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The prevalence of fecal indicator bacteria in relation to physical parameters were observed twice a year in selected points of the Indus River. Eight representative sampling locations were selected, and samples were collected twice a year, i.e., in the dry and wet seasons, for a total of 16 samples. The fecal coliform (FC) to fecal streptococci (FS) ratio was used to identify the source of fecal contamination. Results showed severe fecal contamination levels exceeding the allowable limits of WHO and Pak-EPA. Except for pH and TDS, the physical parameters were also not found within allowable limits at various sampling locations. The comparison of dry and wet seasons reveals higher microbial loads in the wet season. The FC/FS ratio linked polluted waters to human sources (37.5%), animal sources (25%), mixed pollution with the dominance of human pollution (25%), and mixed pollution with the dominance of domestic pollution (12.5%) in dry and human sources (25%), animal sources (25%), mixed pollution with the dominance of human pollution (37.5%) and mixed pollution with the dominance of domestic pollution (12.5%) in wet season. Pearson’s correlation test showed a strong positive correlation (r = 0.71 to 0.99) between TDS and salinity in both dry and wet seasons, and a moderately strong correlation (r = 0.41 to 0.70) between various microbial and physical parameters. It is strongly advised that careless municipal wastewater disposal into rivers be prohibited. To prevent contaminated water from mixing with river water, an appropriate sewage and drainage system should be implemented.

In this study, the performance of four different pre-treatment alternatives for granular media filtration, namely, settling, aeration, coarse media filtration and chemical coagulation were compared experimentally. Further, analytical hierarchy process (AHP) was used to compare their performance based on economic, environmental, technical and performance criteria. Performance of settling and aeration were evaluated up to 24 h duration. The coarse media filter was intermittently operated with 10 L of greywater in downflow mode while alum was used for chemical coagulation. Experimental results showed that settling up to 6 h did not show significant removal of different pollutants whereas 24 h settling resulted in moderate removal of turbidity and organic content but was not efficient in the removal of nutrients and faecal coliforms. Chemical coagulation reduced 93, 66, 48 and 97% of turbidity, COD, NH4-N and faecal coliforms, respectively from greywater but resulted in excessive sludge generation and is difficult to adopt on-site and requires skilled supervision. Coarse filtration of greywater resulted in 61, 41, 36 and 35% removal of turbidity, COD, PO4-P and faecal coliforms, respectively. Considering different criteria AHP gave coarse filtration as the best pre-treatment option to the granular media filters treating greywater.

An innovative nature-based technology for wastewater treatment is the hybrid biofiltration, which combines complex symbiotic relationships between plants, earthworms and microorganisms with adequate support components. This latter could be optimized using organic supports. The aim of this research was to evaluate the performance of hybrid biofilters based on rice husks/sawdust treating grey wastewater from mining camps. Four biofilters using an active layer (rice husks/sawdust: 50/50%, v/v) at 60(B60) and 45(B45) cm height and operating for 64 days at a hydraulic loading rate between 1 and 5 m3/m2d were monitored. Eisenia foetida Savigny and Cyperus papyrus L. were used as a biotic component. COD, N-NH4+, NO3−, NO2−, PO43− and fecal coliforms were weekly monitored. Results showed that the most efficient HB was using 60 cm as an active layer and operating at 3 m3/m2d, which reported average removal efficiencies for COD, NH4+, NO3−, PO43− and fecal coliforms up to 85, 89, 47, 49 and 99.9%, respectively. Organic support improved the rate growth for Cyperus papirus L. and E. foetida Savigny up to 50%. Hybrid biofiltration using organic residues is low-cost, providing all-encompassing operational and performance features, improving the wastewater reclamation opportunities.

The Litany River has encountered severe environmental pollution. This study focused on assessing the pollution level in the upper basin of the Litany River by monitoring seasonal variation of water quality and testing physicochemical parameters and microbial qualities. A total of 72 freshwater samples were taken from six sites for 1 year during the four seasons. The microbiological parameters included total coliform, fecal coliform, and Escherichia coli counts. The physicochemical parameters comprised pH, total dissolved solids, nitrate, sodium, potassium, biochemical oxygen demand, chemical oxygen demand, total nitrogen, and total phosphorus. The microbiological quality of samples was evaluated by comparing the fecal pollution indicators loads to the SEQ-EAUX2003 standard for irrigation, and the physicochemical analyses were assessed according to Lebanese Standards Institution (LIBNOR) NL161: 2016 and the World Health Organization (WHO) Guidelines for Water Quality. The results revealed that most physicochemical parameters are not within the permitted limit of LIBNOR and WHO, especially in sites S2, S3, and S6 during the dry seasons. The pH ranged between 6 and 8.16. The total dissolved solids reached 1948 mg/L. The nitrate, sodium, and potassium ranged between 0 and 253 mg/L. The total nitrogen and total phosphorous reached 103 and 5.16 mg/L, respectively. The chemical oxygen demand reached 2210 mg/L, and the biochemical oxygen demand reached 732 mg/L. Concerning the microbiological analysis, fecal pollution was detected in all sites during all seasons, with detectable higher values during the dry seasons, and all samples were considered to be non-conforming, with significant spatiotemporal variation of most parameters. Our results highlight the need to take measures to prevent the high level of pollution. This could be achieved by monthly water quality monitoring of the upper basin and introducing appropriate guidelines to detect pathogens and toxic chemicals that affect the entire ecosystem and lead to severe public health issues.

Surface waters are essential for meeting the needs of the world. In many regions, stream water quality is a major concern due to contamination from multiple sources. Stream water is also susceptible to climatic events and land-use practices influencing its catchment. Understanding the impact of such events on stream water quality is crucial for managing and protecting aquatic ecosystems and providing safe drinking water to communities that rely on these streams. Hence, monitoring and evaluating stream water quality holds significance in identifying potential hazards and implementing suitable management strategies. In this paper, a novel effort was made to determine the relative feature importance of a set of watershed characteristics (precipitation, temperature, urban land use, agricultural land use, and forest land-use factors) on four important water quality parameters (WQPs): fecal coliforms (FC), turbidity, pH, and conductivity of the Upper Green River watershed, Kentucky, USA. Random forest (RF), an ensemble learning method, was used to predict the WQPs from the causal parameters and determine the feature importance characteristics of the four WQPs previously mentioned. This model demonstrated that precipitation and temperature are the most influential factors on FC, turbidity, and pH. Forest land use and temperature are the two most important factors for conductivity. The novel feature importance factors of the RF model have likewise been confirmed for each WQP. In modeling stream WQPs, the developed the RF model outperformed the artificial neural network (ANN) model. Using the RF model, we obtain regression coefficients of (0.93, 0.74, and 0.94) for pH in training, testing, and overall. We obtain regression coefficients of (0.60, 0.64, and 0.61) using the ANN model. ⁠⁠⁠⁠⁠⁠⁠Overall, the RF model was more effective than the ANN model in modeling stream WQPs. The model identified precipitation and temperature as the most influential factors on FC, turbidity, and pH, while forest land use and temperature were the most important factors in determining conductivity. It is also found that land use factors are important to improve the accuracy of WQPs predictions from climate variables. The results of this study can be used by authorities to better understand and control pollution at the watershed scale.

Background Ensuring the availability of safe drinking water remains a critical challenge in developing countries, including Ethiopia. Therefore, this paper aimed to investigate the prevalence of fecal coliform and E. coli bacteria and, geographical, children availability, and seasonal exposure assessment through a meta-analysis. Methods Two independent review groups extensively searched internet databases for English-language research articles published between 2013 and 2023. This systematic review and meta-analysis followed PRISMA guidelines. The methodological quality of each included study was evaluated using the STROBE guidelines. Publication bias was assessed by visual inspection of a funnel plot and then tested by the Egger regression test, and meta-analysis was performed using DerSimonian and Laird random-effects models with inverse variance weighting. Subgroup analyses were also conducted to explore heterogeneity. Results Out of 48 potentially relevant studies, only 21 fulfilled the inclusion criteria and were considered for meta-analysis. The pooled prevalence of fecal coliform and E. coli was 64% (95% CI: 56.0–71.0%, I 2  = 95.8%) and 54% (95% CI: 45.7–62.3%, I 2  = 94.2%), respectively. Subgroup analysis revealed that the prevalence of fecal coliform bacteria increased during the wet season (70%) compared to the dry season (60%), particularly in households with under-five children (74%) compared to all households (61%), in rural (68%) versus urban (66%) areas, and in regions with high prevalence such as Amhara (71%), Gambela (71%), and Oromia (70%). Similarly, the prevalence of E. coli was higher in households with under-five children (66%) than in all households (46%). Conclusions The analysis highlights the higher prevalence of fecal coliform and E. coli within households drinking water, indicating that these bacteria are a significant public health concern. Moreover, these findings emphasize the critical need for targeted interventions aimed at improving drinking water quality to reduce the risk of fecal contamination and enhance public health outcomes for susceptible groups, including households with under-five children, in particular geographical areas such as the Amhara, Gambela, and Oromia regions, as well as rural areas, at point-of-use, and during the rainy season. Registration This review was registered on PROSPERO (registration ID - CRD42023448812).

Solar disinfection (SODIS) involves exposing water stored in transparent polyethylene terephthalate (PET) containers to the sun for about 6 h of strong sunlight, after which the water is rendered safe for consumption. This study investigated the seasonal effect of reactor characteristics on the inactivation kinetics/constant of faecal coliforms by conducting a [2.sup.3] factorial experiment, involving two levels of PET bottle size, PET bottle thickness, and PET bottle rear surface, uniquely combined to form 8 SODIS reactors/experimental units. The faecal coliform population of hourly samples taken from the 8 SODIS reactors showed that the inactivation kinetics/constant depends on the irradiation energy and maximum water temperature as dictated by the reactor characteristics. The average rate constant of the reflective reactors (1.37 [+ or -] 0.43 [h.sup.-1]) was significantly better (p < 0.001) than the absorptive reactors (1.17 [+ or -] 0.59 [h.sup.-1]) between June and October. The average rate constant of the small PET bottles (1.73 [+ or -] 0.65 [h.sup.-1]) is significantly higher (p < 0.002) than the large PET bottles (1.46 [+ or -] 0.51 [h.sup.-1]) from December to May; while the average rate constant of the light PET bottles (1.58 [+ or -] 0.64 [h.sup.-1]) is significantly better (p < 0.001) than the thick PET bottles (1.41 [+ or -] 0.52 [h.sup.-1]) year-round. Analyses of results confirmed a two-way interaction effect between PET bottle size and PET bottle thickness and between PET bottle rear surface and PET bottle thickness for periods with average radiation intensity of 450-500 W x [m.sup.-2]. Although container size and thickness were the most significant factors, combining light PET bottles with absorptive rear-surface could extend the applicability of SODIS to regions that fall short of the recommended radiation intensity threshold of 500 W x [m.sup.-2] for 5 h.

Deep sequencing technologies can be used to evaluate pathogens in environmental samples. The objective of this study was to use this technology to evaluate Sargassum samples that were characterized by different stranding times, one classified as short‐term stranded (STS) and another classified as long‐term stranded (LTS) Sargassum . Nine replicates of the STS Sargassum showed a range in Shannon diversity between 3.04 and 3.38, whereas 11 replicates of LTS showed a range between 1.17 and 1.22. Nonmetric multidimensional scaling analysis showed distinct differences between STS and LTS by about 0.5 coordinate units, while variations within replicates ranged by 0.1 coordinate units. Comparison between the two Sargassum samples showed a greater abundance of Vibrio species in STS Sargassum when compared to LTS Sargassum , with major pathogenic forms observed for Vibrio alginolyticus (11%), Vibrio parahaemolyticus (1.5%), and Vibrio vulnificus (0.29%). Additional known human pathogens were observed, including Listeria monocytogenes , Legionella pneumophila , and Staphylococcus aureus , as well as the presence of gut commensals and fecal coliforms. Overall results show that deep sequencing analysis of these environmental samples was reproducible. Given the abundance of pathogenic bacteria, more research is needed to evaluate the risk of disease transmission as Sargassum strands and decomposes on coastal beaches.

Antibiotics are known to enter the environment, not only by human excretion but also through livestock/aquaculture, healthcare facilities, and pharmaceutical industry waste. Once in the environment, antibiotics have the ability to provide a selective pressure in microbial communities thus selecting for resistance. Bayou Lafourche of Southeastern Louisiana serves as the raw source of drinking water for 300,000 people in the region and has previously been shown to receive high amounts of fecal contamination. Four sites along the bayou and one site from its input source on the Mississippi River were monitored for water chemistry, total and fecal coliform estimates, and presence of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARG) for a period of 1 year. Four waste-associated bacterial isolates were tested for resistance to antibiotics (tetracycline, sulfamethoxazole/trimethoprim, cefoxitin, meropenem, imipenem, erythromycin, and vancomycin). Resistant bacteria were further examined with PCR/electrophoresis to confirm the presence of antibiotic resistance genes (Sul1, tet(A), tet(W), tet(X), IMP, KPC, and OXA-48). The bayou appears to meet the Louisiana Department of Environmental Quality (LDEQ) criteria for water chemistry, yet fecal coliforms were consistently higher than LDEQ thresholds, thus indicating fecal contamination. Enterobacteriaceae isolates showed 13.6%, 10.9%, and 19.8% resistant to tetracycline, sulfamethoxazole/trimethoprim, and cefoxitin, respectively, and 11 isolates were confirmed for presence of either tet(A) or Sul1 resistance genes. High fecal coliforms and presence of ARB/ARG may both indicate a presence of anthropogenic or agricultural source of fecal contamination.

The Edwards Aquifer is the primary water resource for over 2 million people in Texas and faces challenges including fecal contamination of water recharging the aquifer, while effectiveness of best management practices (BMPs) such as detention basins in mitigating fecal pollution remains poorly understood. For this study, the inlet and outlet of a detention basin overlying the aquifer’s recharge zone were sampled following storm events using automated samplers. Microbial source tracking and culture-based methods were used to determine the occurrence and removal of fecal genetic markers and fecal coliform bacteria in collected water samples. Markers included E. coli (EC23S857), Enterococcus (Entero1), human (HF183), canine (BacCan), and bird (GFD). Fecal coliforms, EC23S857, and Entero1 were detected following each storm event. GFD was the most frequent host-associated marker detected (91% of samples), followed by BacCan (46%), and HF183 (17%). Wilcoxon signed rank tests indicated significantly lower outlet concentrations for fecal coliforms, EC23S857, and Entero1, but not for HF183, GFD, and BacCan. Higher GFD and BacCan outlet concentrations may be due to factors independent of basin design, such as the non-point source nature of bird fecal contamination and domestic dog care practices in neighborhoods contributing to the basin. Mann–Whitney tests showed marker concentrations were not significantly higher during instances of fecal coliform water quality criterion exceedance, except for E. coli , and that fecal coliform concentrations were not significantly different based on marker detection. Overall, results suggest that the detention basin is effective in attenuating fecal contamination associated with fecal coliforms and the general markers, but not for host-associated markers. Consequently, management efforts should focus on mitigating dog and bird-associated fecal pollution in the study region.