Search Results (201)

In this study, Sr_0.95Bi_0.05TiO₃ was synthesized via solid state reaction, characterized, and applied as a visible-light-active photocatalyst for the degradation of oxytetracycline, imidacloprid, and their mixture. To evaluate the influence of the aqueous matrix on pollutant degradation, photocatalytic experiments were carried out in both distilled water and a real environmental sample (surface water). The Sr_0.95Bi_0.05TiO₃ perovskite showed high photocatalytic performance under visible light, achieving nearly complete degradation of oxytetracycline after 2 h, and significant removal of imidacloprid in river water (60% after 3 h). Enhanced degradation in surface water was attributed to favorable ionic composition and pH. The perovskite oxide maintained its photocatalytic performance over five consecutive cycles, with no significant loss in photocatalytic activity or structural and morphological stability. Ecotoxicological assessment using Daphnia magna confirmed that the treated water was non-toxic, indicating that no harmful byproducts were formed. Complementary Density Functional Theory calculations were conducted to complement experimental findings, providing insights into the structural, electronic, and optical properties of the photocatalyst, enhancing the understanding of the degradation mechanisms involved. This integrated approach, combining experimental photocatalytic performance evaluation in different matrices, ecotoxicity testing, and theoretical modeling, highlights Sr_0.95Bi_0.05TiO₃ as a promising, stable, and environmentally safe photocatalyst for practical wastewater treatment applications. Full article

Waste tires (WTs) constitute a potentially significant source of pollution, and the large quantities that are disposed of require proper handling. Pyrolysis has emerged as an environmentally friendly and effective method for WT treatment. In the present study, the cyto-genotoxic and toxic effects of untreated and acid-treated pyrolytic tire char (PTC_UN and PTC_AT, respectively) were investigated. The cytokinesis block micronucleus (CBMN) assay, using human lymphocytes, and the Aliivibrio fischeri bioluminescence assay were used for the assessment of cyto-genotoxicity and ecotoxicity, respectively. According to the results, both PTC_UN and PTC_AT exhibited genotoxicity at all concentrations tested (2.5, 5, and 10 μg mL⁻¹), which was more pronounced in the case of PTC_AT. Cytotoxicity induction was reported for PTC_UN and PTC_AT at all concentrations. Both demonstrated a relatively low potential for ecotoxicity induction against A. fischeri. Since the cyto-genotoxic and toxic effects of PTC_AT seemed to be more pronounced, the toxic profile of tire char should be investigated in depth before selecting the appropriate applications, thereby avoiding detrimental effects in the environment and humans alike. Full article

Background: The present work is devoted to the biological effects of sol–gel-derived silica (Si)–copper (Cu) nanomaterials. Methods and Results: Tetraethyl orthosilane (TEOS) was used as a silica precursor; copper was introduced as a solution in ethanol with Cu(OH)₂. The obtained samples were denoted as Si/Cu (gel) and Si/Cu/500 (500 °C heat-treated). Their phase formation and morphology were studied by XRD and SEM. The antibacterial activity was tested by two Gram-positive bacteria, three Gram-negative bacteria, and two types of eukaryotic species. Most bacteria were more sensitive to Si/Cu/500 materials than to Si/Cu (gel). The yeasts were more sensitive to Si/Cu (gel). The new nanomaterials were tested for oxidant activity at pH 7.4 (physiological) and pH 8.5 (optimal) in three model systems by the chemiluminescent method. They significantly inhibited the generation of free radicals and ROS. This result underlines their potential as regulators of the free radical processes in living systems. The epithelial tumor cell lines appeared more sensitive than the non-transformed fibroblasts, likely due to their metabolic activity and proliferation rates, leading to greater accumulation of the substances. Using Daphnia magna, the ecotoxicity study showed that the LC₅₀ was reached at 1 mg/L of Si/Cu/500. Si/Cu (gel) was more toxic. Conclusions: Our results reveal the potential of these nanohybrids to be applied in living, eukaryotic systems. The cytotoxicity evaluation showed higher tolerance of normal, non-transformed cells, in concurrence with the oxidation tests. Full article

Long-chain per- and polyfluoroalkyl substances (PFASs) have been the standard active chemicals in aqueous film-forming foams (AFFFs or firefighting foams) since the mid-1960s. Some characteristics of PFASs are environmental persistence and bioaccumulation. Non-fluorinated firefighting foams are an alternative to potentially reducing the ecological/environmental impact of PFAS-based AFFF. We used northern bobwhite (NOBO, Colinus virginianus) to test the ecotoxicity of one candidate (non-fluorinated) foam. Fomtec Enviro USP is a fluorine-free commercial AFFF used primarily for extinguishing Class B hydrocarbon fuel fires. Following a photostimulation phase to initiate egg laying, breeding pairs were exposed for 60+ days to 0.01%, 0.1%, and 0.25% Fomtec in drinking water. The endpoints of the study included survival, growth, and reproductive output. Water consumption was evaluated and used to determine the average daily intake (ADI) based on Fomtec components: sodium dodecyl sulfate or SDS (0.05, 0.15, and 0.32 mg/kg/day for the 0.01%, 0.1%, and 0.25% Fomtec exposures, respectively) and diethylene glycol monobutyl ether or DGMBE (0.49, 6.54, and 18.37 mg/kg/day for the 0.01%, 0.1%, and 0.25% Fomtec exposures, respectively). Over the 60 days, control females laid an average of 59 ± 0.8 eggs compared to 28 ± 9 (0.01% Fomtec exposure), 51 ± 4 (0.1% Fomtec exposure), and 56 ± 2 (0.25% Fomtec exposure); the number of eggs produced per hen was affected by exposure to the lowest Fomtec concentration. Hatching success was not significantly different among treatment groups, and it was within normal reproduction parameters for quail. Our findings in this avian model help to fill data gaps for non-fluorinated foam products, many of which have little toxicological information. Full article

Tissue preservation plays an essential role in biomedical research and histopathological applications. Traditional methods, despite their efficiency, are associated with compromised long-term tissue integrity and probable ecotoxicities. This study explores the application of silver nanoparticles (AgNPs), known for their antimicrobial properties, as a potential tissue preservative. In this work, AgNPs were synthesized via a chemical reduction method. Heart, liver, and kidney tissues were obtained from BALB/c mice and preserved using 10% neutral buffered formalin (NBF) and AgNPs solution for 72 h. Preservation efficiency was assessed by quantifying and measuring DNA and RNA integrity, evaluating protein stability, and conducting histopathological examinations. This study aimed to compare the performance of AgNPs against 10% NBF across these parameters to determine their suitability as an alternative fixative. Our results showed that AgNPs solution maintained consistent DNA, RNA, and protein concentrations/quality across all tissues over 72 h, whereas formalin treatment led to degradation over time. Conversely, 10% NBF demonstrated better preservation of tissue morphology. These results highlighted the differential strengths of each fixative, with AgNPs excelling in molecular preservation and NBF in structural integrity. Overall, AgNPs exhibited superior qualitative and quantitative preservation of nucleic acids and intracellular proteins, indicating their potential as an alternative to formalin for molecular testing. Despite their demonstrated efficacy in biomolecular preservation, further studies are needed to optimize tissue morphology preservation. Full article

China is the world’s leading producer of molybdenum–copper concentrates, an industry noted for its high energy demand and considerable environmental burdens. This study applies a cradle-to-gate life cycle assessment to the production of molybdenum–copper concentrate in the Lesser Khingan Mountains, utilizing the ReCiPe 2016 midpoint method coupled with Monte Carlo uncertainty analysis. The results indicate that human carcinogenic toxicity represents the greatest environmental risk, followed by marine and freshwater ecotoxicity. Contribution analysis reveals that the grinding stage is the dominant impact driver—particularly due to hexavalent chromium emissions—affecting carcinogenic risk, climate change potential, and fossil resource depletion. Scenario testing demonstrates that upgrading grinding technology, enhancing electricity efficiency, and substituting conventional energy with renewable sources can markedly mitigate these impacts. However, because of implementation barriers, such as high capital costs, retrofit downtime, and uncertainties in the supply chain, a pilot phase is necessary before deployment at full scale. Quantitatively, the production of one tonne of molybdenum–copper concentrate corresponds to 0.05 DALYs of human health damage, 1.11 × 10⁻⁴ species.year of ecological loss, and USD 3488.82 of resource depletion. These results provide constructive references for the sustainable development of the mining industry and contribute to achieving China’s dual carbon targets through energy transformation and low-carbon technological innovation. Full article

Micro- and nanoplastic pollutants are among the major environmental challenges, and are exacerbated by the continuous degradation of growing amounts of plastic debris in the aquatic environment. The purpose of this study was to investigate the morphology of micro/nanoplastics (M/NPs) formed from polyethylene terephthalate (PET) by mechanical degradation in an aquatic environment, which mimics the processes in the natural environment well, and to determine the impact of these particles on model aquatic organisms. To this end, M/NPs were obtained by ball milling in an aqueous medium and the effect of milling length on particle size and shape was investigated. The particles obtained in an environment simulating natural conditions were irregularly shaped, and those of nanometric size tended to form aggregates of various shapes. The ingestion and toxicity of PET M/NPs to freshwater zooplankton were then assessed. Daphnia magna and Thamnocephalus platyurus were used in a series of acute ecotoxicity tests, by exposure to M/NP dispersions at environmentally realistic concentrations (0.01–1.0 mg/L), as well as at very high concentrations (100–1000 mg/L). A significant uptake of PET particles by both types of invertebrates was observed, and the M/NPs were mainly concentrated in the digestive tracts of the crustaceans. However, they did not cause acute toxicity to the tested organisms or a reduction in their swimming activity, even at concentrations as high as 1000 mg/L. Full article

The presence of contaminants of emerging concern (CECs) in agricultural and fisheries water has raised significant environmental and health concerns. Vacuum membrane distillation (VMD) has shown promise as an effective method for removing non-volatile contaminants, such as CECs, from water. This study presents a novel application of a bench-scale VMD unit to treat water from Lagoa da Conceição, Florianópolis, Brazil, using microporous membranes (0.22 µm) under the following optimized conditions: 75 °C, a flow rate of 24 L·h⁻¹, and a vacuum pressure of −640 mmHg. The system demonstrated remarkable performance in removing several key antimicrobials, including sulfamethoxazole, ciprofloxacin, azithromycin, and clindamycin (500 μg·L⁻¹), with rejection rates of 99.1%, 98%, 99.9%, and 99%, respectively, and an average flux of 7.08 L·m⁻²·h⁻¹. Additionally, the VMD unit achieved a substantial 99.98% salt rejection. Ecotoxicity tests revealed low toxicity for sulfamethoxazole, ciprofloxacin, and azithromycin but high toxicity for clindamycin, while human risk assessment indicated moderate-to-high risks for ciprofloxacin and clindamycin. The findings highlight the potential of VMD as an effective and sustainable technology for the removal of CECs and biocompounds, enhancing water safety and reducing environmental hazards. This study offers a promising solution for addressing water contamination on a broader scale. Full article

Although the coking industry is a major polluter, it is still an important and irreplaceable industry in many countries. Wastewater from the coking industry typically contains large amounts of various hazardous substances, including phenols, cyanides, and thiocyanates; we conducted a comprehensive study on their ecotoxicity. This included five different toxicity tests with common species from different trophic levels: the bacteria Aliivibrio fischeri and Pseudomonas putida, the microalgae Chlorella sp., the duckweed Lemna minor, and the onion plant Allium cepa. These tests have rarely or never been used for these three toxicants. The results show that cyanide generally has the highest toxicity, while phenol has a relatively equal or higher toxicity than thiocyanate, depending on the test. Since no data on the joint toxic action of these three toxicants can be found in the literature, and although their joint occurrence in the aquatic environment is very likely, we performed joint toxic action analysis. The analysis was performed for binary and ternary mixtures of the toxicants using the Aliivibrio fischeri test. The concentration addition model was used as a reference model for the toxic behavior of these mixtures. The results obtained showed a synergistic deviation from the concentration addition model for combinations of phenol with cyanide and with thiocyanate, while the combination of cyanide and thiocyanate led to additive toxic behavior. Full article

Endocrine disruptors such as 17α-ethinylestradiol pose significant ecological risks in aquatic environments. This study assessed the catalytic performance of Fe- and Cu-impregnated delaminated clays (DCs) and layered double hydroxides (LDHs) in a Fenton-like process for EE2 removal. The effects of key parameters—including hydrogen peroxide concentration, initial contaminant load, and catalyst dosage—were analyzed using HPLC-QqTOF. Delaminated clays (DCs) demonstrated higher removal efficiencies compared to layered double hydroxides (LDHs), reaching 55% with Fe and 47% with Cu, while LDHs achieved 40% and 33% for Fe and Cu, respectively. Ecotoxicity was evaluated using bioassays (L. sativa, S. capricornutum, D. magna) and the Ames test. Notably, S. capricornutum exhibited 100% inhibition at the highest tested concentration, with IC₅₀ values of 11.2–12.4 for Cu and 31.5–32.7 for Fe. L. sativa was inhibited by Cu- and Fe-impregnated LDH/DC, with IC50 values of 71.0 (DC-Cu), 56.6 (DC-Fe), and 58.6 (LDH-Fe). D. magna exhibited 17–75% mortality when exposed to untreated EE2, while LC50 values confirmed Cu’s greater toxicity. The Ames test indicated no mutagenic effects. Integrating the Fenton-like process with complementary techniques is recommended to enhance efficiency. These findings highlight the need to optimize operational parameters for effective removal of 17α-ethinylestradiol. Full article

This study investigates the activation mechanisms of hydrogen peroxide (H₂O₂) using iron-activated carbon (Fe²⁺/H₂O₂/AC) for the efficient degradation of amoxicillin (AM) in wastewater. The system achieved a high degradation efficiency of 90% under alkaline conditions (pH 9), with singlet oxygen (¹O₂) and hydroxyl radicals (^•OH) identified as the dominant reactive species through scavenger experiments. High-performance liquid chromatography–mass spectrometry (HPLC-MS) analysis revealed degradation by-products and proposed reaction pathways, including the loss of amine groups, ring-opening oxidation, and bond cleavage. The structural and morphological properties of Fe²⁺/H₂O₂/AC were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer–Emmett–Teller (BET) analysis. The BET surface area of Fe²⁺/H₂O₂/AC was determined to be 128.36 m²/g, with a mesoporous structure facilitating efficient mass transfer and adsorption. The system was systematically evaluated under varying conditions, including H₂O₂ concentration (25–250 mg/L), catalyst dosage (0.05–1.0 mg/L), and pH (3–10). Kinetic analysis revealed that the degradation process follows pseudo-second-order kinetics (R² = 0.966), while adsorption isotherms were best described by the Langmuir model (R² = 0.98). Ecotoxicity tests indicated that the degradation products are less harmful to aquatic organisms. The system demonstrated excellent stability over three consecutive cycles, highlighting its potential for long-term application in treating pharmaceutical-contaminated wastewater. Full article

This study aimed to evaluate the degree of contamination of water matrices (deionised water, spring water, tap water) in a 14-week experiment using film samples from commercial bags printed with water- and solvent-based inks. The effect of different lighting conditions on leaching and ecotoxicity was also investigated. Samples were exposed for 24 h to natural sunlight and to no light in a darkroom. A significant increase in contaminants in the aqueous matrices was observed in regard to the 12-week leaching potential of the components from the films in regard to all the lighting variants and aqueous matrices analysed: an increase in dissolved organic carbon (DOC), total organic carbon (TOC), and total suspended solids (TSS). Based on the procedures carried out, the relationship between the lighting conditions and the amount of the constituents released into the aqueous matrices was not confirmed. The concentration of total organic carbon in all the samples peaked between weeks 6 and 9 of the study, followed by a gradual reduction in leaching. This phenomenon could be linked to the gradual depletion of the substances present in the samples or to the achievement of a concentration equilibrium between the aqueous matrix and the sample and/or to the formation of deposits on the surface of the films, which hindered the migration of the substances into the solutions. Ecotoxicity tests performed between 7 and 14 weeks showed most samples’ toxic and highly toxic effects on the growth of Lemna minor fronds and Sinapis alba/Lepidium sativum roots. In contrast, no toxic effects were observed in regard to most of the samples during screening mortality tests on Daphnia magna and Artemia salina. This study highlights the need for further research into the effects of plastic pollution on the aquatic environment. Full article

Citric acid (CA), a naturally occurring compound in fruits, mainly citrus, has gained attention for its eco-friendly potential in wood modification. Through esterification, citric acid reacts with wood polymers to form bonds that improve adhesion, dimensional stability, and durability while reducing moisture absorption and susceptibility to decay. This study evaluated the efficacy of CA as an eco-friendly wood treatment. Wood samples were treated with solutions at varying concentrations (5%, 10%, and 15%) and assessed for dimensional stability, mechanical properties, biological resistance, and ecotoxicity. CA treatments significantly improved dimensional stability, with higher concentrations yielding greater weight percent gain (WPG) and anti-swelling efficiency (ASE). Biological tests demonstrated exceptional termite resistance, with no survival and minimal mass loss in treated samples at higher concentrations. Similarly, fungal resistance improved, as citric acid inhibited fungal growth. Ecotoxicity tests showed relatively low phytotoxicity, with some decrease in germination indices (GI) at higher CA concentrations. These findings highlight CA as a sustainable wood treatment for enhanced durability and biodegradation resistance in construction and outdoor applications. Full article

Mining activities often contaminate soils with heavy metals, generating environmental and health risks. This study investigates the ecotoxicity of muddy (Mw) and sandy (Sw) mining wastes on Phaseolus vulgaris and assesses the impact of five locally sourced biochar amendments on plant growth and soil pore water (SPW) properties. Most biochars improved water retention, except for argan nut shells (An) biochar, highlighting the importance of feedstock type. Sw supported better plant growth than Mw regardless of biochar addition, due to textural differences. Palm fronds (Pf) biochar significantly enhanced surface leaf area in Sw. SPW analysis revealed that biochar affected pH and electrical conductivity (EC) differently across soil types. Mw consistently increased pH, while Sw’s pH was biochar-dependent. A significant 5.1-fold EC increase was recorded in Sw amended with Pf. All biochars reduced Pb availability in Mw at planting, while Cu availability decreased in Sw at harvest. In Mw, Pb, Zn, and Cu, uptake and accumulation were unaffected by biochar, while a slight reduction was observed in Sw roots. A germination test with Lepidium sativum confirmed these findings, particularly the inhibition observed with An. This dual approach highlights the toxicity of mining soils and biochars’ potential as amendments for soil remediation programs. Full article

The development of a predictive model for estimating oral acute toxicity (LD₅₀) in wildlife species is essential for environmental risk assessments. In this study, a quantitative structure–activity relationship (QSAR) model was developed to predict the acute oral toxicity of pesticides toward Bobwhite quail, categorizing them into three toxicity classes: low, moderate, and high. This model was built using the SARpy softwareA dataset of pesticides collected from OpenFoodTox and the ECOTOX database was used to identify training and test datasets, while data collected from the PPDB were used as an external validation. The model’s performance was evaluated using these three sets. The accuracy achieved on the training set was 0.75, indicating good performance during model development. However, the model’s accuracy dropped to 0.55 for the test set, suggesting some overfitting. The external validation accuracy was 0.69, reflecting the model’s ability to generalize to new, unseen data. While these results demonstrate the potential of the QSAR models for predicting toxicity in Bobwhite quail, they also highlight the need for further refinement to improve predictive accuracy, particularly for unseen compounds. This work contributes to the development of computational tools for wildlife risk assessment and toxicological predictions. Full article