Journal of water and health最新文献

Unsafe and fecally contaminated water can act as a vehicle for the transmission of waterborne pathogens. The objective of this study was to evaluate the bacteriological quality of drinking water and hygienic practices among households. The study was conducted at selected sites in the Sekela district, Amhara, Ethiopia. A cross-sectional study was conducted from March to May 2021. A total of 90 water samples from seven different sources were collected and analyzed in the laboratory. Questionnaires were developed to collect information about sociodemographic background and hygienic practices. The numbers of total coliform (TC) and fecal coliform (FC) were counted using the membrane filtration method. Of 90 water samples collected for laboratory analysis, 86 (95.50%) samples were positive for TC bacteria, and 70 (81.40%) samples exhibited FC growth. There was no statistically significant difference (P > 0.05) between the bacterial count and water samples collected from different sources among the three sites. The majority of households practiced open-field defecation (67.50%), and they had no source of information about water-handling practices (92.50%). The coliform counts of sampled water from different sources were high, posing a public health concern. Health education on hygiene practices needs to be implemented for the communities.

Water, sanitation, and hygiene (WASH) practices are essential determinants of healthy living. Households lacking proper WASH conditions can experience a burden of various diseases. The primary aim of this study is to investigate the rural-urban differences in WASH conditions and disease burden in eastern India, a region of high under-five mortality. This study utilizes secondary data from the 76th round of National Sample Survey. Multivariable logistic regression is employed to examine the association between WASH practices and diseases. Additionally, Fairlie decomposition is utilized to comprehend the factors contributing to rural-urban disparities in the prevalence of diseases associated with WASH. The study found improper WASH practices to be associated with the prevalence of certain diseases. Rural households were likely to suffer more from diseases than urban households. Other than the WASH factors, the income factor played a major role in widening the rural-urban gap in disease prevalence. The study confirms the link between WASH conditions and specific diseases. It indicates a social gradient of diseases where rural, impoverished households are more susceptible to WASH-related illnesses. Therefore, the study suggests that greater attention must be devoted to improving WASH conditions in rural areas.

In rapidly developing urban communities, recreational water quality is often compromised by the presence of fecal pollution, increasing the potential risk to public health. In this study, surface water samples from tributaries to Lake Pontchartrain (an estuary in southeastern Louisiana, United States), recreational shoreline sites, and wastewater samples from residential aerobic treatment units (ATU) were collected and analyzed for fecal bacteria using both culture- and molecular-based assays. During the 2-year study period, fecal indicator bacteria (coliform, Escherichia coli, and enterococci) were detected in all water samples collected from tributaries. Human-specific fecal marker concentrations varied per sampling site but were significantly higher in tributaries, demonstrating individual wastewater treatment units as a primary source of fecal contamination. Pathogenic E. coli and Campylobacter jejuni were only detected in tributaries. Statistical analysis indicated weak relationships between physiochemical water quality parameters and concentrations of enteric pathogens or fecal markers. The prevalence of human fecal contamination in estuaries poses a potential public health problem for recreational use, as it increases exposure risks. This study demonstrates that the application of multiple water quality indicators may yield greater confidence in assessing fecal contamination and ultimately could better inform remediation decisions to improve recreational water quality.

Toxicity tests with marine luminescent bacteria, such as Vibrio fischeri, typically require a 2-3% NaCl adjustment to simulate marine environments. However, this addition may inadvertently promote bacterial growth, leading to an overestimation of toxicity. This study investigates the toxicity of lipopolysaccharides (LPS), components of the outer membrane of Gram-negative bacteria that pose significant health risks. We focused on the interaction between LPS and V. fischeri, assessing its bioluminescent response. Measuring LPS toxicity through bioluminescence inhibition necessitates careful consideration of how NaCl impacts bacterial growth and LPS toxicity. The effects of LPS on bioluminescence were studied in two solutions: 3% NaCl and photobacterium medium. Experiments utilized three injection volumes (25, 50, and 75 μL) and a range of LPS concentrations (1 × 10^-1 to 1 × 10^-10 mg/mL). Results demonstrated that the type of solution, LPS concentration, and injection volume significantly affected bioluminescence. The strongest inhibition was observed at a concentration of 1 × 10^-3 mg/mL in a photobacterium medium (74%) and 3% NaCl at a concentration of 1 × 10^-1 mg/mL (65%). The effective concentrations (EC₅₀) revealed the highest toxicity in the photobacterium medium (EC₅₀ = 3.08 × 10^-5 mg/mL at 50 μL) compared to 3% NaCl (EC₅₀ = 0.0003 mg/mL at 25 μL).

Despite significant advancements in water treatment, waterborne disease outbreaks are being reported from across the globe. A total of 29 source and treated water samples from the two drinking water treatment plants (DWTPs), and 32 influent and effluent water samples from the municipal wastewater treatment plant (WWTP) were collected in the city of Hamadan, Iran. In addition, eight municipal sewage samples were collected. The samples were concentrated by polyethylene glycol precipitation, and nucleic acids were extracted and assayed for Adv using standard PCR, nested PCR and real-time PCR targeting the hexon gene. More than half (55.1%) of the samples tested positive for AdV by at least one of the detection methods. In the WWTP, 63.6% of influent and 80% of effluent samples tested positive, indicating ineffective viral removal during the treatment process. Whereas, in the DWTPs, 50% of source and 28.6% of treated water samples tested positive, indicating a more effective viral removal by the DWTP. Among the molecular techniques employed, nested PCR demonstrated superior sensitivity. The study identifies the trend of adenovirus occurrence and the effective methods for determining their prevalence and the potential risk of viral exposure from the municipal water systems in the city of Hamadan, Iran.

Drinking water stored at home is often prone to fecal contamination in unplanned settlements. The present study investigated the transmission pathways of fecal contamination to stored tap water in peri-urban Lusaka, Zambia. Samples from stored tap water (n = 21), kitchenware (n = 50), floor surfaces (n = 80), and flies in living spaces (n = 304) were collected in October and November 2019 and tested for Escherichia coli. Path analysis showed two major transmission routes to stored tap water contamination: (1) from house-entrance floor to cups (path coefficient (β): 0.37) and then to stored tap water (β: 0.92), and (2) from flies at house entrance to flies inside kitchen (β: 0.78), then to cups (β: 0.57), and finally to stored tap water (β: 0.92). Cups were the key transmission medium, potentially contaminated from house entrances and by flies in the kitchen. The findings highlight the critical role of cup and floor cleaning and fly control in living spaces in protecting stored drinking water in poor water, sanitation, and hygiene environments.

While small-scale irrigation is largely designed and developed for agricultural production, irrigation water is used for multiple other purposes in rural low- and middle-income settings where dedicated water, sanitation, and hygiene services (WASH) are not available. Therefore, expanding access to irrigation can potentially improve the WASH environment leading to health and nutrition benefits. This study examines the linkages between irrigation, use of irrigation water sources for multiple purposes, and WASH and health outcomes. We find that irrigation is associated with better household access to water and improved sanitation facilities. This relationship is driven by households that use groundwater for both irrigation and domestic purposes. Moreover, our results show that hygiene practices and health outcomes are not influenced by irrigation or multiple uses of the same water source. To strengthen hygiene behavior, behavioral change communication will be important. For small-scale irrigation to effectively support WASH and, thus, to strengthen nutrition and health outcomes, systems would need to be co-designed by irrigation and health specialists.

Orthophosphate is a common corrosion inhibitor used to control lead release in drinking water distribution systems (DWDSs). It may enhance monochloramine decay and promote biofilm growth. This study assessed the impact of two monochloramine dosages on biofilm growth and monochloramine decay in model distribution systems (MDSs), with/without orthophosphate, at a 10-day residence time. Four bench-scale MDSs were run for 15 weeks: two tested a low monochloramine dose (2 mg Cl₂/L), with or without orthophosphate, and two a higher dose (3 mg Cl₂/L), with and without orthophosphate. The feedwater was phosphorus-limited, which may have amplified microbial response to orthophosphate addition. At both monochloramine dosages tested, orthophosphate addition increased viable cell count, biofilm reformation potential, and metabolic activity, while biofilm genetic diversity was influenced by both orthophosphate and monochloramine dose. Communities subjected to high monochloramine without orthophosphate were the least diverse, whereas those exposed to low monochloramine with orthophosphate showed the greatest diversity. These findings suggest that high monochloramine exerts selective pressure, reducing diversity, while orthophosphate enhances it. First-order total chlorine decay coefficients were higher in MDSs with lower monochloramine doses, and at the same dose, MDSs with orthophosphate showed slightly higher monochloramine decay than those without orthophosphate.

The presence of antibiotic resistant bacteria in three rivers with different basin characteristics focusing in particular on ampicillin (AMP)-resistant and extended-spectrum β-lactamase (ESBL)-producing bacteria were investigated. Antimicrobial-resistant Escherichia coli and other coliform groups were isolated from the upstream, midstream, downstream, and estuary sections of each river. Analyses of bacterial counts as well as of antimicrobial resistance profiles and ESBL-related gene groups/types were performed and the results were compared among river basins. In the Kaeda River, where approximately 90% of the catchment area is covered by forests, AMP-resistant E. coli had a low prevalence of only 1-2% from the midstream to the estuary. However, the prevalence of other coliforms showing AMP resistance in the Kaeda River basin was between 10 and 19%, which was 2-5 times higher than the prevalence in the upstream and midstream sections of the Yae River, where the abundance of other coliforms was still significantly high. The main ESBL-producing coliforms were Enterobacter bugandensis, Aeromonas hydrophila, and Stenotrophomonas maltophilia. To protect public health, it is essential to monitor the sources and fates of coliform species throughout entire watersheds, from headwaters to downstream reaches including urban areas, as they are of comparable importance to E. coli.

Private drinking water supplies (e.g. household wells) are non-regulated drinking water systems typically concentrated in rural areas. Previous research suggests that water quality issues in homes served by these systems are common, but limited efforts to link these issues to user sociodemographics render the design of interventions difficult. The work aims to link user demographics to the presence of in-home treatment for homes on private water supplies in Virginia. Between 2020 and 2024, water quality samples and paired surveys detailing user demographics were collected from six southwest Virginia counties. The most common contaminants observed, according to municipal health-based standards, were lead, copper, Escherichia coli, and coliform. Other common contaminants associated with water aesthetics and municipal guidance levels were aluminum, sodium, pH, iron, and manganese. Thirty-five percent of homes had no treatment device prior to consumption, while 43% only used aesthetic-based treatment devices. Forty-four percent of households with income <$52,000 indicated no treatment devices present, and 47% of homes with some or graduated high school education reported no treatment. Results support the hypothesis that households with lesser educational attainment and lower income are less likely to have access to treatment, which limits the system's ability to remove contaminants.