Search Results (777)

Due to the high uncertainty of model predictions, it is often challenging to draw definitive conclusions when evaluating river water quality in the context of management options. The major aim of this study is to present a statistical evaluation of the Hydrologic Simulation Program FORTRAN (HSPF), which is a water quality modeling system, and how this modeling system can be used as a valuable tool to enhance monitoring planning and reduce uncertainty in water quality predictions. The authors’ findings regarding the sensitivity analysis of the HSPF model in relation to water quality predictions are presented. The application of the computer model was focused on the Ave River watershed in Portugal. Calibration of the hydrology was performed at two stations over five years, starting from January 1990 and ending in December 1994. Following the calibration, the hydrology model was then validated for another five-year period, from January 1995 to December 1999. A comprehensive evaluation framework is proposed, which includes a two-step statistical evaluation based on commonly used hydrology criteria for model calibration and validation. To thoroughly assess model uncertainty and parameter sensitivity, a Monte Carlo method uncertainty evaluation approach is integrated, along with multi-parametric sensitivity analyses. The Monte Carlo simulation considers the probability distributions of fourteen HSPF water quality parameters, which are used as input factors. The parameters that had the greatest impact on the simulated in-stream fecal coliform concentrations were those that represented the first-order decay rate and the surface runoff mechanism, which effectively removed 90 percent of the fecal coliform from the pervious land surface. These parameters had a more significant influence compared to the accumulation and maximum storage rates. When it comes to the oxygen governing process, the parameters that showed the highest sensitivity were benthal oxygen demand and nitrification/denitrification rate. The insights that can be derived from this study play a critical role in the development of robust water management strategies, and their significance lies in their potential to contribute to the advancement of predictive models in the field of water resources. Full article

According to a report by the World Health Organization (WHO), each year, over 550 million individuals worldwide suffer from and 230,000 die from diarrheal illnesses, which accounts for more than half of the global foodborne disease burden. Among them, children face a heightened vulnerability, with approximately 220 million falling ill and 96,000 succumbing to these diseases annually. This work aimed to study the genomic characterization of selected E. coli strains from catfish (Clarias (C.) gariepinus) caught from the Onitsha North axis of the River Niger in Anambra state, Nigeria. A total of 50 fish were randomly purchased from different fishermen over a period of four months. Samples that comprised six different organs (skin, flesh, gills, gonads, guts, and liver) were screened for E. coli strains using cultural and biochemical methods. Multilocus sequence typing (MLST) and core genome (cg)MLST were performed using Ridom SeqSphere+ software. The aerobic plate count (APC) and coliform count ranged from 0.5 × 10⁴ to 3.7 × 10⁴ cfu/g and 0 to 3.0 × 10⁴ cfu/g, respectively. Whole-genome sequencing (WGS) confirmed the presence of E. coli and Klebsiella quasipneumoniae isolates in our samples. We could identify only two serotypes (O102:H7 and O40:H4) of E. coli. Antimicrobial resistance genes (ARGs) and point mutations that conferred antibiotic resistance were extracted from the genome assemblies. Good hygiene is recommended to avoid the cross-contamination of raw C. gariepinus with ready-to-eat food. Full article

Dimba Cave is a large array of natural galleries in limestone mountains of the Democratic Republic of the Congo that contains highly valued pre-historic archaeological artifacts. The cave attracts a high number of tourists every year and is used by local populations as a water supply source. The main objective of the research undertaken in Dimba Cave consisted of assessing the quality of water and sediments from Dimba Cave ponds through evaluating contamination by heavy metals (15 elements analyzed, including As, Cd, Pb, and Hg) and by microbial populations (including Escherichia coli and total coliforms) in order to estimate the ecotoxicological risk to humans and to non-human biota. All water samples collected in the cave ponds showed very high metal concentrations exceeding the internationally recommended limits for drinking water, particularly for Cr, Mn, As, Pb, and Hg. Most sediment samples from cave ponds also displayed high heavy metal concentrations. The calculated pollution parameters, such as the enrichment factor (EF), and ecological risk parameters, such as the ecological risk index (Eri), indicated that the sediment may be toxic to aquatic biota. Furthermore, the microbiological analysis of pond waters indicated a widespread contamination with bacteria such as Escherichia coli, Enterococcus spp., total coliforms, and Pseudomonas spp., probably from anthropogenic and/or animal sources. Therefore, the consumption of Dimba Cave water as a drinking water represents a threat to public health. Urgent management measures should be enforced to protect public health and the cave ecosystem. Full article

The World Health Organization (WHO) recommends the introduction of a water safety plan (WSP) approach on drinking water, in all types of settings. This study represents the first WSP developed on the Neptune Fountain, in Bologna (Italy), based on an interdisciplinary approach, integrating hydraulic and microbiological features, in a Building Information Modeling (BIM). The aim was to develop a dynamic and digital platform to update and share the maintenance program, promoting collaboration among microbiologists, engineers, and municipal staff. Water samples were collected along fountain water distribution systems (WDS) from 2016 to 2021 to monitor water quality through the heterotrophic bacteria at 22 °C and 37 °C, as well as to conduct an Enterococci, Coliform bacteria, Escherichia coli, Pseudomonas aeruginosa, Clostridium perfringens, and Staphylococcus aureus assessment. Simultaneously, hydraulic measures were performed, and advanced geomatics techniques were used to detect the WDS structural components, with a focus on the water treatment system (WTS). The WTS consisted of 10 modules corresponding to specific treatments: descaling, carbon–sand filtration, reverse osmosis, and ultraviolet disinfection. Fecal indicators, heterotrophic bacteria, and P. aeruginosa exceeded the reference limits in most of the modules. Several disinfections and washing treatments, other than changing the maintenance procedure scheduling, were performed, improving the WTS and controlling the contamination. The developed microbiological results, hydraulic measurements, and maintenance procedures were integrated in the BIM model to optimize the data storage, updating procedures and the real-time data sharing. This approach improved the fountain management, operation, and material conservation, ultimately preserving the health of daily visitors. Full article

The kelp gel edible granules developed utilizing the gel properties of alginate are prone to quality deterioration if improperly stored during the storage process. This study comprehensively investigated the quality changes of kelp gel edible granules stored at 4 °C and 25 °C by evaluating indicators such as total bacterial count, coliform bacteria, pH, relaxation time, color difference, appearance, texture characteristics, gel strength, and sensory scoring. The results showed that during the storage at 4 °C, the total bacterial count remained within the national standard range, the hardness and chewiness increased, the gel strength first increased and then decreased, the partial exudation of the bound water in the product occurred, and the sensory score slightly decreased, with an overall minor change in quality. During the storage at 25 °C, significant quality changes were observed, with the total bacterial count exceeding the national standard on the 20th day; additionally, the hardness, chewiness, and gel strength all initially increased and then decreased, both the bound water and the restrained water in the product exuded, the moisture stability decreased, and the sensory score significantly decreased between 16 to 20 days. The spoilage of the product was characterized by a significant water loss, reduction in volume, color change from bright green to dark yellow-brown, and a distinct smell of decaying algae. No coliform bacteria was detected in all products during the storage period. In summary, the shelf life endpoint of the product stored at 25 °C is 16 days, and the shelf life of the product stored at 4 °C is greater than 20 days. Storage at 4 °C can better maintain product quality, extend the shelf life, and effectively maintain the overall color of the product. Full article

The aim of this 2-year study was to evaluate the influence of bed depth (40 and 60 cm) on the development of tropical ornamental species (Alpinia purpurata, Heliconia latispatha and Strelitzia reginae) and on the removal of different contaminants such as chemical oxygen demand (COD), nitrate (N-NO₃), ammonium (N-NH₄), total nitrogen (TN), total phosphorus (TP), total suspended solids (TSS), total coliforms (TCs) and fecal coliforms (FCs), in horizontal subsurface flow constructed wetlands (HSSF-CWs) for municipal wastewater treatment. The results showed that the depth of 60 cm favored the removal of COD, with removal efficiencies of 94% for the three plant species. The depth of 40 cm was most effective for the removal of N-NH₄ (80–90%). Regarding the removal of TN, the removals were similar for the different plants and depths (72–86%). The systems only achieved up to 60% removal of TCs and FCs. The depth of the CWs substrate and its saturation level influenced the development of ornamental vegetation, particularly flower production. For Heliconia latispatha, a bed depth level of 60 cm was more suitable, while for Alpinia purpurata 40 cm was better, and for Strelitzia reginae in both cases there was no flower production. The impact of bed depth on contaminant removal depends on the specific type of contaminant. Full article

The consumption of Umqombothi alcoholic beverages in South Africa is widespread in townships and rural areas. This study aimed to investigate the effect of sorghum and maize malt particle size on the physicochemical, microbiological, stability, and sensory characteristics of Umqombothi. Three different particle sizes were compared, namely control, coarse, and fine powder particle sizes. Subsamples were taken at the following stages, during the production of Umqombothi: first, second, third, fourth, and fifth. Lactic acid bacteria were significantly dominant, with 8.16, 7.11, and 5.91 log cfu/mL in the final product for the control, coarse, and fine powder particle sizes. The yeast counts were 3.3, 4.64, and 5.63 log cfu/mL for the control, coarse, and fine powder particle sizes. Molds were significantly reduced to non-detectable levels after the second fermentation and the total coliforms in the final product were reduced for all particle sizes. The total soluble solids significantly decreased in the second fermentation samples. The coarse particle size exhibited significantly higher alcohol and significantly lower pH levels, which are encouraging signs for improved quality and shelf life. Different particle sizes of sorghum and maize malt affect the quality of the finished product and the production method of umqombothi. Full article

The prospect of drinking water serving as a conduit for gut bacteria, artificially selected by disinfection strategies and a lack of monitoring at the point of use, is concerning. Certain opportunistic pathogens, notably some nontuberculous mycobacteria (NTM), often exceed coliform bacteria levels in drinking water, posing safety risks. NTM and other microbiota resist chlorination and thrive in plumbing systems. When inhaled, opportunistic NTM can infect the lungs of immunocompromised or chronically ill patients and the elderly, primarily postmenopausal women. When ingested with drinking water, NTM often survive stomach acidity, reach the intestines, and migrate to other organs using immune cells as vehicles, potentially colonizing tumor tissue, including in breast cancer. The link between the microbiome and cancer is not new, yet the recognition of intratumoral microbiomes is a recent development. Breast cancer risk rises with age, and NTM infections have emerged as a concern among breast cancer patients. In addition to studies hinting at a potential association between chronic NTM infections and lung cancer, NTM have also been detected in breast tumors at levels higher than normal adjacent tissue. Evaluating the risks of continued ingestion of contaminated drinking water is paramount, especially given the ability of various bacteria to migrate from the gut to breast tissue via entero-mammary pathways. This underscores a pressing need to revise water safety monitoring guidelines and delve into hormonal factors, including addressing the disproportionate impact of NTM infections and breast cancer on women and examining the potential health risks posed by the cryptic and unchecked microbiota from drinking water. Full article

Urban wastewater is a significant by-product of human activities. Conventional urban wastewater treatment plants have limitations in their treatment, mainly concerning the low removal efficiency of conventional and emerging contaminants. Discharged wastewater also contains harmful microorganisms, posing risks to public health, especially by spreading antibiotic-resistant bacteria and genes. Therefore, this study assesses the potential of a native microalgae-bacteria system (MBS) for urban wastewater bioremediation and disinfection, targeting NH₄⁺-N and PO₄³⁻-P removal, coliform reduction, and antibiotic resistance gene mitigation. The MBS showed promising results, including a high specific growth rate (0.651 ± 0.155 d⁻¹) and a significant average removal rate of NH₄⁺-N and PO₄³⁻-P (9.05 ± 1.24 mg L⁻¹ d⁻¹ and 0.79 ± 0.06 mg L⁻¹ d⁻¹, respectively). Microalgae-induced pH increase rapidly reduces coliforms (r > 0.9), including Escherichia coli, within 3 to 6 days. Notably, the prevalence of intI1 and the antibiotic resistance genes sul1 and bla_TEM are significantly diminished, presenting the MBS as a sustainable approach for tertiary wastewater treatment to combat eutrophication and reduce waterborne disease risks and antibiotic resistance spread. Full article

This study implemented and assessed, over a period of four weeks, a full-scale constructed wetland designed to collect and treat the greywater for a rural household located in an arid environment typical of Africa’s Sahel region. The system was constructed from local materials and consisted of a shower room, a receiving basin, a pre-treatment filter, and a subsurface horizontal flow wetland planted with Chrysopogon zizanioides. Results showed the overall removal of organic matter was greater than 90%, and orthophosphate and ammonium were reduced by 73% and 60%, respectively, allowing for the treated water to retain some embedded nutrients. The removal efficiency of fecal bacteria varied from 3.41 (enterococci) to 4.19 (fecal coliforms) log10 units which meets World Health Organization Guidelines for restricted irrigation. Our assessment of the full-scale household constructed wetland technology adds to the relatively low number of constructed wetland studies conducted outside a laboratory setting. Furthermore, it supports efforts to promote safe reuse of an underutilized resource at the rural household level in Sub-Saharan Africa and other arid regions in the developing world, supporting prospects for using treated greywater for agricultural reuse in regions that experience water scarcity, climate variability, and land degradation. Full article

Ninh Thuan is a coastal province in the central region of Vietnam and is characterized by a climate that is the hottest and driest in the country. Vietnam is also one of the top five countries most vulnerable to the effects of climate change worldwide. The objective of this study was a thorough evaluation of the quality of water supply sources and the impacts of water effluents from shrimp farms in Ninh Thuan province. The comprehensive evaluation was based on an understanding of the water–wastewater cycle employed in coastal shrimp cultivation. We combined qualitative and quantitative analyses in undertaking this study. Secondary data of groundwater and coastal water from the local periodic water quality monitoring program and national technical regulations were collected in the qualitative approach. We also integrated participatory rural appraisal techniques and field observations to understanding shrimp cultivation and the environmental and social impacts of shrimp farm effluents. The quantitative assessment consisted of measuring groundwater and wastewater contamination from shrimp ponds. As a result, four main reasons for water pollution issues were determined including extreme weather events, shrimp cultivation practices, degraded infrastructure, and mismanagement by local governance. Shrimp cultivation practices (feeding, using chemicals) have resulted in elevated levels of suspended solid (TSS, total Coliform), organic and carbon matter (BOD₅, COD), and excessive nutrients (total Nitrogen, NO₂-N, NO₃-N, PO₄-P). According to a local monitoring program, the coastal water and groundwater have experienced nutrient pollution. Groundwater sampling near the shrimp farms identified salinization elevated levels of Coliform from local domestic sewage sources. This study resulted in an integrated approach that evaluated the combined effects of extreme weather events and shrimp farming practices on the quality of coastal water. Also, the finding can be useful in recommending remedial water treatment technologies as a follow-on phase. Full article

Surface water resources have played a fundamental role in the development of human societies. Considering that different agricultural and industrial activities are carried out in the Acacias River basin, the main objective of this research was to analyze the influence of land use on the water quality in this area by identifying the main sources that influence river water quality. The methodology consisted of establishing 12 sampling stations with different land uses at three times. The National Sanitation Foundation-Water Quality Index (NSF-WQI) was applied to the obtained water quality evaluation data. The main results showed that the stations associated with urban centers presented a higher concentration in the following variables: fecal coliforms, biochemical oxygen demand (BOD) and phosphates. The principal components analysis revealed a close relation between the parameters of fecal coliforms, phosphates and BOD, and the pollution processes by organic matter, which are probably related to domestic and industrial wastewater discharges, and to detergents in urbanized areas. The parameters with the greatest range of values were total dissolved solids and turbidity. These results coincide with what was observed in the correlation analysis. Finally, nitrates showed higher concentrations at stations 6 and 7, associated with agricultural and industrial influence areas (i.e., oil palm crops in the basin). This study about the Acacias River is, thus, extremely important for the region, and concludes that the river’s self-purifying capacity allows improved water quality in the areas where the predominant land use is not associated with human settlements. Full article

Rural decentralized domestic wastewater treatment (DDWT) facilities, as an alternative to centralized sewage treatment plants, have been rapidly developed in rural areas worldwide. However, the lack of performance evaluations and operational status assessments of these facilities poses a significant obstacle to advancements in rural domestic wastewater treatment strategies. In the present study, 30 rural DDWT facilities with AO (anoxic/oxic) and AAO (anaerobic/anoxic/oxic) processes were investigated. The results revealed that only two facilities reached the first A-grade discharge standards of China, and twelve facilities met the first B-grade discharge standards for all ten wastewater quality indicators. Low standard-achieving ratios for biochemical oxygen demand (BOD₅) (63.3%), total nitrogen (TN) (60.0%), ammonia nitrogen (NH₃-N) (63.3%), total phosphorus (TP) (30.0%), suspended solids (SS) (46.7%), and fecal coliforms (FC) (26.7%) were calculated. Thus, it is essential to improve the treatment efficiency for BOD₅, TN, NH₃-N, TP, SS, and FC for rural wastewater treatment facilities. In addition, the AAO process had a median weighted average removal efficiency of 82.02%, which was better than that of the AO process (72.48%). Minor equipment failure rates, i.e., less than 20%, did not affect the operation of the rural DDWT facilities, since most equipment in the DDWT facilities was backed up. Notably, problems in several areas, e.g., process design, equipment selection, construction, and especially operations, influencing treatment performance should be investigated and proactively addressed. These findings provide specific suggestions for improvements that could benefit the long-term operation and management of rural DDWT facilities. Full article

Miang is a traditional fermented food made from Assam tea leaves and consumed as a snack. This study investigated the underground Miang fermentation process practiced by the Luar ethnic group in Laos, specifically examining the nutritional composition and microbial dynamics. Lactic acid bacteria and yeast were dominant in the fermentation process, reaching 8.43 and 8.50 log CFU/g after one week before gradually declining, while the coliform bacterial count was at 5.31 log CFU/g in the initial week but became undetectable in the later stages of fermentation. Next-generation sequencing identified Firmicutes (75.02%) and Proteobacteria (23.51%) as the primary phyla. Bacterial genera included Lactobacillus (73.36%) and Acetobacter (21.06%), with fungi mainly represented by Pichia (85.52%) and Candida (13.45%). Fundamental microbes such as Lactobacillus and Acetobacter were predominantly present, alongside Pichia and Candida, in the fungal communities. Microbial activities played a crucial role in generating essential enzymes for Miang’s transformation. The nutritional transformation appears to be complete at 5 weeks of fermentation. The moisture content in the final products was approximately 74% and correlated with a change in nitrogen-free extract (NFE) and crude fiber. The fat content showed a slight increase from 1.3% to 2.52%, but protein content slightly declined from 17.21% to 16.05%, whereas ash content did not change significantly. Key polysaccharide-degrading enzymes, particularly pectinase and β-mannanase, were revealed and peaked at 48.32 and 25.32 U/g Miang, respectively. The total polyphenols increased from 103.54 mg/g dry Miang to 144.19–155.52 mg/g during fermentation. The lowered IC₅₀ value indicated an increase in antioxidant activity. A fermentation period of at least 3 weeks proved to be optimal for enhancing antioxidant properties and bioactive compounds, and mitigating the risk of coliform bacteria. Full article

This study focused on exploring the effects of Neolamarckia cadamba leaf extract (NE) on the fermentation process and bacterial community of stylo (Stylosanthes guianensis) silage. Fresh raw materials of stylo were ensiled with 0%, 1%, and 2% NE, and various fermentation parameters, nitrogen components, and microbial compositions were analyzed at different time points (days 3, 7, 14, and 30) during the ensiling process. The experiment showed that, in comparison to the control group, incorporating NE into the ensiling process resulted in improved fermentation parameters, including increased lactic acid and acetic acid levels, as well as decreased pH, coliform population, and ammonia nitrogen concentration. Moreover, the relative abundances of Lactobacillus and Pediococcus were augmented, while the growth of Enterobacter was inhibited by the NE addition. These results suggest that NE has potential as a novel additive for silage, promoting a reduction in harmful bacteria and enhancements in the nutritional quality and fermentation characteristics of stylo silage. Full article