Journal of water and health最新文献

The adsorption of trihalomethanes (THMs) from drinking water was investigated in the current study through comparison studies of kaolinite and ZnO@kaolinite nanocomposites. The clay structural network's successful immobilization on the zincite hexagonal structure of ZnO nanoparticles' lattice layers was verified by the SEM/EDX analysis. Under the optimum conditions, the maximum removal of THMs was achieved by kaolinite and ZnO@kaolinite nanocomposites after 60 min. The adsorption performance of the ZnO@kaolinite nanocomposites was greater than that of kaolinite because the former had a larger surface area than the latter. The Freundlich isotherm model best matched the adsorption experimental data, which also reveals the existence of multilayer adsorption on a diverse surface with the greatest correlation (R² = 0.956 and 0.954, respectively) for both nanoadsorbents using the pseudo-first-order (PFO), pseudo-second-order (PSO), mixed 1, 2-order (MFSO), and intraparticle diffusion (IPD) models. The mechanism by which THMs in drinking water adsorb onto nanoadsorbents was examined. This revealed that both intraparticle and film diffusion were involved in the adsorption process. Kaolinite and ZnO@kaolinite nanocomposites can be used in water treatment to remove THMs due to their great recyclable and reusable properties, even after six cycles.

The detection of bacterial contamination in drinking water is essential for monitoring the spread of foodborne diseases. We developed a simple, portable, and low-cost method of mini most probable number (mini MPN) to semi-enumerate bacterial suspension in water as a drinking water analogue. In this study, there is no significant difference between mini MPN and the standard method, technique plate count (TPC), at 10 and 100 CFU/ml Klebsiella pneumoniae suspension with a P-value of 0.28. For the ease-of-use aspect of this method, we tested several variables to prove it can be mass-applied in society. The usage of a sterile-plastic pipette, sample inoculation conducted in a biosafety cabinet (BSC), the usage of a 3-month storage medium, and incubation temperature conducted at room temperature compared to aseptic standard laboratory technique showed P-value > 0.05. In a trial for this method, we used commercialized drinking water for bacterial enumeration and characterization. We found multi-drug resistant (MDR) Ralstonia insidiosa which was resistant to at least four antimicrobial classes, including aminoglycosides, penicillins, cephalosporin, and carbapenem. Vitek 2 Compact was used for bacterial identification and antimicrobial susceptibility testing. A virulence test in Omphisa fuscidentalis larvae showed R. insidiosa strain D had a low virulence.

The presence of the freshwater snail Oncomelania hupensis lindoensis in their habitats is influenced by abiotic environmental factors (nutrients, water salinity, and predators) that play a crucial role in maintaining snail survival. The objective of this study is to determine the relationship between environmental factors and the presence of O. hupensis lindoensis snails in the Napu Valley, one of the Schistosomiasis-endemic areas in Indonesia. Eight environmental factors were measured in three different habitats: a seepage, a ditch, and a pond. The study found O. hupensis lindoensis snails in all three habitats, with significant differences in their numbers (p < 0.05). The seepage habitat had the highest snail density (762.22 snails per m²) compared to the other habitats. Phosphorus levels were highest in the seepage habitat compared to the other habitats, while nitrogen levels were highest in the pond habitat. Pearson correlation analysis found a significant positive correlation between O. hupensis lindoensis snails and water salinity in the ditch habitat (p < 0.05). In addition to environmental factors, the presence of snails can also be influenced by other factors, such as the presence of snail predators, the presence of snail nutrients, and the population of snail host niche competitors.

The purpose of this study was to assess the levels of fluoride in drinking water and its health impact in Semema, Tigray, Ethiopia. Water samples were collected in February, March and April from three potential spring water sources, namely May Atkaru, May Sensela and May Liham. Each sample was analyzed for a variety of physicochemical parameters including fluoride using standard APHA procedures through double beam UV-Visible spectrophotometer, atomic absorption spectrophotometer and titrimetric methods. All the measured physicochemical parameters except hardness (345.78-368.35 mg/L) and alkalinity (231.3-354.6 mg/L) were recorded below the WHO permissible limit set for drinking water. The amount of fluoride in May Atkaru (4.00 mg/L) and May Sensela (3.89 mg/L) was significantly greater than the WHO permissible limit set for drinking water, 1.5 mg/L. Moreover, HQ > 1 from May Atkaru and May Sensela revealed the possibility of dental and skeletal fluorosis over extended exposure to fluoride irrespective of age and sex variations. This confirmed people in the area with mottled teeth are vulnerable to the excessive consumption of fluoride, which poses health risks. Therefore, it needs immediate interventions to minimize the debilitating effect of fluoride in drinking water by creating awareness among the community and policymakers to introduce low-cost defluoridation methods.

Household water treatment (HWT) is recommended when safe drinking water is limited. To understand determinants of HWT adoption, we conducted a cross-sectional survey with 650 households across different regions in Haiti. Data were collected on 71 demographic and psychosocial factors and 2 outcomes (self-reported and confirmed HWT use). Data were transformed into 169 possible determinants of adoption across nine categories. We assessed determinants using logistic regression and, as machine learning methods are increasingly used, random forest analyses. Overall, 376 (58%) respondents self-reported treating or purchasing water, and 123 (19%) respondents had residual chlorine in stored household water. Both logistic regression and machine learning analyses had high accuracy (area under the receiver operating characteristic curve (AUC): 0.77-0.82), and the strongest determinants in models were in the demographics and socioeconomics, risk belief, and WASH practice categories. Determinants that can be influenced inform HWT promotion in Haiti. It is recommended to increase access to HWT products, provide cash and education on water treatment to emergency-impacted populations, and focus future surveys on known determinants of adoption. We found both regression and machine learning methods need informed, thoughtful, and trained analysts to ensure meaningful results and discuss the benefits/drawbacks of analysis methods herein.

Coastal water quality is facing increasing threats due to human activities. Their contamination by sewage discharges poses significant risks to the environment and public health. We aimed to investigate the presence of antibiotic-resistant Enterococcus in beach waters. Over a 10-month period, samples were collected from four beaches in the State of São Paulo (Brazil). Enterococcus isolates underwent matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) and molecular analysis for accurate genus and species identification. The antimicrobial susceptibility for 14 antibiotics was evaluated using the disc diffusion method followed by a multidrug-resistance (MDR) classification. PCR amplification method was used to detect antimicrobial resistance genes (ARGs). Our findings revealed the prevalence of Enterococcus faecalis, E. faecium and E. hirae. Out of 130 isolates, 118 were resistant to multiple antibiotics. The detection of resistance genes provided evidence of the potential transfer of antibiotic resistance within the environment. Our findings underscore the necessity for continuous research and surveillance to enhance understanding of the pathogenicity and antimicrobial resistance mechanisms of Enterococcus, which is crucial to implement effective measures to preserve the integrity of coastal ecosystems.

Outdoor decorative fountains usually attract residents to visit. However, opportunistic pathogens (OPs) can proliferate and grow in the stagnant fountain water, posing potential health risks to visitors due to the inhalation of spaying aerosols. In this study, the abundance of selected OPs and associated microbial communities in three large outdoor decorative fountain waters were investigated using quantitative PCR and 16S rRNA sequencing. The results indicated that Mycobacteria avium and Pseudomonas aeruginosa were consistently detected in all decorative fountain waters throughout the year. Redundancy analysis showed that OPs abundance was negatively correlated with water temperature but positively correlated with nutrient concentrations. The gene copy numbers of M. avium varied between 2.4 and 3.9 log₁₀ (gene copies/mL), which were significantly lower than P. aeruginosa by several orders of magnitude, reaching 6.5-7.1 log₁₀ (gene copies/mL) during winter. The analysis of taxonomic composition and prediction of functional potential also revealed pathogenic microorganisms and infectious disease metabolic pathways associated with microbial communities in different decorative fountain waters. This study provided a deeper understanding of the pathogenic conditions of the outdoor decorative fountain water, and future works should focus on accurately assessing the health risks posed by OPs in aerosols.

Escherichia coli is widely used as an indicator of recent faecal pollution of water. Most E. coli strains are commensals; however, isolates in water samples have been shown to carry antibiotic resistance determinants. In total, 47 E. coli were isolated from selected drinking water sources in Mbarara, Uganda. The isolates were examined for their susceptibility to seven antibiotics and the presence of nine antibiotic-resistance genes (mostly β-lactamase genes) and class 1 integrons. Isolates showed a high resistance to ampicillin of 55.5% and a high sensitivity to azithromycin and gentamicin at 98 and 96%, respectively. PCR analysis showed the presence of extended-spectrum β-lactamase genes bla_CTX-M-32 and bla_CMY-2 in 64 and 36% of the isolates. The carbapenemase genes bla_OXA-48, bla_VIM-2, bla_NDM-1, and bla_KPC-3 were either not detected or only in a very small number of the isolates, whereas class 1 integrons were present in 68% of the isolates. This study proves that antimicrobial resistance exists in E. coli in water used for drinking purposes in Mbarara city. There is a need for public health actors to improve the surveillance of microbiological quality of drinking water to minimize health risks.

Wastewater-based epidemiology (WBE) has emerged as a valuable tool for COVID-19 monitoring, especially as the frequency of clinical testing diminishes. Beyond COronaVIrus Disease 19 (COVID-19), the tool's versatility extends to addressing various public health concerns, including antibiotic resistance and drug consumption. However, the complexity of sewage systems introduces noise when measuring chemical tracer concentrations, potentially compromising their applicability for modeling. In our study, we detail the approach adopted to determine the concentration of severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) ribonucleiec acid (RNA) in wastewater from the Ponte a Niccheri wastewater treatment plant in Tuscany (Italy), with a sample size of N = 13,935 inhabitants. The unique characteristics of this wastewater system, including mandatory pretreatment in septic tanks with extended retention times, the presence of a hospital for COVID-19 patients, and mixed sewage networks, posed additional challenges. Nevertheless, our results highlight a robust and significant correlation between our measurements and the number of infections within the wastewater treatment plant's catchment area at the time of sampling. A simple linear model also shows promising results in estimating the number of infected people within the area.