In the context of green and sustainable remediation (GSR), carbon emissions from cement kiln co-processing of contaminated soil (CKCS), which is the most common soil remediation technology in China, have attracted considerable attention. However, the carbon accounting methodology for CKCS remains inadequately developed. To characterize carbon emissions from CKCS and explore pathways toward low-carbon development, this study developed a full-process carbon accounting framework and national inventory for CKCS using data on 335 cases in China. Two conceptual allocation approaches-the Difference-Based Method (DBM) and the Proportional Allocation Method (PAM)-were compared to address the sensitivity of carbon accounting to the assumptions made in the definition of the system. Within the framework, the decomposition of soil organic carbon (SOC) was identified as an important emission source, suggesting that widespread application of CKCS potentially led to the permanent loss of soil carbon stocks in China. Nationally, based on 335 CKCS cases from 2015 to 2023, CKCS generated 552,400 t COQ at an average intensity of 56.99 kg COQ per ton of soil, with provincial emission intensities ranging from 27.48 to 98.48 kg COQ per ton of soil. Optimizing soil transportation and allocation with improved fuel consumption demonstrated a mitigation potential of 10.45% in carbon emissions and a 30.9% reduction in costs. Spatial analysis further identified Beijing, southern and central Hebei, central Shanxi, and northern Anhui as the regions with the greatest potential for low-carbon CKCS deployment. These findings provide a scientific basis and decision-making guidance for standardized carbon accounting, differentiated remediation technology selection, and spatial planning of CKCS, thus supporting the low-carbon development of CKCS and advancing GSR in China.

Soil contamination by polycyclic aromatic hydrocarbons (PAHs) has emerged as a global environmental challenge due to their toxicity, bioavailability and persistence. Here, this study developed an improved hybrid framework combining PAH diagnostic ratios (DRs), PMF model, MCR-WALS model, and Two-dimensional Monte Carlo simulation (2D-MCS)-based HHRA model to assess the contamination status, source apportionment and ecological-health hazard of PAHs in soils around an abandoned coking plant. The results demonstrated that the average concentrations of BaA, BbF, BaP, InP and DahA exceeded local background values, indicating a high pollution level and an elevated ecological risk within the study area. The PMF model identified four sources of PAHs pollution: coking tar (34.2%), petroleum combustion (33.3%), biomass combustion (10.5%), and coal combustion (22.1%), and the factor profiles of PAHs were further validated by the results of DRs method and MCR-WALS model. The 2D-MCS-based health risk assessment showed that the ILCR values for all seven PAHs in children exceeded the permissible risk threshold of 1E−06, indicating a higher cancer risk for children than for adults, with BaP being the largest contributor to TCR. Petroleum combustion was identified as the priority control source and the largest source contributor to TCR. BaP was identified as the priority control pollutant and the largest PAH contributor to TCR. Among three exposure routes, the ILCRAF was the largest contributor to TCR, accounting for 55.7% in children and 58.7% in adults. The permissible dermal contact should be limited to AF < 4.96E-03 mg/cm² for children and AF < 5.07E-03 mg/cm² for adults to ensure a safe risk level. This study provides a more reliable framework for quantitative source apportionment and associated health hazard of soil PAHs caused by coking and industrial activities.

In recent years， per- and polyfluoroalkyl substances （PFASs） have been frequently detected in various environmental media and have attracted increasing attention due to their environmental persistence and toxicological characteristics. While investigations of PFASs concentrations in point source-contaminated environments have become increasingly comprehensive， studies focusing on PFASs levels in agricultural soils remain limited. Sixteen agricultural soil samples were collected from Shandong Province， and 27 target PFASs were detected， with total concentrations ranging from 0.325 to 3.717 μg·kg-1. Legacy PFASs accounted for 83.90% of the total concentration， while emerging PFASs represented 13.19%， with perfluorooctanoic acid （PFOA）， perfluorooctane sulfonate （PFOS）， and perfluorohexane sulfonate （PFHxS） being the dominant compounds. To identify potential sources of PFASs in the agricultural soils， principal component analysis （PCA）， positive matrix factorization （PMF）， and an assessment of surrounding industrial activities were employed. Source apportionment results indicated that emissions from electroplating， textile， and paper industries were likely the primary contributors to the dominance of legacy PFASs in the soils， with a contribution rate of 82.9%. Emerging and precursor PFASs were potentially derived from atmospheric transport， as well as emissions from the leather and surfactant industries， contributing 83.0% and 86.7%， respectively. Ether carboxylic acids were mainly associated with the rubber industry， contributing 83.2% of the observed pollution. This study provides baseline data on PFASs in agricultural soils， which is essential for informing management and regulatory decisions related to PFASs contamination in agricultural soils.

Mining-impacted groundwater is controlled by coupled source release, human exposure and contaminant migration, yet these processes are often assessed separately. This study developed an integrated source–exposure–transport framework for groundwater affected by Pb, Cd, As, Hg and cyanide (CN⁻) in a mining area. The framework combined PCA–APCS–MLR source apportionment, United States Environmental Protection Agency (USEPA)-based health risk assessment with Monte Carlo simulation, Groundwater Modeling System (GMS)-based plume transport modeling and Bayesian uncertainty optimization. Results showed that groundwater contamination was mainly associated with mining-related inputs and unresolved residual contributions, while oral ingestion was the dominant exposure pathway. Cd and As were the main health-risk contributors, whereas CN⁻ and Cd showed stronger receptor-oriented migration concern. Bayesian optimization helped identify pollutant-specific control priorities and robust receptor-protection indicators. The proposed framework links source diagnosis, exposure consequence and plume control, and provides a practical basis for risk-based groundwater management in mining-impacted aquifers.

The energy-intensive nature of gas thermal desorption strategies, along with their associated environmental impacts, particularly greenhouse gas emissions, has raised widespread concern. Using the life cycle assessment framework, this study conducted the first comparative analysis of in situ and on-site ex situ twin strategies, employing the same energy source and remediation principles from a unit process perspective. The results reveal that in situ gas thermal desorption exhibits significantly higher energy consumption (1.9 & times; ), normalized lifecycle environmental impacts (nearly 4 & times; ), and greenhouse gas emissions (more than 2 & times; ) than on-site ex situ strategy for the remediation of 1 m3 of contaminated soil. Both technologies rely on fossil fuels for over 97% of their energy mix, with natural gas, electricity, and concrete being the primary contributors to greenhouse gas emissions. Unit process analysis further identifies that heating in the in situ strategy is the main driver of its environmental impacts, as the high temperature requirement significantly increases energy consumption. In contrast, off-gas treatment in on-site ex situ strategy is the main source of life cycle greenhouse gas emissions. Reduction potential analysis reveals that optimizing heating in in situ gas thermal desorption can reduce greenhouse gas emissions by 68.24%, while optimizing off-gas treatment in on-site ex situ strategy can reduce emissions by 51.81%. This study highlights the significant environmental performance differences between the two technologies and provides a scientific foundation for developing targeted emission reduction strategies at unit process level.

Per- and polyfluoroalkyl substances (PFASs) are a class of persistent pollutants, and China’s electroplating industry is a major source of their emissions. This paper systematically reviews the sources, occurrence characteristics, and treatment technologies of PFASs in electroplating wastewater. The chrome plating process is the primary source of PFASs, with concentrations of perfluorooctane sulfonic acid (PFOS), 6:2 fluorotelomer sulfonate (6:2 FTS), and 6:2 chlorinated polyfluoroalkyl ether sulfonate (6:2 Cl-PFESA, F-53B) in some chromium mist suppressants reaching up to 985, 735, and 875 g/kg, respectively. Monitoring data from 15 electroplating parks and 97 enterprises revealed that 29 PFAS were detected in electroplating wastewater, with long-chain compounds dominating and PFOS concentrations reaching up to 3.6 × 107 ng/L. Non-target screening further identified the widespread presence of various concealed PFAS, including monohydro-substituted perfluorobutanoic acid (H-PFBA) and sodium p-perfluorous nonenoxybenzenesulfonate (OBS). Regarding treatment technologies, coagulation/flocculation showed very poor PFAS removal efficiency; flotation achieved up to 88% removal of perfluoroalkane sulfonic acids (PFSAs) but was constrained by process integration; biological treatment led to an increase in dissolved-phase PFAS concentrations; ion exchange resins achieved 98% removal of PFOS but were ineffective for short-chain PFASs due to their low affinity and rapid breakthrough; membrane technology achieved nearly 100% removal of long-chain PFASs but faced challenges, such as membrane fouling and concentrate disposal. This paper aims to provide a reference for PFAS pollution control in China’s electroplating industry.

Molecular diversity of dissolved organic matter (DOM) drives the differential of hydroxyl radicals (center dot OH) formation during Fe-bearing clay minerals (Fe-CM) oxygenation. However, the specific effects of multiple types of DOM on center dot OH formation, particularly focusing on investigating the transformation of reactive Fe species and DOM molecular perspective, remain inadequately understood. Here, we explored the effects of six types of DOM on center dot OH formation during reduced montmorillonite (rSWy-3) oxygenation. Adding DOM accelerated the center dot OH formation rates during rSWy-3 oxygenation. Humic acid or natural organic matter promoted 2.1 %-203.0 % center dot OH yield, but exhibited different concentration dependencies. Fulvic acid promoted center dot OH formation at high concentration (250 mg/L, increase by 174.4 %-180.5 %). DOM accelerated the conversion of surface-bound Fe (II) to dissolved Fe2+, and enhanced the oxygenation of trans-coordinated octahedral Fe(II) in reactive structural Fe(II) by direct electron transfer or indirect structural rearrangement. These synergistic processes mediated by DOM promoted center dot OH formation during rSWy-3 oxygenation. High-resolution mass spectrometry revealed that highly unsaturated molecules with 0.17 < (DBE-O)/C <0.28, including lignin and aromatic structure compounds with 0.27 < O/C < 0.56, enhanced center dot OH formation at low DOM concentration (50 mg/L). These molecules exhibited the inhibition phenomenon for center dot OH formation at high DOM concentration. The findings offer molecular-level perspectives on the mechanism of DOM-mediated center dot OH formation during Fe-CM oxygenation.

Effective management of such sites is crucial, yet the groundwater environmental risks associated with clusters of hazardous waste facilities in coastal cities are underexplored, hindering targeted remediation. This study aims to characterize the pollution features, assess ecological risks, and identify the sources of groundwater contaminants at five typical disposal sites within a coastal industrial park of East China. Results indicated that Groundwater pollution varied significantly among the sites. Site 4, associated with electroplating/metallurgy, was the most severely contaminated, with Fe and Mn exceeding standards by up to 51 and 74 times, respectively, and was classified as a "Considerable Ecological Risk" (RI = 336.23), primarily driven by Ni and Mn. Other sites exhibited lower but increasing pollution, largely influenced by site-specific processes like acid leaching and sodium hypochlorite use. Multivariate analysis categorized pollutants into three distinct groups: a) a geological group (Fe, Mn, Al) linked to granite weathering; b) an industrial waste-derived group (Cd, Ni, NH3-N) showing strong correlations of co-migration due to ammonia complexation; and c) independent sources group (As from etching waste, and widely distributed Pb). Contaminant migration was found to be co-influenced by groundwater flow and redox conditions. Management strategies should integrate natural background and industrial influences. Sites should enhance monitoring of Fe, Mn, and NH3-N in key processes, optimize production controls, and trace leakage points. The findings develop an integrated assessment framework combining pollution indices, ecological risk evaluation, and statistical source apportionment, and provide data basis and technical support for precise, risk-based groundwater protection strategies in industrial zones.

Arsenic (As) contamination in soil is a major environmental concern due to its grave threat to human health and ecosystems. In this paper, 2250 soil samples were collected to assess the speciation, bioaccessibility, and human health risk of As in soils from a legacy nonferrous metal smelter, as well as to simulate the As transport from contaminated soil into groundwater. The results indicated that 3.5% of soil samples exceeded the risk screening value (RSV), with the highest exceedance rate (9.54%) observed at a depth of 1.0 m. The proportion of water-soluble As and surface-adsorbed As (12-49%) exhibited a positive correlation with the total As concentration. The bioaccessibility of As (BioAs) ranged from 7.77% to 28.11%. Human health risk assessment (HHRA) based on total As concentration indicated unacceptable risk levels (CR > 1 ×10⁻⁶; HQ > 1), whereas risk values based on bioavailable and bioaccessible concentrations were reduced by 58-63%, suggesting a substantial overestimation of actual health risks. EPACMTP model suggested that the predicted As concentrations in groundwater ranged from 1.61 to 7.20 µg/L that are within the standard limit of 0.01 mg/L, indicating a low risk of groundwater contamination by arsenic. Arsenic level was significantly attenuated by 44.35-fold to 110.07-fold during transport from surface soils through the vadose zone. Moreover, the subsequent dispersive transport of arsenic in groundwater was governed by its release kinetics from the soil. This study provides new insights into the fate, transport, and bioaccessibility of arsenic in soils and associated risks, offering a basis for reducing soil and groundwater contamination risks and optimizing remediation strategies.

Crops can accumulate heavy metals (HMs) from soil, leading to human exposure through dietary intake. However, the influence of interregional food trade on dietary HMs exposure remains underexplored. In this study, using data derived from existing literature, the occurrence and distribution patterns of six HMs, namely arsenic (As), cadmium (Cd), chromium (Cr), nickel (Ni), lead (Pb), and zinc (Zn), in soil and crops across China were investigated. Furthermore, the influence of food trade on human exposure to soil-derived HMs was assessed. The average total concentration of the six HMs in soil was 234.01 ± 29.54 mg/kg, while concentrations in rice and wheat were 16.06 ± 2.91 mg/kg and 22.48 ± 4.22 mg/kg, respectively. The hazard quotients (HQs) for As in rice exceeded 1 in the Central, Central Coast, South Coast, Southwest, and Northeast regions, indicating potential health risks. Interregional food trade significantly redistributed these risks. Through rice consumption, the Central and Northeast regions accounted for up to 36.78% and 45.08% of the daily intakes of As and Cd in other regions, respectively. Similarly, through wheat consumption, the Central and Southwest regions accounted for up to 51.33% and 25.97% of the daily intakes of As and Cd, respectively. This redistribution is largely attributed to the concentration of major crop production in the Central, Northeast, and Southwest regions. Overall, this study highlights the critical role of interregional food trade in modulating population health risks associated with contaminants, providing a more accurate and comprehensive assessment of dietary HMs exposure.

Perfluorooctanesulfonate (PFOS) is a persistent pollutant in soils due to its exceptional chemical and biological stability. Pyrolysis has been recognized as an effective technology for the remediation of PFOS-contaminated soil. However, its large-scale application faces challenges such as the requirement of high temperatures, long residence time, and corrosive off-gas treatment. The application of additives during pyrolysis is a promising strategy to overcome these challenges. In this study, six additives (Fe2O3, Fe3O4, CaO, Ca(OH)2, kaolinite, and MgO) were employed to improve PFOS removal from soil by pyrolysis. The effects of temperature, residence time, and removal efficiency with additives on the PFOS decomposition mechanism and economic benefits were systematically investigated. The results showed that all additives could allow for effective PFOS removal at a relatively low temperature (350 °C) and with a short residence time (30 min). Fe2O3 and CaO at a 5% dosage exhibited PFOS removal efficiency reaching 95.19% and 95.49%, respectively, which were 21.00% higher than that of the no-additive system. The thermodynamic analysis showed that the additives could reduce the activation energy (Ea) of PFOS pyrolysis, among which Fe2O3 showed the most significant effect (54.24 kJ/mol). Although additives exerted no significant effect on the type of PFOS decomposition products in soil, they effectively reduced the emission of acidic off-gases. Among them, CaO and Ca(OH)2 showed the most significant reduction by forming inorganic fluorides, followed by Fe2O3 and Fe3O4, through providing active sites. Economic analysis indicated that CaO had the lowest cost for PFOS removal (2.86 CNY/mg), followed by Fe2O3 (2.88 CNY/mg). Comprehensively considering PFOS removal efficiency, decomposition mechanism, economic cost, and pH of treated soil, Fe2O3 was identified as the optimal additive. This study provides new insights into the PFOS pyrolysis in soils, and proposes an energy-efficient remediation approach by reducing temperature, residence time, Ea, and off-gas emissions, which offers support for the large-scale application of this technology.

Soils at pesticide production sites typically exhibit complex mixed contamination profiles characterized by high residual concentrations and strong persistence due to the long-term, iterative production of multiple pesticide classes. However, research on multi-residue analytical methods currently produced mainstream pesticides in such complex matrices remains scarce. In this study, a multi-residue analytical method for 13 classes of pesticides (comprising 55 compounds, -0.7 ≤ logP ≤ 7.3) in soils from pesticide production sites was developed and validated based on a modified QuEChERS approach coupled with liquid chromatography-tandem triple quadrupole mass spectrometry (LC-MS/MS) detection. Suitable extraction and cleanup conditions were screened through a combination of single-factor optimization and interaction experiments, and the performance of the method was evaluated in comparison with a QuEChERS method developed for conventional soil matrices. The results demonstrated that the method achieved satisfactory recoveries for 53 target pesticides in both quartz sand and site soils, with values ranging from 70% to 120% and good precision (RSDs < 20%). The limits of quantification (LOQs) ranged from 0.5 to 5 μg/kg, and the calibration curves showed good linearity (R2 > 0.991). Fortified-recovery testing of 21 site-soil samples from seven provinces in China showed reliable determination of 50-54 pesticides. Furthermore, the method was successfully applied to 22 soil samples collected from three pesticide production sites with different production histories, identifying 35 target pesticides. It maintained reliable quantitative performance even under high-residue conditions (1.23 × 107 μg/kg). This study provides a reliable analytical basis for the investigation and risk assessment of mixed pesticide contamination in soils from pesticide production sites.

Emerging environmental contaminants increasingly accumulate in soil ecosystems, yet their chronic biological impacts on soil-dwelling organisms remain poorly understood. Here, we demonstrate that tris(2,4-ditert-butylphenyl) phosphate (AO168═O), a prevalent soil-borne contaminant formed through the oxidative transformation of the widely used plastic antioxidant (AO168), compromises nematode fitness at relatively low concentrations. Exposure of C. elegans to AO168═O induces pronounced developmental and physiological impairments, including suppressed somatic growth, delayed developmental progression, disrupted energy homeostasis, and reduced reproductive output at 400-10,000 ng/g. Transcriptomic profiling reveals a robust reprogramming of gene expression that molecularly corroborates growth and developmental restriction. Notably, longevity-regulating pathways centered on the conserved insulin/IGF-1 signaling (IIS) are consistently and significantly enriched. Integrated gene-set enrichment analyses further demonstrate that AO168═O-associated transcriptional signatures closely recapitulate established IIS- and DAF-16-regulated expression programs, which were functionally validated by pharmacological inhibition and genetic ablation. Furthermore, early-life exposure leads to persistent and long-lasting fitness deficits, such as impaired locomotor performance and a marked reduction in adult lifespan, detectable even at the lowest exposure concentration. Together, these findings identify AO168═O as a previously underrecognized factor compromising nematode fitness, providing essential laboratory-based evidence that highlights the potential vulnerability of soil biota to ubiquitous soil-borne contaminants.

Per- and polyfluoroalkyl substances (PFASs) are synthetic organic chemicals that are frequently detected in soil. Thermal treatment is an effective technique for removing PFASs from soil. However, the application of thermal treatment is a challenge because of the high energy consumption. Microwave heating (MWH) is proposed as an innovative thermal method for eliminating PFASs from soil. In this study, the removal efficiency, energy consumption and decomposition products were systematically investigated and compared with those of traditional electrical heating (EH). The results demonstrated that under optimal parameters (10 % moisture content, N2 condition, and resistance time of 30 min), MWH could effectively remove more PFASs from soil. Specifically, the removal efficiencies of perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) increased by 78.05 % and 24.82 %, respectively, at 200 °C and 300 °C via MWH. When the removal efficiency of PFASs reached over 95 %, the energy consumption of MWH was 74.33 %-76.19 % lower than that of EH. Decomposition mechanism of PFASs primarily included C-C and C-S bond cleavage and β-elimination defluorination. Additionally, MWH treated soil may be more effective in preserving soil fertility. This study provides new insights into efficient and energy-saving options for removing PFASs from soil.

Fluoroglucocorticoids (FGCs) in groundwater had brought significant risks to human health and ecological environment, while the traditional material such as zero-valent iron (nZVI) for groundwater remediation was low efficiency to remove these pollutants. A new material, humic acids coated zero-valent iron (HA@nZVI) particles, was designed and prepared here to promote removal of FGCs in groundwater from physical, chemical, and biological aspects. The results showed that compared with nZVI particles alone, HA@nZVI increased physical interception and biochemical degradation rate of FGCs in groundwater by 11.21 % and 43.02 %, respectively. Acidic surface functional groups of HA@nZVI such as carboxyl and carbonyls may promote its adsorption rate for strongly polar FGCs, and its lamellar network structure increased specific surface area by 1.8 times compared to nZVI. Biochemical degradation of FGCs occurred because HA@nZVI may promote reductive defluorination and biodegradation defluorination, which increased the chemical and biological removal of FGCs by 15.44 % and 29.13 % compared with nZVI alone. HA@nZVI may effectively inhibit the self-corrosion of nZVI in it, ensuring that the electron release rate of nZVI consistent well with the defluorination rate of FGCs. In addition, coated HAs provided a bridge for electron transfer among electron donor (nZVI), microorganisms, and electron acceptor (TA), which increased the electronic utilization of FGCs defluorination from 30.05 % to 79.28 %. Overall, this new material can effectively remove FGCs, giving technical support for the remediation of polluted groundwater.

High temperatures and providing sufficient time for the thermal desorption of persistent organic pollutants (POPs) from contaminated clay soils can lead to intensive energy consumption. Therefore, this article provides a critical review of the potential additives which can improve soil texture and increase the volatility of POPs, and then discusses their enhanced mechanisms for contributing to a green economy. Ca -based additives have been used to reduce plasticity of bentonite clay, absorb water and replenish system heat. In contrast, non -Ca -based additives have been used to decrease the plasticity of kaolin clay. The soil structure and soil plasticity can be changed through cation exchange and flocculation processes. The transition metal oxides and alkali metal oxides can be applied to catalyze and oxidize polycyclic aromatic hydrocarbons, petroleum and emerging contaminants. In this system, reactive oxygen species (center dot O2 - and center dot OH) are generated from thermal excitation without strong chemical oxidants. Moreover, multiple active ingredients in recycled solid wastes can be controlled to reduce soil plasticity and enhance thermal catalysis. Alternatively, the alkali, nano zero-valent iron and nano-TiN can catalyze hydrodechlorination of POPs under reductive conditions. Especially, photo and photo -thermal catalysis are discussed to accelerate replacement of fossil fuels by renewable energy in thermal remediation. (c) 2024 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.

Understanding the binding between per- and polyfluoroalkyl substances (PFAS) and proteins is essential for elucidating their toxicokinetics and tissue distribution. Here, we quantified the binding affinities of 14 PFAS to rat liver fatty acid-binding protein (rL-FABP) and rat serum albumin (RSA). Results showed that PFAS exhibit strong binding affinities (Ka) to the rL-FABP (103 ∼ 105 M-1), particularly among medium- to long-chain perfluorinated carboxylic acids (PFCAs). The binding affinity of PFAS to RSA ranged from approximately 104 to 105 M-1, with 1 to 4 binding sites. Molecular docking results supported that PFAS binding to proteins is an exothermic process driven by van der Waals forces, hydrogen bonding, and electrostatic interactions. Additionally, long-chain PFCAs were shown to adopt a "U"-shaped conformation within the ligand-binding cavities of rL-FABP and RSA. The newly developed physiologically based pharmacokinetic model using measured binding data demonstrates a substantial improvement in the goodness of fit to experimental observations, reducing the prediction error by 20 %∼216 %. Finally, we found that the PFAS liver-blood partition could be mainly explained by the binding affinity ratios of PFAS to liver and blood proteins, which could be further extrapolated from rats to humans, providing useful insights to understand the tissue distribution of PFAS.

Paddy soil represents a critical sink for microplastics (MPs), where frequent redox oscillations from wet-dry alternation can accelerate MPs aging, and alter dissolved organic matter (DOM) composition in paddy soil. However, this process remains poorly understood to date. Here, we systematically investigated the aging of three MPs and their structural effects on DOM in paddy soil during wet-dry alternation. Following the seventh wet-dry alternation (98 d), the weight loss of MPs followed the order polypropylene (PP, 13.83 %) > polyethylene (PE, 8.20 %) > polyethylene terephthalate (PET, 4.23 %). PET underwent limited hydrolysis, whereas PE and PP exhibited significant C-C cleavage and oxidation (C-O-C/C=O). Three MPs initiated aging via C-H bond cleavage, followed by polymer-dependent functional group transformations. Fourier transform ion cyclotron resonance mass spectrometry demonstrated a more obvious reduction in the average molecular weight of DOM in paddy soil amended by PP, while DOM exhibited the highest aromaticity and double bond equivalent in paddy soil amended by PET after the seventh wet-dry alternation. The unique molecules of DOM in paddy soil with PE and PP have a higher oxidized degree, but higher biodegradability in paddy soil with PET. These findings provide novel insights into chemical structure alterations of MPs and DOM formation during wet-dry alternation in paddy soil, contributing to more precise projections for the environmental risk of aged MPs in agricultural ecosystems.