The study examines the toxicity of cadmium (Cd), microplastics (MPs) and their combined pollution on wheat plants, focusing on Cd accumulation and alterations to soil physical and chemical properties. To provide guidance for understanding the physiological and ecological responses of wheat to Cd and MPs contamination. Using a soil pot experiment, the individual and combined impacts of Cd (0 mg kg(-)(1) and 5 mg kg(-)(1)) and polyvinyl chloride microplastics (PVC-MPs) (0%, 0.5%, 1.0%, and 5.0%) on various aspects of wheat growth were assessed. Partial least square (PLS) model was employed to analyze the quantitative relationship between wheat growth indicators and various physicochemical parameters. Results revealed that the PVC-MPs significantly suppressed wheat growth parameters, photosynthetic efficiency, and chlorophyll content. As the level of contamination increased, the damage to wheat chloroplasts became more severe, leaf thickness reduced, and canopy temperatures rose. Conversely, root morphology parameters and Cd accumulation in wheat plants exhibited a declining trend. Moreover, soil fertility indicators and the activities of soil urease, acid phosphatase and dehydrogenase increased in correlation with higher concentrations of PVC-MPs. The PLS model identified stomatal conductance as the critical controlling factor influencing wheat growth under the combined stress of PVC-MPs and Cd. Overall, co-occurring Cd and PVC-MPs can change wheat plant performance and soil traits. These findings provide crucial insights into the physiological and ecological impacts of Cd and microplastic co-pollution in wheat-soil systems.

The extreme conditions in arid ecosystems make these environments sensitive to environmental changes. Particularly, land use and seasonal changes are determinants of their soil carbon dynamics. The effect of those elements on soil respiration (RS) is still poorly known in several arid regions of the world. This study investigates the seasonal effect on the R(S )and its controlling factors throughout different land use systems in northeastern Mexico. RS and 34 biotic and abiotic variables were measured across agricultural crops, natural shrublands, livestock farms, walnut orchards, and industrially influenced soils during the dry and wet seasons. Six variables (soil water content, soil organic matter, soil temperature, silt, and pH) were found as drivers of R(S )on both local and regional scales. Seasonal and land use had a transversal effect on R-S and its controlling factors. R-S dynamics were primarily modulated by soil water content, with the wet season and managed lands showing increased sensitivity to climatic and anthropogenic changes. These results indicate that land management strategies are critical for carbon cycling, particularly in water-limited regions like northeastern Mexico, where land use changes are occurring at an accelerated pace.

Urban cover-collapse sinkholes pose a significant global challenge due to their destructive impacts. Previous studies have identified groundwater fluctuations, subsurface soil conditions, pipeline leakage, precipitation, and subterranean construction activities as key contributors to these phenomena. However, unique geological settings across different urban environments lead to variations in the primary factors influencing sinkhole formation. This study focuses on Shanghai, a city notable for its extensive urbanization and rich historical context, to explore the dynamics of sinkholes within urbanized areas worldwide. We employ spatial analysis and statistical methods to examine data on sinkholes recorded in the past two decades in Shanghai, correlating these events with the city's shallow sand layer, ground elevation, and proximity to surface water. Our goal is to identify the dominant factors governing sinkhole occurrence in Shanghai and to lay the groundwork for their effective scientific management and prevention. Key findings indicate that most sinkholes in the area are associated with a thin shallow sand layer, low to moderate ground elevations, and the absence of nearby rivers. Additionally, many sinkholes correlate with subterranean voids within the confined aquifer beneath the cohesive soil layer. The lack of historical river channels, obscured by urban development, also indirectly contributes to sinkhole formation. We recommend enhancing urban river management and drainage systems to mitigate potential damage from water accumulation.

PurposeWetlands have a critical impact on the global carbon cycle. This study aims to investigate the spatial and vertical distribution of the soil organic carbon concentration (SOCc), to identify the differences of SOCc among swamps, marshes, bogs, and fens at a regional scale, and finally to examine the main environmental factors impacting SOCc at different depth intervals within different wetland types located in the Greater Khingan Mountains (GKM).Materials and methodsA total of 218 soil samples were collected. SOCc was determined by the combustion-oxidation method. To analyze the impacts of wetland type, soil type, mean annual precipitation (MAP), mean annual temperature (MAT), evapotranspiration (ET), elevation (EL), and slope (SL) on SOCc, statistical analysis methods were executed, including ANOVA with the Duncan test, Pearson correlations analysis, and the stepwise multiple regressions analysis.Results and discussionThe mean values of SOCc in the 0-30, 30-60, and 60-100-cm intervals were 130.4, 64.2, and 32.6gkg(-1), respectively. The wetland type played an important role in the pattern of SOCc in terms of significant differences (p<0.05) among the different wetland types in the 0-60-cm depth. However, significant differences were not found among different soil types. In terms of the wetland type, the highest SOCc was found in bogs (p<0.05), probably due to the higher MAP and lower MAT. The increased MAP (R-2=0.1369, p<0.01) and decreased MAT (R-2=0.1225, p<0.01) had positive associations on the wetland SOCc. ET (R-2=0.2809, p<0.01), MAP (R-2=0.2025, p<0.01), and EL (R-2=0.0484, p<0.05) were positively correlated with marsh SOCc. Moreover, MAP was positively correlated with the bog SOCc (R-2=0.1296, p<0.01). For vertical patterns, SOCc was higher in the 0-30-cm interval and decreased with depth. The impacts of environmental factors on SOCc decreased with depth for each wetland type. Models were developed to document the relations between the SOCc of marshes and fens and corresponding environmental factors.ConclusionsWetland types largely differed in the soil carbon pools in the GKM of China. The relative importance of environmental factors was different for the SOCc values of various wetland types. To minimize carbon loss into the atmosphere, more protections are required for wetlands, especially in the 0-30-cm depth interval because it contains higher SOCc values and is more vulnerable and less stable than those in the deeper layers.