环境科学与生态学最新文献

Copper (Cu) and nickel (Ni) coexist widely in industrial and municipal wastewater, especially acid mine drainage (AMD). However, research concerning the toxic effects and ecological risks of combined Cu/Ni stress on microalgae is scant, and a systematic comparison of microalgal responses between single and co-exposure conditions has yet to be systematically conducted. An indigenous acid-tolerant AMD microalga, Trebouxiophyceae sp. MA-1, was isolated and examined for its Cu and Ni tolerance and removal in this study. The algal growth was inhibited more severely by Cu than Ni. Co-exposure caused significant growth inhibition of the microalga. Intracellular uptake dominated Cu bioaccumulation in MA-1, yet 20 mg/L Ni drastically raised surface-adsorbed Cu fractions from 1.1 % to 35.5 % (0.8 mg/L Cu) and 13.1 % to 52.7 % (1.5 mg/L Cu). Functional groups associated with extracellular proteins and polysaccharides provided abundant binding sites, and protein-like substances in extracellular polymeric substances (EPS) were actively involved in Cu complexation. Ni promoted Cu bioaccumulation and aggravated oxidative stress; MDA levels reached 2.45- and 2.41-fold of the control under 1.5 mg/L Cu combined with 2 and 20 mg/L Ni, respectively. To mitigate this stress, MA-1 upregulated the activities of superoxide dismutase (SOD) and catalase (CAT) for reactive oxygen species (ROS) scavenging, and simultaneously enhanced the activities of enzymes related to the nitrogen metabolism pathway to assist in detoxification processes. Taken together, this study systematically elucidated the Cu/Ni bioaccumulation characteristics and detoxification responses of the acid-tolerant microalga MA-1, and highlighted the importance of accounting for interactions of multiple metals when assessing the ecological risks of heavy metal combined pollution.

Understanding the adhesion, growth, and biofilm development of chlorine-resistant bacteria (CRB) on reverse osmosis (RO) membranes is important for elucidating the microscopic mechanisms of biofouling. This study employed a typical CRB strain to systematically investigate its growth and fouling behavior on RO membranes. Temporal variations in CRB distribution and morphology, together with quantitative permeate flux decline, were analyzed to establish direct links between microstructural evolution and fouling performance deterioration. Three distinct developmental stages were demonstrated: (I) an initial aggregation stage (0-6 h), wherein CRB cell density increased slightly yet fouling layer resistance (R_f) rose substantially due to aggregate formation; (II) a cell proliferation stage (6-24 h), characterized by concurrent increases in cell density and R_f as CRB rapidly expanded and occupied the membrane surface; and (III) a matrix compaction stage (24-48 h), during which intensive EPS secretion filled intercellular voids, densified the biofilm matrix, and drove a further increase in R_f. This study elucidates the temporal shifts in fouling mechanisms, from aggregate-dominated resistance, to cell proliferation-driven surface coverage, and finally to EPS-induced matrix compaction, thereby providing mechanistic insight into the microprocesses governing CRB fouling on RO membrane.

Pregnancy is a vulnerable window for environmental pollutant exposure, yet the contribution of metals and metalloids (metal(loid)s) to gestational diabetes mellitus (GDM) remains insufficiently characterized. This prospective cohort study evaluated whether early-pregnancy urinary metal(loid)s were associated with subsequent GDM and explored their predictive and mechanistic value. Among 1201 pregnant women included in Guilin, China, nine urinary metal(loid)s were measured by inductively coupled plasma mass spectrometry. GDM was diagnosed by a 75-g oral glucose tolerance test at 24-28 gestational weeks. Restricted cubic spline and weighted quantile sum regression assessed dose-response and mixture effects. Machine learning models evaluated early prediction, and network toxicology explored molecular pathways. GDM occurred in 312 participants. Cadmium, arsenic, manganese, thallium, and lead showed nonlinear associations with GDM risk. Cadmium and arsenic dominated the overall mixture effect. Adding urinary metal(loid)s to conventional biochemical indicators modestly improved discrimination, with the XGBoost performing best. Network toxicology identified shared cadmium/arsenic targets enriched in oxidative stress, inflammation, apoptosis, endothelial dysfunction, and insulin-resistance pathways, including AGE-RAGE, HIF-1, TNF, and IL-17 signaling. These findings suggest that early-pregnancy metal(loid)s mixture exposure, particularly cadmium and arsenic, is associated with GDM risk, with arsenic the most consistent contributor across mixture methods and non-linear signals for lead and manganese warranting further investigation. Urinary metal(loid)s may serve as complementary biomarkers for early GDM risk stratification.

The widespread use of flumethrin has significantly jeopardized the survival of bees. However, the mechanisms by which bees and their intestinal microorganisms resist flumethrin remain to be elucidated. Therefore, this study aimed to explore the mechanism by which the gut microbiota of bees assist the bee host in resiling flumethrin stress. Bees were exposed to various concentrations of flumethrin (0.01, 0.1, and 1 mg/L) for 14 days, subsequently, performance parameters (body weight, gut weight, and food intake) and gut microbiota diversity and composition were assessed. Then, the performance parameters and mRNA expression of bees colonized by core gut bacteria (Bombilactobacillus mellis, Lactobacillus apis, Snodgrassella alvi, Bartonella apis, and Gilliamella apicola) and exposed to 1 mg/L flumethrin were evaluated. Chronic flumethrin exposure significantly reduced survival rate and gut weight, damaged intestinal structure, and induced gut microbiota dysbiosis in bees. However, gut colonization by B. mellis, S. alvi, and G. apicola significantly improved survival rate, body weight, and intestinal weight in bees. Importantly, G. apicola colonization significantly enhanced honeybees resilience to flumethrin, as evidenced by a significant increase in survival rate from 65.8 to 94.1% after G. apicola colonization. Moreover, bacterial gut colonization significantly upregulated the mRNA expression of immune detoxification genes, including superoxide dismutase, catalase, Toll, defensin-1, and abaecin, in bees. Collectively, these findings indicate that gut bacteria confer protection against flumethrin-induced stress by enhancing host immunity, underscoring the critical role of the gut microbiota in mediating honeybee resilience to environmental pollutants.

The article provides results of the study on retrospective evaluation of ¹⁴C pollution from Ignalina Nuclear Power Plant (INPP). Transfer factor approach was applied coupled with the radiocarbon measurements in Scots pine tree rings of extended network of 9 sampling sites around the INPP within the distance of 1.8 - 6.6 km from the INPP ventilation stacks. The measured ¹⁴C activity in tree rings suggested the annual airborne release estimate from the INPP to be in the range 0.43 - 11 TBq depending on the lifetime period of INPP which is in good agreement with other studies. The estimated average annual emission factor ranged from about 1 TBq/GWa in early operational years up to about 3 TBq/GWa after 10 years of operation. The most probable reason for this increase is the accumulation and aging of the graphite stack of INPP RBMK reactors. The last operational decade (1999 - 2009) is characterised by large fluctuations of releases which may be caused by the maintenance and waste management activities at INPP. The trend of last decade of our observations (2009 - 2019) is a continuous decrease of emissions up to 0.5 TBq per year after final shutdown of the reactors in 2009. The study shows high potential of accumulated ¹⁴C activity release due to dismantling and decontamination activities during the decommissioning phase of the NPP. The extended sampling site network effectively functioned as an aerial averaging system, reducing the influence of local peculiarities on sampling and modelling. As a result, the overall radiocarbon emissions reconstruction model uncertainty was estimated at approximately of 24%.

Hexavalent chromium (Cr(VI)) immobilization on iron oxides is commonly considered to rely on Fe(II)-mediated mineral transformation. Fulvic acid (FA) is ubiquitous in natural environments and interferes with interfacial reactions, yet its regulatory linkage between mineral evolution and Cr immobilization remains poorly understood. This study explored Fe(II)-mediated transformation of Cr(VI)-loaded lepidocrocite (LepCr) under anoxic conditions using batch experiments, spectroscopic characterization, and sequential extraction. Results confirmed that Cr(VI) was completely reduced to Cr(III) with no secondary release in all Fe(II)-amended systems. FA displayed a concentration-dependent effect on mineral conversion, which was partially decoupled from Cr immobilization. Lw FA (12 mg/L) facilitated lepidocrocite-to-goethite conversion via molecular bridging, whereas high FA (86 mg/L) significantly inhibited mineral recrystallization. Notably, as FA concentrations increased from 12 to 86 mg/L, the dominant Cr immobilization pathway shifted from mineral-transformation-associated processes to interfacial FA-Cr(III) complexation. Despite suppressed mineral transformation, high FA greatly elevated the proportion of non-extractable Cr from 25% to 54%, strengthening Cr immobilization. These results demonstrated that efficient Cr immobilization could be attained with reduced dependence on mineral transformation, where FA-Cr(III) complexation and Cr(III)-Fe(III) interfacial passivation dominated. Synchronous redistribution of FA at the solid-liquid interface further reinforced Cr sequestration. This work clarified the decoupled mechanism between mineral transformation and Cr immobilization, providing a mechanistic basis for optimizing Cr immobilization strategies in organic-rich contaminated environments.

Climate warming is expected to reshape sediment-associated metal behavior, yet whether warming responses of sediment metal(loid) lability are systematically regulated by baseline thermal conditions remains unresolved. Here, we combined diffusive gradients in thin films (DGT) measurements with controlled sediment incubations across 0-40 °C to quantify temperature-dependent lability responses of multiple metal(loid)s in coastal sediments. Distinct element-specific response regimes emerged. Redox-sensitive elements (Mn, V, and As) exhibited nonlinear increases in DGT-labile concentrations with warming, cobalt showed transitional non-monotonic behavior, whereas most particle-associated metal(loid)s displayed monotonic declines. These contrasting responses indicate that warming does not uniformly enhance sediment metal(loid) lability but reorganizes reactive metal behavior in patterns consistent with element-specific differences in solid-phase resupply and retention. Despite divergent element-specific trends, identical warming perturbations consistently induced larger relative lability changes at lower baseline temperatures. Model-based sensitivity analysis further showed that proportional warming responses were amplified under cold baseline conditions, identifying baseline temperature as a first-order regulator of sediment metal(loid) responsiveness to warming. This baseline-temperature control implies that climate warming may redistribute sediment contaminant sensitivity across thermal regimes, with cold coastal sediments exhibiting disproportionate geochemical responses. Our results provide a process-based framework linking warming, element-specific resupply kinetics, and sediment metal(loid) lability, and highlight baseline temperature as a critical but previously underrecognized control on contaminant dynamics at the sediment-water interface.

Introduction: Green space exposure during pregnancy and the early postnatal period is associated with lower autism spectrum disorder (ASD) risk. However, averaged exposure studies may miss time-specific sensitive windows spanning prenatal to early postnatal periods. Whether PM2.5 mediates or modifies this relationship remains unclear. This study aimed to identify critical windows of green space exposure and examine PM2.5's role.

Methods: A 1:3 matched case-control study was conducted, including 207 children with ASD and 621 healthy controls individually matched by age and sex. Participants were recruited from a tertiary maternal and child health hospital in central China. Monthly residential normalized difference vegetation index (NDVI), a satellite-derived metric of vegetation greenness, and fine particulate matter (PM2.5) levels from 10 months before to 3 months after birth were estimated for each participant based on maternal residential addresses. A distributed lag nonlinear model (DLNM) was used to quantify the association between monthly NDVI exposure and ASD risk and to detect critical windows for the protective effects of green space. Product terms were incorporated into conditional logistic regression models to test multiplicative interactions between NDVI and PM2.5. The bootstrap method was used to evaluate mediating effects, and Bonferroni correction was applied to account for multiple testing.

Results: Children with ASD had consistently lower monthly NDVI values than controls across all 14 months (from 10 months before birth to 3 months after birth; all FDR-adjusted P values < 0.01). A critical window was identified from 6 months to 1 month before birth (lags -6 to -1), during which higher NDVI was associated with lower odds of ASD. For this window, each interquartile range (IQR) increase in window-averaged NDVI was associated with a 46.6% reduction in the odds of ASD (OR = 0.534, 95% CI: 0.415-0.688). No significant multiplicative interaction between NDVI and PM2.5 was observed for any month (all P > 0.05 after correction), and mediation analyses revealed no evidence of mediation by PM2.5.

Conclusions: Green space exposure during mid-to-late pregnancy (corresponding to 6 to 1 month before birth for term births) is associated with substantially lower odds of ASD, independent of PM2.5. These findings suggest that prenatal care providers should consider advising pregnant women to increase green space contact during mid-to-late pregnancy. The identification of this temporally specific window also supports urban planning efforts to prioritize green space preservation in residential areas with high concentrations of pregnant women.

Microplastics are ubiquitous pollutants in freshwater ecosystems, yet their impacts on freshwater-sediment ecosystems remain poorly understood. Here, we investigated how pristine and mechanically weathered polystyrene (PS) microplastics influence organisms, sediment properties, and overall ecosystem multifunctionality (EMF) within an integrated freshwater-sediment microcosm containing the rooted macrophyte Vallisneria spiralis, the benthic snail Lymnaea stagnalis, and sediments. Results showed that mechanical weathering transformed the originally smooth spherical PS microplastics into particles with rougher and more irregular surfaces. Weathered PS microplastics induced stronger biological stress in both plants and snails, reflected in higher integrated biomarker response (IBR) scores. Weathered PS microplastics reduced chlorophyll a and carotenoid content and also altered plant nutrient content, indicating impaired photosynthesis and altered carbon metabolism. In snails, weathered PS microplastics triggered oxidative stress and significantly increased caspase-3 activity, suggesting elevated apoptotic responses and ionic regulation demands. Despite organism-level impairment, both pristine and weathered PS microplastics enhanced sediment EMF. This enhancement was primarily driven by increased dissolved organic carbon, elevated β-glucosidase activity, and intensified microbial respiration, reflecting stimulated carbon cycling. These results reveal an ecological trade-off between organism health and ecosystem performance. Short-term functional stability was maintained through accelerated microbial metabolism, potentially masking underlying biological deterioration. Our findings demonstrate that microplastic weathering amplifies biological stress while simultaneously promoting ecosystem-level functional buffering, highlighting that apparent stability may entail long-term ecological risk. Integrating environmentally representative mechanically weathered microplastics with multi-species ecosystem assessments provides a more comprehensive framework for evaluating the ecological risks of microplastic contamination.