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Microcystin-LR (MC-LR), the most common algal toxin in freshwater, poses an escalating threat to safe drinking water. This study aims to develop an engineered biofiltration system for water treatment, employing a composite of poly(diallyldimethylammonium chloride)-biochar (PDDA-BC) as a filtration medium. The objective is to capture MC-LR selectively and quickly from water, enabling subsequent biodegradation of toxin by bacteria embedded on the composite. The results showed that PDDA-BC exhibited a high selectivity in adsorbing MC-LR, even in the presence of competing natural organic matter and anions. The adsorption kinetics of MC-LR was faster, and capacity was greater compared to traditional adsorbents, achieving a capture rate of 98% for MC-LR (200 μg/L) within minutes to tens of minutes. Notably, the efficient adsorption of MC-LR was also observed in natural lake waters, underscoring the substantial potential of PDDA-BC for immobilizing MC-LR during biofiltration. Density functional theory calculations revealed that the synergetic effects of electrostatic interaction and π-π stacking predominantly contribute to the adsorption selectivity of MC-LR. Furthermore, experimental results validated that the combination of PDDA-BC with MC-degrading bacteria offered a promising and effective approach to achieve a sustainable removal of MC-LR through an "adsorption-biodegradation" process.

Bacteria are key organisms in energy and nutrient cycles, and predicting the effects of temperature change on bacterial activity is important in assessing global change effects. A changing in situ temperature will affect the temperature adaptation of bacterial growth in lake water, both long term in response to global change, and short term in response to seasonal variations. The rate of adaptation may, however, depend on whether temperature is increasing or decreasing, since bacterial growth and turnover scale with temperature. Temperature adaptation was studied for winter (in situ temperature 2.5 °C) and summer communities (16.5 °C) from a temperate lake in Southern Sweden by exposing them to a temperature treatment gradient between 0 and 30 °C in ~ 5 °C increments. This resulted mainly in a temperature increase for the winter and a decrease for the summer community. Temperature adaptation of bacterial community growth was estimated as leucine incorporation using a temperature Sensitivity Index (SI, log growth at 35 °C/4 °C), where higher values indicate adaptation to higher temperatures. High treatment temperatures resulted in higher SI within days for the winter community, resulting in an expected level of community adaptation within 2 weeks. Adaptation for the summer community was also correlated to treatment temperature, but the rate of adaption was slower. Even after 5 weeks, the bacterial community had not fully adapted to the lowest temperature conditions. Thus, during periods of increasing temperature, the bacterial community will rapidly adapt to function optimally, while decreasing temperature may result in long periods of non-optimal functioning. [ABSTRACT FROM AUTHOR]

Abstract Contaminated lake water and fish can be sources of bacterial pathogens of public health concern, including pathogenic E. coli. Within Ethiopia, specifically, Central Oromia, raw fish consumption is a common practice. Although there are few reports on occurrence of E. coli O157 in fish destined for human consumption and children under five years, information on the transmission pathways of E. coli O157 and other sorbitol non-fermenting (SN-F) E. coli from water-to-fish-to-human, and their virulence factors and antimicrobial resistant determinants along the fish supply chain is lacking. The study aimed to investigate the occurrence, molecular characteristics, and antimicrobial susceptibility of E. coli O157 and other SN-F E. coli strains in fish, lake water and humans in central Oromia, Ethiopia. A total of 750 samples (450 fish samples, 150 water samples, 150 human stool samples) were collected from five lakes and three health facilities. The samples were processed following the standard protocol recommended by European Food Safety Authority and Kirby–Bauer disc diffusion method for detection of the bacteria, and antimicrobial susceptibility tests, respectively. Molecular characterization of presumptive isolates was performed using Whole-Genome Sequencing (WGS) for serotyping, determination of virulence factors, antimicrobial resistance traits, and genetic linkage of the isolates. Overall, 3.9% (29/750) of the samples had SN-F E. coli; of which 6.7% (n = 10), 1.8% (n = 8) and 7.3% (n = 11) were retrieved from water, fish, and diarrheic human patients, respectively. The WGS confirmed that all the isolates were SN-F non-O157: H7 E. coli strains. We reported two new E. coli strains with unknown O-antigen from fish and human samples. All the strains have multiple virulence factors and one or more genes encoding for them. Genetic relatedness was observed among strains from the same sources (water, fish, and humans). Most isolates were resistant to ampicillin (100%), tetracycline (100%), cefotaxime (100%), ceftazidime (100%), meropenem (100%), nalidixic acid (93.1%) and sulfamethoxazole/trimethoprim (79.3%). Majority of the strains were resistant to chloramphenicol (58.6%) and ciprofloxacin (48.3%), while small fraction showed resistance to azithromycin (3.45%). Isolates had an overall MDR profile of 87.5%. Majority, (62.1%; n = 18) of the strains had acquired MDR traits. Genes encoding for mutational resistance and Extended-spectrum beta-lactamases (ESBL) were also detected. In conclusion, our study revealed the occurrence of virulent and MDR SN-F E. coli strains in water, fish, and humans. Although no genetic relatedness was observed among strains from various sources, the genomic clustering among strains from the same sources strongly suggests the potential risk of transmission along the supply chain at the human–fish-environment interface if strict hygienic fish production is not in place. Further robust genetic study of the new strains with unknown O-antigens, and the epidemiology of SN-F E. coli is required to elucidate the molecular profile and public health implications of the pathogens.

The main purpose of this study is to assess the urban lake water quality along the coastal region of Miri City, Sarawak, East Malaysia. This study concentrates on the hydrochemical characteristics and the mechanisms controlling the suitability of the lakes for domestic, irrigation, and industrial purposes. A total of 15 lake water samples were collected and analysed for physical parameters, major ions, nutrients, BOD, COD, and heavy metals. The results show that Lakes 6, 7, and 8 commonly exceeded the National Drinking Water Quality Standards (NDWQS) limits, particularly in physical parameters and major ions. The cation dominance was Na+ > Mg2+ > K+ > Ca2+, while the anion dominance was Cl− > HCO3− > SO42−. It is inferred that lake 8 was affected by the seawater intrusion through the inlet flow, resulting in an excess concentration of ions present in that lake. The concentrations of heavy metals in these lakes were considerably low, indicating that most of them were from the geogenic source. Most of the lakes were NaCl water type and the main controlling mechanism were weathering and ionic exchange processes, with anthropogenic impacts. Based on the calculated Water Quality Index (WQI) according to the National Water Quality Standards (NWQS), all lakes were suitable for irrigation use (class IV), while most of these lakes fell under the "polluted" index. Apart from that, based on the National Lake Water Quality Standards (NLWQS), all lakes were classified under category D, indicating that the lakes must be kept in good condition. According to the irrigation quality indices, lakes 1, 2, 3, 4, and 5 were the most suitable for irrigation purposes. As for metal pollution indices (HPI and HEI), lakes 1, 2, 3, 4, 5, and 15 were considered safe with low pollution status. From the multivariate statistical analysis, it is deduced that both anthropogenic and geogenic impacts mostly influenced the quality of these lake waters. The outcome of this study will help the policymakers under the national water department in sustainable management of water resources in this region. [ABSTRACT FROM AUTHOR]

This study utilizes a natural air diffusion cathode (ADC) and an ultraviolet lamp to construct a UV/H2O2 reactor for the in situ synthesis and activation of H2O2 and evaluates its potential application in practical lake water treatment. The results indicate that the reactor exhibits stable treatment performance during a continuous flow experiment of 80 h. The air diffusion cathode maintains an H2O2 concentration of above 350 mg·L−1 in sodium sulfate electrolyte and shows no decreasing trend. Under the condition of approximately 59% H2O2 utilization, the removal rates of COD and TOC are 37.6% and 40.0%, respectively; the rate of reduction of A254 is 64.3%; while the total bacterial count removal rate reaches 100%. Large organic molecules in surface water are degraded to small organic molecules and mineralized to inorganic minor molecules. It effectively ameliorates the problem of organic pollution of surface water and effectively kills bacteria and improves the microbiological safety of the water body. Therefore, the UV/H2O2 system developed in this study, based on electrochemically produced H2O2, is an effective method for treating micro-polluted surface water. [ABSTRACT FROM AUTHOR]

Polystyrene has been extensively used in various industries and consumer products, leading to high quantities of waste. In areas with improper waste management, plastic products reach water systems. Various substances can migrate from plastics into water and become part of a fraction, generically named fluorescent dissolved organic matter. The aim of this study is to determine the level of fluorescent organic matter that leaches from polystyrene into lake water samples, which have a relatively high natural organic matter content. Thus, coffee cup lids have been added to triplicate water samples and compared to a control sample, over a period of 3 weeks. Results show that fluorescent substances migrate from plastic into lake water samples. Styrene oligomers, toluene, and phenol derivates have been proposed as substances that potentially leach from polystyrene products. These compounds may have an impact on fluorescence properties of dissolved organic matter, by potentially inhibiting the microbial activity in water or by forming complex compounds. [ABSTRACT FROM AUTHOR]

Measurements of oxygen and hydrogen stable isotope ratios (δ18O and δD) in meteoric waters provide insight to overlapping effects of evaporation, precipitation, and mixing on basin scale hydrology. This study of waters collected between 2016 and 2021 in the Turkana Basin, northern Kenya, uses δ18O and δD to understand water balance in Lake Turkana, a large, low‐latitude, alkaline desert lake. The Omo River, a major river system in the Ethiopian Highlands, is historically understood to provide approximately 90% of the water input to Lake Turkana. Discharge of the Omo is prohibitively difficult to measure, but stable isotope ratios in the lake may provide a meaningful method for monitoring the lake's response to changes in input. Precipitation in the Turkana Basin is low (<200 mm/year) with negligible rainfall on the lake's surface, and all water loss from the lake is evaporative. We compare new measurements with previous data from the region and records of lake height and precipitation from the same time period. We show that a Bayesian approach to modeling evaporation using atmospheric conditions and river δ18O and δD yields results consistent with published water balance models. Continued sampling of lake and meteoric waters in the Turkana Basin will be a useful way to monitor the lake's response to regional and global climate change. Plain Language Summary: Lake Turkana is the largest desert lake in the world, in one of the hottest and driest places on Earth. Studying and preserving the lake are important because people and ecosystems depend on it, but information is lacking because it is remote and irregularly monitored. Most of the water in Lake Turkana comes from the Omo River, which flows through the Ethiopian Highlands. Lake Turkana has no outlet; therefore, evaporation is the only process that removes water from the lake. In this study, we analyzed samples of lake water as well as rain, river, surface, and ground waters and developed a model that uses measurements of oxygen and hydrogen stable isotopes in the water to help us understand how much evaporation occurs in Lake Turkana. Future lake water monitoring efforts should consider stable isotope methods to record how the basin hydrology responds to climate change. Key Points: New measurements of meteoric waters from the Turkana Basin in northern Kenya plot along the meteoric water lineA lake water evaporation line is developed using Bayesian modeling applied to a terminal lake mass balance modelThe model enables predictions of lake water δ values under past and future climate change scenarios [ABSTRACT FROM AUTHOR]

Contaminated lake water and fish can be sources of bacterial pathogens of public health concern, including pathogenic E. coli. Within Ethiopia, specifically, Central Oromia, raw fish consumption is a common practice. Although there are few reports on occurrence of E. coli O157 in fish destined for human consumption and children under five years, information on the transmission pathways of E. coli O157 and other sorbitol non-fermenting (SN-F) E. coli from water-to-fish-to-human, and their virulence factors and antimicrobial resistant determinants along the fish supply chain is lacking. The study aimed to investigate the occurrence, molecular characteristics, and antimicrobial susceptibility of E. coli O157 and other SN-F E. coli strains in fish, lake water and humans in central Oromia, Ethiopia. A total of 750 samples (450 fish samples, 150 water samples, 150 human stool samples) were collected from five lakes and three health facilities. The samples were processed following the standard protocol recommended by European Food Safety Authority and Kirby–Bauer disc diffusion method for detection of the bacteria, and antimicrobial susceptibility tests, respectively. Molecular characterization of presumptive isolates was performed using Whole-Genome Sequencing (WGS) for serotyping, determination of virulence factors, antimicrobial resistance traits, and genetic linkage of the isolates. Overall, 3.9% (29/750) of the samples had SN-F E. coli; of which 6.7% (n = 10), 1.8% (n = 8) and 7.3% (n = 11) were retrieved from water, fish, and diarrheic human patients, respectively. The WGS confirmed that all the isolates were SN-F non-O157: H7 E. coli strains. We reported two new E. coli strains with unknown O-antigen from fish and human samples. All the strains have multiple virulence factors and one or more genes encoding for them. Genetic relatedness was observed among strains from the same sources (water, fish, and humans). Most isolates were resistant to ampicillin (100%), tetracycline (100%), cefotaxime (100%), ceftazidime (100%), meropenem (100%), nalidixic acid (93.1%) and sulfamethoxazole/trimethoprim (79.3%). Majority of the strains were resistant to chloramphenicol (58.6%) and ciprofloxacin (48.3%), while small fraction showed resistance to azithromycin (3.45%). Isolates had an overall MDR profile of 87.5%. Majority, (62.1%; n = 18) of the strains had acquired MDR traits. Genes encoding for mutational resistance and Extended-spectrum beta-lactamases (ESBL) were also detected. In conclusion, our study revealed the occurrence of virulent and MDR SN-F E. coli strains in water, fish, and humans. Although no genetic relatedness was observed among strains from various sources, the genomic clustering among strains from the same sources strongly suggests the potential risk of transmission along the supply chain at the human–fish-environment interface if strict hygienic fish production is not in place. Further robust genetic study of the new strains with unknown O-antigens, and the epidemiology of SN-F E. coli is required to elucidate the molecular profile and public health implications of the pathogens. [ABSTRACT FROM AUTHOR]

This study utilizes a natural air diffusion cathode (ADC) and an ultraviolet lamp to construct a UV/H2O2 reactor for the in situ synthesis and activation of H2O2 and evaluates its potential application in practical lake water treatment. The results indicate that the reactor exhibits stable treatment performance during a continuous flow experiment of 80 h. The air diffusion cathode maintains an H2O2 concentration of above 350 mg·L−1 in sodium sulfate electrolyte and shows no decreasing trend. Under the condition of approximately 59% H2O2 utilization, the removal rates of COD and TOC are 37.6% and 40.0%, respectively; the rate of reduction of A254 is 64.3%; while the total bacterial count removal rate reaches 100%. Large organic molecules in surface water are degraded to small organic molecules and mineralized to inorganic minor molecules. It effectively ameliorates the problem of organic pollution of surface water and effectively kills bacteria and improves the microbiological safety of the water body. Therefore, the UV/H2O2 system developed in this study, based on electrochemically produced H2O2, is an effective method for treating micro-polluted surface water.

The freshwater ecosystem is deteriorating and becoming more polluted due to industrialization, urbanization, and increasing industries. This study is about the bacteriological and physicochemi-cal properties of the lake water in Gudiyattam town and its surroundings. For this research, samples of lake water from different locations were collected monthly during the period from May 2019 to April 2020 and analyzed based on standard procedures. The physicochemical parameters and bac-teriological analyses were studied for all four lakes (S1, S2, S3 and S4). The bacterial analysis results showed the presence of coliform bacteria in all lakes. The most dominant value of the MPN index for total coliform number was determined as 80,000 MPN/100mL, at S4 (Valathur) location during monsoon season. It is understood from the fecal coliform count that location S4 was again found to be dominant when compared to the other lakes, with a result of 8,500MPN/100mL in the mon-soon season. The possible reason for the high bacteriological values is thought to be the mixing of drainage waters into the lakes. The MPN value was higher in the monsoon season compared to the pre-monsoon season, which indicates that agricultural runoff occurs in the monsoon season. All the lakeswerecontaminatedwithbacterialpopulations,especiallyatlocationS4,whichneedsthemost attention among all the lakes. The above-selected lakes are major surveilling factors for hu-mans for various activities.

In this study, multiple remote sensing data were used to quantitatively evaluate the contributions of surface water, soil moisture and groundwater to terrestrial water storage (TWS) changes in five groundwater resources zones of Inner Mongolia (GW_I, GW_II, GW_III, GW_IV and GW_V), China. The results showed that TWS increased at the rate of 2.14 mm/a for GW_I, while it decreased at the rate of 4.62 mm/a, 5.89 mm/a, 2.79 mm/a and 2.62 mm/a for GW_II, GW_III, GW_IV and GW_V during 2003–2021. Inner Mongolia experienced a widespread soil moisture increase with the rate of 4.17 mm/a, 2.13 mm/a, 1.20 mm/a, 0.25 mm/a and 1.36 mm/a for the five regions, respectively. Significant decreases were detected for regional groundwater storage (GWS) with the rate of 2.21 mm/a, 6.76 mm/a, 6.87 mm/a, 3.01 mm/a, and 4.14 mm/a, respectively. Soil moisture was the major contributor to TWS changes in GW_I, which accounted 58% of the total TWS changes. Groundwater was the greatest contributor to TWS changes in other four regions, especially GWS changes, which accounted for 76% TWS changes in GW_IV. In addition, this study found that the role of surface water was notable for calculating regional GWS changes. [ABSTRACT FROM AUTHOR]

Lake water has been impaired with nutrients due to the synergic action of human-made activities and climate change. This situation is increasing eutrophication around the globe faster than before, causing water degradation, loss of its uses, and water-associated economic and health effects. Following the Sustainable Development Goal 6, more precisely its target 6.6, nations are already behind schedule in protecting and restoring water-related ecosystems (i.e., rivers and lakes). As concerns with eutrophication are escalating, eutrophic water remediation practices are the keys for restoring those lake waters. Diverse methodologies have been investigated focusing on the nutrient that limit primary productivity (i.e., phosphorus), but few have been applied to in-lake eutrophic water remediation. Thus, the objective of this paper is to provide an overview and critical comments on approaches and practices for facing eutrophic lake water remediation. Information on the successful cases and possible challenges/difficulties in the peer-reviewed literature are presented. This should be useful for supporting further remediation project selection by the stakeholders involved. In summary, for a successful and durable restoration project, external nutrient inputs need to be managed, followed by holistic and region-specific methods to attenuate internal legacy nutrients that are continually released into the water column from the sediment. When aligned well with stakeholder participation and continuous monitoring, these tools are the keys to long-lasting water restoration. [ABSTRACT FROM AUTHOR]

Data on concentrations of chemical elements and toxic substances in the water of lakes Valdayskoe (alkaline) and Gusinoe (acidic) and precipitation over 2015–2021 have been analyzed. Special attention is paid to the distribution of heavy metal ions and the concentration of benzo[a]pyrene in different seasons. Atmospheric precipitation in the region has been studied in detail as a possible indicator of transboundary transport. Using the HYSPLIT model, the trajectories of airflows to the study area have been constructed, and predominant sources of pollution have been estimated. Based on the literature data and the materials of Valday National Park, long-term (since 1985) trends in the chemical composition of the water have been analyzed. Geochemical and anthropogenic characteristics of the distribution of the selected chemical parameters in the water of the region have been considered, using statistical methods. [ABSTRACT FROM AUTHOR]

Understanding groundwater dynamics is important for projecting water resources of the Lake Kawaguchi, however, the difficulty of observation and the limited number of geochemical tracers are a problem. In this study, we investigated 14C concentration (Δ14C) of lake water for three years and employed a 14C box model to estimate the groundwater contribution. Seasonal variations of Δ14C were also observed in both 2019 and 2020, confirming that Δ14C in Lake Kawaguchi decreases from summer to fall and increases during winter. Heavy precipitation exceeding 300 mm in a few days because of tropical cyclon HAGIBIS (Typhoon#19) significantly increased Δ14C in the lake for one month and it could caused by temporal changes in the surface water pathway. The 14C box model demonstrated that 14C could semiquantitatively evaluate the groundwater flow in the lake. It is needed to add quantative evaluations inflow from rivers and other factors to understand of groundwater dynamics. [ABSTRACT FROM AUTHOR]

The freshwater ecosystem is deteriorating and becoming more polluted due to industrialization, urbanization, and increasing industries. This study is about the bacteriological and physicochemical properties of the lake water in Gudiyattam town and its surroundings. For this research, samples of lake water from different locations were collected monthly during the period from May 2019 to April 2020 and analyzed based on standard procedures. The physicochemical parameters and bacteriological analyses were studied for all four lakes (S1, S2, S3 and S4). The bacterial analysis results showed the presence of coliform bacteria in all lakes. The most dominant value of the MPN index for total coliform number was determined as 80,000 MPN/100mL, at S4 (Valathur) location during monsoon season. It is understood from the fecal coliform count that location S4 was again found to be dominant when compared to the other lakes, with a result of 8,500MPN/100mL in the monsoon season. The possible reason for the high bacteriological values is thought to be the mixing of drainage waters into the lakes. The MPN value was higher in the monsoon season compared to the pre-monsoon season, which indicates that agricultural runoff occurs in the monsoon season. All the lakes were contaminated with bacterial populations, especially at location S4, which needs the most attention among all the lakes. The above-selected lakes are major surveilling factors for humans for various activities. [ABSTRACT FROM AUTHOR]

Climate change and human actions will exacerbate eutrophication cases in inland waters. By external or internal inputs, there will be an increase in nutrient concentrations in those systems worldwide. Those nutrients will bring faster trophic changes to inland waters and possible health and recreational advisories. A novel approach using a floating filtration system, a silt curtain, and geotextiles (woven and non-woven) is under investigation. This method has been applied as an in-situ pilot experiment deployed at Lake Caron, a shallow eutrophic lake in Quebec, for two summers. Turbidity, total suspended solids (TSS), total phosphorus (TP), blue-green-algae-phycocyanin (BGA-PC) and chlorophyll-a showed statistically significant average removal efficiencies of 53%, 22%, 49%, 57% and 56%, respectively, in the first year and 17%, 36%, 18%, 34% and 32% in the second. Statistical correlations were found with TSS, turbidity and variables that could represent particles (TP, turbidity, chlorophyll-a). Employing this in situ management method could be a promising remediation for not only shallow lakes (average depth < 2 m) but also for ponds, rivers, coastal regions, bays and other water types, to enable cleaner water for future generations. [ABSTRACT FROM AUTHOR]

In the present study, a method is proposed for the determination of lead at trace levels by slotted quartz tube‐flame atomic absorption spectrophotometry (SQT‐FAAS) after preconcentration with stearic acid coated magnetic nanoparticle‐based dispersive solid phase extraction (SA‐MNP‐DSPE). The slotted quartz tube (SQT) is used to enhance the analyte atom residence time in the light path. Stearic acid coated magnetic iron oxide (Fe3O4) nanoparticles, which can be easily collected with an external magnet, are used as adsorbent in the extraction process. The limit of detection (LOD) and the limit of quantitation (LOQ) values of the proposed method are obtained as 0.90 and 2.9 µg L−1, respectively. The method allows high repeatability in a wide linear range between 5.0 and 250 µg L−1, and the relative standard deviation for six replicates is 5.8%. The detection power is enhanced by about 77‐fold compared to the regular flame atomic absorption spectrophotometry (FAAS) system. The method is validated by recovery experiments to four different lake water samples. After the spiking tests, good recovery results are calculated between 97% and 106%. These results show that lead can be detected at low levels in lake water samples with high sensitivity, accuracy, and precision. [ABSTRACT FROM AUTHOR]

Data on tritium monitoring near the city of Ozersk (Chelyabinsk oblast), which is affected by the Mayak Production Association, are presented. The results of the research have shown that the tritium concentration exceeds the technogenic background level established for the Ural region in almost all environments studied in the city of Ozersk and adjacent areas. The resulting data show the necessity of developing a method for processing tritium emissions and discharges from nuclear industry enterprises to reduce the risk for the population. [ABSTRACT FROM AUTHOR]

More than 150 lakes on different peninsulas and islands are situated in the Larsemann Hills. The Larsemann Hills is an ice-free area and are located halfway between the Vestfold Hills and the Amery Ice Shelf on the southeastern coast of Prydz Bay, Princess Elizabeth Land, and East Antarctica. During 34th Indian Scientific Expedition to Antarctica (ISEA) from 2014 to 2015, twenty lake water samples in triplicates were collected from the Broknes & Grovnes peninsula. Coliform and fecal coliform bacteria were analyzed in these samples. Out of twenty, eleven lake water samples were found to be contaminated with coliform bacteria. However, fecal coliform bacteria were absent in all the lake water samples. Coliforms are found in the lakes of Broknes peninsula (P2 Lake & P3 Lake) and Grovnes peninsula (L1C NG, L1D NG, L1E NG, L7 NG, L7A NG, L7B NG, L2 SG, L4 SG & L5 SG). Antarctic lakes water is being polluted due to anthropogenic activities caused by various research activities and tourism. The present study confirms the presence of coliform bacteria in the lakes of East Antarctica which indicates an alarming situation and needs to be investigated further. [ABSTRACT FROM AUTHOR]

In this Anthropocene period, due to high human interference for the developments in the fields of agriculture, industry and urban events, especially around lake water systems have affected significant changes in quality and quantity of the resources and enriched water with mineral nutrients, such as nitrogen and phosphorus as a consequence, lakes got enriched with increased algal productivity which in turn has led to oxygen depletion, recreational impairment, biodiversity loss and resulted in deterioration of habitat quality. The present study attempts to assess the water quality of Puttenahalli lake through phytoplankton studies. The Puttenahalli lake has been hysterically polluted by sewage discharge from two places, one from the underground drain in Nataraja layout and the other from an unknown source in the southern side which has led to a massive fish kill and organic load in the lake. The phytoplankton studies revealed the presence of harmful algal blooms like Spirogyra sp., Mycrocystis sp., Cylindrospermopsis sp., Arcella sp., Anabena sp., Scenedesmus sp., Ulothrix sp., Ankistrodesmus sp., Cosmarium sp., Trachelomonas sp., Zygnema sp., Navicula sp., Synedra sp., Cymbella sp., Nitzschia sp., Cyclotella sp., Selenastrum sp., diatoms sp., and many other cyanohabs were abundantly present in the studied lake. These Cyanobacterial blooms are currently a great threat to the ecological integrity and sustainability of lake water resources. [ABSTRACT FROM AUTHOR]

The cyanobacterial toxin saxitoxin (STX) is mainly associated with the blooms of marine dinoflagellates, but it is also produced by several species of freshwater cyanobacteria. So far, the degradation of STX has only been demonstrated by physicochemical treatments, but in this study, we demonstrated that natural factors, such as bacterioplankton and sunlight, had the capacity for degrading STX in the eutrophic Lake Arresø, Denmark. Natural lake bacterioplankton could reduce STX concentrations by 41–59%. A similar reduction was shown for four saxitoxin analogs. The exposure of the lake water to natural sunlight or simulated sunlight also reduced both intracellular and extracellular, dissolved STX. During 4–8 h exposure, natural sunlight reduced intracellular STX by 38–52% but increased extracellular, dissolved STX by 7–29%. Corresponding values for simulated sunlight were a reduction in intracellular STX by 16–45% and increased levels of extracellular STX by 10–33%. In particle-free lake water, the two types of sunlight reduced ambient, dissolved STX by 13–17%. The light exposure was observed to damage >94% of the sxtA gene involved in STX synthesis. This study demonstrated that lake water bacterioplankton and sunlight can modify STX by degradation and cell destruction, and that the biosynthesis of STX may be inhibited by exposure to sunlight. [ABSTRACT FROM AUTHOR]

Aerobic anoxygenic photosynthetic bacteria (AAPB) are a kind of heterotrophic prokaryote that can use bacteriochlorophyll (BChl) for photosynthesis without oxygen production and they are widely distributed in aquatic environments, including oceans, lakes, and rivers. A novel aerobic anoxygenic photosynthetic bacterium strain XJSPT was isolated during a study of water microbial diversity in Sayram Lake, Xinjiang Province, China. Strain XJSPT was found to grow optimally at 33 °C, pH 7.5 with 1.0% (w/v) NaCl, and to produce bacteriochlorophyll a and carotenoids. Phylogenetic analysis based on 16S rRNA gene sequence and concatenated alignment sequences of 120 ubiquitous single-copy proteins both supported that strain XJSPT belonged to the genus Pseudotabrizicola. Both average nucleotide identity (ANI) and DNA–DNA hybridization (DDH) values were below the species delineation threshold. The primary polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, one unknown lipid, and one unidentified phospholipid. Based on the results of polyphasic analyses performed in this study, strain XJSPT represents a new member of the genus Pseudotabrizicola, for which the name Pseudotabrizicola formosa sp. nov. is proposed. The type strain is XJSPT (= KCTC 52636T = MCCC 1H00184T = SDUM 107003T). Comparative genomic analysis showed that four species of the genus Pseudotabrizicola shared 2570 core genes and possessed a complete anoxygenic photosystem II. [ABSTRACT FROM AUTHOR]

In this study, C-dots were facilely synthesized via microwave irradiation using citric acid and ethylenediamine as carbon precursors. The fluorescence emissions of the C-dots could be selectively quenched by Fe3+, and the degree of quenching was linearly related to the concentrations of Fe3+ presented. This phenomenon was utilized to develop a sensitive fluorescence assay for Fe3+ detection with broad linear range (0–250, 250–1200 μmol/L) and low detection limit (1.68 μmol/L). Most importantly, the assay demonstrated high reliability towards samples in deionized water, tap water and lake water, which should find potential applications for Fe3+ monitoring in complicated environments. [ABSTRACT FROM AUTHOR]

In this study, multiple remote sensing data were used to quantitatively evaluate the contributions of surface water, soil moisture and groundwater to terrestrial water storage (TWS) changes in five groundwater resources zones of Inner Mongolia (GW_I, GW_II, GW_III, GW_IV and GW_V), China. The results showed that TWS increased at the rate of 2.14 mm/a for GW_I, while it decreased at the rate of 4.62 mm/a, 5.89 mm/a, 2.79 mm/a and 2.62 mm/a for GW_II, GW_III, GW_IV and GW_V during 2003–2021. Inner Mongolia experienced a widespread soil moisture increase with the rate of 4.17 mm/a, 2.13 mm/a, 1.20 mm/a, 0.25 mm/a and 1.36 mm/a for the five regions, respectively. Significant decreases were detected for regional groundwater storage (GWS) with the rate of 2.21 mm/a, 6.76 mm/a, 6.87 mm/a, 3.01 mm/a, and 4.14 mm/a, respectively. Soil moisture was the major contributor to TWS changes in GW_I, which accounted 58% of the total TWS changes. Groundwater was the greatest contributor to TWS changes in other four regions, especially GWS changes, which accounted for 76% TWS changes in GW_IV. In addition, this study found that the role of surface water was notable for calculating regional GWS changes.

Chlorophyll-a (Chl-a) is an important index in water quality assessment by remote sensing technology. For the study of Chl-a value measurement in rivers or lakes, there are many classical methods, such as curve fitting, back propagation (BP) neural network and radial basis function (RBF) neural network, and all of them have some corresponding applications. With the rise of computer power and deep learning, this study intended to analyze the measurement of water quality and Chl-a in deep learning (DL) and to compare it with several classical methods, so as to explore and develop better methods. Taking Taihu Lake of China as the case, this study adopted the measured data of Chl-a in Taihu Lake in 2017 and the data corresponding to the same time from Landsat8. In this study, the four methods were used to invert the distribution of the Chl-a value in Taihu Lake. From the results of inversion, the power curve fitting model with ∑Residual2 of fitting of 90.469 and inverse curve fitting model with the ∑Residual2 of fitting of 602,156.608 had better results than the other curve fitting models; however, they were not as accurate as the machine learning method from segmentation results images. The machine learning method had better accuracy than the curve fitting methods from segmentation results images. The mean squared error of testing of the three methods of machine learning (BP, RBF, DL) were respectively 1.436, 4.479, 4.356. Thus, the BP method and DL method had better results in this study. HIGHLIGHTS BP had the best results, and DNN also had nice mean squared error of results.; In the future, the data volume and equipment condition need to be discussed to choose the optimal method.; The machine learning method had less error than the curve fitting methods.;

The effects of the present global climate change appear more pronounced in high latitudes and alpine regions. Transitions zones, such as the southern fringe of the boreal region in northern Mongolia, are expected to experience drastic changes as a result. This area is dry and cold with forests forming only on the north-facing slopes of hills and grasslands distributing on the south-facing slopes, making it difficult for continuous forests to exist. However, in the Hovsgol Lake Basin, there is a vast continuous pure forest of Siberian larch (Larix sibirica). In other words, the lake water thawing/freezing process may have created a unique climatic environment that differs with the climate of the adjacent Darhad Basin, where no lake exists. Thus, in order to compare the effect of the thawing/freezing dynamics of lake water and the active layer on the thermal regime at each basin, respectively, temperatures were simultaneously measured. The Darhad Basin has similar latitude, topography, area, and elevation conditions. As expected, the presence of the lake affected the annual temperature amplitude, as it was 60% of that in the Darhad Basin. The difference in the seasonal freeze–thaw cycles of the lake and the active layer caused a significant difference in the thermal regime, especially in winter. [ABSTRACT FROM AUTHOR]

At certain nutrient concentrations, shallow freshwater lakes are generally characterized by two contrasting ecological regimes with disparate patterns of biodiversity and biogeochemical cycles: a macrophyte-dominated regime (MDR) and a phytoplankton-dominated regime (PDR). To reveal ecological mechanisms that affect bacterioplankton along the regime shift, Illumina MiSeq sequencing of the 16S rRNA gene combined with a novel network clustering tool (Manta) were used to identify patterns of bacterioplankton community composition across the regime shift in Taihu Lake, China. Marked divergence in the composition and ecological assembly processes of bacterioplankton community was observed under the regime shift. The alpha diversity of the bacterioplankton community consistently and continuously decreased with the regime shift from MDR to PDR, while the beta diversity presents differently. Moreover, as the regime shifted from MDR to PDR, the contribution of deterministic processes (such as environmental selection) to the assembly of bacterioplankton community initially decreased and then increased again as regime shift from MDR to PDR, most likely as a consequence of differences in nutrient concentration. The topological properties, including modularity, transitivity and network diameter, of the bacterioplankton co-occurrence networks changed along the regime shift, and the co-occurrences among species changed in structure and were significantly shaped by the environmental variables along the regime transition from MDR to PDR. The divergent environmental state of the regimes with diverse nutritional status may be the most important factor that contributes to the dissimilarity of bacterioplankton community composition along the regime shift. [ABSTRACT FROM AUTHOR]

Water quality indices (WQIs) are practical and versatile instruments for assessing, organizing, and disseminating information about the overall quality status of surface water bodies. The use of these indices may be beneficial in evaluating aquatic system water quality. The CCME (Canadian Council of Ministers of the Environment) and NSF (National Science Foundation) WQIs were used for the assessment of surface water (depth = 1 m) in Lake Union, Washington State. These WQIs were used in surface water at Lake Union, Seattle. The modified versions of the applied WQIs incorporate a varied number of the investigated parameters. The two WQIs were implemented utilizing specialized, publicly accessible software tools. A comparison of their performance is offered, along with a qualitative assessment of their appropriateness for describing the quality of a surface water body. Practical conclusions were generated and addressed based on the applicability and disadvantages of the evaluated indexes. When compared to the CCME-WQI, it is found that the NSF-WQI is a more robust index that yields a categorization stricter than CCME-WQI. [ABSTRACT FROM AUTHOR]

The neurotoxic alkaloid β-N-methyl-amino-l-alanine (BMAA) and related isomers, including N-(2-aminoethyl glycine) (AEG), β-amino-N-methyl alanine (BAMA), and 2,4-diaminobutyric acid (DAB), have been reported previously in cyanobacterial samples. However, there are conflicting reports regarding their occurrence in surface waters. In this study, we evaluated the impact of amending lake water samples with trichloroacetic acid (0.1 M TCA) on the detection of BMAA isomers, compared with pre-existing protocols. A sensitive instrumental method was enlisted for the survey, with limits of detection in the range of 5–10 ng L−1. Higher detection rates and significantly greater levels (paired Wilcoxon's signed-rank tests, p < 0.001) of BMAA isomers were observed in TCA-amended samples (method B) compared to samples without TCA (method A). The overall range of B/A ratios was 0.67–8.25 for AEG (up to +725%) and 0.69–15.5 for DAB (up to +1450%), with absolute concentration increases in TCA-amended samples of up to +15,000 ng L−1 for AEG and +650 ng L−1 for DAB. We also documented the trends in the occurrence of BMAA isomers for a large breadth of field-collected lakes from Brazil, Canada, France, Mexico, and the United Kingdom. Data gathered during this overarching campaign (overall, n = 390 within 45 lake sampling sites) indicated frequent detections of AEG and DAB isomers, with detection rates of 30% and 43% and maximum levels of 19,000 ng L−1 and 1100 ng L−1, respectively. In contrast, BAMA was found in less than 8% of the water samples, and BMAA was not found in any sample. These results support the analyses of free-living cyanobacteria, wherein BMAA was often reported at concentrations of 2–4 orders of magnitude lower than AEG and DAB. Seasonal measurements conducted at two bloom-impacted lakes indicated limited correlations of BMAA isomers with total microcystins or chlorophyll-a, which deserves further investigation. [ABSTRACT FROM AUTHOR]

The present work is first of its kind to attempt on year-round biogas production utilizing microalgal biomass from lake water. The analyses showed that the lake water contain ample nutrients (TAN: 3.6–16; TDP: 4.88–20.38 and NO3-N: 0.3–19.63 mg L−1) to support microalgal growth, with an average biomass concentration of ≈ 2.0 g L−1, throughout the year. Significant correlation (p < 0.05) was observed between microalgal biomass and nutrient concentration in the lake water. Further, co-digestion studies in the pilot-scale plant (0.5 m3) showed good performance with a volumetric and specific biogas yield in the range of 0.45 to 0.65 m3 day−1 and 0.72 to 1.04 m3 kg−1 VSfed day−1 respectively, during the summer. However, during winters, the volumetric and specific biogas yield were found to be in the range of 0.06 and 0.21 m3 day−1 and 0.096–0.336 m3 kg−1 VSfed day−1, respectively, with an average 55–65% CH4. Detailed analyses of digestate indicated long-term stability of the pilot-scale process. This study established the feasibility of utilizing waste algal biomass from eutrophic lake water for year-round biogas production. [ABSTRACT FROM AUTHOR]

[Display omitted] • A flexible and cost-effective SERS sensor is created utilizing fish scales as a template. • The resulting SERS substrate exhibits notable porosity and wettability, promoting the formation of densely packed hotspots. • An impressive SERS enhancement factor of 1.3 × 106 is achieved, with a relative standard deviation of 6.4 %. • Demonstrations of fish scale substrates in detecting harmful environmental pollutant perfluorooctane sulfonamide in lake water, soil, and human urine samples are presented. Biological materials with unique surface properties provide a new avenue for fabricating green and sensitive SERS-active substrates. Herein, we present a simple but efficient method to prepare surface-enhanced Raman scattering (SERS) substrates by depositing silver nanoparticles (AgNPs) on fish scale substrates using an evaporation-induced self-assembly method (EISA). Characterization of the formed flexible Ag-impregnated substrate proved outstanding SERS sensitivity, uniformity, and reproducibility properties, with a Raman enhancement factor of 1.3 × 106 and a relative standard deviation of 6.4 %. Using this powerful fish scale substrate, a toxic environmental pollutant perfluorooctane sulfonamide (PFOSA) was indirectly detected in lake water, soil, and human urine samples. Due to its chemical structure, it is difficult to detect low concentrations of PFOSA in real samples. Interestingly, malachite green (MG) was smartly used as the Raman label for PFOSA detection in real samples. One of the main appeals is that the concentration of PFOSA can be correlated with a decrease in the SERS signal of MG in real samples. In conclusion, the strategy employed and reproducible SERS substrates may have diverse applications in clinical and environmental analyses. [ABSTRACT FROM AUTHOR]

Since the beginning of the industrial revolution in the nineteenth century water pollution has grown into a global transboundary problem that negatively impacts aquatic ecosystems a risk linked directly to sustainable economic development, human, aquatic, and wildlife health. However, one major impediment to monitoring lake water quality is a lack of data for the relevant monitoring parameters at the relevant temporal and spatial scales. Therefore, this study investigates sixteen major reservoirs on a national scale based on 2020 in-situ sampling and Sentinel-2 MSI satellite data. Machine and deep learning algorithms were employed to classify and predict various water quality classes using Sentinel-2 MSI pixel color values and spectral indices. Multivariate techniques such as PCA transformation and regularized MANOVA were used as input feature preprocessing for variable reconstruction to deal with collinearity. Consequently, this improved the model classification performances overall. The results highlight deep neural net (DNN) and XGBoost as the outstanding classifying algorithms yielding F1-score of 0.94 and 0.93; Recall of 0.93 and 0.92; ROC-AUC of 0.92 and 0.89 respectively. Nutrient pollution affects all of the investigated reservoirs as they are classified as either meso- or hypereutrophic, and the situation is deteriorating. This study does not only give a feasible solution for effective water quality observation, but also provides a unique data pipeline for basic creation of training data for biogeochemical parameters for studying lake water quality using an integrated Google Earth Engine (GEE) Python Application Programming Interface (API) run in Google Colaboratory notebook. [Display omitted] • Exceptional performances of DNN and XGBoost in monitoring eutrophication. • High spatial resolution of Sentinel-2 enables accurate eutrophication monitoring. • Data engineering and transformation improve model performance. • GEE/Python API pipeline solution to overcome labeled data insufficiency. [ABSTRACT FROM AUTHOR]

The reasonable utilization of water resources and real-time monitoring of water pollution are the core tasks of current world hydrological and water conservancy work. Novel technologies and methods for monitoring water pollution are important means to ensure water health. However, the absence of intuitive and simple analysis methods for the assessment of regional pollution in large-scale water bodies has prevented scientists from quickly grasping the overall situation of water pollution. In this study, we propose a strategy based on the unique combination of fluorescence technology and simple kriging (SK) interpolation (FL-SK) for the first time. This strategy could present the relative magnitude and distribution of the physicochemical indicators of a whole natural lake intuitively and accurately. The unique FL-SK model firstly offers a simple and effective water quality method that provides the pollution index of different sampling points in lakes. The macroscopic evaluation of large-scale water bodies by the FL-SK model primarily relies on the fluorescence response of the RDM-TPE to the comprehensive indicators of the water body, as experimental results have revealed a good correlation between fluorescent responses and six normalized physicochemical indicators. Multiple linear regression and fluorescence response experiments on RDM-TPE indicate that to some extent, the fluorescence signals of the FL-SK model may originate from a certain type of sulfide in the water body. Pattern discovery could enable the analysis of pollution levels in other ecosystems and promote early pollution assessment in the future. [Display omitted] • We developed a unique combination mode FL–SK for the first time. • The FL-SK mode could present pollution levels in natural water intuitively and accurately. • The evaluation of water bodies by FL-SK mainly relies on the fluorescence data of RDM-TPE. • Pattern discovery could enable the analysis of pollution levels in other ecosystems. [ABSTRACT FROM AUTHOR]

Long-lasting chemiluminescence of lucigenin/p-aminophenol (4-AP) system is explored for the first time and possible chemiluminescence enhancement mechanism is also proposed in this work. 4-AP can enhance chemiluminescence of lucigenin nearly 150 times and is stable for nearly 5 min, which overcomes the need of flow syringe pump. While o-aminophenol (2-AP) slightly enhances chemiluminescence of lucigenin and m-aminophenol (3-AP) does not. Thus, it can be applied in discrimination of three aminophenol isomers. More importantly, cyclic voltammetry proves the lowest oxidation peak for 4-AP at 115 mV, which is speculated to be the main reason for 4-AP induced chemiluminescence enhancement. It has been applied in chemiluminescence enhancement detection of 4-AP and p-nitrophenol (4-NP) from 80 nM to 60 μM, from 0.5 μM to 60 μM with limit of detection (LOD) of 26 nM and 0.17 μM, respectively. It shows high selectivity and anti-interference in chemiluminescence enhancment detection of 4-AP and 4-NP towards other organic compounds and metal ions. It also exhibits high accuracy in chemiluminescence enhancment detection of 4-AP and 4-NP in lake water with recoveries from 98.7% to 101.5% for and recoveries from 98.7% to 102.2%, respectively. It expands the study of long-lasting lucigenin chemiluminescence system and chemiluminescence method utilized in discrimination of aminophenols isomers. Long-lasting chemiluminescence of lucigenin/p-aminophenol (4-AP) system is explored for the first time. 4-AP enhances chemiluminescence of lucigenin nearly 150 times, which can be stable for nearly 5 min. It is applied in chemiluminescence enhancment detection of 4-AP with LOD of 26 nM and fast discrimination of three aminophenol isomers (2-AP, 3-AP and 4-AP). [Display omitted] • Chemiluminescence detection of 4-AP from 80 nM to 60 μM and p-nitrophenol from 0.5 μM to 60 μM. • Long-lasting chemiluminescence of lucigenin/p-aminophenol (4-AP) system is firstly developed. • 4-AP enhances chemiluminescence of lucigenin nearly 150 times, which can be stable for nearly 5 min. [ABSTRACT FROM AUTHOR]

A novel Gram-negative strain, designated X100-76T, was isolated from Daihai Lake in Inner Mongolia, Republic of China. The strain was non-motile, non-spore-forming, long-rod-shaped, oxidase positive and catalase positive. Colonies incubated at 33 °C on 2216 marine agar medium for 3 days were circular, smooth, transparent, convex with clear edges, orange-red in colour and approximately 1.0 mm in diameter. Growth occurred at pH 6.5–12 (optimum pH 7.5), in 0–5.0% (w/v) NaCl (optimum 1.5%, w/v) and at 4–40 °C (optimum 28–33 °C). Phylogenetic analysis based on 16S rRNA gene sequences showed that X100-76T belongs to the genus Mongoliitalea and is most closely related to Mongoliitalea lutea MIM18T with 98.3% sequence similarity. The total genome size of X100-76T was 4,816,617 bp with a G + C content of 39.6%. The digital DNA–DNA hybridization and average nucleotide identity values between strain X100-76T and M. lutea MIM18T were both below the recommended cut-off values. Chemotaxonomic analysis revealed iso-C15:0, Sum Feature 4 (anteiso-C17:1 B and/or iso-C17:1 I), C15:1ω6c, Sum Feature 9 (C16:0 10-methyl and/or iso-C17:1ω9c), C16:0 and iso-C15:1 G as the major fatty acids, menaquinone MK-7 as the major isoprenoid quinone, diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and phosphatidylinositol as the major cellular polar lipids. The results of polyphasic analysis demonstrated that X100-76T represents a novel species within the genus Mongoliitalea, for which the name Mongoliitalea daihaiensis sp. nov. is proposed. The type strain is X100-76T (= CGMCC 1.18762T = KCTC 82458T). [ABSTRACT FROM AUTHOR]

Shallow groundwater and lake water are the dominant water resources in the Badain Jaran Desert. There are still controversial hypotheses related to the origin of groundwater in this desert. Few studies have been conducted to explore the Sr provenance of these waters and assess the water–rock interactions using a Sr isotope approach until now. In this text, the Sr isotope data of waters in the hinterland of the Badain Jaran Desert and neighbouring areas are reported. The waters in the Badain Jaran Desert have few links to its surrounding rivers, but could be influenced by the precipitation in the Yabulai Mountains. The 87Sr/86Sr ratio changes constantly, while the Sr2+ concentration of shallow groundwater gradually decreases from Yabulai to the desert hinterland to Gurinai-Guaizihu. Combined with hydrochemical data and hydrodynamic conditions, these results show that the dissolved Sr of waters in the desert hinterland is controlled by the Yabulai precipitation and catchment weathering. They further show that the desert shallow groundwater Sr originates mainly from the Yabulai precipitation (> 94 %), while whole-rock weathering contributes little (< 6 %), as calculated using isotope mass balance equations. Relative Sr contributions to lakes from shallow groundwater and catchment weathering are calculated to be 92.5 and 7.5 %, respectively. [ABSTRACT FROM AUTHOR]

This review presents a compilation of pharmaceuticals and personal care products (PPCPs) that have been detected in waters, sediments and biota of lakes throughout the world by various researchers, over a 26-year time period (1996–2021). Numerous studies published in the literature reported that 286 pharmaceuticals and 70 personal care products (PCPs) were present in waters, 101 pharmaceuticals and 50 PCPs were present in sediments, and 63 pharmaceuticals and 19 PCPs were present in biota of lakes throughout the world. Among the pharmaceuticals present in lake waters, 194 had concentrations of over 5 ng/L, 173 were present in only one continent, whereas several (e.g. caffeine, carbamazepine and sulfamethoxazole) were detected in lake waters of almost every continent (6/7). Among the PCPs present in lake waters, 56 had concentrations of over 5 ng/L, whereas 41 were present in only one continent. PPCPs were found in 260 lakes, located within 44 countries, the majority of them present in Asian, European and North American lakes. Lakes with high pharmaceutical concentrations were affected by either controlled or uncontrolled wastewater originated from various types of sources. Based on this study, of high concern is the Asian continent, where PPCP pollution should be strictly controlled in order to prevent possible serious health threats to humans and living organisms.

The cyanobacterial toxin saxitoxin (STX) is mainly associated with the blooms of marine dinoflagellates, but it is also produced by several species of freshwater cyanobacteria. So far, the degradation of STX has only been demonstrated by physicochemical treatments, but in this study, we demonstrated that natural factors, such as bacterioplankton and sunlight, had the capacity for degrading STX in the eutrophic Lake Arresø, Denmark. Natural lake bacterioplankton could reduce STX concentrations by 41–59%. A similar reduction was shown for four saxitoxin analogs. The exposure of the lake water to natural sunlight or simulated sunlight also reduced both intracellular and extracellular, dissolved STX. During 4–8 h exposure, natural sunlight reduced intracellular STX by 38–52% but increased extracellular, dissolved STX by 7–29%. Corresponding values for simulated sunlight were a reduction in intracellular STX by 16–45% and increased levels of extracellular STX by 10–33%. In particle-free lake water, the two types of sunlight reduced ambient, dissolved STX by 13–17%. The light exposure was observed to damage >94% of the sxtA gene involved in STX synthesis. This study demonstrated that lake water bacterioplankton and sunlight can modify STX by degradation and cell destruction, and that the biosynthesis of STX may be inhibited by exposure to sunlight.

Aerobic anoxygenic photosynthetic bacteria (AAPB) are a kind of heterotrophic prokaryote that can use bacteriochlorophyll (BChl) for photosynthesis without oxygen production and they are widely distributed in aquatic environments, including oceans, lakes, and rivers. A novel aerobic anoxygenic photosynthetic bacterium strain XJSPT was isolated during a study of water microbial diversity in Sayram Lake, Xinjiang Province, China. Strain XJSPT was found to grow optimally at 33 °C, pH 7.5 with 1.0% (w/v) NaCl, and to produce bacteriochlorophyll a and carotenoids. Phylogenetic analysis based on 16S rRNA gene sequence and concatenated alignment sequences of 120 ubiquitous single-copy proteins both supported that strain XJSPT belonged to the genus Pseudotabrizicola. Both average nucleotide identity (ANI) and DNA–DNA hybridization (DDH) values were below the species delineation threshold. The primary polar lipids were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, one unknown lipid, and one unidentified phospholipid. Based on the results of polyphasic analyses performed in this study, strain XJSPT represents a new member of the genus Pseudotabrizicola, for which the name Pseudotabrizicola formosa sp. nov. is proposed. The type strain is XJSPT (= KCTC 52636T = MCCC 1H00184T = SDUM 107003T). Comparative genomic analysis showed that four species of the genus Pseudotabrizicola shared 2570 core genes and possessed a complete anoxygenic photosystem II.

In this study, C-dots were facilely synthesized via microwave irradiation using citric acid and ethylenediamine as carbon precursors. The fluorescence emissions of the C-dots could be selectively quenched by Fe3+, and the degree of quenching was linearly related to the concentrations of Fe3+ presented. This phenomenon was utilized to develop a sensitive fluorescence assay for Fe3+ detection with broad linear range (0–250, 250–1200 μmol/L) and low detection limit (1.68 μmol/L). Most importantly, the assay demonstrated high reliability towards samples in deionized water, tap water and lake water, which should find potential applications for Fe3+ monitoring in complicated environments.

Water quality assessment was carried out at Indawgyi Lake, the biggest lake of Myanmar. The main aim of this research is to evaluate the current status of lake water quality affected by the surroundings and man-made activities for three seasons (cold, hot and rainy) in 2019. Some physicochemical properties such as temperature, pH, ORP, EC, NTU, TDS and DO of surface and deep water samples from each point and totally four different points were analyzed in situ by water quality monitor U-53-G(Horiba). The concentrations of Cr, Mn, Fe, Cu, As and Hg were also examined by atomic absorption spectrometer (AAS) and total hardness, total alkalinity, salinity and chloride were measured by their respective methods. Nitrate and phosphate were detected by LaMotte, SMART 3 colorimeter. The condition of COD and BOD of the lake water were also investigated by standard incubating methods. In addition, counting of coliform was performed to detect pathogenic microorganisms of lake water. The resulting values were compared with the standard limits of World Health Organization (WHO) and it was concluded that the lake was urgently needed to sustain the long-life existence and its water qualities due to the findings of some physicochemical, biological, toxic and pathogenic affects produced by the surroundings. [ABSTRACT FROM AUTHOR]

Though having an economic and ecological impact on Marriott Lake management in Egypt, water hyacinth (Eichhornia crassipes) is an aquatic floating macrophyte with a known phytoremediation potential. In order to assess its remediation potential, pilot floating treatment wetlands (FTWs) with E. crassipes were built in duplicates to evaluate the removal of nutrients and heavy metals from the polluted lake water. The experimental design included units with different water depths (15, 25, and 35 cm; D15, D25, and D35, respectively) and plant coverage (90, 70, 50, and 0%; P90, P70, P50, and P0, respectively). The pilot FTWs were monitored over a 7-day operation cycle to identify the optimum combination of design (plant coverage, water depth) and operation (hydraulic retention time; HRT) parameters needed for maximum BOD5, TN, NH4-N, and TP removal. NH4-N removal reached 97.4% in the D25P50 unit after 3 days, BOD5 75% in the D15P90 after 3 days, TN 82% in the D25P70 after 4 days, and TP 84.2% in the D35P70 after 4 days. The open-water evaporation rate was higher than the evapotranspiration rate in the planted units, probably due to the warm climate of the study area. Metals were also sufficiently removed through bioaccumulation in plant tissues in the order of Fe > Pb > Cu > Ni (62.5%, 88.9%, 81.7%, and 80.4% for D25P50, D25P70, D25P50, and D25P90, respectively), while most of the assimilated metal mass was translocated to the plant roots. The biochemical composition of the plant tissue was significantly different between the shoot and root parts. Overall, the FTW with 70% E. crassipes coverage, 25-cm water depth, and an HRT of 3–5 days was identified as the optimum design for effective remediation of the polluted Marriott Lake in Egypt. [ABSTRACT FROM AUTHOR]

Shah Alam is in Selangor, Malaysia and symbolized with several lakes that are popular among local communities and visitors for leisure and recreational activities. Among of these lakes, few lakes need management to look after its hygienic and well-being to serve its purpose as the recreational lake for the nearby community, such as Lake 7/1F, Shah Alam, Selangor. The secluded location of this water reservoir has made it unpopular, and improper management of it could invite an imbalance environment to its surrounding. Therefore, to initiate the effort, an Internet-of-Thing (IoT) water monitoring system is deployed at this lake to study the dissolved oxygen (DO) level in the water that could indicate the health status of this lake. The system consists of a DO sensor, embedded controller, self-charging power supply, wireless data transmission, and IoT dashboard for in-situ DO measurement. From the analysis, the lake has the normal cycle of DO production, but a dangerous condition is detected when the concentrated DO in the lake water is mostly below the saturation value. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ag@ZIF-8@Au was proposed for tracing acetamiprid by SERS in environment. • The electrostatic interaction from AgNPs and AuNPs provided a lot of hotspots. • ZIF-8 emended in Ag@ZIF-8@Au can enrich analyte molecules in hotspots areas. • The SERS platform exhibited high sensitivity, stability and reproducibility. • The limit of detection for acetamiprid was as low as 9.027 × 10-10 M. The unreasonable spraying and random migration of acetamiprid may cause pollution of crops, soil and water resources in the environment, resulting in threatening ecosystem and human health. However, the monitoring of acetamiprid using mass spectrum in the environment encounters challenges due to high-cost instruments and complex processing time. Herein, we fabricated a rapid and reliable SERS method based on Ag@ZIF-8@Au platforms for tracing acetamiprid residues in the environment. In this method, a MOF material named ZIF-8 is coated with silver nanoparticles and distributed internally between AgNPs and AuNPs to enhance Raman signal, which can enrich pesticide molecules into the hotspots area provided by noble material and helps avoid the oxidation of silver nanoparticles. High sensitivity (LOD of 9.027 × 10-10 M for acetamiprid, and SERS enhancement factor of 4.3 × 107), excellent reproducibility (6.496% or 7.198% RSD for 30 random points) and superior stability (3.127% RSD for 6 weeks) were achieved using the proposed method. Acetamiprid with concentrations from 10-4 to 10-9 M were successfully detected by SERS method. Furthermore, the linear detection models of acetamiprid in different environment matrices (lake water, tea leaves, tea garden soil, oranges and oranges orchard soil) were established and all the correlation coefficient (R2) were higher than or equal to 95%, indicating the excellent adaptability of Ag@ZIF-8@Au platform in environment. The randomly spiked concentrations of acetamiprid were also tested with good recovery values and low relative error values, further confirming the reliability of the detection method. [ABSTRACT FROM AUTHOR]

Underwater concrete finds application in many underwater structures, such as port facilities, bridge footings, tunnels, and analogous infrastructural elements. In recent years, a growing significance has been attributed to the investigation of sustainable geopolymer studies conducted on land. Hence, the necessity of researching underwater sustainable geopolymer composites emerged. This study produced metakaolin and slag-based geopolymer paste samples containing carbon nanotubes (CNTs) cast and cured in a dry environment, lake water, and seawater. Also, the present work examined the relation between CNTs and metakaolin and slag-based geopolymers in the context of underwater cast and curing. In order to achieve the intended objective, geopolymer samples with CNTs at 0%, 0.05%, 0.15%, and 0.25% ratios poured in under three distinct environments were prepared and subjected to various tests. Subsequently, examinations were conducted to determine the mechanical and microstructural characteristics of the geopolymer samples poured in the three environments. The conducted tests encompassed compressive strength assessment, temperature measurements, pH measurements, and microstructural analyses. Consequently, the compressive strength of the 0.25% CNT geopolymer samples increased by 32.7% and 34.4% compared to the CNT free-geopolymer samples poured in lake water and seawater, respectively. Thus, in this study, underwater geopolymer samples with compressive strengths of 46 MPa and 49.6 MPa were produced in lake water and seawater, respectively. • Production of metakaolin and slag based underwater geopolymer. • Incorporation the CNTs in the underwater geopolymer. • Investigation the effect of CNTs on the underwater geopolymer. • Comparison of the behavior of geopolymers cast in dry environment, lake water and seawater. • CNTs successfully improved the mechanical properties of underwater geopolymer. [ABSTRACT FROM AUTHOR]