Microbial Contamination Of Water Research Articles

Analyzing the presence of microbial contaminants in water sourced from shallow wells within Dodoma city, Tanzania

Analyzing the presence of microbial contaminants in water sourced from shallow wells within Dodoma city, Tanzania

Isolation and Identification of Bacterial Contamination Water Supply in Shendi City-Sudan

Background: Microbial contamination of water persists to be a significant problem; the usual source is human and animal fecal matter that has contaminated the water systems. The presence of bacteria and pathogenic organisms is of great concern when considering the safety of drinking water, as pathogenic organisms can cause watery diarrhea, cholera, typhoid fever, and other illnesses. Objective: This is a prospective tap water examination study to find groundwater microbiological fecal contamination. Materials and Methods: Water samples for laboratory examination were collected from a different area of Shendi city, which were classified as Tap water. Each sample was a collection in a sterile container and then isolated and Confirmation by biochemical test. Results: Tap water samples were found to be contaminated with E. coli about 80 (63.6%) samples, an indicator of contamination with the fecal matter of animals and humans. It was the isolation of other Gram-negative enteric bacteria such as Salmonella and pseudomonas these were not scientific indicators of water contamination by animal and human fecal matter. Conclusions: Tap Water was contaminated with feces and posed a health risk to consumers of that water and was found to be contaminated with E.coli bacteria. Future studies are needed to understand the complicated issues concerning water quality in the city. Community-led sanitation and hygiene education and better water source protection are urgently required.

Dental unit waterlines and health risks of pathogenic microbial contamination: An update review

Recently, there has been great concern about the levels of oral diseases associated with inappropriate and unsanitary oral care methods. In this line, the most serious is the water contamination with pathogenic microbes. Owing to the water microbial contamination of dental units, patients' oral health is threatened as a result of systemic disorders. Patients receiving treatment in dental unit waterlines were found to be affected by dangerous bacteria. Since both clients and dental staff are exposed to aerosols and water from dental equipment, the water should be of great quality. Due to the fact that dental unit waterlines (DUWLs) create a suitable environment for microbial development and the formation of biofilms, the water is often contaminated with a high density of several microorganisms (e.g., bacteria, fungi, protozoa, viruses), causing a health problem for dentists, patients and elderly patients, especially those with immunocompromised. This has fueled interest in presenting the current situation to shed light on (i) the microbial contamination of DUWLs and (ii) the connected infectious risks. It is essential that an elevated degree of mouth care be combined with adequate water quality and preventive dental units to maintain oral comfort, prevent deterioration, and promote public health. The growing population of individuals with compromised immune systems and the latest technological advancements concerning biofilms, water quality, etc. necessitate the implementation of improved management practices and the application of decontamination protocols for waterlines.

Comparison of the antimicrobial photocatalytic activities of SiO2 and Au@SiO2 nanostructures in water decontamination.

Photocatalytic disinfection of Escherichia coli suspension by silicon dioxide nanoparticles and silicon dioxide/gold nanocomposite in a batch reactor is investigated experimentally and results are compared. Silica nanoparticles were synthesized by Stöber method and pulsed laser ablation method was employed to prepare gold nanoparticles in distilled water. Composition of two nanoparticles species was carried out, using the second harmonic pulse of Nd:YAG laser, whose wavelength is in the absorption spectra of gold nanoparticles. Results confirm a decrease in the bandgap energy of silica nanoparticles after composition. Escherichia coli were selected as an indicator of the microbial water contamination. Disk diffusion method was used to evaluate the antimicrobial potential of SiO2 and Au@SiO2 nanostructures. Photocatalytic activities of both nanostructures were examined in dark, and under the irradiation of UV and visible light. In all conditions, the performance of Au@SiO2 nanocomposites was higher than SiO2 nanoparticles. In dark condition the higher biocidal nature and activity of Au nanoparticles and for the case of UV radiation, decreasing the bandgap energy and recombination rate of SiO2 nanoparticles after composition with Au increased the efficiency. For the case of visible light radiation, surface plasmon resonances effects, and local heat of Au nanoparticles were responsible for increasing the efficiency. RESEARCH HIGHLIGHTS: Doping large bandgap semiconductors nanostructures, such as silica with metal nanoparticles, such as gold will improve their photocatalytic activity to work in visible light. In this mechanism, gold nanoparticles act as effective traps to prevent the recombination of photogenerated electron-hole pairs. Other mechanisms, such as Schottky barrier formation, surface plasmon resonance absorption of gold nanoparticles, and biocidal nature of the gold nanoparticles are effective in increasing the efficiency of Au doped silica nanostructures.

Comparative evaluation of effect of sodium hypochlorite and chlorhexidine in dental unit waterline on aerosolized bacteria generated during dental treatment

BackgroundIn dentistry, nosocomial infection poses a great challenge to clinicians. The microbial contamination of water in dental unit waterlines (DUWLs) is ubiquitous. Such infected DUWLs can transmit oral microbes in the form of aerosols. Previous studies have suggested treating DUWLs with various disinfectants to reduce cross-contamination. The literature lacks a comparative evaluation of the effect of the use of 0.2% chlorhexidine (CHX) and 0.1% sodium hypochlorite (NaOCl) in DUWLs on aerosolized bacteria generated during dental procedures.ObjectiveTo compare the effect of NaOCl and CHX in DUWLs on aerosolized bacteria generated during restorative and endodontic procedures.Materials and methodsA total of 132 patients were equally divided into three groups (n = 44 in each group) according to the content of DUWL as follows.Group I—0.1% NaOClGroup II—0.2% CHXGroup III—distilled water (Positive control)One-way ANOVA was performed and the Kruskal–Wallis test was used for intergroup comparison.ResultsFor the restorative procedure, inter-group comparison of mean colony-forming units (CFU) scores showed a statistically significant difference between the groups (p- .001) with the score of group 3 higher than group 2 followed by group 1. For the endodontics, an inter-group comparison of CFU scores showed a statistically significant difference between the groups (p- .003) with the mean score in group 1 being the lowest and group 3 being the highest.ConclusionThe addition of NaOCl or CHX in DUWLs shows an effective reduction in aerosolized bacteria compared to distilled water.

Synthesis of Fe3O4/ZrO2/ZnO nanoparticle for enhancing visible light photocatalytic and antibacterial activity

BackgroundNitroaromatic (especially nitrophenols) compounds, dyes, drugs, pesticides, and photographic chemicals are widely used in industries. Para-nitrophenol (4-NP) is one of the nitroaromatic compounds that was found in wastewater from pharmaceutical and other industrial sources. Also, the presence of microbial contamination in water leads to irreversible damage to human health. Thus, the treatment of bacteria and the effective elimination of 4-NP are both significant issues to human health. MethodsThe preparation of easily recyclable photocatalytic compounds with high-performance activity for degradation of the hazardous aromatic compounds and antimicrobial activity (Gram-negative and Gram-positive bacteria) are highly desirable for different practical applications. In this study, a novel magnetic photocatalyst, Fe3O4/ZrO2/ZnO nanoparticle (NP), was synthesized via an inexpensive protocol at mild conditions. Significant findingsThe surface morphology and chemical composition of Fe3O4/ZrO2/ZnO NP were studied by FE-SEM, TEM, EDS, VSM, XRD, UV-DRS, PL, XPS and ICP. Fe3O4/ZrO2/ZnO NP exhibited high activity in photocatalytic degrading para-nitrophenol (4-NP) of about 90 % after 38 min under solar light irradiation. The antibacterial activity of Fe3O4/ZrO2/ZnO NP against E. coli, and S. aureus was evaluated by calculation of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). MIC and MBC values for E. coli were determined to be 0.125 and 1.25 (µg/mL), respectively. Also, these amounts for S. aureus were evaluated and equal to 1.25 and 12.5 (µg/mL), respectively. The reusability of the nanoparticle was shown by the high performance of the photocatalyst in the degradation of 4-NP after five runs (>80 %). Also, the Fe3O4/ZrO2/ZnO NP demonstrated high antibacterial activity in the low dosage of the nanoparticle. Therefore, the ZrO2/ZnO NP supported by Fe3O4 perform well in antibacterial activity and degradation of 4-NP.

Water quality monitoring in southern Brazil and the assessment of risk factors related to contamination by coliforms and Escherichia coli.

The potability of water, including underground sources, is constantly affected by human activities. To assess water quality and water security in rural and urban areas of southern Brazil, a quantitative, retrospective analysis of water samples collected monthly by the Brazilian health authorities (19,687 samples from 2013 to 2021) was performed. In rural areas, 5,979 water samples (77.54%) were found to be contaminated by coliform bacteria and 3,431 (44.50%) by Escherichia coli. In addition, 1,616 (20.95%) of the contaminated samples were significantly correlated with rainfall amount. In urban areas, 1,268 (10.95%) of the samples contained coliform bacteria and 293 (2.53%) of these samples contained E. coli, with the factor of rainfall associated with 1,081 samples (9.33%) with bacterial contamination. In terms of physicochemical parameters, turbidity exceeded the national standard (5 uT) in 448 (2.32%) samples and fluoride fell below the required level (0.8 mg/L) in 106 samples (0.54%). The presence of free residual chlorine (0.2-2.0 mg/L) was verified in 846 samples (14.38%) in rural areas and in 10,825 samples (56.13%) in urban areas. These results suggest a strong association between rainfall factors and physicochemical alterations, as well as the risk of greater microbial contamination of water for human consumption.

High-strength hydrophilic N-halamines chitosan and cellulose nanofibers membranes with repeated bactericidal properties

Direct addition of disinfectants and membrane separation techniques have been common methods to address microbial contamination in water. However, disinfectants may generate toxic by-products, and even minor damage or biofilm formation on filtration membranes can lead to a heightened risk of microbial contamination. Consequently, how to quickly and safely disinfect microbial contaminated water sources remains a huge challenge. In this study, the high-strength broad-spectrum antibacterial CNF/CS composite membrane was fabricated by utilizing cellulose nanofibers (CNF) to reinforce the structure of chitosan (CS). The resulting CNF/CS composite membrane exhibits an impressive tensile strength of 148 MPa and boasts an active chlorine content of 5.29 %. Notably, even after undergoing 50 washing cycles and 10 repeated chlorination procedures, the structural integrity and high active chlorine content of the composite membrane remain preserved, validating its exceptional strength, stability, and chlorine rechargeability. Additionally, the CNF/CS antibacterial materials demonstrate remarkable attributes in terms of rapid sterilization, sustained and consistent release of active chlorine, and efficient inhibition of biofilm formation, demonstrating great potential in efficient, green, and safe sterilization.

Risk of Faecal Contamination of Water Used by Food Vendors in Owerri Munipality, Imo State Nigeria

Assessment of faecal contamination of water is a key factor in assessing the quality and safety of food. It also reveals the level of hygiene adopted by food handlers in the course of preparation and serving of such foods. This study assessed the risk of microbial contamination of water used by food vendors in Owerri munipality, Imo State Nigeria between January-December 2019 with an emphasis on total coliforms and the faecal coliforms/ faecal indicator bacteria (FIB) – Escherichia coli (E. coli) and thermotolerant coliforms (TTC). One hundred and thirty water samples collected across three vending types (street vendors, high level and low level restaurants) were evaluated for microbial contamination using standard methods. Data obtained was statistically analyzed with p-value set at 0.05 significance level. The result identified Enterobacter spp. and Klebsiella spp. The result showed that 48.46% (63) of the 130 water samples examined were contaminated with coliform bacteria, of which 20 (22.22%) samples had faecal coliform bacteria, representing 10.77% of the entire water samples examined. Of the 64 samples from water used for food preparation, 12.50% (8) had faecal coliform bacteria as against 9.09% (6) of 66 samples collected from water offered to customers for drinking. The result showed that 116 (89.23%) of the 130 water samples recorded no faecal coliform contamination, hence they were considered excellent based on the guidelines for determination of faecal contamination of water. Two samples had faecal coliform counts of 1-3 per 100 ml of water accounting for 1.54% of water samples, which is considered Satisfactory. The result revealed suspicious (4-9 per 100 ml) coliform count in 9 (6.92%) water samples, while three water samples (2.31%) had ≥10 count and are classified as unsatisfactory. The result revealed that 89.23% (116) of the examined water samples were of ‘no risk’ to the public, which was significantly higher than 8.46% (11) and 2.31% (3) recognized as being of low and intermediate risk respectively (p <0.05). High and very high risk water samples were not encountered in the study. This trend in qualification of risk of water samples reflected in the two types of water usages, and the observed differences was however not statistically significant (p>0.05).

Examination of water quality at the household level and its association with diarrhea among young children in Ghana: Results from UNICEF-MICS6 survey

Ghana has made significant progress in expanding water services, but microbial contamination of water is still a major public health problem. The objectives of the study were to: 1) Examine sociodemographic and water access related predictors for the point of use or drinking water quality among rural and urban households, and; 2) Determine the association between the point of use water quality and prevalence of diarrhea among young children in rural and urban households. A secondary data analysis was carried out using the Ghana UNICEF-MICS6 survey taking into account the complex survey design. Logistic regression models were used to carry out the objectives. Among the 2317 households included for water quality testing, majority reported using improved source of drinking water. However, use of unimproved source of water was more common among rural households. In examining water quality at the point of use, it was found that more than 60% of the samples had mid to high levels of E. coli count, with significantly more common among rural compared to urban households (p < .0001). The prevalence of diarrhea among under 5 children was 16.9%. In estimating the risk, E. coli count was not associated with higher diarrhea prevalence. However in urban areas, water storage was associated with increased risk of caregiver-reported diarrhea in children. Also, other factors such as child’s age, maternal education, region and household wealth index predicted diarrhea prevalence. In Ghana, contaminated point of use drinking water is more common in rural household, and in urban areas, water storage is associated with increased risk of caregiver-reported diarrhea in children. In the future, investigation of living condition and environmental hygiene is warranted to further understand different pathways through which risk of diarrhea increases among children.

A review on the versatility of Carica papaya seed: an agrogenic waste for the removal of organic, inorganic and microbial contaminants in water

AbstractThe advent of civilization, coupled with growing industrialization in many countries, is placing more demand on the available water sources. At the same time, the daily surge in wastes generated by man's anthropogenic activities has led to microbial, organic and inorganic contamination of water sources. Based on available evidence, significant research efforts are being made into the use of low‐cost agricultural materials such as Carica papaya seed (CPS) in the removal of these contaminants from water sources in a bid to provide clean water. In the present review, the organic, inorganic and microbial contaminants in waters were elucidated. Furthermore, the chemical composition of the CPS was illustrated. The adsorption capacity and efficiency of CPS and their composites in the remediation of the selected contaminants were discussed while identifying the various factors affecting the adsorption efficiency. Finally, the reusability of this agricultural material was discussed. Solution pH was identified as a major factor influencing the sorption process. The high removal efficiency reported in the studies that adopted CPS showed its vast potential in the elimination of contaminants from water sources. Also, the regenerative potential of the adsorbent over several cycles indicated its long‐term use. The economic feasibility and environmental sustainability afforded by using CPS chart a path for further investigation into the use of other low‐cost agricultural materials in the elimination of environmental contaminants. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

Homogenous Sono-Fenton reaction can trigger long term bactericidal effect against Acinetobacter baumannii due to residual stress induced by reactive oxygen species

Gastrointestinal diseases caused by microbial contamination of water has been one of the enduring public health challenges of the mankind, wherefore demands continual innovation in the contemporary water treatment techniques. Here, a systematic study was carried out to elucidate the bactericidal mechanism of ultrasound assisted Fenton reaction (Sono-Fenton: SF) against multidrug resistant Acinetobacter baumannii. Inactivation of ≈5 × 106 CFU/mL of A. baumannii was achieved within 90 min of SF under weak acidic conditions using 20 mg L-1 of H2O2 and 2 mg L-1 of Fe2+. Having more than 99 % inactivation efficiency, no reactivation of the bacteria was observed for 96 h. After SF, a combination of ultrasound and H2O2 was found to be more efficient although complete inactivation was not achieved within the same time frame. Experimental evidence suggests the generation of multiple reactive oxygen species (ROS) such as H2O2, •OH and O2•–. The synergistic effect of ROS and ultrasound may have resulted in the membrane damage of the bacteria as evident from the electron microscopy analysis. Interestingly, our data also suggests that the residual stress associated with SF could have long term bactericidal effect and is influenced by incubation temperature. Comparative transcriptomic analysis showed that NirD/YgiW/YdeI family stress tolerance protein, KGG domain containing proteins, and PspC domain containing proteins, all known to control the stress induced responses in bacteria was significantly upregulated after SF treatment. Additionally, genes regulating transcription (GntR) and translation (rpsQ) have been downregulated which may induce a nutrient and metabolite limiting conditions in the bacterial cell. The bacterial inactivation ability of SF process was further validated with real water samples collected from natural systems and therefore, advocate the possible real-world applications.

Assessment of Microbial Contamination in the Infulene River Basin, Mozambique

Water microbial contamination is one of the major threats to human health. The study focus is on Infulene River Basin, a urban catchment with mainly informal settlements, with limited water supply and sanitation. In the catchment there are two wastewater treatment plants, one hospital and beer factory located on the banks of the main stream; water from this stream is used for urban agriculture and domestic uses by some dwellers. These factors present a significant health risk from water-borne diseases. At the moment there is limited knowledge about the level of microbial contamination of the different sources of water at the disposal of the communities. Thus, a preliminary study on fecal microbial contamination was conducted targeting the Infulene River and the drainage system from the nearby Maputo city draining into the system, with additional investigation on the drinking water provided by the city water supply company. The quantification of Total Coliforms (TC) and Escherichia coli (EC) was conducted at several sampling locations. Results were compared with official drinking water standards. Eighty two percent (82%) and 61% of Infulene river water and drainage water samples were positive for TC (105 to 109 NPN/100 mL) and EC (105 to 107 NPN/100 mL), respectively. For drinking water samples, 63% and 23% were positive for TC (up to 6000 NPN/100 mL) and EC (up to 1000 NPN/100 mL), respectively. Higher microbial contamination was found in neighborhoods with the poorest sanitation and shallow groundwater, i.e., Chamanculo, Xipamanine, Mafalala, Aeroporto and Maxaquene, a situation that was more expressive during the rainy season. Overall, the study confirmed the high vulnerability to microbial contamination of all sources investigated due to poor sanitation and lack of drainage infrastructure. The risks to human health might be even higher considering that contaminated water is used for gardening of vegetable watering and domestic use.

Advanced nanostructured materials in solar interfacial steam generation and desalination against pathogens: combatting microbial-contaminants in water – a critical review

Application of solar steam generation and solar stills against pathogens (bacteria, viruses, protozoa, fungi, antimicrobial resistance) via different mechanisms such as ROS, temperature, UV, surface engineering and contact by nanomaterial highlighted.

Drinking water quality monitoring of centralized water storage reservoirs in various zones of the National University

Physico-chemical and microbiological pollutants may compromise quality of drinking water. This study aims to highlight various physico-chemical and microbial parameters of drinking water samples from centralized water storage reservoirs of National University. Major water quality parameters which were examined in this study includes pH, Electrical conductivity (EC), Turbidity, Total suspended solids (TSS), Total dissolved solids (TDS), Dissolved oxygen (DO), Residual chlorine, Hardness, Alkalinity. Moreover, microbial analysis of water samples was also carried out through Most Probable Number technique (MPN). Results show that all the physico-chemical parameters were within prescribed limits of World Health Organization and Pakistan Drinking Water Quality Standards (WHO/PDWQS) in both underground and overhead water storage reservoirs except DO ( 9.05-9.2 and 9.05-9.1 mg/L ), TSS (10-20 and 3.3-10 mg/L) and residual chlorine (0.08-0.14 and 0.19-0.28 mg/L) respectively. The MPN index values for both underground and overhead water storage reservoirs ranges between 16- >23 and 1.1-12 respectively and it shows high microbial contamination in water due to low detection of residual chlorine. The results highlight that water from centralized water storage reservoirs of National University is unfit for drinking purposes. Statistical analysis such as paired t-test also reveals that water quality parameters from underground and overhead storage reservoirs are not significantly different from each other except EC and TDS having P values <0.05. It is necessary to safeguard water contamination in water storage reservoirs by monitoring regular inspections and chemical cleaning of water storage reservoirs otherwise it will cause serious threats to well-being of the community.
 Key words: water storage reservoirs, drinking water, microbial quality of water, physico-chemical parameters, paired t-test

The study of microbial contamination of water and sanitary facilities in the Karaganda regional clinical hospital during different seasons

In modern conditions, the quality of water supply and the state of water management facilities play a key role in maintaining the health of people and animals, as well as the life quality of the population. In this regard, we set the goal of our research to assess the level of microbial contamination of water and sanitary facilities in the Regional Clinical Hospital of Karaganda district as the central and most powerful medical institution in the region in different seasons of the year. Based on the results of our study, the following conclusions can be drawn: during the research period, seasonal variability of indicators in the studied samples of tap water can be traced. The water of the central water supply is characterized by systematic excesses of both total coliform and thermotolerant coliform bacteria. In the city of Karaganda, there is a great stability in the quality of water supply, regardless of the seasons, despite the excess of standard indicators. It can talk about either the low quality of water treatment, or about quality problems in the water supply network at the sampling points (Regional Clinical Hospital of Karaganda). At the same time, it is worth noting the high percentage (almost 98 %) of positive samples in the spring. In winter, there is a lower percentage of positive samples and a significantly lower microbial quantity. The quality of drinking water decreases in the spring, we believe that the most likely reason for the deterioration in the quality of drinking water is the ingress of melt water and rainwater into the source. Violations of the technological conditions for the operation of water treatment facilities, secondary water pollution in worn-out water distribution networks could also be the cause of unsatisfactory results. In the Regional Clinical Hospital of Karaganda, a higher percentage of positive swabs is noted, which is associated with a higher load on the regional hospital, as well as a better supply of antimicrobial disinfectants, which leads to selective selection of more resistant strains.

Three staged integrated community-based water filter system for potable water by effective removal of contaminants from ground water

Potable water scarcity is a dire problem faced worldwide due to contaminated ground water. Microbial contaminants, heavy metals chromium (Cr) and metalloid such as arsenic (As) are some of the major pollutants of ground water and pose serious health hazards. The present work is focused to design a multifunctional three compartment integrated water filtration system for community use and its validation at both lab and pilot scale. The top compartment is mainly for removal of flocculating contamination with improvement of taste and odor of drinking water. The second compartment consists of functionalized sand layers for removal of metal and microbial contaminants and the third compartment comprises of nanoparticle embedded ceramic candles to further eliminate any remaining contaminants. The developed integrated water filter containing various types of materials were characterized through flow rate, scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) before and after filtration. Moreover, the analysis of various physiological parameters such as pH, turbidity, total dissolved solids and hardness pre and post filtration elucidated stable and improved results. Micro-computed tomography (micro-CT) analysis of baked ceramic candle showed substantial increased porosity of ~83.11 ± 2.17 % in comparison to unbaked candle (26.09 ± 1.33 %). The inductively coupled plasma mass spectrometry (ICP-MS) analysis demonstrated significant reduction of As and Cr levels before and after filtration, which was further confirmed by EDS mapping. Microbial testing showed hierarchal decrease in microbial load after each stage at lab scale. This low-cost, multistage, gravity-based filtration system proved effective in removal of heavy metal and microbial contaminants in water and provides the potable filtrate for daily use. Thus, the integrated system with simple design without requiring major infrastructure and promising results may lead to its potential real-time application for supplying potable water to large populations, particularly in rural populations who cannot afford sophisticated water purification system.

Determination of microbial contamination of water used in the household for domestic purposes in Mombasa County, Kenya

Background: Globally, 45% of the global population, showing that the compliance level is very low in most developing countries. In Kenya, 10% of all deaths caused by waterborne illnesses are due to water scarcity and poor sanitation. Mombasa County is facing a major problem in the provision of domestic water to its residents, thus causing a water shortage.Methods: Descriptive cross-sectional study was conducted in Mombasa County between November 2020-March 2021. 55 water samples were randomly collected for analysis of microbial contamination. Using stata for analysis, t-test was calculated to determine the relationship with p<0.05.Results: TC mean for boreholes was ±761.68 CFU and tap water was ±712.23 CFU. There was a significant difference in means between the two groups for TC (t=7.38, df=41.94, p=0.000). Faecal coliforms (FC) for borehole and tap water was ±739.52 CFU and ±115.42 CFU respectively. FC showed a significant difference between the two groups (t=3.74, df=36.84 and p=0.0003). HPC means for borehole and tap water of water were ±7730.62 CFU and ±4092.12 CFU respectively. There was no significant difference in means for HPC for the two groups (t=1.73, df=53 and p=0.0445). 34.3% (n=12) and 20% (n=4) of boreholes and tap water were contaminated with salmonella respectively. None of the water samples collected had Shigella. Conclusions: All borehole water samples stored in the household storage containers were more contaminated than tap water, hence not fit to be consumed in the household.

The qualitative characteristics of the water of Lake Habbaniyah

The presence of lakes has some advantages and disadvantages, which are reflected on the quality and quality of water, and then restrict it to some different uses. Lake Habbaniyah worked on changing the properties of the water in it and raising the values ​​of most of the elements, and it affected the water quality of the Euphrates River, as the value of the salts increased from (431) mg / liter at the entrance to the lake, to reach (597) mg / liter when it exited the lake at the canal The flies regulator, as all sites indicated bacterial contamination of the lake water, the number of colon bacteria ranged between (930-300) cells/mm. Most of the water ions fall within the permissible limits for drinking purposes (human-animal), as for biological pollutants (colon and fecal bacteria), their presence is conclusive evidence of microbial contamination of water, which restricts the use of lake water for drinking purposes. For agricultural purposes, and for building and construction purposes, as for industrial purposes, there is a limited restriction for some industries that require water of certain specifications that are not available in lake water. As for the presence of coliform and fecal bacteria, it restricted the use of lake water for some uses, especially for drinking purposes.

UV/Chlorine Process: An Efficient Advanced Oxidation Process with Multiple Radicals and Functions in Water Treatment.

Because of the deterioration of global water quality, the occurrence of chemical and microbial contaminants in water raises serious concerns for the health of the population. Identifying and developing effective and environmentally friendly water treatment technologies are critical to obtain clean water. Among the various technologies for the purification of water, ultraviolet photolysis of chlorine (UV/chlorine), an emerging advanced oxidation process (AOP), has multiple functions for the control of contaminants via the production of hydroxyl radicals (HO·) and reactive chlorine species (RCS), such as Cl·, ClO·, and Cl2·-.This Account centers around the radical chemistry of RCS and HO· in different water matrices and their roles and mechanisms in the abatement of contaminants. The concentrations of Cl·, ClO·, and Cl2·- are comparable to or higher than those of HO· (10-14 to 10-13 M). The reactivities of RCS are more selective than HO· with a broader range of second-order rate constants (k). The k values of Cl· toward most aromatics are higher or similar as compared to those of HO·, while those of Cl2·- and ClO· are less reactive but more selective toward aromatics containing electron-donating functional groups. Their major reaction mechanisms with Cl· are electron transfer and addition, while those with ClO· and Cl2·- primarily involve electron transfer. As for aliphatics, their reactivities with both HO· and RCS are much lower than those of aromatics. The reaction mechanisms for most of them with Cl· and Cl2·- are hydrogen abstraction, except for olefins, which are addition. In addition, RCS greatly contribute to the inactivation of microbial contaminants.Toward future application, the UV/chlorine process has both pros and cons. Compared with the traditional HO·-based AOP of UV/H2O2, UV/chlorine is more efficient and energy-saving for oxidation and disinfection, and its efficiency is less affected by water matrix components. However, the formation of toxic byproducts in UV/chlorine limits its application scenarios. In dissolved organic matter (DOM)-rich water, the formation of halogenated byproducts is enhanced in UV/chlorine. In the presence of ammonia, reactive nitrogen species (RNS) (e.g., ·NO and ·NO2) are involved, and highly toxic nitro(so) products such as nitro(so)-phenolics and N-nitrosodimethylamine are generated. For a niche application, the UV/chlorine process is recommended to be utilized in water with low levels of DOM and ammonia.Strategies should be developed to make full use of highly reactive species (RCS and HO·) for the abatement of target contaminants and to reduce the formation of toxic byproducts. For example, the UV/chlorine process can be used in tandem with other treatments to create multiple barriers for the production of safe water. In addition, halogen radicals are very important in ecosystems as well as other areas such as medical therapy and organic synthesis. UV/chlorine is the most efficient homogeneous system to generate halogen radicals, and thus it provides a perfect system to investigate the fates of halogen radicals for interdisciplinary research.