulf produce 45% of the world's desalinated water, which is stored in dams, mega-reservoirs and secondary house water tanks to secure drinking water beyond daily needs. Improper storage practices of drinking water in impoundments concomitant with increased temperatures and light penetration may promote the growth of cyanobacteria and accumulation of cyanotoxins. To shed light on this previously unexplored research area in desert environments, we examined drinking and irrigation water of urban and rural environments to determine whether cyanobacteria and cyanotoxins are present, and what are the storage and transportation practices as well as the environmental parameters that best predict their presence. Cyanobacteria were present in 80% of the urban and 33% of the rural water impoundments. Neurotoxins BMAA, DAB and anatoxin-a(S) were not detected in any of the water samples, although they have been found to accumulate in the desert soils, which suggests a bioaccumulation potential if they are leached into the aquifer. A toxic BMAA isomer, AEG, was found in 91.7% of rural but none of the urban water samples and correlated with water-truck transportation, light exposure and chloride ions. The hepatotoxic cyanotoxin microcystin-LR was present in the majority of all sampled impoundments, surpassing the WHO provisional guideline of 1 μg/l in 30% of the urban water tanks. Finally, we discuss possible management strategies to improve storage and transportation practices in order to minimize exposure to cyanobacteria and cyanotoxins, and actions to promote sustainable use of limited water resources.
Topics: Bacterial Toxins; Conservation of Natural Resources; Cyanobacteria; Desert Climate; Drinking Water; Groundwater; Water Purification; Water Supply
PubMed: 26921462
DOI: 10.1016/j.toxicon.2016.02.016 -
Environmental Research Jun 2024Dual-source drinking water distribution systems (DWDS) over single-source water supply systems are becoming more practical in providing water for megacities. However,...
Dual-source drinking water distribution systems (DWDS) over single-source water supply systems are becoming more practical in providing water for megacities. However, the more complex water supply problems are also generated, especially at the hydraulic junction. Herein, we have sampled for a one-year and analyzed the water quality at the hydraulic junction of a dual-source DWDS. The results show that visible changes in drinking water quality, including turbidity, pH, UV, DOC, residual chlorine, and trihalomethanes (TMHs), are observed at the sample point between 10 and 12 km to one drinking water plant. The average concentration of residual chlorine decreases from 0.74 ± 0.05 mg/L to 0.31 ± 0.11 mg/L during the water supplied from 0 to 10 km and then increases to 0.75 ± 0.05 mg/L at the end of 22 km. Whereas the THMs shows an opposite trend, the concentration reaches to a peak level at hydraulic junction area (10-12 km). According to parallel factor (PARAFAC) and high-performance size-exclusion chromatography (HPSEC) analysis, organic matters vary significantly during water distribution, and tryptophan-like substances and amino acids are closely related to the level of THMs. The hydraulic junction area is confirmed to be located at 10-12 km based on the water quality variation. Furthermore, data-driven models are established by machine learning (ML) with test R higher than 0.8 for THMs prediction. And the SHAP analysis explains the model results and identifies the positive (water temperature and water supply distance) and negative (residual chlorine and pH) key factors influencing the THMs formation. This study conducts a deep understanding of water quality at the hydraulic junction areas and establishes predictive models for THMs formation in dual-sources DWDS.
Topics: Machine Learning; Water Quality; Drinking Water; Water Supply; Trihalomethanes; Models, Theoretical; Water Pollutants, Chemical; Chlorine
PubMed: 38368920
DOI: 10.1016/j.envres.2024.118474 -
Journal of Environmental and Public... 2019In Ethiopia, access to improved water supply and sanitation has been very low and hence majority of the communicable diseases are associated with unsafe and inadequate...
In Ethiopia, access to improved water supply and sanitation has been very low and hence majority of the communicable diseases are associated with unsafe and inadequate water supply. Thus, the aim of this study was to assess physicochemical and bacteriological characteristics of water from sources to household connection in Nekemte town. A cross-sectional study was conducted from November 2015 to March 2016. Water samples were collected in triplicates from selected 30 sampling points from source, disinfection point, main distribution system tank, and household taps. All samples were analysed for bacteriological, chemical, and physical quality parameters using standard procedures. The results showed that temperature, pH, turbidity, total dissolved substances, and electrical conductivity of the water samples were varied between 16.9 and 22°C, 6.8-7.0, nil-12 NTU, 50-70 mg/l, and 40-46 S/cm, respectively. Phosphate and nitrate concentrations of the water samples also ranged between 0.65 and 1 mg/l and 2.2-6.5 mg/l, respectively. Free residual chlorine concentration in the majority of the water samples was less than 0.5 mg/l. All samples were positive for total coliform with counts ranging from 12 to 120 CFU/100 ml, whereas faecal coliforms were detected in only 37% of tap water samples. In general, the majority of the tested parameters were within the permissible range of both the WHO and Ethiopian drinking water standards. However, Fe, Mn, faecal coliforms, total coliforms, and temperature did not conform to both WHO and Ethiopian drinking water standards. Based on the results, we can conclude that water quality deterioration was both at the sources and in the supply networks. Hence, proper drainage, sewage disposal systems, and sufficient disinfection of water with chlorine are of prime importance to deliver safe drinking water to the residents of Nekemte town.
Topics: Cross-Sectional Studies; Drinking Water; Electric Conductivity; Enterobacteriaceae; Environmental Monitoring; Ethiopia; Water Microbiology; Water Pollutants, Chemical; Water Quality; Water Supply
PubMed: 30906329
DOI: 10.1155/2019/2129792