ABSTRACT
UV-LED irradiation has attracted attention in water and wastewater disinfection applications. However, no studies have quantitatively investigated the impact of light intensity on the UV dosage for the same magnitude of disinfection. This study presents a powerful 280 nm UV-LED photoreactor with adjustable light intensity to disinfect municipal wastewater contaminated with E. coli, SARS-CoV-2 genetic materials and others. The disinfection performance of the 280 nm LED was also compared with 405 nm visible light LEDs, in terms of inactivating E. coli and total coliforms, as well as reducing cATP activities. The results showed that the UV dose needed per log reduction of E. coli and total coliforms, as well as cATP, could be decreased by increasing the light intensity within the investigated range (0–9640 µW/cm2). Higher energy consumption is needed for microbial disinfection using the 405 nm LED when compared to 280 nm LED. The signal of SARS-CoV-2 genetic material in wastewater and the SARS-CoV-2 spike protein in pure water decreased upon 280 nm UV irradiation. © 2023 by the authors.
ABSTRACT
This research communication delineates the quality of pasteurized cow milk sold in Brazil from 2015 to 2020. A cross-sectional study was performed gathering 1749 samples, which were evaluated for microbiological and physicochemical parameters, including Salmonella spp., total and thermotolerant coliforms, freezing point, alkaline phosphatase and lactoperoxidase. The proportion of compliant and non-compliant samples was compared through the years and jurisdiction of the inspection services. Interactions between the design and response variables were assessed by log-linear analysis. Overall, a considerable non-conformity rate (12%) was found for at least one microbiological or physicochemical parameter. Post-pasteurization contamination by coliforms was the major challenge for dairy industries. Notably, the non-compliance rate for freezing point increased during the SARS-CoV-2 pandemic. In addition, the ability to comply was linked to the type of inspection service. Thus, it is suggested that the SARS-CoV-2 pandemic is affecting the dairy industries in Brazil, and we strengthen the need for more studies monitoring the quality of milk over the years, which could assist industries and regulatory agencies to ensure the compliance of pasteurized milk.
ABSTRACT
In developing countries, an estimated 80% of the population use traditional herbal medicines as part of their primary health care. As the market for herbal medicine expands in many African countries, partly due to their use in the treatment of COVID-19, there is the need to address all the associated safety issues. The aim of the study was to evaluate the microbial contamination of locally prepared, as well as imported foreign herbal products sold in Accra. Standard microbiological methods were employed in the enumeration of coliforms and the identification of pathogenic microbes in 60 herbal preparations that were sampled. A larger proportion (76.7%) of local herbal preparations was contaminated with bacteria as compared with imported ones (63.3%). Bacillus species and Pseudomonas aeruginosa were the predominant bacteria obtained from foreign and locally manufactured herbal preparations, respectively. A proportion of 36.7% (11) of the local samples were positive for coliform and the coliform counts ranged from 3.0 × 101 cfu/ml to 2.0 × 104 cfu/ml. Two foreign herbal samples (6.7%) were positive for coliforms; one had a count of 1.7 × 105 cfu/g while the other had 2 × 104 cfu/g. Herbal preparations sold in markets of Accra harbour several microbial pathogens; the risk is relatively higher for locally produced herbal preparations compared to imported herbal preparations. As a result, it is recommended that quality assurance in the production of local herbal preparations should be thoroughly monitored from the beginning of production to the final selling of the preparations. There is also the need to strengthen microbiological safety monitoring of imported herbal preparations.
ABSTRACT
Infectious diseases are those in which pathogens such as viruses and bacteria invade the human body and multiply, causing various adverse effects on the body. To prevent infectious diseases, it is important to sterilize and remove the causative microorganisms, as well as prevent the introduction and movement of microorganisms from the external environment. In our laboratory, we investigated the status of microbial contamination of shoes and floors shared within the university and confirmed that the degree of microbial contamination varied depending on the location. In this study, we investigated general live bacteria, fungi, Staphylococcus aureus, Escherichia coli, and coliform bacteria to determine the status of microbial contamination on the floors of two computer rooms. The number of colonies of general live bacteria and S. aureus tended to increase with the number of users, and vice versa;this trend was similar for fungi. No characteristic tendency was observed for £ coli and coliform bacteria.
ABSTRACT
While Rwanda is aiming at environmental pollution resilience and green growth, some industries are still discharging untreated effluent into the environment. This study gives a general overview of the compliance level of industrial effluent discharge in Rwanda and the linked negative environmental impacts. It comprises qualitative and quantitative analyses of data obtained from wastewater samples collected from five selected industries in Rwanda. The selected industries had previously been audited and monitored by the Rwanda Environment Management Authority (REMA), due to complains from neighboring residents. The study found that the effluent discharge from wastewater treatment plants (WWTP) for all concerned industries failed to comply with (i) oil and grease (O&G) national and international tolerable parameter limits or the (ii) fecal coliforms national standard. In addition, a compliance level of 66.7% was observed for key water quality monitoring parameters (pH, dissolved oxygen (DO), biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and heavy metals (i.e., lead (Pb), cadmium (Cd), and chromium (Cr)). Following these study findings, one industry was closed by the REMA for deliberately discharging untreated effluent into an adjacent river. This study recommends the adoption of the best available technology for effluent treatment, installation or renovation of existing WWTPs, and the relocation to industrial zones of industries adjacent to fragile environments.
ABSTRACT
Fecal contamination of water constitutes a serious health risk to humans and environmental ecosystems. This is mainly due to the fact that fecal material carries a variety of enteropathogens, which can enter and circulate in water bodies through fecal pollution. In this respect, the prompt identification of the polluting source(s) is pivotal to guiding appropriate target-specific remediation actions. Notably, microbial source tracking (MST) is widely applied to determine the host origin(s) contributing to fecal water pollution through the identification of zoogenic and/or anthropogenic sources of fecal environmental DNA (eDNA). A wide array of host-associated molecular markers have been developed and exploited for polluting source attribution in various aquatic ecosystems. This review is intended to provide the most up-to-date overview of genetic marker-based MST studies carried out in different water types, such as freshwaters (including surface and groundwaters) and seawaters (from coasts, beaches, lagoons, and estuaries), as well as drinking water systems. Focusing on the latest scientific progress/achievements, this work aims to gain updated knowledge on the applicability and robustness of using MST for water quality surveillance. Moreover, it also provides a future perspective on advancing MST applications for environmental research.
ABSTRACT
To improve business performance and achieve sustainable development through the concept of hot spring resource reuse, this study investigated the antibacterial effect of alginate-coated tea tree essential oil microcapsules and the effect of alginate microcapsules on the release of tea tree essential oil. The results revealed that 450 μm alginate/tea tree essential oil microcapsules (containing 720 ppm of tea tree essential oil) prepared using microfluidic assemblies effectively inhibited total bacteria, Escherichia coli, and Staphylococcus aureus in hot spring water. For alginate/tea tree essential oil microcapsules prepared under different conditions, at a fixed concentration of cross-linking reagents, the release time increased with the cross-linking time (10 min > 5 min > 1 min). At a fixed cross-linking time, the release time increased with the concentrations of cross-linking reagents (1 M > 0.5 M > 0.1 M). When the concentrations of cross-linking reagents and the cross-linking time were the same, the release time of cross-linking reagents increased with the strength of metal activity (Ca > Zn).
ABSTRACT
The efficient regioselective bromination and iodination of the nonsteroidal anti-inflammatory drug (NSAID) carprofen were achieved by using bromine and iodine monochloride in glacial acetic acid. The novel halogenated carprofen derivatives were functionalized at the carboxylic group by esterification. The regioselectivity of the halogenation reaction was evidenced by NMR spectroscopy and confirmed by X-ray analysis. The compounds were screened for their in vitro antibacterial activity against planktonic cells and also for their anti-biofilm effect, using Gram-positive bacteria (Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212) and Gram-negative bacteria (Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853). The cytotoxic activity of the novel compounds was tested against HeLa cells. The pharmacokinetic and pharmacodynamic profiles of carprofen derivatives, as well as their toxicity, were established by in silico analyses.
ABSTRACT
Onsite molecular diagnostics can revolutionize fecal pollution source tracking. We aimed to validate a method for onsite qPCR assays with a miniature speaker-sized Q qPCR instrument and other portable equipment items. We showed that marker genes for total bacteria (16S) and E. coli (rodA) in 100 mL of river water measured with this method agreed within ±0.3 log10 units with results obtained when using conventional laboratory equipment items. We then deployed the portable method in a mobile laboratory (‘lab in a van’) and quantified HF183 marker genes for human host associated Bacteroides in river water within 3 h of sampling. We also used the mobile laboratory to investigate urban river water and effluents from two storm drains and a retention pond and collected comprehensive microbial and physicochemical water quality data. We found significantly higher HF183 gene levels in the older storm drain compared to the river water (6.03 ± 0.04 vs. 4.23 ± 0.03 log10 gene copies per 100 mL), and a principal component analysis revealed that storm drain effluent retention in a pond beneficially altered water characteristics, making them more like those of the receiving river. In conclusion, onsite qPCR assays can be performed with portable equipment items to quickly test water.
ABSTRACT
Given recent worldwide environmental concerns, biodegradability, antibacterial activity, and healing properties around the wound area are vital features that should be taken into consideration while preparing biomedical materials such as wound dressings. Some of the available wound dressings present some major disadvantages. For example, low water vapor transmission rate (WVTR), inadequate exudates absorption, and the complex and high environmental cost of the disposal/recycling processes represent such drawbacks. In this paper, starch/polyvinyl alcohol (PVA) material with inserted nano-sized zinc-oxide particles (nZnO) (average size ≤ 100 nm) was made and altered using citric acid (CA). Both ensure an efficient antibacterial environment for wound-dressing materials. The film properties were assessed by UV–Vis spectrometry and were validated against the UV light transmission percentage of the starch/ polyvinyl alcohol (PVA)/ zinc-oxide nanoparticles (nZnO) composites. Analyses were conducted using X-ray Spectroscopy (EDX) and scanning electron microscopy (SEM) to investigate the structure and surface morphology of the materials. Moreover, to validate an ideal moisture content around the wound area, which is necessary for an optimum wound-healing process, the water vapor transmission rate of the film was measured. The new starch-based materials exhibited suitable physical and chemical properties, including solubility, gel fraction, fluid absorption, biodegradability, surface morphology (scanning electron microscopy imaging), and mechanical properties. Additionally, the pH level of the starch-based/nZnO film was measured to study the prospect of bacterial growth on this wound-dressing material. Furthermore, the in vitro antibacterial activity demonstrated that the dressings material effectively inhibited the growth and penetration of bacteria (Escherichia coli, Staphylococcus aureus).
ABSTRACT
In rapidly growing urban areas, such as Tijuana, Mexico, the presence of urban green spaces (UGSs) can help stem soil erosion, improve infiltration, slow runoff, decrease flooding, reduce air pollution, and mitigate climate change. In many water-scarce parts of the world, where centralized wastewater treatment is not accessible or practical, decentralized wastewater treatment systems (DEWATSs) have the potential to supply the water needed for irrigating UGSs. Here, we first review UGS systems supported by DEWATSs and the water quality guidelines and challenges associated with implementing DEWATSs for urban greening in different countries, including Mexico. We also critically examine the linkages between the lack of UGSs in Tijuana, Mexico, extensive soil erosion, and failing sanitation infrastructure that has led to the infamously poor water quality in the Tijuana River. Tijuana’s Ecoparque Wastewater Treatment Facility, a low-energy, aerobic DEWATS, which collects, treats, and discharges residential sewage for localized landscape irrigation, demonstrates how DEWATSs can meet the water demands for urban greening in rapidly urbanizing cities. The aerobic decentralized treatment using a gravity-fed trickling biofilter resulted in a >85% removal of chemical oxygen demand and dissolved organic carbon. Prior to treatment facility upgrades, there was a ~2 log reduction in total coliform and Escherichia coli and a <20% decrease in ammonia from the influent to final effluent. After the addition of a maturation pond in 2020, the effluent met Mexico standards for irrigation reuse, with a ~4 log reduction in fecal coliforms from the influent to final effluent. Case study results demonstrated the potential for decentralized wastewater treatment to meet effluent standards for landscape irrigation, provide water for urban greening, and prevent pollution in the Tijuana River and other urban waterways.
ABSTRACT
Currently, the world is facing a horrible situation due to SARS-CoV-2. Though its RNA was found in wastewater, there are still no studies on RNA contamination detected in sewage. Hence, a possible treatment of sewage is suggested in this work. The disinfection stage is extremely important in the treatment of effluents, minimizing the impacts on the receiving body of water and promoting public health. In this context, the sequential use of ultrasound and ultraviolet radiation, on a bench scale, was investigated as a way to improve the disinfection of anaerobically treated effluents. Two types of treated effluents were tested, by septic tank and anaerobic filter, for which, two ultrasound frequencies, 25 and 40 kHz, and four doses of UV, 3.6; 9.0; 18 and 36 mJ cm-2 were applied. Physicochemical and microbiological parameters were observed for individual and sequential assays. The better quality of the anaerobic filter effluent influenced the performance of both processes, decreasing the concentration of organic load and turbidity, even though a concentration of total coliforms and Escherichia coli occurred in the lowest quality effluent (septic tank). The application of ultrasound has a positive effect on the inactivation of total coliforms and E. coli up to 1.0 log and provides better conditions for ultraviolet radiation to be sequentially applied. The UV radiation applied for the septic tank and the anaerobic filter inactivates 2.5 log for total coliforms and 3.5 log for E. coli, respectively. It is suggested that the disinfection methods applied in this work to inactivate gram-negative bacteria (E. coli) can also be applied to secondary treatment effluents, as well as being better tested for viruses, protozoa, and helminths. Supplementary Information: The online version contains supplementary material available at 10.1007/s13762-021-03764-7.
ABSTRACT
BACKGROUND: Basic sanitation could be a potential indicator of the spread of coronavirus disease-2019 (COVID-19) and, in this context, space-time patterns are important tools with which to elucidate the spread of disease and identify risk factors. The aim of this study was to assess a possible association between basic sanitation indices and COVID-19 rates in all the 5570 municipalities of Brazil and its spatial distribution. METHODS: Data of COVID-19 cases registered in Brazil from 28 February until 31 May 2020 and independent variables associated with basic sanitation were included. RESULTS: High incidence rates were significantly associated with precarious water service index (0-25% coverage) and offstandard faecal coliforms index for tap water (5-50% and 75-100% of samples tested). A significant association between high mortality rates and sewage collection (0-25% coverage)/treatment (25-50% coverage) indices was also verified. In addition, clusters with significant spatial autocorrelation were identified mainly in the North and Northeast regions for mortality and incidence rates (high-high risk areas) and for offstandard faecal coliforms index. Those regions are considered the poorest in Brazil, presenting with low incomes, human agglomerations, as well as a poor basic sanitation system, which also hinder the implementation of COVID-19-preventative measures. CONCLUSIONS: A precarious basic sanitation infrastructure could potentially be associated with the high transmission of severe acute respiratory syndrome coronavirus-2 in Brazil.