Plain River Network Research Articles

The impacts of water diversion on hydrodynamic regulation of plain river network

平原河网多存在河道流动性不强，河道生态流速难以保障的问题，以典型平原河网地区——宁波市海曙区为例，开展野外原型同步监测，以河道分流比、换水率及槽蓄量为研究对象，系统分析引调水工程对河网水动力的调控效果.结果表明：平原河网水动力改善效果与引排水口分布、引水流量密切相关，为保证河网区水体交换良好，引排水口的连线应尽可能贯通整个区域；平原河网换水率在空间分布上具有很强的异质性（4种调水方案下河道换水率极差，最大为190%，最小为75%），引调水工程能够改善分流能力大的支汊的水动力特征，对分流能力小的支汊及断头河的水动力状况帮助不大；河网换水率提高、槽蓄量变化率减小是区域水动力改善的必要条件，海曙区较小的槽蓄量变化率为0.2%左右.本研究分析了河网区的河道输水能力以及换水率，对优化河网概化密度以减小模拟偏差有参考意义，为进一步探究平原河网水动力改善促进水环境质量提升提供基础，利于特殊水动力特征河道治理和区域水环境管控.;In the plain river network area, the mobility of rivers is usually poor and the ecological flow velocity of rivers is difficult to be guaranteed. Taking Haishu District of Ningbo City, a typical plain river network area, as an example, a field prototype synchronous monitoring experiment was carried out. The effect of water diversion on hydrodynamic regulation was systematically studied with the river diversion ratio, water exchange rate and storage capacity as the research objects. The results showed that:The hydrodynamic improvement effect of plain river network was closely related to the position of water inlets and outlets and water diversion flow. To ensure a good water exchange rate, the connection of water inlets and outlets should run through the whole area as far as possible. The water exchange rate of plain river network area had strong heterogeneity in spatial distribution (under the four schemes, the maximum range of water exchange rate was 190% and the minimum was 75%). The water diversion project could improve the hydrodynamic characteristics of the branches with large diversion capacity, but it was not helpful for the branches with small diversion capacity and truncated creek. The improvement of regional hydrodynamic needed to increase the water exchange rate and decrease the change rate of storage capacity, the smaller change rate of storage capacity in Haishu district was about 0.2%. The study analyzed the water conveyance capacity and water exchange rate, which has reference value for optimizing the generalized density of river network to reduce the simulation deviation and provides a basis for exploring the improvement of water dynamics in plain river network and promoting the water environment quality. It will also be conducive to river regulation with special hydrodynamic characteristics and regional water environment control.

Sieved Transport and Partitioning of Metals in Plain River Networks with Sedimentary Resuspension and Implications for Downstream Lakes

Sieved Transport and Partitioning of Metals in Plain River Networks with Sedimentary Resuspension and Implications for Downstream Lakes

Evaluation of the effect of water diversion on improving water environment in plain river network under the multi-objective optimization

引调水是改善平原河网地区水环境的重要方法之一，通过构建太湖流域走马塘东南片平原河网区一维水动力水质数学模型，研究不同引调水方案对区域水环境改善效果，确定引调水过程中的异质性因子.从决策目标、水质指标、空间指标3个层面综合考虑，构建环境效益与经济效益结合的多目标函数及评价体系，对引调水方案进行评估优选.结果表明：引调水流量较大时，能够在一定程度上改善区域水环境状况，规划方案下引调水5 d后，高锰酸盐指数、氨氮、总磷的平均改善率分别为30.7%、22.2%、26.4%；引调水时，区域河网中不同空间点位、不同水质指标之间的水质改善过程与效果都存在一定异质性；引调水水量、调度模式及污染源分布都会对调水后的河网区水质产生差异性影响；本研究建立的多目标评价体系较现有方法能够有效涵盖引调水中存在的异质性因子，从多个目标层面优选引调水方案，实现水量水质综合优化调控，为平原河网地区水环境长效管理与科学决策提供理论参考.;Water diversion is a significant method to improve the water environment in the plain river network area. Through building up the one-dimensional hydrodynamic and water quality model of the plain river network area of southeast Zoumatang of Taihu Basin, the effect on water environment of different water diversion schemes was simulated, and the heterogeneous factors in the process were determined. A multi-objective function and evaluation system combining environmental benefits and economic benefits were constructed from three aspects, including decision-making, water quality indexes and spatial indexes, and the water diversion schemes were evaluated and optimized. The results show that: (1) With a larger flow, water diversion can improve the regional water environment to some extent. After 5 days of water diversion under the planning schemes, the average improvement rates of COD_Mn, ammonia nitrogen and total phosphorus were 30.7%, 22.2% and 26.4%, respectively. (2) Heterogeneity existed in the process and effect of water quality improvement in different spatial points and water quality indexes in the river network during water diversion. (3) The water quantity and dispatching mode of water diversion as well as distribution of pollutants all have different effects on the water quality in the river network. (4) Compared with the existing method, the multi-objective evaluation system of water diversion established in this research can effectively cover the heterogenous factors and evaluate and optimize different water diversion schemes from multiple objectives, therefore can achieve comprehensive optimization and control of water quantity and quality, and provide theoretical reference for long-term management and scientific decision-making of water environment in the plain river network area.

Effects of ecological water diversion in coastal plain river network considering different control plans

The water environment in coastal plain river network becomes serious due to its dense population and low flow rate, the ecological water diversion is widely accepted as an effective method to improve the water quality in coastal areas. As a typical coastal city in China, Pinghu city has suffered from the serious water quality problem for years especially in the downtown area. Therefore, the local water diversion project has been constructed since 2010 for the purpose of providing an efficient way to improve the river network water quality. However, a systematic research of the control plan of water diversion is still necessary. In this study, a numerical model is introduced to predict the improvement of river network water quality considering different control plans. The simulation results comparison among different water diversion control plans show than the pre-drainage plan obtains the best water quality in this coastal plain river network, and it becomes a good choice for the local government to further improve the regional water environment.

Water quality assessment of the river network in Wenzhou city using PCA-BP neural network model

The water quality assessment is often challenged by how to determine the index weight and simplify the evaluation model. This paper proposed an integrated model called PCA-BP neural network model to solve the problem, which combines the dimensionality reduction capability of the improved principal component analysis (PCA) method with the self-learning ability of back propagation (BP) artificial neural networks. And its application for the plain river network in the main districts of Wenzhou city indicated that the evaluation result of PCA-BP was consistent with the single-factor method and PCA method in overall trend. It was demonstrated that PCA-BP model could evaluate the water quality of the study area more reasonably and accurately, as it avoided the disadvantage of a certain factor completely covering the information of the other ones in the single-factor method and the risk of over-optimism in PCA method as well.

Effect of Heavy Rainfall on Nitrogen and Phosphorus Concentrations in Rivers at River-net Plain

To understand the quantitative effect of heavy rain on nitrogen and phosphorus pollution in river-net plain, daily observations of nutrient concentrations in two rivers, flowing into Lake Taihu, were conducted from 1st September, 2017 to 31st August, 2019. The daily rainfall was recorded by auto-recording meteorological stations located on the two rivers and the Taihu Laboratory for Lake Ecosystem Research. Intensive sampling in different sections of the two rivers during Super Typhoon Lekima was also conducted in August 2019. Using these datasets, the influence of heavy rainfall on various forms of nitrogen and phosphorus concentrations in the rivers, and its environmental effects, were analyzed. The results showed that 16 heavy rainfall events (19 d) were observed in two years, 50% of which occurred in the summer season. In addition, heavy rainfall accounted for as much as 41.33% of the total rainfall over the entire year. After the period of heavy rainfall, the concentrations of various forms of nitrogen and phosphorus increased, and the particulate P generally exhibited the fastest response, usually peaking on the day of heavy rainfall. In contrast, the peaks of N were delayed for 2-5 days with the occurrence of heavy rain. In general, the duration of the increase in the concentration of nutrients in the study river caused by heavy rainfall was short (usually 1-2 days), and sometimes was lower than the concentration before the rains. The Dapu River exhibited a slower response to heavy rains than the Yincun River because it has a larger and longer catchment area than the Dapu River. In addition, the effect of heavy rain on N and P concentrations was also strongly influenced by the land-use situation around the river basin. The increase of nitrogen in the reach, affected by agricultural non-point sources, was dominated by granular nitrogen, and the increase of nitrogen in the reach affected by urban non-point sources was dominated by dissolved nitrogen. The increase of phosphorus was dominated by granular phosphorus in the entire process. The conclusions of this study are as follows:In the plain river network area, the fluctuations of nitrogen and phosphorus concentrations in the river water body caused by heavy rainfall are small, and the response of various forms of nitrogen and phosphorus are significantly affected by the local environmental background. Therefore, the water quality generally exhibited limited variation. Due to the large proportion of water entering the lake during heavy rainfall events, a high level of the nutrient loading was also observed, and the occurrence of heavy rainfall was occasional. The short-term effect of heavy rainfall on the nitrogen and phosphorus loading entering the lake in the river channel in the plain river network area is therefore, also significant, and requires further investigation.

Simulation of Wastewater Discharge in a Coastal Plain River Network Considering Different Boundary Conditions

Fu, L.; Wang, J.M., and Peng, Z.H., 2020. Simulation of wastewater discharge in a coastal plain river network considering different boundary conditions. In: Guido Aldana, P.A. and Kantamaneni, K. (eds.), Advances in Water Resources, Coastal Management, and Marine Science Technology. Journal of Coastal Research, Special Issue No. 104, pp. 529–534. Coconut Creek (Florida), ISSN 0749-0208.Owing to a rapidly developing economy and society, coastal cities along the East China Sea face serious water pollution problems. A number of sewer plants were recently constructed to improve the water quality in the region. This study investigated the environmental effects of wastewater discharge from a newly constructed sewer plant as the wastewater passes through a typical coastal plain river network. Ammonia nitrogen (NH3-N) was selected as the typical pollutant, which was monitored and simulated using a two-dimensional model to demonstrate the effects of wastewater discharge. Different kinds of boundary conditions and the effects of tidal bores were represented in the simulation, and the risk of wastewater discharge in the coastal plain river network was also analyzed. An emergency plan is recommended to minimize the risk of wastewater discharge and prevent potential damage to the regional river network environment.

Transport and fate of microplastics from riverine sediment dredge piles: Implications for disposal

Microplastics (MPs) are an environmental problem of growing concern. Aquatic sediments are considered as a final sink for MPs, but dredging can remobilize sedimentary MPs into both aquatic and terrestrial ecosystems. Although dredging is globally used for waterway deepening and ecological restoration, the environmental impacts of dredging on MP pollutants has not been previously assessed. In this study, Nile Red staining combined with micro-FTIR methods showed sediments containing high MP concentrations (6060–37610 n/kg·DW) from urban/suburban segments of a plain river network in Southeast China. The dredged sediments were stored in piles on farmlands, whereby MPs were subsequently dispersed to surrounding soils and surface waters while awaiting a permanent disposal option. MP concentrations in the soils surrounding the pile were higher in the dry season (wind dispersion), while MP concentrations in waters downstream of the piles were higher in the wet season (rainfall/runoff erosion). Whether dredge sediments are finally used to fertilize farmland, as fill material for coastal land reclamation or dumped into the ocean, MPs have the potential for remobilization into the environment causing concerns with aquatic food webs, agricultural production and human health. Therefore, disposal of dredge sediments containing MPs requires careful assessment to minimize potential environmental impacts.

Multiphase distribution and spatial patterns of perfluoroalkyl acids (PFAAs) associated with catchment characteristics in a plain river network

Perfluoroalkyl acids (PFAAs) have emerged as global concerning contaminants because of their persistence, bioaccumulation, and toxicological effects. The transport and fate of PFAAs on dimension of plain river networks (PRNs) are difficult to model due to the unique regional characteristics (i.e., undirectional flows, low slope, complicated structure and connectivity) and the lack of data on PFAAs concentrations and compositions. A typical PRN (Taihu Basin, China) was selected to elucidate the spatial patterns of PFAAs in multi-matrices, including colloidal phase, soluble phase, suspended particles, and sediment. PFAAs were ubiquitously detected in plain rivers with total concentrations of 18.48–1220 ng/L in colloids, 139.07–721.37 ng/L in soluble phase, 97.69–2247 ng/g dw in suspended particles, and <72.04–178.12 ng/g dw in sediment. PFAAs were more likely to transport via dissolved phase and accumulate into sediment. Colloids carried 45.46–62.59% of ∑PFAAs in overlying water, while suspended particles contained <36.63% of ∑PFAAs, suggesting the important role of colloids in preloading PFAAs. Moreover, PFAAs variability was correlated with indicators of the structure and connectivity of river network by gray relational analysis. The mean gray relational degrees can be sorted as edge-node ratio (0.7609) > network connectivity (0.7191) > river density (0.7012) > water surface ratio (0.6887) > river development coefficient (0.6504) > functional connectivity (0.4780). These results suggested that the effects of catchment characteristics should be taken into account in understanding PFAAs fate in the PRNs.

Characteristics and Causes of Long-Term Water Quality Variation in Lixiahe Abdominal Area, China

The Lixiahe abdominal area is a representative plain river network in the lower reaches of the Huai River, being an upstream section of south-to-north water diversion from the Yangtze River in Jiangsu Province, China. The assessment of long-term water quality variation and the identification of probable causes can provide references for sustainable water resources management. Based on the monthly water quality data of 15 monitoring stations in the Lixiahe abdominal area, the periodic characteristics and tendency of water quality variation were studied by combining wavelet analysis, the Mann–Kendall trend test, and Sen’s slope estimator, and the correlation between water quality variation, water level, and water diversion was discussed with cross wavelet transform and wavelet coherence. The results show that the comprehensive water quality index (CWQI) included periodic fluctuations on multiple scales from 0.25 to 5 years. The CWQI of 7 out of 15 monitoring stations has a significant decreasing trend, indicating regional water quality improvement. The trend slope ranges from −0.071/yr to 0.007/yr, where −0.071/yr indicates the water quality improvement by one grade in 15 years. The spatial variation of water quality in the Lixiahe abdominal area was significant. The water quality of the main water diversion channels and its nearby rivers was significantly improved, while the improvement of other areas was not significant or even became worse due to the increasing discharge of pollutants. The CWQI of the main water diversion channels and its nearby rivers was inversely correlated with the amount of water diversion. The greater the amount of water diversion, the better the water quality. The water diversion from the Yangtze River has played an important role in improving the regional water environment.

Impact of intensive land use on heavy metal concentrations and ecological risks in an urbanized river network of Shanghai

• Concentrations and spatial distribution of HMs in the river network were influenced by intensive land use. • AVS and TOC in river sediments influenced the migration and transformation of Cd, Hg and Zn. • Hg and Cd were the main contributors of RI, HMs in the central city area showed the highest potential ecological risk. • HMs in the river network primarily originated from industrial activities, traffic emissions and coal-burning emissions. Heavy metal pollution characteristics in the urbanized river network are closely related to urban land use. The existing studies mainly focused on the pollution characteristics of heavy metals in single rivers, but fewer studies reported the impact of land use on the concentrations and ecological risks of heavy metals in surface water and sediments of the urban river network. This study combined land use types with heavy metal pollution in rivers, and explored the specific impact of intensive land use on the characteristics of heavy metal pollution in rivers, which provided scientific basis for the study of heavy metal pollution in plain river networks. The concentrations, spatial variations and potential ecological risk levels of cadmium (Cd), chromium (Cr), copper (Cu), mercury (Hg), lead (Pb) and zinc (Zn) in surface water and sediments from five different intensive land use areas of Shanghai river network (industrial areas, agricultural areas, central city, suburban towns and Chongming Island) were analyzed. Results showed the concentrations of Cd, Cr, Cu, Pb and Zn in surface water of the Shanghai river network were relatively low, but Hg pollution existed in some rivers. Influenced by intensive land use, heavy metal concentrations in the central city were generally higher than those in other areas. Heavy metals in sediments had considerable ecological risk, in which Hg and Cd were the main contributors, and showed the highest potential ecological risk in central city. Acid volatile sulfides (AVS) and total organic carbon (TOC) in river sediments affected the migration and transformation of Cd, Hg and Zn. Industrial activities, traffic emissions and coal-burning emissions were the main sources of heavy metals. Intensive land use caused by anthropogenic activities led to the weakening of hydrodynamic conditions and the discharge of a large number of pollutants into the river network. In the central city with intensive anthropogenic activities, heavy metals in the river network showed higher levels than those in other areas. This study found that intensive land use and high-intensity anthropogenic activities led to the high pollution level of heavy metals in the plain urbanized river networks. Quantitative analyses of the effects of intensive land use on heavy metal pollution in urbanized river networks were suggested to conduct further to protect the urban river water quality.

Performance assessment of coupled green-grey-blue systems for Sponge City construction

In recent years, Sponge City has gained significant interests as a way of urban water management. The kernel of Sponge City is to develop a coupled green-grey-blue system which consists of green infrastructure at the source, grey infrastructure (i.e. drainage system) at the midway and receiving water bodies as the blue part at the terminal. However, the current approaches for assessing the performance of Sponge City construction are confined to green-grey systems and do not adequately reflect the effectiveness in runoff reduction and the impacts on receiving water bodies. This paper proposes an integrated assessment framework of coupled green-grey-blue systems on compliance of water quantity and quality control targets in Sponge City construction. Rainfall runoff and river system models are coupled to provide quantitative simulation evaluations of a number of indicators of land-based and river quality. A multi-criteria decision-making method, i.e., Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) is adopted to rank design alternatives and identify the optimal alternative for Sponge City construction. The effectiveness of this framework is demonstrated in a typical plain river network area of Suzhou, China. The results demonstrate that the performance of Sponge City strategies increases with large scale deployment under smaller rainfall events. In addition, though surface runoff has a dilution effect on the river water quality, the control of surface pollutants can play a significant role in the river water quality improvement. This framework can be applied to Sponge City projects to achieve the enhancement of urban water management.

Impact of urbanization on stream structure and connectivity of plain river network in the Taihu Basin

Impact of urbanization on stream structure and connectivity of plain river network in the Taihu Basin

Performance of water transfer in response to water environment issues in Wuxi, China

The continuous development of industrialization and urbanization resulted in increased pollution in plain river network areas. In response to water environment issues, water transfer can be a countermeasure to improve water environment. There are five basic elements to be determined of water transfer, i.e., water sources, water transfer patterns, regulating rules, water transfer routes, and flow rate of water transfer. In Wuxi City, needs for water transfer were analyzed from the five aspects above. The former three elements were determined based on the results of water transfer measurements. The water source was Yangtze River, the pattern was continuous water transfer, and regulating rules were water transferred by pumping stations and drained by sluices and pumping stations. Besides, a water quantity and quality coupling model was constructed to analyze routes and flow rate of water transfer. Different flow rate of water transfer, from 80 to 130m3/s, were analyzed. According to the characteristics of regional river system and the requirements of flood control, the Baiqugang River was taken as the clean water route, and the urban flood control enclosure was taken as the clean water transfer station. In the end, it was concluded that the optimal flow rate is 110m3/s based on the results of different schemes. It indicates that a proper scheme of water transfer can better improve the water environment in plain river network areas.

Stream order and connectivity affect phosphorus distribution in plain river network

ABSTRACT The order and connectivity of streams influence phosphorus distribution extensively. In this work, the space-and-time variabilities of total phosphorus (TP), particulate phosphorus (PP), total dissolved phosphorus (TDP), dissolved reactive phosphorus (DRP), and dissolved unreactive phosphorus (DUP) in streams of three orders (Ⅰ, Ⅱ, ⅡⅠ) were analyzed during each spring of 2016-2018 in a plain river network area, China. The results show that: ① PP was the main form of TP and DRP was the main form of TDP. ② The average concentrations of phosphorus in the order Ⅰ streams were significant larger than those in the order ⅡⅠ The concentrations of TP, PP, TDP, and DRP in the poor-connected streams were considerably higher than those in the well-connected streams. Therefore, it is essential to implement effective practices to improve the protection and appropriate connectivity of small streams in plain river network areas.

Total pollutant load allocation in plain river network based on the entropy-environmental gini coefficient method

Total pollutant load allocation in plain river network based on the entropy-environmental gini coefficient method

Influence of Rainfall Intensity on the Nutrient Loading from an Inflowing River in the Plain River Network of the Taihu Catchment

To reveal the law of external pollution in the plain river network of the Taihu catchment, we investigated nitrogen, phosphorus, and dissolved organic carbon daily, as well as automatic recording data for flow rate and rainfall in Dapu River from 1st March, 2017 to 28th February, 2018. Dapu River, a typical inflowing river of Lake Taihu, usually has a reciprocating flow. A reciprocating flow is a common condition in the plain river network located in the Yangtze Delta. The response flow rate in the river was relatively slow to different intensities of rainfall. Flow rate significantly increased only when the rainfall intensity reached heavy rain (>25 mm·d-1). The concentrations were statistically non-significant under different rainfall intensities, and the concentrations of total nitrogen averaged 3.00±0.58, 3.34±0.93, 3.55±1.05, and 3.37±1.14 mg·L-1 under heavy rain (>25 mm·d-1), medium rain (10 mm·d-1-25 mm·d-1), light rain (<10 mm·d-1), and no rain. The concentrations of total phosphorus averaged 0.228±0.068, 0.258±0.121, 0.219±0.083, and 0.225±0.121 mg·L-1, respectively. The concentration of dissolved organic carbon and nitrogen in the Dapu River changed little during the 3 typical rainfall processes, but the concentration of phosphorus increased significantly after heavy rain when the duration was 2 days. The concentration of total phosphorus and particulate phosphorus increased significantly after medium rain when the duration was 1 day. The concentration of phosphorus did not show an obvious change after light rain. The concentration of total nitrogen was the highest under light rain, and the concentration of total phosphorus was the highest under medium rain. The daily loadings of total nitrogen from the Dapu River to Lake Taihu were 7.64, 3.19, 3.21, and 2.62 t·d-1 under conditions of heavy rain, medium rain, light rain, and no rain, respectively. The daily loadings of total phosphorus were 0.59, 0.26, 0.22, and 0.20 t·d-1 under conditions of heavy rain, medium rain, light rain, and no rain, respectively. Although the daily loading of nutrients under heavy rain conditions was the highest, the contribution of annual nutrient loading was small during heavy rain days. The reason was that the percentage of heavy rain during the entire year was small. The total nitrogen loading in heavy rain days was 61.11 tons in the observatory year, which was only 5.6% of annual loading. The total phosphorus loading in heavy rain days was 4.72 tons, which was only 5.8% of the annual loading. These low percentages of nutrient loading under heavy rainfall are quite different from situations in mountain catchments. This research showed that the transport processes of nutrients in the plain river network was complicated and its influence on nutrient concentrations and loadings in connected rivers was slow and indirect. The amount of inflow water was an important source of external nutrient loading in the plain river network. These conclusions have reference value for estimating the external loading and deciding non-point control policy of lakes in plain river network of the Taihu catchment.

Research on the Water Diversion Ratio Characteristics of the Plain River Network--A Case Study of the Channel in Zhangjiagang

This study combined numerical simulation with field observation, and this study took the classical bifurcated river of Zhangjiagang as an example and built a two- dimensional hydrodynamic model of the river course upon it. In addition, this project studied the influencing factors and the mechanism of the flow diversion ratio in the plain river network and established a formula to estimate the flow diversion ratios in plain river networks with ridge regression. The results show that: (1) the water diversion ratio in plain rivers has a positive correlation with the roughness, the ratio of the width of the tributary to that of the main channel and the water level differences. The water diversion ratio has a negative correlation with the mainstream discharge. (2)The mainstream discharge and the ratio of the width of a tributary to that of the main channel are two dominant factors ofthe flow diversion ratio.(3)By establishing an equation for the water diversion ratio, the water diversion ratio in the plain river network can be predicted.

Water Environmental Capacity Calculation and Allocation of the Taihu Lake Basin in Jiangsu Province Based on Control Unit.

The water quality target management of the control unit is a convenient and direct technology for water environment management and the development direction of water environment management in China, involving control unit division and water environment capacity calculation. Taking the Taihu Lake Basin in Jiangsu Province as an example, we propose herein the basic principle of the division of a regional control unit in a plain river network and the method of analyzing the rationality of the control unit division. On this basis, the Taihu Lake Basin in Jiangsu Province was divided into 70 control units. To calculate the water environmental capacity in the plain river network area, we established a water environmental capacity calculation framework based on multiple targets of lakes and rivers, and proposed the goal of water quality “double compliance” of the water environmental functional zone and the assessment section. For this study, we calculated the regional water environmental capacity using the mathematical model of the Taihu Lake Basin’s water environmental capacity, and the water environmental capacities of the 70 control units were allocated by the weight coefficient method, which established water area and functional division length. The research results described herein were applied to the pollution permit management of the Taihu Lake Basin in Jiangsu Province. It provides important technical support for the establishment of a pollution permit system based on the total capacity to improve environmental quality.

Occurrence and health risk assessment of polycyclic aromatic hydrocarbons (PAHs) in water resources of the typical plain river network area

Drinking water sources play a significant role in providing water for urban residents and public services. The pollution and health risk of polycyclic aromatic hydrocarbons in drinking water sources have attracted extensive attention. In this study, river water samples were collected from two drinking water resources of the typical plain river network area in eastern China, and tap water samples were collected from public places. The concentration of the 16 priority PAHs in river water and drinking water were determined by SPE-GC-MS. The results indicated that the concentrations of Σ16PAHs ranged 128-183 ng/L in the autumn and 61.3-87.3 ng/L in the winter, respectively. The cancer risks and non-cancer risks of adults associated with drinking water intake were low, but it still deserved more attention.