To investigate the presence of metal elements and assess their health risk for the populace in the Nandong Underground River Basin (NURB), we conducted an analysis of eleven common heavy metals in the water body. A Health risk assessment (HRA) model was employed to analyze 84 water samples from the NURB. The detection results revealed the following order of heavy metals concentrations: Fe > Al > Mn > Zn > As > Cd > Pb > Cr > Ni > Cu > Hg. Correlation analysis indicated a certain similarity in material source and migration transformation among these eleven metal elements. Our study identified that the health risks for local residents exposed to metal elements in the water of NURB primarily stem from carcinogenic risk (10−6–10−4 a−1) through the drinking water pathway. Moreover, the health risk of heavy metal exposure for children through drinking water was notably higher than for adults. The maximum health risks of Cr in both underground and surface water exceeded the recommendation standard (5.0×10−5 a−1) from ICRP, surpassing the values recommended by the Swedish Environmental Protection Agency, the Dutch Ministry of Construction and Environment and the British Royal Society (5.0×10−6 a−1). The results of the health risk assessment indicate that Cr in the water of NURB is the primary source of carcinogenic risk for local residents, followed by Cd and As. Consequently, it is imperative to control these three carcinogenic metals when the water was used as drinking water resource.

Wastes from social economic activities had great impact on water quality thereby limiting water usability for domestic purposes. Sewages discharge from people activities, usually consist of undesirable concentrations of soluble chemicals that infiltrate into the surrounding surface and underground water, and then constitute health risk to the populace. In order to investigate the concentration characteristics and health risk for the local residents in Nandong Underground River Watershed (NURW), eleven common heavy metals in the water body analysis were conducted. Health risk assessment (HRA) was taken to analyze eleven heavy metals of 84 water samples from surface and underground waters in NURW: 36 samples underground water and 48 samples surface water. Our results showed that the heavy metals concentration order is that of Fe > Al > Mn > Zn > As > Cd > Pb > Cr > Ni > Cu > Hg. Correlation analysis indicates that these eleven metal elements have certain similarity on material source and migration transformation. The health risks for local residents exposed to metal elements in the water of NURW mainly from carcinogenic risk (10−6～10−4 a−1) through drinking way, and the health risk of heavy metals exposed to children through drinking way was much higher than adults. The maximum exposing health risks of Cr in both underground and surface water were higher than the recommendation standard (5.0×10-5 a-1) from ICRP, and all the values over the standard (5.0×10-6 a-1) recommended by the Swedish Environmental Protection Agency and the Dutch Ministry of Construction and Environment and the British Royal Society. The results of health risk assessment shows that Cr in the water of NURW was the mainly source of carcinogenic risk for the local residents, following by Cd and As. Consequently, it is necessary to control the three carcinogenic metals when the water was used as drinking water source.

The karst surface water and groundwater of Nandong underground river basin are vital water sources for agricultural and industrial production, and lives of residents in Honghe Hani and Yi Autonomous Prefecture in Yunnan, Southwest China. With a growing public awareness of water environment and water safety, the evaluation of karst water quality and irrigation applicability especially in agricultural regions is becoming increasingly necessary. In this study, 32 samples of karst surface river water and 24 samples of underground river water were collected from Nandong underground river basin during dry and rainy seasons. 11 inorganic regular ions (i.e., K+, Na+, Ca2+, Mg2+, Cl−, \begin{document}${\rm{SO}}_4^{2-}$\end{document}, \begin{document}${\rm{HCO}}_3^{-}$\end{document}, \begin{document}${\rm{NO}}_3^{-}$\end{document}, NO\begin{document}$_2^{−}$\end{document}, NH\begin{document}$_4^{+}$\end{document}, and F−) and 9 heavy metals (i.e., Al, Cu, Pb, Zn, Cr, Cd, Ni, Mn, and As) were analyzed in these samples to investigate the water quality and irrigation applicability. Based on the measured concentrations of the hydrochemical composition, the Nemerow composite index in combination with the four irrigation assessment systems of sodium concentration (SC), sodium adsorption ratio (SAR), residual sodium carbonate (RSC), and permeability index (PI) were applied to evaluate the karst water quality and irrigation applicability, respectively. Results show that Ca2+ and \begin{document}${\rm{HCO}}_3^{-}$\end{document} were identified as the major ions in both karst surface water and karst groundwater, indicating weakly alkaline karst water in the study area. For karst surface water, among the 11 inorganic regular ions, only NH\begin{document}$_4^{+}$\end{document} was found exceeding the maximum acceptable level for drinking water recommended by General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China. Meanwhile, among the 9 heavy metals, the concentrations of Al, Pb, Mn, and As were evaluated as exceeding the maximum acceptable level. Moreover, the rates of measured ions exceeding permitted levels in the dry season were generally higher than those in the rainy season. For karst groundwater, the concentrations of Al, Pb, Zn, Cr, Mn, and As exceeded the maximum acceptable levels, and the rates of these metals exceeding permitted levels in the rainy season were generally higher than those in dry season. The nitrogen synthetic fertilizers might be a main cause of the increase of NH\begin{document}$_4^{+}$\end{document} concentration in karst surface water. High concentration of Al, Mn, and Cd in karst water were mainly caused by large amounts of discharge from metal smelting, waste residue of mining, and open-pit mining. Furthermore, an exposed surface environment of bedrock in some parts of this study area might be responsible for these components exceeding the permitted levels due to the lack of surface decontamination of pollutants. The karst water quality belonging to the good grade or above accounted for 89.29% and 85.71% of the total water samples collected during the dry season and the rainy season, respectively, and the quality belonging to poor grade or below accounted for 7.14% and 14.29%, respectively. Hence, the karst water quality in Nandong underground river basin was generally high based on the results of the assessment of karst water quality. However, some cases of poor-quality karst water were found in parts of our study area (e.g., G1 and S4 sampling sites in the dry season and G1, G2, and G3 sampling sites in the rainy season), accompanied by the seasonal differences in karst water pollution. According to the permitted level for irrigation water and the results of SC, SAR, RSC, and PI assessments, most of the karst water in Nandong underground river basin was generally suitable for irrigation. However, it is noted that the concentration of As (54.70 μg·L−1) in the sampling site of surface water (i.e., S3) exceeded the permitted level for the irrigation of vegetables and water crops in the dry season, thereby being no longer suitable for irrigation. Our results suggest that the high concentrations of metal compositions (e.g., Al, Pb, Mn, and As) should be controlled by some targeted measures to prevent further metal pollution in karst water of Nandong underground river basin. Our study also provides an integrated method for the comprehensive understanding of water quality in karst surface water and groundwater.

Since 2008, soil and water treatment and ecological restoration have been applied in the karst areas of Southwest China, but the effect of the treatments in karst fault basins is not clear. As a typical watershed of a faulted basin, studying the influence of landscape pattern changes on runoff and sediment yields in the Nandong underground river system (NURS) helps to establish the relationship between watershed and runoff and sediment changes. It provides a theoretical basis and effective method for water and soil management assessment, and soil and water treatment in karst fault basins. The vegetation topographic factor (VTF) was constructed using the normalized vegetation index (NDVI), digital elevation model (DEM) and water-system map from 2000 to 2018. On the basis of VTF classification, the vegetation topographic landscape index (VTLI) was calculated using the FRAGSTATS software, and the effects of VTLI changes on NURS runoff and sediment yield were analyzed. The study found the following: (1) PD, IJI, LSI and SHDI were positively correlated with runoff and sediment yield (p < 0.01), and the correlation coefficients were 0.693, 0.668, 0.551 and 0.582 and 0.62, 0.635, 0.627 and 0.63, respectively. AI and CONNECT were significantly negatively correlated with runoff and sediment yield (p < 0.01), and the correlation coefficients were −0.551 and −0.596, −0.627 and −0.446, respectively. The LPI and DIVISION index were not significantly correlated with discharge, but were significantly correlated with sediment yield (p < 0.05), and the correlation coefficients were −0.179 and 0.271, respectively. (2) The interpretation of VTLI for runoff increased from 0.639 to 0.778, and the interpretation of sediment transport decreased from 0.809 to 0.613. (3) In urban areas, VTF decreased and was persistent. VTF increased in the basin mountain edge area. In mountainous areas, VTF was unchanged, but has an antipersistence trend. The NURS ecological restoration project had achieved obvious results, and the change in the watershed increased runoff production and reduced sediment production. The capacity of soil and water conservation in the high slope area of the mountain edge of the basin recovered and showed a trend of sustainable development. Due to the urban expansion brought about by economic development, the capacity of soil and water conservation around the city has declined, and it showed a sustainable development trend. Policymakers should strengthen the ecological environment of urban areas and coordinate development within mountainous areas.

Serious soil and water loss affects the economy and the living quality of the population in faulted basins. Since 2002, China has carried out large-scale ecological restoration projects in karst areas. However, the karst faulted basins have experienced complex climatic changes, which makes it difficult to assess the ecological restoration effects quantitatively. Using the improved Budyko model, basin factor (n) and sediment content factor (C) were divided into climate influence and ecological restoration influence by second-order approximation, and the change ratio of climate influence and ecological restoration on sediment yield and loss was quantitatively calculated in the representative basin of the Nandong Underground River System (NURS). This was carried out in order to effectively distinguish the effects of climate change and ecological restoration on runoff and sediment change in the NURS. Furthermore, this study sought to understand the mechanism of runoff and sediment change and to evaluate the ecological restoration in the faulted basin to provide a scientific basis for the next stage of soil and water conservation policy formulation. The results showed that: (1) Using Pettitt to test the abrupt change of water and sediment in the NURS from 1987 to 2018, we found that 2002 was the abrupt change year of water and sediment in the basin. Before and after the mutation, the runoff and sediment yield decreased significantly, with the change rates of −15.5% and −51.8%, respectively. The decrease in precipitation and the increase in E0 were not significant, which were −4.5% and 1.4% respectively. (2) By calculating the correlation coefficient and the double logarithm function, it was found that the maximum temperature is the main climatic factor affecting the underlying surface factor n, and precipitation is the main climatic factor affecting the sediment concentration c. (3) Climate change reduced runoff by 77.6%. Ecological restoration has reduced sediment by 51.3 percent. The sensitivity of runoff to maximum temperature was 3.61. The sensitivity of grain yield to precipitation and NDVI was 5.37 and 3.26, respectively. The results show that climate is the main factor of runoff reduction, and ecological restoration is the main factor of sediment reduction. Ecological restoration has greatly reduced sediment production, and ecological engineering has made remarkable progress. However, the reduction of runoff caused by climate change should be paid more attention. The results of these studies will help to better formulate land use management policies for soil and water conservation.

In order to investigate the soil micro-plastic pollution in karst areas, this paper takes the karst depression of Longhe Village, Pingguo County, Guangxi Province as the research object, and sets up 15 sample collection points in farmland and forest areas. Through the collection, treatment and identification of soil and water samples, the quantity, size and material information of microplastics can be obtained. The results showed that:（1） Microplastic pollution was widespread in the study area. The average concentration of microplastic in farmland soil was（4.88 ± 0.35） pieces/g～（2.7 ± 0.35） pieces/g, and the average concentration of microplastic in forest soil was（8.12 ± 1.99） pieces/g ～（2.42 ± 0.31） pieces/g.（2） Affected by human activities, the pollution situation of the two basins in the east and west of the study area is different.（3） The farmland soil in the western basin is seriously polluted by microplastics due to agricultural activities. The forest soil in the eastern basin is affected by artificial grazing, and the content of microplastics in the soil is high.（4） The size of microplastics in the soil of farmland and forest areas is small, most of which are in the range of 20～100 μm, and account for 92% and 90.87% of the total particle number in their respective areas.

The chemical weathering of carbonate rocks is the main form of interaction between earth spheres in the karst critical zone. The karst weathering cover, which is composed by residua from carbonate rocks weathering, contains important information about the climate environment and material cycle. We present the chemical composition of weathering covers in karst area of Guilin, Guangxi province, analyze their weathering process and strength, and compare them with the other weathering covers in other karst area in China, including Yunnan, Guizhou, Hunan, and Qinghai Tibet Plateau. The results showed: (1) the chemical composition of Guilin weathering covers were similar to that of carbonate weathering covers in other areas of China, and had the common characteristics of uniform distribution of chemical composition in the profile and obvious enrichment of Fe, Al and trace elements. During the formation of carbonate weathering cover and the residua, the rapid dissolution of Ca and Mg had an important impact on the migration and enrichment of other elements. (2) The chemical index of alteration (CIA) of carbonate weathering covers in Guilin and other karst areas of China was much larger than that in the upper crust (UCC) (60.13), which showed strong chemical weathering characteristics of the humid and hot climate. (3) The weathering process of carbonate rock was different from that of silicate and loess. In the early stage of carbonate rock weathering, soluble components (calcite and dolomite) had been rapidly dissolved and leached. All the carbonate weathering residua was measured to be in the stage of K2O weathering and Al2O3 increasing. Therefore, the weathering degree of carbonate weathering cover was mainly determined by the leaching of K2O and the increase of Al2O3. As a result, there was no correlation between CIA and Na/K (molar ratio), but was a significant negative correlation between CIA and K/Al (molar ratio) in the carbonate weathering cover. (4) The CIA values of weathering residua and carbonate weathering cover in southern China were negatively correlated with latitude, reflecting the influence of climate factors. From the influence of lithology, the chemical compositions of parent rock can affect the CIA of weathering cover, and the content of insoluble matter in carbonate rock was negatively correlated with CIA. From the influence of topography, the CIA value of weathering residua decreased from the high to the low position and from the shallow to the deep part of the profile.

[研究目的]近年来,随着生活水平的不断提高,人们对健康饮水的要求也在不断提高,寻找与开发富含H2SiO3等矿物质优质地下水已成为关键.[研究方法]本文以昭觉地区水文地质调查工程、地下水污染调查工程所获取的地下水化学数据为基础,探讨了昭觉地区富H2SiO3地下水的分布特点、元素水文地球化学特征、形成条件及成因.[研究结果]结果显示:(1)全县富H2SiO3(≥25 mg/L)地下水均属于低矿化度偏碱性水,分布在基底岩石为玄武岩的6个片区,H2SiO3含量一般介于25.74～46.04 mg/L,pH含量一般介于7.4～8.58,TDS含量一般介于49.4～333 mg/L;(2)玄武岩地下水存在HCO3-Ca、HCO3-Ca·Mg、HCO3-Ca·Na、HCO3-Ca·Mg·Na、HCO3-Na等5种水化学类型,总体以HCO3-Ca·Mg为主,其次为HCO3-Ca,再次为HCO3-Ca·Na,三者分别占总采样点数的50.00％、25.76％、12.12％;(3)全县富H2SiO3地下水的形成受水岩相互作用、硅酸盐矿物的分布范围及其可溶性、围岩裂隙发育程度、水源涵养及补给条件等四方面因素影响,其中水岩相互作用占据主导作用;(4)在后续开发利用过程中,需进一步揭示影响地下水中H2SiO3分布与迁移的因素.[结论]研究结果可以为昭觉地区矿泉水产业的发展及城乡优质水源地的建设提供依据.

This study explores the possibility of deciphering changes in the total area of a karst wetland due to shifts inland use, economy and population over a long-term period (35 years) and microclimate changes (1958-2019). To achieve this goal, we focused on Huangcaozhou Karst Wetland, a national karst wetland park located in China. Based on remote sensing interpretation, long-term climate data, and statistical yearbook datasets, our results showed that from 1984 to 2019, owing to the rapid rates of urbanization and economic development, swamplands in our study area decreased by 16.4%, while urban lands increased up to 16.7%. The inflection point on the land use and land cover (LUCC) curve we constructed appeared in 2006, after which the areas of swampland, rocky desertification land, and wasteland sharply decreased and those of urban land and farmland increased. This is consistent with the increase in gross domestic production (GDP) and the totalnumber of inhabitants. From 1958, when Luxi registered an annual average temperature of 14.8 degrees C, to 2019, the air temperature increased with a gradient of 0.157 degrees C per decade, until it reached an average of 15.3 degrees C. We did not find a clear trend for the number of annual rainy days (average of 140.6 rainy days per year) but the mean torrentiality (average annual volume divided by the annual number of rainy days) shows a slight trend of increase (0.72 mm per day per decade). Precipitation we found has gradually declined. We concluded that economic and demographic changes are interacting with microclimate changes, which are affected by the regional eco-environment over a long-time scale in the Huangcaozhou Karst Wetland, causing the wetland quality significantly varied in recent decades. This would help to develop more efficient land management plans to better correctly handle new human activities allowing policymakers to regulate the wetland ecosystem in Southwestern China.

植被恢复是生态系统功能恢复的前提和基础,在生态系统恢复中具有重要的地位和作用.而恢复区域的自然植被分布规律是植被恢复树种选择的重要参考依据.本文通过遥感解译与现场调查相结合的方法,对抚仙湖流域的植被类型及分布进行了调研,分析了植被类型的特点、垂直类型分布特征以及植被类型与坡度、坡向的分布关系,并对流域地带性植被恢复和树种选择提出建议.

In karst areas, underground riverine sediment has been widely used to reflect the subterranean stream basin erosion, which influenced by both of precipitation and anthropogenic factors. In this study, 15-years of the sediment yield across Nandong underground river system of China were monitored, Mann-Kendal mutation test and simple proxy indicators were used for detecting the influences of human activities and precititation on sediment yield. The results showed that: 1) both of the anthropologic factor and rainfall impacted sediment yield, although the influence of anthropologic factor on sediment yield was greater (76.38%), and 2) rainfall showed a hysteresis effect on soil and water loss. There were three distinct stages based on the mutation points and variation characteristics of sediment yield from 1998 to 2014, resulting from different driving forces. Before 2004, the decease of sediment yield was caused by natural forest protection project in the whole basin. During 2004 to 2008, because of drought, flood disaster and cultivation on steeper slope, sediment yield of the basin increased. After 2009, sediment yield decreases due to the construction of soil conservation projects and mushrooming reservoirs. As human population is expected to increase, these findings are expected to provide insights for watershed management and ecological restoration in the fragile karst ecosystem.

The hydrogeochemical characteristics of groundwater are an important element in the study of the spatial and temporal variation of groundwater resources, which is crucial to water resources utilization, ecological environmental protection, and human development. Water samples were collected at eight observation of Nandong Karst Water System (NKWS) sites in each month of 2019, and the main ions and isotopes of the water samples were examined. The hydrogeochemistry characteristics of groundwater and its differences with surface water were explored by using the methods of multivariate statistics, Gibbs model. Results showed that the water chemistry types of groundwater were mainly HCO3–Ca and HCO3–Ca·Mg. The analysis of hydrogen and oxygen isotope showed that the initial recharge source of surface water and groundwater were atmospheric precipitation, and the measured hydrogen and oxygen isotopes of surface water were heavier due to the strong evaporation effect. The natural and anthropogenic processes contributed to the chemical composition of surface water and groundwater in the study area. However, the main factor affecting the quality of surface water and groundwater was the input of anthropogenic contaminants. In terms of natural factors, the main chemical ions of surface water and groundwater were mainly controlled by water-rock action originating from weathering and hydrolysis of rocks and soils. Ca2+, Mg2+, and HCO3− mainly originated from natural dissolution of carbonate rocks. K+, Na+, SO42−, and Cl− were partly from atmospheric precipitation. For human activities, Na+ and Cl− were partly from domestic water for local residents. SO42− in surface water mainly came from mining. NO3− in groundwater mainly came from chemical fertilizers, and NO3− in surface water were mainly from human waste and domestic sewage.

In karst environments, soil erosion is a prominent environmental issue that can cause many other problems. Researching the erosion and deposition rates at the hillslope scale in small watersheds is important for designing efficient soil and water conservation measures for the small watersheds even the large scale areas. In our research, the closed watershed, a representative depression in karst gabin basin, located in the Yunnan province, Southwest China, was selected to assess the soil erosion and sediment mobilisation at different hillslope positions using the 137Cs tracing technique. The results showed that the soil erosion rates in the shoulders, backslopes and footslopes were 0.87, 0.35 and 0.49 cm a-1, respectively, meanwhile the soil sediment rate in depression bottom was 2.68 cm a-1. The average annual soil erosion modulus of the complete hillslope was 632 t km-2a-1, which confirmed the serious gradation according to karst soil erosion standards. The sediment delivery ratio would summarize 0.82 in the whole catchment according to the square of hillslope and depression bottom. To identify which factor could play the most important role in influencing the estimations using 137Cs, a linear correlation and Principal Component Analysis were conducted. The results showed 137Cs concentration of different soil depth at different hillslope positions were significantly correlated with soil organic matter (SOM) and total nitrogen (TN) (P<0.05). As the typical karst geomorphological types, these findings are expected to provide data support for the whole watershed soil erosion management and ecological restoration in fragile karst ecosystem.

本文对滇东断陷盆地南洞岩溶地下水系统各地下河的水文动态特征进行了分析,推断了南洞岩溶地下水系统的结构特征.根据岩性构造、地下河发育以及补径排关系,将其划分为四个子系统.分别采用降雨入渗系数法和径流模数法对南洞岩溶地下水系统的天然资源量进行计算,计算结果分别为35610.7万m3/a和33460.2万m3/a.用枯季径流模数法对南洞岩溶地下水系统的可采资源量进行了计算,计算结果为23407.3万m3/a,其可开采资源量巨大.南洞地下河在没有天然补给量的情况下,120天消耗的调蓄量为4503.3万m3,南洞地下河日允许开采资源量为49.4万m3/d.二号暗河建库蓄水条件下库区上游的日允许开采量为75.9万m3/d,蓄水库容来源于工程设计,资源保证程度高.本次研究可为南洞岩溶地下水资源的开发利用和调配提供科学依据.

The concentrations of 10 metals (Cd, Cr, As, Al, Cu, Pb, Zn, Mn, Hg, and Fe) in 27 groundwater samples collected during different periods (wet, normal, and dry) in the Huixian Karst wetland, the largest subtropical low-altitude karst wetland in China, were detected and analyzed to investigate pollution and health risks. The pollution characteristics, distribution, and health risks of the metals in groundwater were revealed by a comprehensive pollution assessment, multivariate statistical analysis, and health risk assessment model, respectively. The results showed that the average concentrations of metals in groundwater were followed the order of Mn > Fe > Zn > Al > Hg > Cr > Cu > Cd > As > Pb. The maximum concentration of Mn (1022.00 μg·L-1) was found in the wet season, while that of Hg (42.40 μg·L-1) was found in the normal season, and both were over the corresponding standard limits. The results of the pollution assessment indicated that only Mn pollution reached level Ⅵ in the wet season, while Cd, Al, Zn, and Fe pollution were at the level of Ⅲ. Only the Hg pollution level reached level Ⅵ while Al pollution reached the level of Ⅲ in the normal water period. According to the above results, the water quality in the dry season was better than that in the wet and normal seasons in terms of the 10 metals. The concentrations of Zn, Cd, Mn, and Al in groundwater were affected by human activities, while the time-scale characteristics of these were not obvious. The concentrations of As, Fe, Cu, and Cr were all affected by human activities and the time-scale, while the concentrations of Hg and Pb were mainly manifested in time-scale characteristics. The results of the health risk assessment of the water due to drinking and the skin penetration pathway indicated that the total health risks followed the order of normal season > the wet season > the dry season. The carcinogenic risks caused by Cr for adults and children through drinking pathway in the wet season (8.03×10-5 a-1 and 8.76×10-5 a-1), normal season (1.15×10-4 a-1 and 1.26×10-4 a-1),and dry season (8.72×10-5 a-1 and 9.51×10-5 a-1) exceeded the maximum allowed level (5.0×10-5 a-1) in all periods. Hence, Cr was the main metal element that caused carcinogenic risks. For the sake of drinking water safety, the concentrations of Mn, Hg, and Cr in groundwater should be controlled before drinking.

云南泸西岩溶断陷盆地水资源丰富,但水资源时空分布极为不均,水资源利用率低.盆地地貌具有水平分区明显,垂向分级清楚的特点,盆底沉积平坝区是南盘江流域的局部上层排泄基准,其间残存和恢复重建的湿地具有调节和净化水的功能,且高程接近于供水需求区带.因此,分析和构建地表水-地下水联合调度的水资源循环利用方案,可有效提高水资源的利用率.通过研究泸西典型岩溶断陷盆地流域的地质环境条件与水循环系统,查明其水资源赋存状况、可开发资源量和开发利用现状,以地球系统科学为指导,应用系统分析、水文及水文地质分析评价等方法,结合黄草洲、平海子湿地生态的恢复重建和涵养,提出岩溶断陷盆地水资源的循环利用方案,一是黄草洲湿地生态的恢复重建和涵养,采用物理、生物、化学措施进行水处理净化,泵站提水供应生产、农业灌溉循环利用,形成生态恢复工程-资源循环利用的方案;二是工农隧道调蓄时空不均的内涝,引自平海子水库,旱季供灌溉、雨季供发电;有效提高岩溶断陷盆地水资源的循环利用水平.云南岩溶断陷盆地众多,可在盆地下游建湿地或净化池,处理生活污水和地表水,提水输送、隧道引水调蓄内涝、抗旱,解决时空不均的水资源利用.该方案可操作性强,在断陷盆地推广运用前景好.

在调查研究典型喀斯特断陷盆地水文地质特征、地表水文过程、"五水"转换及水资源均衡,研发地下水高效开发利用、地表水调蓄、水污染风险评估与水质修复、农田节水灌溉及土壤保墒、水资源优化调控等系列技术的基础上,以可持续发展和系统科学理论为指导,构建了喀斯特断陷盆地水资源高效开发利用模式,包括理论与技术支撑体系和开发利用工程体系两个层次.前者的基本构成及内涵为:水资源高效开发利用工作流程、理论依据及技术支撑,是模式的理论与技术内涵;后者为沿着盆地地表、地下水的形成、运动和转换过程,从上游山区到下游河谷区,逐级分区部署的水资源开发利用工程体系,工程布局做到因地制宜、科学合理,大、中、小、微型并举,集中供水与分散供水兼顾,同时系统推进水质修复、水循环利用、节约用水等措施,实现水资源的高效和可持续开发利用.

In karst environments, soil erosion is a prominent environmental issue that can cause many other problems. Researching the erosion and deposition rates at the hillslope scale in small watersheds is important for designing efficient soil and water conservation measures for the small watersheds even the large scale areas. In our research, the closed watershed, a representative depression in karst gabin basin, located in the Yunnan province, Southwest China, was selected to assess the soil erosion and sediment mobilisation at different hillslope positions using the 137Cs tracing technique. The results showed that the soil erosion rates in the shoulders, backslopes and footslopes were 0.87, 0.35 and 0.49 cm a-1, respectively, meanwhile the soil sediment rate in depression bottom was 2.68 cm a-1. The average annual soil erosion modulus of the complete hillslope was 632 t km-2a-1, which confirmed the serious gradation according to karst soil erosion standards. The sediment delivery ratio would summarize 0.82 in the whole catchment according to the square of hillslope and depression bottom. To identify which factor could play the most important role in influencing the estimations using 137Cs, a linear correlation and Principal Component Analysis were conducted. The results showed 137Cs concentration of different soil depth at different hillslope positions were significantly correlated with soil organic matter (SOM) and total nitrogen (TN) (P<0.05). As the typical karst geomorphological types, these findings are expected to provide data support for the whole watershed soil erosion management and ecological restoration in fragile karst ecosystem.

为揭示断陷盆地区高原面洼地不同坡位土壤的抗蚀性能,以高原面洼地不同坡位灌草地(上坡、中坡、下坡、坡底)不同土层(0–20 cm、20–40 cm)土壤为研究对象,通过对土壤抗蚀性16个指标的测定与分析,研究了不同坡位对土壤抗蚀性的影响.结果表明:在不同深度土层中,土壤水稳性大团聚体含量都呈现出上坡>下坡>坡底>中坡(P<0.05),且随着土层深度的增加含量减少;各坡位土壤抗蚀性,0–20 cm土层,上坡>下坡>坡底>中坡(P<0.05),20–40 cm土层,下坡>坡底>上坡>中坡(P<0.05),随着土层深度的增加,土壤抗蚀性逐渐降低;粘粒、有机碳、电导、PAD、MWD湿为评价喀斯特断陷盆地坡位土壤抗蚀性的最佳五指标.建议根据各坡位土壤抗蚀性的差异采取不同措施,减小水土漏失同时增强土壤的抗蚀能力,以改善当地生态环境.

为了揭示会仙典型岩溶湿地水体特征和变化趋势,总结当前微生物研究现状,进一步挖掘微生物与污染物相互作用关系,以2019年5月采集的会仙岩溶湿地水样数据和近3 a相关文献报道数据为依据,进行水化学特征和微生物群落结构分析与总结.水化学分析结果表明:会仙岩溶湿地水体近3a超标组分包括NO3-,NH4+,Al,Mn和Hg,地下水水质优于地表水,水质整体呈好转趋势.微生物分析结果表明:沉积物和土壤中微生物菌群门水平相近,Proteobacteria为优势菌门,属水平差异较大,共有的主要菌属包括H16,Desul-fatiglans,Anaeromyxobacter,Geobacter,Stenotrophomonas及可利用大分子含碳有机物的可培养菌Bacillus.从微生物多样性和Bacillus指示菌结果可知:沉积物和土壤具有一定有机污染风险,且秋季风险高于冬季;养殖、旅游和垦殖等人类活动对会仙湿地产生一定污染影响,同时也会降低微生物多样性、数量和活性.针对该岩溶湿地当前研究现状,建议引入多组学方法并兼顾岩溶湿地的整体性原则,以期为会仙岩溶湿地生态恢复和污染治理提供支撑.