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

This study evaluated the toxicological and mutagenic potential of water samples from a Wastewater Treatment Plant (WWTP) in Lavras, Minas Gerais, Brazil. Samples were taken from four sites: upstream in the stream (P1), downstream (P2), at the entrance of the treatment station (P3), and at the exit (P4). We conducted physicochemical analyses in water, phytotoxicity tests on plants (Triticum aestivum, Pennisetum glaucum, Lactuca sativa, Raphanus sativus), cytogenotoxicity tests using onion roots (Allium cepa), and Artemia salina immobilization tests. Elevated Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), anionic surfactants, and ammoniacal nitrogen were found at P3 and P4. While germination rates were generally unaffected, P4 inhibited the germination speed of R. sativus. The growth of L. sativa increased in P3 and P4, and of R. sativus in P2, due to more nitrogen and phosphorus. T. aestivum and P. glaucum, however, had their growth inhibited at P4 due to surfactant toxicity. Cytogenotoxicity tests revealed the highest frequencies of micronuclei and nuclear buds in cells exposed to P3 and P4. Additionally, P3 caused 87.5% immobilization of A. salina. These findings suggest that the WWTP is not fully efficient, and its effluent discharge may contribute to eutrophication and genetic mutations in exposed organisms.

Activated carbon derived from avocado seeds (AVSAC) was evaluated for its ability to adsorb and desorb Thorium(IV) ions, targeting applications in nuclear waste management and environmental cleanup. Extensive characterization (FTIR, XRD, SEM, TGA/DSC, BET) confirmed structural changes upon Th(IV) uptake; notably, FTIR indicated hydroxyl and aromatic groups participate in binding, while SEM and BET showed significantly reduced porosity and surface area, consistent with effective adsorption. At pH 3.0, a fixed-bed column (0.50 g AVSAC; flow rate 0.25 mL min^-1; residence time 4 min mL^-1) treated 50 mL of 750 mg L^-1 Th(IV), achieving 97.3% removal (36.5 mg captured; 73 mg g^-1 working capacity). The adsorption was remarkably fast, sequestering 94% of Th(IV) within five minutes. Kinetic data fit a pseudo-second-order model well, and equilibrium data aligned with the Freundlich isotherm, consistent with PSO behavior on a heterogeneous surface; overall uptake is predominantly physical (thermodynamics/D-R), with localized Th-O coordination contributions. Thermodynamic analysis revealed a spontaneous and endothermic process. Regeneration studies showed that 1.00 M nitric acid could recover 70.5% of the adsorbed thorium. Overall, this work highlights AVSAC as a highly promising, efficient, and regenerable adsorbent for removing Th(IV) from aqueous solutions, offering valuable insights for treating contaminated water streams.

Mercury (Hg) contamination in soil is a serious environmental and health concern due to its high toxicity and bioaccumulation. This study investigated the potential of rice husk biochar (RHB), bamboo biochar (BB) and tyre-modified biochar (T-RHB and T-BB) for mitigating Hg contamination. Biochar was produced through pyrolysis of agricultural residues at 500-550 °C and characterized for surface area, elemental composition, functional groups using BET, CHNS, FTIR and SEM-EDS analysis. The results showed that Hg removal followed a chemical adsorption process. Tyre-modified biochar was more effective in removing Hg, with T-BB and T-RHB adsorbing 82.64 mg/g and 47.62 mg/g of Hg, which was much higher than the unmodified BB (38.46 mg/g) and RHB (32.36 mg/g). The Langmuir model indicated monolayer adsorption with higher Q_max and K_L values, showing stronger Hg binding on modified biochar. TCLP tests revealed that tyre-modified biochar reduced Hg leaching by 85% (T-BB) and 72% (T-RHB) compared to untreated soil. Even under different pH conditions, the modified biochar maintained high Hg-binding efficiency, especially near neutral to slightly alkaline conditions (pH 7.3-9.6). Overall, tyre-modified biochar offers a cost-effective, eco-friendly and sustainable way to stabilize Hg in contaminated soil while turning waste tyre powder and agricultural residues into useful materials.

Microplastics (MPs) are emerging environmental contaminants that pose significant risks to ecosystems and human health. Traditional detection methods for microplastics in water and other matrices often involve complex and costly techniques. In this research, we introduce an innovative approach utilizing carbon quantum dots (CQDs), a class of fluorescent nanomaterials known for their simple synthesis, low cost, eco-friendliness, and low toxicity. MPs were successfully stained with CQDs by optimizing the reaction conditions through a microwave-assisted synthesis. The resulting MP-CQD composites were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), profilometry, and UV-Vis analysis. This study further investigated the fluorescence emission from CQD-stained MPs and examined the impact of MP concentration on particle agglomeration. This novel method demonstrated the ability to effectively agglomerate and detect MPs at very low concentrations, offering a streamlined and efficient approach to MPs detection in water. The optimized method enabled visible fluorescence detection of MPs at concentrations as low as 0.005 ppm, demonstrating sensitivity comparable to instrumental approaches but with greater simplicity and accessibility. The integration of CQDs into this process marks a significant advancement in detecting and potentially removing MPs from aquatic environments.

Polyvinyl alcohol (PVA) wastewater was pretreated by iron-carbon (Fe/C) microelectrolysis. The effects of initial pH, reaction time, aeration volume, and iron-carbon dosing on chemical oxygen demand (COD) removal rate were investigated. The COD removal rate is used as the response function and the response surface method (RSM) is optimized. When the initial pH was 1.8, the reaction time was 2.5h, the aeration volume was 4.3 L/min, and the treatment concentration was 800 mg/L of polyvinyl alcohol wastewater, the COD removal rate was the highest, 62.26%, and the PVA removal rate reached 64.88%. Among them, reaction time and aeration volume are key factors in improving the treatment effect. Research shows that after pretreated PVA wastewater is treated by a microelectrolytic reactor, the organic pollutants in the wastewater can be basically completely degraded or converted, and the biochemical properties of the wastewater can be improved.

Mining-induced heavy metal pollution poses an urgent ecological challenge. Recently, biochar, especially corn stover biochar (CSB) modified with ionic liquids (ILs) for weak interactions, has shown promise in mine water remediation. In this study, we used charred corn stover as biochar and synthesized 1-methyl-3-[3-(trimethoxysilyl) propyl] imidazolium IL as modifier to create imidazolium-based IL-modified biochar. The chemical structure of the IL and the chemical composition of the biochar were analyzed with the help of ¹H NMR and FT-IR. Characterization techniques such as XPS, SEM, and nitrogen adsorption-desorption measurements were employed to investigate the elemental composition, surface morphology, pore size, porosity, and other physicochemical properties of the corn straw biochar. Cd²⁺ was chosen as the representative of heavy metal ions in mine water, and the adsorption kinetics and isotherm experiments were conducted to study the adsorption performance of CSB on heavy metal ions. The results exhibited that the adsorption performance of IL-modified CSB material (Q_e = 48.1000 mg/g) for heavy metals was enhanced to a certain extent compared with that of unmodified CSB material (Q_e = 44.0000 mg/g). This provided a foundation for using corn straw biochar to remove heavy metals in mine water.

Wastewater from pharmaceutical industries has made pharma industries as one of the major emerging pollutants. In this study, physicochemical parameters were evaluated, and potentially toxic elements (PTEs) were analyzed by ICP-AES. LC-MS revealed the presence of various organic pollutants including antibiotics (Levofloxacin, Kanamycin, Streptothricin F), anticancer drugs, β-blockers, hormones, NSAIDs, psychiatric drugs, and CNS stimulators, among other PPCPs. The cyto-genotoxic potential of wastewater was evaluated using Allium cepa chromosomal aberration assay. Toxicity was measured through mitotic index and chromosomal aberration after treatment with different concentrations (v/v) of wastewater. Significant increase in chromosomal abnormalities and decrease in mitotic index with increasing concentration of effluent was observed. The lowest MI was recorded (7%) at 100% concentration of wastewater. Furthermore, to assess phytotoxicity Vigna radiata seed germination assay was performed and found that the number of seeds germinated and other parameters such as seedling vigor index, radical and plumule length significantly decreased when treated with different concentrations of wastewater. Oxidative stress was shown in Vigna radiata root by Confocal Laser Scanning Microscope. This study highlights the toxicological risk posed by pharmaceutical wastewater due the presence of various PPCPs and PTEs which might be toxic and adversely affect human health, plants as well as environment.

Chronic Kidney Disease of unknown etiology (CKDu) is a major public health concern in the North Central Province (NCP) of Sri Lanka, where groundwater heavy metal contamination is suspected as a key contributing factor. This study investigates the mobilization and transport of in-situ heavy metals in agricultural soils from Medawachchiya and Horowpathana and examines the movement of artificially introduced Cadmium and Lead through soil column experiments. Four locally available, low-cost bio-adsorbents namely, Mahogany sawdust (MG-A), Jackfruit peels (JF-A), Rice husk (RH-A), and Coconut husk (CH-A) were evaluated for Cd²⁺ removal from synthetic groundwater. Among them, MG-A demonstrated the highest adsorption efficiency (73.12% for 80 mg/L and 92.2% for 10 mg/L), outperforming JF-A (60.07%), RH-A (36.73%), and CH-A (16.54%). Adsorbent characterization using FTIR, FE-SEM, and BET analyses revealed that surface functionality and porosity played key roles in adsorption performance. Regeneration studies showed that acid (HCl) treatment restored the adsorption capacity of MG-A by 91.49%, indicating strong reusability potential. The novelty of this research lies in integrating soil transport experiments with bio-waste-derived adsorbent development, providing a comprehensive understanding of heavy metal mobility and remediation. These findings demonstrate a sustainable, community-adaptable approach for mitigating Cd²⁺ contamination in groundwater, offering practical and scalable solutions to reduce CKDu risks in vulnerable regions.

The spatial-temporal evolution of six key air pollutants (PM_2.5, PM₁₀, CO, NO₂, SO₂, O₃) across 337 Chinese cities between 2015 and 2023 was analyzed based on the provided figure set. The period represents a critical juncture encompassing the implementation and intensification of China's ambitious national air pollution action plans. Using annual average concentration data visualized through spatial mapping, we conducted a comparative analysis of pollutant distributions for 2015, 2020, and 2023, identifying regional hotspots and temporal trends. Significant reductions were observed for most pollutants: PM_2.5 decreased by 46.3% in the Beijing-Tianjin-Hebei (BTH) region and by 24.5% in the Fenwei Plain (FWP); SO₂ declined by over 79% in BTH and FWP; CO fell by 62.9% in BTH. NO₂ showed slower reductions, particularly in urban corridors, highlighting persistent traffic-related emissions. However, O₃ increased by 14% in BTH and 12% in the Yangtze River Delta (YRD), with over 50% of BTH cities exceeding 180 μg/m³ by 2023, highlighting the complex atmospheric chemistry involved. The analysis underscores the effectiveness of targeted policy interventions for primary pollutants but emphasizes the urgent need for multi-pollutant, regionally tailored strategies to address the evolving air quality landscape, particularly the rising O₃ threat.

Microplastics (MPs) have emerged as a noteworthy environmental concern due to their pervasive presence and potential ecological impact. This study investigates the degradation of three commonly used plastics-polyethylene (PE), polypropylene (PP), and Nylon-6 (N6) under artificial aging conditions mimicking natural sunlight exposure and chemical oxidation in seawater. MP pellets were exposed to varying concentrations of hydrogen peroxide (H₂O₂) in artificially simulated seawater with controlled temperature at 60 °C, 300 RPM agitation, and UV irradiation. The chemical, morphological, and physical changes in the MP pellets over a 160-h period was characterized with Attenuated Total Reflectance Fourier-Transform Infrared Spectroscopy (ATR-FTIR), Field Emission Scanning Electron Microscopy (FE-SEM), Stereomicroscopy, and Particle size analysis (PSA). The results indicate that the degradation patterns and mechanical stability of the plastics varied based on the polymer type and exposure conditions. The PE exhibited significant degradation characterized by the formation of hydroxyl and carbonyl groups along with surface roughening and mechanical instability. The PP showed less degradation compared to PE attributed to its higher melting point and UV stability. The N6 displayed intermediate degradation influenced by amide linkages and mechanical strength. Additionally, this study investigated the formation and characterization of biofilms on MP fragments under simulated marine conditions over a 305-day period. FE-SEM analysis revealed distinct morphologies of biofilm development and Crystal Violet staining quantified the biofilm biomass on the aged PE, PP, N6 pellets. Confocal microscopic analyses using Hoechst-33342 and AO/PI staining further elucidated biofilm composition, highlighting varied microbial densities and cell viability on MP surfaces. These observations contribute to the understanding of the complex processes governing microplastic degradation and emphasize the importance of considering environmental factors in evaluating plastic pollution.