Natural coastal salt marshes are increasingly altered by invasion of the exotic plant Spartina alterniflora (SA) and subsequent reclamation into aquaculture ponds (AQ), forming a common transformation pathway from native vegetation to aquaculture systems. Such conversion may substantially modify nitrogen cycling and nitrous oxide (N2O) fluxes, however, the cascading impacts of these conversions and the relative contributions of key influencing factors, particularly the interplay among sediment physicochemical properties, dissolved organic matter (DOM), and microbial communities, remain poorly understood. To elucidate the mechanisms regulating N2O dynamics, we combined in situ flux monitoring with seasonal sediment sampling and anaerobic incubations across four representative wetland types along this transition sequence: mudflat (MF), mangrove (MG), SA marsh and AQ. The annual mean field N2O fluxes were 63.26 ± 60.46, 20.47 ± 11.97, 42.6 ± 41.25 and 2.23 ± 1.63 μg m-2 h-1 for MF, MG, SA and AQ, respectively, with differences among wetland types exceeding seasonal variability. The unexpectedly low fluxes from AQ were attributed to persistent inundation and reduced abundances of nitrification and denitrification genes, consistent with a lower microbial capacity for nitrogen transformation. Mantel tests and hierarchical partitioning revealed that sediment physicochemical and DOM characteristics provided the most consistent explanatory power across all four wetland types, whereas microbial influences were habitat dependent. Although AQ exhibited the lowest field N2O flux, structural equation modeling showed that DOM-microbe interactions were strongest in AQ, with DOM aromaticity, SOC, and TN identified as the most influential predictors. In AQ, environmental constraints likely make functional gene abundances a more proximate control of N2O emission than in tidally connected wetlands. Sediment anaerobic incubations, conducted under standardized laboratory conditions using unamended fresh sediments, revealed broadly similar N2O production potentials across wetland types. This laboratory result contrasts sharply with the large differences in field N2O fluxes, suggesting that vegetation structure and hydrological regime regulate the extent to which comparable microbial potentials are expressed under in situ conditions. Together with the multivariate analyses, our results show that sediment physicochemical properties and DOM composition are the strongest predictors of microbially mediated N2O emissions during the transformation of coastal wetlands from invasion to reclamation. This provides process-based evidence that coastal habitat conversion and aquaculture development can substantially alter N2O emission profiles, informing greenhouse-gas mitigation, nutrient management and ecological restoration in human-modified estuarine ecosystems.

ObjectiveEutrophication caused by nitrogen and phosphorus pollution is a major global environmental problem. However, understanding remains insufficient regarding the fine-scale spatial heterogeneity of pollution sources and the key driving factors of their spatial changes in large and medium-sized river basins, which hinders the formulation of targeted pollution control strategies.MethodsTo fill this gap, this study constructed a comprehensive analysis framework integrating remote sensing and hydrological analogy. We systematically analyzed the spatial distribution of nutrients in 60 subcatchments of the Jinjiang River Basin, identified high-pollution risk areas, and quantitatively analyzed the relative contributions of point sources (PS) and non-point sources (NPS).ResultsThe results show that: (1) Nitrogen and phosphorus pollution are widespread throughout the basin, with nitrogen pollution being particularly prominent. 48.3% of monitoring sections in the rainy season and 33.3% in the dry season have nutrient concentrations exceeding the threshold for algae reproduction, posing significant eutrophication risks. (2) Farmland and urban land are the main sources of total nitrogen (TN) and total phosphorus (TP). Farmland NPS pollution accounts for 43.2% of the TN load. Urban land (PS) is the primary source of TP load, accounting for 38.4% of the contribution. (3) High-pollution risk areas are mainly concentrated in three core regions: the downstream urban corridor, the Nan'an Industrial Zone, and the upstream tea garden area.ConclusionsBased on these results, targeted measures are proposed: upgrading urban wastewater treatment facilities, implementing stricter industrial discharge standards, and promoting sustainable agricultural practices in farmland and tea gardens. The spatial priority identification method developed in this study provides a scientific, reliable, and replicable basis for determining priority intervention areas in similar river basins.

To address the deficiencies in comprehensive surface contamination prevention strategies within China's nitrate-affected regions, this research innovatively proposes the DITAPH model-a systematic framework integrating groundwater nitrate vulnerability assessment and Nitrate Vulnerable Zones (NVZs) delineation through optimization of hydrogeological parameters. Based on detailed hydrogeological and hydrochemical investigations, the DITAPH model was applied in the plain areas of Quanzhou to evaluate its applicability. The model selected hydrogeological parameters (depth of groundwater, lithology of the vadose zone, topographic slope, aquifer water yield property), one climatic parameter (precipitation), and two anthropogenic parameters (land use type and population density) as assessment indicators. The results of the groundwater nitrate vulnerability assessment showed that the low, relatively low, relatively high, and high groundwater nitrate vulnerability zones in the study area accounted for 5.96%, 35.44%, 53.74% and 4.86% of the total area, respectively. Groundwater nitrate vulnerability was most strongly influenced by human activities, followed by groundwater depth and topographic slope. The high vulnerability zone is mainly affected by domestic and industrial wastewater, whereas the relatively high groundwater nitrate vulnerability zone is primarily influenced by agricultural activities. Validation of the DITAPH model revealed a significant positive correlation between the DITAPH index (DI) and nitrate concentration (rho(NO3-)). The results of the NVZs delineated by the DITAPH model are reliable and can serve as a tool for water resource management planning, guiding the development of targeted measures in the NVZs to prevent groundwater contamination.

Coastal wetlands have high carbon sequestration potential, and microorganisms are essential in soil carbon cycling. With the increasing degradation of coastal wetlands, ecological restoration has been widely applied to improve wetland functions; however, its regulatory effects on carbon pools and microbial carbon cycling remain unclear. The effects of three ecological restoration strategies in the Bohai Bay coastal zone-Suaeda salsa restoration (SR), Spartina alterniflora cutting (SC), and Zostera marina seagrass planting (SP)-on wetland carbon pool compositions and key environmental factors were examined, and metagenomic sequencing was used to characterize the carbon cycling functions in restored soils. The restoration strategies affected active organic carbon pools: the dissolved organic carbon and microbial biomass carbon contents decreased under SR and SP, respectively, but increased under SC. Strategy-specific changes in soil redox conditions and active organic carbon pools were closely linked to shifts in microbial carbon fixation pathways and organic carbon degradation functions. SR reduced the relative contributions of four pathways to carbon fixation (reductive tricarboxylic acid (rTCA) cycle, dicarboxylate/4-hydroxybutyrate (DC/4-HB) cycle, Calvin-Benson-Bassham (CBB) cycle, Wood-Ljungdahl (W-L) pathway) and SC enhanced the relative contribution of W-L pathway but decreased those of the 3-hydroxypropionate (3-HP) and CBB cycles. SR inhibited starch, hemicellulose, cellulose, and chitin degradation, and SC enhanced chitin degradation. SP had limited effects on either process. Ecological restoration altered the abundance of key carbon cycling microbial taxa (Pseudomonadota, Thermodesulfobacteriota, and Chloroflexota), influencing microbial carbon cycling functions in soil. From a management perspective, Spartina alterniflora cutting is an effective strategy for enhancing soil active organic carbon storage and microbial capacity for organic carbon turnover in coastal wetlands, whereas Suaeda salsa restoration is better suited to strengthening organic carbon stability and conserving existing stocks. These findings elucidate the mechanisms by which ecological restoration regulates microbial carbon cycling by altering soil conditions and provide a basis for enhancing carbon sequestration and optimizing restoration strategies for coastal wetlands.

Anomalous enrichment of geogenic fluoride and iodine in groundwater has become a major geogenic environmental concern in the Heilonggang Basin of the eastern North China Plain. In this study, 353 deep groundwater samples were collected to assess groundwater quality and human exposure risks. Piper diagrams, inverse distance weighting interpolation, the entropy-weighted water quality index (EWQI), the US Environmental Protection Agency human health risk assessment (HHRA) framework, and Monte Carlo simulation (MCS) were integrated to evaluate the health risks associated with F- and I- exposure. Groundwater pH ranged from 6.40 to 8.99, and the groundwater was generally weakly alkaline. Na-Cl was the dominant hydrochemical facies. I- concentrations ranged from below the detection limit to 0.96 mg/L, while F- concentrations ranged from 0.42 to 8.14 mg/L. Both constituents were markedly enriched in the eastern coastal area of Cangzhou. The EWQI assessment indicated that only 47.8% of the samples were classified as having excellent or good water quality. Poorer groundwater quality was mainly observed in the eastern coastal zone. The estimated health risk from drinking-water ingestion was substantially higher than that from dermal contact. For fluoride exposure, the mean hazard index (HI) exceeded the acceptable threshold for adults, children, and infants across the study area. Monte Carlo sensitivity analysis further showed that exposure concentration was the primary determinant of health risk, accounting for 68.7%-68.9% of the total variance. Infants and young children were particularly susceptible to exposure. These findings demonstrate that deep groundwater in the eastern Heilonggang Basin poses potential health risks due to elevated fluoride and iodide levels. The results provide a scientific basis for groundwater management and for preventing endemic diseases in comparable groundwater systems across the North China Plain.

The occurrence of emerging pollutants (EPs) in aquatic environments is a major threat to natural ecosystems and human health, but the connections between EPs in surface water and groundwater have been largely unexplored. Here, a total of 38 EPs, including antibiotics, per- and poly-fluorinated alkyl substances, and herbicides were monitored in both surface water and adjacent groundwater in the Jiulong River Basin of China. Thirteen different EPs were detected, with atrazine, sulfamethoxazole and perfluorooctanoic acid identified as priority pollutants based on a novel holistic scoring method that integrated concentration levels, occurrence frequency, and environmental and human health risks in surface water-groundwater systems. Clear connections between the EPs in surface water and groundwater were apparent, demonstrated through principal component analysis and hierarchical clustering. Agricultural activities appear to be the main EP sources, with dissolved oxygen playing a significant role in the occurrence of EPs in both surface water and groundwater. The detected EPs can be well explained by the interaction between surface water and groundwater in combination with natural attenuation processes. These findings underscore the critical role of surface water-groundwater exchange in the fate of EPs within water systems, a factor often overlooked in prior EP analyses.

Identifying the drivers and threats to coastal groundwater quality has emerged as one of the critical environmental and resource management issues. In this study, 140 shallow groundwater samples were collected from the coastal plain of Quanzhou City in China. Methods applied included mathematical statistics, correlation analysis, ionic ratio, isotope techniques, hydrochemical facies evolution diagrams (HFE-D), entropy weight water quality index (EWQI), health risk evaluation model and Monte Carlo simulation. The results demonstrated that the groundwater in the study area was neutral to weakly acidic, mainly soft water and fresh water. The groundwater chemical types were mainly composed of Cl-Na (37.86%), HCO3-Ca-Na (32.14%) and HCO3-Ca (27.86%). The natural sources of groundwater chemical composition were mainly controlled by the rock weathering, evaporation and cation exchange action. Nitrate with relatively high content in groundwater was found to originate mainly from anthropogenic inputs including domestic sewage and agricultural activities. The results of the stable isotope analysis showed the contributions of potential nitrate sources were 66.6%, 21.5%, 15.0%, and 2.5% for sewage and manure, soil nitrogen, synthetic fertilizer, and atmospheric deposition, respectively. The results of EWQI indicated that the overall groundwater quality of this study area was relatively good and suitable for domestic use. However, health risk evaluation based on Monte Carlo simulation showed that the probabilities of non-carcinogenic risk from groundwater nitrate were 4.31% for males, 5.71% for females, 13.93% for children and 25.80% for infants, respectively. The intake of high nitrate content groundwater via drinking pathway would pose a threat to the health of the local residents and require attention.

In recent years,the Nandagang wetland in Hebei Province has been facing a multidimensional water environmental crisis characterized by decreasing water volume,deteriorating water quality,and declining ecological service functions.Analyzing the sources and causes of major ions is crucial for improving the wetland's aquatic ecological environment.Samples of river water,lake water,seawater,and groundwater in the Nandagang wetland,Cangzhou City,Hebei Province,were analyzed.Comprehensive methods,including mathematical statistics,correlation analysis,ion ratios,and the positive matrix factorization(PMF)model,were employed to analyze the hydrochemical characteristics and formation mechanisms of different water bodies.The results indicate:(1)River water,lake water,groundwater,and seawater in the study area are all weakly alkaline Cl-Na type water.(2)The water bodies in the study area are strongly controlled by evaporation and concentration.From inland to coastal areas,the total dissolved solids(TDS)content in river water and groundwater gradually increases,and evaporation intensifies.(3)From the recharge area to the discharge area,the HCO3-/C1-ratio in groundwater gradually decreases.The main ions in shallow groundwater originate from seawater.Evaporation exacerbates groundwater salinization,while cation exchange is a secondary factor.The weakly alkaline hydrochemical environment facilitates ion enrichment.Human activities such as agricultural fertilization in the groundwater recharge area and livestock farming in the groundwater stagnant zone are anthropogenic factors influencing groundwater chemical composition.The main ions in the study area'lake water originate from the northern salt fields,with ecological water replenishment being the secondary source.Petrochemical plants are a potential factor affecting the lake water's chemical composition.The exceedance rates of NO3-concentration standards for river water,lake water,and groundwater samples in the study area were 37.5％,8.3％,and 37.5％,respectively.Key factors causing groundwater exceedance include agricultural fertilization,animal manure,and seawater mixing.It is recommended to control human activities such as agricultural fertilization and aquaculture to reduce the nitrate load in the regional water bodies.The BRIEF REPORT is available for this paper at .

Coastal estuaries are increasingly impacted by anthropogenic nitrogen inputs, disrupting nitrogen cycling and posing significant threats to ecosystem health. This study investigates nitrogen sources and transformation processes in the Jiulong River Estuary (JRE), a highly eutrophic subtropical estuary in Southeast China. By analyzing and comparing samples from groundwater, surface water, and sediment, this study reveals distinct nitrogen transformation dynamics across interconnected environmental compartments. A comprehensive framework integrating stable isotope analysis, sediment incubation experiments, and microbial molecular techniques was employed to characterize nitrogen dynamics both regionally and at the sediment-water interface within diverse wetland types. Manure and sewage were identified as the primary nitrogen sources. Salinity emerged as a key regulator of nitrogen transformations, with freshwater wetlands exhibiting the highest denitrification potential, followed by mudflats, aquaculture ponds, and mangroves. Abiotic factors, including hydrological conditions and wetland types, were found to predominantly drive nitrogen transformations, while biotic factors, such as microbial community composition and functional gene abundances, played a secondary but interconnected role under the influence of abiotic drivers. These findings offer valuable insights into nitrogen cycling in estuarine ecosystems and propose a robust framework for mitigating nitrogen pollution and managing eutrophication in coastal regions.

Groundwater is the critical resource for agricultural, industrial, and urban–rural water supplies in arid and semi-arid regions, especially in North China Plain. In this study, 64 groundwater samples were collected to assess the potential for groundwater development and utilization in the upper reaches of the Zhang Wei river. The hydrochemical analysis revealed that the groundwater is primarily composed of HCO3-Ca and HCO3-Na·Ca. The hydrochemical type is influenced by natural water–rock interactions, including evaporite dissolution, silicate weathering, and ion exchange processes. Isotope data for hydrogen and oxygen, characterized by positive deviations from the global meteoric water line, underscore the significant impact of evaporation in the region. An entropy weight index method was employed for water quality evaluation, revealing that over 89

Sub-surface sediments in freshwater wetlands function as active habitats for microbial denitrifying anaerobic methane oxidation (DAMO) processes and as hotspots for antibiotic accumulation. Focusing on the Baiyangdian wetland, which is contaminated with quinolone antibiotics (QNs) and hosts active DAMO processes, this study employed 13C-labeled microcosm incubation experiments, RT-qPCR, and gene sequencing to decipher the response mechanisms of DAMO processes to prevalent QNs in the sub-surface sediments (0.5 20 cm) of study area. Short-term exposure (24 h) to typical QNs at 200 ng·g-1 reduced nitrite-DAMO activities by approximately 33 %, primarily through selective inhibition of antibiotic-sensitive species within NC10 bacteria. In contrast, exposure to the same concentration of QNs enhanced nitrate-DAMO activities by about 450 %, likely due to hormetic stimulation of antibiotic-resistant ANME-2d archaea, combined with the inhibition of substrate competitor. Long-term exposure (90 days) to typical QNs mitigated these effects as bacterial adaptation to antibiotics occurred, resulting in a time-dependent attenuation of their impacts. This study underscores the significance of DAMO processes as methane sinks in changing environments and broadens the understanding of the ecological risks posed by antibiotics.

Our study examines nitrogen sources and transformations in Xiamen Bay, where eutrophication has increased due to higher nitrogen levels. By analyzing dissolved organic matter (DOM) and nitrate stable isotopes (515N- NO3-and 518O-NO3-), the study finds that nitrate in low salinity areas is influenced by freshwater-seawater mixing and biogeochemical processes, while in high salinity areas, it is mainly affected by physical mixing. Bayesian mixing model (MixSIAR) results show that the primary nitrate sources are fecal matter and sewage, followed by atmospheric deposition. During the high flow period, DOM may facilitate nitrogen transformation and release through processes such as degradation or mineralization. In contrast, during the low flow period, the system is mainly influenced by the physical mixing of saline and freshwater. Studies have shown that DOM can indicate the biogeochemical intensity in water bodies, further identifying the main factors influencing the distribution and transformation processes of nitrate content, providing a basis for mitigating eutrophication in estuarine areas.

Methane, the most significant reduced form of carbon on Earth, acts as a crucial fuel and greenhouse gas. Globally, microbial methane sinks encompass both aerobic oxidation of methane (AeOM), conducted by oxygen-utilizing methanotrophs, and anaerobic oxidation of methane (AOM), performed by anaerobic methanotrophs employing various alternative electron acceptors. These electron acceptors involved in AOM include sulfate, nitrate/nitrite, humic substances, and diverse metal oxides. The known anaerobic methanotrophic pathways comprise the internal aerobic oxidation pathway found in NC10 bacteria and the reverse methanogenesis pathway utilized by anaerobic methanotrophic archaea (ANME). Diverse anaerobic methanotrophs can perform AOM independently or in cooperation with symbiotic partners through several extracellular electron transfer (EET) pathways. AOM has been documented in various environments, including seafloor methane seepages, coastal wetlands, freshwater lakes, soils, and even extreme environments like hydrothermal vents. The environmental activities of AOM processes, driven by different electron acceptors, primarily depend on the energy yields, availability of electron acceptors, and environmental adaptability of methanotrophs. It has been suggested that different electron acceptors driving AOM may occur across a wider range of habitats than previously recognized. Additionally, it is proposed that methanotrophs have evolved flexible metabolic strategies to adapt to complex environmental conditions. This review primarily focuses on AOM, driven by different electron acceptors, discussing the associated reaction mechanisms and the habitats where these processes are active. Furthermore, it emphasizes the pivotal role of AOM in mitigating methane emissions.

An ecological security pattern is an essential natural solution for promoting the coordinated and sustainable development of urban growth and the ecological environment within a given region. This study aims to develop a comprehensive ecological security pattern (ESP) for the Jinjiang watershed by integrating multiple ecological service functions: ecological regulation, eco-product provisions, and human settlement services. Using a well-established methodology of “source identification—resistance surface construction—ecological corridor extraction”, we identified 322 ecological source areas and delineated 321 ecological corridors spanning 1941.67 km, with key corridors connecting ecological regulation sources and ordinary corridors primarily linking eco-product provisions and human settlement sources. Our results show that the northern hilly regions are significant for ecological regulation, Anxi County is key for eco-product provisions, and human settlement services are scattered across urban areas and river valleys. This integration enhances regional ecological sustainability and provides a model for similar coastal regions globally. Our findings offer scientific guidance for balancing urban growth with ecological preservation, contributing to sustainable development worldwide.

Groundwater is an important source of drinking water. Groundwater pollution severely endangers drinking water safety and sustainable social development. In the case of groundwater pollution, the top priority is to identify pollution sources, and accurate information on pollution sources is the premise of efficient remediation. Then, an appropriate pollution remediation scheme should be developed according to information on pollution sources, site conditions, and economic costs. The methods for identifying pollution sources mainly include geophysical exploration, geochemistry, isotopic tracing, and numerical modeling. Among these identification methods, only the numerical modeling can recognize various information on pollution sources, while other methods can only identify a certain aspect of pollution sources. The remediation technologies of groundwater can be divided into in-situ and ex-situ remediation technologies according to the remediation location. The in-situ remediation technologies enjoy low costs and a wide remediation range, but their remediation performance is prone to be affected by environmental conditions and cause secondary pollution. The ex-situ remediation technologies boast high remediation efficiency, high processing capacity, and high treatment concentration but suffer high costs. Different methods for pollution source identification and remediation technologies are applicable to different conditions. To achieve the expected identification and remediation results, it is feasible to combine several methods and technologies according to the actual hydrogeological conditions of contaminated sites and the nature of pollutants. Additionally, detailed knowledge about the hydrogeological conditions and stratigraphic structure of the contaminated site is the basis of all work regardless of the adopted identification methods or remediation technologies.

A pilot project for groundwater recharge from rivers is currently being carried out in North China Plain. To investigate the influence of river recharge on groundwater hydrochemical characteristics, dynamic monitoring and analysis of groundwater samples were conducted at a typical recharge site in the Hutuo River alluvial-pluvial fan in the North China Plain from 2019 to 2021. Hydrochemical, isotopic, and multivariate statistical analyses were used to systematically reveal the spatiotemporal variation of groundwater chemistry and its driving factors during groundwater recharge process. The results showed that the groundwater hydrochemical types and characteristics in different recharge areas and recharge periods exhibited obvious spatiotemporal differences. The groundwater type varied from HCO3·SO4-Na·Mg to HCO3·SO4-Ca·Mg in an upstream ecological area, while the groundwater type changed from SO4·HCO3-Mg·Ca to HCO3·SO4-Ca·Mg in the downstream impacted by reclaimed water. Changes in the contents of Ca2+, Mg2+ and HCO3- were mostly controlled by the water-rock interactions and mixing-dilution of recharge water, while the increases in Na+, NO3-, Cl-, SO42- and NO3- contents were mainly due to the infiltration of reclaimed water. Nitrogen and oxygen isotope (δ15N and δ18O) tests and the Bayesian isotope mixing model results further demonstrated that nitrate pollution mainly originated from anthropogenic sources, and the major contribution came from manure and sewage, with an average proportion of 64.6 %. Principal component analysis indicated that water-rock interactions, river-groundwater mixing and redox environment alternation were dominant factors controlling groundwater chemical evolution in groundwater recharge process.

Roxarsone (ROX), commonly employed as a livestock feed additive, largely remains unmetabolized and is subsequently excreted via feces. ROX could cause serious environmental risks due to its rapid transformation and high mobility in the anaerobic subsurface environment. Dissolved organic matter (DOM) is an important constituent of fecal organics in livestock waste and could affect the ROX biotransformation. Nonetheless, the underlying mechanisms governing the interaction between DOM and ROX biotransformation have not yet been elucidated in the anaerobic environment. In this study, the changes of ROX, metabolites, and microbial biomass in the solutions with varying DOM concentrations (0, 50, 100, 200, and 400 mg/L) under anaerobic environments were investigated during the ROX (200 mg/L) degradation. EEM-PARAFAC and metagenomic sequencing were combined to identify the dynamic shifts of DOM components and the functional microbial populations responsible for ROX degradation. Results indicated that DOM facilitated the anaerobic biotransformation of ROX and 200 mg/L ROX could be degraded completely in 28 h. The tryptophan-like within DOM functioned as a carbon source to promote the growth of microorganisms, thus accelerating the degradation of ROX. The mixed microflora involved in ROX anaerobic degrading contained genes associated with arsenic metabolism (arsR, arsC, acr3, arsA, nfnB, and arsB), and arsR, arsC, acr3 exhibited high microbial diversity. Variations in DOM concentrations significantly impacted the population dynamics of microorganisms involved in arsenic metabolism (Proteiniclasticum, Exiguobacterium, Clostridium, Proteiniphilum, Alkaliphilus, and Corynebacterium spp.), which in turn affected the transformation of ROX and its derivatives. This study reveals the mechanism of ROX degradation influenced by the varying concentrations of DOM under anaerobic environments, which is important for the prevention of arsenic contamination with elevated levels of organic matter.

Multi-media environmental distribution of 21 pharmaceuticals in river water, coastal water, groundwater and sediments from the Jin River to adjacent marine embayment, Southeast China, was reported for the first time. All the detected 10 pharmaceuticals were antibiotics. Oxytetracycline (OTC), ciprofloxacin (CFC) and enrofloxacin (EFC) were the most ubiquitous antibiotics and could be detected in all water samples. EFC also showed the highest detection frequency (100%) in both riverine and coastal sediments. The detected antibiotics were more widely distributed in coastal environment of Asia, especially China, rather than Europe, USA and Australia. Sulfamethoxazole (SMX) showed stronger sorption onto sediments compared with other antibiotics due to its higher pseudo-partitioning coefficients (846-10,786 L kg-1). The discharged wastewater and aquaculture were the main sources of antibiotics in the multi-media environment. Risk assessment indicated that CFC and SMX posed high risks to Microcystis aeruginosa and Synechococcus leopolensis in river water, coastal water and groundwater.

In order to further clarify the groundwater pollution risk of the pharmaceutical and personal care products（PPCPs）, also known as emerging organic contaminants, in land application of sludge, groundwater pollution risks of 29 PPCPs under sand and loam soil conditions are primarily evaluated using a mathematical model. The results show that ciprofloxacin, ofloxacin, oxytetracycline, norfloxacin and caffeine have risk index values higher than 1 under sand soil conditions, indicating high groundwater pollution risks. Except caffeine, all the other 4 PPCPs with high groundwater pollution risks are antibiotics, which need to be further monitored and controlled in groundwater. Under loam soil conditions, all the 29 PPCPs show low groundwater pollution risks.Sorption is the main factor affecting the groundwater pollution risk of PPCPs. Sensitivity analyses indicate that the half-life of PPCPs in soil, organic carbon partition coefficient, soil density, organic carbon content and depth of the zone with organic matter are the key parameters affecting the model output. Uncertainty analyses show that changes in the organic carbon partition coefficient and half-life of PPCPs in soil have great impact on groundwater pollution risks. Test and verification show that PPCPs with higher groundwater pollution risk index values had higher detection rates in groundwater, indicating that the evaluation results are reliable. Further researches on degradation products of PPCPs, their safe levels in groundwater, interactions between coexisting PPCPs and medium heterogeneity effects should be strengthened in order to evaluate the groundwater pollution risk of PPCPs with reasonable accuracy.