Improved Approaches to Calculating Dilution and Attenuation Factor in Contaminant Hydrogeology

Dilution and attenuation factor (DAF) has a major influence on soil-to-groundwater screening level calculation for protection of contaminant migration from soil into groundwater at solid waste management units (SWMUs). Risk assessment guidance prepared by U.S. Environmental Protection Agency for site investigation and remediation suggests a default DAF of 20. If the base assumptions included in the default DAF are recognized to be not representative of site conditions at a SWMU, calculation of site-specific DAF is recommended when sufficient data are collected to justify using a different DAF value for development of soil screening levels. Commonly used methods of calculating DAF include analytical and numerical simulations that often require too many parameters to be obtained in practice. This paper proposes a probability method to develop site-specific DAF. The approach uses data that are readily available through field reconnaissance and site-specific investigation. A case study is presented in which the probability method was applied to an actual SWMU, and the calculated DAF is compared with that calculated from a dilution method. The probability-based DAF is 67 at 90% probability percentile, which is comparable to the dilution-based DAF of 76. Based on the calculated site-specific DAFs, SSLs could be developed for the contaminants of potential concern and used for evaluation of migration pathways from a contamination source through soil to groundwater. .

Planning and construction of Xiong’an New Area(city of over 5 million people):Contributions of China’s geologists and urban geology

China established Xiong’an New Area in Hebei Province in 2017,which is planned to accommodate about 5 million people,aiming to relieve Beijing City of the functions non-essential to its role as China’s capital and to expedite the coordinated development of the Beijing-Tianjin-Hebei region.From 2017 to 2021,the China Geological Survey(CGS)took the lead in multi-factor urban geological surveys involving space,resources,environments,and disasters according to the general requirements of“global vision,international standards,distinctive Chinese features,and future-oriented goals”in Xiong’an New Area,identifying the engineering geologic conditions and geologic environmental challenges of this area.The achievements also include a 3D engineering geological structure model for the whole area,along with“one city proper and five clusters”,insights into the ecology and the background endowment of natural resources like land,geothermal resources,groundwater,and wetland of the area before engineering construction,a comprehensive monitoring network of resources and environments in the area,and the“Transparent Xiong’an”geological information platform that is open,shared,dynamically updated,and three-dimensionally visualized.China’s geologists and urban geology have played a significant role in the urban planning and construction of Xiong’an New Area,providing whole-process geological solutions for urban planning,construction,operation and management.The future urban construction of Xiong’an New Area will necessitate the theoretical and technical support of earth system science(ESS)from various aspects,and the purpose is to enhance the resilience of the new type of city and to provide support for the green,low-carbon,and sustainable development of this area.

Groundwater and environmental challenges in Asia

Asia stands out as the most populous and geographically diverse region globally.The pressing issues of water resource development and the resulting ecological impacts are exacerbated by the region's rapid population growth and economic expansion.Groundwater,a vital source of water in Asia,faces significant disparities in distribution and suffers from unsustainable exploitation practices.This study applies groundwater system theory and categorizes Asia into 11 primary groundwater systems and 36 secondary ones,based on intercontinental geological structures,climate,terrain,and hydrogeological characteristics.As of the end of 2010,Asia's assessed groundwater resources totalled 4.677×10^(9) m^(3)/a,with exploitable resources amounting to 3.274×10^(9) m^(3)/a.By considering the geological environmental impacts of groundwater development and the distinctive characteristics of terrain and landforms,six categories of effect zones with varying distribution patterns are identified.The current research on Asia's groundwater resources,environmental dynamics,and human impacts aims to provide a theoretical foundation for sustainable groundwater management and environmental conservation in the region.

Microbial community composition and environmental response characteristics of typical brackish groundwater in the North China Plain

To reveal the microbial community composition of regional shallow porous brackish groundwater and its response characteristics to groundwater environment,the first and second aquifers in Taocheng District,Hengshui City were selected,and 10 groundwater source samples were collected for hydrochemical analysis and microbial 16S RNA gene V4-V5 regional sequencing.The results showed that the shallow brackish groundwater in the study area is weakly alkaline and has high ion content.The hydrochemical types are SO_(4)·Cl-Na·Mg type and HCO3·Cl-Na·Mg type as a whole.The spatial zonation of the abundance and diversity of groundwater microorganisms is obvious.The number of endemic bacteria in groundwater from upstream,midstream to downstream is 11,135 and 22 respectively,with a total of 22 bacteria.Proteobacteria is the most dominant in groundwater level(38.82%-86.88%),and there are obvious differences in different sections.At the genus level,the main dominant species in each group and sample are Pseudomonas and Hydrogenophaga.In terms of composition difference,Pseudohongiella,Pseudorhodobacter and Limnohabitans are the representatives of UR,MR and LR.On the whole,the composition of flora in groundwater in the study area is sensitive and closely related to hydrochemical processes.Species abundance is affected by alkaline and high salinity environmental indicators,while species diversity is related to depth and dissolved oxygen in weak reduction environment.

Development status and prospect of underground thermal energy storage technology

Underground Thermal Energy Storage(UTES)store unstable and non-continuous energy underground,releasing stable heat energy on demand.This effectively improve energy utilization and optimize energy allocation.As UTES technology advances,accommodating greater depth,higher temperature and multi-energy complementarity,new research challenges emerge.This paper comprehensively provides a systematic summary of the current research status of UTES.It categorized different types of UTES systems,analyzes the applicability of key technologies of UTES,and evaluate their economic and environmental benefits.Moreover,this paper identifies existing issues with UTES,such as injection blockage,wellbore scaling and corrosion,seepage and heat transfer in cracks,etc.It suggests deepening the research on blockage formation mechanism and plugging prevention technology,improving the study of anticorrosive materials and water treatment technology,and enhancing the investigation of reservoir fracture network characterization technology and seepage heat transfer.These recommendations serve as valuable references for promoting the high-quality development of UTES.

Pollution source identification methods and remediation technologies of groundwater: A review

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.

Two stages power generation test of the hot dry rock exploration and production demonstration project in the Gonghe Basin,northeastern Qinghai-Tibet plateau,China

The Hot Dry Rock(HDR)is considered as a clean and renewable energy,poised to significantly contribute to the global energy decarbonization agenda.Many HDR projects worldwide have accumulated valuable experience in efficient drilling and completion,reservoir construction,and fracture simulation.In 2019,China Geological Survey(CGS)initiated a demonstration project of HDR exploration and production in the Gonghe Basin,aiming to overcome the setbacks faced by HDR projects.Over the ensuing four years,the Gonghe HDR project achieved the first power generation in 2021,followed by the second power generation test in 2022.After establishing the primary well group in the initial phase,two directional wells and one branch well were drilled.Noteworthy progress was made in successfully constructing the targeted reservoir,realizing inter-well connectivity,power generation and grid connection,implementing of the real-time micro-seismic monitoring.A closed-loop technical validation of the HDR exploration and production was completed.However,many technical challenges remain in the process of HDR industrialization,such as reservoir fracture network characterization,efficient drilling and completion,multiple fracturing treatment,continuous injection and production,as well as mitigation of induced seismicity and numerical simulation technology.

Clogging caused by coupled grain migration and compaction effect during groundwater recharge for unconsolidated sandstone reservoir in groundwater-source heat pump

In unconsolidated sandstone reservoirs,presence of numerous movable grains and a complex grain size composition necessitates a clear understanding of the physical clogging process for effective groundwater recharge in groundwater-source heat pump systems.To investigate this,a series of seepage experiments was conducted under in situ stress conditions using unconsolidated sandstone samples with varying grain compositions.The clogging phenomenon arises from the combined effects of grain migration and compaction,wherein the migration of both original and secondary crushed fine-grain particles blocks the seepage channels.Notably,grain composition influences the migration and transport properties of the grains.For samples composed of smaller grains,the apparent permeability demonstrates a transition from stability to decrease.In contrast,samples with larger grains experience a skip at the stability stage and directly enter the decrease stage,with a minor exception of a slight increase observed.Furthermore,a unique failure mode characterized by diameter shrinkage in the upper part of the sample is observed due to the combined effects of grain migration and in situ stress-induced compaction.These testing results contribute to a better understanding of the clogging mechanism caused by the coupled effects of grain migration and compaction during groundwater recharge in unconsolidated sandstone reservoirs used in groundwater-source heat pump systems.

Optimization of water-urban-agricultural-ecological land use pattern:A case study of Guanzhong Basin in the southern Loess Plateau of Shaanxi Province,China

Extensive land use will cause many environmental problems.It is an urgent task to improve land use efficiency and optimize land use patterns.In recent years,due to the flow decrease,the Guanzhong Basin in Shaanxi Province is confronted with the problem of insufficient water resources reserve.Based on the Coupled Ground-Water and Surface-Water Flow Model(GSFLOW),this paper evaluates the response of water resources in the basin to changes in land use patterns,optimizes the land use pattern,improves the ecological and economic benefits,and the efficiency of various spatial development,providing a reference for ecological protection and high-quality development of the Yellow River Basin.The research shows that the land use pattern in the Guanzhong Basin should be further optimized.Under the condition of considering ecological and economic development,the percentage change of the optimum area of farmland,forest,grassland,water area,and urban area compared with the current land use area ratio is+2.3,+2.4,-6.1,+0.2,and+1.6,respectively.The economic and ecological value of land increases by14.1%and 3.1%,respectively,and the number of water resources can increase by 2.5%.

Temporal and spatial variations hydrochemical components and driving factors in Baiyangdian Lake in the Northern Plain of China

Understanding the temporal and spatial variation of hydrochemical components in large freshwater lakes is crucial for effective management and conversation.In this study,we identify the temporalspatial characteristics and driving factors of the hydrochemical components in Baiyangdian Lake using geochemical methods(Gibbs diagram,Piper diagram and End-element diagram of ion ratio)and multivariate statistical techniques(Principal component analysis and Correlation analysis).16 sets of samples were collected from Baiyangdian Lake in May(normal season),July(flood season),and December(dry season)of 2022.Results indicate significant spatial variation in Nat,ci,SO and NO,,suggesting a strong influence of human activities.Cation concentrations exhibit greater seasonal variation in the dry season compared to the flood season,while the concentrations of the four anions show inconsistent seasonal changes due to the combined effects of river water chemical composition and human activities.The hydrochemical type of Baiyangdian Lake is primarily HCO,Cl-Na.Ca,Mg*and HCO,originate mainly from silicate and carbonate rock dissolution,while Kt,Nat and CI originate mainly from sewage and salt dissolution in sediments.SO42 may mainly stem from industrial wastewater,while NO,primarily originates from animal feces and domestic sewage.Through the use of Principal Component Analysis,it is identified that water-rock interaction(silicate and carbonate rocks dissolution,and dissolution of salt in sediments),carbonate sedimentation,sewage,agricultural fertilizer and manure,and nitrification are the main driving factors of the variation of hydrochemical components of Baiyangdian Lake across three hydrological seasons.These findings suggest the need for effective control of substandard domestic sewage discharge,optimization of agricultural fertilization strategies,and proper management of animal manure to comprehensively improve the water environment in Baiyangdian Lake.

Characterization of rock thermophysical properties and factors affecting thermal conductivity−A case study of Datong Basin,China

Rock thermal physical properties play a crucial role in understanding deep thermal conditions,modeling the thermal structure of the lithosphere,and discovering the evolutionary history of sedimentary basins.Recent advancements in geothermal exploration,particularly the identification of high-temperature geothermal resources in Datong Basin,Shanxi,China,have opened new possibilities.This study aims to characterize the thermal properties of rocks and explore factors influencing thermal conductivity in basins hosting high-temperature geothermal resources.A total of 70 groups of rock samples were collected from outcrops in and around Datong Basin,Shanxi Province.Thermal property tests were carried out to analyze the rock properties,and the influencing factors of thermal conductivity were studied through experiments at different temperature and water-filled states.The results indicate that the thermal conductivity of rocks in Datong,Shanxi Province,typically ranges from 0.690 W/(m·K)to 6.460 W/(m·K),the thermal diffusion coefficient ranges from 0.441 mm^(2)/s to 2.023 mm^(2)/s,and the specific heat capacity of the rocks ranges from 0.569 KJ/(kg·℃)to 1.117 KJ/(kg·°C).Experimental results reveal the impact of temperature and water saturation on the thermal conductivity of the rock.The thermal conductivity decreases with increasing temperature and rises with high water saturation.A temperature correction formula for the thermal conductivity of different lithologies in the area is proposed through linear fitting.The findings from this study provide essential parameters for the assessment and prediction,development,and utilization of geothermal resources in the region and other basins with typical high-temperature geothermal resource.

Identified the hydrochemical and the sulfur cycle process in subsidence area of Pingyu mining area using multi-isotopes combined with hydrochemistry methods

Groundwater serves as an important water source for residents in and around mining areas.To achieve scientific planning and efficient utilization of water resources in mining areas,it is essential to figure out the chemical formation process and the ground water sulfur cycle that transpire after the coal mining activities.Based on studies of hydrochemistry and D,^(18)O-H_(2)O,^(34)S-SO_(4)isotopes,this study applied principal component analysis,ion ratio and other methods in its attempts to reveal the hydrogeochemical action and sulfur cycle in the subsidence area of Pingyu mining area.The study discovered that,in the studied area,precipitation provides the major supply of groundwater and the main water chemistry effects are dominated by oxidation dissolution of sulfide minerals as well as the dissolution of carbonate and silicate rocks.The sulfate in groundwater primarily originates from oxidation and dissolution of sulfide minerals in coal-bearing strata and human activities.The mixed sulfate formed by the oxidation of sulfide minerals and by human activities continuously recharges the groundwater,promoting the dissolution of carbonate rock and silicate rock in the process.

Progress and prospect of mid-deep geothermal reinjection technology

Mid-deep geothermal reinjection technology is crucial for the sustainable development of geothermal resources,which has garnered significant attention and rapid growth in recent years.Currently,various geothermal reinjection technologies lag behind,lacking effective integration to address issues like low reinjection rates and thermal breakthrough.This paper reviews the basic principles and development history of mid-deep geothermal reinjection technology,focusing on various technical methods used in the process and analyzing their applicability,advantages,and disadvantages under different geological conditions.It highlights the unique challenges posed by deep geothermal resources,including high temperature,high pressure,high stress,chemical corrosion,and complex geological structures.Additionally,it addresses challenges in equipment selection and durability,system stability and operation safety,environmental impact,and sustainable development.Finally,the paper explores future directions for mid-deep geothermal reinjection technology,highlighting key areas for further research and potential pathways for technological innovation.This comprehensive analysis aims to accelerate the advancement of geothermal reinjection technology,offering essential guidance for the efficient reinjection and sustainable development of geothermal resources.

Characteristics and genesis of groundwater salinization in coastal areas of the Lower Reaches of Oujiang Basin

The coastal areas of the lower reaches of Oujiang River Basin are rich in groundwater resources.However,the unsustainable exploitation and utilization of groundwater have led to significant changes in the groundwater environment.Understanding the characteristics and genesis of groundwater salinization is crucial for preventing its deterioration and ensuring sustainable utilization.In this study,a comprehensive approach combining the ion ratio method,mineral saturation index method and multivariate statistical analysis was employed to investigate the hydrochemical characteristics and main controlling factors in the study area.The findings reveal that:(1)Groundwater samples in study area exhibit a neutral to slightly alkaline pH.The predominant chemical types of unconfined water are HCO_(3)-Ca·Na,HCO_(3)·Cl-Na·Ca and HCO_(3)·SO_(4)-Ca·Na,while confined water mainly exhibits Cl·HCO_(3)-Na and Cl-Na types.(2)Salinity coefficients indicate an increase in salinity from unconfined to confined water.TDS,Na^(+)and Cl^(–)concentrations show an increasing trend from mountainous to coastal areas in unconfined water,while confined water displays variability in TDS,Na^(+)and Cl^(–)concentrations.(3)Groundwater salinity is mainly influenced by water-rock interactions,including the dissolution of halite and gypsum,cation exchange,and seawater intrusion etc.Additionally,human activities and carbonate dissolution contribute to salinity in unconfined water.Seawater intrusion is identified as the primary factor leading to higher salinity in confined water compared to unconfined water,with increasing cation exchange and seawater interaction observed from unconfined to confined water.

Revision of Handbook of Hydrogeology(2nd Edition)

Handbook of Hydrogeology is a professional reference book guiding the work and research of hydrogeology and providing enlightenment to hydrogeologists and those working in related fields.This paper introduces the revision and enlargement of Handbook of Hydrogeology(2ndedition) on the basis of its first edition.It gives a brief account of the background,principles,and necessity of revising the handbook.The content,features and application of the handbook are also addressed.

Assessment of Geological Security and Integrated Assessment Geo-environmental Suitability in Worst-hit Areas in Wenchuan Quake

The Wenchuan earthquake in 2008 and geo-hazards triggered by the earthquake caused large injuries and deaths as well as destructive damage for infrastructures like construction, traffic and electricity. It is urgent to select relatively secure areas for townships and cities constructed in high mountainous regions with high magnitude earthquakes. This paper presents the basic thoughts, evaluation indices and evaluation methods of geological security evaluation, water and land resources security demonstration and integrated assessments of geo-environmental suitability for reconstruction in alp and ravine with high magnitude earthquakes, which are applied in the worst-hit areas （12 counties）. The integrated assessment shows that： （1） located in the Longmenshan fault zone, the evaluated area is of poor regional crust stability, in which the unstable and second unstable areas account for 79% of the total; （2） the geo-hazards susceptibility is high in the evaluation area. The spots of geo-hazards triggered by earthquake are mainly distributed along the active fault zone with higher distribution in the moderate and high mountains area, in which the areas of high and moderate susceptibility zoning accounts for 40.1% of the total; （3） geological security is poor in the evaluated area, in which the area of the unsuitable construction occupies 73.1%, whereas in the suitable construction area, the areas of geological security, second security and insecurity zoning account for 8.3 %, 9.3% and 9.3 % of the evaluated area respectively; （4） geo-environmentai suitability is poor in the evaluated area, in which the areas of suitability and basic suitability zoning account for 3.5% and 7.3% of the whole evaluation area.

Numerical simulation and environmental impact prediction of karst groundwater in Sangu Spring Basin,China

The changes of development and utilization of karst groundwater in Sangu Spring Basin have made the original groundwater resource evaluation unable to meet the needs of future economic development.Based on analysis of existing data,combined with the characteristics of supplement,runoff and draining of regional karst groundwater,the Visual Modelflow software was used to build a numerical simulation model of Sangu spring Basin.The amount of karst groundwater resource and groundwater environment of the Basin were evaluated under different exploitation schemes,and the changes of karst groundwater environment in the future ten years were also predicted.The fitting error which is less than 0.5 m between the calculated value and measured value of the water level in the fitted borehole accounts for 93%.For the lithologically and structurally complex Sangu Spring Basin,the fitting effect of numerical simulation model was ideal.On the basis of the current mining amount of 111.80 million m3/a,the total redistributed exploited amount in the spring region was 61.79 million m3/a.Under the condition that the quantity of recoverable resources reached 173.59 million m3/a and under different precipitation schemes,all constraint conditions were satisfied,such as regional water level drawdown,maximum allowable water level drawdown in every simulated water source area and the flow rate of Guobi Spring.The results will provide a scientific basis for the rational development and utilization of karst groundwater in Sangu Spring Basin.

Research hotspots and trends of groundwater and ecology studies:Based on a bibliometric approach

Groundwater,as a critical component of the hydrological cycle,is essential for sustainable ecosystem development.To clarify the current status of domestic and overseas research,and to identify hotspots,frontier and future trends of groundwater and ecology research,this study utilizes bibliometric methods and CiteSpace software to examine relevant published articles in the Web of Science(WOS)and CNKI databases from 1978 to 2022.Specifically,this study analyzes(1)the annual number of published papers;(2)research institutions;(3)keywords;and(4)evolution of research hotspots.The findings reveal that the United States,China,and Germany are the top three countries in groundwater and ecology research.International research hotspots mainly focus on microbial ecology,climate change,groundwater-surface water interactions in the hyporheic zone,biodiversity,and submarine groundwater discharge,while domestic research hotspots mainly focus on ecological water conveyance,ecological flow,groundwater development and utilization,groundwater pollution,and groundwater and ecological protection.Both domestic and international research hotspots exhibit interdisciplinary features with diverse research objects and assessment methods.Future research in this area is expected to focus on topics such as contamination,groundwater quality,framework,mechanism,spatial distribution,and dissolved organic matter.Additionally,the study of ecological recharge,ecological flow,ecological protection,water intake and use will continue to be the hot topics domestically.

Health risk assessment of heavy metals in soils and crops in a mining area(Au-Ag-Cutrona-oil et al.) of the Nanyang Basin, Henan Province, China

Heavy metal distribution in mining areas has always been a hot research topic due to the special environment of these areas. This study aims to explore the impact of heavy metal pollution on soils and crops in the study area, ensure the safety of local crops and the health of local residents, and provide a basis for the subsequent environmental restoration and the prevention and control of environmental pollution. Based on the analysis of the heavy metal concentrations in local soils and crops, the study investigated the spatial distribution, pollution degrees, and potential ecological risks of heavy metals in the farmland of a mining area in the southeastern Nanyang Basin, Henan province, China explored the sources of heavy metals and assessed the health risks caused by crop intake. The results of this study are as follows. The root soils of crops in the study area suffered heavy metal pollution to varying degrees. The degree of heavy metal pollution in maize fields is higher than that in wheat fields, and both types of fields suffer the most severe Cd pollution. Moreover, the root soils of different crops suffer compound pollution.The root soils in the maize fields suffer severe compound pollution at some sampling positions, whose distribution is similar to that of the mining area. Cd poses the highest potential ecological risks among all heavy metals, and the study area mainly suffers low and moderate comprehensive potential ecological risks. The principal component analysis(PCA) shows that the distribution of Zn, Cd, Pb, and As in soils of the study area is mainly affected by anthropogenic factors such as local mining activities;the distribution of Cr and Ni is primarily controlled by the local geological background;the distribution of Hg is mainly affected by local vehicle exhaust emissions, and the distribution of Cu is influenced by both human activities and the geological background. Different cereal crops in the study area are polluted with heavy metals dominated by Cd and Ni to varying degrees, especially wheat. As indicated by the health risk assessment results, the intake of maize in the study area does not pose significant human health risks;however, Cu has high risks to human health, and the compound heavy metal pollution caused by the intake of wheat in the study area poses risks to the health of both adults and children. Overall, the soils and crops in the study area suffer a high degree of heavy metal pollution, for which mining activities may be the main reason.

Current status and prospects of research on 1,4-dioxane pollution and treatment technologies in the water environment

1,4-dioxane pollution is characterized by its early identification, widespread sources and extensive distribution. The pollutant is highly mobile and persistent in the water environment and is classified as a B2(probable) human carcinogen. After reviewing recent researches on the pollution status,transport and transformation characteristics of 1,4-dioxane in the water environment, as well as the environmental pollution remediation and treatment technologies, and the status of environmental regulation,this paper addresses that the distribution of 1,4-dioxane in water bodies is significantly correlated with chlorinated hydrocarbon pollutants such as 1,1,1-trichloroethane(1,1,1-TCA) and trichloroethylene(TCE).It is noteworthy that 1,4-dioxane often occurs in symbiosis with 1,1,1-TCA and has a similarity contamination plume distribution to 1,1,1-TCA. The natural attenuation of 1,4-dioxane in groundwater environment is weak, but there is a certain degree of biological oxidation attenuation. Current methods for treating 1,4-dioxane pollution mainly include extraction-treatment technology, advanced oxidation treatment technology, modified biological treatment technology and phytoremediation technology, all of which have their limitations in practical application. Currently, there is no environmental regulation available for the 1,4-dioxane pollution worldwide, and no enforceable standard established for defining the health trigger levels of 1,4-dioxane in drinking water. Research on this contaminant in China is generally limited to the site or laboratory scale, and there are no studies on the environmental risk and quality standards for 1,4-dioxane in the water environment.