Effects of neutral salt and alkali on ion distributions in the roots,shoots,and leaves of two alfalfa cultivars with differing degrees of salt tolerance

The effects of neutral salt and alkali on the ion distribution were investigated in two alfalfa （Medicago sativa L.） cultivars, including Zhongmu 1, a high salt-tolerant cultivar, and Algonquin, a low salt-tolerant cultivar. The alkali stress expressed more serious growth inhibition than the neutral salt stress at the same Na＋ concentration. Compared with Algonquin, Zhongmu 1 did not exhibit a higher alkali tolerance under the Na2CO3-NaHCO3 treatment with the low Na＋ concentration （50 mmol L-l）. The alkali increased the accumulation of Na＋, Ca2＋, and Mg2＋ in the root and changed the Ca2＋ and Mg2＋ balance in the entire alfalfa plant. The salt and alkali stresses decreased the K＋ and Fe3＋ contents of the roots and leaves, the root Mn2＋ content, and the shoot Zn2＋ content, but they increased the Fe3＋ accumulation of the shoots, the shoot and leaf Cu2＋ contents, and the leaf Zn2＋ content in both alfalfa cultivars. Based on the results obtained under the conditions of this experiment, we found that the salt and alkali stresses reduced the plant growth in both alfalfa cultivars, while the alkali caused a stronger stress than the neutral salt in alfalfa. Thus, we conclude that under hydroponic conditions, the deleterious effects of the alkali on plants are due to the distribution change of some trophic ion balance in the roots, shoots, and leaves of the plants by causing of Na＋, CO3^2-, and/or HCO3- stresses.

Root distribution and influencing factors of dry-sowing and wet-growing cotton plants under different water conditions

To study the effect of soil water and salt environment factors on the root growth of cotton under different moisture control,three different emergence water volumes(60,105,and 150 m^(3)/hm^(2)),two different frequencies(high frequency and low frequency)and one double film cover winter irrigation control treatment(CK:2250 m^(3)/hm^(2))were set up to analyze the spatial distribution patterns of soil water and salt environment and root density in dry sown and wet emerged cotton fields under diffe-rent moisture control conditions.The results show that the soil water content and water infiltration range gradually become larger with the increase of seedling water quantity,and the larger the seedling water quantity,the higher the soil water content.With the same seedling water quantity,the soil water content of the high-frequency(HF)treatment becomes obviously larger.The soil conductivity of each treatment tends to decrease gradually with the increase of seedling water and drip frequency,among which the distribution of soil conductivity of S6 treatment is closest to that of CK.With the increase in soil depth,the soil conductivity tends to increase first and then decrease.Compared with the low-frequency(LF)treatment,the high-frequency treatment shows a significantly deeper soil salt accumulation layer.The root length density(RLD)of cotton gradually increases with the amount of seedling water and the frequency of dripping.The soil layer of root distribution gradually deepens with the amount of seedling water in the vertical direction,and the RLD value in the horizontal direction is significantly greater in the mulched area than that in the bare area between films.This research can serve as a solid scientific foundation for the use of dry sowing and wet emergence techniques in cotton fields in southern Xinjiang.

Experimental Research on Salt-out Particle Motion and Concentration Distribution in a Vortex Pump Volute

The vortex pump is suitable for salt solution transportation. But the salt-out flow mechanism in the pump has not been understood fully. Salt-out layer formation and growth rate are closely related to crystal particle motion and concentration distribution. Study on the particle hydrodynamic characteristics in the pump volute becomes a key problem, because the crystal particles are mainly distributing in this zone after they enter the pump. Phase Doppler particle analyzer（PDPA） is used to measure the two-phase flow field in a model pump volute to get more understanding about the salt-out phenomenon. The crystal particle velocities are obtained in all three peripheral, radial and axial directions. Particle size and particle number density（PND） measurements are also performed in the experiment. Results are presented and discussed along the radial direction under different pump operating conditions, as well as various axial measurement positions. It is found that particle velocity gradient of peripheral component varies with the pump discharge. There is a turning point of relation between peripheral velocity component and discharge. Radial flow velocity curves look like a saddle shape and velocity magnitudes are changing greatly with the discharge. The non-equilibrium velocity feature between liquid and solid phase on this direction is also remarkable. Particles flow into the impeller at radial position R〈I, and the axial velocity component increases in this region. The particle size curve shows an open-up parabola distribution. The largest particles are distributing near the casing peripheral wall. As flow rate increases, accordingly PND increases. It also grows up in the axial-outward direction towards the suction cover. Crystal particle aggregation phenomenon can be revealed from the analysis of particle size and PND distribution, and the aggregation region is determined as well. Research results are helpful for optimal design of this kind of pump preventing salt-out.

Research on the Distributional Features of and Interrelationships Between the Dissolved Oxygen, Salinity, pH Value and Nutrient Salts in the Honghai Bay Waters

In this paper, the environmental factors are surveyed of the mariculture waters of the Honghai Bay from the late spring to the early summer (June) in 1998. The distributional features and variation laws of dissolved oxygen, salinity, pH value and nutrient salts in the sea water are expounded. Also discussed are their relationships between each other. The results show that the contents of dissolved oxygen and pH value in the sea water increase with the increasing temperature from north (except for No.15~17 stations) to south (expect for No.6 station). At the same time it is affirmed that photosynthesis is the major cause of the high contents of dissolved oxygen and pH value. And the nutrient salt shows a negative correlation with salinity. The total content of phytoplankton obviously increased with the reduction of nutrient salts from north to south.

DISTRIBUTION FEATURES OF GIANT SEA－SALT NUCLEI IN ATMOSPHERE OVER YONGXING ISLAND， XISHA ISLANDS，DURING NORTHEAST WINTER MONSOON

In this paper, the chlorine ions nuclei data, observed at Yongxing (Xisha Islands ) during November 1987, are analyzed. The main results are: 1) The average concentration of chiorine ions nuclei with dry diameters larger than 2 μm is 878 per litre and the average salt content is 105. 4μg/m3, in which special giant nuclei with dry diameters larger than 4 μm are 19O per litre. The largest dry diameter of chloride ions observed reaches 57 μm, which are larger than that observed there during the southwest summer monsoon. The spetrum type shows quasi-unimodal and exponential lapse. 2) The salt content decreases with the height over sea surface. 3) The concentrations of chlorine ions nuclei reach the maximum value at 0800 (Local time, same below ). and minimum at 0200.

Effects of Salt Stress on Growth and Ion Distribution in Seedlings of Asparagus officinalis L.

An Asparagus officinalis L. cultivar NJ978 was used to study the growing rate, salt ion content and mineral ion uptake and distribution in plants under salt stress. The results showed that salt stress significantly inhibited seedling growth and there was a negative relationship between seedling growth and salt concentration. The seedlings growth showed no significant decrease under low salt stress （NaCl≤50 mmol/L）, while high concentrations of NaCl led to detrimental effects on the growth of A. officinalis L.. With the increase of NaCl concentration, the Na ＋ content increased gradually in A. officinalis L. roots, stems and leaves while the K^＋ and Ca^2＋ contents had slow decreases. Under low salt stress, the seedlings of A. officinalis L. could prevent Na ＋ from transporting to aerial part by withholding Na ＋ in root, which could keep the balance of ions in aerial part, but under high salt stress （NaCl 〉 100 mmol/L）, the aerial part of seedlings accumulated superabundance of Na ＋, which limited the uptake of K^＋ and Ca^2＋ , so seedlings were damaged heavily, which manifested as the gradual decrease of K^＋/Na ＋ and Ca^2＋ /Na ＋ in the roots and aerial part of the seedlings. The selective absorption of K^＋, Ca^2＋ and Na ＋ （AS K,Na and AS Ca,Na ） was significantly increased with increased salinity, while the selective transportation （TS K,Na and TS Ca,Na ） increased at first and then decreased with the increased salinity. Therefore, the strong ability of salt exclusion and the regionalized distribution of ions in roots, stems and leaves could be one of the salt tolerance mechanisms of A. officinalis L.

Spatial Distribution of Soil Salinization Based on GIS in Tianjin Binhai New Area

The distribution of soil salinization was investigated based on GIS and field sampling in Tianjin Binhai New Area. The results showed that the average soil total salt content was 0.818%, with an average pH of 8.43, and the average CI and Na＋ contents were 0.27% and 0.22%, respectively. Presenting zonal distribution feature, the soil total salt content increased gradually from west to east of Binhai New Area. Statistics on the distribution areas of different salinization degrees showed that the area of non-salinzed soils only accounted for 3.18% of the total area; with an area of 107.43 km2, mild saline soil accounted for 6.34% of the total area; the area of moderate saline soil was 173.51 km2, accounting for 10.24%; and the area of sal- inzed soils was 217.36 km2, accounting for 12.82% of the total soil area. The area of saline soils （total salt content 〉0.6%） was 1 142.8 km2, accounting 67.42% of the total land area in Binhai New Area. And the areas for the soils with total salt content of 0.6%-1.0%, 1.0%-1.5%, 〉1.5% were respectively 388.47, 411.82, 342.51 km2, accounting for 22.92%, 24.3%, 20.21% of the total area.

Spatial distribution of soil moisture,salinity and organic matter in Manas River watershed,Xinjiang,China

With the classical statistical and geostatistical methods, the study of the spatial distribution and its in- fluence factors of soil water, salinity and organic matter was carried out for 0-70 cm soil layers in Manas River watershed. The results showed that the soil moisture data from all soil layers exhibited a normal distribution, with average values of 14.08%-21.55%. Geostatistical analysis revealed that the content of soil moisture had a moder- ate spatial autocorrelation with the ratios of nugget/sill ranging from 0.500 to 0.718, which implies that the spatial pattern of soil moisture is influenced by the combined effects of structural factors and random factors. Remarkable spatial distributions with stripped and mottled features were found for soil moisture in all different soil layers. The landform and crop planting had a relatively big influence on the spatial distribution of soil moisture; total soil salinity was high in east but low in west, and non-salinized soil and lightly salinized soil appeared at the northwest and southwest of the study area. Under the effect of reservoir leakage, the heavily salinized soils are widely distributed in the middle of the study area. The areas of the non-salinized and lightly salinized soils decreased gradually with soil depth increment, which is contrary to the case for saline soils that reached a maximum of 245.67 km2 at the layer of 50-70 cm. The types of soil salinization in Manas River watershed were classified into four classes： the sulfate, chloride-sulfate, sulfate-chloride and chloride. The sulfate salinized soil is most widely distributed in the surface layer. The areas of chloride-sulfate, sulfate-chloride, and chloride salinized soils increased gradually along with the increment of soil depth; the variation range of the average values of soil organic matter content was be- tween 7.48%-11.33%. The ratios of nugget/sill reduced gradually from 0.698 to 0.299 with soil depth increment, which shows that the content of soil organic matter has a moderate spatial autocorrelation. The soil organic matter in all soil layers met normal distribution after logarithmic transformation. The spatial distribution patterns of soil or- ganic matter and soil moisture were similar; the areas with high organic matter contents were mainly distributed in the south of the study area, with the lowest contents in the middle.

Porosity Distribution Characteristics and Geological Analysis of Brine Storage Medium in the Qaidam Basin, Western China

Underground brine is an unusual water resource that contains abundant mineral resources. It is distributed widely in the Qaidam Basin, western China, a hyperarid inland basin located in the northern Tibetan Plateau. Pores in the brine storage medium act as storage space and transmission channels of underground brine. Therefore, the porosity of brine storage medium determines its ability to store brine. In this study, Mahai Salt Lake was used as the research area as a modern saline lake located in the north area of the Qaidam Basin. A total of 100 porosity samples were collected from eight sampling points in two profiles of the research area at sampling depths of 1.30–314.78 m. The porosity distribution characteristics and influencing factors in brine storage medium were analysed according to the measured porosity data. Based on analysis of the pore structure characteristics, the brine storage medium contains intercrystalline pores, unlike conventional freshwater storage mediums. Moreover, the primary salt rock is susceptible to dissolution by lighter brine, facilitating the formation of secondary porosity. Due to the formation of secondary pores, a porosity greater than 20% remains even at buried depths greater than 100 m. Based on the geological statistical analysis, due to the geographic location, salt formation time, and depositional environment, the porosity values of Mahai Salt Lake do not exhibit a wider distribution, but also show more extreme values than a nearby salt lake. Based on the porosity characteristics by depth, due to the presence of secondary pores, flooding, stratigraphic static pressure, and other factors, porosity shows fluctuations with increasing depth.

Effect of Lithium Chloride on the Fibre Length Distribution, Processing Temperature and the Rheological Properties of High-Yield-Pulp-Fibre-Reinforced Modified Bio-Based Polyamide 11 Composite

The aim of this work was to investigate the effect of lithium chloride (LiCl) on the fibre length distribution, melting temperature and the rheological characteristics of high yield pulp fibre reinforced polyamide biocomposite. The inorganic salt lithium chloride (LiCl) was used to decrease the melting and processing temperature of bio-based polyamide 11. The extrusion method and Brabender mixer approaches were used to carry out the compounding process. The densities and fibre content were found to be increased after processing using both compounding methods. The HYP fibre length distribution analysis realized using the FQA equipment showed an important fibre-length reduction after processing by both techniques. The rheological properties of HYP-reinforced net and modified bio-based polyamide 11 “PA11” (HYP/PA11) composite were investigated using a capillary rheometer. The rheological tests were performed in function of the shear rate for different temperature conditions. The low-temperature process compounding had higher shear viscosity;this was because during the process the temperature was low and the mixing and melting were induced by the high shear rate created during compounding process. Experimental test results using the extrusion process showed a steep decrease in shear viscosity with increasing shear rate, and this melt-flow characteristic corresponds to shear-thinning behavior in HYP/PA11, and this steep decrease in the melt viscosity can be associated to the hydrolyse reaction of nylon for high pulp fibre moisture content at high temperature. In addition to the low processing temperature, the melt viscosity of the biocomposite using the Brabender mixer approach increases with increasing shear rate, and this stability in the increase even at high shear rate for high pulp moisture content is associated to the presence of inorganic salt lithium chloride which creates the hydrogen bonds with pulp during the compounding process.

Nutrient Accumulation and Distribution in Cotton Promoted by Removal of Mulch Film

Plastic film mulching affects changes in nutrient contents in soil and absorption and utilization of nutrients in plants were by changing hydrothermal condition of soil.The temporal and spatial variation of the total soil salt and nutrient contents with mulch film removed at three different times during the early cotton growth stage and its effects on nutrient absorption and accumulation in cotton plants were studied over 2015-2017.The film removal treatments reduced salt accumulation in normal rainfall year(2017).Film removal increased contents of soil organic matter,the total phosphorus and available potassium at the end of growth stage,increased contents of soil hydrolyzable nitrogen and the total nitrogen in the surface soil layer(0-10 cm),and increased the total nitrogen contents in the deep soil layer(40-50 cm).Film removal increased accumulation of nitrogen and phosphorus nutrients in cotton plants in 2017 and accumulation of nitrogen,phosphorus and potassium nutrients in cotton plants in heavy rainfall year(2016).These experimental results indicated that removal of mulch film at an appropriate and targeted time in the bud stage of cotton promoted nutrient absorption.

The status quo of radon concentrations and mitigation measures in underground working places of China

By using solid-state nuclear detectors, the air radon concentrations at 87 underground working places were measured during spring, summer and winter, respectively. The survey covered 23 cities whose annual radon concentrations range from {14.9} to {246.4} Bq·m{-3} with an overall arithmetic mean value of {106.7} Bq·m{-3}. The average annual effective dose received by people working in these underground working places was {1.6} mSv, hence the lifetime fatality risk was {1.2}×10{-4}. Fujian Province had the highest radon level during the survey. It is better to reduce the radon concentration heavily in summer because of higher radon concentration than in winter.

Recharge processes limit the resource elements of Qarhan Salt Lake in western China and analogues in the evaporite basins

The Qarhan Salt Lake(QSL)in western China is K-Sr-Li-B-Br-Rb multi-resource coexisting Quaternary brine deposits.Significant research efforts have been directed to the origin of K-Li resources and evolutionary history of the QSL.However,the study on the different sources,recharge processes,and differential distribution patterns for these resource elements in brine deposits is still inadequate.Therefore,we measured Li-B concentrations and H-O-Sr-B isotopic compositions of different waters(river,spring,and brine)from the QSL,combined with the reported K-Sr contents and multiple isotopes of waters,to discuss the recharge,source of K-Sr-Li-B and their spatial distributions,by analogy with other evaporite basins in the world.The results show that:(1)the K-Li-B-Sr elemental concentrations of brines and their spatial distribution in the QSL are diverse;(2)high K and Sr values are distributed in Dabuxun and Qarhan sections,respectively,which are controlled by Ca-Cl springs in the northern QSL;on the contrary,Li and B values are enriched in the Bieletan section and are charged by thermal springs in the Kunlun Mountains;(3)the formation and evolution of Ca-Cl and thermal springs constrain fundamentally on the recharge processes of K-Sr and Li-B elements in the terminal salt lakes of the Qaidam Basin(QB);(4)some analogues of recharge processes limit the resource elements of the QSL and other salt lakes(Da Qaidam,Lop Nur,Zhabuye,Atacama,and Guayatayoc)in the world provides a reference for the resource exploration in deep formation waters in the evaporite basins.

外源物质对低盐罗非鱼糜蛋白构象及体外消化特性的影响

以微波超声波辅助制备的低盐罗非鱼糜凝胶为研究对象,分析谷氨酰胺转氨酶(TGase)、羟丙基二淀粉磷酸酯(HDP)、结冷胶和三者的复配物(THG)对其水分分布及蛋白质构象的影响;并通过体外模拟消化实验,探究不同外源物质对微波超声波辅助制备的低盐罗非鱼鱼糕体外消化特性的影响。结果表明:添加THG后,鱼糜结合水和不易流动水较空白组分别增加98.71%和14.75%,自由水含量显著减少(P<0.05);THG促进了α-螺旋向β-折叠、β-转角和无规则卷曲结构转化。与空白组相比,添加0.4%TGase和THG对低盐罗非鱼糕的胃排空速度、蛋白体外消化率及蛋白水解度均有正面作用;其中THG可显著促进蛋白质分解成粒径较小的聚集体(P<0.05),经胃-十二指肠消化结束后的消化产物颜色更加透明清晰,从激光共聚焦显微镜可观察到THG组的红色荧光亮点显著减少,反映其蛋白被消化得较为完全。由此可见,在THG的作用下,鱼糜中水分子与蛋白质结合更紧密,相对于单一的外源物质,THG更加明显地改变了蛋白质的构象,且更有利于疏水蛋白基团的暴露和蛋白间的相互作用,且对鱼糕的消化有促进作用。本研究的结果为罗非鱼糜凝胶特性研究及罗非鱼糕类食品的开发与应用提供理论参考。

博孜-大北区域断裂活动的差异性及其对油气聚集的指示意义——来自天然地震及数值模拟的启示

本文针对博孜-大北地区的天然地震活动与分布进行统计分析,结果显示博孜与大北区域的地震分布存在明显差异性。博孜地区的天然地震呈现出山前向盆地方向减少的特征,而大北地区的地震活动主要聚集在靠近盆地的盐下冲断楔前部。通过对博孜-大北区域盐下断裂活动的定量分析和模拟,发现大北地区受到厚盐层沉积的影响,在盐下冲断楔前部区域出现持续的强断裂活动区,形成盐下断裂乱序传播模式;而博孜地区断裂自山前向盆地方向递进传播,其活动性逐渐减弱。研究结果表明,盐下断裂活动和天然地震分布具有良好的相关性,该地区盐下断裂活动的强弱是其天然地震分布的主要控制因素。大北盐下冲断楔前部区域断裂的持续活动导致该区域天然地震高频活动,而博孜区域盐下冲断楔前部区域断裂活动较弱,天然地震活动频率相对较低。区域油气勘探结果显示,地震活动对油气分布具有指示意义。博孜冲断楔前部区域的博孜1构造区具有断裂活动弱、地震频率低、油气藏保存条件好以及整体连片含气等特征,是油气勘探的有利区域。

破坏与建设:论张謇盐业改革之道

盐乃国之重器,关系着国计民生。张謇关注盐业改革三十余年,始终遵循“破坏与建设”并行的改革之道:破坏两淮盐业生产之“散”,主张建厂聚煎,统一管理;破坏专商引岸制度,主张就场征税,自由贸易;破坏产盐区划,主张因地制宜,盐垦兼营。围场聚制、就场征税、垦进盐退,这一系列举措体现了张謇对盐业改革的深远考量。仔细审视张謇的盐业改革方案和实践,他的改革从未单纯停留在“破坏”旧有体系,相反,他对于“建设”成效怀有强烈的热情和期待,旨在通过改革实现更加高效和公平的盐业生产和管理体系,从而解决国计民生问题。

内蒙古典型旱区盐湖盆地浅层地下水污染风险评价

为明晰内蒙古阿拉善盟吉兰泰盐湖盆地浅层地下水污染特征及评估地下水饮水安全风险等级,采集了盐湖盆地研究区土壤表层(0—10 cm)样品56个,地下水样品127个,检测分析土壤中重金属元素Cu、As、Pb含量及水样中Cr、Hg、As、F^(-)、NO_(2)^(-)、NO_(3)^(-)含量.运用地下水风险评价概念模型,将地下水脆弱性、地下水污染物容量及土壤毒性污染物潜在生态危害评价有机结合,对地下水污染风险展开评价.借助ArcGIS软件进行克里格插值绘图,探析盐湖盆地浅层地下水风险的空间分布特征.结果表明:盐湖盆地地下水脆弱性指数范围为4.80—5.30属于中等脆弱性,吉兰泰盐湖东南部和吉兰泰镇西北部脆弱性高于其他区域;地下水样品中重金属Hg的含量在《地下水质量标准》中Ⅲ类水水质标准范围内,其他元素均有超标现象,其中F^(-)超标率最高,为62.20%,Cr、As、F^(-)、NO_(2)^(-)、NO_(3)^(-)变异系数分别为125.40%、183.50%、178.70%、248.70%、280.70%,属于强变异性,受外界因素干扰较为明显,研究区地下水特征污染物分布较为集中,主要分布在盐湖盆地的东南部;土壤中重金属Cr、Hg、As的平均含量分别为26.32、0.17、11.77 mg·kg^(-1),与内蒙古当地土壤背景值相比较,Cr的平均值在背景值范围内,而Hg、As的平均值分别超出背景值4.25、1.57倍,土壤综合潜在生态危害指数为188.32,属于中等潜在生态危害,在盐湖盆地中有41.07%的样品点属于中等、强、很强潜在生态危害;盐湖盆地地下水污染风险等级分布不同与含水层脆弱性指数、特征污染物容量指数及潜在生态危害指数有关,较高污染风险区和高风险区分布在锡林高勒镇西部,较高风险以上的面积占研究区面积的25.77%,古拉本敖包镇、贺兰山的东南部在中风险范围内,中风险区面积占研究区面积的11.49%.

中国含盐盆地卤水溴元素分布与物源

中国含盐盆地赋存丰富的盐湖卤水和深部卤水资源,卤水中富集溴(Br)元素,具有潜在的开发利用价值。Br作为盐湖卤水中重要的资源元素,目前对其分布规律和物质来源的系统对比研究鲜有报道。本文以柴达木盆地察尔汗盐湖四个区段晶间卤水为研究对象,分析整个湖区Br元素分布规律和物质来源,对比中国不同含盐盆地卤水Br资源变化和物源联系,并总结不同卤水开发利用价值。结果表明:①察尔汗盐湖Br含量呈东高西低特征且不同区段差异明显;②别勒滩和达布逊区段卤水低Br受河流补给并经蒸发富集,而察尔汗和霍布逊区段高Br受北部断裂带上涌富Ca泉水补给;③中国含盐盆地(柴达木盆地、库车盆地、江汉盆地、吉泰盆地)大部分深部卤水高Br值主要受水-岩反应、沉积物及有机质中Br的解吸获得;④盐湖晶间卤水虽远不及深部卤水Br含量高,但其优点在于便于开发、综合利用率高,尤其浓缩卤水及老卤中的Br含量可预见性的高于工业开采品位,是当下和今后值得关注的资源。

青藏高原盐湖卤水中溴的分布特征及来源初探

溴是完备工业体系的关键必备元素。盐湖卤水是溴的重要来源。青藏高原盐湖众多,富含钾、锂、硼等资源元素,开发潜力巨大。然而,目前针对青藏高原盐湖溴浓度、分布特征及其物源的研究仍然薄弱。本次研究采集了26个青藏高原盐湖表卤水样品并分析其溴浓度,进一步总结其他64个已报道盐湖数据,系统分析了青藏高原盐湖溴浓度分布特征,并进一步探讨了溴的可能物源。结果表明:青藏高原盐湖表卤水溴分布在0.5~246.8 mg/L之间,平均为41.1 mg/L,其中,碳酸盐型盐湖卤水平均溴浓度最高(47.0 mg/L),且集中分布在高原南部,而氯化物型盐湖平均溴浓度最低(30.1mg/L),盐湖溴浓度呈现自南向北降低的趋势;青藏高原盐湖中溴有多种来源,高原南部富溴盐湖溴的来源可能主要与热泉补给有关,而柴达木盆地盐湖高溴来源可能主要与深部地层水(如油田水、背斜构造裂隙孔隙水、砂砾孔隙卤水、气田水等)补给有关。

吉兰泰沙漠盆地高氟地下水分布规律与形成机理

【目的】分析吉兰泰沙漠盆地高氟地下水分布规律,探究绿洲径流区地下水超采对氟解离、迁移和富集的影响机理。【方法】基于SPSS24.0和ArcGIS软件对水化学特征进行数据统计和空间分析;采用Piper三线图、离子比值、Gibbs图解与饱和度指数等方法,结合1980—2020年查哈尔滩绿洲地下水位监测数据和开采数据,探究其高氟地下水水化学特征及成因。【结果】(1)从山地补给区→绿洲径流区→沙漠盐湖排泄区,地下水化学具有分带规律,矿化度、钾离子、钠离子、F-质量浓度逐渐增大,F-质量浓度为0.2~3.4 mg/L;(2)盐湖区地下水F-呈环形岛状分布;沙漠盆地地下水化学的形成主要受含氟岩石的风化作用和蒸发浓缩等自然因素影响;(3)绿洲径流区地下水超采驱动吉兰泰盐湖劣质地下水入侵沙漠绿洲,灌溉回归水的淋滤作用改变了土壤氟解离和迁移模式,导致地下水咸化、高氟化。【结论】综上可知,盐湖排泄区和绿洲径流区地下水氟富集反映了沙漠盆地水文生态环境退化,应采取管灌、滴灌等节水灌溉方式和压缩耕作面积等措施,使查哈尔滩绿洲年地下水开采量减少至700×10^(4)m^(3),以抑制吉兰泰沙漠盆地绿洲灌区的地下水高氟化趋势。