Bulletin of Environmental Contamination and Toxicology最新文献

Vetiveria zizanioides, as a perennial herb with high biomass, provides a feasible method for the phytoextraction of cadmium (Cd). In this study, two levels of Cd exposure (18 and 200 mg·kg^-1) were performed to investigate Cd accumulation in Vetiveria zizanioides. The results showed that Cd content in dead shoots reached 1412.35 mg·kg^-1, 5.79 folds higher than that in roots. Cd stress promoted Fe mobility in the soil and increased Fe accumulation in plant. The correlation between Fe and Cd revealed that the competition between Fe and Cd inhibited the metabolic absorption of Cd in Vetiveria zizanioides. Cd stress accelerated shoot senescence and increased stomatal density, suggesting that Cd flowed into dead shoots was mainly motivated through its vessel transport. This study offers a theoretical basis for phytoextraction of high Cd-contaminated soils.

The thyroid glands of an 11-year-old castrated cow housed in a region contaminated by the Fukushima Daiichi Nuclear Power Plant accident were collected for histopathological examination. The estimated cumulative external exposure dose was 459 mSv. Macroscopically, the left lobe of the thyroid gland was firm and enlarged, and multilobular cystic structures could be observed on the cut surface. Histologically, the tumor cells were tall, cuboidal to columnar, and formed follicles of variable sizes and shapes. The fibrous capsule was unclear, and the neoplastic invasion of follicular tumor cells was obvious in the adjacent thyroid parenchyma. Immunohistochemically, the tumor cells were positive for thyroglobulin and thyroid transcription factor-1, and the MIB-1 index was 6.2%. Based on these findings, the neoplastic lesion was diagnosed as thyroid carcinoma. This is the first report of thyroid carcinoma in a cow exposed to radiation caused by the Fukushima Daiichi Nuclear Power Plant accident.

High levels of Co(NO₃)₂ for living organisms are toxic. In this study, the protective effects of 2,6-dimethyl-morpholine dithiocarbamate (DMMDTC) against the toxicity of Co(NO₃)₂ on Allium cepa L. were investigated. Seven groups of onion bulbs were established to investigate the potential effects of DMMDTC against Co(NO₃)₂ exposure in root tips. These are a control group, two groups of DMMDTC alone in different concentrations, two groups of Co(NO₃)₂ in different concentrations, and finally, two groups of combined DMMDTC (1,2) + Co (1,2) in different concentrations were applied to onion roots. The effects of the chemicals on physiological parameters, Mitotic Index (MI), Micro Nucleus (MN), genotoxicity and Co(NO₃)₂ accumulation in the roots were examined. MI analysis revealed that Co(NO₃)₂ treatments reduced the MI compared to water control by 52.2-46.6%, depending on the concentration. The combinations of DMMDTC + Co(NO₃)₂ significantly increased MI while decreasing MN compared to the cobalt-only treatments. However the protective effect of DMMDTC against cobalt toxicity was limited when the data compared to the water control. The heavy damage to epidermis cells and nucleus was also observed in those cobalt applied groups. Co(NO₃)₂ accumulation in the roots, compared to water control, was also high in Co1-Co2 groups. The DMMDTC used in this study had effects similar to those of plant extracts in reducing genotoxic effects. Therefore, the research highlights the potential benefits of using synthesized DMMDTC on Allium cepa against the toxic effects of cobalt.

Understanding the role of chelating agents on Cd bioavailability is key for assessing risks and guiding remediation in Cd-contaminated soils. Effects of three common chelating agents on Cd availability to microorganisms and plants were investigated using solution with similar Cd species profiles. As indicated by a Cd-inducible Escherichia coli biosensor, citric acid, nitrilotriacetic acid, and N,N-bis(carboxymethyl)glutamic acid (GLDA) significantly enhanced microbial Cd availability, with fluorescence intensities adjusted to OD₆₀₀ increasing by 1.50-1.71, 1.78-1.87, and 1.69-2.10 times. But these agents caused comparable or diminished Cd accumulation in Sedum plumbizincicola, with GLDA causing a 67.7% decrease. Microorganisms with sulfhydryl-rich ligands effectively compete with chelating agents for Cd, unlike less competitive ligands of roots. Thus variations in Cd bioavailability stem from different biological ligands on biological surfaces and secreted by microorganisms and plants, affecting surface interactions and metal speciation. This highlights the role of biological ligands in determining Cd availability.

This study examines the prevalence, characteristics, and distribution of microplastics in the Gaula River, Uttarakhand, India. Microplastics collected from surface water samples at four upstream and four downstream locations along the Gaula River in Uttarakhand were analyzed using SEM-EDS and FTIR spectroscopy to assess their concentration and composition. A total of 212 microplastic particles were identified, with higher downstream accumulation (122 particles) than upstream (90 particles). Fibers and fragments were the dominant shapes, primarily composed of polyethylene (PE) and polypropylene (PP). FTIR confirmed polymer-specific functional groups, while SEM-EDS revealed smooth surfaces with minimal heavy metal adsorption, indicating recent contamination. Findings suggest improper waste disposal and urban runoff as primary pollution sources. This study enhances understanding of microplastic pollution in freshwater ecosystems, particularly in urbanized regions, and underscores the urgent need for effective monitoring and mitigation strategies to reduce environmental impacts.

Coastal lagoons, like lake Edku in north Egypt, are vital ecosystems that offer a wide variety of ecosystem services, including wildlife habitats. However, many are experiencing severe human impacts due to their proximity to urbanization. The main objectives of this study were to determine the concentrations of major and trace elements in lake Edku sediments, and to assess their ecological risk impacts based on Contamination Degree (Cd), Pollution Load Index (PLI), and Potential Ecological Risk Index (PERI). During March 2022, six sampling stations (S1 through S6) were established across the lake, and a total of 14 elements were analyzed using inductively coupled plasma optical emission spectroscopy (ICP-OES). Our analyses indicate that sediment collected from sampling stations near to sources of wastewater runoff is the most polluted. For example, S1, which is located near to wastewater discharge, had the highest concentration of Cr, Co, Ni, Cu, Zn, Cd, and Pb (90.9, 23.1, 58.7, 55.2, 81.4, 0.5, and 12.8 µg/g, respectively). Evaluating the sediment PERI revealed that sampling stations S1, S2, and S4 had moderate ecological risk (150 < average PERI < 300), indicating there is a negative environmental impact on the living organisms and water quality of lake Edku. Because lake Edku is important for biodiversity conservation, continuous monitoring of metal contamination should be a top priority, as well as improving the efficiency of wastewater treatment facilities to ensure removal of metals before discharging to coastal ecosystems.

Microplastics (MPs), notably polyvinyl chloride (PVC) and polypropylene (PP), are major pollutants in terrestrial and aquatic ecosystems. PVC and PP are the most used polymers for manufacturing plastic goods and therefore constitute bulk of plastic debris which are the major sources of MPs. This study examines the impact of PVC and PP MPs on soil total antioxidant capacity (TAC) and microbial exoenzyme activities. A 0.25% (w/w) MP addition significantly reduced soil TAC and the activities of amylase, invertase, and dehydrogenase over 72 h, while cellulase activity increased. The effects varied by MP type, with molecular docking revealing stronger MP binding affinities to exoenzymes for PP than PVC, particularly with cellulase. The findings indicate MPs reduce soil antioxidants and most exoenzyme activities, except for cellulase.

Despite the widespread presence of heavy metals (HMs) in contaminated soils, there is a limiting understanding of physiological and cellular adaptive mechanisms of castor bean (Ricinus communis L.) under lead (Pb) contaminated soils of Chakera having enduring history of wastewater irrigation. This gap in knowledge hinders the development of effective strategies for managing soil pollution and protecting agricultural productivity in areas exposed to wastewater irrigation. Therefore, current pot study was conducted on two castor bean genotypes (NIAB-2020 and DS-30) on Pb contaminated soils of Chakera in glasshouse for a period of 120 days. Results showed that physiological indicators decreased under stressed conditions in NIAB-2020 and DS-30, suggesting impaired plant development. Electrolyte leakage (EL) increased in stressed plants indicating damage to cell membrane due to oxidative damage. Biochemically, the levels of superoxide dismutase (SOD) and peroxidase (POD) decreased whereas catalase (CAT) and ascorbate peroxidase (APX) showed an increase in both castor bean genotypes to mitigate oxidative stress. In similar pattern, both genotypes exhibited a reduction in total soluble proteins (TSP) and total free amino acids (TFA), while conversely total soluble sugars (TSS) and total phenolic contents (TPC) increased under stress conditions. Significant correlation was observed between various physiological, biochemical, and antioxidant enzyme responses, indicating their role as stressed biomarkers on Pb contaminated soils. Overall, NIAB-2020 outperformed DS-30 in terms of physiological and biochemical adaptations, evidencing superior adaptive approach. However, future field trials are compulsory to validate the findings of the study.

Lead (Pb) pollution has always been a persistent and unresolved environmental issue of great concern. This study innovatively applied Pb isotopic compositions and inverse distance weighting (IDW) to quantitatively identify Pb source contributions in the soil-wheat system in Kaifeng, China. Results showed Pb concentrations followed as soil > root > stem > shell > grain, with 18.2% of grains exceeding the National food safety standard (0.2 mg kg⁻¹). Quantitative source identification displayed atmospheric deposition contributed 66.82%, 66.32% and 63.00% to grains, leaves and shells, respectively, while sewage irrigation accounted for 67.74%, 58.61% and 57.56% in roots, stems and soils. Lighter Pb isotopes from atmospheric deposition were more readily absorbed by leaves and enriched in grains, whereas roots and stems retained heavier isotopes from sewage irrigation, effectively blocking their migration to grains and reducing health risks. This study provides valuable insights into Pb uptake, migration, and mechanisms in the soil-wheat system. It is commended reasonable regulation of rhizosphere soil and atmospheric environment or physiological interference on wheat growth might be an effective way to reduce the risk of Pb enrichment in wheat grains.

Total petroleum hydrocarbons (TPH) are a kind of widely distributed pollutant, while its bioremediation in situ and how it is affected by microplastics (MPs) in soil remains unknown. A pot experiment was conducted to investigate the degradation capabilities of total petroleum hydrocarbons (TPH) by a novel petroleum hydrocarbon-degrading bacterium TDYN1 with different concentrations of microplastics PP and PE. The TDYN1 significantly enhanced TPH degradation rate at 42.4 ± 0.9%, compared to 12.1 ± 2.6% in the control. The microplastics affected the TPH degradation depended on their amount, and no difference in degradation rates between PP and PE. The 1% PP and PE facilitated the degradation of TPH, while the 4% PP and PE inhibited it after strain added. Strain TDYN1 increased the dehydrogenase, polyphenol oxidase and urease enzyme activities, and the number of TDYN1. After remediation, the pakchoi yield was increased by strain addition, but was reduced by PE, indicating a risk of TPH and PE combined pollution for vegetable growing. It helps to better understand the microbial remediation on TPH-microplastic compound-contaminated soil, and provide theoretical support for its evaluation of application.