Journal of water and health最新文献

Human adenoviruses (AdVs) are non-enveloped viruses that cause respiratory, ocular, and gastrointestinal infections. Owing to the absence of commercialized antiviral drugs for AdV infection, the urgent prevention of infection by inactivating AdVs is pertinent to public health. Accordingly, to establish effective disinfection methods against AdVs, this study assessed and compared the virucidal efficacy of multiple virucidal agents, namely ozonated water (OW), povidone-iodine (PVPI), and ethanol (EtOH), against AdV type 40 in vitro. The AdV-inactivating activity of OW was influenced by ozone concentration and was adversely affected by the presence of proteins. PVPI demonstrated consistent virucidal activity across a concentration range of 0.025-0.050% and maintained its efficacy in the presence of proteins. EtOH showed time-dependent and limited concentration-dependent virucidal activity across a concentration range of 60-80% and maintained its effectiveness in the presence of proteins. Polymerase chain reaction analysis of the viral genome revealed that OW was the only agent among the three that induced AdV genome degradation. Therefore, the study findings indicate that if the properties of OW are comprehensively understood to ensure its appropriate use, OW can be applied as a useful virucidal agent against AdV as well as other virus-inactivating agents, such as PVPI and EtOH.

The contamination of coastal water with Shiga-toxin-producing Escherichia coli (STEC) and Enteropathogenic Escherichia coli (EPEC) poses a significant risk to human health as they are causing severe gastroenteritis diseases. This study focused on detecting Enterohaemorrhagic E. coli (EHEC) and STEC in coastal waters along the southern coastal belt in Sri Lanka. Water samples (n=66) from 22 sampling locations were collected, and the virulent genes, eae, stx1 and stx2, were selected for the screening of EHEC and STEC. Amplification was done through optimized PCR protocols. Further, the water quality was measured in terms of N-NO^-₃, N-NO^-₂, N-NH₃, Total Nitrogen, Total Phosphate and COD in selected locations following the APHA standard methods. The findings indicate the presence of EHEC and STEC in some locations of the southern coast belt, which are popular for tourism and recreational activities. STEC were detected at 45.45% of sampling locations in the southern coastal belt of Sri Lanka, while EHEC was detected at 54.54%. Further, the recorded water quality values for N-NO₃^-, N-NO₂^-, N-NH₃⁺, Total Nitrogen, Total Phosphate and COD ranged from 0.30 to 3.48 mg/L, 0 to 0.64 mg/L, 0.03 to 2.39 mg/L, 0.48 to 4.31mg/L, 0.06 to 3.17mg/L and 584 to 679mg/L, respectively.

This study assessed the accuracy, field suitability, and cost-effectiveness of colorimetric LAMP (c-LAMP) assays using six heating instruments: Electric Kettle, Water Bath, Heating Block, miniPCR, Thermocycler, and Genie® III. Bacteroides HF183 (HF183), SARS-CoV-2, and Aichi virus A (AiV-A) were tested using control materials and wastewater samples, comparing cLAMP with qPCR/RT-qPCR detection. qPCR/RT-qPCR reliably detected HF183 and AiV-A genetic fragments at dilutions as low as 1 × 10^-5 pg/μL, corresponding to 1.24 and 1.49 log₁₀ GC/reaction. cLAMP/RT-cLAMP detected these fragments at 1 × 10^-4 pg/μL (2.28 and 2.63 log₁₀ GC/reaction), though Electric Kettle, miniPCR, and Genie® III occasionally produced false negatives. RT-qPCR reliably detected SARS-CoV-2 fragments at 1 × 10⁰ GC/μL (1.86 log₁₀ GC/reaction), with cLAMP/RT-cLAMP performing similarly across most instruments except Thermocycler. No significant differences (p > 0.05) were observed among instruments, though inconsistencies appeared at lower concentrations. The findings offer valuable insights into heating instrument performance for cLAMP/RT-cLAMP assays, guiding their application in wastewater-based pathogen detection.

Periodic evaluation of particulate contaminants in raw/untreated water is integral to assessing risk, establishing treatment requirements, and ensuring drinking water safety. However, pathogenic microorganisms and other discrete particles (e.g., microplastics) are not typically monitored with any regularity. When monitoring is required, recommended, or proactively used to evaluate the adequacy of treatment or assess treatment needs, there is a need for guidance on how to collect data and use them to maximize return on investment. The potentially increasing variability in source water quality associated with climate change emphasizes the importance of knowing contaminant concentrations to effectively manage risks. This work presents a framework to guide the development of monitoring protocols for particulate contaminants in water and the integration of monitoring data and quantitative microbial risk assessment into treatment decisions. The protozoa monitoring and risk-based compliance approach of a drinking water utility in Canada is presented along with 7 years of data. Guidance for determining sampling frequencies and locations is provided. It is shown that Cryptosporidium monitoring may be insufficient to inform treatment needs when Giardia cysts are more abundant in source water. This work underscores the importance of revisiting and enhancing monitoring practices for effective treatment and public health protection.

Recycled glass offers a promising, cost-effective alternative to silica sand for water filtration. This study evaluated its performance in a gravity-driven flow system using three particle sizes: gravel (G), coarse sand (CS), and fine sand (FS). As expected, a tradeoff was observed between turbidity reduction and permeability. FS achieved the greatest turbidity reduction (96.6% in particulate filtration and 93.1% in environmental water filtration) and Escherichia coli log removal of 1 ± 0.2, but low permeability. Higher permeability but poor turbidity and E. coli removal was achieved using G. To balance these tradeoffs, a layered filtration system was used to improve permeability with effective turbidity reduction (96.9% in particulate filtration and 93.5% in environmental water filtration). Without coagulant treatment, the E. coli log removal was 0.27 ± 0.15; with coagulant pre-treatment, it increased to 2.5 ± 0.4 for the layered filtration system. These findings demonstrate that crushed recycled glass can be used as an effective filtration medium and the filtration system can be configured with different particle sizes and/or layers to meet application-specific requirements.

Despite the high concentrations of heavy metals (HMs) in the water bodies of northern Mexico, current monitoring efforts and regulations are insufficient. This is especially troubling, given the indigenous and vulnerable communities and the overall lack of public health information. To characterize exposure, we conducted an exhaustive review of HM studies in drinking water in northern Mexico. This information was used to estimate hazard quotient (HQ) and carcinogenic risk (CR) values by age for all of northern Mexico. In total, 316 concentrations of HMs were reported in 55 studies from 1975 to 2021, with concentration ranges of 0-11,100, 0-5,250, 0-350, 0-25, and 0-9,470 μg/L for arsenic, cadmium, chromium, mercury, and lead, respectively. The probable maximum concentrations (95th percentile) of metals in drinking water were 244.55, 10, 56, 1.68, and 90.35 μg/L for arsenic, cadmium, chromium, mercury, and lead, respectively. The HQ for all HMs ranged from 0.0011 to 404.62. Children younger than 2 years had an extremely high risk (HQ > 40) of presenting adverse health effects from arsenic consumption. Children younger than 6 years had the highest risk of developing cancer, with CR values from 2.24 × 10^-5 to 7.77 × 10^-1, emphasizing the need for continuous HM monitoring in northern Mexico.

Severe droughts (SDs) present a risk to public health, particularly in terms of the proliferation of waterborne diseases, such as diarrhea. Because of climate change, the frequency of SDs is likely to increase, potentially straining traditional water supply systems. An 11-year period of SDs in Northeast Brazil, which commenced in 2012, reduced the capacity of 153 drinking water reservoirs to a mere 6.7%, with 86% of water bodies exhibiting eutrophic characteristics. During this period, several water supply and public health measures were implemented. Those measures were associated with a reduction in the incidence of diarrhea hospitalizations during the entire SD period, with an average annual reduction of -4.9%. This assessment identifies potential adaptive measures to mitigate the impact of climate change on water-related human health, thus supporting the implementation of measures to protect against climate risks to public health.

This study focuses on the area around Chaohu Lake region, utilizing data from the 2021 national surface water quality monitoring stations and land use data from territorial surveys. Employing GIS spatial analysis, non-parametric tests, Spearman correlation analysis, and redundancy analysis (RDA), the research examines how land use types within different buffer zone scales affect water quality. The findings indicate: (1) The dominant land use types in the study area are cultivated land, construction land, and water areas. (2) Overall, water quality is better in the dry season than in the rainy season, with higher concentrations of CODMn and TP occurring in the rainy season, and higher concentrations of DO, NH₃-N, and TN in the dry season. (3) Cultivated land and construction land are positively correlated with all water quality indices, whereas forest lands and water areas generally exhibit a negative correlation. The correlation between grasslands and water quality indices alternates with changes in spatial scale. (4) Within a buffer zone of 3,000 m, land use has the greatest impact on water quality, making it the optimal scale for assessing the influence of land use on water quality indices in the area around Chaohu Lake region (93.35%).

The purpose of this study was to determine the feasibility of facility-level wastewater surveillance in the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in skilled nursing facility (SNF) wastewater using three concentration methods, as well as a proof-of-concept for antimicrobial resistance (AR) genes/organisms detection. Wastewater effluent samples were collected from an SNF over an 8-week period. Wastewater was concentrated using electronegative membrane filtration (enMF), polyethylene glycol precipitation, and Nanotrap^® magnetic virus particles (NP). Quantification of the genome copy concentration from SARS-CoV-2 and bovine respiratory syncytial virus (BRSV), a SARS-CoV-2 surrogate spiked into all samples, was performed with droplet digital polymerase chain reaction (ddPCR). Wastewater sample aliquots were also enriched in microbiological culture media and screened for organisms with AR phenotypes on selective and differential agars. Multiplex real-time PCR was used to detect a broad array of carbapenem resistance genes. SARS-CoV-2 was detected and quantified from a single enMF-concentrated wastewater sample. The highest concentration of BRSV came from enMF-concentrated samples. Klebsiella, Enterobacter, Citrobacter, and Escherichia coli exhibiting AR phenotypes were successfully detected using culture-dependent approaches. Culture-independent, multiplex PCR indicated that bla_KPC was the main carbapenemase gene detected in wastewater samples. Facility-level wastewater surveillance could be a useful strategy for SNFs.

This study aims to identify important well characteristics associated with increased odds of bacterial contamination in the Wellington-Dufferin-Guelph public health unit of Southern Ontario. Identifying risk factors associated with bacterial contamination can aid in the mandate of public health units to promote the safety, and facilitate the testing, of drinking water systems to help minimize the risk of illness. Logistic regression models for adverse bacterial test results based on physical well characteristics were created. Models with the lowest Akaike Information Criterion values were examined for consistently identified characteristics. The odds of bacterial contamination in the Wellington-Dufferin-Guelph region are most associated with the age of the well, the season of testing, having a treatment system on the well, and the presence of potential point contamination sources within 50 feet (15.24 m) of the well. While this information can support the design of targeted public health education campaigns, the current model leaves room for improvement, as the predictive abilities of the models based solely on well characteristic data are limited.