Abstract This study aims to investigate the water quality characteristics of Qaroun Lake and their impact on microbial diversity. Advanced analyses were conducted to assess the physicochemical and microbiological indicators during two seasons, winter (January 2022) and summer (July 2023), revealing insights into the Lake’s environmental conditions. Our results indicated that the water quality of the Lake was notably influenced by agricultural and municipal drainage from the surrounding communities. High values of pH, total dissolved solids (TDS), electrical conductivity (EC), biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total alkalinity and a noticeable depletion in dissolved oxygen (DO) were observed. Furthermore, pollution from total and fecal coliforms and fecal streptococci exceeded the permissible limits, particularly during the winter season, implicating agricultural and sewage waste as significant contributors to this environmental challenge. The study also identified ten bacterial and fungal strains in the Lake through a bioinformatics approach, each exhibiting different 16S rRNA/18S rRNA gene sizes. All sequence data were submitted to the NCBI GenBank database (USA). The antibiotic resistance profiles of 246 bacterial isolates from 12 sites along the Lake were determined using 20 antibiotics. All bacterial isolates exhibited 100% resistance to Ampicillin, Carbenicillin, Methicillin, Vancomycin, Erythromycin, and Clindamycin. Multiple antibiotic resistance (MAR) was observed in bacterial isolates from all sites, possibly linked to sewage discharge and other anthropogenic sources in the Lake. The calculated water quality index (WQI) categorized Qaroun Lake water as “bad” aligning with the analytical data. The correlation coefficient matrix demonstrated several significant relationships between water quality pairs, highlighting a strong positive correlation (r = + 0.82) between physicochemical and bacteriological indicators in polluted Lake water. This study strongly recommends enforcing Egyptian laws to protect Qaroun Lake water from pollution, emphasizing the need to address the identified environmental challenges and preserve the region’s ecological balance.

Abstract This study experimentally examined the performance of pooled stilling basins with positive and negative steps, with and without baffle blocks, for mitigating local scour and enhancing energy dissipation downstream of sluice gates. The study combined 1, 2, and 3 negative steps with 1, 2, 3, and 4 positive steps. Additionally, the experimental setup included the investigation of adding 1, 2, or 3 rows of baffle blocks, with each row configuration being tested at three different vertical height specifications. Experiments were conducted in a 15.6 m long, 0.30 m wide, and 0.468 m deep recirculating flume at Froude numbers 1.0 to 2.0 under a fixed submergence ratio ( $${s}_{r}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>s</mml:mi> <mml:mi>r</mml:mi> </mml:msub> </mml:math> = 3.3). A 2.0 m long and 0.1 m deep mobile sand bed was installed downstream of the basin. A total of 12 models with 81 test runs, were examined in the laboratory under various flow conditions. Results showed that steeped basin, model $${C}_{1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>C</mml:mi> <mml:mn>1</mml:mn> </mml:msub> </mml:math> (two negative steps followed by four positive steps), reduced scour by up to 48%. Adding baffle blocks; with the tallest blocks ( $${E}_{2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>E</mml:mi> <mml:mn>2</mml:mn> </mml:msub> </mml:math> , $$\frac{{h}_{b}}{K}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mfrac> <mml:msub> <mml:mi>h</mml:mi> <mml:mi>b</mml:mi> </mml:msub> <mml:mi>K</mml:mi> </mml:mfrac> </mml:math> =1.5) and blockage ratio of 5%, further increased the reduction to 54%. Energy dissipation improved by up to 59% for model $${B}_{4}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msub> <mml:mi>B</mml:mi> <mml:mn>4</mml:mn> </mml:msub> </mml:math> (one negative step followed by four positive steps). Adding single row configurations of baffles with blockage area 5% and relative height ( $$\frac{{h}_{b}}{K}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mfrac> <mml:msub> <mml:mi>h</mml:mi> <mml:mi>b</mml:mi> </mml:msub> <mml:mi>K</mml:mi> </mml:mfrac> </mml:math> =1) provided the most efficient balance between scour reduction and energy loss. Finally, experimental data are used to derive empirical formulas through multiple linear regression analysis.

Assessment of the ecological-health risk and heavy metal pollution in drinking water was carried out in the Enyigba-Ameka Pb–Zn mining region in order to establish present level of heavy metal enrichments. Thirty-five water samples were collected from various source of drinking water in two seasons (dry and wet) and analyzed according to the American Public Health Association (APHA) standard. Data was interpreted using nine indexical models. Water quality index (WQI) values obtained showed that 9%, 20%, and 71% of the samples indicated “moderately polluted water, polluted water, and excessively polluted water” respectively during dry season and 14%, 37%, and 49%, representing “moderately polluted water, polluted water, and excessively polluted water” respectively during wet season. Synthetic pollution index (SPI) values for dry season were 9%, 17%, 48%, and 26% indicating slightly polluted water, moderately polluted water, highly polluted water, and unfit respectively for drinking purposes while for wet season, 6%, 28%, 43%, and 23% representing slightly polluted water, moderately polluted water, highly polluted water, and unfit respectively for drinking purposes. Hazard quotient (HQ) revealed that cadmium (Cd) was the major heavy metal influencing undesirable health conditions in both the adult and children populations in both seasons. Contamination index (CI) classified 35 water samples as low contamination in dry season and 28 in wet season while heavy metal evaluation index (HEI) classified 35 samples as low contamination in both seasons. The study’s findings provide insights into contamination by heavy metals for the protection of human health and water supply in the Enyigba-Ameka Pb–Zn mining region.

ABSTRACT Freshwater scarcity is an escalating global issue, requiring innovative approaches to ensure water quality and sustainability. This study aimed to isolate actinomycetes from soil and wastewater environments that have effectiveness in removing bacteria associated with wastewater. A total of 25 actinomycetes isolates were obtained from the collected soil and wastewater samples for further analysis. These isolates will be evaluated for their potential to act as biocontrol agents against wastewater-associated bacteria, highlighting their role in enhancing wastewater treatment processes. Actinomycetes isolates were screened for antibacterial activity using the cross-streak method, and the most effective isolate (KW8) was further analyzed. Antibacterial compounds were extracted using ethyl acetate and characterized via gas chromatography-mass spectrometry (GC-MS), library data identified 13 bioactive compounds: 2-methyl-7-nonadecene, 10-heneicosene, n-hexadecanoic acid, cetene, 1-docosene, trans-geranylgeraniol, [1,1”-biphenyl]-4,4”-diol, 3,3“,5,5”-tetrakis(1,1-dimethylethyl), pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(phenylmethyl), 1-nonadecene, trichloroacetic acid, hexadecyl ester, 1-eicosanol, squalene, and dodecane, 1,2-dibromo. KW8 exhibited broad-spectrum antibacterial activity, with the highest inhibition observed against Enterococcus faecalis (20 ± 1.3 mm) and the lowest against Pseudomonas aeruginosa (12 ± 0.9 mm). The strain was identified through 16S rRNA sequencing and confirmed as Streptomyces gramineus. These findings highlight KW8’s potential as an effective antimicrobial agent for wastewater treatment, providing a sustainable solution to address microbial contamination and promoting environmental health.

ABSTRACT A high proportion of chemical substances and microorganisms in water can result in water-borne diseases which can be harmful to humans when such water is consumed untreated. We used physico-chemical and microbial characteristics to assessed the water quality of selected water sources in Benue South, Nigeria. Three Local Government Areas namely, Otukpo, Ohimini, and Apa were studied. This study combined field and laboratory-based approach where water samples were collected from particular water sources within the study area from January 2023, March–May 2023 (four months). Temperature, pH, TDS, and EC were measured insitu while TSS, COD, DO, BOD, and turbidity were determined in the laboratory following standard procedures, and microbial analysis was estimated based on standard microbiological procedures. Data obtained were analyzed using descriptive statistics (mean± S.D), two-way ANOVA, and Post Hoc test and Principal Component Analysis (PCA) was used to check the association between physico-chemical variables of the sites sampled in the study area. The results of the physico-chemical variables showed markedly high values of EC, BOD, COD, TDS, TSS, and turbidity with no significant difference (p > 0.05) in physico-chemical values across themonths. Water temperature, DO, EC, and TDS were positively associated with S5 in the first component of the PCA while COD and pH were slightly negatively associated with S2 in the first component of the PCA. Microorganisms detected were Klebsiella sp., Proteus sp., Shigella sp., Bacillus sp., Escherichia coli and Staphyloccus sp. The highest coliform count was recorded in S1: January: >1,600 MPN/100 mL: March (>1400MPN/100 mL), April 2023: (>1300MPN/100 mL) and May: (>950MPN/100 mL). Total viable count (TVC; 136 ± 39.10) and (TCC); 90.75 ± 27.80) were highest in S5 across the months. The post hoc test showed that TCC and TVC were not significantly different among sites (p > 0.05). Elevated total coliform counts were recorded in the sites above the recommended limit by the World Health Organization standard (3 coliform/100 mL). Therefore, there is the need for regulatory action to address water quality issues within the study area.

ABSTRACT Recently, the decline in water quality in the Upper Awash River Basin, Ethiopia, has been exacerbated by increasing industrialization, urbanization and agricultural activities. The aim of this study was to identify the major pollutants and their sources. To achieve the main objectives, the physicochemical qualities of 197 groundwater, 60 surface water (collected from ten different rivers), and 60 drinking water samples were analyzed using standard procedures. Also, sanitary data associated with the different drinking water supply systems were collected. Principal component analysis (PCA) and positive matrix factorization (PMF) modeling were used for data analysis. The present results showed that the most dominant hydrochemical water types were Na-HCO3 (65.0%) and Ca-HCO3 (32.5%) for groundwater, while Na-CO3 (35.0%), Na-HCO3 (13.3%) and Ca-CO3 (11.7%) were observed within the surface water. The results from sanitary assessment indicated that the drinking water supply systems were exposed to contamination with 66.7% from animal grazing, 61.7% from agricultural farming, and 40.0% from domestic waste. About 64% of surface water pollutants came from natural geological sources, with 29% from agriculture and 7% from other human activities. For groundwater, the contaminants were 63% from geological structure, 17% from agriculture, and 20% from other anthropogenic sources. Since agricultural and other anthropogenic activities contributed significantly toward water pollution in the study area, it needs to be addressed through appropriate domestic waste disposal and fertilizer management systems such as applying fertilizers in precise amounts to reduce runoff and leaching as well as establish vegetated buffer zones near water bodies to absorb excess nutrients.

ABSTRACT The economy of Vietnam is significantly influenced by agriculture, forestry, and fisheries; thus, developing analytical methods to assess water quality is crucial. Salinization is an escalating concern in the Mekong Delta, particularly in Ben Tre province, where it adversely affects the livelihoods and local economy. In saline water, besides NaCl, which is the predominant component, other ions such as K+, Ca2+, Mg2+, and SO4 2− are vital for crop development. This study introduces an ion chromatography technique with conductivity detection capable of simultaneously analyzing six ions in saline water samples with high precision. The standard curves demonstrated excellent linearity with a correlation coefficient (R2 >0.995) and commendable repeatability (%RSD <5%) for concentration ranges of 1–10 mg L−1 for cations, 0–10 mg L−1 for SO4 2−, and 10–50 mg L−1 for Cl−. The outcomes will be compared with those of reference methods, including Flame Atomic Absorption Spectrometry, Mohr Titration, and Turbidimetric Methods, revealing no significant differences in ion concentration determinations across six saline water backgrounds in Ben Tre province.

ABSTRACT Bahr Yousef is a meandering earthen canal and is considered one of the most morphologically active semi-natural streams in the west of River Nile region in Egypt. This stream is usually exposed to periodic changes in cross-sections due to scour, deposition, and improper periodic dredging activities. The objectives of the present study are to assess the morphological behavior and hydraulic performance of Bahr Yousef canal and to identify the flooding areas. Combination of field data, satellite images, and numerical modeling methods is used and achieved to simulate the dynamic behavior of the second reach of Bahr Yousef canal from Dahab regulator (km 77.700) to Saqoula regulator (km 179.450) under different flow scenarios. The designed, actual, and target flows were modeled using HEC-RAS modeling program to evaluate the canal’s hydraulic efficiency. The results showed that in the case of a passing target discharge, the flooded areas increased by 25.8%, and the most significant inundated areas are located between 135 km and 160 km along the studied reach. The canal narrowed by 5.8% from an average of 71.35 m in 2004 to 67.22 m in 2023 due to human activities and natural meandering phenomena. Significant sedimentation (10,671,870 m3) and erosion (4,593,143.67 m3) observed along the studied reach, restricting its capacity to handle target discharge. Recommendations are given to control the scour and sedimentation processes in certain critical curves along Bahr Yousef canal. This is very important to avoid inundation problems that have devastating consequences, including foundation collapses, crop damage, and property loss.