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Reducing urban fine particulate matter (PM 2.5 ) concentrations is essential for China to achieve the Sustainable Development Goals (SDGs). Identifying the key drivers of PM 2.5 will enable the development of targeted strategies to reduce PM 2.5 levels. This study introduces a machine-learning model that combines CatBoost and the Tree-Structured Parzen Estimator (TPE) to analyze PM 2.5 concentration across 297 cities between 2000 and 2021. SHapley Additive exPlanations (SHAP) were employed to identify the primary factors influencing urban PM 2.5 concentrations. The study revealed that the proposed model has high accuracy in predicting urban PM 2.5 concentrations, achieving a coefficient of determination (R 2 ) score of 96.44%. Socioeconomic and industrial activity are key drivers of PM 2.5 concentrations. This study not only quantifies the primary factors exacerbating or alleviating pollution for each city or province during the 2000-2021 period but also evaluates the influence of operational factors such as technological and public financial expenditures. In 2000, the main contributors to pollution in four heavily polluted cities included substantial nitrogen oxide emissions, inadequate technology investments, and excessive population density and liquefied gas consumption. Due to the rapid reduction in nitrogen oxide emissions, pollution levels in these cities have improved substantially. In the future, the most effective strategies for pollution reduction in these cities will focus on controlling population density and slowing down mining development. The proposed framework serves as a robust evaluation tool and can propose tailored strategies to control PM 2.5 concentrations effectively in each city., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Wind farms (WFs) have grown significantly in recent years, especially in the offshore. However, their construction can adversely affect marine life and expose species to microplastics (MPs) pollution, posing a threat to human health through seafood consumption. In order to further understand the impact of WF construction activities on swimming animal resources and the accumulation of MPs ingested by dominant economic species occupying significant ecological niches, this study investigated changes in swimming animal resources over six periods during three years of WF construction in the South Yellow Sea and evaluated MPs ingestion in three economically valuable dominant species (Portunus trituberculatus, Collichthys lucidus, and Coilia nasus) before and after construction. The study found that the most significant negative impacts on swimming animal resources occurred during the early construction stages, with recovery observed as construction finished. By the operational phase in autumn 2021, all indicators had exceeded pre-construction levels from spring 2019, except for biomass, which had not fully recovered. MPs were identified in every biological sample, and the MPs contamination in the gills was higher than that in the gut and skin tissues. The average abundance of MPs and the overall MPs hazard index of the three organisms were higher than those in other areas and pre-construction levels. WF construction in the South Yellow Sea caused short-term negative impacts on swimming animal resources with long-term recovery, but the increased MPs pollution during the construction process requires continuous monitoring and management to achieve sustainable development., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Vehicle emissions are recognized as a primary source of particle-phase polycyclic aromatic hydrocarbons (PAHs), significant contributors to the hazardous properties of PM 2.5 . This study investigates the profiles of PAHs through measurements conducted in a tunnel and an urban roadside environment in 2020. We quantified real-world vehicle emission factors for mixed fleets in the Zhongshu tunnel in Guizhou, southwest China, and found that the total PAHs had an emission factor of 8.15 μg veh -1 km -1 , with higher factors observed for high-ring PAHs. Additionally, we analyzed concentrations of 15 PAHs at a roadside environment in Hefei, southern China, with an average concentration of 23.81 ng/m 3 . PAHs with 4, 5, and 6 rings comprised 80% of total PAHs at the roadside and 87% in the tunnel. Gasoline emissions were the predominant source in both the tunnel and roadside environments, supplemented by non-tailpipe emissions, catering, domestic cooking, and asphalt from road surfaces. Notably, while the total toxicity equivalent concentration of Benzo[a]pyrene (BaP) significantly exceeded the World Health Organization (WHO) guidelines of 1 ng/m 3 , the presence of additional compounds such as Dibenzo[a,h]anthracene (DahA) markedly increased the toxicological impact of PM 2.5 from vehicle emissions. Therefore, it is essential to implement targeted pollution control strategies in central urban areas that address not only the overall concentration of PAHs but also their specific toxic contributions Continuous monitoring and assessment of PAHs in the urban environment are indispensable for effectively reducing their health impacts., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Imidacloprid (IMI), a leading neonicotinoid insecticide, is widely used in China. Nevertheless, owing to its high toxicity to pollinators, regulatory scrutiny of its usage has increased in recent years. Despite this, no relevant issues have been announced in China, and its usage continues to rise. In this study, we systematically reviewed the development history, pollution characteristics, and environmental problems associated with IMI in China, which is imperative to promote its green development. The results show that most IMI products (97.1%) in China are registered for agricultural use. Owing to its extensive use and strong migration ability in different environmental matrices, IMI has been broadly detected in multiple environmental media. The average detection rate (DR) of IMI in soils, ambient water, and sediments were 90.7%, 81.3% and 84.5%, respectively, and the corresponding concentrations were 54.6 ± 83.8 ng/g dry weight (dw), 32.8 ± 103 ng/L, and 1.7 ± 2.9 ng/g dw, respectively, indicating high IMI abundance in multiple environmental media in China. The spatiotemporal distribution of IMI was generally determined by its application modes, transport, and degradation rates. IMI is commonly overused in China, leading to the development of high IMI resistance in many pests, and a high DR of IMI in food, drinking water, and human bodies. To alleviate IMI pollution in China, the joint efforts of the government, farmers, and scientists are necessary, including but not limited to formulating laws and regulations, strengthening governmental supervision, improving farmers' knowledge of IMI use, and promoting technological innovation in IMI and application methods., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Ozone pollution was widely reported along with PM 2.5 reduction since 2013 in China. However, the meteorological drivers for ozone varying with different regions of China remains unknown using explainable machine learning, especially during the COVID-19 pandemic. Here we first analyzed spatiotemporal variations of PM 2.5 and ozone from 2015 to 2022 in eleven urban agglomerations of China. PM 2.5 decreased in all regions, with the largest drop in Beijing-Tianjin-Hebei (BTH). In contrast, ozone declined initially but rose during the pandemic in most regions, especially in Cheng-Yu. Probability density curves showed pronounced increase (24.7%) and slight change in the proportion of PM 2.5 and ozone meeting the pollution criterions during the pandemic, respectively. Leveraging Random Forest with SHAP analysis, we further established ozone models in typical urban agglomerations with good performance (CV-R 2  = 0.80-0.90; CV-RMSE = 8.52-19.20 μg/m 3 ) during the pandemic, and compared their relative importance of meteorological variables. Particularly, temperature and incoming shortwave flux at top of atmosphere were identified with high importance in high-ozone regions such as Middle Plain and BTH. Increasing importance of PM (e.g., PM 10 ) was found in southern China, e.g., Yangtze River Delta and Pearl River Delta regions. The western China was characterized with more importance of meteorology, especially in Tibet. Surface albedo and sensible heat flux from turbulence were noted distinctively with high importance in Tibet, partly due to their impacts on ozone formation by generating heat source and sink. In addition, sea level pressure (SLP) was revealed with the highest importance (25.2%) in Cheng-Yu, consistent with the fact that synoptic patterns characterized by SLP field could affect ozone pollution in Sichuan Basin. Our results not only provide an understanding of meteorological factors in regional ozone formation in China, but also highlight the feasibility of explainable machine learning in ozone studies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Elucidating the chemical composition, sources, and health risks of fine particulate matter (PM 2.5 ) is crucial for effectively preventing and controlling air pollution. This study collected PM 2.5 samples in Linyi from November 10, 2021, to October 15, 2022, spanning the period of the 2022 Winter Olympics and Paralympics. The analysis focused on seasonal variations in the chemical composition of PM 2.5 , including water-soluble ions, inorganic elements, and carbonaceous aerosols. Results from the random forest model indicated that control measures during the Olympics and Paralympics reduced PM 2.5 concentrations by 21.5% in Linyi. Organic matter was the dominant component of PM 2.5 , followed by NO 3 - , SO 4 2- , and NH 4 + . Among secondary inorganic ions, SO 4 2- exhibited the highest concentration in summer, while NO 3 - and NH 4 + showed the lowest concentrations. The inorganic elements S, K, Fe, and Si had high mean annual concentrations, underscoring the need for targeted control measures for plate production, bulk coal burning, and biomass combustion in Linyi. The organic carbon (OC) to elemental carbon ratio (17.7-20.5) in Linyi was high, highlighting the importance of addressing secondary OC pollution. According to the positive matrix factorization model, coal burning, and the secondary formation processes of sulfate and nitrate were the dominant sources of PM 2.5 . Backward air mass trajectories revealed substantial contributions from the southeastern, local, and southwestern regions of Linyi. This suggests the need for enhanced regional joint prevention and control efforts between Linyi and neighboring cities, such as Rizhao and Jining in Shandong Province, as well as northern cities in Jiangsu Province. The highest non-carcinogenic and carcinogenic risks (CRs) were associated with As. coal burning posed significant noncarcinogenic risks and a moderate CR, contributing 41.7% and 44.0% of the total health risk, respectively. These findings are crucial for developing effective air pollution prevention and control strategies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

In recent years, jellyfish outbreaks have been frequent in near-shore waters and have become a worldwide problem. At present, the main species that form jellyfish disasters along the coast of China is aurelia. In order to control jellyfish outbreaks from the source of growth, this paper proposed a hydroid detector HD-YOLO improved from YOLOv7, and established a hydroid of aurelia dataset. Firstly, the original dataset was established by acquiring images of hydroids via the web, in the laboratory and undersea photography. Secondly, MSRCR, a multi-scale enhancement algorithm with color recovery, was used to improve the underwater image quality. Then the dataset is augmented by the combination of Mosaic and Mixup. Finally, the effectiveness of HD-YOLO, underwater image enhancement and dataset augmentation methods were verified through a series of comparative experiments. This study provides a more accurate and faster method for the hydroid of aurelia detection and a more generalised dataset., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study investigated 17 organophosphate esters (OPEs) in the surface sediments of Hangzhou Bay and the East China Sea. The mean concentration of ∑OPEs in Hangzhou Bay (235.3 ng/g) was slightly lower than that in the East China Sea (273.5 ng/g), with detected analytes dominated by Diethyl phosphate, Tris(2-chloropropyl) phosphate, and Tris(1-chloro-2-propyl) phosphate. Based on principal component analysis and cluster analysis for the source apportionment of OPEs, the results indicated that the high levels of OPEs in the East China Sea close to Yangtze River estuary can be attributed to a significant large-scale OPEs production site located along the southern Yellow Sea and the western coast of the East China Sea. Furthermore, the risk assessment conducted on aquatic organisms indicated the non-ecological risk of OPEs. However, future research should focus on the potential composite impacts of OPEs on the water systems and human health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The vertical distribution, sources and influencing factors of polycyclic aromatic hydrocarbons (PAHs) in soil across ecosystem habitats were investigated around the Liaohe River Estuary (LRE) Wetland. The concentration of Ʃ 16 PAHs ranged from 41.0 to 435.4 ng g -1 dw, with a predominance of low molecular weight PAHs. Overall, PAHs and physicochemical properties of soil decreased with depth. Vegetation was found to increase soil PAHs. Additionally, soil physicochemical properties also regulated PAHs concentration, particularly for PAHs with high molecular weight. Among the habitats, total organic carbon was the key influencing factor for Suaeda heteroptera, while specific surface area was crucial for Phragmites australis. Results of characteristic ratio method and principal component analysis revealed that PAHs in LRE primarily originate petroleum, coal and biomass combustion. In summary, vegetation colonization significantly affected the distribution, sources, and controlling factors of PAHs. These findings are meaningful for management of soil PAHs across various ecosystem habitats., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The Jiaozhou Bay (JZB) intertidal zone is a significant carbon reservoir that plays a crucial role in transporting and accumulating organic matter; however, quantitative studies of organic matter sources are scarce. In this study, we present bulk parameters of total organic carbon (TOC), TOC/TN, δ 13 C, and biomarker contents in 36 surface sediment samples from the JZB intertidal zones to quantify the contribution of organic carbon (OC) derived from terrestrial/marine sources, such as C 3 plants, C 4 plants, estuarine productivity, sewage outlets, and marine productivity. The results demonstrated that a two-end-member model based on the traditional indicators of TOC/TN or δ 13 C is not appropriate for quantifying the OC source. The presence of C 3 plants, C 4 plants, and sewage outlets in the JZB intertidal zone could lead to errors in determining OC contribution when solely using TOC/TN or δ 13 C. A classical mixing diagram (three-end-member model) utilizing TOC/TN and δ 13 C values revealed that OC contribution was dominated by marine productivity throughout the intertidal zone. In the west, the average OC contribution from marine productivity, estuarine productivity, and C 4 plants was 73.8 %, 14.2 %, and 12.0 %, respectively. In the east, the average OC contribution from marine productivity, estuarine productivity, and sewage outlets was 57.6 %, 24.9 %, and 17.4 %, respectively. The higher OC contribution from marine productivity in the west was attributed to the occurrence of Spartina alterniflora, while the OC contribution from estuarine productivity in the east was primarily due to the presence of more rivers flowing into the JZB compared to the west. By combining biomarkers and OC contents, a significant positive relationship verified the suitability of the end-member values selected for the three-end-member mixing model in the west and east intertidal zones of JZB. This finding was further supported by principal component analysis (PCA) analyses of these proxies. This study demonstrated that OC sources in intertidal zones varied among contrasting coastal environmental conditions and addressed the knowledge gap regarding biogeochemical cycles and ecological protection in the JZB intertidal zones., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Organophosphate esters (OPEs) are emerging pollutants and used extensively in industrial production as alternative to the traditional flame retardants. This study investigated the contamination characteristics and health risks of OPEs in 104 mollusks from 15 cities along the coastal region of South China. Σ8OPEs ranged from 48.2 to 1937 ng/g dw, with a mean value of 295 ng/g dw. TDCIPP, TCPP, and TCEP were the dominant OPEs. Different spatial distributions were observed, with higher concentrations in Guangdong Province. A statistically positive but non-significant linear correlation was found between the trophic level of mollusk and OPEs concentration. The trophic magnification factors were >1, suggesting that OPEs have the potential to biomagnify in mollusks. OPEs in mollusks pose low non-carcinogenic and carcinogenic risks to consumers. This study provides an important basis for managing the safety risks associated with OPEs in mollusks., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Accurate predictions of atmospheric particulate matter can be applied in providing services for air pollution prevention and control. However, the forecasting accuracy of traditional air quality models is limited owing to model uncertainties. In this study, we developed a deep learning model, named multiscale depth-separable UNet (MDS-UNet), to improve PM 2.5 and PM 10 concentration forecasts from WRF_Chem over China. Results showed that MDS-UNet was able to capture the complex nonlinear errors between model predictions and observations, which was helpful in correcting the biases and spatiotemporal distribution patterns of PM 2.5 and PM 10 concentrations predicted by WRF_Chem. MDS-UNet made a better performance in the improvement of both PM 2.5 and PM 10 prediction accuracy than UNet and CNN during the 0-24 forecasts. Using MDS-UNet, the reductions in the root-mean-square error (RMSE) of the regionally averaged PM 2.5 and PM 10 concentration forecasts were 35.08% and 17.74%, respectively. During the 0-24-h forecast period, MDS-UNet performed well in terms of PM 2.5 and PM 10 over six key urban agglomerations in China. Taking a pollution process as a case study, results demonstrated that, compared with WRF_Chem, MDS-UNet was able to make the best improvement in YRD, the Sichuan Basin, and central China, with reductions in the RMSE of the PM 2.5 forecasts of 55.22%, 55.53%, and 52.17%, respectively; and for PM 10 forecasts these reductions were 44.90%, 40.97%, and 46.79%, respectively. Through this analysis, it was apparent that MDS-UNet demonstrated a better effect in terms of improving both PM 2.5 and PM 10 predictions in these key urban agglomerations during an important pollution process., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Hongnian Liu reports financial support was provided by National Natural Science Foundation of China. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

An in-depth investigation of the maximum environmental load is crucial for soil security and pollution prevention. This research focused on soil environmental carrying capacity (SECC) for different risk receptors in a Chinese industrial city. By determining risk threshold for various land use types, we integrated mass balance and iterative models to capture dynamic net input fluxes with spatial heterogeneity. This enabled quantitative characterization of Benzo(a)pyrene (BaP) SECC through top-down and bottom-up approaches (corresponding to duration (D) and rate of regional emission, respectively). The thresholds were in the order of agricultural land < residential land < forest < industrial land < park. The top-down analysis showed D increased ∼1.5x with a 5% input flux decline until 2031. The bottom-up analysis suggested industrial emissions decreased by approximately 10% as the pollution control period was extended from 20 to 50 years. Both methods showed that at maximum background values (C 0 ), D was ∼4x and the industrial emission rate was ∼10% higher than at minimum C 0 . SECC values near industrial areas significantly decreased, even reaching negative values, signifying complete carrying capacity loss. This study provided an approach to the dynamics of SECC under diverse scenarios, aiding informed decision-making for sustainable land management., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Groundwater is a vital natural resource that has been extensively used but, unfortunately, polluted by human activities, posing a potential threat to human health. Groundwater in the Yinchuan Region is contaminated with NO 3 - , which is harmful to the local population. This study utilized the eXtreme Gradient Boosting (XGBoost) model with the SHapley Additive exPlanations (SHAP) method to identify the key factors influencing groundwater nitrate pollution in the Yinchuan Region. The SHAP feature dependence plots revealed the intricate relationship between NO 3 - levels and TDS, Mn 2+ , TFe, and pH in complex groundwater systems. The results indicate that the high levels of groundwater NO 3 - are primarily caused by the combined effect of irrigation water from the Yellow River, shallow groundwater depth, unfavorable drainage, water recharge, overuse of fertilizers, and geological factors such as weathering nitrogen-bearing rocks. Hydrochemical parameters such as Mn 2+ , Fe 2+ , and pH create a strong reducing groundwater environment, resulting in lower NO 3 - concentrations in this region. Well depth and soil organic carbon at a depth of 80-100 cm have a negative impact on NO 3 - concentrations; conversely, sand in soil depths 0-20 cm and 100-150 cm and climatic factors such as precipitation have a weak but positive effect on the level of NO 3 - in groundwater in the region. The recommendation is to quickly and extensively implement a farming water-conservancy transformation project, reducing water-intensive crops, promoting groundwater use for irrigation in areas where soil salinization is a concern are proposed. This research could provide local agencies with a scientific foundation for sustainable management of farming and groundwater in the Yinchuan Region, ultimately benefiting the entire Yinchuan Plain., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Mineral exploitation is one of the human activities that seriously affect freshwater ecosystems. It is of great significance to study the impact of mining on the α and β diversity of macroinvertebrates. This study reveals the response of taxonomic and functional α and β diversity of macroinvertebrates to mining activities in the Luanchuan molybdenum mining area. A total of 40 sets of macroinvertebrates, sediment and water samples in the Taowan North River (TR), Yu River (UR) and Hongluo River (HR) in the molybdenum mining area were collected. The results show that: 1) the mining activities led to obvious differences in the environmental factors of the three rivers. The heavy metals in the sediments and water bodies of TR and UR showed different degrees of exceedance, while there was no exceedance of heavy metals in HR; 2) The taxonomic and functional α diversity was much lower in the TR and the UR than in the HR. The concentrations of heavy metals in sediments and water bodies were significantly negatively correlated with the taxonomic and functional α diversity; 3) Mineral extraction resulted in significant differences in macroinvertebrate β diversity among the three rivers. The taxonomic and functional β diversity of the macroinvertebrate communities in TR and UR was much higher than that in HR. The turnover and nestedness of functional β diversity showed significant differences. Functional β diversity was more obviously affected by heavy metal exceedance than taxonomic β diversity. Nestedness were more sensitive to exceedance of heavy metals than turnover. The results of this study can provide a theoretical basis for ecological restoration and protection of rivers in mining areas., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Na Zhao reports financial support was provided by National Natural Science Foundation of China. Na Zhao reports financial support was provided by Henan Provincial Science and Technology Research Project. Ruixue Cao reports financial support was provided by Henan Provincial Science and Technology Research Project. Na Zhao reports financial support was provided by Young Backbone Teacher Project of Henan University of Science and Technology. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Obtaining the high-resolution distribution characteristics of urban air pollutants is crucial for effective pollution control and public health. In order to fulfill it, mobile monitoring offers a novel and practical approach compared to traditional fixed monitoring methods. However, the sparsity of mobile monitoring data still makes it a challenge to recover the high-resolution pollutant concentration across an entire area. To tackle the sparsity issue and fulfill a prediction of the spatiotemporal distribution of PM 2.5 , a high-resolution urban PM 2.5 prediction method was proposed based on mobile monitoring data in this study. This method enables prediction with a spatial resolution of 500m × 500m and a temporal resolution of 1 h. First, a Light Gradient Boosting Machine (LightGBM) was trained using mobile monitoring of PM 2.5 concentration and exogenous features to obtain complete spatiotemporal PM 2.5 concentration. Second, a model consisting of Convolutional Neural Network and Transformer (CNN-Transformer) with a customised loss function was established to predict high-resolution PM 2.5 concentration based on complete spatiotemporal data. The method was validated using real-world data collected from Cangzhou, China. The numerical results from cross-validation showed an R 2 of 0.925 for imputation and 0.887 for prediction, demonstrating this method is suitable for high-resolution spatiotemporal prediction of PM 2.5 concentration based on mobile monitoring data., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Lakes are vital sources of drinking water and essential habitats for humans and various other living organisms. However, many lakes face organic pollution due to anthropogenic disturbance and climatic influence, and the spatiotemporal changes of organic pollution in lakes over a large area are still unclear. Based on three monitoring datasets of chemical oxygen demand (COD) in 390 lakes, this study demonstrated the apparent spatiotemporal differences of organic pollution in lakes during the 1980s-2010s and the effects of water eutrophication and salinization. Throughout China, lake organic pollution showed a general spatial trend of being more severe in the north compared to the south. This pattern is reflected in the positive linear correlations between in-situ COD concentrations and lake latitude, observed in both the 1980s (p < 0.05) and the 2010s (p < 0.01). In terms of spatial differences, the influence of total nitrogen concentrations increased from 0.27% in the 1980s to 35.24% in the 2010s. Moreover, with increasing human activity, 78.31% of the studied lakes (N = 83) showed increasing COD concentrations during the 1980s-2010s. In addition, the logarithmic dissolved organic carbon concentrations were linearly correlated with log water conductivities (Pearson's r = 0.49, p < 0.01), suggesting that lake expansion would attenuate organic pollution in saline lakes through dilution effects. These results are valuable for understanding the spatiotemporal dynamics of organic pollution and are crucial for effective management of organic pollution in different lakes., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Microplastics (MPs) pollution has emerged as a global concern. To mitigate the potential threats by MPs, particularly to coastal regions, it is crucial to comprehend the environmental behavior of MPs and their affiliated chemicals. In the present study, we collected floating MPs using a Manta net (0.33 mm mesh size) in a one-year sampling event in 2022 from the eight major estuaries in the Pearl River Delta, China, and also from five coastal sites in August and December in the same year. Nineteen linear alkylbenzenes (∑ 19 LAB) and 16 polycyclic aromatic hydrocarbons (∑ 16 PAH) affiliated with MPs were measured. The mean concentrations of MPs-affiliated ∑ 19 LAB and ∑ 16 PAH were 6710 (range: 3400-12300) and 5310 (range: 817-19,600) ng g -1 , respectively, at the estuarine sites, and were 4920 (range: 2400-7600) and 2610 (range: 911-7890) ng g -1 , respectively, at the coastal sites. Significant correlations were found between logarithmic MPs-water partition coefficients (log K pw ) and logarithmic suspended particulate matter-water partition coefficients (log K d ) values for LABs and PAHs, indicating analogous partitioning dynamics for MPs and suspended particulate matter with water. The annual riverine outflows were 1170 and 414 g for ∑ 19 LAB and ∑ 16 PAH, respectively. Although the riverine outflows of LABs and PAHs carried by MPs remain negligible compared to those by suspended particulate matter, an upward trend was identified between 2018 and 2022. Notably, the riverine input of LABs and PAHs carried by suspended particulate matter to the coastal ocean decreased from 2005/2006 to 2022, due to a combination of improved technological processes and energy structures., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

To understand the characteristics and pollution status of heavy metals in the intersection areas of Laizhou Bay and the Yellow River Estuary in Shandong Province, the contents of various heavy metals in surface seawater samples collected from this area in August 2022 were detected. The spatial distributions of the heavy metals were analysed, which exhibits a general decreasing trend in the concentrations of Hg, As, Cr, and Pb from west to east, while Cd, Zn, and Cu show the opposite trend. The average single-factor index P values decrease in the following order Pb > Zn > Hg > Cu > As > Cd > Cr, among which Pb, Zn, Hg, and Cu caused pollution in this area. The potential ecological risk index values indicate that the main heavy metal pollutants in study area are Hg and Pb, with Hg having the highest value, accounting for 74.7%, and being the main potential ecological risk factor. Correlation analysis shows that the most significant environmental factor affecting heavy metal content is salinity. According to the interactive heatmap between cluster analysis and station classification, the heavy metals have originated from industrial, agricultural, and domestic sewage discharge, surface runoff, river inputs, seawater aquaculture, maritime transportation, and fuel exhaust emissions. This research hopes to provide some reference value for the protection of marine and estuarine ecosystems., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Groundwater is the principal water source of drinking and irrigation in the Dawen River Basin of Shandong Province. Thus, its investigations and evaluations are of significant importances. Based on collected groundwater samples, this study employed a combination of the entropy-weighted water quality index(EWQI), Nitrate Pollution Index(NPI) and the human health risk assessment(HHRA) model to evaluate groundwater quality and associated health risks. The combination of EWQI and NPI provides a more refined classification of groundwater quality in the Dawen River Basin. Geostatistical and GIS spatial analysis methods are employed to analyze the spatial characteristics of groundwater quality and its relationship with geomorphology. Results indicate that the region generally enjoys good water quality, with Entropy Water Quality Index (EWQI) values ranging from 20.32 to 302.37, and an average of 70.88. Downstream quality is poorer than upstream, and flat terrains typically exhibit poorer water quality. The major indicators affecting groundwater quality include Na⁺, Cl⁻, SO₄ 2 ⁻, and NO₃⁻. The NPI results show that due to differences in anthropogenic sources, 38.1%, 27.38%, 26.19%, 4.76%, and 3.57% of the groundwater samples are classified into non-polluted, slightly polluted, moderately polluted, significantly polluted, and extremely significantly polluted types, respectively. The HHRA model reveals high potential non-carcinogenic risks for NO₃⁻ and low risks for F⁻ in the study area. The health risks associated with high levels of NO 3 - in the areas surrounding Dongping Lake and Ningyang County are greater than in those other regions and therefore should be a significant concern for public health. Furthermore, this study attempts to combine the EWQI and NPI to categorize groundwater protection and governance statuses into four types: protective, utilizable, preventive, and remedial. This approach addresses the shortcomings in comprehensively identifying water quality types by single evaluation methods and offers valuable insights for distinguishing water quality types under nitrogen pollution conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The macroplastics (MaPs) and microplastics (MiPs) polluting agricultural soils raise great concerns. Unfortunately, scientists know little about the occurrence of MaPs/MiPs in soil among different farming systems. In this study, we analyzed MaPs/MiPs in soils (0-30 cm) collected from six different farming systems (wheat-maize rotations, cotton, vegetables, permanent orchards, greenhouses with and without mulching) in Quzhou county, the North China Plain, by using fluorescence microscope and micro-Fourier transform infrared spectroscopy. The results showed that the abundance of MaPs and MiPs ranged from 0.2 to 46.8 kg ha -1 , and 4.1 × 10 3 -3.7 × 10 4 items kg -1 , respectively. The prominent colors of the MaPs were white and black. The predominant shape, size and chemical composition of soil MiPs were fragments (45-62%), <1 mm (98-99%), and polyethylene (38-43%), respectively. MaPs were mainly detected in the 0-10 cm soil layer. MiP abundance in the 0-10 cm soil layer was significantly higher than that in the 20-30 cm soil layers among different farming systems, except for the fields with wheat-maize rotations and permanent orchards (p < 0.05). Overall, cotton fields showed the highest MaP and MiP abundance, followed by vegetable fields and orchards. Redundancy analysis revealed that tillage practices and plastic film management greatly influence the size distribution of MiPs. A strong negative correlation between large-sized plastic fractions (0.2-1 mm) and tillage frequency was tested while the years of application of plastic films and the abundance of plastic residues showed a strong positive correlation with small-sized plastic fractions (<0.2 mm). Our findings conclude that agricultural mulch films are an important source of MaPs and MiPs in agricultural soil and distributions are strongly influenced by agricultural management practices and farming systems. Further studies should take farming systems and farming practices into account, thereby exploring the potential mechanisms of plastic fragmentation and granularization in agricultural soil., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Mangroves serve a crucial role as metal accumulators in tropical and subtropical marine ecosystems, particularly in riverine mangroves, which frequently interact with terrestrial sources. In this study, we focused on the Gaoqiao and Jiuzhou Rivers within the Zhanjiang mangrove forest in Guangdong, China, and collected leaves and surface sediments from the dominant mangrove plant, Aegiceras corniculatum, near the riverbanks. We focused on seven heavy metals (Cr, Cu, Zn, As, Cd, Pb, and Hg) in mangrove leaves, surface sediments, and pore water due to their environmental significance and frequent occurrence in mangrove ecosystems. We employed multivariate statistical methods and pollution indicators to assess the potential sources and risk levels of heavy metals in these sediments. Our results reveal that the concentrations of the seven heavy metals in the sediments of the Gaoqiao and Jiuzhou Rivers varied significantly, ranging from 0.03 mg/kg to 100.00 mg/kg. Cd posed the highest ecological risk, followed by Hg and As. The comprehensive potential ecological risk in the Gaoqiao River was lower than that in the Jiuzhou River, likely due to the distribution of industrial enterprises (such as printing and cement plants) in the upper reaches of the Jiuzhou River. Additionally, the heavy metal content in the leaves of A. corniculatum and in pore water within surface sediments ranged from 0.01 to 51.58 mg/kg and 0.001 to 133.70 μg/L, respectively. A significant correlation was observed between the heavy metal concentrations in the A. corniculatum leaves and those in the pore water. Notably, the leaves of A. corniculatum exhibited a remarkable Hg-enrichment capability, highlighting its potential as a mercury accumulator. Most heavy metals in A. corniculatum leaves, pore water, and sediment were concentrated in the middle and upper reaches of the river, primarily due to anthropogenic terrestrial inputs from residential production activities upstream. Consequently, heavy metal pollution in riverine mangroves is primarily associated with human activities such as aquaculture, agricultural planting, and industrial production., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Benthic diatoms serve as exemplary indicators for the assessment of ecological conditions in freshwater ecosystems. However, an approach to assessing and managing transitional water zones by benthic diatoms is relatively less. This study entailed a detailed analysis and comparison of the seasonal dynamics in species- and guild-based benthic diatom communities and their driving factors in a small-scale transitional water zone of the Yellow River Delta. Our findings revealed substantial seasonal variations in the composition and abundance of dominant species, as well as in the α and β diversity of the species-based community. Temperature emerged as the predominant environmental factor driving significant seasonal variations in the species-based community. However, no significant seasonal changes were observed in the composition and relative abundance of dominant guilds, as well as in the α, β, and functional diversity of the guild-based community. Redundancy analysis and Mantel tests demonstrated the guild-based community exhibited a stronger correlation with environmental factors compared to the species-based community. The guild-based community exhibited resilience to the influence of seasonal temperature fluctuations and exhibited a strong correlation with phosphate concentration variations. Our findings suggest that the guild-based community is a feasible approach to assessing ecological status across various seasons in the transitional water zone of the Yellow River Delta., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Micropollutants have raised increasing concern due to their adverse effect on ecosystems and human health. So far, the effects of micropollutants in urban stormwater discharge on surface water quality or ecosystem health remains unclear. In this study, target and non-target screening methods were used to quantify and identify micropollutants in urban stormwater, wastewater, and surface water in humid regions of China. Results showed that the average concentration of micropollutants in surface waters in wet weather was 1.8 times that in dry weather. The cumulative concentrations of 143 micropollutants in samples from stormwater discharge were in the range of 490-1659 ng/L, which were comparable to or exceeded those from wastewater discharge. In terms of mass load in the studying area, stormwater discharges contained 10.8 kg of micropollutants in the month, a higher level compared to 4.58 kg in treated wastewater. Furthermore, the calculated risk quotients revealed medium to high ecological risk to aquatic organisms from substances such as telmisartan, irbesartan, 1,7-dimethylxanthine, and caffeine at ng/L concentrations, which are in typical levels in urban stormwater and surface waters in wet weathers. Our study reveals that urban stormwater discharge is an important pathway for micropollutants to surface waters, and urges for increased emphasis on, and reinforcement of, urban stormwater monitoring and control measures to minimize the transport of micropollutants to receiving waterbodies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Cyanobacterial Harmful Algal Bloom (CyanoHAB) is a global aquatic environmental issue, posing considerable eco-environmental challenges in freshwater lakes. Comprehensive monitoring and accurate prediction of CyanoHABs are essential for their scientific management. Nevertheless, traditional satellite-based monitoring and process-oriented prediction methods of CyanoHABs failed to satisfy this demand due to the limited spatiotemporal resolutions of both monitoring data and prediction results. To address this issue, this paper proposes an upgraded framework for comprehensive monitoring and accurate prediction of CyanoHABs. A collaborative CyanoHAB monitoring network was firstly constructed by integrating space, aerial, and ground-based monitoring means. As a result, CyanoHAB conditions were assessed frequently covering the entire lake, its key areas, and core positions. Furthermore, by overcoming technical limitations associated with high-precision simulation of the growth-drift-accumulation process of CyanoHABs, such as the unclear drifting process of CyanoHABs and the mechanism of its coastal accumulation, the multi-scale CyanoHAB prediction was realized interconnecting the entire lake and its nearshore areas. The implemented framework has been applied in Lake Chaohu for over three years. It provided high-frequency and high-spatial-resolution CyanoHAB monitoring, as well as its multi-scale and accurate simulation. The application of this framework in Lake Chaohu had significantly improved the accuracies of CyanoHAB monitoring, simulation, and early warning. This advancement holds significant scientific value and offers potential for CyanoHAB prevention and control in eutrophic lakes., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Yinguo Qiu reports financial support was provided by Nanjing Institute of Geography and LimnologyChinese Academy of Sciences. Yinguo Qiu reports a relationship with Nanjing Institute of Geography and Limnology Chinese Academy of Sciences that includes: employment. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

This study addressed the challenges of cost and portability in synchronous monitoring water quality and greenhouse gas emissions in paddy-dominated regions by developing a novel Internet of Things (IoT)-based monitoring system (WG-IoT-MS). The system, equipped with low-cost sensors and integrated intelligent algorithms, enabled real-time monitoring of dissolved N 2 O concentrations. Combined with an air-water gas exchange model, the system achieved efficient monitoring and simulation of CO 2 and N 2 O emissions from agricultural water bodies while reducing monitoring costs by approximately 60 %. The proposed method was validated in paddy-dominated regions in Danyang, China. Results indicated the excellence of the dissolved N 2 O concentration model based on support vector regression, demonstrating accurate predictions within a concentration range of 2.003 to 13.247 μg/L. Notably, the model maintained acceptable predictive accuracy (R 2 > 0.70) even when some variables were partially absent (with the number of missing variables < 2 and the missing proportion (MP) ≤ 50 %), making up for the data loss caused by sensor malfunctions. Furthermore, the model performed well (R 2 > 0.80) when testing data sourced from paddy fields and lakes. Finally, CO 2 and N 2 O emissions were successfully monitored, with the results validated using a floating chamber method (R 2 > 0.70). The method provides crucial technical support for quantitative assessment of water quality and greenhouse gas emissions in paddy-dominated regions, laying a foundation for formulating effective emission reduction strategies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Microplastics (MPs) pollution is ubiquitous, causing serious ecological damage by threatening the growth and health of living organisms. This study investigated the vertical and horizontal distribution of MPs, MPs-heavy metals (MPs-HMs) accumulation, contamination assessment and microbial biodiversity in hyporheic sediments of different land-use types. MPs abundance in shallow sediments (0-30 cm) was significantly higher than that in deep sediments (30-60 cm), with fewer large MPs in the deep sediments. Blue, fiber, and <500 μm were the dominant MPs types, and polystyrene, polylactic acid, and polyvinyl chloride were the dominant polymers in the Beiluo River Basin. The average concentrations of HMs detected in MPs were all much higher than the same metals in the sediments. The pollution loading index of MPs was higher in areas with a greater proportion of anthropogenic land use, and MP-HM were present to varying degrees in the vertical distribution (P N  > 1). Critically, bacterial diversity of anthropogenic land use was smaller than that of natural land use. High MP-HM concentrations reduced the abundance of cyanobacteria, nitrospirota, acidobacteriota, and planctomycetota, whereas desulfobacterota, chloroflexi, myxococcota, actinobacteriota, and proteobacteria have developed tolerance to MP-HM. Overall, our findings contribute to the understanding of the relationship between different land-use types and the spatial distribution of MPs and MP-HM, which is critical to manage and mitigate the hyporheic zone pollution., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Jinxi Song reports financial support was provided by National Natural Science Foundation of China. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Coastal oceans, serving as transitional zones between land and sea, possess unique geographical features and complex hydrological conditions, functioning as regional reservoirs and crucial transport pathways for anthropogenic pollutants such as per- and polyfluoroalkyl substances (PFASs) to the open ocean. This study comprehensively investigates traditional perfluoroalkyl carboxylic and sulphonic acids (PFCAs and PFSAs) and emerging perfluoroalkyl ether carboxylic and sulfonic acids (PFECAs and PFESAs), fluorotelomer sulfonates (FTSAs) in seawater columns and surface sediments from the inner shelf of the East China Sea, by integrating hydrological and biogeochemical data. Comparable levels of traditional and emerging PFASs were observed in seawater samples, in contrast to higher concentrations of traditional PFASs in surface sediments. Waterborne PFASs exhibited a nearshore-to-offshore decreasing trend and a surface enrichment pattern in offshore waters, typically influenced by terrestrial inputs and oceanic processes. Significant terrestrial inputs for waterborne PFASs were identified, including large rivers like the Changjiang River (Yangtze) and semi-enclosed coastal bays such as Xiangshan Port and Sanmen Bay, where prolonged hydraulic retention times contribute to PFAS accumulation. The source apportionment model demonstrated that emerging fluorochemical manufacturing, textile production, and high-performance fluoropolymer materials are primary sources, consistent with PFAS releases from commercial products and industrial processes along the Changjiang River and in Xiangshan County. Hydrologically, the offshore transport barrier effect created by river plume fronts, and the vertical stratification of different water masses were significant for PFASs. Sediment inputs and resuspension also played a crucial role, with surface sediment-bottom water partitioning behavior primarily regulated by the hydrophobicity of PFASs and salting-out effects. While the overall ecological risks of PFASs were low, elevated risks associated with legacy perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS), and emerging hexafluoropropylene oxide dimer acid (HFPO-DA) warrant closer attention due to their accumulation in the environment. The methodologies and findings of this research provide valuable insights into PFAS cycling in coastal oceans worldwide., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Wetlands are major microplastic sinks with a large atmospheric input. However, many details of such deposited atmospheric microplastics entering into wetlands remain unclear, including temporal patterns of input and ecological effects. We monitored the aerial microplastics during four seasons in eleven economically developed cities along the lower reaches of the Yangtze River Basin, China. The average microplastic deposition rate was 512.31 items m -2 d -1 , equivalent to an annual contribution of 17.46 metric tons of plastic to the surveyed wetlands with a total area of 1652 km 2 . These microplastics were predominantly composed of polyamide and polyethylene terephthalate with 61.85 ± 92.29 µm sized pellets, and we obtained similar results for microplastics intercepted on moss in wetlands. Microplastic input varied between wet and dry periods, primarily influenced by wind, rainfall and ozone concentration. Civilian vehicle density and textile industry were the primary socioeconomic factors driving microplastic deposition. Further indoor microcosm experiments revealed that moss phyllosphere bacterial community structure and function were influenced by microplastic abundance and size, exemplifying the unique ecological risks of aerially deposited microplastics to wetlands. These results indicate that mosses and their phyllosphere microbiota could serve as bio-indicators of aerial microplastic characteristics and impacts., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

This study investigated environmental distribution and human exposure of polycyclic aromatic hydrocarbons (PAHs) and their derivatives in one Chinese petroleum refinery facility. It was found that, following with high concentrations of 16 EPA PAHs (∑Parent-PAHs) in smelting subarea of studied petroleum refinery facility, total derivatives of PAHs [named as XPAHs, including nitro PAHs (NPAHs), chlorinated PAHs (Cl-PAHs), and brominated PAHs (Br-PAHs)] in gas (mean= 1.57 × 10 4 ng/m 3 ), total suspended particulate (TSP) (mean= 4.33 × 10 3 ng/m 3 ) and soil (mean= 4.37 × 10 3 ng/g) in this subarea had 1.76-6.19 times higher levels than those from other subareas of this facility, surrounding residential areas and reference areas, indicating that petroleum refining processes would lead apparent derivation of PAHs. Especially, compared with those in residential and reference areas, gas samples in the petrochemical areas had higher ∑NPAH/∑PAHs (mean=2.18), but lower ∑Cl-PAH/∑PAHs (mean=1.43 × 10 -1 ) and ∑Br-PAH/∑PAHs ratios (mean=7.49 × 10 -2 ), indicating the richer nitrification of PAHs than chlorination during petrochemical process. The occupational exposure to PAHs and XPAHs in this petroleum refinery facility were 24-343 times higher than non-occupational exposure, and the ILCR (1.04 × 10 -4 ) for petrochemical workers was considered to be potential high risk. Furthermore, one expanded high-resolution screening through GC Orbitrap/MS was performed for soils from petrochemical area, and another 35 PAHs were found, including alkyl-PAHs, phenyl-PAHs and other species, indicating that profiles and risks of PAHs analogs in petrochemical areas deserve further expanded investigation., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

China's lowland rural rivers are facing severe eutrophication problems due to excessive phosphorus (P) from anthropogenic activities. However, quantifying P dynamics in a lowland rural river is challenging due to its complex interaction with surrounding areas. A P dynamic model (River-P) was specifically designed for lowland rural rivers to address this challenge. This model was coupled with the Environmental Fluid Dynamics Code (EFDC) and the Phosphorus Dynamic Model for lowland Polder systems (PDP) to characterize P dynamics under the impact of dredging in a lowland rural river. Based on a two-year (2020-2021) dataset from a representative lowland rural river in the Lake Taihu Basin, China, the coupled model was calibrated and achieved a model performance (R 2 >0.59, RMSE<0.04 mg/L) for total P (TP) concentrations. Our research in the study river revealed that (1) the time scale for the effectiveness of sediment dredging for P control was ∼300 days, with an increase in P retention capacity by 74.8 kg/year and a decrease in TP concentrations of 23% after dredging. (2) Dredging significantly reduced P release from sediment by 98%, while increased P resuspension and settling capacities by 16% and 46%, respectively. (3) The sediment-water interface (SWI) plays a critical role in P transfer within the river, as resuspension accounts for 16% of TP imports, and settling accounts for 47% of TP exports. Given the large P retention capacity of lowland rural rivers, drainage ditches and ponds with macrophytes are promising approaches to enhance P retention capacity. Our study provides valuable insights for local environmental departments, allowing a comprehensive understanding of P dynamics in lowland rural rivers. This enable the evaluation of the efficacy of sediment dredging in P control and the implementation of corresponding P control measures., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

There have been reports of potential health risks for people from hydrophobic organic pollutants, such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated hydrocarbons (PCHs), and organophosphate flame retardants (OPFRs). When a contaminated site is used for residential housing or public utility and recreation areas, the soil-bound organic pollutants might pose a threat to human health. In this study, we investigated the contamination profiles and potential risks to human health of 15 PAHs, 6 PCHs, and 12 OPFRs in soils from four contaminated sites in China. We used an in vitro method to determine the oral bioaccessibility of soil pollutants. Total PAHs were found at concentrations ranging from 26.4 ng/g to 987 ng/g. PCHs (0.27‒14.3 ng/g) and OPFRs (6.30‒310 ng/g) were detected, but at low levels compared to earlier reports. The levels of PAHs, PCHs, and OPFRs released from contaminated soils into simulated gastrointestinal fluids ranged from 1.74% to 91.0%, 2.51% to 39.6%, and 1.37% to 96.9%, respectively. Based on both spiked and unspiked samples, we found that the oral bioaccessibility of pollutants was correlated with their logK ow and molecular weight, and the total organic carbon content and pH of soils. PAHs in 13 out of 38 contaminated soil samples posed potential high risks to children. When considering oral bioaccessibility, nine soils still posed potential risks, while the risks in the remaining soils became negligible. The contribution of this paper is that it corrects the health risk of soil-bound organic pollutants by detecting bioaccessibility in actual soils from different contaminated sites., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Heavy metal(loid) (HM) pollution in agricultural soils has become an environmental concern in antimony (Sb) mining areas. However, priority pollution sources identification and deep understanding of environmental risks of HMs face great challenges due to multiple and complex pollution sources coexist. Herein, an integrated approach was conducted to distinguish pollution sources and assess human health risk (HHR) and ecological risk (ER) in a typical Sb mining watershed in Southern China. This approach combines absolute principal component score-multiple linear regression (APCS-MLR) and positive matrix factorization (PMF) models with ER and HHR assessments. Four pollution sources were distinguished for both models, and APCS-MLR model was more accurate and plausible. Predominant HM concentration source was natural source (39.1%), followed by industrial and agricultural activities (23.0%), unknown sources (21.5%) and Sb mining and smelting activities (16.4%). Although natural source contributed the most to HM concentrations, it did not pose a significant ER. Industrial and agricultural activities predominantly contributed to ER, and attention should be paid to Cd and Sb. Sb mining and smelting activities were primary anthropogenic sources of HHR, particularly Sb and As contaminations. Considering ER and HHR assessments, Sb mining and smelting, and industrial and agricultural activities are critical sources, causing serious ecological and health threats. This study showed the advantages of multiple receptor model application in obtaining reliable source identification and providing better source-oriented risk assessments. HM pollution management, such as regulating mining and smelting and implementing soil remediation in polluted agricultural soils, is strongly recommended for protecting ecosystems and humans., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)