Journal of water and health最新文献

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.

Deterioration of groundwater quality is an increasing global challenge threatening human health. This is highly exacerbated by the rapid urbanization mismatched with the planning of settlements and the provision of services. Many unplanned settlements are rapidly emerging with limited infrastructure for the management of environmental pollution sources. This has resulted in groundwater contaminations, which poses human health risks. This study was conducted to examine the risks associated with heavy metals (Pb, Cu, Cr, Cd and Zn) contamination in 75 boreholes used in 8 unplanned settlements of Dar es Salaam and the associated health risks. PerkingElmer, AAS-100 was used to analyze heavy metal concentrations in water samples. Risk assessment was established using the Hazard Quotient (HQ) and Chronic Daily Intake (CDI) using the United States Environmental Protection Agency (US EPA) Models. The results of CDI were in the order of Zn > Cr > Cu > Cd > Pb, and non-carcinogenic health risks were detected, particularly for Zn and Cr, with HQ > 1. The carcinogenic risks caused by cadmium and lead were above 1 × 10^-6 US EPA recommended standard. Pearson correlation indicated a weak to moderate correlation, indicating diversity of pollution sources. It is recommended to use alternative water sources for human consumption in the studied areas.

Three new probe-based quantitative PCR assays were designed based on existing PCR assays to quantitate Mycobacterium tuberculosis complex (MTBC) species, M. tuberculosis (MTB), and M. bovis (MB) in wastewater targeting genomic regions rv0577, RD9, and the deletion of RD4, respectively. The assays were validated for specificity using four Mycobacterial species, including two MTBC species and two non-tuberculosis Mycobacteria species, and endogenous wastewater samples from Ottawa, Ontario, Canada, Mumbai, India, and a remote Northern Indigenous community in Nunangat with known ongoing tuberculosis cases or outbreaks. The three assays demonstrate high sensitivity and are suitable for use in wastewater. Partitioning experiments performed on endogenous MTBC and MTB in collected wastewaters from Mumbai, India with known tuberculosis outbreaks show that the targeted genomic regions of rv0577 (MTBC) and RD9 (MTB) used to quantitate human tuberculosis infection predominately partition to solids fraction of wastewaters. The partitioning results of this study, in combination with the presented probe-based PCR assays, provide guidance on how to best enrich wastewaters and rapidly and economically quantify tuberculosis with high specificity and sensitivity in wastewaters.

Climate change (CC) is altering the working conditions for water suppliers. To enhance preparedness, CC has been emphasised in the risk-based approach (RBA) and water safety planning guidelines. We studied how the RBA approach has been applied in small water supplies in the Nordic countries to mitigate CC related risks and impacts. We interviewed small water supply operators and authorities in each country, followed up by government-level queries on guidelines and legislation. We found that small water supplies have experienced consequential incidents associated with a changing climate. Heavy rains, drought, changes in cold climate hydrology, and landslides were most frequently mentioned. Many of the supplies, however, had not experienced any effects, possibly because groundwater is the main water source for small water supplies in the region. Importantly, the effects of a changing climate were scarcely discussed, and CC receives limited or no attention in governmental guidelines. However, in Norway, the CC preparedness was analysed on a municipal level, and Finland and Sweden have tools for CC preparedness, but separately from the RBA. Small suppliers are concerned about over-burdening with multiple guidelines, frameworks, and tools. Therefore, we conclude that CC would be best addressed through integration into RBA and water safety planning regulation and implementation.

In light of the deterioration of microbiological composition of natural and technical water, the development of new approaches to its disinfection is an important technological task. The use of chlorine-active compounds remains the most effective for this purpose, but traditional preparations such as sodium hypochlorite pose a number of environmental risks. This paper describes the processes of treating model microbiologically contaminated solutions with granular styrene-divinylbenzene polymers with immobilized N-chlorosulfonamide groups. In this case, chlorine is released from the polymer surface into the solution due to chlorination of the amine components of the microbial cell. The amount of chlorine released is proportional to the degree of microbial contamination. The main factors influencing the disinfection rate and the characteristics of the chlorine emission process are the intensity of stirring, the type and concentration of the microorganism, and the surface area of the polymer. The treatment is effective against individual Gram-positive and Gram-negative bacteria, including multi-resistant ones, fungi, and multi-culture natural media. The use of this method for water disinfection potentially allows avoiding chlorine overdose, minimizing the formation of toxic chlorine-containing by-products, and ensuring long-term protection of water from re-contamination during storage.

This study evaluated the quality of tap water from surface and groundwater sources in rural and urban communities during the rainy and dry seasons and its implications for public health in Peru. Water samples were collected and physicochemical parameters and bacteriological indicators were determined. The Wilcoxon (W) test indicated that pH, electrical conductivity (EC), total dissolved solids (TDS), total hardness (TH) and chlorides (Cl^-) did not exceed permissible limits. In the rainy season, tap water from groundwater sources in rural communities presented the highest alkalinity values (326.67 mg CaCO₃/L), and those of Escherichia coli exceeded the permissible limit. The Kruskal-Wallis (KW) test evidenced significant differences in the physicochemical parameters of surface water according to the geographic zone. Correlations between physicochemical and bacteriological parameters ranged from weak to moderate. The water quality index revealed that 89% of the water samples in rural communities were classified as poor and very poor quality water, and 73% of the water samples in urban communities as good quality. These findings highlight the importance of implementing urgent measures to improve tap water quality to safeguard public health.

The release of untreated sewage from failing wastewater systems occurs globally, exposing residents to a range of negative physical and mental health outcomes. These circumstances might be particularly prevalent in underserved populations that often have inadequate infrastructure due to structural disinvestment. These communities face scenarios of persistent exposure to raw sewage in their homes, often containing waterborne pathogens and antibiotic-resistant (AR) bacteria. While most studies focus on understanding sanitary sewer overflows (SSOs) and backups at the watershed scale, we provide a transdisciplinary and comprehensive approach that assesses SSOs and basement backups, including social aspects, infrastructure burdens, and pathways of AR bacteria at the household level. Through our 40 home pilot studies, we implemented this study in Baltimore, Maryland (2022). We developed a five-step environmental sampling and community-driven methodology that combines urban planning, engineering, and public health, including (1) resident survey, (2) visual household inspection, (3) environmental sample collection and processing, (4) household and microbiological lab analysis, and (5) sharing results with participants. Our current efforts have utilized this framework to expand into three counties in Maryland. This study highlights the need to explore the impact of the built environment on public health and potential solutions to SSOs in underserved communities.

The threat of healthcare-associated infections is significantly heightened when caused by drug-resistant pathogens. This study evaluates water management practices and prevalence of antibiotic-resistant Pseudomonas aeruginosa in water systems of two tertiary hospitals of Ethiopia. We employed a mixed-methods approach, combining the qualitative data thematic analysis with quantitative microbiological results from 120 potable water samples. P. aeruginosa isolates were identified and subjected to antimicrobial susceptibility testing. Data collection was conducted between December 2023 and January 2024. The findings indicate that neither hospital had a dedicated water management programme for preventive maintenance. Microbial analysis revealed a 16% prevalence of P. aeruginosa in the water samples, with 26.3% of isolates demonstrating resistant to at least one antibiotic class. Notably, two isolates from the maternity ward of Hospital A exhibited multidrug resistance (MDR) to ciprofloxacin, amikacin, and imipenem. Overall, the structural and operational standard of the water management programmes in both hospitals were found to be non-conformant to international standards. A higher rate of Pseudomonas positivity, including resistant and MDR strains, indicates persistent hospital water contamination and a tangible risk for HAIs. These results underscore the critical need for the formation of multidisciplinary water safety team to optimize water quality management in these hospitals.

This study characterizes vancomycin-resistant Enterococci (VRE) in Iran's Anzali Lagoon recreational waters through analysis of 268 samples collected seasonally (2019). Culture and PCR methods identified Enterococcus in 57.5% (154/268) of samples, with 40.3% (62/154) showing vancomycin resistance. Resistance gene profiling revealed vanA and vanH predominance (56.5% each, 35/62), demonstrating complete co-occurrence, while vanB was rare (3.2%, 2/62) and vanC absent. Virulence factors displayed divergent prevalence: esp (62.9%, 39/62) exceeded clinical isolate rates, whereas hyl (3.2%, 2/62) was uncommon. Biofilm assays showed VRE isolates formed significantly denser biofilms than susceptible strains (2.3-fold higher OD570, p < 0.001), with esp-positive isolates exhibiting the strongest biofilm production. These findings demonstrate that recreational waters harbor VRE populations with: (1) elevated esp prevalence suggesting environmental selection pressures, and (2) enhanced biofilm capacity promoting persistence. The 100% vanA-vanH co-occurrence and 62.9% esp frequency surpass WHO risk thresholds for recreational waters, indicating need for revised monitoring protocols. This study provides the first evidence of aquatic-specific VRE genotypes in the region and their potential public health impacts through resistance gene dissemination and waterborne exposure risks.