Journal of hazardous materials最新文献

Soil heavy metal pollution poses a significant threat to soil biodiversity. While extensive research has examined heavy metal impacts on soil communities and organismal health, their effects on soil fauna gut microbiota remain less explored. Here, we characterize gut microbial communities of soil nematodes across heavy metal gradients using high-throughput sequencing. The gut microbiota of soil nematodes was predominantly composed of Proteobacteria (75.97 %), Firmicutes (6.62 %), Actinobacteriota (3.79 %), etc. Remarkably, core microbial taxa (shared ASVs) represented 89.77 % of total sequences, indicating high compositional similarity across nematodes. Heavy metal pollution significantly reduced gut microbiota diversity and compositional stability (p < 0.05). RDA analysis identified cadmium (Cd), copper (Cu), chromium (Cr), soil properties (TN, TP, TOC), and soil bacterial diversity as key determinants of community structure, with Cd emerging as the primary driver through Mantel tests and random forest analysis. A significant negative correlation existed between Cd levels and microbial diversity (p < 0.05). Structural equation model further delineated that Cd impacts nematode gut microbiota via both direct and indirect pathways mediated by soil properties and bacterial diversity. Network analysis demonstrated increasing complexity (interactions) and stability under pollution escalation, evidenced by rising network density (0.053→0.093→0.100) and declining modularity (0.579→0.480→0.464). Core microbiota in heavily polluted soils exhibited enhanced disturbance resistance, underscoring their role in maintaining stability under metal stress. Collectively, heavy metals drive a dual response: diminishing diversity and stability while simultaneously selecting for adaptive microbial network restructuring. This study elucidates the variations in nematode gut microbiota under heavy metal stress, advancing understanding over adaptive response of gut microbiota to contaminated environments.

Metamorphosis alters the concentration and composition of contaminants in insects; however, its effects on per- and polyfluoroalkyl substances (PFASs) are poorly understood. In this study, the bioaccumulation, bioamplification, and elimination behaviors of PFASs were compared between silkworms and locusts during metamorphosis (holometamorphosis vs paurometamorphosis). Perfluoroalkyl carboxylic acids and perfluoroheptane sulfonic acid (PFHpS) were the predominant PFASs in silkworm larvae, while PFHpS, perfluorooctane sulfonic acid (PFOS), and 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) were dominated in locust larvae. The concentration and uptake efficiency of ΣPFASs in silkworm larvae were higher than those in locust larvae (p < 0.05), indicating that silkworm has a stronger bioaccumulation potential than locust. This is mainly due to locust larvae excrete high levels of PFASs (41-51 %) through their feces and therefore absorb fewer PFASs. The bioamplification factors of most PFASs in male and female silkworm were lower than the predicted values, and exuviation (mainly E2 and E3) is an important pathway for the elimination of PFASs during holometamorphosis. The higher elimination efficiencies of PFOS, 6:2 Cl-PFESA, and sodium p-perfluorous nonenoxybenzenesulfonate were observed in silkworms, but some short-chain PFASs shown higher elimination efficiencies in locusts. Overall, the elimination efficiencies of ΣPFASs in silkworms (34-39 %) were significantly higher than those in locusts (7.6-11 %, p < 0.05) during metamorphosis. These results suggest that silkworms and locusts exhibit different coping strategies in response to PFAS pollution, due to their distinct metamorphic processes and physiological functions. Furthermore, the cocoon formation by silkworms and the emergence of locusts were both delayed by one or two days after PFAS exposure. The sex-specific, dose-dependent, and long-term toxic effects of PFASs on insects require attention.

The risks posed by potentially toxic elements (PTEs) in aquatic organisms have received great concern, yet little is known about the comparison of PTE trophodynamics between marine and freshwater food webs. In this study, we characterized the bioaccumulation and trophodynamics of 9 PTEs in the organisms from Liaodong Bay and Songhua River. High concentrations of Zn, Cr, Ni and Cu were found in the organisms from both the two waters. The capacity of freshwater organisms to accumulate Cd, Li and Pb was stronger than that of marine organisms, while marine organisms had a stronger ability to accumulate Cu, Hg and Ni than freshwater organisms. The biomagnification of Hg was observed in both marine and freshwater food webs. Cd, Pb, Cu and Li exhibited biodilution in both freshwater and marine food webs. As, Cd and Pb may pose a carcinogenic risk to both adults and children, especially in SHR. This study provides the first insights into the comparison of bioaccumulation and trophodynamics of toxic elements in marine and freshwater food webs. Future management measures should focus on monitoring the accumulation of PTEs in aquatic organisms to ensure that the risks associated with human consumption of aquatic products are controllable.

This study introduces a novel in situ remediation strategy for soils contaminated with dense non-aqueous phase liquids (DNAPLs), focusing on trichloroethylene (TCE), using solid-stabilized (Pickering) emulsions. Beyond mechanical displacement, these emulsions are engineered to capture TCE via compositional ripening-a spontaneous, entropically driven mass transfer process that occurs when oil phases with differing chemical compositions come into contact or are separated by a continuous aqueous phase enabling molecular diffusion. Silica-stabilized emulsions with adjustable rheological properties (oil volume fraction from 0.01 to 0.21) were formulated and injected in water-wet micromodels containing TCE at its residual saturation, revealing a unique dual mechanism for TCE removal: shear-driven penetration into the pore network followed by gradual uptake of TCE into the emulsion droplets. Droplets swelling and phase redistribution confirmed the occurrence of compositional ripening, resulting in continued reduction of residual TCE saturation, even under static conditions. The proof of concept was done in batch experiments by monitoring the droplet size distribution of mixtures of TCE and emulsion. Micromodel tests confirmed high efficiency, with near-complete capture of capillary-trapped TCE. This dual-action process, combining physical displacement of the TCE with delayed physico-chemical capture under no-flow conditions, makes compositional ripening with Pickering emulsions a promising soil remediation approach.

Given global concerns over antibiotic resistance genes (ARGs), constructed wetlands (CWs) have emerged as a cost-effective strategy to remove nitrogen (N) and mitigate ARG-related ecological risks. The occurrence and dissemination of ARGs are mainly driven by microorganisms. Although nitrogen transformation is a key process in CWs, the relationship between nitrogen-transforming bacteria (NTB) and ARG dynamics remains unclear. In this study, metagenomic and metatranscriptomic analyses were employed to comprehensively examine the associations between N transformation and the abundance, hosts, and ecological risks of ARGs in full-scale CWs. NTB, particularly dissimilatory nitrate reducers and bacteria involved in N organic degradation and synthesis, were identified as the primary hosts of ARGs. Furthermore, CWs substantially reduced ARG-related ecological risks, achieving decreases of 79.5 % in ARG expression, 94.9 % in mobile genetic elements, and 88.0 % in antibiotic-resistant pathogens, and identified NTB as key contributors to these risks. Both the decline in NTB abundance and adaptive fitness costs were identified as key mechanisms driving ARG reduction and mitigating ecological risk. This study highlights the critical role of N transformation in shaping ARG dynamics from a microbial perspective, providing a theoretical foundation for engineering practice in the co-control of ARGs and nitrogen removal in CWs.

With the growth of the selenium product market, the development and utilization of selenium resources have attracted widespread attention. Electroadsorption has emerged as an innovative method for adsorbing Se(IV) from saline systems. In this study, an electric potential was directly applied to the active material electrode to facilitate the adsorption and desorption of Se(IV) ions. Magnesium aluminum layered double hydroxide (LDH) is a cost-effective material with high selectivity and excellent adsorption performance. Herein, magnesium aluminum LDHs intercalated with SO₄^2- (MgAl-SO₄^2--LDHs) were synthesized via a hydrothermal reaction. The electrochemical and adsorption properties of MgAl-SO₄^2--LDHs were evaluated in a simulated brine containing 100 mg Se/L and natural selenium-containing brine from Daba Songnuo Salt Lake (Xinjiang, China).The results demonstrated that, compared with static adsorption, the Se(IV) adsorption capacity of MgAl-SO₄^2--LDHs increased by 60.82 % when a positive voltage of 1.0 V was applied. Furthermore, the MgAl-SO₄^2--LDHs electrode retained 93.51 % of its adsorption efficiency after five adsorption-desorption cycles. The adsorption mechanism of MgAl-SO₄^2--LDHs was analyzed using electrochemical measurements combined with characterization techniques including XRD, XPS, TGA, and FTIR. Theoretical calculation results revealed that a large number of Se(IV) adsorption sites within the interlayers of MgAl-SO₄^2--LDHs remain unutilized. It is anticipated that the Se(IV) adsorption capacity of MgAl-SO₄^2--LDHs can be further enhanced by adjusting their interlayer spacing.This study presents a novel method for the electrochemical adsorption of Se(IV) using magnesium aluminum LDH as an adsorbent and provides new insights into its underlying adsorption mechanism.

The recovery of soil health in multi-contaminated sites remains a critical environmental challenge due to the simultaneous presence of organic and inorganic pollutants. While laboratory-scale experiments provide promising insights, in-field long-term validation is essential to assess soil health recovery under real conditions. In this study, a previously optimized phytoremediation approach was applied in a multi-contaminated site to evaluate its effectiveness in reducing pollutant loads and restoring microbial communities. The design included three treated pilot areas and an untreated control. Metaproteomics analyzed microbial functional activity and taxonomic shifts, supported by a protein extraction protocol for complex matrix. Results showed a marked reduction of contaminants: the sum of polychlorinated biphenyls (PCBs) decreased from 8.35 to 7.68 mg/kg in the control after 5 years, while in treated pilots areas it dropped to 0.68 mg/kg. Among heavy metals, significant declines were observed when comparing the untreated bulk control (B1) with the pilot areas treated through the biotechnological phytoremediation approach, with average reductions of about 92 % for mercury, 70 % for cadmium, 56 % for zinc, and 61 % for lead. Metaproteomic analysis revealed a restored microbial metabolic profile in treated soils, with increased abundance of metabolic enzymes (e.g., GAPDH, isocitrate dehydrogenase), stress proteins (GroEL, HSP70), and biosynthetic enzymes for amino acid and nucleotide production. Microbial taxa enriched in treated areas included Pseudomonas knackmussii and Microbacterium hydrocarbonoxydans. Conversely, control soils showed stress-dominated proteomes with limited metabolic capacity. These findings support the efficacy of phytoremediation and demonstrate the power of metaproteomics in monitoring ecological recovery.

Heavy metal contamination, especially cadmium (Cd), in agricultural soils poses a severe threat to food security and sustainable agriculture. This study explores the spatial heterogeneity of Cd concentrations in soils across China and identifies the key influencing factors. We analyzed a dataset of 669 soil samples collected between 2010 and 2021 using GeoDetector and GeoTree models to examine spatial variations and the interactions among natural and anthropogenic drivers. Our results reveal substantial regional heterogeneity in the factors affecting Cd levels. Anthropogenic activities dominate Cd accumulation in North and Southwest China, while lithology and climatic interactions govern contamination in the Northeast and Central-South. Key nonlinear interactions between fertilizers, pesticides, and industrial emissions exacerbate the risks of Cd contamination. We propose region-specific mitigation strategies integrating soil lithology, agricultural practices, and industrial policies in accordance with Sustainable Development Goals (SDGs). This study advances the mechanistic understanding of Cd dynamics in heterogeneous environments and provides actionable frameworks for global agricultural sustainability.

Feroxyhyte is an Fe(III) oxyhydroxide mineral capable of immobilizing large amounts of Sb(V). However, the mechanisms governing the uptake of Sb(V) by feroxyhyte have not been systematically examined and are poorly understood. This study presents the first investigation of Sb(V) uptake by feroxyhyte through both sorption and coprecipitation processes across an environmentally-relevant range of Sb(V) loadings. Antimony K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy revealed that Sb(V) sorption and coprecipitation (at all loadings) involved the development of edge and corner sharing linkages between Sb^V(O,OH)₆ and multiple Fe^III(O,OH)₆ octahedra. The Sb K-edge EXAFS results indicate that Sb(V) coprecipitation involved incorporation into feroxyhyte's structure via heterovalent Sb(V)-for-Fe(III) substitution, while Sb(V) sorption likely involved occupancy of vacant octahedral sites in feroxyhyte's near-surface structure. As a result of these uptake mechanisms, both sorbed and coprecipitated Sb(V) displayed very strong resistance to desorption via ligand exchange when exposed to SO₄^2-- or PO₄^3--rich solutions (during a commonly-used sequential extraction scheme). Overall, these findings provide new insights into Sb(V) uptake by feroxyhyte and highlight the role that feroxyhyte can potentially play in treating Sb(V)-contaminated water or stabilizing Sb(V) in contaminated soil, sediment and geogenic waste.

In electrochemical oxidation (EO) wastewater treatment, the more recent 2.5D electrode system relying on appropriate amount of physically fixed micro/nano-scale particles on the main electrode surface offers several key advantages over conventional 2D/3D electrode system, such as prominent versatility and recyclability. However, the full potential of the 2.5D electrode system has not been released so far due to the insufficient utilization of the massive inner active sites. To overcome this challenge, in this study, a novel 2.5D electrode flow-through reactor coupling system (2.5D-FT system) was developed, which featured by a hierarchical porous electrode architecture (novel Sb-SnO₂ coated molecular sieve particles loaded on porous RuO₂-TiO₂ or Sb-SnO₂ main electrode) and a staggered-flow-enhanced mass-transfer paradigm, allowing pollutants to fully contact the numerous inner active sites. Results show that the molecular sieve based particles greatly increases the active sites and reduces the electrode impedance. Various model pollutants including acidic red G, bisphenol A, tetracycline, and ciprofloxacin could be degraded more efficiently (e.g., up to 100 % removal) by a single-pass EO process. The enhancement of radical pathway (•OH, •O₂^-) and non-radical pathway (¹O₂), as well as the direct electron transfer (DET) process originating from the hybrid composition and unique structure of the novel 2.5D-FT system, is confirmed by quenching experiment results and multiphysics simulation results. In addition, results of anti-inference and durability tests, energy consumption evaluation, real wastewater treatment and toxicity assessment demonstrate the competitive practicability of the novel 2.5D-FT system.