Bulletin of Environmental Contamination and Toxicology最新文献

Pesticides pose a significant threat to soil ecosystems worldwide due to their widespread use in agricultural practices. Bioremediation offers a sustainable solution by leveraging the natural capabilities of microorganisms. This study explores the efficacy of Chlorella vulgaris in remediating dimethoate and atrazine contamination in soil environments. Culturing C. vulgaris in a pesticide-contaminated soil slurry revealed a dose-dependent increase in removal efficiency, peaking at a 1.0 mgL^-1 concentration for both pesticides. Moreover, contact time significantly influenced removal rates, with 40% dimethoate and 45.5% atrazine removal achieved after 14 days. Optimal microalgal dosage (10 mL) yielded the highest removal efficiencies, indicating a saturation effect beyond this threshold. High-performance liquid chromatography analysis confirmed notable reductions in pesticide concentrations post-bioremediation. Response Surface Methodology analyses further validated the model's significance and suitability for predicting removal efficiencies, highlighting the robustness of the bioremediation process. Findings underscore the potential of C. vulgaris as a cost-effective and environmentally friendly approach for mitigating pesticide contamination in agricultural soils. Future research should focus on elucidating the underlying mechanisms driving observed trends to further optimize bioremediation strategies.

Atmospheric transport and deposition of microplastics (MPs) represent an emerging pathway whereby plastic pollution reaches even the most remote ecosystems. To investigate how elevation influences this process, we collected rainfall and snowfall samples across eight sites in the Central Himalaya, India, at elevations from 445 m to 3,378 m. After multi-stage sieving (5 mm to 100 μm), oxidative digestion, and vacuum filtration onto 0.8 μm cellulose membranes, samples were analyzed for concentration, size distribution, and polymer composition. We observed an inverse relationship between altitude and MPs concentration, with urban low-elevation sites yielding up to 137 MPs L⁻¹ at 445 m, compared to only 5.5 MPs L⁻¹ at 3,378 m. Fibers dominated all samples (74.1%), reflecting textile sources, while films, fragments, cluster and foam composed the remainder. Particle size distributions shifted with height, larger MPs (1-5 mm) prevailed in low-lying areas, whereas fine particles (< 100 μm; 100 μm-1 mm) accounted for high-altitude and mid-altitude deposits, highlighting the role of small MPs in long-range atmospheric transport. Polymer composition also varied with elevation lightweight polymers like polyethylene (PE) and polypropylene (PP) became more common at higher sites, while heavier polymers such as polyvinyl chloride (PVC) & polytetrafluoroethylene (PTFE) remained concentrated at lower elevations. These findings suggest that altitude is a key control on atmospheric MP deposition low-altitude regions near dense urban sources exhibit higher concentrations, while remote high-altitude zones receive fewer but finer particles may be transported from urban area.

This study evaluates a novel mixed bacterial culture, comprising Acinetobacter baumannii IITG19, Klebsiella michiganensis RK, Providencia vermicola IITG20, and Pseudomonas aeruginosa IITG21, for its effectiveness in remediating diesel-contaminated soil and water. Through in-Lab degradation efficiency tests, simulated field studies, phytotoxicity tests, and degradation kinetics analysis, the potential of this culture was explored. During in-Lab study, the mixed culture showed 90% degradation of 4% v/v diesel over 15 days, at 35 °C temperature, pH 7, and 1% v/v inoculum concentration. Subsequent field studies showed diesel degradation of 96 and 99% in soil and water, respectively. The mixed culture showed 97% degradation of n-alkanes and branched alkanes and 96% degradation of naphthenes and aromatics in soil. In water, it showed over 99% degradation for all components. Phytotoxicity assessments with Brassica nigra seeds, ascertained successful growth in mixed culture-treated soil and water due to remediation. Degradation kinetics analysis confirmed first-order degradation, with a rate constant (k) of 0.144 day^-1 for in-Lab study. Field studies yielded values of 0.196 day^-1 for soil and 0.288 day^-1 for water. These findings showed that the mixed bacterial culture in this study was not only able to remove diesel contamination from soil and water but also restored soil health for plant growth. Its efficient performance under field-like conditions established its real potential for use in large-scale environmental clean-up efforts.

We investigated the effects of settleable atmospheric particulate matter (SePM, 1 g L^-1, 96 h) on metal bioaccumulation and blood biomarkers of the estuarine fish Centropomus parallelus. After exposure, V, Cr, Ni, Cu, Mo, Ag, W, and Pb accumulated in erythrocytes, while V, Cr, Fe, Nb, Mo, and Pb were found in plasma. SePM increased erythrocyte nuclear abnormalities (89.9%) and micronuclei frequency (117.6%), while decreasing neutrophils (51.6%). The erythrocyte antioxidant system responded with higher CAT and SOD activity (18.4% and 54%) to mitigate biomolecular damage, yet lipoperoxidation (162%) and protein carbonylation (97.1%) persisted in erythrocytes, along with lipoperoxidation (91.3%) in plasma. Our findings demonstrate that SePM exposure alters antioxidant defenses and hematological responses. Observed mutagenic alterations indicate damage with potential ecological implications. Blood biomarkers thus represent sensitive, non-invasive tools for biomonitoring and early detection of stress in aquatic organisms exposed to SePM.

Sarus crane, Antigone antigone, is the tallest flying resident crane in India. As these birds use agricultural fields as foraging and nesting grounds, they are exposed to environmental contaminants from agricultural runoff. This study documents the presence of the residue of selected agrochemicals in the tissues of birds from electrocution. Vital tissues, including liver, muscle, kidney, brain, and gut content from 14 individuals, were analyzed to determine the presence of 67 pesticide residues using Gas Chromatography-Mass Spectrometry and Liquid Chromatography-Mass Spectrometry. Sixty-four percent of the birds that were tested had at least one pesticide residue. Out of 67 chemicals tested, residues of only 4 chemicals, namely Chlorpyrifos, Dichlorodiphenyltrichloroethane, Hexachlorocyclohexane, and Endosulfan, were at detectable levels. This study presents the first report on pesticide levels in A. antigone in Uttar Pradesh, India. Although the levels of pesticide detected were below the previously reported levels, the mortality due to pesticide poisoning and power lines across the entire distribution range of Sarus cranes in India remains a cause for concern.

Mussels have been widely used in ecotoxicological studies due to their filter-feeding activity and sessile lifestyle, which makes them a suitable bioindicator organism. Thus, freshwater mussels (Unio delicatus) were exposed to different concentrations (0, 0.5, 2.5, 12.5 mg/L) of ZnO nanoparticles (18 nm) for 14 days to investigate responses of biomarkers belonging to the antioxidant, osmoregulation and energy systems. Laboratory-cultured algae (Chlorella vulgaris) were served to mussels (approximately 250,000 algae/ml) during the experiments. Significant (p < 0.05) accumulation of Zn occurred only in the gills. Enzymes belonging to the gill osmoregulation system did not respond to ZnO NP exposures (p > 0.05). However, activities of antioxidant system enzymes were altered significantly (p < 0.05) in the digestive glands. Levels of glucose and lipid significantly (p < 0.05) decreased, resulting in a decrease in immediate energy reserves of mussels. Although ZnO nanoparticles exhibited low tissue accumulation, they affected the metabolic systems of U. delicatus, emphasising the potential effects of nanoparticles.

Microplastics can serve as sites for microbial attachment, however their role in facilitating biotoxin entry into marine food webs remains poorly understood. This study quantified the adsorption and desorption kinetics of brevetoxin 3 (PbTx-3), a neurotoxin produced by the dinoflagellate Karenia brevis, on polyethylene (PE) surfaces in relation to the presence of biofilms using radiolabeled ³H-PbTx-3. It was hypothesized that the presence of biofilms would enhance toxin retention on PE. Contrary to this hypothesis, results revealed significantly reduced adsorption of brevetoxin on biofilm-coated PE (0.035 ± 0.007 nmol mg^-1, p < 0.001) compared to virgin PE (0.59 ± 0.076 nmol mg^-1). Furthermore, toxin desorption from biofilm-coated PE occurred rapidly, with less than 20% activity remaining after 24 h, whereas virgin PE retained over 80% activity over the same period. Complete toxin depuration was not observed within one week under either condition. These findings demonstrate that biofilms not only reduce brevetoxin adsorption on PE but also accelerate desorption. Further research is needed to elucidate the broader ecological and health implications of microplastic-mediated biotoxin transport, albeit the results of this study suggest that biofilm-coated PE likely plays a minor role as vector for biotoxins in marine food webs, at least compared to its virgin counterpart.

Nitrogen dioxide (NO₂) in the air at concentrations exceeding permissible levels impacts environmental quality and human health. In addition, NO₂ is also a precursor to ozone and an agent that creates acid rain that affects the habitat of organisms. NO₂ emission inventories are the first and most important step, especially in urban or industrial production areas. This study assesses NO₂ emissions in Ho Chi Minh City (HCMC), Vietnam-a large city with high traffic and industrial activity but limited published emission data. Using the Lifetime-Modified Accumulation Method (LMAM), we analyze tropospheric NO₂ column data from the OMI/Aura satellite (2019-2024) to estimate spatial and temporal emission trends. The results showed an average emission rate of 6.56 × 10¹⁵ molecules cm⁻² h⁻¹ in 2019, decreasing to 5.79 × 10¹⁵ molecules cm⁻² h⁻¹ in 2020 due to the COVID-19 lockdown. Emissions were highest in urban and industrial areas and lowest in suburban areas. The LMAM model demonstrated a strong correlation with TROPESS Chemical Reanalysis (TCR) NO_x data (Spearman's r = 0.71 in 2019; r = 0.70 in 2020), confirming its reliability for trend analysis. Long-term trends reflect the socioeconomic impact: a sharp decline during the pandemic (2020-2021) followed by a recovery to 1.3 × 10¹⁶ molecules cm⁻² h⁻¹ in 2023-2024 when economic activities resume. This result can provide information on NO₂ emissions as a reference for future city emission control policies and inventory plans.

Arsenic (As) accumulation is a critical environmental concern in many developing countries due to its high toxicity and wide distribution. In the current investigation, As contents were estimated in soil, forage and cow's milk samples collected from rain-fed and groundwater-irrigated areas of Chakwal, Pakistan. The samples were subjected to wet digestion and examined for As contents using an atomic absorption spectrophotometer. As concentrations ranged from 2.28 to 10.57 mg kg^-1 in soil, 0.663 to 2.40 mg kg^-1 in forages, and 0.012 to 0.017 mg kg^-1 in milk. Among the forages Chenopodium album demonstrated the highest As contents at the groundwater-irrigated site, while Tribulus terresteris had the lowest As contents at the rain-fed site. All samples exhibited As levels below the permissible limits set by WHO. This study also found a significant positive correlation between As levels in soil and forages at both sites, while the correlation between forages and milk was negative and non-significant. All estimated pollution indices were below the threshold limit, indicating insignificant As contamination across study sites. However, Chenopodium album exhibited significantly higher pollution indices than other forage species (p < 0.05), signaling its enhanced bioconcentration potential.