Journal of water and health最新文献

Conventional water quality indices (WQIs), such as the Canadian Council of Ministers of the Environment Water Quality Index (CCME-WQI), typically assign equal weights to all parameters - a practice that may obscure the health relevance of pollutants with chronic toxicity. This study proposes a health risk-weighted variant of the CCME-WQI that integrates multivariate statistical analysis and toxicological criteria to enhance public health responsiveness. Using long-term monitoring data from the Dajia River Basin in Taichung, Taiwan (2003-2024), 30 physical and chemical parameters were analyzed using principal component analysis and factor analysis to reduce redundancy and identify key indicators. Ten core parameters were selected based on statistical contribution and health risk thresholds, including hazard quotient (HQ > 1), cancer risk (CR > 10^-4), and IARC classifications. Risk-based weights were assigned accordingly. Seasonal validation showed strong agreement between the optimized and original CCME-WQI models (RMSE = 7.72; p = 0.610), while improving sensitivity to high-risk contaminants such as arsenic, lead, and cadmium, particularly for children. The proposed framework offers a scalable and resource-efficient tool, making it suitable for both centralized and decentralized water quality management contexts, while supporting health-informed monitoring and contributing to Sustainable Development Goal 6.

In Indonesia and many urban areas, the coexistence of on-site sanitation and groundwater supply poses faecal contamination risks. Indonesian standards recommend a minimum 10-m horizontal separation and 2-m groundwater depth for siting sanitation systems. This study evaluated the effectiveness of these criteria in Metro City by mapping wells and sanitation systems, controlling for other risk factors, and repeat measurements of groundwater depth and well contamination. E. coli was detected in 70% of wells, with a median concentration of positive samples of 47 MPN/100 mL (interquartile range 6 -727 MPN/100 mL). Although 60% of wells were within 10-m of a sanitation system, horizontal separation was not significantly associated with contamination. Shallower groundwater was significantly associated with an increased presence and high concentrations of E. coli. The 2-m threshold was associated with high contamination but not E. coli presence. Water quality and groundwater depth varied over the 2-month dry season sampling period, and associations with risk factors varied between repeat and single sample analyses. Other factors also contributed to contamination, including uncovered wells, presence of livestock and rainfall. The findings highlight the limitations of standardised siting criteria, suggesting that site-specific risk assessments may be more effective in managing water and sanitation risks.

Rapidly assessing the viability of Mycobacterium species in drinking water and reuse systems is critical, as these pathogens pose significant monitoring challenges and health risks. Traditional culture methods are slow and biased, often failing to quantify viable but dormant/injured organisms' post-ultraviolet treatment. This study introduces a real-time reverse transcription polymerase chain reaction assay based on precursor ribosomal RNA (pre-rRNA) as a biomarker for bacterial viability. Brief nutritional stimulation detects low concentrations of metabolically active and dormant target pathogens, effectively distinguishing viable from dead organisms. Mycobacterium avium 104 in phosphate-buffered saline suspensions treated with ultraviolet irradiation (254 nm) were assessed using this rapid molecular method. Strong correlations (r > 0.94) with traditional culture-based assessment were observed. It reliably determined log reductions in pre-rRNA of stimulated samples relative to disinfectant dose within a day, significantly faster than the 12-14 days required for culture methods. An inactivation rate constant for M. avium 104 was established, along with a conversion factor (2.75) to convert pre-rRNA to bacterial log reduction. This pre-rRNA assay with nutritional stimulation is promising for rapid and reliable quantification of low concentrations of viable mycobacteria. It can significantly enhance water quality monitoring, accelerate disinfection technology evaluation, and improve public health risk assessment.

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.