Journal of Environmental Science and Health Part A-toxic\/hazardous Substances & Environmental Engineering最新文献

Oil pollution poses a serious threat to aquatic ecosystems and water quality, necessitating the development of efficient, selective, and reusable absorbent materials. In this study, cork was chemically modified using deep eutectic solvents (DES) synthesized from nonanoic acid combined with either choline chloride or betaine at a 1:4 molar ratio. To further enhance hydrophobicity, the DES-treated corks were subsequently coated with stearic acid. The successful chemical modification and structural changes were confirmed through comprehensive characterization using Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR), ultra-high resolution scanning electron microscope (UHR-SEM), and thermogravimetric analysis (TGA). The materials were then tested for their oil absorption capacity, reusability, and antibacterial properties. The comprehensive characterization confirmed successful chemical modification and structural changes in the cork material. The DES-treated corks exhibited improved antibacterial activity against Escherichia coli ATCC 25922, showing significant reductions of 23.2% (choline chloride-based) and 47.1% (betaine-based) compared to untreated cork. Absorption tests with engine oil and dichloromethane demonstrated that the betaine-nonanoic acid-treated cork achieved superior performance, with high absorption capacities of 13.92 g g^-1 and 28.15 g g^-1, respectively, and an oil-water separation efficiency of 80.14%. Furthermore, the material maintained high efficiency over 10 reuse cycles with minimal loss in capacity. These findings highlight the potential of DES-treated cork, particularly when coated with stearic acid, as a sustainable and high-performing sorbent for oil spill remediation.

Clopyralid is among the most widely used herbicides worldwide. Discharging clopyralid-contaminated water into the environment can adversely affect human health and ecosystems. Research on the biological treatment of clopyralid-laden wastewater is crucial for enhancing process performance and preventing environmental contamination. This study investigates the biodegradation of clopyralid by an activated sludge (AS) culture to clarify its microbial degradation and inhibition kinetics. Furthermore, the inhibitory effect of clopyralid on isolated AS microorganisms (bacteria and fungi) was examined using paper disk and broth culture methods. The results demonstrate the potential of AS to biodegrade clopyralid. Clopyralid degradation rates increased with increasing herbicide concentration from 50 to 225 mg/L, then declined. At 300 mg/L, clopyralid biodegradation was completely inhibited. Luong's kinetics model for inhibitory substrates accurately described this biodegradation pattern. All cultured bacteria and fungi were inhibited at higher clopyralid doses. However, while most bacteria were inhibited at 1200 mg/L of clopyralid, fungi were inhibited at a 10-fold higher concentration. At this concentration range, clopyralid exhibited a bacteriostatic/fungistatic effect rather than a bactericidal/fungicidal one. That is, it did not cause lethal disruption of essential cellular functions. The findings of this study could inform strategies to enhance clopyralid biodegradation at high concentrations in AS reactors.

Chromium (Cr), classified by the International Agency for Research on Cancer (IARC) as a carcinogen, poses significant risks to human health. This study evaluated the uptake of Cr in Arachis hypogaea, Vigna unguiculata, and Zea mays cultivated in Cr-contaminated soils and assessed the associated toxicological risks to human consumers. A greenhouse experiment was conducted using soils contaminated with Cr at 10 and 30 mg kg^-1. Chromium concentrations in soils and plant tissues were quantified using ICP-OES, and bioconcentration and translocation factors (TFs) were determined to assess Cr uptake and movement within the plants. The lifetime incremental cancer risk (ILCR) was determined to evaluate potential long-term health risks. Results showed that all three species accumulated significant amounts of Cr in roots and aerial tissues, with bioconcentration factors (BFs) greater than one in most treatments. However, TFs remained below or equal to one for most cases, indicating limited upward movement of Cr. Importantly, ILCR values were within permissible limits, suggesting no significant carcinogenic risk for consuming these crops. These findings indicate that A. hypogaea, V. unguiculata, and Z. mays are resistant to Cr contamination and can be safely cultivated and consumed in soils containing up to 30 mg kg^-1 of Cr. This study provides valuable insights for ecotoxicological risks and for the safe management of Cr-contaminated agricultural soils in Mozambican industrial areas.

Groundwater sources such as hand-dug wells remain a primary source of drinking water in many developing regions but are often compromised by turbidity, hardness, and microbial contamination. Conventional disinfection using chlorine is effective but may introduce chemical residuals and disinfection by-products. This study comparatively evaluated the effectiveness of Moringa oleifera seed kernel extract (a natural bio-coagulant with antimicrobial properties) and chlorine (a chemical disinfectant) in improving the physicochemical and microbiological quality of well water. Well water samples were collected from student hostels at the University of Ilorin, Nigeria. Treatments were conducted using Moringa oleifera seed kernel extract at 0.5%, 1.0%, and 1.5% (w/v) and chlorine at 2 mg/L free residual chlorine. Physicochemical parameters (turbidity, pH, total dissolved solids, total hardness, iron concentration) and microbiological indicators (heterotrophic bacteria, fungi, total and fecal coliforms) were analyzed using APHA and WHO standard methods. All analyses were performed in triplicate, and data were subjected to one-way ANOVA (p < 0.05). Moringa oleifera treatment reduced turbidity from 46.5 NTU to 2.8 NTU (>94%), while chlorine reduced turbidity to 6.5 NTU. Complete removal of coliforms and E. coli was achieved at 1.5% Moringa and 2 mg/L chlorine. Moringa demonstrated superior turbidity reduction and more stable pH, while chlorine showed stronger residual disinfectant action. Conclusively Moringa oleifera seed kernel extract is an effective, eco-friendly bio-coagulant capable of significantly improving water quality and achieving microbial safety comparable to chlorine. Its low cost, biodegradability, and local availability make it a viable alternative or complement to chemical disinfection in decentralized water treatment systems, supporting SDG-6.

There are limited studies on air quality in the Southern United States, with even fewer assessing the health impacts of poor air quality on underserved communities. Jackson, the Mississippi state capital, has documented environmental injustices linked to drinking water quality and access to healthcare, but the impact of air pollution is underexplored. Fine particulate matter (PM_2.5), a complex mixture of air pollution, has associations with systemic health effects and the ability to induce oxidative stress. While federal regulations require monitoring PM_2.5 throughout the United States, there is limited characterization of health relevant components, including black carbon and polycyclic aromatic hydrocarbons (PAHs). This project utilizes PM_2.5 filters to investigate the chemical and toxicological profile of PM_2.5 at two intraurban sites using the dithiothreitol assay to measure oxidative potential and Gas Chromatography - Mass Spectrometry to quantify PAHs. Significant differences between sites in PM_2.5 concentration, oxidative potential, and PAH concentrations was observed. Additional research is needed to determine the potential human health risks that PM_2.5 poses to residents in Jackson, MS, but this work highlights pollutants of interest at levels that exceed similar studies for urban regions, encouraging more attention and action to protect the air of vulnerable populations.

This study investigates the optimization of alum dosing in surface water treatment at Ghana's Weija Water Treatment Plant using response surface methodology (RSM). By combining conventional jar tests, historical data (2002-2016) and 2018 seasonal experiments, the research evaluates the impact of raw water quality, especially turbidity, pH, color and polycyclic aromatic hydrocarbons (PAHs), on coagulation efficiency. While traditional jar tests required 90-100 mg/L of alum, RSM achieved better turbidity and color removal with just 71 mg/L, also reducing residual aluminum levels. The RSM approach demonstrated cost savings exceeding GHS 600,000 annually, cutting chemical usage by over 30% and ensuring compliance with WHO standards. Comparative analysis across treatment techniques confirmed RSM's superior performance and economic benefits. The findings highlight the importance of predictive, multivariate optimization in improving treatment reliability, reducing sludge generation and enhancing operational efficiency.

This study investigates the removal of nickel (II) from aqueous solutions using a biodegradable cellulose nanocrystal (CNC) nanocomposite. Fourier Transform Infrared (FTIR) analysis confirmed successful functionalization, with characteristic peaks observed at 1735 cm^-1 (C = O stretching of carboxyl groups) and 1050 cm^-1 (C-O-C stretching), indicating the effective incorporation of EDTA into the CNC structure. Scanning Electron Microscopy (SEM) revealed a rough and porous surface morphology, favorable for enhanced adsorption performance. Thermogravimetric Analysis (TGA) demonstrated the composite's thermal stability up to 320 °C, with a significant weight loss of 65% between 300-400 °C corresponding to cellulose decomposition. Batch adsorption experiments examined the effects of pH, contact time, adsorbent dosage, and initial nickel (II) concentration. The maximum removal efficiency of 98.3% was achieved at a pH of 6, a 120-min contact time, an 8 g/100 mL dosage, and an initial concentration of 150 mg/L. Film diffusion was identified as the rate-limiting step with an R² of 0.983. Machine learning models were also developed to predict adsorption performance. The Artificial Neural Network (ANN) model achieved R² of 0.987 and RMSE of 0.012, while the Adaptive Neuro-Fuzzy Inference System (ANFIS) demonstrated superior accuracy with R² of 0.995 and RMSE of 0.008. The nickel(II) adsorption is best represented by the Langmuir model, with an R² value of 0.996. The pseudo-second-order model governs the adsorption process; the Dubini-Radushkevich model confirms chemisorption with an energy of 9.375 kJ/mol. These findings confirm that the CNC nanocomposite is an efficient, thermally stable, and sustainable adsorbent for Ni(II) removal from aqueous media, with ANN and ANFIS models providing reliable predictive capability for process optimization.

Polyethylene nanoplastics (PE-NPs) are emerging wastewater contaminants that may disrupt biological phosphorus removal (BPR). To assess their effects on BPR, experiments with PE-NPs at 0-20 mg/L were conducted. With increasing PE-NPs, phosphorus removal declined from 96.16% to 83.97% and effluent COD increased from approximately 20-43.04 mg/L. At 20 mg/L PE-NPs, anaerobic PHA synthesis and aerobic PHA consumption were measured at 83.19% and 82.74% of the control values, respectively. Total EPS dropped from 136.78 to 118.26 mg/g MLVSS alongside a minor increase in the PN/PS ratio, and intracellular ROS levels reached about 128% of those in the control. Fluorescence excitation-emission matrix and Fourier-transform infrared spectroscopy analyses indicated a reduction in aromatic protein and microbial by-product signals, alterations in N-H/O-H and amide-I hydrogen bonding environments, and a shift in EPS protein conformation from α-helix to β-sheet/aggregate-rich structures. High-throughput sequencing revealed a microbial community shift, marked by a decrease in phosphorus-accumulating organisms (PAOs, e.g., Acinetobacter and Candidatus Accumulibacter) and an increase in glycogen-accumulating organisms (GAOs, notably Candidatus Competibacter). This shift intensified carbon competition, limiting PAOs energy storage and phosphate uptake. These combined effects-oxidative stress, altered EPS, and microbial shift-decouple carbon-phosphorus metabolism, accelerating BPR deterioration.

To address growing energy demand and promote environmental sustainability, the development of diverse biomass-based renewable energy is crucial. Co-digestion of Chlorella and sludge has been recognized as an effective strategy to improve methane production efficiency from biomass. This study aimed to explore the optimal ratio of Chlorella and sludge. On this basis, hydrothermal pretreatment was applied to the Chlorella-sludge mixture to investigate the temperature effects on co-digestion performance. This step aimed to optimize methane yield and identify the most suitable pretreatment temperature. The anaerobic digestion kinetics were evaluated by fitting experimental data to both the Fitzhugh first-order kinetic model and the Modified Gompertz model. Additionally, metagenome sequencing was performed on samples before and after hydrothermal pretreatment to elucidate the impact of pretreatment on microbial community dynamics during the acidogenesis phase of anaerobic digestion. The experimental results demonstrated that a 20-day co-digestion period with a VS Chlorella to VS sludge ratio of 2:1 yielded the highest biogas production, reaching 250.98 mL/g VS. After 30 min of hydrothermal pretreatment at 180 °C, the co-digestion efficiency of Chlorella and sludge reached the optimal level, with a cumulative methane production of 261.02 mL/g VS, which had a significant impact on microbial diversity.

Free living animals are sensitive indicators of the environment pollution by polychlorinated biphenyls (PCBs) and other organic pollutants. The aim of this study was to determine polychlorinated hydrocarbons in the depot fat of red foxes (Vulpes vulpes L.) living in the natural environment of south-western Slovakia. The analyses performed included dichlorodiphenyltrichloroethane (DDT), hexachlorobenzene (HCB) and polychlorinated biphenyls (PCBs). The gas chromatograph equipped with an electron capture detector (ECD) was used. The accumulation of pollutants in depot fat of animals followed the order PCB > DDT > HCB. Of all pollutants, the total concentration of PCBs was significantly higher (p < 0.05) in fat tissue of foxes (1.445 ± 0.174 mg/kg) in comparison to DDT (0.1120 ± 0.24 mg/kg) and HCB 0.052 ± 0.010 mg/kg). Compared to samples from females (0.962 ± 0.110 m/kg), significantly higher (p < 0.05) PCB levels were found in samples from males (1.751 ± 0.293 mg/kg). Moderate positive correlation (r = 0.5509) between PCB and HCB was detected. Wild animals can act as indicators of environmental pollution by polychlorinated hydrocarbons, making their monitoring an ongoing priority.