Microbes play a significant role in the biogeochemical cycling of soil phosphorus (P). However, little is known on how P accumulation affects the microbial-driving regulation of soil P forms. This study investigated soil P forms and microbial community structure in the presence or absence of P accumulation using 31P-NMR spectroscopy and 16S rRNA high-throughput sequencing, respectively. Long-term P accumulation increased available P and orthophosphate, but decreased the proportion of phosphate monoester, phospholipids, DNA-P and pyrophosphate. Meanwhile, the abundant and rare microbial taxa possessed different response to soil P accumulation. As a result, due to the change in soil properties and different sensitivity to soil P content, P accumulation enhanced the alpha diversity indices of microbial community and reduced the relative abundances of Proteobacteria and Actinobacteria. In addition, Bacteroidetes, Firmicutes, Gemmatimonadetes, and Nitrospirae were positively correlated with orthophosphate, but negatively correlated with the P forms of phosphate monoesters, DNA, phospholipids, pyrophosphate, and the abundance of pqqC gene. Among the investigated soil properties, soil organic matter, pH, organic phosphate, and pqqC may dominate the assembly of microbial networks. Under P accumulation, rare microbial taxa may play a more important role in the assemble of microbial networks for soil P cycling than the abundant microbes. These findings may help to optimize soil management for an enhancement of P use efficiency.

Cadmium (Cd) is a major heavy metal contaminant in sediments in China; however, the aging and Cd immobilization mechanisms of non-metallic adsorbents in complex water-sediment systems remain unclear. Herein, the remediation effectiveness of biochar (BC), activated carbon (AC), and kaolinite (KL) on Cd-contaminated sediments was investigated, analyzing their effects on physicochemical factors, nutrients, Cd concentration, Cd speciation, and Cd toxicity. BC had the most significant impact on system pH and oxidation-reduction potential (ORP) during the initial 15 days, whereas AC exhibited the strongest ORP enhancement after 60 days. All three materials effectively mitigated the release of total organic carbon, total nitrogen, and total phosphorus. Cd release into overlying water was most inhibited by AC, followed by BC and KL. BC promoted Cd2 + deposition in the form of Cd3(PO4)2 on BC surfaces, significantly increasing the proportion of stable Cd. The surface functional groups of all materials degraded in the water-sediment systems. AC and KL aged after 60 days, whereas BC began aging around 30 days, owing to the preferential oxidative degradation of its organic macromolecular structures. This study provides technical support for sediment remediation and establishes an evidence-based foundation for low-cost material applications in pollution control engineering.

Mitigating eutrophication in shallow lakes necessitates accurate measurement of internal phosphorus loading—a task complicated by intricate sediment–water interactions and insufficient long-term monitoring. This study integrates high-resolution porewater monitoring with machine learning (ML) to quantify internal soluble reactive phosphorus (SRP) release in the large eutrophic Lake Taihu, China. Monitoring across the whole of Taihu Lake throughout 2021–2022 indicated that SRP release fluxes varied from −0.32 to 1.84 mg/(m2·day), with peaks occurring in summer–autumn within algal-dominated zones, where internal SRP release was closely associated with the reductive dissolution of Fe-oxides. Building on these observations, an ML approach using an optimized Ridge model predicted SRP release fluxes over the past two decades. The results showed that internal SRP release contributed an average of 45 % of total phosphorus (TP) increases during critical bloom periods. Structural equation modeling indicated that chlorophyll-a variability was strongly linked to internal SRP release, temperature, and TP, which together accounted for 65 % of the variation, suggesting internal SRP release is a key driver for sustaining algal blooms. Furthermore, two-decade dynamics of internal SRP release revealed that its predominant control factors are shifting from past anthropogenic disturbance pressures to climate-induced processes. The findings highlight the important role of internal SRP release in sustaining eutrophication, and provide scientific guidance for formulating adaptive remediation measures to control its release.

The formation of submerged areas in Qinghai Lake, driven by rising water levels, has resulted in substantial changes in environmental characteristics, phosphorus dynamics, and microbial community composition. Climate-driven hydrological expansion promotes phosphorus remobilization in submerged sediments, necessitating targeted management to mitigate eutrophication risks in Qinghai Lake and analogous alpine ecosystems. This study examines the impacts of submersion on water chemistry, sediment properties, and microbial communities across multiple sites around the lake, including submerged regions, estuaries, and the lake body. Water quality analysis revealed that eutrophication and pollution were more pronounced in flooded areas compared to the lake and estuarine zones, with particulate matter and chlorophyll significantly increased. pH and redox potential measurements revealed that submerged areas exhibited similar characteristics to the lake, with elevated pH and distinct redox shifts. Sediment analysis demonstrated significant changes in particle composition, with coarse sands larger than 0.63 mm accounting for most of the sediment in submerged zones, whereas finer particles (<0.16 mm) predominated in the lake and estuarine sediments, reflecting alterations in sediment texture due to flooding. Phosphorus concentration in water bodies was significantly elevated in submerged areas, with higher levels of both total phosphorus and inorganic phosphorus forms compared to the lake. Moreover, microbial diversity analysis indicated that microbial communities in submerged areas exhibited distinct characteristics from those in the lake and estuary, with greater complexity in co-occurrence networks and shifts in dominant microbial taxa, notably Rhodobacteraceae and Pseudomonadaceae. The abundance of phosphorus-related genes, particularly those involved in phosphate metabolism, was higher in submerged areas, indicating an enhanced microbial contribution to phosphorus cycling. These findings suggest that newly submerged zones not only accelerate internal phosphorus loading but also restructure microbial networks, thereby enhancing the risk of eutrophication. It emphasized shifts in nutrient cycling and microbial dynamics that may affect the overall health and stability of the aquatic ecosystem.

Harmful algal blooms (HABs) threaten lake ecosystems globally, requiring assessment tools that identify environmental controls and prioritize interventions. Traditional Habitat Suitability Index (HSI) models rely on fixed expert-based thresholds and lack diagnostic capabilities, limiting decision-support utility. We developed the Tolerance-Driven Aquatic Habitat Model (TDAHM) to address these limitations through two innovations: (1) monthly-varying thresholds calibrated against satellite-observed distributions via differential evolution, establishing empirical HSI-biomass relationships, and (2) dual diagnostics identifying limiting factors and management priorities. Applied to Taihu Lake, China (2016-2018) using 19 monitoring stations and MODIS imagery, TDAHM achieved validation correlation r = 0.70 (50% error reduction) against satellite-derived bloom areas, with monthly thresholds ranging 0.72-0.91. Limiting factor analysis identified NH3-N (49.4%) and DO (18.7%) as dominant bottlenecks following Liebig's Law, while management priority analysis revealed TP (39.7%), WT (32.0%), and TN (21.7%) as primary contributors based on weighted HSI contributions. This discrepancy provides complementary management perspectives: limiting factors identify acute local bottlenecks, while management priorities highlight strategic targets for lake-wide improvement. TDAHM transforms HSI from descriptive mapping to quantitative decision support, providing factor-specific targets using typical monitoring infrastructure. The framework balances traditional HSI simplicity with diagnostic capabilities unavailable in conventional approaches, offering operationally feasible guidance for lake management programs globally.

Algal blooms have happened frequently in Lake Hulun, China, regardless of reduction of external loading in the last 10 years. It may be due to the release of nitrogen (N) and phosphorus (P) in the sediment. In order to reveal internal loading, the diffusive gradients in thin films (DGT) technique is applied for measurement of inorganic phosphorus (PO4-P), iron (Fe), ammonium (NH4-N), and nitrate (NO3-N) at the sediment/water interface (SWI). P release from Fe-bound P in anoxic sediment is identified by the moderate or strong linear correlation relationship (0.69 <= R-2 <= 0.84; p < 0.01) between DGT-measured concentration, C-DGT(PO4-P) and (i) C-DGT(Fe), (ii) iron associated P (BD-P) or NH4Cl extractable P (NH4Cl-P) + BD-P, or (iii) Fe content in BD-P. The exchangeable NH4-N (NH(4)ex) and NO3-N (NO(3)ex) can act as release sources based on strong linear correlation of C-DGT(NH4-N) against NH(4)ex (0.70 <= R-2 <= 0.84; p < 0.01) or C-DGT(NO3-N) against NO(3)ex (0.68 <= R-2 <= 0.81; p < 0.01). NH4-N release is enhanced by organic matter (OM) on the basis of strong multivariable regression relationship (0.74 <= R-2 <= 0.91; p <= 0.001) of C-DGT(NH4-N) against NH(4)ex and OM. The opposite characteristics of "slow" and "fast" resupplies of PO4-P are derived by the DGT-induced fluxes in sediments (DIFS) model. The diffusive fluxes at the SWI are 50.3-460.5 & micro;g m(-2) d(-1) (PO4-P), -857.0-86.7 & micro;g m(-2) d(-1) (NH4-N), and -1267.2-290.6 & micro;g m(-2) d(-1) (NO3-N), and lake management should be conducted in some areas with the positive diffusive fluxes. DGT is a valuable method for the identification of the lake area with sediment internal loading, dredging depth in sediment, and immobilization efficiency for controlling the release of nutrients using the in-situ capping method.

Rice (Oryza sativa L.) readily accumulates cadmium (Cd), posing dietary exposure risks in populations dependent on rice-based diets. This study investigated how sulfur (S) redox processes regulate Cd mobility in S-deficient, Cd-contaminated paddy soil under waterlogged conditions. A pot experiment was conducted with two S treatments (-S and +S, 30 mg kg-1) throughout the rice growing season. S addition markedly increased pore water S2- concentrations during early growth (tillering) and mid-season (booting) and suppressed the diffusion of SO42- from non-rhizosphere to rhizosphere at later stages (filling-maturity). Consequently, Cd in soil pore water was significantly lower in +S than -S treatments at all stages. Sulfur-amended soil showed a redistribution of Cd from labile fractions (exchangeable and carbonate-bound) to more stable fractions (Fe/Mn oxide-bound). Sulfur application also altered the rhizosphere microbiome: the relative abundance of sulfate-reducing bacteria (SRB) increased at the booting and filling stages, while sulfur-oxidizing bacteria (SOB) became more dominant at maturity. Additionally, +S enhanced Cd sequestration on rice root iron plaque by 32-67% during the grain-filling and maturity stages compared to -S. Throughout the rice growing period, redox-driven shifts in the S2-/SO42- ratio emerged as a key control on Cd behavior, with low pe + pH (strongly reducing conditions) promoting Cd sulfide precipitation and high pe + pH (more oxidizing conditions) causing Cd remobilization.

Surface water quality in China has improved substantially over the past decade but has plateaued recently under current levels of industrial activity and nutrient (N, P, and chemical oxygen demand) discharge standards. This stagnation signals the need to identify previously underestimated drivers and actionable thresholds for achieving Sustainable Development Goal (SDG) 6.3 (clean water and sanitation). A high-resolution national water quality dataset was analyzed in this study using the random forest method, partial dependence analysis, and a modified coupling coordination degree model. Results revealed that groundwater extraction and petroleum pollution now surpass conventional nutrients in water-scarce regions and industrial clusters. The three dominant factors are per capita water resources, petroleum discharge, and groundwater usage, with thresholds for good water quality at 985 m3 per person per year, 108 tons per year, and 25.5 × 108 m3 per year, respectively; falling below these thresholds reduces water quality by 5–10%. The COVID-19 pandemic period highlighted reduction of petroleum pollutants as a key factor associated with water quality recovery. Based on these findings, a spatially differentiated management paradigm was proposed that prioritizes groundwater restoration in arid northern China, stringent petroleum control in coastal industrial clusters, and integrated water–agriculture measures in northeastern farmlands. This threshold-based, mechanism-explicit framework offers a pathway toward realizing SDGs in China, and provides a transferable methodology for other countries addressing the water–development–pollution nexus.

Heavy-metal research has long been guided by frameworks that emphasize dissolved and free-ion forms in explaining transport, reactivity, and toxicity. Yet metals in natural waters rarely occur only as isolated ions; instead, they are distributed across dynamic assemblages that include colloidal, organically complexed, nanoparticulate, particulate, and sediment-coupled forms interacting with dissolved organic matter, mineral surfaces, and co-occurring contaminants. These multicomponent forms can exhibit chemical behavior, bioavailability, and toxicity that differ from those predicted from ionic species alone. Here, we synthesize advances in nanoscale analytics, speciation-resolved measurements, and mixture toxicology to advance a more integrated framework that builds on established bioavailability concepts while incorporating kinetic behavior, multiphase partitioning, sediment-water exchange, and operationally defined fractions under environmentally variable conditions. We highlight examples involving metal-DOM interactions, particle-associated forms and hybrid contaminant systems, discuss implications for monitoring and risk assessment, and outline future directions linking mixture-aware modeling, colloid chemistry, and ecotoxicology. Framing heavy metals as dynamic nano-assemblages and chemical mixtures provides a more realistic basis for environmental monitoring, regulatory interpretation, and aquatic risk assessment.

The upper Yangtze River is an important water conservation area， and its hilly terrain is prone to soil erosion， which causes pollutants such as heavy metals to migrate into the water and then accumulate in the reservoir sediments. It may pose a potential threat to drinking water safety and water ecological health. In this study， the Quanmin Reservoir Basin of Sichuan Province located in the upper reaches of the Yangtze River was selected， and the basic sediment physicochemical properties as well as the spatial distributions and occurrence characteristics of heavy metals （including Cr， Mn， Ni， Cu， Zn， Cd， and Pb） in the main inflowing rivers and reservoir areas were investigated. The sources， correlations with environmental factors， and potential risks of heavy metals were analyzed using multivariate statistical methods. The results showed that： ① The average content of each heavy metal in sediments was higher in the downstream reservoir than that in the upstream rivers. Both in the river and the reservoir sediments， Mn and Cd mainly existed in the acid-soluble state in both the river and the reservoir， while the other five heavy metals mainly existed in the residual state. ② Combined with the results of the correlation analysis， principal component analysis， and the positive matrix factorization， the natural sources of Cr， Ni， Cu， Zn， Cd， and Pb contrabuted more than 60%， while the agricultural sources of Mn contrabuted more than 70%. ③ Organic matter， nitrogen， phosphorus， and redox potential in the sediments significantly affected the distribution and occurrence fractions of the studied heavy metals. ④ The pollution degrees and comprehensive potential ecological risks of heavy metals in the sediments were at the low level， but the average risk coding indexes of Mn and Cd reached 56.0% and 51.2%， respectively. Considering the different sources and the higher release potential of Mn when compared with those of the other metals， further attention should be paid to the potential impacts of Mn on the water environment and aquatic ecosystem.

Micro(nano)plastics (MNPs) in drinking water are an emerging global concern, with particular relevance for lowand middle-income regions where advanced purification technologies are not widely accessible. Recent work suggests that household boiling can reduce MNP concentrations through co-precipitation with calcium carbonate (CaCO3) incrustants, raising interest in boiling as a simple and potentially accessible intervention. However, the mechanistic basis, post-boiling stability of the resulting complexes, associated chemical interactions, and broader safety implications of this practice remain insufficiently resolved. This Perspective delineates five priority knowledge gaps that constrain evidence-based evaluation of boiling as an MNP mitigation strategy: (i) the posttreatment stability of MNP-CaCO3 complexes during storage and consumption; (ii) polymer- and particle-specific variability in co-precipitation efficiency across environmentally relevant MNP types; (iii) the currently unquantified behavior of sorbed contaminant "cocktails" under boiling-relevant conditions; (iv) modulation of boiling efficacy by freshwater salinization and broader water-chemistry controls; and (v) the still unresolved possibility of oligomer and monomer release under household-relevant heating conditions, together with limited regulatory clarity surrounding these compounds in drinking water. Collectively, these uncertainties indicate that the apparent particulate-removal benefit of boiling may be strongly conditional on water chemistry, particle properties, and post-boiling handling conditions. As boiling is increasingly discussed as a household response to MNP contamination, interdisciplinary evidence spanning water chemistry, materials science, toxicology, and exposure assessment is needed to define its boundary conditions, limitations, and public-health relevance. Robust validation under realistic water matrices and use scenarios is essential before boiling is incorporated into publichealth guidance or presented as a broadly reliable water-management strategy.

Heavy metals have long been a significant and challenging topic in the research and treatment of lake water environments due to their non-degradability and ease of bioaccumulation. With the advancement of industries such as manufacturing, agriculture, and heavy industry, coupled with the increasing demand for heavy metals, the levels of heavy metals entering the environment have been rising annually. This trend necessitates more refined control measures for heavy metals in the environment. Currently, research on heavy metals in lake sediments in China mainly focuses on spatial distribution, morphological analysis, and ecological risk assessment. However, the characteristics of heavy metal migration, transformation, and biological effects are still largely unquantifiable. This article analyzes soil pollution cases in multiple regions of China and summarizes the nine main sources of heavy metals in the environment. It discusses the characteristics and biological effects of heavy metal migration and transformation. Finally, from the perspective of human health risk assessment, it explores the future development direction of heavy metal research.

Biochar's performance to immobilize cadmium (Cd) in contaminated sediments easily fluctuates with environmental characteristics, yet systematic research on its adaptability is limited. This study comprehensively evaluated the impact of physicochemical properties induced by natural and anthropogenic fluctuations, such as pH, gravel size, dissolved oxygen, organic matter (OM), and phosphates, on the performance of biochar (BC300, BC500, NBC300) in Cd remediation. Cd concentrations in overlying and pore water, leaching levels, and sediment fractions (acidic soluble (F1), reducible (F2), oxidizable (F3), and residual (F4)) were analyzed to assess immobilization. The sensibility to environmental disturbances were examined using correlation and principal component analysis. Some scenarios slightly promoted Cd leaching into aqueous in the micrograms per liter (mu g/ L) range, with the highest concentration of 52.55 mu g/L in the NBC300-60 mesh gravel treatment. Gravel size significantly influenced Cd fraction transformation, while OP(OR)3 had the least effect. Sand negatively impacted Cd immobilization by increasing F1 and F2 after biochar amendment, though 80-mesh sand enhanced BC500 performance (40 % F4). Alkaline treatment led to effective biochar immobilization of labile Cd into residual form and reduced free and leached content, with highest 35 % F4 at pH 8.0 for NBC300. Conversely, aeration activated Cd, reducing F4 to 6 % in NBC300. OM effects varied, with 4 % fulvic acid (FA) notably enhancing NBC300's immobilization (17 % F4 in BC500). Among phosphates, Ca3(PO4)2 strongly promoted the conversion of labile Cd to residual form, while OP(OR)3 and Na3PO4 had minimal impacts. These findings highlight the importance of environmental conditions in optimizing biochar for Cd remediation.

With increasingly significant climate change trends in the next three decades, the ecological security of lake basins is of great significance to the sustainability of biospheres and human societies, and it is requisite to quantify their evolution in the future to evaluate possible impacts and risks. Here, we propose a measurement framework for the response of specific regions to climate change, and make predictions for the future situation of the Qinghai Lake basin, which plays a significant ecological role in northwestern China under three RCP (Representative Concentration Pathways) scenarios by means of machine learning model prediction, geographical identification and experimental simulation. Unlike studies that focus on isolated aspects such as historical data analysis or simple predictions, this framework provides a more comprehensive and dynamic analysis of the entire chain of causes and effects underlying a specific region's response to climate change, enhancing the overall understanding of this process. Our results show that under the predicted scenarios, water level changes in Qinghai Lake over the next 30 years may lead to land cover changes affecting nearly 200 km(2), with the largest exposure of underwater land (similar to 163.79 km(2)) occurring under the RCP 4.5 scenario, predominantly meadows and deserts. Nutrient fluxes into the lake are highest under the RCP 4.5 scenario, with up to similar to 4,141 tons of total nitrogen (TN) and similar to 276 tons of total phosphorus (TP) expected by 2050, posing risks such as lakeside ecological transformation, water pollution, and eutrophication. The significant influx of nutrients highlights that preventive strategies are necessary to mitigate potential threats and ensuring ecological security and sustainable development for the Qinghai Lake basin and similar sensitive lake systems.

Addressing the nitrogen geochemical cycle, accompanied with hydrological processes, influenced by anthropogenic nitrogen inputs provides new insights on policymaking for water resource management and aquatic ecosystems protection. However, there is currently a lack of further understanding on the source contributions of nitrate (NO3-) and transformations under explicit hydrological conditions. Due to their spatiotemporal heterogeneity, the impact of seasonal human activity changes on them has not been thoroughly elucidated. This study combines hydrogeochemical analysis, multiple stable isotopes (delta 15N-NO3-, delta 18O-NO3-, delta 2H-H2O, and delta 18O-H2O), statistical methods, and a Bayesian isotope mixing model (MixSIAR) to investigate surface water-groundwater interactions, nitrate sources and cycling processes in a hilly region of China. Results showed that groundwater hydrochemical types, governed by water-rock interactions and anthropogenic activities, shift seasonally, from HCO3-Ca & sdot;Mg in the dry season to Cl & sdot;SO4-Ca & sdot;Mg in the wet season, particularly in areas with high nitrate concentrations. Chemical weathering in groundwater was driven by the combined dissolution of silicate and carbonate rocks. Groundwater contributed 73.5 % to surface water, with the rate of 0.20 mm/day in March. Total interflow was 407.03 mm from May to October. Nitrification emerged as the dominant nitrogen transformation process in groundwater, while denitrification was localized, primarily occurring during the wet season. The major sources of NO3- in groundwater were soil nitrogen (SN; 48.4 f 17.5 % in the dry season and 30.5 f 11.6 % in the wet season) and manure and sewage (M & S; 41.0 f 17.7 % in the dry season and 54.8 f 11.7 % in the wet season). The spatial distribution of M&S contributions corresponded to elevated Cl-and SO42-concentrations, particularly at sites with high nitrate levels during the wet season. These findings reveal that anthropogenic nitrogen inputs significantly influence the spatiotemporal variability of groundwater hydrochemical types, nitrate sources, and nitrogen transformation processes.

Lake Baiyangdian is one of China's largest macrophyte - derived lakes, facing severe challenges related to water quality maintenance and eutrophication prevention. Dissolved organic matter (DOM) was a huge carbon pool and its abundance, property, and transformation played important roles in the biogeochemical cycle and energy flow in lake ecosystems. In this study, Lake Baiyangdian was divided into four distinct areas: Unartificial Area (UA), Village Area (VA), Tourism Area (TA), and Breeding Area (BA). We examined the diversity of DOM properties and sources across these functional areas. Our findings reveal that DOM in this lake is predominantly composed of protein - like substances, as determined by excitation - emission matrix and parallel factor analysis (EEM - PARAFAC). Notably, the exogenous tyrosine-like component C1 showed a stronger presence in VA and BA compared to UA and TA. Ultrahigh - resolution mass spectrometry (FT - ICR MS) unveiled a similar DOM molecular composition pattern across different functional areas due to the high relative abundances of lignan compounds, suggesting that macrophytes significantly influence the material structure of DOM. DOM properties exhibited specific associations with water quality indicators in various functional areas, as indicated by the Mantel test. The connections between DOM properties and NO3N and NH3N were more pronounced in VA and BA than in UA and TA. Our results underscore the viability of using DOM as an indicator for more precise and scientific water quality management.

Liquid crystal monomers (LCMs) are emerging pollutants that have attracted attention recently due to their unique chemical properties and wide applications. However, in-depth research on LCMs' potential risks to soil health remains blank. Therefore, 107 LCMs and nine soil health characterization proteins/enzymes were selected as research objects in this study. A grading evaluation system for soil health toxicological effect indicators under LCMs exposure was constructed from five dimensions (i.e., soil animals, soil plants, soil microorganisms, soil carbon, nitrogen and phosphorus cycles, and human health) by molecular docking and molecular dynamics simulation methods. Priority control lists for soil health toxicological effects under LCMs exposure were developed based on the proposed evaluation system, with rationality verified through non-bonded interaction, 2DQSAR and Meta-analysis. Results showed that 32, 56 and 19 LCMs presented unacceptable, potential, and acceptable soil health risks, respectively. The oxidative damage of LCMs to plant leaves, the toxicity to earthworm growth and development, and its effects on key enzymes of the soil nitrogen cycle were suggested to be the priority-attention indicators. This is the first study that provides theoretical support for revealing the toxicological effects of LCM exposure on soil health and relevant pollution control strategies.

The study of land use and land cover change (LULCC) in the Qinghai Tibet Plateau is an important part of regional land science and global change science research. Due to their sensitive response to climate change, plateau lakes undergo changes in their surrounding land use types and soil physicochemical properties, which in turn affect soil environmental health. In the context of global climate change, more scholars are focusing on the relationship between climate change and the transformation of land use types, while research on the response relationship between land use types and pollutant accumulation at the end of the entire system is scarce. This study systematically analyzed the bioavailability and migration dynamics of heavy metals in soils of different land use types in the Qinghai Tibet Plateau watershed, providing solid data support for ecological protection and high-quality development of the plateau watershed, and offering new research ideas for water environment security in the Qinghai Tibet Plateau under the background of climate change.

Water is essential for all life, yet it faces increasing threats from contamination due to various human activities and natural processes [...]

Application of wheat straw could contribute to a sulfur-driven reduction in cadmium (Cd) bioavailability under reducing conditions induced by organic matter degradation. A pot experiment was conducted in organic matter deficient paddy soil under waterlogged conditions to assess the effects of sulfur (S, 30 mg kg−1), wheat straw (W, 1.0%), and their combination (WS) on Cd availability and accumulation in rice (Oryza sativa L.). Sulfur application alone increased Cd uptake in rice, whereas straw addition significantly reduced Cd accumulation, with WS achieving the greatest reduction. The mitigating effect was attributed to CdS precipitation and co-precipitation with FeS/FeS2 under straw amendment, as well as enhanced iron plaque formation on roots, which restricted Cd uptake. In contrast, in OM-deficient soil, sulfate promoted Cd mobilization in pore water due to limited electron supply for sulfate reduction. Compared with other sulfur forms, sulfate is more readily absorbed by rice, thereby synergistically enhancing Cd uptake by rice and promoting Cd translocation in different rice tissues. However, straw amendment supported reduction in sulfate, reducing Cd uptake by rice compared with S supplement alone. Overall, wheat straw amendment enhanced sulfur-mediated immobilization of Cd and effectively decreased Cd accumulation in rice.