Identifying the spatio-seasonal pattern of hydrochemical evolution and surface water-groundwater interaction in a large urban river basin, Northwest China.

There is insufficient understanding of the spatio-temporal evolution of surface water-groundwater quality and hydraulic connection under both natural and human influences in urban river basins. To this end, this paper investigated the spatio-seasonal pattern of hydrochemical evolution and surface water-groundwater interaction in a typical urban river basin (Dahei River basin) based on isotopic and hydrochemical data of 132 water samples collected during three seasons (normal, wet and dry seasons). From the normal season to the wet season, surface water in the Dahei River basin was dominated by the impacts of evaporation and groundwater discharge processes. During this period, the precipitation and agricultural activities (canal irrigation) were frequent. Thus, groundwater was affected by irrigation infiltration of surface water and precipitation from high-altitude areas. From the wet season to the dry season, precipitation decreased and irrigation methods changed (canal irrigation → well irrigation). In this case, groundwater discharge had a stronger impact on surface water, and shallow groundwater was recharged by deep groundwater through the well irrigation. Under this hydrological pattern, the hydrochemical characteristics of surface water were mainly influenced by evaporation, human activities (agricultural irrigation and sewage treatment) and groundwater discharge. In contrast, the hydrochemical characteristics of groundwater were main influenced by water-rock interactions (dissolution of evaporites and silicates, and cation exchange) and human activities. This study contributed to a better understanding of the hydrochemical and hydrological processes in urban river basins and provided a theoretical basis for the sustainable management of water resources.

Effects of coal mining and climate-environment factors on the evolution of a typical Eurasian grassland.

Coal mining can significantly impact vegetation evolution, yet the limited information on its patterns and driving factors hampers efforts to mitigate these effects and reclaim abandoned mines. This study aimed to 1) examine vegetation evolution in a semiarid steppe watershed in northeast China; and 2) characterize the driving factors behind this evolution. We analyzed the impact of twelve selected driving factors on fractional vegetation coverage (FVC) from 2000 to 2021 using a dimidiate pixel model, Sen's slope analysis, Mann-Kendall trend test, coefficient of variation analysis, and Geodetector model. At a significance level of α = 0.05, our findings revealed a south-to-north decline pattern in FVC, a significant decrease trend in proximity to coal mines, and a notable increase trend adjacent to river channels. Approximately 37% of the watershed exhibited low FVC, while the overall temporal trend across the watershed was deemed insignificant. Areas surrounding the mines experienced a substantial reduction in FVC due to coal mining activities, while FVC variations across the watershed were linked to precipitation, temperature, and soil type. FVC predictions improved notably when interactions between multiple two-way factors were considered. Each driving factors displayed an optimal range (e.g., precipitation = 63-71 mm) for maximizing FVC. Given the study watershed's status as a national energy base, understanding vegetation responses to coal mining and climate-environment changes is crucial for sustaining fragile terrestrial ecosystems and socioeconomic development. Achieving a long-time balance between coal extraction and ecological protection is essential. The study outcomes hold significant promise for advancing ecological conservation, vegetation restoration, and mitigation of environmental degradation in semiarid regions affected by extensive coal mining and climate fluctuations. These findings contribute to the strategic management of such areas, promoting sustainable practices amidst evolving environmental challenges.

[Hydrochemical Characteristics and Control Factors of Groundwater in the Northwest Salt Lake Basin].

Taking the Tugeligaole sub-basin of the Jilantai Salt Lake Basin in Inner Mongolia as the typical study area, the groundwater samples of 22 points were collected, and their main characteristic indexes were tested during the wet season and the dry season separately in 2021. Mathematical statistics, Piper triangular diagrams, a Gibbs plot, ionic relations, and factor analysis were used to analyze and discuss the hydrochemical characteristics and formation mechanism of groundwater in different periods. Based on the evaluation of the groundwater quality using the water quality index(WQI) method, the potential risks of groundwater Cr6+ and F- were evaluated using the health risk evaluation model. The results showed that the groundwater was overall weakly alkaline; the dominant anions and cations during the different periods were Cl- and Na+, and the water chemistry type was mainly Cl--Na+; the groundwater quality was generally good, and the difference in water quality between the wet season and the dry season was not significant; adults and children had higher carcinogenic health risks in the dry season than that in the wet season, and the health risks of children were significantly higher than those in adults. The maximum carcinogenic health risk of drinking water exposure to Cr6+ in adults and children was higher than the maximum acceptable risk level(5×10-5). The chemical evolution of groundwater was mainly affected by evaporative concentration, evaporative salt rock dissolution, and cation exchange, and the main control factors were evaporative concentration(contribution rate of 54.19%), native geological environment factors(contribution rate of 12.99%), and carbonate rock dissolution(contribution rate of 11.66%). The study results have significance to some degree to the sustainable exploitation and utilization of groundwater resources and environmental protection of the salt lake basin.

[Hydrogen and Oxygen Isotopic Characteristics and Influencing Factors of "Three Waters" in Shandian River Basin].

In this study, we collected precipitation from February 2020 to February 2022 and the surface water and groundwater in the wet (August) and dry (October) periods of 2021 in the Shandian River Basin. Stable isotope technology was used to analyze the temporal and spatial changes in the hydrogen and oxygen stable isotopes of the "three waters" in the basin to explore the relationship between water isomorphs and environmental factors and to reveal the water conversion relationship using the end element mixing model. The results showed that the slope and intercept of the local precipitation line were smaller than the local atmospheric precipitation line. The water vapor mainly came from westerly water vapor, polar air mass, and East Asian monsoon circulation. The precipitation isotope had a significant temperature effect. In terms of time, the isotopes of surface water and groundwater were more enriched in the dry season than those in the wet season, and the d-excess values of surface water and groundwater were lower than the global average, indicating strong local evaporation. Spatially, the δ18O value of the rivers had the same change characteristics in the wet and dry seasons, showing gradual enrichment from the upstream to the downstream, and the groundwater δ18O high value area was unevenly distributed in space, with groundwater δ18O values becoming more depleted with the increase in burial depth. The highest slope of the groundwater water line was 7.87 in the wet season, which was very close to the slope of the local atmospheric precipitation line and river water line, indicating that there was a complex hydraulic connection between the "three waters" in the wet season. The surface water in the study area was mainly supplied by precipitation during the wet season and then by groundwater runoff. These results can provide a theoretical basis for revealing the hydrological cycle in arid and semi-arid areas.

[Water use characteristics of artificial sand-fixing vegetation on the southern edge of Hunshandake Sandy Land, Inner Mongolia, China]. / æµ‘å–„è¾¾å ‹æ²™åœ°å—ç¼˜äººå·¥å›ºæ²™æ¤è¢«æ°´åˆ†åˆ©ç”¨ç‰¹å¾.

We examined the characteristics of water use in typical tree species of arbor and shrub in Hunshandake Sandy Land, Populus cathayana and Salix gordejevii, in the different seasons, with the aim to provide theoretical basis for the structural optimization of the artificial shelterbelt. Samples of precipitation, soil water, groundwater and stem water of the two vegetation were collected, and their distribution characteristics of δD-δ18O were analyzed by hydrogen and oxygen stable isotope technology. The contribution rate of these potential water source to the arbor and shrub species were calculated using multi-source linear mixing model. The precipitation equation line in the study area was δD=7.84δ18O+9.12, while soil moisture lines in the dry and wet season were δD=3.56δ18O-41.28 and δD=4.30δ18O-42.02, respectively. The δD-δ18O of soil water and stem water in the two seasons were lower than the precipitation δD-δ18O, indicating that both of them were strongly affected by the evaporation. Soil water contents in the shallow layer were strongly affected by rainfall and evaporation, with substantial fluctuation. With the increases of soil depth, soil water content tended to be stable, and the hydrogen and oxygen isotope in each soil layer showed significant differences. In the dry season, P. cathayana mainly utilized soil water in 0-40 cm and 120-200 cm layers, with contribution rates of 50.2% and 31.5%, respectively. S. gordejevii mainly absorbed soil water in 20-40 cm and 60-100 cm layers, and the contribution rates were 53.2% and 22.9%, respectively. In the wet season, the greatest contribution of soil water to P. cathayana was mainly in the 0-40 cm soil layer, accounting for 72.8%. S. gordejevii was mainly in the 0-20 cm soil water, evenly utilized the deeper soil water and groundwater. Due to the differences in root depth and distribution of the arbor and shrub, their water use strategies differed in different seasons, which was conducive to the stability of the shelterbelt community and tree species coexistence in Hunshandake Sandy Land. We proposed that the mixed planting species with different root depth should be considered in the future planting of artificial shelterbelt, which would help rationally utilize water resources and maintain the stability of sandy land ecosystem.

Responses of soil moisture to climate variability and livestock grazing in a semiarid Eurasian steppe.

Soil water is vital for sustaining semiarid ecosystems. However, data on soil moisture have unlikely been continuously collected for a long time (e.g., >50 years), let alone under various combinations of climates and livestock grazing intensities. The objective of this study was to formulate and parameterize an ecohydrological model for predicting long-term variability of soil moisture, taking a typical Eurasian grassland located in northeast China as the testbed. The parameters were determined by extensive literature review, field reconnaissance, laboratory analyses of soil and grass samples, and model calibration using daily soil temperatures and soil moistures measured at four depths from 2014 to 2017. The model, driven by the daily climate data from 1955 to 2017, performed well in reproducing the measurements. Across the assessment years of 1960 to 2017, the daily soil moistures were predicted to vary from 0.02 to 0.38. Overall, the soil moistures at a shallower depth were smaller but had a wider range than those at a deeper depth, with a largest mean and a widest range around the 30 cm depth. Regardless of the depths, the soil moistures pulsed in beginning March and plateaued from May to September. Livestock grazing was precited to reduce top 1.5-cm soil moistures but increase moistures of the beneath soils. The optimal grazing intensity was determined to be around 3.0 cattle ha-1, above which wind erosion would become a concern. The grazing impacts on soil moisture were found to monophonically decrease with increase of evapotranspiration or annual precipitation of larger than 220 mm. For the years with an annual precipitation of less than 220 mm, such grazing impacts either increased or decreased with increase of precipitation, depending on the relative magnitude of evapotranspiration. Climate change will diminish soil moisture pulses in early spring, likely intensifying soil erosion by wind.

Characteristics and environmental driving factors of water transformation in the Balaguer River watershed of Inner Mongolia steppe.

Inner Mongolian steppe is one of the ecological barriers in China. The variation of water resources is very important for the development of social-economy and the protection of eco-environment. We collected 254 water samples of precipitation, river, and shadow groundwater during wet-season and dry-season of 2018-2019 from Balaguer River watershed and meansured the physical-chemical indicators, δD and δ18O of water samples. The stable isotope technology, mathematical statistics, and the inverse distance weighting method were used to analyze the stable isotope composition, spatial-temporal variation, and impact factors. Moreover, the d-excess and the isotopic mixing ratio formula were used to analyze the conversion characteristics of different water and to identify their environment driving variables. The results showed that δD and δ18O of precipitation, river and shallow groundwater were higher in wet season than in dry season. The driving factors of different water transformation in the watershed were air temperature, altitude, and groundwater depth. Altitude was significantly negatively correlated with river δD, and the δD and δ18O of groundwater. δD and δ18O of groundwater fluctuated significantly in the area with groundwater depth less than 10 m, but were stable in other areas. There was a positive correlation between precipitation δ18O and air temperature. The d-excess in wet season was higher than that in dry season, with a decreasing distribution characteristic from southern to northern part in the study area. More than 50% river in upper stream came from precipitation, while more than half river water converted to groundwater, with different recharge-drainage relationships existed between surface water and groundwater in different river reaches.

[Impact of diabetes mellitus on clinicopathological factors and prognosis of patients with colorectal cancer.].

OBJECTIVE: To analyze the impact of diabetes mellitus on the clinicopathological factors and prognosis of patients with colorectal cancer. METHODS: A total of 599 patients with colorectal cancer treated between January 2000 and June 2007 were collected retrospectively. The patients were divided into diabetes mellitus (DM) group and non-diabetes mellitus (NDM) group. The pathologic factors data was compared between the two groups, and the Logistic multivariable analysis was performed. The Cox regression model analysis of prognosis data was applied in 402 patients who underwent radical surgery without preoperative neoadjuvant therapy. RESULTS: A total of 58 cases (9.7%) developed diabetes mellitus. Significant differences was found in the body-weight, age, hypertension between the two groups (P < 0.05), while no significant differences in the pathologic factors, such as tumor differentiation, invasion depth, lymph node involvement, TNM stage and lymphovascular invasion was found between the two groups (P > 0.05). There was no significant correlation between diabetes mellitus and the pathologic factors on the Logistic analysis (P > 0.05). Among the patients underwent radical surgery directly, neither disease progression curve (P = 0.521) nor overall survival curve (P = 0.909) presented significant differences between the two groups. It's not shown that diabetes mellitus was significantly associated with the prognosis of patients with colorectal cancer by using Cox regression analysis (P = 0.991). CONCLUSIONS: Diabetes mellitus does not significantly influence the clinicopathological factors and the prognosis of colorectal cancer in patients receiving radical surgery, and it requires more investigation.

[Comparison of two-year efficacy between procedure for prolapse and hemorrhoids and Milligan-Morgan hemorrhoidectomy in treatment of III and IV degree internal hemorrhoids].

OBJECTIVE: To compare the long-term efficacy of procedure for prolapse and hemorrhoids (PPH) and Milligan-Morgan hemorrhoidectomy (MMH) in the treatment of III and IV degree internal hemorrhoids. METHODS: One hundred patients were randomly divided into two groups and received PPH (n=42) and MMH (n=58) respectively. After two years, the efficacy, complications and function of defecation were compared. RESULTS: Two years after operation, the morbidities of hydrorrhea (2.38% vs 20.69%, P=0.007), dermal neoplasm formation (9.52% vs 25.86%, P=0.040) and narrowing in the caliber of the stools (2.38% vs 18.97%, P=0.027) were significantly lower in PPH group than those in MMH group (P<0.05). The morbidities of overall complication (9.52% vs 25.86%, P=0.040) and overall abnormal function of defecation (9.52% vs 29.31%, P=0.017) were lower in PPH group than those in MMH group (P<0.05). However, there were no significant differences of the morbidity of relapse (14.29% vs 10.34%, P=0.549), patient satisfactory degree (92.86% vs 87.93%, P=0.636) and overall symptom recurrence rate (19.05% vs 25.86%, P=0.424) between the two groups. CONCLUSIONS: Long-term efficacies of procedure for prolapse and hemorrhoids and Milligan-Morgan haemorrhoidectomy in the treatment of III and IV degree internal hemorrhoids are similar. PPH has better safety, less complications and less effect on abnormal function of defecation compared with MMH.

[Relationships between row crop evapotranspiration and two sources- energy partition and exchange under non-water stress condition].

With the maize harvested for green fodder and grown at the Hunshandake sand area as test row crop,and by combining two sources- energy balance model with dual crop coefficient approach presented in FAO-56,this paper estimated the available energy partitioned into two sources, canopy and soil surface (Ac and As), and the latent and sensible heat fluxes, lambdaEc, lambdaEs, Hc and Hs. The results showed that under non-water stress condition, the interaction between Hc and lambdaEc made canopy absorbed a micro-advection to enhance transpiration expressed by latent heat flux,with the value of (lambdaE(i)c-A(i)c). The greatest enhancement of transpiration occurred at the crop development stage with leaf area index between 0.6 and 2.4, and the average of the enhancement was 4.32 MJ x m(-2) x d(-1). Soil evaporation was in progress with a rate below the available energy of soil, due to the interaction between Hc and lambdaEc under non-water stress condition, except a few days immediately after heavy rain. The evaporation rate depended on the percentage of soil available energy dissipated as latent heat flux. The average value of minimum percentage, 11.5%, occurred at mid-season stage,while that of maximum percentages,51.9%, occurred at initial stage. Latent heat fluxes were the important components of energy exchange during the process of evapotranspiration. The available energy dissipated as latent heat fluxes of the two sources during crop development, mid-season, and late season stages accounted for over 83% of the total energy.