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22 pages, 1973 KiB  
Article
Chemical Ecology, Detection and Identification of Subterranean Termites Based on Electronic-Nose Volatile Emissions Analysis
Environments 2024, 11(1), 15; https://doi.org/10.3390/environments11010015 - 13 Jan 2024
Viewed by 182
Abstract
The effective monitoring and identification of existing subterranean termite populations within coarse woody debris and infested wood in service depend on accurate detection. These insects are often concealed within logs, wooden support structures, walls, and floorboards of buildings. In the absence of external [...] Read more.
The effective monitoring and identification of existing subterranean termite populations within coarse woody debris and infested wood in service depend on accurate detection. These insects are often concealed within logs, wooden support structures, walls, and floorboards of buildings. In the absence of external mud tubes, termite infestations normally must be discovered through the destructive exploration of wooden structures to reveal the physical presence of these insect pests. Subterranean termite species are difficult to identify due to similarities in morphological features, but they may be readily distinguished by differences in volatile emissions from which they are divided into chemotaxonomic groups. Consequently, a more effective and nondestructive approach for detection and identification is to take advantage of unique species-specific emissions of volatile organic compounds (VOCs) from termite bodies which easily pass through wooden structures, allowing for detection without physical damage to wood and avoiding expensive DNA analysis. Electronic aroma detection analyses were conducted with an Aromascan A32S electronic-nose (e-nose) instrument, fitted with a 32-sensor conducting polymer (CP) sensor array, for discrimination between four common subterranean termite species based on differences in volatile emissions. Principal component analysis (PCA) of whole-body volatiles effectively distinguished between four termite species with the first two principal components accounting for more than 98% of sample variance (p < 0.01). Unique electronic aroma signature patterns (smellprints) were produced from e-nose sensor array outputs that allowed for the effective identification of termite species based on distinct differences in volatile metabolites released from their bodies. The e-nose methods were determined to be an improved means for rapidly detecting and monitoring termite species in wood. The method is cheaper than conventional detection methods and allows for the timelier discovery of species-specific termite infestations necessary for better management. The e-nose capability of detecting the Formosan termite in indoor living spaces was particularly significant due to the production of naphthalene, a volatile hazardous gas causing many adverse human health effects in enclosed environments. Full article
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15 pages, 1869 KiB  
Article
Co-Valorisation Energy Potential of Wastewater Treatment Sludge and Agroforestry Waste
Environments 2024, 11(1), 14; https://doi.org/10.3390/environments11010014 - 09 Jan 2024
Viewed by 313
Abstract
The growing demand for sustainable and environment-friendly energy sources resulted in extensive research in the field of renewable energy. Biomass, derived from organic materials such as agricultural waste, forestry products, and wastewater treatment plant (WWTP) sludge, holds great potential as a renewable energy [...] Read more.
The growing demand for sustainable and environment-friendly energy sources resulted in extensive research in the field of renewable energy. Biomass, derived from organic materials such as agricultural waste, forestry products, and wastewater treatment plant (WWTP) sludge, holds great potential as a renewable energy resource that can reduce greenhouse gas emissions and offer sustainable solutions for energy production. This study focused on diverse biomass materials, including sludge from WWTPs, forest biomass, swine waste, cork powder, and biochar. Chemical and physicochemical characterizations were performed to understand their energy potential, highlighting their elemental composition, proximate analysis, and calorific values. Results showed that different biomasses have varying energy content, with biochar and cork powder emerging as high-energy materials with net heating values of 32.56 MJ/kg and 25.73 MJ/kg, respectively. WWTP sludge also demonstrated considerable potential with net heating values of around 14.87 MJ/kg to 17.44 MJ/kg. The relationships between biomass compositions and their heating values were explored, indicating the significance of low nitrogen and sulphur content and favourable carbon, hydrogen, and moisture balances for energy production. Additionally, this study looked into the possibility of mixing different biomasses to optimize their use and overcome limitations like high ash and moisture contents. Mixtures, such as “75% Santo Emilião WWTP Sludge + 25% Biochar,” showed impressive net heating values of approximately 21.032 MJ/kg and demonstrated reduced emissions during combustion. The study’s findings contribute to renewable energy research, offering insights into efficient and sustainable energy production processes and emphasizing the environmental benefits of biomass energy sources with low nitrogen and sulphur content. Full article
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19 pages, 4939 KiB  
Article
Application of Wood and Vegetable Waste-Based Biochars in Sustainable Agriculture: Evaluation on Nitrate Leaching, Pesticide Fate, Soil Properties, and Brassica oleracea Growth
Environments 2024, 11(1), 13; https://doi.org/10.3390/environments11010013 - 06 Jan 2024
Viewed by 526
Abstract
Environmental pollution is caused by the unsustainable use of nitrogen (N) fertilizers and pesticides. Biochar (BC) is a carbon-based material applied to remove excess nutrients and pesticides from the environment. In pot experimental research, N fertilizer and pesticides alone and different biochar types [...] Read more.
Environmental pollution is caused by the unsustainable use of nitrogen (N) fertilizers and pesticides. Biochar (BC) is a carbon-based material applied to remove excess nutrients and pesticides from the environment. In pot experimental research, N fertilizer and pesticides alone and different biochar types were applied in the soil to evaluate cauliflower growth, soil quality, and leaching of agricultural contaminants. BC addition had increased nutrient availability based on feedstock origin. The surface structure results by SEM showed that the BC pore size was equal to 8.94 and 7.24 µm for mixed biochar and wood biochar, respectively. Nitrate concentrations in percolation water were 43.78 and 76.82 mg/L in mixed biochar and wood biochar, respectively. In soil treated with fertilizer and pesticides, NO3 was equal to 106.76 mg/L. Biochar’s binding with pesticides depends on its nature and structure. Adding wood biochar significantly reduced the leaching of fungicide compared to unamended soil, with a contraction of 327.86 and 3576 ng/L. Mixed biochar was more efficient for herbicide mitigation. FTIR was used to identify the functional groups on biochar-amended soil that play a role in the adsorption of agricultural compounds. Research shows that the BC application greatly affects the pesticide fate and N compounds of agricultural origin in soil. Full article
(This article belongs to the Special Issue Monitoring of Contaminated Water and Soil)
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15 pages, 3188 KiB  
Article
Effects of Exposure to Urban Atmospheric Particulate Matter Suspended in Seawater on the Mussel Mytilus galloprovincialis
Environments 2024, 11(1), 12; https://doi.org/10.3390/environments11010012 - 05 Jan 2024
Viewed by 656
Abstract
Atmospheric particulate matter (PM) contains numerous constituents, including organic molecules, inorganic ions, and metals, with some of them possessing hazardous properties. Although mainly associated with air pollution, PM can rapidly be transferred from air and land to aquatic ecosystems, and consequently poses a [...] Read more.
Atmospheric particulate matter (PM) contains numerous constituents, including organic molecules, inorganic ions, and metals, with some of them possessing hazardous properties. Although mainly associated with air pollution, PM can rapidly be transferred from air and land to aquatic ecosystems, and consequently poses a risk to marine biota. The aim of this work was to evaluate how urban atmospheric PM (a standard reference mixture of urban PM, known to contain various organic and inorganic contaminants), suspended in seawater, may cause toxicity in marine organisms. To this purpose, mussels (Mytilus galloprovincialis) were exposed to two concentrations of suspended PM: 5.7 and 11.4 mg/L. After 7, 14, and 21 days, the animals were collected and the gills and digestive gland were analysed for stress biomarkers (CAT, SOD, GPX, GST, MDA, and Ubi). In general, the results show that exposure to different concentrations of PM caused an increase in GST, UBI, and GPx activities compared to their respective controls. The average activities of GST (87.65 ± 30.23 nmol/min/mg of total protein) in the gills of the animals exposed to 11.4 mg/L of PM increased after 21 days of exposure, and the activity of GPx (8.04 ± 3.09 nmol/min/mg of total protein) in the gills increased after 14 days in the animals exposed to 5.7 mg/L of PM. MDA results also provided information on cellular damage, with the most pronounced effects being found in the gills of exposed mussels. This study confirms that mussels are useful as “early warning” indicators of environmental contamination and provides important information on the effects of PM on marine biota. Full article
(This article belongs to the Special Issue Advances in Urban Air Pollution)
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19 pages, 847 KiB  
Systematic Review
The Impact of Exposure to Hexavalent Chromium on the Incidence and Mortality of Oral and Gastrointestinal Cancers and Benign Diseases: A Systematic Review of Observational Studies, Reviews and Meta-Analyses
Environments 2024, 11(1), 11; https://doi.org/10.3390/environments11010011 - 04 Jan 2024
Viewed by 709
Abstract
Background: Limited evidence suggests a possible connection between natural or occupational exposure to chromium and an increased risk of gastrointestinal cancer. The main objective of this study is to investigate the literature regarding chromium exposure and gastrointestinal health issues (i.e., cancer). Methods: A [...] Read more.
Background: Limited evidence suggests a possible connection between natural or occupational exposure to chromium and an increased risk of gastrointestinal cancer. The main objective of this study is to investigate the literature regarding chromium exposure and gastrointestinal health issues (i.e., cancer). Methods: A systematic literature search was performed using PubMed, Google Scholar and ScienceDirect. Included observational studies were assessed for their risk of bias. Results: 16 observational studies and 7 reviews and meta-analyses met the inclusion criteria. Most of the studies investigated gastric and hepatocellular cancer, followed by colorectal, oral, esophageal and pancreatic cancer. There is a limited amount of evidence regarding non-malignant gastrointestinal diseases. Chromium exposure is suspected to increase gastric and colorectal cancer risks. We did not find any convincing indications for increases in oral, esophageal and hepatocellular cancer. Pancreatic, gallbladder and extrahepatic bile ducts carcinogenesis is likely not associated with chromium exposure. Conclusion: We found weak evidence that chromium exposure is associated with gastric and colorectal cancer. Our review also highlights the existing controversial evidence regarding oral, esophageal and hepatocellular cancer, as well as the gap in studies investigating small intestinal cancer and non-malignant gastrointestinal health issues. Full article
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22 pages, 2901 KiB  
Article
Assessment of the Impact of War on Concentrations of Pollutants and Heavy Metals and Their Seasonal Variations in Water and Sediments of the Tigris River in Mosul/Iraq
Environments 2024, 11(1), 10; https://doi.org/10.3390/environments11010010 - 03 Jan 2024
Viewed by 426
Abstract
The war-related contamination of water and sediment of the Tigris River within the urban area of Mosul leads to seasonally independent exceedances of the WHO limit values for Cd, Pb, Cr, and Ni in water and sediments. Furthermore, exceedances consistently occur for conductivity, [...] Read more.
The war-related contamination of water and sediment of the Tigris River within the urban area of Mosul leads to seasonally independent exceedances of the WHO limit values for Cd, Pb, Cr, and Ni in water and sediments. Furthermore, exceedances consistently occur for conductivity, PO43, and SO42, as well as sporadically for salinity and COD in water samples, and consistently for salinity in sediment samples, highlighting the direct impact of war (ammunition, ignition of sulfur fields), as well as indirect effects (destroyed wastewater infrastructure). Conflict-related emissions from the former conflict zone (S5–S7) are highlighted by the sudden increases in load from S4 to S5, although partially masked by the discharge of highly polluted water from the Khosr River (between S3 and S4). Due to the sorption of sediments and the presumed wind-borne discharge of highly polluted particles into the Tigris River, sediments at S10 on the southern edge of Mosul showed the highest pollutant loads. Significant statistical differences were observed through T-test analyses for E.C., TDS, salinity, COD, PO43, NO3, SO42, Cd, Pb, Zn, Cr, and Ni for water samples, as well as salinity, Cd, Pb, Zn, and Cr for the sediment samples for seasonal comparison. Since the percentage difference of water samples at S4–S7 is smaller than upstream and downstream, contaminant input is not limited to rainwater but also occurs via the year-round infiltration of highly polluted wastewater from the surrounding valleys or suburban areas, as well as presumably polluted groundwater or windblown particulate input. Full article
(This article belongs to the Special Issue Advanced Technologies of Water and Wastewater Treatment)
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14 pages, 6617 KiB  
Article
Determination of Ozone Concentration Levels in Urban Environments Using a Laser Spectroscopy System
Environments 2024, 11(1), 9; https://doi.org/10.3390/environments11010009 - 02 Jan 2024
Viewed by 403
Abstract
In urban areas, there has been a recent rise in ground-level ozone. Given its toxicity to both humans and the environment, the investigation of ozone pollution demands attention and should not be overlooked. Therefore, we conducted a study on ozone concentration in three [...] Read more.
In urban areas, there has been a recent rise in ground-level ozone. Given its toxicity to both humans and the environment, the investigation of ozone pollution demands attention and should not be overlooked. Therefore, we conducted a study on ozone concentration in three distinct locations within the city of Magurele, Romania. This investigation considered variations in both structure and location during the spring and summer seasons, specifically at a breathing level of 1.5 m above the ground. Our analysis aimed to explore the impact of different locations and meteorological variables on ozone levels. The three measurement points were strategically positioned in diverse settings: within the city, in a forest, and within an industrial area. For these measurements, we used a laser spectroscopy system to determine the system’s sensitivity and selectivity and the influence of humidity in the detection of ozone in ambient air, which is a mixture of trace gases and water vapor. During the March–August campaign, the mean values in the three measuring points were 24.45 ± 16.44 ppb, 11.96 ± 3.80 ppb, and 95.01 ± 37.11 ppb. The peak concentrations of ozone were observed during the summer season. A diurnal analysis revealed that the atmospheric ozone levels were higher in the latter part of the day compared to the earlier part. These measurements suggest that the atmospheric temperature plays a significant role in tropospheric ozone production. Additionally, meteorological variables such as wind speed and direction were found to influence the ozone concentration. Remarkably, despite substantial traffic, the ozone levels remained consistently low throughout the entire period within the forested area. This observation may suggest the remarkable ability of trees to mitigate pollution levels. Full article
(This article belongs to the Special Issue Air Pollution in Urban and Industrial Areas II)
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32 pages, 2087 KiB  
Systematic Review
Interdisciplinary Perspectives on Green Infrastructure: A Systematic Exploration of Definitions and Their Origins
Environments 2024, 11(1), 8; https://doi.org/10.3390/environments11010008 - 02 Jan 2024
Viewed by 535
Abstract
Green Infrastructure (GI) is rooted in ecology and cuts across multiple disciplines, including landscape architecture, environmental sciences, planning, policy, and engineering. Likewise, the definition of this concept also cuts across disciplines, which creates ambiguity around what GI is and what makes up GI [...] Read more.
Green Infrastructure (GI) is rooted in ecology and cuts across multiple disciplines, including landscape architecture, environmental sciences, planning, policy, and engineering. Likewise, the definition of this concept also cuts across disciplines, which creates ambiguity around what GI is and what makes up GI in practice—for example, mistaking bioswales for regular tree planters or green space within communities in which they are installed. We undertook a systematic literature review of 38 peer-reviewed articles for this study using the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) method to identify and synthesize the different disciplinary definitions of GI in the literature. This study also presents the types of GI systems mentioned in the peer-reviewed articles while identifying other benefits apart from the primary benefit of GI installation, which is stormwater management. The analysis revealed three clusters of GI definitions: (I) Interconnected natural areas and other open spaces, (II) Strategically planned natural and semi-natural areas, and (III) Decentralized systems and techniques. However, we got rid of the third cluster during the analysis because GI is known to be a decentralized system, and the definition region could not be tracked. These clusters represent a spectrum, one of which employs the structure of natural systems already in place to support human goals (bio-inclusivity). The other includes living systems as components within engineered solutions to achieve objectives (bio-integration). This review points to the need for an encompassing definition that cuts across disciplines with a consensus on the adoption and concise categorization of GI types and the multiple benefits they provide to humans and ecosystems. A consensus definition helps clear misconceptions and improve the understanding of GI, potentially improving receptivity towards these solutions within communities from a community member perspective. Full article
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14 pages, 1886 KiB  
Article
Composted Sewage Sludge as a Substrate for Commercial Seedlings of Peltophorum dubium (Spreng.) Taub.
Environments 2024, 11(1), 7; https://doi.org/10.3390/environments11010007 - 02 Jan 2024
Viewed by 470
Abstract
Sewage sludge in natura is rich in nutrients, water, and organic matter and is essential for plant development. However, sewage sludge is diluted with water when composted, which could hamper plant growth. Therefore, supplementation with chemical fertilization may be necessary. This study evaluated [...] Read more.
Sewage sludge in natura is rich in nutrients, water, and organic matter and is essential for plant development. However, sewage sludge is diluted with water when composted, which could hamper plant growth. Therefore, supplementation with chemical fertilization may be necessary. This study evaluated the performance of composted sewage sludge (CSS) in producing Peltophorum dubium (Spreng.) Taub. seedlings with and without chemical fertilization via fertigation. The experiment was completely randomized in a 3 × 4 factorial scheme, with four fertigation (Ca(NO3)2(H2O)x: 0.87; (NH4)(H2PO4): 0.21; KCl: 0.47; (NH4)2SO4: 0.11; CH₄N₂O: 0.54; MgSO4: 0.52; Fe (13%): 0.03; B(OH)3: 6.00; CuSO4: 0.60; ZnSO4: 1.40; MnSO4: 6.00; Na2MoO4: 0.16 g L−1) doses: zero, standard, duplicate, and quadruplicate. In addition, three substrates were used: commercial substrate as the control, sewage sludge composted with sugarcane bagasse (LBC), and sewage sludge composted with Eucalyptus bark (LCE). The development of the seedlings was measured through the following variables: height, stem diameter, shoot/root ratio, leaf dry mass, root dry mass, total dry mass, green color index, the Dickson Quality Index, and the accumulation of nutrients in plant tissue. The seedlings produced with LCE that were subjected to the standard dose (1×) and the quadruplicate dose (4×) had the statistically highest mean values for most variables. Nevertheless, supplementation with chemical fertilization was necessary. Composted sewage sludge with eucalyptus bark, at the standard dosage, can be used for the commercial production of P. dubium seedlings, thus preventing the dangerous disposal of waste and strongly decreasing associated environmental hazards. Full article
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14 pages, 4553 KiB  
Article
Sustainability Assessment of Highly Fluorescent Carbon Dots Derived from Eucalyptus Leaves
Environments 2024, 11(1), 6; https://doi.org/10.3390/environments11010006 - 01 Jan 2024
Viewed by 528
Abstract
Biomass-derived carbon dots (CDs) are gaining much interest in recent times, as they provide a sustainable option with abundant availability, a low cost and tunable luminescence. Herein, we report a simple green synthesis method to produce highly fluorescent CDs from Eucalyptus globulus leaves [...] Read more.
Biomass-derived carbon dots (CDs) are gaining much interest in recent times, as they provide a sustainable option with abundant availability, a low cost and tunable luminescence. Herein, we report a simple green synthesis method to produce highly fluorescent CDs from Eucalyptus globulus leaves using the one-pot hydrothermal approach. The fabricated CDs exhibit strong blue fluorescence with an excitation and emission maxima of 320 nm and 445 nm, respectively. The highest quantum yield (QY) obtained was 60.7%. With the reported optical properties and biocompatibility, CDs can be looked at as a promising candidate for potential biosensing applications. Moreover, we employed a life cycle assessment (LCA) cradle-to-gate approach to study the environmental impacts of the synthesis strategy used for the fabrication of CDs. The results point out that citric acid is the main hotspot in CD synthesis, regarding environmental impacts in most categories. This justifies the introduction of biomass, which reduces the amount of citric acid, thus leading to a more sustainable synthesis strategy for fabricating CDs. Full article
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16 pages, 1242 KiB  
Article
A Dynamic Multiple Reaction Monitoring Analytical Method for the Determination of Fungicide Residues in Drinking Water
Environments 2024, 11(1), 5; https://doi.org/10.3390/environments11010005 - 26 Dec 2023
Viewed by 525
Abstract
The extensive use of fungicides causes their continuous release into the environment through spraying, soil seepage, leaching, and runoff. It has been observed that their residues can be found in foods and a variety of environmental compartments, such as wastewater, lakes, rivers, sediments, [...] Read more.
The extensive use of fungicides causes their continuous release into the environment through spraying, soil seepage, leaching, and runoff. It has been observed that their residues can be found in foods and a variety of environmental compartments, such as wastewater, lakes, rivers, sediments, drinking water sources (groundwater and surface water), treated water, and drinking water. A sensitive GC-MS/MS, using dynamic multiple reaction monitoring, an analytical method was developed to determine 10 fungicides (azoxystrobin, boscalid, captan, cyproconazole, cyprodinil, hexaconazole, metalaxyl, myclobutanil, paclobutrazol, and prochloraz) in drinking water. A solid-phase extraction method for sample preparations and validations was performed according to SANTE 2019 guidelines. All fungicides demonstrated mild or medium matrix effects (ME) ranging from 40.1% to 11.2%. Their recoveries ranged between 60% and 110%. The limits of detection were equal to or higher than 0.01 μg/L. The method was employed on 18 drinking water samples collected from public taps in Northern Evros, Greece, distributed in six sampling sites. Azoxystrobin, boscalid, cyproconazole, cypronidil, metalaxyl, and paclobutrazol mean concentrations did not surpass the allowable limit of 0.1 μg/L set by EU in any sampling site. Hexaconazole mean concentrations were higher than 0.1 μg/L in one sampling site, while prochloraz mean concentration showed limit exceedances in all sampling sites. Captan was not detected in any sampling site, and myclobutanil mean concentrations demonstrated exceedances of the permissible limit in four sampling sites. The presence of fungicide residues in the studied area is mainly due to the occasional point-sources pollution and preferential flow. Additionally, through the use of water, the risk of pesticides to human health was assessed for two different age groups. The sum of the hazard quotient values in each of the studied drinking water was less than unity. Consequently, the acute risk assessment procedure regards the examined drinking water as safe. Nevertheless, as prochloraz carcinogenic risk values were higher than the safe limit suggested by USEPA for both age groups, the existence of prochloraz residues raises concerns about chronic toxicity. Full article
(This article belongs to the Special Issue Environmental Risk Assessment of Aquatic Ecosystem)
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19 pages, 1015 KiB  
Review
A Scoping Review of the Effects of Ambient Air Quality on Cognitive Frailty
Environments 2024, 11(1), 4; https://doi.org/10.3390/environments11010004 (registering DOI) - 20 Dec 2023
Viewed by 760
Abstract
Environmental and public health research has given considerable attention to the impact of air quality on brain health, with systematic reviews being widespread. No literature review has been conducted for cognitive frailty—a multidimensional syndrome combining physical frailty and cognitive impairment and their apparent [...] Read more.
Environmental and public health research has given considerable attention to the impact of air quality on brain health, with systematic reviews being widespread. No literature review has been conducted for cognitive frailty—a multidimensional syndrome combining physical frailty and cognitive impairment and their apparent co-dependence, linked to increased vulnerability and adverse health outcomes, including dementia. Instead, cognitive decline and frailty are implicitly explored through research on air quality and comorbid cognitive and physical decline in elderly populations. A scoping review was conducted to explore the need for a systematic review. Combining the Arksey and O’Malley, and PRISMA-ScR checklist, a scoping review of SCOPUS using ‘cogniti*’ + ‘resilience’ + ‘air quality’ or ‘cogniti*’ + ‘ageing’ + ‘air quality’ resulted in n = 2503 articles, screened and reduced using inclusion and exclusion criteria, to n = 16 articles. Air quality appears to be a critical risk factor for cognitive decline, even at air quality levels below WHO targets. Moderate long-term ambient air pollution appears linked to increased risk of cognitive frailty, suggesting earlier and more active interventions to protect older people. There are varied effects on cognition across the life course, with both emotional and functional impacts. Effects may be more detrimental to elderly people with existing conditions, including economic and health inequalities. Generalisation of results is limited due to the absence of a dose–response, variations in methods, controlling for comorbid effects, and variance across studies. No literature review has been performed for cognitive frailty, largely due to the fact that it is not presently treated as an explicit outcome. The findings support the need for more research and a more extensive summary of the literature but suggest that there is worsening cognitive function over the life course as a result of increased PM2.5 concentrations. Furthermore, air quality appears to be a critical risk factor even at levels below World Health Organisation targets. Full article
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15 pages, 7674 KiB  
Article
A Comparative Study on the Removal of Microcystis and Cylindrospermopsis Blooms in Two Lakes by Flocculation–Filtration Treatment
Environments 2024, 11(1), 3; https://doi.org/10.3390/environments11010003 - 20 Dec 2023
Viewed by 417
Abstract
Dianchi Lake and Yilong Lake, two prominent plateau lakes in Yunnan Province, China, have suffered from Microcystis and Cylindrospermopsis blooms for decades. While cyanobacteria harvest boats utilizing cationic polyacrylamide (CPAM) flocculation and screen filtration have been proven effective for harvesting Microcystis biomass in [...] Read more.
Dianchi Lake and Yilong Lake, two prominent plateau lakes in Yunnan Province, China, have suffered from Microcystis and Cylindrospermopsis blooms for decades. While cyanobacteria harvest boats utilizing cationic polyacrylamide (CPAM) flocculation and screen filtration have been proven effective for harvesting Microcystis biomass in Dianchi Lake, they struggle against Cylindrospermopsis blooms in Yilong Lake. This study systematically compared the removal of Microcystis and Cylindrospermopsis blooms using flocculation–filtration treatment, aiming to identify key factors influencing flocculation and propose enhancements to improve treatment efficiency for Cylindrospermopsis blooms. The reduction of turbidity, OD680, biovolume and phytoplankton density all revealed significantly better treatment efficiency for Microcystis blooms compared to Cylindrospermopsis blooms. In Dianchi Lake, 1 mg/L CPAM achieved a 95% turbidity reduction, while in Yilong Lake, even with 4.0 mg/L CPAM, the removal efficiency remained below 90%. Post-treatment, Dianchi Lake’s water quality showed substantial improvements, including over 50% reductions in total nitrogen, total phosphorus, permanganate index, and chemical oxygen demand. Conversely, nutrient level reductions were limited in Yilong Lake’s treated water. The average molecular weight of dissolved organic matters (DOM) in Yilong Lake was notably smaller than in Dianchi Lake. The treatment selectively removed high molecular weight, microbial-sourced, and protein-like DOM components, leading to a decrease in average molecular weight and an increase in humification index (HIX) in both lakes. Excessive humic matters in the water of Yilong Lake was found to hamper algae flocculation significantly. Introducing additional acidic polysaccharides or oxidants emerged as potential strategies to enhance Yilong Lake’s treatment efficiency. Full article
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15 pages, 12661 KiB  
Article
Effect of Bark Biochars on Properties of Steam-Activated Carbons
Environments 2024, 11(1), 2; https://doi.org/10.3390/environments11010002 - 20 Dec 2023
Viewed by 565
Abstract
Bark is a heterogeneous solid material comprising mainly of phloem and cork fractions. These fractions differ in chemical composition and anatomical structure, and value-added activated carbons produced from these fractions have different surface properties. Low-temperature pyrolysis was shown to be a promising method [...] Read more.
Bark is a heterogeneous solid material comprising mainly of phloem and cork fractions. These fractions differ in chemical composition and anatomical structure, and value-added activated carbons produced from these fractions have different surface properties. Low-temperature pyrolysis was shown to be a promising method for producing activated carbon precursors from bark fractions at higher yields than conventional slow pyrolysis. Here, we produced mesoporous activated carbons (ACs) from cork and phloem fractions of Quercus cerris bark by low-temperature pyrolysis followed by steam activation at 900 °C. The results showed steam-activation of biochars from Q. cerris bark fractions yielded ACs with acceptable surface properties. The ACs contained 9.9% and 23.3% ash content, and specific surface areas of 201 m2 g−1 and 512 m2 g−1 for cork and phloem fractions, respectively. Calcium was the principal inorganic component of ACs, followed by potassium, silicon, and iron. Surface functional groups of bark fractions and biochars were lost during steam activation, as evidenced by FT-IR spectroscopy. The burnout temperatures of cork and phloem ACs were 726 °C and 736 °C, respectively. The ACs showed a high methylene blue and methyl orange adsorption capacity, with the removal of 80% and 90% of methylene blue and 58% and 68% of methyl orange after 48 h for cork and phloem ACs, respectively. Full article
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15 pages, 1183 KiB  
Article
Adult Chironomid (Chironomidae: Diptera) Positive Phototactic Behaviour—A Cue for Adult Population Management and Impact on Insect Biodiversity at Lake Trasimeno, Central Italy
Environments 2024, 11(1), 1; https://doi.org/10.3390/environments11010001 - 19 Dec 2023
Cited by 1 | Viewed by 518
Abstract
The positive phototaxis showed by adults of some pestiferous chironomid species, annoying to waterfront residents and businesses, was investigated at Lake Trasimeno (Italy) to develop a strategy against their massive swarms. Two experimental devices (ChiroTraps), located at Passignano sul Trasimeno (PA) and at [...] Read more.
The positive phototaxis showed by adults of some pestiferous chironomid species, annoying to waterfront residents and businesses, was investigated at Lake Trasimeno (Italy) to develop a strategy against their massive swarms. Two experimental devices (ChiroTraps), located at Passignano sul Trasimeno (PA) and at Sant’Arcangelo (SA), were employed in 2019 and 2020. The total biomass attracted by the traps amounted to 6498.78 g at PA and to 8597.05 g at SA. Chironomids biomass constituted 99.66% and 96.59% of the biomass in these sites, respectively. Only a few specimens of other fauna except chironomids were found at PA. In contrast, the values at SA were considerable, being 91- and 35-fold (number of taxa and weight, respectively) higher than in PA. These results demonstrated that exploiting the light attraction behaviour of adult chironomids is an efficient method for managing their pestiferous populations, thereby reducing the necessity of using insecticides. By comparing the biodiversity in the two sites, it was evident that the differences were linked primarily to the environmental conditions. Finally, it is suggested that light trapping systems should be located in urban centres or floated on the lake surface to maximise the efficiency of trapping chironomids and minimising the impact on biodiversity. Full article
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