Current Issue : January-March Volume : 2025 Issue Number : 1 Articles : 5 Articles
The emergence of antibiotic resistance (AR) poses a signicant threat to both public health and aquatic ecosystems. Wastewater treatment plants (WWTPs) have been identied as potential hotspots for disseminating AR in the environment. However, only a limited number of studies have been conducted on AR dissemination through WWTPs in Sri Lanka. To address this knowledge gap in AR dissemination through WWTP operations in Sri Lanka, we critically examined the global situation of WWTPs as hotspots for transmiing antibiotic-resistant bacteria (ARB) and antibiotic-resistant genes (ARGs) by evaluating more than a hundred peer-reviewed international publications and available national publications. Our ndings discuss the current state of operating WWTPs in the country and highlight the research needed in controlling AR dissemination. The results revealed that the impact of dierent wastewater types, such as clinical, veterinary, domestic, and industrial, on the dissemination of AR has not been extensively studied in Sri Lanka; furthermore, the eectiveness of various wastewater treatment techniques in removing ARGs requires further investigation to improve the technologies. Furthermore, existing studies have not explored deeply enough the potential public health and ecological risks posed by AR dissemination through WWTPs....
Effective disinfection processes have been investigated to provide pathogen-free drinking water. Due to growing concern about the potential negative effects of cyanobacteria in portable water, their treatment has gained more attention recently. This study aims to compare the inhibition efficiencies of Gram-negative bacteria (Escherichia coli; E. coli), Gram-positive bacteria (Bacillus subtilis; B. subtilis), and cyanobacteria (Microcystis aeruginosa; M. aeruginosa) using UV-C and solar irradiation, and their combination process with H2O2. Over 6 log removal value (LRV) of E. coli and B. subtilis was achieved within 1 min of UV-C irradiation (0.76 ± 0.02 mW/cm2). The solar and solar/H2O2 (50 mg/L) processes effectively reduced (>99%) both bacteria after 20 min. E. coli was more sensitive to hydroxyl radicals (•OH) compared to the B. subtilis due to a different cell wall structure, resulting in a 0.18–0.62 higher LRV than B. subtilis. However, solar-based processes did not effectively inhibit M. aeruginosa (>52.23%). The UV-C/H2O2 (50 mg/L) process showed the highest inhibition rate for M. aeruginosa (77.83%) due to the generation of •OH, leading to oxidative damage to cells. Additionally, chlorophyll-a (Chl-a) was measured to indicate cell lysis of M. aeruginosa. The removal rate of Chla extracted by viable M. aeruginosa was higher using the UV-C process (93.03%) rather than the UV-C/H2O2 process (80.95%), because UV-C irradiation could be most effective in damaging Chl-a....
Fluoride, whose levels are higher than the World Health Organization (WHO) recommended level of 1.5 mg/l, results in health issues. Therefore, fluoride contamination is a matter that calls for concern by all people and governments, especially in countries where volcanicity has been experienced. This study sought to model spatial variation, distribution, and prediction of fluoride levels in groundwater in the river Njoro catchment. This study aimed to observe the levels of fluoride and give recommendations for identifying and delineating potential sites for safe groundwater for use by the local population and advice on the water treatment and de-fluoridation methods. In this study, borehole water samples were collected for laboratory analysis of fluoride levels. The study adopted descriptive and correlation statistical analysis. The sources of data included: field surveys where data on fluoride levels were collected, remotely sensed data, GIS, and geostatistically interpolated data. The results through geostatistical interpolation observed varied distribution and variations of fluoride levels in the River Njoro catchment....
Phenolic compounds (PhCs) are aromatic compounds with benzene rings that have one or more hydroxyl groups. They are found or formed in the atmosphere due to various factors such as combustion processes, industrial emissions, oxidation of volatile organic compounds (VOCs), and other photochemical reactions. Due to properties such as relatively high Henry’s law constants and moderate/high water solubility, PhCs are vulnerable to reactions in atmospheric liquid phase conditions with high relative humidity, fog or cloudy conditions. PhCs can lead to the formation of secondary organic aerosols (SOAs), which can have negative eects on atmospheric conditions and human health. Changes in the optical properties of PhCs impact solar radiation absorption and scattering, potentially inuencing climate. Additionally, PhCs may interact with other atmospheric constituents, potentially aecting cloud or fog formation and properties, which in turn can impact climate and precipitation paerns. Therefore, monitoring and controlling the emission of PhCs is essential. This paper discusses the transformation processes of PhCs in the atmosphere, including direct conversion of phenol, nitrate-induced and nitrite-induced reactions, hydroxylation reactions and oxidation processes involving triplet excited state organics, also providing a detailed analysis of the transformation processes. The ndings lay a theoretical foundation for the future monitoring and control of atmospheric pollutants....
Biological monitoring using environmental DNA (eDNA) technology has expanded from micro- to macro-organisms. In aquatic eDNA studies, large volumes of water need to be filtered rapidly in the field, which requires development of effective eDNA collection devices. In this study, we introduce a novel portable eDNA collection system containing a GM dual-channel water filter and a DNA extraction kit adapted to large filter membranes (ø 100 mm). The water filter is powered by a high-capacity lithium battery (9,000 mA), which operates two peristaltic pumps and maintains a continuous filtration rate of up to 1 L/min for 5 h in outdoor settings. For sample collection, the optimum conditions are still water and turbidity below 8 nephelometric turbidity units. This allows for the filtration of 10 L of water within 10 min by use of a 0.22-μm filter. Metagenomic and 12S metabarcoding sequencing showed that the DNA extraction quality and species annotation accuracy of our custom DNA extraction kit, which was tailored for this system, rivaled the performance of established kits. The GM water filter’s enrichment mode gave consistent results with vacuum filtration, which greatly reduced the filtration time for large water samples, while accurately reproducing species annotations. This innovation streamlines the eDNA collection and annotation process and offers substantial benefits for biodiversity monitoring and conservation efforts....
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