Search Results (5,132)

Heavy metal pollution poses a significant threat to aquatic ecosystems and drinking water sources, necessitating comprehensive environmental assessments. This study investigated the spatial distribution, potential ecological risks, and sources of heavy metals in the surface sediments of Wanfeng Lake to inform effective pollution management strategies. Twelve sediment samples were collected and analyzed for eight heavy metals (Hg, As, Cu, Pb, Cd, Cr, Ni, Zn) using inductively coupled plasma mass spectrometry. The geo-accumulation index (I_geo) and potential ecological risk index (RI) were applied to assess contamination levels and ecological risks. Cluster analysis and Kriging interpolation were used to identify potential pollution sources and spatial patterns. Results revealed that heavy metal concentrations decreased in the order Zn > Pb > Cu > Cr > Ni > As > Cd > Hg, with Hg concentrations exceeding the national average for Chinese lake sediments. Ecological risk assessments identified Hg (0.06 μg/g) and Cd (0.10 μg/g) as the priority pollutants. The Hg posed a moderate ecological risk, particularly in upstream areas, while Cd pollution was concentrated downstream. Atmospheric deposition was identified as the primary source of Hg, whereas agricultural activities were determined to be the main driver of Cd contamination. These findings provide a scientific basis for developing targeted pollution control measures in Wanfeng Lake. Full article

This study highlights the significant environmental and health risks associated with heavy metal contamination (As, Cd, Cr, and Pb) in Oreochromis niloticus (Nile tilapia) from two locations: the Khon Kaen municipal landfill (study site) and the Thapra commercial fish farm (reference site). It also evaluates potential human health risks and investigates genotoxicity and oxidative stress markers, including malondialdehyde, hydrogen peroxide (H₂O₂), catalase (CAT), and superoxide dismutase (SOD) in fish. Heavy metal concentrations were analyzed using inductively coupled plasma optical emission spectrometry. To determine genetic differentiation, inter-simple sequence repeats with dendrogram construction and genomic template stability (%GTS) were applied. The results showed that the average concentrations of As, Cd, Cr, and Pb in water samples were 0.0848, 0.536, 1.23, and 0.73 mg/L, respectively. These values exceeded safety limits, and the average Cd in sediment (1.162 mg/kg) was above regulatory thresholds. In fish muscle, the average metal concentrations (mg/kg) followed the order Cr (1.83) > Pb (0.69) > Cd (0.096) > As (0.0758), with Pb exceeding food quality standards. The bioaccumulation factor ranked as Cr > Pb > As > Cd. Health risk assessments, including health risk index and carcinogenic risk, suggested Pb contamination poses significant health risks through fish consumption. From dendrogram results, the %GTS of O. niloticus from the landfill and reference sites were 46.34 to 71.67% and 87.34 to 96.00%, respectively. This suggests that fish from the landfill site exhibited greater genetic diversity compared to those from the reference site. Specific oxidative stress markers revealed higher levels of H₂O₂ and significantly lower activities of CAT and SOD in landfill O. niloticus than in the reference site. These results emphasize the urgent need for environmental monitoring, stricter pollution controls, and improved waste management strategies to protect aquatic ecosystems and human health. Full article

Biofouling, the undesirable deposition of microorganisms on surfaces, is ubiquitous in aqueous systems. This is no different for systems running with water-miscible metalworking fluids (MWFs), which additionally contain many organic chemicals that create favorable conditions for growth and metabolism. Biofilm formation is thus inevitable, as there is no shortage of wetted surfaces in metalworking systems. MWF manufacturers tried in vain to offer resistance by using biocides and biostatic compounds as ingredients in concentrates and as tank-side additives. We report here that such elements, alone or as components of MWFs, did not prevent biofilm formation and had negligible effects on pre-established laboratory biofilms. Moreover, biofilms in metalworking systems are interwoven with residues, sediments, and metal swarfs generated during machining. Again, co-incubation of such “real” biofilms with MWFs had no significant effect on population size—but on population composition! The implications of this finding are unclear but could provide a starting point for the treatment of biofouling, as biofilm population structure might be of importance. Finally, we show that bacteria gain function in biofilms and that they were able to degrade a toxic amine in MWFs, which the same bacteria were unable to do in planktonic form. Full article

The use of mineral waste for the production of lightweight artificial aggregate is an important element of activities for sustainable development in construction and the implementation of the objectives of the circular economy. The article presents the physical, mechanical, and ecological properties of an innovative artificial aggregate produced from bottom sediments, concrete dust, and municipal solid waste incineration fly ash. The obtained research results confirm that the developed material achieves technological properties comparable to artificial aggregates available on the market, both commercial and those derived from recycling. However, the increased leachability of chlorides and sulphates remains a significant challenge, which may limit the scope of its applications. Despite this, the material shows the potential for use, among others, in the production of lightweight concrete. The analyses carried out have shown that the thermal hardening processes (200–400 °C) and autoclaving do not guarantee full immobilization of harmful substances contained in the raw materials for the production of this type of aggregate. Full article

Phosphorus plays a key role in water eutrophication. The release of endogenous phosphorus from sediments maintains eutrophication in Dianchi Lake. This study aimed to summarize and analyze the research trends, occurrence characteristics, adsorption and release characteristics, influencing factors, and prospects of internal phosphorus pollution control in Dianchi Lake based on a literature search and data integration. The results revealed that sediment phosphorus in Dianchi Lake has been widely studied. From previous studies, the total phosphorus (TP) content and various forms of phosphorus in the Dianchi Lake sediments have decreased since 2010. The TP contents measured in Dianchi Lake in previous research were considerably different owing to the influence of sampling depth and dredging projects. The TP content in the sediments of Dianchi Lake was higher but its release risk was lower than those in other lakes in China. The risk of release was higher in Caohai and North Waihai than that in Central Waihai and South Waihai. In addition to environmental factors at the sediment–water interface, sediment characteristics, and ecosystem degradation are important factors that affect phosphorus migration and transformation. Over the past 30 years, sediment dredging has been the primary measure for reducing the internal pollution load in Dianchi Lake. However, more accurate sediment dredging and systematic vegetation–algae–sediment co-management measures are needed for water ecosystem restoration in Dianchi Lake. This study provides new insights into the study of internal phosphorus pollution. Full article

The artisanal production of paints using inorganic pigments from the Cusco Valley is considered a sustainable alternative to the use of synthetic industrial paints. This approach not only helps reduce the environmental footprint associated with the use of volatile organic compounds (VOCs) but also utilizes local materials. The present study evaluates the physical and mechanical properties of paints obtained from natural pigments through standardized tests based on the American ASTM standards, focusing on adhesion (ASTM D-3359), drying time (ASTM D-1640), surface hardness (ASTM D-3363), and the performance of the paints when exposed to the environmental factors of Cusco (under real conditions). In this regard, the pigments were extracted from traditional quarries and processed through the sedimentation method (MS) and ball milling (MG). The produced paints were formulated with the addition of polyvinyl acetate (PVA) as a binder and water as a solvent and were applied to standardized panels. The results show that all samples meet the requirements of the technical parameters, demonstrating good adhesion, appropriate drying times, and acceptable hardness for architectural coatings, Chromatic variations (ΔE*) were recorded depending on the processing method and the level of environmental exposure, with paints containing ground pigments (MG) being more resistant to fading. This study concludes that these artisanal formulations represent a technically viable and culturally relevant alternative to industrial coatings, especially in contexts of heritage restoration or sustainable architecture. Full article

Over the past two decades, extensive coastal development in China has led to numerous small-scale enclosed coastal water bodies. Due to complex shoreline geometries, these areas suffer from disturbed hydrodynamic conditions, weak water exchange, which quickly leads to sediment accumulation, and difficulty maintaining ecological water levels, posing serious environmental threats. Enhancing seawater exchange capacity and achieving coordinated optimization of exchange efficiency and ecological water level are critical prerequisites for the environmental restoration of eutrophic enclosed coastal areas. This study takes the Ligao Block in Tianjin as a case study and proposes a real-time sluice gate regulation scheme. By incorporating hydrodynamic conditions, engineering layout, and present characteristics of the benthic substrate environment, the number, width, location, and operation modes of sluice gates are optimized to maximize water exchange efficiency while maintaining natural flow patterns. The result of the numerical simulation of hydrodynamic exchange and intelligent optimization analysis reveals that the optimal sluice gate operation strategy should be tailored to regional tidal flow characteristics and substrate conditions. Through intelligent scheduling of exchange sluice gates, systematic gate parameter optimization, and active control of gate opening, this approach achieves intelligent seawater exchange, optimized flow dynamics, active exchange, and sustained ecological water levels in enclosed coastal water bodies. Full article

Inland saline wetlands in the Ebro Basin (Spain) are protected by international regulations but are also threatened by the expansion of animal farms. We studied the input–output budgets of N from animal farms in four catchments of wetlands in the central Ebro Basin designated as Nitrate Vulnerable Zones. We used the N produced in animal farms as inputs and the N extracted by the crops on which manures and slurries are applied as outputs in each catchment. The balances considered the regulations concerning the slope of land where animal excreta may be applied and the doses of application. At a detailed scale, we applied the Water Erosion Prediction Program (WEPP) to the Farnaca catchment to assess the runoff and nutrients arriving to its wetland. While the Bujaraloz-Sástago basin showed a high excess of N load, in the Gallocanta basin, N extraction by crops was significantly higher than the N produced by the animal farms. Despite this lack of surplus of N from animal excreta, the groundwaters in the Gallocanta catchment are polluted by nitrates. The emphasis on N from animal farms in plans to prevent water pollution is missing the role of mineral fertilizers as the sources of pollution in basins with small N loads from animal farms. Agricultural plots in the Farnaca catchment produce significant amounts of sediments and nutrients that eventually pollute the wetland. Modelling approaches at detailed scales are required to assess the flows of materials to individual wetlands. Full article

With the increasing global population and migration toward coastal regions, and the rising demand for coastal urbanization, including the development of living spaces, ports, and tourism infrastructure, the need for coastal defense structures (CDSs) is also increasing. Traditional CDSs, such as breakwaters, typically composed of hard units designed to block and divert wave and current energy, often fail to support diverse and abundant marine communities because of their impact on current and sediment transport, the introduction of invasive species, and the loss of natural habitats. Marine ecoengineering aims at increasing CDS ecological services and the development of marine organisms on them. In this study, carried out in a coral reef environment, we examined the relationship between coral colony protection levels and three factors related to their development, namely, coral fragment survival rate, larval settlement, and water motion (flow rate), across three distinct niches: Exposed, Semi-sheltered, and Sheltered. Coral survivability was assessed through fragment planting, while recruitment was monitored using ceramic settlement tiles. Water motion was measured in all defined niches using plaster of Paris Clod-Cards. Additionally, concrete barrier structures were placed in Exposed niches to test whether artificially added protective elements could enhance coral fragment survival. No differences were found in coral settlement between the niches. Flow rate patterns remained similar in Exposed and Sheltered niches due to vortex formation in the Sheltered zones. Survival analysis revealed variability between niches, with the addition of artificial shelter barriers leading to the highest coral fragment survival on the breakwater. This study contributes to the development of ways to enhance coral development with the goal of transforming artificial barriers into functional artificial reefs. Full article

The natural flow of sediment in the Ebro River has been altered by a variety of factors that have impacted the geomorphic and ecological balance of the delta. Ongoing restoration efforts in the delta would benefit if the flow of sediment in the river could be increased. Understanding the dynamics of sediment flow in the Ebro River is an important component in the design of effective management strategies for the Ebro Delta. This study estimates the sediment transport potential of the Ebro River under current and future conditions through numerical simulation. Historical data from the late 19th century indicate that the river once transported up to 28.1 million tons of sediment per year. However, due to water abstractions and flow regulations, the current sediment transport capacity is limited to 9 million tons annually, a reduction of 67%. Future projections suggest further decreases in flow and sediment transport potential, with reductions of up to 30% by 2060 and 50% by 2100, depending on climate conditions and water management practices. The findings underscore the need for integrated management strategies to mitigate the impacts of reduced sediment flow, emphasizing the importance of restoring sediment transport as a crucial component of the delta restoration efforts. Full article

Methane hydrate is a crystalline compound in which methane is trapped within a water lattice under high-pressure, low-temperature conditions. Its presence in oceanic and permafrost sediments makes it a promising alternative energy source, but also a potential contributor to climate change. Accurate in situ detection remains a major challenge due to hydrate’s dispersed occurrence and the limitations of conventional geophysical methods. This study investigates the feasibility of using the associated alpha particle (AAP) technique for the direct detection of methane hydrate. A series of laboratory measurements was conducted on sand-based samples with varying levels of methane hydrate simulant. Using a 14 MeV neutron generator and a LaBr₃ gamma detector, the 4.44 MeV carbon peak was monitored and calibrated against volumetric hydrate saturation. The minimum detection limit (MDL) was experimentally determined to be $(67\pm 25)\%$. Although the result is subject to high uncertainty, it provides a preliminary benchmark for evaluating the method’s sensitivity and highlights the potential of AAP-based gamma spectroscopy for in situ detection, especially when supported by higher neutron flux in future applications. Full article

The bacterial community in water from the Houston-toad captive assurance colony held at the Houston Zoo, TX, was used for comparison to the native pond bacterial composition by Ilumina-based 16S rRNA V3 amplicon sequencing. We analyzed composite sediment–water samples from native breeding ponds before and after the release of eggstrands, focusing on opportunistic pathogens of the genus Mycobacterium within the phylum Actinobacteria. Proximal native breeding ponds without headstarting were analyzed for comparison. Tank-water samples from holding facilities (NACQ, Rm1, Rm3, Rm4) showed similar bacterial profiles, with sequences identifying Proteobacteria (57.8 ± 6.2% of all reads), Bacteriodetes (28.1 ± 8.9% of all reads), and Firmicutes (4.1 ± 2.0% of all reads) generally accounting for more than 90% of all reads. Actinobacteria were identified in low abundance, accounting for 1.4 ± 1.1% of all reads, with Nocardiaceae being the most prominent group (54 to 75% of reads), followed by Microbacteriaceae (6 to 12%) and Mycobacteriaceae (1 to 3%). In the pond samples, Proteobacteria remained the most prominent phylum, comprising about 30% of all reads, though other phyla such as Acidobacteria, Actinobacteria, Bacteriodetes, Chloroflexi, Cyanobacteria, Firmicutes, Planctomycetes, Verrucomicrobia, and others were also well represented, ranging from 1% to 15%, with individual phyla peaking at specific sampling times. The prevalence of Actinobacteria sequences varied widely among ponds (<1 to 11% of all reads) and over time (10% and 1%). Most mycobacteria sequences retrieved from tank water were not detected in pond water. Thus, the potential introduction of opportunistic mycobacteria pathogens with tank water from holding facilities and eggstrands via headstarting does not seem to lead to the establishment of these bacteria in natal ponds. Full article

The blue crab Callinectes sapidus Rathbun, 1896 is native to the western coast of the Atlantic Ocean. Although its arrival to the Mediterranean was probably due to ballast water, this species has several characteristics that have enabled it to successfully invade countless localities in the Mediterranean and the Black Sea. Little is known about its feeding habits and ecosystem impacts in the Mediterranean basin. This study aimed to provide information on the natural diet of C. sapidus by comparing the stomach contents of specimens caught in different seasons and habitats of the SE Iberian Peninsula (hypersaline waters in Mar Menor Lagoon and brackish waters in Guardamar Bay). This study also tested whether gender influences prey selection and if ovigerous females exhibit limited feeding activity. Regarding the frequency of occurrence, the results indicated that in Mar Menor Lagoon the most frequently consumed prey were Crustacea (60%), followed by fish (57%) and Mollusca (29%), whilst in Guardamar Bay, Mollusca (40%), sediment (32%), algae (24%) and Crustacea (24%) were dominant. It has been determined that this species predates heavily on Mediterranean shrimp Penaeus kerathurus, an economically important shrimp species in the lagoon area. Analysis using a generalised linear model indicated that sex, season and size class were factors that significantly influenced the stomach content weight. Furthermore, non-ovigerous females had significantly fuller stomachs than ovigerous individuals. Since the population of Callinectes sapidus tends to increase in the Mediterranean basin, monitoring of its feeding ecology is recommended to determine its impact on the ecosystem. Full article

Miscanthus is considered a promising candidate for the cultivation of marginal land. This land poses unique challenges, and experiments have shown that the “establishment phase” is of paramount importance to the long-term yield performance of miscanthus. This experiment analyzes novel miscanthus hybrids and how their establishment on marginal land can be improved through agronomic interventions. Experiments took place at two sites in Germany: at Ihinger Hof, with a very shallow soil profile and high stone content, and at Reichwalde, where the soil was repurposed river sediment with low organic matter, high stone content, and a compacted lower horizon. These marginal conditions functioned as test cases for the improvement of miscanthus establishment agronomy. Four hybrids (Miscanthus x giganteus, Gnt10, Gnt43, and Syn55) and agronomic treatments such as plastic mulch film, miscanthus mulch, inoculation with mycorrhizal fungi, and fertilization were tested in two years at both sites in 2021 and 2022. Specific weather conditions and the timing of planting were strong determinants of establishment success and no single treatment combination was found that consistently increased the establishment success. Plastic mulch films were found to hinder rather than help establishment in both these locations. Chipped miscanthus mulch caused nitrogen immobilization and stunted plant growth. At Ihinger Hof the novel seed-based miscanthus hybrid Gnt43 produced twice the biomass of other hybrids (7 t ha⁻¹) in the first growing season. Gnt10 yielded well in 2021 and showed impressive tolerance to water stress in the summer of 2022. No treatment combination was found that consistently increased the establishment success of miscanthus hybrids across sites and years. Novel genotypes consistently outperformed the standard commercial miscanthus hybrid Miscanthus x giganteus. Gnt10 may be a promising candidate for the cultivation of water-stress-prone marginal lands, due to its isohydric behavior and high yield potential. Full article

Soil particle size distribution is a critical parameter in geotechnical and hydraulic engineering, particularly in applications such as dam seepage monitoring, building foundation assessments, and sediment transport. This study presents a novel algorithm for estimating soil particle sizes by analyzing their falling velocities in water, combining optical flow computation with chaotic motion analysis. To address the limitations of the classical Horn and Schunck method, particularly its sensitivity to large displacements and brightness variations, we introduced a coarse-to-fine warping strategy, an image decomposition step to separate dominant structures from fine textures, and the Charbonnier penalty function. The improved model achieved competitive accuracy compared to advanced optical flow algorithms. To manage turbulence and motion noise during particle settling, we incorporated a global flow analysis framework using streaklines, streak flow, and potential functions. This enabled the segmentation of laminar, turbulent, and rebound flow regions without requiring individual particle tracking. Soil particle sizes were then back-calculated from laminar flow velocities using Stokes’ Law. Experimental results confirmed the method’s accuracy for particle sizes ranging from 20 mm to 0.7 mm, significantly extending the measurable range of Sedimaging systems. The proposed approach shows strong potential for integration into dam-related particle monitoring applications and building-related monitoring systems requiring fine-resolution analysis. Full article