Search Results (8,266)

The decline in the injectivity of injection wells is a serious problem in geothermal systems. In this article, we analyse the mechanisms responsible for the reduction in permeability in Lower Jurassic sandstones during the injection of cooled formation brine. Flow experiments were conducted on rock cores using three types of brines with varying degrees of contamination. The studies included microscopic analysis, scanning electron microscopy (SEM) and mercury intrusion capillary pressure (MICP) before and after the experiments. The results showed that the main factor in the decrease in permeability is the formation of a filter cake from secondary iron minerals on the front surface of the core. Filter cake formation was observed in all samples, with ferrous sediment penetrating to a maximum depth of 1.5 cm from the core front. In addition, the mobilisation of clay particles was observed, which accumulate in pore constrictions, causing additional flow restriction. Mercury porosimetry revealed significant increases in hysteresis values in the front zone (from 16.5 to 42%), indicating complex pore connectivity changes without substantial porosity reduction. The rate of injectivity decline correlates strongly with the fluid flow velocity. The results of the study provide a scientific basis for optimising reinjection processes in geothermal systems and developing strategies to prevent formation damage. Full article

The Yamuna River, among India’s most polluted waterways, is burdened by industrial, agricultural, and domestic discharges containing complex organic and inorganic contaminants. This study introduces a novel, integrated approach combining comprehensive pollutant profiling by liquid chromatography–mass spectrometry (LC-MS) with bioremediation using laboratory-validated native algal consortia. Water samples from a severely polluted Delhi stretch revealed alarming levels of heavy metals (e.g., lead: 47.33 mg/L) and over 550 organic pollutants, including polychlorinated biphenyls, dioxins, carcinogens, and neurotoxins. Two consortia, each assembled from indigenous algal strains, were evaluated under controlled conditions against both pollutant-rich water and non-polluted controls. Consortium 1 (Scenedesmus, Chlorococcum, Oocystis) outperformed Consortium 2 (Chlorella, Klebsormidium, Monoraphidium), achieving up to 87.07% reduction in lead and >95% removal of nitrate and phosphate, alongside substantial decreases in chemical and biological oxygen demand. By integrating high-resolution chemical analytics with native microbial remediation, this work provides the first demonstration of simultaneous removal of diverse pollutant classes in Yamuna water. The findings establish native algal consortia as cost-effective, sustainable bioremediation tools and underscore LC-MS as a critical method for holistic aquatic pollution assessment. Full article

Asbestos tailings represent a historical liability in many countries. Canada aims at transforming this industrial legacy into an opportunity to both mitigate the environmental footprint and recover critical (such as magnesium, nickel, chromium, and cobalt) and strategic metals, which represent significant economic development potential. This study aimed to investigate the recovery of critical and strategic metals (CSMs) from asbestos tailings using hydrochloric (HCl) acid leaching, with acid concentration (2–12 mol/L), leaching temperature (20–90 °C), and solid–liquid ratio (10–40%) as key process parameters. The tailing samples studied is composed mostly of chrysotile and lizardite. It contains about 40% magnesium (as its oxide MgO) and nickel and chromium showing contents 52 and 60 times higher than their respective average crustal abundances (Clarke values). Iron content is 8.7% (expressed as its ferric oxide Fe₂O₃). To optimize key factors influencing the leaching process, a statistical experimental design was employed. The designed leaching experiments were subsequently performed, and results were used to define leaching conditions aiming at maximizing Mg and Ni recoveries while minimizing iron contamination using response surface methodology (RSM) based on the central composite design (CCD). A quadratic polynomial model was developed to describe the relationship between the process parameters and metal recoveries. Among the tested effects of acid concentration, temperature, and pulp density on magnesium recovery, the modeling indicated that both hydrochloric acid concentration and leaching temperature significantly enhanced metal recovery, whereas increasing pulp density had a negative effect at low temperature. The empirical mathematical model derived from the experimental data, accounting for the uncertainties on chemical data, indicated that high magnesium recovery was achieved at 90 °C, with 10–12 N hydrochloric acid and a solid-to-liquid ratio of 33.6–40%. These findings reveal the potential for the recovery of critical and strategic metals, both in terms of efficiency and economic viability. Full article

Lead and cadmium are prevalent heavy metal toxins that contaminate the natural environment through animal husbandry and agricultural and industrial activities. Exposing dairy cows to these pollutants can have detrimental effects on milk production and quality, leading to health problems and decreasing the animals’ production performance. Therefore, investigating the distribution of lead and cadmium content and assessing the pollution levels at dairy farms are of significant theoretical and practical significance. This study determined the spatial distribution and clustering of lead and cadmium by sampling soil and feces from dairy farms in Jiangsu, China. The data obtained, in conjunction with soil data from Jiangsu Province, were used to evaluate the extent of lead and cadmium pollution at these farms. The results indicate that lead pollution levels are relatively low, whereas cadmium pollution is moderate in multiple regions. Ultimately, this study contributes to the assessment of the risks associated with lead and cadmium in dairy farming production and supports the establishment of a sustainable animal husbandry system, serving as an effective reference for subsequent ecological health farming, disease prevention, and management. Full article

The transmission of Escherichia coli through contaminated fruits and vegetables poses serious public health risks and has led to several national outbreaks in the USA. To enhance food safety, rapid and reliable detection of E. coli on produce is essential. This study evaluated the performance of the CSI-D+ system combined with deep learning for detecting varying concentrations of E. coli on citrus and spinach leaves. Eight levels of E. coli contamination, ranging from 0 to 10⁸ colony-forming units (CFU)/mL, were inoculated onto the leaf surfaces. For each concentration level, 10 droplets were applied to 8 citrus and 12 spinach leaf samples (2 cm in diameter), and fluorescence images were captured. The images were then subdivided into quadrants, and several post-processing operations were applied to generate the final dataset, ensuring that each sample contained at least 2–3 droplets. Using this dataset, multiple deep learning (DL) models, including EfficientNetB7, ConvNeXtBase, and five YOLO11 variants (n, s, m, l, x), were trained to classify E. coli concentration levels. Additionally, Eigen-CAM heatmaps were used to visualize the spatial responses of the models to bacterial presence. All YOLO11 models outperformed EfficientNetB7 and ConvNeXtBase. In particular, YOLO11s-cls was identified as the best-performing model, achieving average validation accuracies of 88.43% (citrus) and 92.03% (spinach), and average test accuracies of 85.93% (citrus) and 92.00% (spinach) at a 0.5 confidence threshold. This model demonstrated an inference speed of 0.011 s per image with a size of 11 MB. These findings indicate that fluorescence-based imaging combined with deep learning for rapid E. coli detection could support timely interventions to prevent contaminated produce from reaching consumers. Full article

Waste dumpsites in developing countries are primary pollution sources impacting nearby ecosystems. This study assessed seasonal changes in soils surrounding the Hulene-B landfill (Maputo, Mozambique) and evaluated the potential for surface water contamination by leachates. A total of 71 samples were collected during the rainy and dry periods and analyzed for pH, electrical conductivity (EC), organic matter (OM), and color. The contamination potential (Pbci) was determined considering the landfill’s characteristics and local hydrological context. During the dry season, soils exhibited higher EC and OM, indicating greater retention of potentially toxic elements (PTEs) and a strong tendency for accumulation. In the rainy season, leaching processes prevailed, leading to reduced EC and OM but increased potential for contaminant mobility. The Pbci values were consistently high across both periods, confirming elevated contamination risk. Overall, the Hulene-B landfill exerts a marked influence on surrounding soils and nearby surface waters, underscoring the urgent need for structural measures to control leachate release and ash dispersion. Full article

Stainless steel forms a native film of mixed metal oxides, and organic impurities are likely to adsorb on the surface upon exposure to ambient conditions. For many applications, oxides and impurities should be removed, and several techniques have been used for decades. An innovative method is presented in this paper. The organic impurities were oxidized using a water solution of 1 M peroxynitric acid (PNA). Stainless steel samples were immersed in the solution, and the oxidation of organic impurities was evaluated by the ultra-thin depth profiling using secondary ion mass spectrometry (SIMS). A minute of treatment with PNA caused oxidation of organic impurities and a decrease in the SIMS CN^– signal over an order of magnitude. Prolonged treatment caused the selective removal of the native iron oxide film, leaving a protective film of chromium oxide. Removal of the iron oxide film was also observed when stainless steel was treated with 1 M HNO₃. The PNA method is useful for routine cleaning of stainless steel to remove the organic contaminants from the surface and keep the passive chromium oxide film intact. It is ecologically friendly and enables rapid decomposition of the traces of organic impurities likely to be adsorbed on the metallic surfaces. Full article

Almonds are an essential crop for the economy of California. However, mold and mycotoxin contamination of this commodity has a serious impact on food safety and international trade. The contamination levels of molds and the aflatoxigenic potential of Aspergillus section Flavi isolates were studied on almonds collected at a processing plant in California. The mean total fungal count for 80 samples was 1.0 × 10⁴ CFU/g, while 62 samples (77.5%) had a total mold count less than 1.0 × 10⁴ CFU/g. The most common fungal contaminants were Aspergillus section Nigri (100% of samples), followed by Penicillium (57.5%) and Cladosporium (52.5%) species. Rhizopus, Fusarium and Alternaria spp. were less frequent. A total of 26 A. section Flavi strains were identified, with most strains (23) belonging to the L morphotype of A. flavus. In addition, two S morphotypes of A. flavus, and one A. tamarii strain were observed. Other Aspergillus species, including A. terreus and A. ochraceus were rare. High Performance Liquid Chromatography (HPLC) analysis revealed that 9 out of 13 isolated A. flavus strains produced aflatoxin B₁ (AFB₁) on yeast extract sucrose media. The highest levels of AFB₁ were produced by two A. flavus isolates belonging to the S morphotype (78 and 260 µg/kg). Increasing temperatures and drought conditions may change the population dynamics of toxigenic mold strains on almonds, emphasizing the need to continue monitoring these fungal populations. Full article

Soil toxicity resulting from either natural or anthropogenic heavy metal contamination was evaluated through a nitrifying bacteria bioassay focused on the inhibition of oxygen consumption. Every contaminated soil sample inhibited the nitrifying bacteria bioassay, with inhibition levels ranging from 71% to 100%. The optimal conditions for maximizing O₂ consumption during the test procedure were established as follows: a test culture volume of 1 mL, a soil sample weight of 1 g, a rotation rate of 100 revolutions per minute, and a reaction duration of 48 h. In low- or uncontaminated soils, oxygen consumption ranged from 3.2 mL to 3.0 mL from a headspace volume of 1 mL filled with O₂. In contrast, contaminated soils exhibited a lower range, with values between 0.1 mL and 1.0 mL. EC50 levels for NB O₂ consumption were: Cr⁶⁺ 1.21 mg/kg; Cu²⁺ 6.92 mg/kg; Ag⁺ 8.38 mg/kg; As³⁺ 8.99 mg/kg; Ni²⁺ 10.35 mg/kg; Hg²⁺ 11.01 mg/kg; Cd²⁺ 31.33 mg/kg; Pb²⁺ 129.62 mg/kg. Values for inherent test variability (CVi), variation resulting from the natural characteristics of soil (CVns), and minimal detectable difference (MDD) were found to range between 1.6% and 4.7%, 7.8% and 14.6%, and 2.9% and 5.9%, respectively. A 10% toxicity threshold was set as the maximal tolerable inhibition (MTI) for effective soil toxicity assessment. Nitrifying bacteria bioassays offer a fast, affordable, and user-friendly tool for real-time soil toxicity assessment, boosting soil health monitoring and ecosystem protection. Full article

The contamination of ground and surface waters with micropollutants like estrogenic compounds and genotoxins is a major public health concern. Conventional wastewater treatment plants are currently not capable of completely removing those contaminants. In this study, we applied planar bioassays to investigate the genotoxicity and estrogenic activity of hospital and municipal wastewater from an Austrian treatment plant. Using the open-source 2LabsToGo platform in combination with the HPTLC-SOS-UmuC and HPTLC-YES assays, both genotoxic and estrogenic compound zones were detected in untreated wastewater. Genotoxic activity was found in sewage sludge filtrate and hospital wastewater, with bioanalytical concentrations ranging from 1.6 to 21.8 µg 4-NQO-EQ L⁻¹. Estrogenic responses were observed in the influent and hospital wastewater samples, with BEQ values between 3.5 and 16.0 µg E2-EQ L⁻¹. No activity was detected in the treated effluent, indicating efficient removal of these compounds during wastewater treatment. These results confirm the presence of biologically active micropollutants in hospitals and raw wastewater and demonstrate the suitability of planar bioassays for sensitive, spatially resolved detection. The use of portable equipment like the 2LabsToGo system suggests that on-site monitoring of estrogenic and genotoxic activities in wastewater is feasible and could support routine surveillance of treatment efficiency. Full article

This study evaluates the risk of toxic heavy metal exposure in 20 commonly consumed seafood species from Thailand, focusing on arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb). Seafood is nutritionally valuable but may accumulate harmful metals due to environmental contamination from industrial, agricultural, and medical sources. Samples were collected from markets in Chonburi, prepared through boiling, frying, and grilling, and analyzed using ICP-MS/MS. Most toxic metal levels were within Thai regulatory limits; however, Wedge shell and Musk crab showed arsenic concentrations exceeding permissible levels. Risk assessment employed hazard quotient and margin of exposure calculations using consumption data stratified by age and cooking methods. Results demonstrated that arsenic presents the highest risk, particularly for children aged 0–5.9 years, with Wedge shell and Musk crab posing significant concerns. Cadmium and mercury generally posed low or no risk across samples, except for isolated high-level cadmium exposure in Wedge shell and occasional mercury concerns. Lead, based on the margin of exposure assessment, showed significant health risk for eater only group. The study concludes that although arsenic contamination in certain seafood species requires careful monitoring and public awareness, other toxic metals—particularly cadmium, mercury, and lead—currently present minimal health risks. Routine surveillance of seafood contaminants is essential to safeguard consumer health, particularly among vulnerable groups. Full article

The Black Sea is a semi-enclosed basin subject to intense anthropogenic pressures and transboundary pollution, making reliable and comparable monitoring data essential for large-scale environmental assessments. However, national practices differ considerably, hindering data integration and coordinated reporting under international frameworks. This study, conducted within the Horizon 2020 project “Advancing Black Sea Research and Innovation to Co-develop Blue Growth within Resilient Ecosystems” (BRIDGE-BS), evaluated pollutant surveillance methodologies with a focus on heavy metals and priority organic contaminants (polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorine pesticides). Standard Operating Procedures (SOPs) were collected from institutions across Black Sea countries and systematically compared for water, sediment, and biota matrices. The analysis revealed shared reliance on internationally recognized techniques but also heterogeneity in sediment fraction selection, digestion and extraction conditions, instrumental approaches, and quality assurance/quality control (QA/QC) documentation. To complement this assessment, an intercalibration (IC) exercise was organized through the QUASIMEME proficiency testing scheme, accompanied by a follow-up structured questionnaire sent to participant institutions. While individual results remain confidential, collective feedback highlighted common challenges in calibration, blank correction, certified reference materials (CRMs) availability, digestion variability, instrument maintenance, and the reporting of uncertainty and detection limits. Together, these findings confirm that harmonization in the Black Sea requires not only improved comparability of laboratory methods but also the future alignment of assessment methodologies, including indicators and thresholds, to support coherent, basin-wide environmental evaluations under regional conventions and EU directives. Full article

Plant-based meat (PBM) products have rapidly grown in popularity due to increasing consumer demand for sustainable, ethical, and health-oriented food alternatives. However, these novel products may pose microbiological risks similar to traditional meats, including contamination by Salmonella spp. In this study, PBM samples (n = 63), including raw products (ground pork, mushroom, and burger) and cooked products (chicken tender, chicken breast, nugget, and beef), were collected from local retail markets in Bangkok, Thailand. The prevalence of Salmonella spp. was assessed by calculating the proportion of confirmed positive samples relative to the total number of PBM products tested. Additionally, the genomic characteristics and antibiotic susceptibility of Salmonella isolated from PBM were also investigated. From the result, Salmonella enterica was detected in 2.44% (1/41) of raw PBM samples, whereas no contamination was observed in cooked PBM products (0/22). Serovar identification revealed the isolate to be S. Anatum. Whole genome sequencing (WGS) analysis revealed the genome of S. Anatum SPBM3 consisted of 4,726,256 base pairs with 52.15% GC content, encoding 4717 coding sequences (CDS). Pangenomic analyses placed S. Anatum SPBM3 within a distinct sub-cluster closely related to pathogenic Salmonella strains previously reported, confirming its identity as part of the S. enterica lineage. The genome harbored 67 antimicrobial resistance genes, 5 prophage elements, and 305 key virulence determinants. Phenotypically, the isolate exhibited susceptibility to most tested antibiotics but showed intermediate resistance to streptomycin, ciprofloxacin, and colistin. Our findings highlight the potential microbial risks associated with PBM products and emphasize the importance of genomic surveillance to ensure food safety and public health protection as dietary preferences evolve toward non-traditional food matrices. Full article

This study assessed mycotoxin contamination in roasted peanut snacks and kluiklui (fried pressed peanut cake), and consumer exposure in southern Benin. Roasted peanut snacks and kluiklui were sampled from markets across six municipalities, and their production follow-up was conducted on two sites using different processing methods. Mycotoxins were quantified using UPLC-MS/MS, while fungal species were identified via culture-based methods. Exposure to aflatoxin B1, total aflatoxins and ochratoxin A was estimated. Aflatoxin B1 predominated, reaching 169 µg/kg in roasted peanut snacks and 2144.64 µg/kg in marketed kluiklui. In contrast, just-produced kluiklui contained much lower levels (11.73–37.78 µg/kg). Aspergillus flavus and Aspergillus niger predominated in kluiklui from the first processing site, while Aspergillus chevalieri dominated in kluiklui from the second processing site. The grinding step (using public grinder) was identified as the main contamination point. The significative higher mycotoxin levels in kluiklui sampled on markets compared to just-produced kluiklui are probably due to poor storage conditions. Dietary exposure estimates revealed that margins of exposure for aflatoxins were far below the safety threshold of 10,000, and liver cancer risk estimates were particularly high for kluiklui consumers. Kluiklui consumption poses a significant health risk in Benin. Improved hygiene in public grinders and better storage practices are urgently needed to reduce contamination and protect consumers’ health. Full article

Currently, few studies have revealed the comprehensive effects of environmental organic matter, freeze–thaw and oxidative aging on the adsorption performance of cadmium (Cd(II)), which is essential for the sustainable stability evaluation of the adsorbent. Herein, we observed that humic acids (HAs) extracted from different soils inhibited the adsorption performance of Cd(II) onto the cuttlebone-derived samples by occupying the different major adsorption active sites of the adsorbent, and the lower cadmium-complexation ability of HAs would increase the occupation of adsorption sites. The freeze–thaw process increased the pore size and volume of the cuttlebone-derived samples, while oxidative aging enhanced the specific surface area and introduced additional C–O/C=O groups. These changes promoted the adsorption performance of Cd(II) in the cuttlebone-derived samples after freeze–thaw or oxidative aging. Additionally, the resistances of cuttlebone-based adsorbents to HAs, freeze–thaw, and oxidative aging were elucidated and optimized by simple alkali boiling or carbonization treatment. Furthermore, the adsorption capacities of Cd(II) by samples in the natural cadmium-contaminated river ranged from 548.99 mg g⁻¹ to 571.55 mg g⁻¹, which are higher values than those of most reported adsorbents. Therefore, this work provides an important experimental basis for the practical application and sustainable design of adsorbents under real environmental conditions. Full article