Organochlorine compounds and polycyclic aromatic hydrocarbons in surface sediment from Baiyangdian Lake,North China:Concentrations,sources profiles and potential risk

Organochlorine pesticides （OCPs）, polychlorinated biphenyls （PCBs）, and polycyclic aromatic hydrocarbons （PAHs） were determined in nineteen surface sediment samples collected from Baiyangdian Lake and its inflowing river （Fuhe River） in North China. Total concentrations of OCPs, PCBs and PAHs in sediments ranged from 5.4 to 707.6 ng]g, 2.3 to 197.8 ng/g, and 101.3 to 6360.5 ng]g, respectively. The levels of contaminants in Fuhe River were significantly higher than those in Baiyandian Lake. For hexachlorocyclohexane （HCHs） and dichlorodiphenytrich/oroethanes （DDTs）, α-HCH and p,p＇-DDT were predominant isomers; while for PCBs, PCB 28/31, PCB 40/103, PCB 60, PCB 101, and PCB 118 were predominant congeners. Possible sources derived from historical usage for OCPs and incomplete combustion fuel, wood, and coal and exhaustion of boats or cars for PAHs. Risk assessment of sediment indicated that sediments in Fuhe River were likely to pose potential biological adverse impact.

Shrinking and Drying up of Baiyangdian Lake Wetland:A Natural or Human Cause?

The shrinking and drying up of wetlands in arid and semiarid areas of China have been widely observed in the recent years, but there has been no consensus on whether the aggravation is caused by human activities or by global climate warming. For a better understanding of the cause, this study investigates the dynamic changes of Baiyangdian Lake wetland over the last 40 years. It is shown that since the 1980s, Baiyangdian Lake has suffered from an insufficient water input and shrunk considerably. By using SPSS 11.0, this study urines a detailed Analysis on the signifficance of the effects of the possible driving factors for the degradation. It is identified that the North China Plain has been warrnin~ up significantly in recent years, which causes a significant reduction in the precipitation and inflow to the lake. Although human disturbances such as the irrigation and storage of water in reservoirs do not play a decisive role, they accelerate the degradation and their effects should be minimized.

Impact of transferred water on the hydrochemistry and water quality of surface water and groundwater in Baiyangdian Lake,North China

The hydrochemical composition of surface water and groundwater is a key parameter for understanding the evolution of water and its quality.In particular,little is known about the impact of transferred water on surface water and groundwater.In this study,Baiyangdian Lake was selected as a typical area for extensive groundwater exploration and surface water transfer in the North China Plain.Surface water and groundwater samples were sampled in dry/wet seasons and then analyzed before/after the water transfer,respectively.Generally,surface water and groundwater are extensively hydrologically connected based on hydrochemical evidence.It was found that the hydrochemical composition of the shallow groundwater is affected by the surface water and that the water quality of the deep groundwater is stable.However,inter-aquifer recharge processes from the shallow groundwater to the deep groundwater existed in the anthropogenic region impacted with high nitrate-ion concentrations.Also,the hydrochemical composition of the surface water and groundwater was dominated by rock-weathering and evaporation-precipitation processes.Due to the existence of the deep vadose zone in the alluvial fan,Na^(+)was exchanged into soil matrices during the leakage of the surface water.In addition,the transferred water resulted in surface water with good quality,and it also played as an important recharge source to groundwater.As the most important water resource for irrigation and drinking,deep groundwater should be paid more attention in the alluvial fan with frequent water transfer and extensive groundwater exploration.

Comprehensive Study on Degradation and Management of Baiyangdian Lake in North China

Baiyangdian lake as the kidney of north China plays a huge ecological function, bringing about environmental and economic benefits as well as aesthetics value. It takes the role of adjusting climate, slowing flood, storing water, alleviating drought, maintaining the water body＇s purifying capacity, protecting biodiversity as well as vegetating fish and reed, developing eco-tourism etc.. Now it is degenerating under the pressure from both physical and human society. This paper studied the process, condition and root causes of the lake shrinking, pollution, biodiversity losing and disasters. Adaptation and integrative management strategies are also put forward for maintaining the ecological function and sustainable development.

The Benchmark and Model of Literature in the New Era:On Above Baiyangdian Lake

Above Baiyangdian Lake is a novel set against the backdrop of the great changes in rural China in the new era,revolving around the grand theme of China's contribution to the harmonious development of the world with Chinese wisdom and its solutions.The subject of Above Baiyangdian Lake is grand as it involves politics,culture,economy,and many other aspects.Its publication has reversed the narrowing tendency of Chinese novels in terms of themes and subjects.Above Baiyangdian Lake reconstructs historical time for Chinese modernization with its time consciousness based on a historical perspective.Wang Juexin and Qiao Mai shaped by the writer have contributed to the range of Chinese contemporary literary characters as typical images of the new characters of the era.The value of epic masterpieces like Above Baiyangdian Lake should be fully explored and advocated to provide a useful reference for the development of literature in the newera.

History,Narrative and Realism:Above Baiyangdian Lake by Guan Renshan

Telling Chinese stories and Chinese experience is an important theme of realist literature in the new era.Chinese writers in the new era face the significant challenge of how to understand the"totality of China"and how to construct the totality spirit and aesthetic character of the"Chinese"narrative.Above Baiyangdian Lake by Guan Renshan takes the historical changes that occurred in the typical environment of Baiyangdian New Area as the content of narration,revealing the growth of people and history and its"Chinese"connotation through the story of the growth of"new character"in the new era.The novel depicts the"rediscovery"and rebirth of history and traditions of China in the new era by"telling stories,"and puts them under a profound context of the past and present and in a broad vision of China and foreign countries,thus constructing the overall aesthetics of realism in contemporary China with an epic grand narrative.The novel artistically shows the building and growth process of China in the new era,and demonstrates its leveraging of resourcesand unique connotation.It is a typical text for understanding the relationshipbetween theimage shaping of China in the new era and Chinese realism literature,as well as the connotation,function and form of Chinese realism.

Sense of the Scene,Reflexivity,and New Local Writing:On Above Baiyangdian Lake by Guan Renshan

Above Baiyangdian Lake is a meticulously crafted novel by Guan Renshan nearing a million words in length.The novel offers a panoramic view of everyday life in Baiyangdian Lake and the development of the Xiong'an New Area.The novel exemplifies a genuine sense of the scene by presenting readers with a vivid,authentic depiction of our contemporary life.He employs a narrative structure that overlaps the present with the past,blending tradition and modernity to create a truly magnificent epic.Rather than avoiding the contradictions and darkness inherent to humanity,the novel embraces them and strives to accurately depict their complexity,resulting in a more profound reflection on society.Above Baiyangdian Lake expands and innovates the path of local literature by applying a genuinely realistic approach.It not only surpasses Guan's writing style,but also represents a transcendence of local writing conventions in contemporary literature.It draws upon and elevates the literary tradition of the Hehuadian School,emerging as a notable example of new local writing with distinct regional traits.

The Light of Ideals and an Ambitious Regional"Epic" ——On Above Baiyangdian Lake by Guan Renshan

Above Baiyangdian Lake is another full-length realistic novel written by Guan Renshan after The Maihe River.In this work,Guan Renshan goes beyond traditional rural writing and artistically narrates the grand landscape of Baiyangdian New Area and the changes of people's fate during its construction.With Guan's refined and mature narrative techniques,the novel clearly shows his ambition to present a“regional epic.”This paper delves into the fictional text and analyzes the structuring method of Above Baiyangdian Lake from multiple perspectives such as its character shaping with historical correspondence,and narrative structure,skills,and style,aiming to provide an approach to interpret the ideological schema of Above Baiyangdian Lake.

Distribution of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) in surface water and sediments from Baiyangdian Lake in North China

Persistent organochlorine compounds, including hexachlorocyclohexanes （HCHs）, dichlorodiphenyltrichloroethanes （DDTs） and polychlorinated biphenyls （PCBs） were analyzed in surface water and sediments from Balyangdian Lake, North China. Total concentrations of HCHs, DDTs and PCBs in surface water were in the range of 3.13-10.60, 4.05-20.59 and 19.46-131.62 ng/L, respectively, and total concentrations of HCHs, DDTs and PCBs in sediments were 1.75-5.70, 0.91-6.48 and 5.96-29.61 ng/g dry weight, respectively. Among the groups of HCHs （sum of α-HCH, β-HCH, y-HCH and 6-HCH） and DDTs （sum of DDT, DDD and DDE）, the predominance of β-HCH, DDE and DDD in water and sediment samples was clearly observed. This observation suggested that β-HCH was resistant to biodegradation and the DDTs had been transformed to its metabolites, DDE and DDD. For PCBs, penta-, hexa- and hepta-chlorinated congeners were the most abundant compounds in the both phases. Furthermore, the partitioning of chlorinated compounds between sediment and water was investigated to understand their transport and fates in aquatic ecosystems. The results indicated that average logs of organic carbon-normalized sediment-water partition coefficients （logK∝） for OCPs varied between 3.20 and 5.53, and for PCBs, logK∝ values ranged from 3.19 to 5.57. The observed logK∝ was lower than their equilibrium logK∝ predicted from linear model, which may be attributed to the solubility enhancement effect of colloidal matter in water phase and the disequilibrium between sediment and water.

Distribution of polybrominated diphenyl ethers and decabromodiphenylethane in surface sediments from Fuhe River and Baiyangdian Lake,North China

Nineteen surface sediment samples collected from Baiyangdian Lake and its inflowing river （Fuhe River） in North China were analyzed for polybrominated diphenyl ethers （PBDEs） and decabromodiphenylethane （DBDPE）. The concentrations of PBDEs and DBDPE in sediments ranged from 5.5 to 300.7 ng/g dry weight （dw） and 1.1 to 68.2 ng/g dw, respectively. Their levels in sediments in Fuhe River were significantly higher than those in Balyandian Lake. Compared to data from other regions, the PBDE levels in surface sediments from Baiyangdian Lake and Fuhe River were in the medium to lower range. Among the PBDE congeners, BDE209 was predominant, with contributions to the total PBDEs ranging from 79.4% to 97.3% in sediment samples. For the lowly brominated congeners （tri- to hepta-BDE）, BDE47 and BDE99 were the most abundant, which contributed 52.1% and 44.1% to the sum of tri- to hepta-BDEs in the sediments from Baiyangdian Lake and Fuhe River, respectively. The compositional patterns of PBDEs in Baiyangdian Lake sediments indicated that technical deca-BDE mixture was the major pollutant sources with a minor contribution of penta-BDE mixture. The present study suggested that the importance of Fuhe River as a possibly potential sources of PBDEs contamination in Baiyangdian Lake.

Assessing the impacts of climate variability and human activities on streamflow in the water＇ source area of Baiyangdian Lake

As the largest wetland in the North China Plain （NCP）, the Baiyangdian Lake plays an important role in maintaining water balance and ecological health of NCP. Ir the past few decades, the decreasing streamflow in the Baiyangdian Basin associated with climate vari- ability and human activities has caused a series of water and eco-environmer,tal issues. In this study, we quantified the impacts of climate variability and human activities on streamflow in the water source area of the Baiyangdian Lake, based on analyses of hydrologic changes of the upper Tanghe river catchment （a sub-basin of the Baiyangdian Basin） from 1960 to 2008. Climate elasticity method and hydrological modeling method were used to distinguish the effects of climate variability and human activities. The results showed that the annual streamflow decreased significantly （P〉0.05） by 1.7 mm/a and an abrupt change was identi- fied around the year 1980. The quantification results indicated that climate variations ac- counted for 38%-40% of decreased streamflow, while human activities accounted for 60%--62%. Therefore, the effect of human activities played a dominant role on the decline of the streamflow in the water source area of the Baiyangdian Lake. To keep the ecosystem health of the Baiyangdian Lake, we suggest that minimum ecological water demand and in- tegrated watershed management should be guaranteed in the future.

Effect of Groundwater Level Fluctuation on Phragmites australis Evapotranspiration in the Baiyangdian Lake

Abstract:Hydrological regimes influence ecological patterns and processes as well as alter rates of wetland evapotranspiration.This study aimed to investigate the impact of groundwater fluctuation on evapotranspiration of Phragmites australis.Supported by field data obtained from the Baiyangdian Lake in northern China,the variations in groundwater levels were explored,and the changes in soil water and evapotranspiration of reed were analyzed to investigate different groundwater level scenarios using HYDRUS-1D model.The results showed that soil water content,recharged by groundwater,remained stable in the lower soil layer but varied strongly in the upper layer of the soil profile;in comparison to evaporation,Phragmites australis transpiration contributed significantly more to the overall evapotranspiration rate;the high levels of evapotranspiration could be maintained when groundwater levels vary between 1.0 m and 1.8 m,while it was reduced with an increase in groundwater levels as a result of water stress conditions.The results also indicated that the evapotranspiration of Phragmites australis could maintain higher evapotranspiration rates under natural water levels.The evapotranspiration,in other words,might be the main water consumer,but it nevertheless has little effect on water levels during water shortages.The evapotranspiration of Phragmites australis responded to the changes in groundwater levels could help researchers understand water requirements of the wetlands and establish suitable water levels for the wetlands.

A two-dimensional numerical model for eutrophication in Baiyangdian Lake

Hydrodynamic, physical, and biochemical processes in the Baiyangdian Lake water environment were analyzed comprehensively. An eutrophication eco- dynamics model including the effects of reed resistance on flow was coupled with the hydrodynamics governing equations. An improvement on the Water Quality Analysis Simulation Program （WASP, a modeling system intro- duced by the US Environmental Protection Agency） is established, which uses the zooplankton kinetic equation. The model simulates water quality constituents associated with eutrophication in the lake, including phytoplankton, zooplankton, nitrogen, phosphorus, dissolved oxygen, and others. Various kinetic coefficients were calibrated using measured data or information from relevant literature, to study eutrophication in the lake. The values calculated by the calibrated model agree well with field data, including ammonia nitrogen, total nitrogen, total phosphorus and dissolved oxygen. Changes related to nutrition and dissolved oxygen during the processes were simulated. The present model describes the temporal variation of water quality in Baiyangdian Lake with reasonable accuracy. Deviations between model-simulated and observed values are discussed. As an ideal tool for environmental management of the lake, this model can be used to predict its water quality, and be used in research to examine the eutrophication process.

Comprehensive analysis of nitrogen distributions and ammonia nitrogen release fluxes in the sediments of Baiyangdian Lake, China

The condition of Baiyangdian Lake(BYDL) will improve as the Xiongan New Area evolves and fulfills its role of easing overcrowding and supporting economic growth. Water and sediment samples from BYDL were analyzed to provide information on nitrogen(N) contamination in BYDL. The mean ammonium N(NH_4^+-N), nitrate N, and total N concentrations in the water samples were 0.36, 0.12, and 2.22 mg/L, respectively, and the ranges were 0.003–8.38, 0.06–0.30,and 1.25–10.34 mg/L, respectively. The N concentrations in water gradually increased from the north to the south of BYDL. Sediment at 90% of the sampling sites was in or above the moderately contaminated class(1000–2000 mg/kg) defined in US Environmental Protection Agency total N pollution standards. Positive NH_4^+-N fluxes were found for 28 of the 34 sediment core samples, so the potential for NH_4^+-N being released from sediment was relatively high. The NH_4^+-N fluxes were 5.35–48.76 mg/m^2/day, and the mean and maximum fluxes were 8.71 and 48.76 mg/m^2/day, respectively. Benthic organisms will be affected more by NH_4^+-N and NH_3·H_2O in the surface sediment pore water(mean concentrations 4.93 and 0.13 mg/L, respectively) than by the other forms of N.

Hydrochemical characteristics and geochemistry evolution of groundwater in the plain area of the Lake Baiyangdian watershed,North China Plain

Water cycle and water quality in the Lake Baiyangdian watershed of the North China Plain have undergone great changes due to over-pumping of groundwater and wastewater discharge.In this paper,hydrogeochemical data was collected to analyze the hydrochemical characteristics and geochemistry evolution of groundwater.The study area was divided into two typical parts.One was in the upstream plain area,where over-pumping had resulted in significant decline of groundwater level;the other one was located in the downstream area near the Fu River and Lake Baiyangdian(Lake BYD region).In addition to the natural weathering of minerals,excessive fertilizer was also a main factor of higher ion concentration in groundwater.According to studies,due to good permeability,these regions were easy to be polluted even with deep groundwater depth.However,upstream shallow groundwater and surface water,including lake water,domestic along with industrial wastewater were all sources of present shallow groundwater in the Lake BYD region.Results indicated that anthropogenic activities rather than minerals much matter to the groundwater in these regions.Particularly,wastewater largely decided the groundwater quality,which suggested that the management and restoration of surface water quality was crucial to groundwater protection.

Assessment of the Spatial and Temporal Water Eutrophication for Lake Baiyangdian Based on Integrated Fuzzy Method

Water quality evaluation entails both randomness and fuzziness. Considering that water eutrophication evaluation involves many indices, different classifications and interval values, fuzzy variable sets theory was developed to Lake Baiyangdian as a study case. Taking reference to eutrophication standard of Chinese lakes and local characteristic of Lake Baiyangdian, eutrophication degree of lake was divided into 8 levels. Total phosphorus, total nitrogen, and CODMn were selected as evaluation indices in this research. Based on the measured data, index feature value matrix of sample was built. Index weights were determined by means of pure threshold value method. Relative membership degree of each index to each classification was calculated with relative difference function model. Then the stability of feature value of classification corresponding was received by the comprehensive calculation with the relative membership degree and index weights. The results show that the proposed models are effective tools for generating a set of realistic and flexible optimal solutions for complicated water quality evaluation issues. It concluded that the model was reasonable and practical.

探地雷达在白洋淀湖底地层结构探测中的技术攻关与实践

白洋淀湖底地层调查对于白洋淀生态地质调查、湖底生态清淤及湿地生态保护具有非常重要的现实意义。为系统探明白洋淀湖底地层结构,从区域尺度对湖底地层实现完整刻画,为钻探调查提供精确的靶区数据支撑,创新了探地雷达应用范围,采用船载方式,透过水体开展了湖底地层勘查。剖析白洋淀湖底结构探地雷达勘探技术难点,分析了含底泥和不含底泥2种情形下水上勘探电磁波的传播特征和湖底原生地层的地球物理响应条件,建立了淀水+淤泥层+湖底原生地层的湖底简化结构模型。通过对比国内外主流探地雷达系统不同硬件设备的勘探能力与适应条件,优选出双皮划艇搭载50 MHz低频组合天线的工作模式,结合适用于水下电磁波弱信号提取的数据处理技术,获得了白洋淀湖底15 m深度范围的地层结构数据。结果表明,此种工作模式适用于湖区水深小于5 m的水域,原生地层电磁波整体呈现弱反射特征,湖底15 m深度范围内存在2~3组砂层反射界面。淤泥层会大大削弱湖底原生地层的电磁波反射强度。存在厚砂层的水域,电磁波会形成强反射波组,砂层展布形态刻画清晰,砂层厚度变化在0~3 m之间。本项研究实现了湖底地层结构建模分析、天线勘探模式优选、数据处理过程优化等技术集成。该技术成果为白洋淀淀区地下水与地表水三维地质建模提供了基础依据,为湖底地层钻探勘查提供了靶区支撑,有力推动了白洋淀湿地水-陆一体化探测技术方法体系的构建。

白洋淀浮游生物群落结构及关键环境因子分析

浮游生物对环境变化敏感,可作为环境监测的指示生物。2021年9月,采用冗余分析法、相关性分析法对白洋淀浮游生物及关键环境因子进行研究。共鉴定出浮游动物47种,优势种为无节幼体、近邻剑水蚤、萼花臂尾轮虫、螺形龟甲轮虫、针簇多肢轮虫、曲腿龟甲轮虫、长额象鼻溞、卜氏晶囊轮虫;共鉴定出浮游植物143种,优势种为小球藻、梅尼小环藻、席藻和尘埃微囊藻。分析结果表明:浮游动物多样性指数与环境因子之间的相关性不显著;浮游植物多样性指数与总氮含量、pH、化学需氧量、亚硝态氮含量显著相关;pH、化学需氧量是影响浮游动物群落分布的主要环境因子,亚硝态氮含量、pH、总氮含量是影响浮游植物群落分布的主要环境因子。pH、化学需氧量、亚硝态氮含量、总氮含量及浮游生物多样性指数可作为白洋淀水质状况的重要评价指标。

湖泊环境因子空间异质性及其对食物网结构的影响研究——以白洋淀为例

湖泊环境因子变化会影响食物网和生态系统结构。为了明晰湖泊环境因子空间变化对食物网结构的影响,本研究选取白洋淀为研究区,分别于2018年4月(春季)和8月(夏季)采集水体、沉积物和生物样品。淀区共设置32个采样点,根据土地利用类型划分为3个不同区域:重度干扰区(生境1)、中度干扰区(生境2)和轻度干扰区(生境3)。本研究分析了水体、沉积物的主要理化因子和食物网结构的时空变化,利用模糊聚类法阐明环境因子空间变化对食物网结构的影响,运用空间自相关分析环境因子的空间异质性,利用典范对应分析(canonical correspondence analysis,CCA)和偏最小二乘回归分析识别影响食物网结构的关键环境因子。结果表明:(1)就物理生境条件而言,水深(water depth,WD)、pH、温度(temperature,T)、透明度(transparence,Tran)和溶解氧(dissolved oxygen,DO)最大值均在生境3;而就水化学条件而言,总氮(total nitrogen,TN_(sediment))、总磷(total phosphorus,TP_(sediment))和总有机碳(total organic carbon,TOCs)最大值均在生境2;(2)模糊聚类分析表明,环境因子数值越大,食物网结构特征指数越低,食物网结构越不稳定;(3)空间自相关分析表明,T、Tran、pH和化学需氧量(chemical oxygen demand,COD)莫兰指数分别为0.14、0.10、0.44和0.37,其值呈现正相关,在空间上形成高低聚类;(4)CCA和偏最小二乘回归分析结果表明,WD、TP_(water)、TN_(sediment)和T是影响白洋淀食物网结构的关键环境因子。因此,在全球气候变化和快速城市化背景下,应重点监测T、WD和营养盐。

白洋淀上游流经城区前后细菌群落结构和功能与环境因子的关联研究

细菌群落作为水生态环境的重要组成部分,其结构和功能研究可为水生态环境污染监测与治理提供技术支撑。通过对流经城区白洋淀上游河流细菌群落的高通量测序和环境因子的监测,分析城市环境因素对白洋淀上游水质的影响,并深入探究细菌群落功能与污染物动态变化的关系。结果表明,城市环境对白洋淀上游生态环境的影响较大,上、中、下游的水质等级差异显著。城区中汇入的各类污染物不仅影响细菌群落结构,使得污染严重流域高丰度的细菌种群减少和细菌群落多样性增加;还与细菌群落的硝酸盐和磷酸盐代谢功能密切相关。同时,河流虽汇集了城区的各类污染物,但下游的细菌群落结构和部分氮、磷代谢功能均有恢复为上游水平的趋势。此外,高丰度的黄杆菌属(Flavobacterium)受各类菌群和污染物的抑制作用较大,但验证其与NO-3-N污染物具有较强的相关性。对白洋淀上游流经城区前后细菌群落结构和功能与环境因子动态变化的关联研究,为白洋淀流域生态环境保护与污染治理提供理论依据。