Plio-Pleistocene climate variability in East Asia has been studied intensively using Chinese loess deposits and marine records from the South China Sea. However, long-term climate trends since the late Pliocene remain controversial due to the different sensitivity of proxy indicators to temperature and precipitation changes. Here, we present high-resolution elemental compositions of two high-quality fluvial sequences in the Eastern Henan Basin that reflect significant hydroclimate fluctuations over the last -3.5 Ma. Multivariate statistical analysis of ten elements (Si, K, Ca, Ti, Mn, Fe, Rb, Sr, Zr, and Ba) showed that the first principal component (PC1) includes detrital elements of Si, K, Ti, Mn, Fe, and Rb demonstrating significant fluctuations similar to the Ti/K ratio. The second principal component (PC2) includes Ca, Sr, and Ba, whose fluctuations match well with the Ca/K ratio. Combining the sedimentary facies and grain size analysis, we concluded that PC1 mainly reflects the hydrodynamics related to the summer monsoon while PC2 is associated with the dry-wet alternation induced by temperature and precipitation. Variations of PC1, PC2, and climate-sensitive elemental ratios demonstrated a multistage climatic evolutionary pattern, shifting from relatively humid climate conditions during the late Pliocene (3.5-2.8 Ma) to relatively dry conditions during the early Pleistocene (2.8-0.9 Ma), followed by the latest humid climate after 0.9 Ma. Our elemental results suggested that the hydroclimate changes of the Eastern Henan basin are mainly affected by the stepwise evolution of the East Asian summer monsoon.

In recent years, geological disasters on loess fill slopes have occurred from time to time, which has attracted widespread attention. In order to deeply understand its deformation and failure laws and promote the disaster prevention and mitigation work, this paper takes remolded loess as the research object, systematically explores the effects of three different stress paths (conventional triaxial compression test (CTC), triaxial compression test with constant average principal stress (TC), and triaxial compression test with reduced confining pressure (RTC)) on its mechanical properties, and observes and analyzes its microstructural characteristics by scanning electron microscopy (SEM). The results show that the soil is strain hardening under the CTC path, while it is strain weak hardening under the TC and RTC paths. In the order of CTC, TC, and RTC paths, the shear strength and volume shrinkage of the soil are reduced in turn, and its deformation has both shear reduction and shear expansion plastic deformation. In the order of CTC, TC, and RTC paths, the degree of particle crushing decreases in turn and the pore content increases in turn. It is inferred that in the initial deformation of loess under loading, the soil is compressed and compacted, and its strength is improved to a certain extent. As the loading continues to increase, the deformation rate increases steadily, and the soil deformation develops gradually, which is mainly axial compression deformation, while the lateral bulging deformation is small until it is destroyed. For the deformation behavior in the form of lateral unloading, the soil is maintained in a relatively stable state at the beginning, and the deformation is very small. When the lateral constraint is reduced to a critical state, the structure is completely unstable, and the deformation develops rapidly in a short time until it is destroyed. This study is of great significance for reducing the occurrence of geological disasters on fill slopes in loess areas.

[Objective]The mountainous and hilly areas of western Zhengzhou City have a complex geological environment,affected by rainfall and human engineering activities.Geological hazards such as collapses,landslides,and debris flows occur frequently.In particular,the"7·20"extreme rainstorm that occurred on July 20,2021 caused many geological hazards,resulting in heavy casualties and huge economic losses.Therefore,analyzing and summarizing the development characteristics of geological hazards and conducting a risk assessment is necessary for this region.At present,the risk assessment of geological hazards is mainly conducted using a single method that has limitations including slightly low evaluation accuracy.In addition,an overall geological hazard risk assessment has not yet been conducted in the mountainous and hilly areas of western Zhengzhou City.[Methods]Based on the research and analysis of the geological environment background and the distribution characteristics of geological hazards in the study area,eight evaluation factors were selected:slope,landform,engineering geological rock group,elevation,distance from fault,distance from river,rainfall,and human engineering activities.The weighted information method which incorporates elements of the information quantity model and analytic hierarchy process,was used to evaluate the risk of geological hazards in the study area.[Results]The low-,medium-,and high-risk areas are 1387.14 km2,1803.18 km2,and 1066.47 km2,respectively,accounting for 32.59%,42.36%,and 25.05%of the total area,respectively.The medium-and high-risk areas are mainly distributed in the tectonic erosion medium-low mountains and loess hills in the central part of the four cities,the tectonic erosion medium-low mountains south of Dengfeng,and the loess hilly areas in northern Gongyi and Xingyang.The terrain has steep slopes and deep gullies,and the main stratigraphic lithology is clastic rocks intercalated with carbonate rocks,soft and hard rock layers,and loess.Fault structures are developed,and geological hazards are prone to occur under the action of inducing factors and are highly dangerous.The majority(93.11%)of geological hazards are distributed in medium-and high-risk areas,with hazard point densities of 0.1752 km-2 and 0.2869 km-2,respectively.The spatial distribution of geological hazard points is consistent with the geological hazard risk assessment results.The rationality of the evaluation results was assessed by a Receiver Operating Characteristic curve,yielding an AUC value of 0.868.The evaluation accuracy met the requirements for hazard assessment.[Conclusion]Geological hazards have the largest information value in the range of>40°slopes loess hilly landforms,loess engineering geological rock groups,and 24-h maximum rainfall of 500-550 mm.The risk of geological hazards is positively correlated with distance from faults and water systems—the closer the distance,the higher the risk.The risk of geological disasters in the study area is controlled by the terrain slope and landform and is closely related to the lithology of the formation,which is an important factor in inducing geological disasters.The weighted information method,which has high accuracy and rationality,was used to evaluate the geological hazard risk.[Significance]The results of this study can provide a basis and technical support for geological hazard prevention and management in the mountainous and hilly areas of western Zhengzhou City and serve as a valuable point of reference for urban planning and infrastructure geological hazard risk assessment in the study area.

The Eastern Henan Basin is situated within the downstream alluvial plain of the Yellow River, harboring an impressive accumulation of over 500 m of fluviolacustrine strata since the Pliocene. However, the evolutionary characteristics and driving factors of the sedimentary environment in this region remain unclear due to a lack of reliable chronological constraints on the sedimentary sequence. Here, two cores were retrieved from Hangkonggang (HKG, 303.5 m) and Baisha (BS, 320.2 m) in the Eastern Henan Basin for comprehensive analyses of chronology and sedimentology. A combination of paleomagnetism, electron spin resonance (ESR), and optically stimulated luminescence (OSL) dating results indicates that sediments of two boreholes were accumulated spanning the last 3.48 Ma. Grain size distributions (GSDs) of typical sedimentary facies show that the boreholes predominantly encompass three types of sedimentary facies: riverbed, levee, and floodplain. Downcore variations of mean grain size (MGS) reveal that the sedimentary environment in this basin evolved from a dominant riverbed setting during the late Pliocene (3.48-2.72 Ma) to alternations between the floodplain and levee facies during the early Pleistocene (2.72-1.25 Ma) and subsequently between the riverbed, levee, and floodplain after 1.25 Ma. It was closely associated with the decrease in East Asian monsoon precipitation at 2.72 Ma and the increase at 1.25 Ma. Notably, the abrupt coarsening of MGS after 1.25 Ma was synchronized with the formation of the Sanmenxia terraces, implying the significant influence of the evolution of the Yellow River. Our results suggest that the sedimentary environment of the Eastern Henan Basin was predominantly affected by the stepwise evolution of the East Asian monsoon since 3.48 Ma and complementary landform transformation of the Yellow River since at least 1.25 Ma.

With the rapid socio-economic development and urban expansion, land subsidence has emerged as a major environmental issue, impeding the high-quality development of the plain area in eastern Zhengzhou City, Henan Province, China. However, effective prevention and control of land subsidence in this region have been challenging due to the lack of comprehensive surface deformations monitoring and the quantitative analysis of the factors driving these deformations. In order to accurately identify the dominant factor driving surface deformations in the study area, this study utilized the Persistent Scattered Interferometric Synthetic Aperture Radar (PS-InSAR) technique to acquire the spatio-temporal distribution of surface deformations from January 2018 to March 2020. The acquired data was verified using leveling data. Subsequently, GIS spatial analysis was employed to investigate the responses of surface deformations to the driving factors. The findings are as follows: Finally, the geographical detector model was utilized to quantify the contributions of the driving factors and reveal the mechanisms of their interactions. The findings are as follows: (1) Surface deformations in the study area are dominated by land subsidence, concentrated mainly in Zhongmu County, with a deformation rate of −12.5–−37.1 mm/a. In contrast, areas experiencing surface uplift are primarily located downtown, with deformation rates ranging from 0 mm to 8 mm; (2) Groundwater level, lithology, and urban construction exhibit strong spatial correlations with cumulative deformation amplitude; (3) Groundwater level of the second aquifer group is the primary driver of spatially stratified heterogeneity in surface deformations, with a contributive degree of 0.5328. The contributive degrees of driving factors are significantly enhanced through interactions. Groundwater level and the cohesive soil thickness in the second aquifer group show the strongest interactions in the study area. Their total contributive degree increases to 0.5722 after interactions, establishing them as the primary factors influencing surface deformation patterns in the study area. The results of this study can provide a theoretical basis and scientific support for precise prevention and control measures against land subsidence in the study area, as well as contributing to research on the underlying mechanisms.

Objectives: The rock—soil strata constitute the basic material environment of the underground space and have a huge impact on the development and utilization of the underground space. Therefore, in-depth understanding and analysis of the structural characteristics of the rock—soil strata can lay a solid foundation for the development of the underground space.Methods: The urban area of Zhengzhou mainly distributes loose strata such as silt, silty clay, clay, silty sand, medium—coarse sand, and some special soils such as soft soil and collapsible loess. According to the vertical combination of rock and soil strata, it is divided into single-layer structure, double-layer structure, triple-layer structure and multiple-layer structure. Then, the stratigraphic structure of the underground space in Zhengzhou urban area is discussed separately according to the shallow layer（0～-15 m）, the sub-shallow layer（-15～-30 m） and the sub-deep layer（-30～-50 m）.Results: The shallow（0～-15 m） underground space stratigraphic structure in Zhengzhou City is divided into 3 regions, 6 sub-regions and 25 structural sections; the sub-shallow（-15 ～-30 m） underground space stratigraphic structure is divided into 2 regions and 28 sub-regions; the sub-deep（-15 ～-30 m） underground space stratigraphic structure is divided into 2 regions and 31 sub-regions. It provides accurate geological data and technical support for the development and utilization of underground space in Zhengzhou city.Conclusions: The overall structure of the underground space in Zhengzhou is relatively simple, the cost and risk of development are low, and it has great potential for development and utilization. Overall, the western piedmont alluvial and diluvial plain area is more suitable for underground space development and utilization than the eastern Yellow River alluvial plain area.Based on the stratigraphic structure characteristics of different urban areas, the following suggestions for the development and utilization of underground space are put forward: focus on the development and construction of underground storage and underground energy production facilities in the western new urban area; build underground water storage pipe gallery and deep drainage in the main urban area; north of the Lianhuo Expressway in the eastern new urban area as an avoidance area for underground space development; the Aviation city focuses on the construction of underground storage, modern logistics channels and other facilities. And the influence of stratigraphic structure on the construction of sponge city and road collapse in Zhengzhou is discussed.

Soil structure at the basin scale affects the superficial moisture content, heat, salinity balance, and ecological balance of groundwater system. To study the soil particle size fractal characteristics at the basin scale, 188 groups of soil samples were collected over a distance of 258 km in the Ziya River basin of the North China Plain. Particle volume percent was measured using a laser particle size analyzer, and then analyzed by applying the fractal theory to reveal the spatial distribution of soil particle size and soil voids. The results showed that: (1) From the Taihang Mountain piedmont to the coastal area, soil particle-size volume percentages varied in a small range, with the fractal dimension D showing an overall decreasing trend; (2) D showed a significant spatial variation, ranging from 0.13 to 2.188. It was jointly determined by particle uniformity and particle size range; (3) When D ≤ 1, the characteristic fractal size was 30 μm in the basin. When 1 < D ≤ 1.5, the characteristic fractal size was 20 μm and D a was 1.37, and when D > 1.5, the two parameters were 10 μm and 1.77, respectively. The research results indicated that D can effectively quantify the characteristics of soil structure at a large scale.

地下水是维持人类生存和发展的重要资源.近年来,由于人类活动的强烈干扰,导致地下水的水化学特征发生改变,严重影响了其使用价值和生态功能.本研究以郑州市中牟县作为研究地区,联合应用Piper三线图、Gibbs图、离子比例系数法和多元统计技术,探究该地区地下水化学演变特征及形成机制,结果表明,中牟县地下水主要的阳离子是Ca2+和Na+,主要的阴离子是HCO3-和Cl-.地下水主要的水化学类型为HCO3-Ca(Mg)型,占总水样的46.2％.农业用地受到施肥的影响,水化学类型出现了Cl型水(20.8％)和SO4型水(6.25％),住宅用地由于受到生活污水的影响,出现了高比例的Na型水(55.0％).而在湿地,地下水受到黄河水和污水处理厂回水混合影响,导致其主要的水化学类型转变为HCO3-Ca(Mg)·Na型.中牟县地下水水化学组分主要控制因素是岩石风化作用,并且主要受控于硅酸盐岩风化,而人类活动对水化学组分也存在一定的影响.相关性分析表明,在不同土地利用类型下,除NH4+、NO3-和NO2-外,其余水化学组分之间表现出显著的正相关关系,表征它们主要来自地层岩石风化.NH4+和NO3-表现出显著的负相关关系,说明二者主要来自于化肥和生活污水.在农业用地和住宅用地中地下水可能发生强烈的硝化作用,但是,湿地地下水可能发生了反硝化作用.研究结果可为中牟县地下水可持续开发利用提供理论依据和数据支撑.

A large number of antibiotics have been discharged into rivers by human activities, posing a threat to aquatic ecosystems. The surface water of the Yellow River Basin also suffers antibiotic pollution, which hinders the improvement in the aquatic ecological environment. This study investigated and analyzed the characteristics and assessed the ecological risks of antibiotic pollution in surface water bodies such as canals, rivers and fish ponds in Kaifeng, Henan Province, which is a key city along the lower reaches of the Yellow River. The test results are as follows. A total of 15 types of antibiotics were detected in the surface water. They had a total antibiotic concentration of 12.2?249.9μg/L, of which tetracyclines (TCs) and quinolones accounted for the highest percentages. Six types of quinolones had detection rates of up to 100％, and doxycycline (DC) and oxytetracycline (OTC) had average concentrations of 29.52μg/L1 and 13.71 μg/L, respectively. The major canals with water diverted from the Yellow River had total concentrations of quinolones and TCs of 22. 0μg/L and 14.9μg/L, respectively, which were higher than those in previous studies. This phenomenon may be related to the decrease in the water flow of the Yellow River during the dry season and the increase in the antibiotic consumption of residents in the context of the Covid-19 outbreak. The upper reaches of the Huiji River in the Xiangfu District had higher antibiotic content than other districts in Kaifeng. Specifically, TCs accounted for 72.38％?91.84％of all antibiotics, and the DC and OTC concentrations were significantly higher than other antibiotics in the upper reaches. As indicated by the ecological risk assessment results, TCs had the highest ecological risks to green algae. Among them, DC had medium-high risks;TC, OTC, and chlortetracycline (CTC) had medium-high risks;trimethoprim (TMP) and lomefloxacin (LOM) had low risks;other TC antibiotics had no risk. Compared with green algae, most antibiotics showed higher ecological risks to daphnia and lower ecological risks to fish. DC and OTC dominate antibiotic pollutants in the surface water in Kaifeng City, and especially in Xiangfu District, where DC and OTC have medium-high risks. The TCs in the major Yellow River showed medium risks to both green algae and daphnia. It can be speculated that the antibiotic pollution in the Yellow River might pose a certain threat to the ecological security of water in Kaifeng City.

城市地下空间开发利用是目前解决城市发展瓶颈的有效途径,其三维地质模型的构建是目前研究的热点和难点.本文基于稀疏实测钻孔的分布特征,采用空间 自协方差插值法、尖灭点处理算法及Loop细分算法,生成插值加密虚拟钻孔、尖灭处理虚拟钻孔及细分光滑虚拟钻孔,然后基于实测钻孔和虚拟钻孔,运用Civil 3D平台的地质建模功能,快速构建出符合地统计学规律的、反映研究区现场地层信息的三维地质模型,实现地质信息的直观可视性、兼容性以及可编辑性,为建立城市地下空间开发利用中通过三维地质模型获取地质信息提供新方法.

大兴安岭南段长期矿产开发对该地区河流生态环境造成了巨大压力,评估河流沉积物中重金属的污染状况及潜在生态风险对该地区河流生态环境保护具有重要意义.以大兴安岭南段某铅锌矿区为研究区,在流经矿区河流的上、中、下段沿流向采集了6组表层沉积物样品,测试了其中19种金属与主量元素的含量,通过相关性和聚类分析确定了受主要影响的重金属元素,利用土壤环境质量标准和沉积物质量基准对重金属的含量特征进行了评估,并进一步采用地质累积指数(Igeo)和潜在生态风险指数(Iperi)对重金属的污染程度和潜在生态风险进行了评价.结果表明,(1)研究矿区河流沉积物中As、Cd、Cu、Pb、Zn、CaO与MnO含量两两之间呈显著正相关,Pearon相关系数均大于0.85,Ward系统聚类分析属于一类,指示这些元素在沉积物中很可能具有相似的来源.7种元素在沉积物中的含量均大于其背景值,且变异系数较大(>60％),表明其含量受矿山开发活动影响显著.(2)沉积物各采样点的Cu含量均低于土壤污染风险筛选值(RSV)和临界效应浓度(TEL).河流上、下段沉积物的As、Cd、Pb、Zn含量均低于RSV,中段的含量均高于RSV,其中As、Pb、Zn含量高于可能效应浓度(PEL).(3)沉积物重金属的Igeo从小到大依次为Cu<As<Zn<Pb<Cd,Cd的Igeo为4.29,属重度污染等级.重金属的潜在生态风险因子(Er)从小到大依次为Cu<Zn<As<Pb<Cd,Cd的Er为2633.69,属极高风险等级,占Iperi的81.21％—91.65％,表明Cd是沉积物的主要污染和风险来源.(4)河流中段沉积物重金属元素属偏中度-严重污染等级,其Iperi高达5619.87,属极高风险等级,污染程度和生态风险都明显高于上、下河段,表明河流中段受矿山开发活动的影响最为显著.

河南郑州"7?20"特大暴雨后,城市内涝灾害如何防范,海绵城市如何发挥减灾作用广受关注.郑州是全国首批开展多要素城市地质调查的示范城市之一.中国地质调查局与河南省自然资源厅、郑州市政府构建联动机制,在"空间、资源、环境、灾害"等方面统筹部署地质调查工作,为该市规划、建设、运行和管理提供自然资源和地质环境保障.

城市建筑基础占用了大量的地下空间资源,这部分空间资源的三维分布信息对城市地下空间利用规划必不可少.但这方面的信息往往分散在各个工程建设机构中,不易获取.为解决建筑基础占用地下空间信息难以获取的问题,需探索出一种高效准确的探测技术.通过参考建筑地基基础计算方法,研究出一种建筑地基基础占用空间的测算方法:采用高分辨率遥感信息探测获取地面建筑相关参数,收集分析工程地质勘察资料获取相关岩土参数;将遥感探测、工程勘察获取的参数与建筑基础占用空间的测算方法结合,形成了一套用于测算建筑地基基础占用空间的遥感解译-地质工程相结合的探测技术.在郑州航空港区应用结果表明,该技术操作方便、高效快捷、探测结果准确,能够满足地下空间利用规划需要,有广阔的推广应用前景.

较为客观地评价城市地下空间开发适宜性,是科学合理有效利用城市地下空间的前提和依据.提出熵权-层次分析法以实现权重的客观分析计算,综合考虑影响城市地下空间开发的主要地质因素,采用层次分析法建立评价指标体系,运用模糊综合评判法评价地下空间开发适宜性,并使用ArcGIS生成地下空间开发适宜性分区图.评价结果表明,郑州市地下空间开发非常适宜区占研究区面积的22.64％,适宜区占34.41％,一般适宜区占35.90％,不适宜区占7.05％.该评价结果较为客观、合理,可以为郑州市地下空间开发整体规划提供参考.

海绵城市规划建设过程中,自然及地质背景条件对低影响开发设施的布设具有重要影响.针对郑州市的1945 km2海绵城市规划区,根据海绵城市建设要达到的蓄水、渗水、净水等功能,分析地表植被、地形坡度、包气带及含水层等海绵特性,构建了基于海绵城市建设的地质适宜性评价体系,并用层次分析法进行评价,结果表明:郑州市海绵城市建设地质适宜性好的区域面积占规划区的3.83％,适宜性较好区域占33.12％,适宜性中等区域占54.05％,适宜性差区域占9.00％;郑州市规划的12个海绵城市重点建设区,有2个覆盖不适宜建设区,分布在龙湖片区西北部和双鹤湖片区;航空港区有建设海绵城市的天然条件,建议在东湖节点周围规划海绵重点建设区.海绵城市建设的地质适宜性评价结果对郑州市海绵城市规划建设有参考意义.

Fluoroquinolone antibiotics in soil can cause serious antibiotic pollution. Adsorption is the main factor that influences their destination and transport of antibiotics. Therefore, research on the behaviour of antibiotics once they reach the soil environment is meaningful to design appropriate measures to reduce their potential risks. This research took levofloxacin (LVFX) as the research object and used a static adsorption experiment to study the adsorption behaviour of the vadose zone of silty clay on the North China Plain. The results showed that LVFX had high retention in silty clay, with an average adsorption ratio of more than 90%. Adsorption of LVFX on silty clay reached equilibrium in 24 h with an adsorption amount of 93.5 mg/kg at an initial LVFX concentration of 10 mg/L. Acidity, cations and soil organic matter could affect the adsorption of LVFX, with adsorption variation ratio of 3.3%, 3.4% and 0.6%, respectively. In addition, numerical simulation with Hydrus-1D was utilized, and the results show that LVFX may infiltrate into underground water through silty clay after 28 days and completely penetrate in 100 days.

论文以华北平原某垃圾场为例,选取低环萘(2环)和高环苯并[ghi]苝(6环)即迁移能力最强与最弱的两类多环芳烃的代表性物质为研究对象,采用0.01mol/LCaCl2溶液与垃圾渗滤液两种背景溶液,通过试验分析黏性土对多环芳烃吸附动力学、等温吸附性,揭示出垃圾渗滤液中多环芳烃在包气带黏性土中吸附规律和机理,这一研究对探讨黏性土吸附垃圾中多环芳烃的阻隔规律和地下水污染防治具有重要意义.

第四系松散地层对工程建设、城市发展等影响较大,一些地区的沉积环境较复杂,给划分了解其地层层序变化带来很大困难.借助有限测年资料等,仅能反映样点附近情况,且费用很高.以郑州航空港北部一带为例,在深入分析其地质调查资料并结合对周边地质环境的成熟认知,以及现有关于第四纪时代划分与冷、暖气候变化认识等基础上,改进了一套由一系列关键划定步骤接续组成的,以侧重反映地层成因、岩性特征、沉积旋回变化,并含括地质构造运动、气候变化、地层年代信息等内容的地层层序划定方法,解决了上述难题.新方法划定结果符合区域地质环境的演进特征.一些特征明显的地层可在认识成熟的周边地区或地层组中找到印证,连同其他重要地质信息,可基本控制满足地层划分对地质年代的精度要求.

为了研究内蒙古赤峰市巴林左旗白音诺尔铅锌矿区采矿对哈力黑河生态环境造成的影响,从上游向下游采集了6个河流沉积物样品,测定其pH、LOI、粒度以及As、Cu、Pb、Zn、Cd等5种重金属的总量和赋存形态,并对测试结果进行分析.研究结果表明:(1)1#尾矿库是造成沉积物中Pb、Zn和Cd等重金属显著升高的主要原因.(2)沉积物重金属与粗粉砂(16～63 μm)的相关系数为0.79 ～0.95,表明重金属易富集于粗粉砂上,而沉积物的pH和有机质对重金属总量的变化影响不显著.(3)沉积物中As和Pb以残渣态和铁锰结合态为主,分别占总量的78.82％～89.87％和36.96％～78.20％.Cu和Zn以残渣态、强有机结合态和铁锰结合态为主,分别占总量的76.38％ ～ 85.96％和74.94％ ～ 90.34％.Cd则以离子交换态、碳酸盐结合态和强有机结合态为主,占总量的51.15％ ～ 79.53％,而离子交换态Cd占了总量的5.72％ ～49.63％.因此,Cd对河流生态环境的潜在威胁最大.(4)离子交换态Cd与沉积物pH相关系数为-0.813,两者呈极强负相关性.当沉积物pH由弱酸性转化为弱碱性时,离子交换态Cd含量从33.44％降低至5.72％,显著减小.

There are about 800000 km2 carbonate formation, 3620 karst groundwater systems and 1806×108 m3/a karst water resources in southern China, which supply water for about 50 million urban residents and more than 8000 rural people in 69 cities of southern China. However, karst water has been polluted in different degrees, and the agricultural areal source pollution is far more serious than the non-areal source pollution for karst water, which will threaten the water supply security in karst areas. Therefore, the risk assessment study of karst groundwater pollution is of great significance. Based on comprehensive and systematic analysis of the characteristics, the pollution types and pollution ways of southern China's karst water, and consulting the existing experimental results, the authors summarized the protective capability against pollution of karst ground water, and proposed the methods for pollution risk identification, the pollution probability estimation, the pollution risk assessment and control. With Guiyang as an example, the authors evaluated the karst groundwater areal source pollution risk, and put forward prevention and control countermeasures according to the characteristics of the karst groundwater areal source pollution.