Antibiotic resistance genes (ARGs) are present in surface water and often cannot be completely eliminated by drinking water treatment plants (DWTPs). Improper elimination of the ARG-harboring ...microorganisms contaminates the water supply and would lead to animal and human disease. Therefore, it is of utmost importance to determine the most effective ways by which DWTPs can eliminate ARGs. Here, we tested water samples from two DWTPs and distribution systems and detected the presence of 285 ARGs, 8 transposases, and intI-1 by utilizing high-throughput qPCR. The prevalence of ARGs differed in the two DWTPs, one of which employed conventional water treatments while the other had advanced treatment processes. The relative abundance of ARGs increased significantly after the treatment with biological activated carbon (BAC), raising the number of detected ARGs from 76 to 150. Furthermore, the final chlorination step enhanced the relative abundance of ARGs in the finished water generated from both DWTPs. The total enrichment of ARGs varied from 6.4-to 109.2-fold in tap water compared to finished water, among which beta-lactam resistance genes displayed the highest enrichment. Six transposase genes were detected in tap water samples, with the transposase gene TnpA-04 showing the greatest enrichment (up to 124.9-fold). We observed significant positive correlations between ARGs and mobile genetic elements (MGEs) during the distribution systems, indicating that transposases and intI-1 may contribute to antibiotic resistance in drinking water. To our knowledge, this is the first study to investigate the diversity and abundance of ARGs in drinking water treatment systems utilizing high-throughput qPCR techniques in China.
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•A total of 285 antibiotic resistance genes in drinking water treatment systems was investigated.•The drinking water treatment systems can affect the propagation of antibiotic resistance genes.•Positive correlations between ARGs and MGEs were observed during the distribution systems.
ARGs increased after BAC or chlorination in DWTPs and significant positive correlations between ARGs and MGEs during the distribution systems were observed.
The United States Environmental Protection Agency (USEPA) completed nationwide screening of six perfluoroalkyl substances in U.S. drinking water from 2013 to 2015 under the Third Unregulated ...Contaminant Monitoring Rule (UCMR3). UCMR3 efforts yielded a dataset of 36,139 samples containing analytical results from >5000 public water systems (PWSs). This study used UCMR3 data to investigate three aspects of per- and polyfluoroalkyl substances (PFASs) in drinking water: the occurrence of PFAS and co-contaminant mixtures, trends in PFAS detections relative to PWS characteristics and potential release types, and temporal trends in PFAS occurrence. This was achieved through bivariate and multivariate analyses including categorical analysis, concentration ratios, and hierarchical cluster analysis. Approximately 50% of samples with PFAS detections contained ≥2 PFASs, and 72% of detections occurred in groundwater. Large PWSs (>10,000 customers) were 5.6 times more likely than small PWSs (≤10,000 customers) to exhibit PFAS detections; however, when detected, median total PFAS concentrations were higher in small PWSs (0.12 μg/L) than in large (0.053 μg/L). Bivariate and multivariate analyses of PFAS composition suggested PWSs reflect impacts due to firefighting foam use and WWTP effluent as compared to other source types for which data were available. Mann-Kendall analysis of quarterly total PFAS detection rates indicated an increasing trend over time (p = 0.03). UCMR3 data provide a foundation for tiered design of targeted sampling and analysis plans to address remaining knowledge gaps in the sources, composition, and concentrations of PFASs in U.S. drinking water.
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•Analysis of data from nearly 37,000 drinking water samples collected in the U.S. and analyzed for per- and polyfluoroalkyl substances (PFASs).•Samples nationwide contain measureable levels of PFAS mixtures and other co-contaminants such as 1,4-Dioxane.•Data highlight a need for additional, targeted evaluation of small public water systems, private wells, and occurrence of a broader suite PFASs.
PFASs occur in public water systems throughout the U.S.; concentrations and composition are dominated by mixtures of PFASs and other co-contaminants.
The microbiological content of drinking water traditionally is determined by employing culture-dependent methods that are unable to detect all microorganisms, especially those that are not ...culturable. High-throughput sequencing now makes it possible to determine the microbiome of drinking water. Thus, the natural microbiota of water and water distribution systems can now be determined more accurately and analyzed in significantly greater detail, providing comprehensive understanding of the microbial community of drinking water applicable to public health. In this study, shotgun metagenomic analysis was performed to determine the microbiological content of drinking water and to provide a preliminary assessment of tap, drinking fountain, sparkling natural mineral, and non-mineral bottled water. Predominant bacterial species detected were members of the phyla Actinobacteria and Proteobacteria, notably the genera Alishewanella, Salmonella, and Propionibacterium in non-carbonated non-mineral bottled water, Methyloversatilis and Methylibium in sparkling natural mineral water, and Mycobacterium and Afipia in tap and drinking fountain water. Fecal indicator bacteria, i.e., Escherichia coli or enterococci, were not detected in any samples examined in this study. Bacteriophages and DNA encoding a few virulence-associated factors were detected but determined to be present only at low abundance. Antibiotic resistance markers were detected only at abundance values below our threshold of confidence. DNA of opportunistic plant and animal pathogens was identified in some samples and these included bacteria (Mycobacterium spp.), protozoa (Acanthamoeba mauritaniensis and Acanthamoeba palestinensis), and fungi (Melampsora pinitorqua and Chryosporium queenslandicum). Archaeal DNA (Candidatus Nitrosoarchaeum) was detected only in sparkling natural mineral water. This preliminary study reports the complete microbiome (bacteria, viruses, fungi, and protists) of selected types of drinking water employing whole-genome high-throughput sequencing and bioinformatics. Investigation into activity and function of the organisms detected is in progress.
•A multiresidue method was developed to trace micropollutants in drinking water.•A field study from source to tap detected a range of organic micropollutants at each sampling point.•Conventional ...drinking water treatment was found inefficient for many micropollutants.
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A multi-residue screening method for simultaneous measurement of a wide range of micropollutants in drinking water (DW) resources was developed. The method was applied in a field study in central Sweden on water from source to tap, including samples of surface water (upstream and downstream of a wastewater treatment plant, WWTP), intake water before and after a DW treatment plant (DWTP, pilot and full-scale), treated DW leaving the plant and tap water at end users. Low detection limits (low ng L−1 levels) were achieved by using large sample volumes (5 L) combined with ultra performance liquid chromatography high resolution mass spectrometry (UPLC-HRMS). In total, 134 different micropollutants were analyzed, including pesticides, pharmaceuticals and personal care products (PPCPs), drug-related compounds, food additives, and perfluoroalkyl substances (PFASs). Of these 134 micropollutants, 41 were detected in at least one sample, with individual concentrations ranging from sub ng L−1 levels to ~80 ng L−1. Two solid phase extraction (SPE) cartridges (Oasis HLB and Bond-Elut ENV) were shown to be complementary in the field study, with three compounds detected exclusively using HLB. The total concentration in treated drinking water (56–57 ng L−1) was at a similar level as upstream from the WWTP (79–90 ng L−1). The composition of micropollutants changed along the water path, to a higher fraction of food additives and PFASs. Median treatment efficiency in the full-scale DWTP was close to 0%, but with high variability for individual compounds. In contrast, median treatment efficiency in the pilot-scale DWTP was ~90% when using nanofiltration followed by a freshly installed granulated active carbon (GAC) filter.
Coastal areas in Southeast Asia are experiencing high sodium concentrations in drinking water sources that are commonly consumed by local populations. Salinity problems caused by episodic cyclones ...and subsequent seawater inundations are likely (partly) related to climate change and further exacerbated by changes in upstream river flow and local land-use activities. Dietary (food) sodium plays an important role in the global burden of hypertensive disease. It remains unknown, however, if sodium in drinking water-rather than food-has similar effects on blood pressure and disease risk. In this study, we examined the effect of drinking water sodium on blood pressure of pregnant women: increases in blood pressure in this group could severely affect maternal and fetal health. Data on blood pressure, drinking water source, and personal, lifestyle, and environmental confounders was obtained from 701 normotensive pregnant women residing in coastal Bangladesh. Generalized linear mixed regression models were used to investigate association of systolic and diastolic blood pressure of these-otherwise healthy-women with their water source. After adjustment for confounders, drinkers of tube well and pond water (high saline sources) were found to have significantly higher average systolic (+4.85 and +3.62 mm Hg) and diastolic (+2.30 and +1.72 mm Hg) blood pressures than rainwater drinkers. Drinking water salinity problems are expected to exacerbate in the future, putting millions of coastal people-including pregnant women-at increased risk of hypertension and associated diseases. There is an urgent need to further explore the health risks associated to this understudied environmental health problem and feasibility of possible adaptation strategies.
This study investigated the photocatalytic degradation of RB dye by Vsub.2Osub.5@g-Csub.3Nsub.4 nano-catalysts. The sonication method was utilized to create Vsub.2Osub.5@g-Csub.3Nsub.4 ...nano-catalysts. Vsub.2Osub.5@g-Csub.3Nsub.4 nano-catalysts were characterized using X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), high-resolution electron microscopy (TEM), BET-surface area analyzer, X-ray photoelectron spectroscopy (XPS), and ultraviolet spectroscopy. In the meantime, the photocatalytic activity, pH, and photocatalyst dosage are investigated in depth to account for RB dye decolorization. The rate constant for RB dye photodegradation was 0.0517 (minsup.−1) and the decolorization rate was 93.4%. The degrading efficiency of RB dye by Vsub.2Osub.5@g-Csub.3Nsub.4 nanocatalysts is consistent with pseudo-first-order kinetics. The results of this study demonstrated that Vsub.2Osub.5@g-Csub.3Nsub.4 nanocatalysts are particularly effective at destroying dyes in water.
This study applied a sensitive dansylation LC-MS/MS method to the investigation on the occurrence of bisphenol A (BPA), nonylphenol (NP), estrogens (E1 and E2), and their 11 chlorinated byproducts in ...62 drinking water treatment plants (DWTPs) of 31 major cities across China. BPA (4.7–512 ng/L), NP (8.2–918 ng/L), and E1 (ND-9.9 ng/L) were widely detected in source waters, E2 was detected in less than half of the samples (ND-3.2 ng/L), while chlorinated byproducts were only detected in source waters of two DWTPs. In drinking water, chlorinated BPAs and monochloro-NP (MCNP) were detected in more than half of the samples with concentrations of 0.2–26.7 ng/L for monochloro-BPA (MCBPA), ND-6.3 ng/L for dichloro-BPA (DCBPA), ND-7.7 ng/L for trichloro-BPA (TCBPA), ND-4.8 ng/L for tetrachloro-BPA (TBBPA), and ND-13.3 ng/L for MCNP, while dichloro-E1 (DCE1, ND-0.2 ng/L) and dichloro-NP (DCNP, ND-1.6 ng/L) were less frequently detected (10/62 and 4/62). The production of chlorinated NPs in DWTPs was mainly influenced by the amount of NP in source water and chlorine added, while the concentrations of chlorinated BPAs in drinking waters were only found to be significantly correlated with those of BPA in source waters. Advanced treatment processes could be effective techniques for reducing target chlorinated byproducts in drinking water. This is the first report on the occurrence of chlorinated byproducts of BPA, NP, and estrogens in drinking water, and these chemicals should be considered when assessing the human risk of their parent compounds.
To date, experimental and epidemiological evidence of endocrine disrupting compounds (EDCs) adversely affecting human and animal populations has been widely debated. Notably, human health risk ...assessment is required for risk mitigation. The lack of human health risk assessment and management may thus unreliably regulate the quality of water resources and efficiency of treatment processes. Therefore, drinking water supply systems (DWSSs) may be still unwarranted in assuring safe access to potable drinking water. Drinking water supply, such as tap water, is an additional and crucial route of human exposure to the health risks associated with EDCs. A holistic system, incorporating continuous research in DWSS monitoring and management using multi-barrier approach, is proposed as a preventive measure to reduce human exposure to the risks associated with EDCs through drinking water consumption. The occurrence of EDCs in DWSSs and corresponding human health risk implications are analyzed using the Needs, Approaches, Benefits, and Challenges (NABC) method. Therefore, this review may act as a supportive tool in protecting human health and environmental quality from EDCs, which is essential for decision-making regarding environmental monitoring and management purposes. Subsequently, the public could have sustainable access to safer and more reliable drinking water.
•Presence of EDCs in global drinking water supplies is risky to public health.•Humans are potentially exposed to EDCs via drinking water consumption.•EDCs influence physiological functions of exposed individuals.•NABC analysis gives political/economic/social insights into safe drinking water.•A holistic approach is proposed to reduce human exposure to EDCs.
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