Comprehensive evaluation of hydrological drought and the effects of large reservoir on drought resistance in the Hun River basin, NE China

Evolution of drought under changing climate and the operation of large reservoir play an important role in drought warning and control. Thus, the evolution characteristics of hydrological drought and the effects of large reservoir on drought resistance are explored in the Hun river basin (HRB). Firstly, Standardized runoff Index (SRI) was adopted to evaluate the evolution characteristics of hydrological drought. Meanwhile, based on drought duration and severity identified by the run theory, the copula function with the highest goodness of fit was selected to calculate the return period of hydrological drought. Furthermore, the propagation time from meteorological to hydrological drought were determined by calculating the Pearson correlation coefficients between 1-month SRI and multi-time scale Standardized precipitation index (SPI). Finally, based on the cumulative precipitation deficit thresholds for triggering hydrological drought, the impact of large reservoir on drought resistance of the basin was revealed. The results show that: (1) hydrological drought showed a slight strengthening trend in the eastern, while presented alternate characteristics of drought and flood in the western and center of the HRB from 1967 to 2019; (2) the western and center of the HRB were vulnerable districts to hydrological drought with longer drought duration and higher severity; (3) the most severe drought with drought duration of 23 months, severity of 28.7, and corresponding return periods that both exceed the thresholds of duration and severity and exceed the threshold of duration or severity were 371 years and 89 years, respectively; (4) the propagation time from meteorological to hydrological drought of the lower reaches of large reservoir has been significantly prolonged owing to the operation of large reservoir; and (5) the operation of large reservoir strengthened the drought resistance in the lower reaches while lightly weaken in the upper reaches of large reservoir.

Pollution and Ecological Risk Evaluation of Heavy Metals in the Soil and Sediment around the HTM Tailings Pond, Northeastern China

Tailings ponds are a main heavy metal pollution source in mining areas. In this study, the geo-accumulation index (Igeo) and the potential ecological risk index (RI) are used to evaluate the environmental impact of Hongtou Mountain (HTM) tailings pond on the surrounding area. Farmland soil, surface water, and sediment samples in the Hun River around the HTM tailings pond were collected. Heavy metal contents in the samples were analyzed by Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Results show that Cu, Zn, and Cd content in the farmland soil and sediment around the lower reaches of the Hun River (HTM tailings pond section) are obviously higher than the upper reaches. The Igeo values show that the farmland soil near the outlet of the tailings pond is the most polluted area. Cu was classified as moderate–strongly pollution, Zn was moderately pollution, and Cd was strongly pollution. Cd is the major pollutant in farmland soil, the monomial ecological risk (Eri) for Cd is a very high potential ecological risk. The potential ecological risk of sediment in the dry season is more serious than in the raining season. In the dry season, the Igeo index shows strong pollution for Cu and Cd at the confluence of the Hun River and the tributary from the HTM tailings pond, and a moderate–strongly pollution for Zn. Whereas, the Eri index shows that the monomial ecological risk for Zn at H3 is low, and Cu is moderate. The potential ecological risk at H3 is high, and Cd is the main source of the ecological risk around the HTM tailings pond.

A Framework for Ecological Compensation Assessment: A Case Study in the Upper Hun River Basin, Northeast China

With the rapid socio-economic development, human disturbances are believed to have resulted in the degradation of the watershed ecosystem. The ecological damage to and environmental pollution of river basins have caused great losses. It is widely agreed upon that the protection and restoration of river ecosystems should be on the agenda. Ecological compensation, an important tool to prevent the deterioration of water environments and achieve sustainable watershed development, has attracted increasing interest as a research subject. In this study, the upper reach of Hun River basin was selected as a typical study area. The primary purpose was to determine the allocation costs of ecological compensation in different regions for the river basin. The amount of willingness-to-pay (WTP) for the eco-compensation was estimated at 3.2 million dollars by the Contingent Valuation Method (CVM). Based on linear programming techniques, a Data Envelopment Analysis (DEA) created a primary value of the allocation costs. Considering the different weights of each region, a modified coefficient was introduced to correct the primary result on the basis of a questionnaire survey of river ecological protection and construction.

Funerary and Social Aspects of Koguryo Pottery

Purpose. Previous studies on Koguryo ceramics covered some general information on the archaeological objects found or specific related issues. Our research focuses on the ceramics found only in burials as we aimed at describing typological and technological features of the burial ceramics. The territorial and chronological comparative analysis of the vessels which has been conducted shows the features of each period and region in Koguryo and reveals the development of social background in this state. Results. The burial ceramics analyzed consists of 183 vessels which are divided into 22 types. According to the concentration of burials with ceramics, we identified 4 big areas along major river basins, which are administratively related to modern Liaoning and Jilin provinces of China, North and South Korea. Analysis of the spatial factor of burial ceramics shows that the largest variety of types was found in the Yalu River region, with the next Pyongyang area. This was due to the central location of these territories in Koguryo, which used to be the capital of the state for several centuries. By contrast, there are only few types and samples of funerary ceramics found in the Hun River and Imjin River basin. Most likely, it is due to the fact that they were provinces or suburbs with a political and economic system that was not considered safe yet. Our research shows territorial preferences in using certain types of burial pottery, which was classified according to its characteristics and features. Conclusion. Koguryo’s burial ceramics is divided into storage vessels and cooking vessels, and together they symbolically generalize the concept of “food.” We concluded that the concept of food in the Otherworld was important for the ancient Korean population. We also confirmed that after the 4th AD ceramic replicas of household items and glazed ceramics began to be buried in Koguryo tombs. It was closely related to the introduction of a new burial type in Koguryo.

Sources Identification of Nitrogen Using Major Ions and Isotopic Tracers in Shenyang, China

Stable isotopes are natural tracers that can provide quantitative information about the surface water/groundwater interactions and sources of pollutants in water. In this study, we measured δ18Owater and δ2Hwater and δ18Onitrate and δ15Nnitrate of the samples from the Hun River and groundwater in Shenyang City, China, where the water from the Hun River has a strong discharge and recharge connection with the groundwater. δ18Owater and δ2Hwater were used to determine the amount of surface water that was discharged into groundwater, while δ18Onitrate and δ15Nnitrate were employed to determine the sources of nitrate and ammonium in groundwater, which are the main contaminants in the study area. The reducing environment in groundwater may result from the prevailing iron and manganese, occurring from weathering of minerals and rocks, which prevents the ammonium being oxidized into nitrate. Results show that the amount of recharge from the Hun River into groundwater accounts for around 55.56–86.60% of the total groundwater in the dry season, and the ratio changed to 30.97–63.79% in the wet season. Multiproxy analysis (stable isotope analyses in combination with chemical and hydrogeological data of the study area) indicates that human activities, such as manure and sewage discharge, are the prevailing source of nitrogen in the waters.