共查询到19条相似文献，搜索用时 109 毫秒
1.
长江中游鄂东南铜矿集区土壤铜环境地球化学特征 总被引：11，自引：1，他引：11
对鄂东南铜矿集区的山间谷地、长江冲积平原和低山丘陵三种地形土壤的系统测定表明：（1）土壤母质是影响土壤全量铜的主要因素，土壤有效态铜总体上受土壤全量铜的制约；在相同地理和气候条件下，土壤pH值是控制铜垂向分布的重要条件之一；中生代含铜花岗闪长岩是长江中游沿江铜矿庥区内区域土壤铜污染的主要自然源。（2）矿集区内土壤铜污染主要有自然污染和人为污染两类，两类土壤污染在土壤全量铜、有效态铜和铜含量垂向分布及土壤pH、R（电导）等理化性质方面有着明显的区别。 相似文献
2.
根据石家庄污灌区土壤的平面和垂直剖面土壤样品中As含量数据,制作了As分布图,总结当地As元素分布特征。结果表明:石家庄污灌区内表层和深层土壤中As的分布都受到强烈的外源影响:表层As的分布受到污水排放源位置的控制,深层土壤也受纳了从上层向下迁移的外源As,在表层和深层都形成了若干高值区,各高值区具有独立成因;垂向分布上As主要富集在深部粘土层。 相似文献
3.
承德伊逊河钒钛磁铁矿小流域土壤重金属地球化学基线及生态风险累积效应 总被引：2，自引：0，他引：2
以承德市伊逊河红旗钒钛磁铁矿小流域为例,通过参比元素标准化法、垂向剖面似背景值法确定小流域矿集区土壤12种重金属的地球化学基线,并与不同空间尺度流域的重金属地球化学基线进行对比;采用确定的基线值结合地累积指数法、地统计学、生态风险指数法和GIS叠加法对流域土壤重金属潜在生态风险和累积程度进行了评价。结果表明:钒钛磁铁矿矿致异常元素地球化学基线值具有明显的流域尺度效应,其值随着流域空间尺度的缩小而升高;在已开采矿集区小流域土壤重金属污染生态风险评价时,可选取其上一级流域地球化学基线值作为标准。伊逊河红旗矿集区小流域V、Ti、Co、Ni和Cr元素基线值高于滦河流域,As、Pb、Zn和Cd元素基线值与滦河流域相近,Mn和Hg元素基线值略低于滦河流域,Cu元素基线值略高于滦河流域。表层土壤重金属污染累积程度由强至弱为:Cu>Cr>Ti>Cd>Co>V>Ni>Zn>As>Hg>Mn>Pb;表层土壤重金属综合潜在生态风险指数RI范围为65.89~237.70,总体生态风险水平属低风险水平。深层土壤重金属总体污染累积程度和综合潜在生态风险总体弱于浅层土壤。流域土壤重金属综合潜在生态风险累积程度空间分布与流域地貌特征具有明显的耦合关系,重金属空间迁移主要受水力作用驱动控制,土壤重金属污染来源主要为矿业活动,同时受岩石风化和土壤侵蚀等自然因素影响。 相似文献
4.
《中国煤炭地质》2019,(Z1)
柿竹园矿区有色矿产资源丰富,矿山地质环境问题严峻,土壤重金属污染尤其突出。本文使用数理统计分析等方法对研究区土壤环境介质中的重金属元素的组分含量和空间分布特征进行分析。通过组分含量特征分析可知:土壤重金属呈正偏离态分布,Pb、Cd、As、Cu、Zn属于空间强变异,Cr、Hg属于空间弱变异; Cd-Zn、Cu-As、CuZn、Cu-Cd、Cd-As相关性显著,表明土壤Cd、Zn、As和Cu主要受矿山开采活动控制。通过空间分布特征分析可知:矿集区易向土壤中释放Ni、Cu、Cd、Zn、Pb和As并且输入量较大,尾砂库、矿集区和选矿厂向土壤中释放Cr的能力较小;尾砂库、矿集区和选矿厂没有向土壤中释放Hg。研究结果对柿竹园矿山流域的水资源、土地资源、矿山资源及生态资源的开发与保护具有借鉴意义。 相似文献
5.
云南省土壤As、Cd元素地球化学特征 总被引：6，自引：0，他引：6
据云南省1：20万水系沉积物测量及部分土壤测量成果,总结了不同介质、各类土壤与母岩的As、Cd的地球化学背景及异常分布特征,分析讨论了As、Cd的富集规律及来源。认为云南省As、Cd土壤背景含量高于水系沉积物的背景含量,并远远大于地壳平均含量。土壤中As、Cd含量以石灰土及石灰岩最高,是全省土壤平均值的1．5倍,随着pH值的升高,背景含量呈上升态势。As、Cd地球化学高值区与岩溶发育区对应较好。全省共圈出7个As异常带和12个Cd异常区,而面积、幅值最突出的As、Cd元素异常均位于石漠化重度发育的滇东南地区。As、Cd异常主要来源于高背景含量的母岩（碳酸盐岩）,其富集的主要原因是由于高pH值及高CEC值的碳酸盐岩土壤,质地黏重,有机质含量高,As、Cd迁移速率降低,被持留的量增大,造成我省碳酸盐岩发育区,土壤As、Cd高度富集． 相似文献
6.
山西临汾-运城盆地土壤中As含量的变化规律 总被引：2，自引：0，他引：2
通过对临汾-运城盆地表层和深层土壤中As含量变化规律的研究,发现表层土壤的As含量稍高于全国土壤的背景值,不同相态的含量差异较大。土壤pH、磁化率、有机质、粘粒含量等理化性质对不同形态的As有着不同程度的影响：研究区水溶态的As受土壤pH值的控制,腐殖质结合态的As与有机质呈明显的正相关关系,磁化率、粘粒含量与土壤As的含量都有明显的正相关关系。研究结果表明,As与Fe、Mn、Cu、Zn、Mg、K、F等元素的相关性非常显著,说明研究区表层土壤中的As主要是自然成因的。进一步的回归分析表明,土壤的As含量随着铁氧化物、氢氧化物和硫化物含量的增加而增加。研究区土壤As的纵向分布特点是中层多、上下层少,这可能与研究区As的污染状况、土壤的碱性环境、植物的吸收作用、磷肥的施用等因素有关。 相似文献
7.
通过对山东省小清河流域土壤重金属污染现状的调查研究,查明土壤重金属污染状况,元素来源和分布迁移规律,从而为该区土壤重金属污染的科学治理提供有效依据。研究发现,小清河沿岸地区的重金属污染主要表现为As、Cd、Cr、Ni等元素的污染;依据内梅罗污染指数评价方法发现研究区存在重金属污染的土壤总面积为880.5 km2,未受到重金属污染的土壤面积为1 822.1 km2,分别占全区总土壤面积的32.58%和67.42%,其中上游的济南市城区北园镇至华山镇区域的小清河两岸是重污染区。对小清河流域土壤重金属来源的探析表明,大气干湿沉降是土壤重金属污染的主要来源;土壤重金属的生物有效性评价显示重金属元素Cd的活动态比例高达56.17%,活化迁移能力强,是该区对生态环境危害性最大的污染因子。此外,As、Cd、Cr、Pb等重金属元素的活动态含量明显受pH值和Corg含量的制约,在低pH值、高Corg含量的土壤区应高度重视As和Cd的污染问题。 相似文献
8.
矿业活动会促进重金属向生态系统扩散,并在周边农田土壤中累积而引发潜在生态风险。豫西金矿集区矿业生产历史悠久,但在长期的矿产资源开采、选冶、加工生产过程中,缺乏对矿区周边农田土壤重金属元素的累积、空间分布和生态风险的关注,矿业活动对环境的影响程度尚不清楚。为掌握该矿集区矿业活动对周边农田土壤重金属的影响程度,支撑服务矿集区生态修复和周边农业安全生产,本文在金矿集区周边农田采集375件土壤样品,采用冷蒸气原子荧光光谱法(CV-AFS)、氢化物发生原子荧光光谱法(HG-AFS)、电感耦合等离子体发射光谱/质谱法(ICP-OES/MS)检测了样品中Cu、Pb、Zn、Ni、As、Hg、Cd、Cr重金属元素含量。用地累积指数法和潜在生态风险指数法研究了矿集区周边农田土壤中重金属元素的累积特征、空间分布和生态风险,分析评价了矿集区矿业活动对周边农田土壤重金属的影响。研究结果表明：(1)矿集区周边农田土壤中Cu、Pb、Zn、Ni、As、Hg、Cd、Cr含量平均值都低于国家农田土壤重金属污染风险筛选值,但均高于背景值,分别是背景值的1.47、3.24、2.06、1.05、1.03、1.52、2.77、1... 相似文献
9.
10.
11.
To predict the long-term behavior of arsenic(As) in soil profiles,the solid-solution partitioning of As was studied in four paddy soil profiles obtained from agricultural areas in Chengdu Plain,Southwest China.Paddy soil profile samples were collected and soil solution samples were extracted.Total As contents in soil solution and soil solid were analyzed,along with the soil solid phase properties.The As in soil solution was significantly higher in the upper layer(0—20 cm) and had a definite tendency to decrease towards 40 cm regardless of the sampling locations.When the concentration of arsenic in soil solution decreased,its content in solid phase increased.Field-based partition coefficient(K_d) for As was determined by calculating the ratio of the amount of As in the soil solid phase to the As concentration in the soil solution.K_d values varied widely in vertical samples and correlated well with soil pH,total organic carbon(TOC) and total As. The results of this study would be useful for evaluating the accumulation trends of arsenic in soil profiles and in improving the management of the agricultural soils. 相似文献
12.
《Applied Geochemistry》2004,19(11):1785-1800
Historical Au-ore exploitation at the Chéni mine in the Massif Central, France, generated 525,000 tonnes of finely ground mill tailings deposited in a heap that has spread with time into three settling basins. The tailings, which are rich in quartz (80%), mica and clay minerals (10% of illite, smectite, kaolinite and chlorite), feldspars (5%) but poor in carbonates (<1%), also contain sulphides (around 5%, mainly pyrite and arsenopyrite). Arsenic content of the tailings is around 6 g kg. This paper describes the geochemistry of drainage waters, with special attention paid to in situ values of the three major redox couples, namely Fe(II)/Fe(III), As(III)/As(V) and S(IV)/S(VI). The water samples range from acidic and oxidized (pH 2.9, Eh +700 mV) to moderate pH and weakly reducing (pH 7.6, Eh 15 mV). The waters are rich in SO4 and Ca and have variable As (0.05–95 mg L−1) and Fe concentrations (0.07–141 mg L−1). Reduced As(III) species predominate over As(V) species (As(III)/As(V) up to 21), whereas oxidized forms of Fe and S are favoured (Fe(II)/Fe(III) up to 0.5, and S(IV)/S(VI) up to 1).Thermodynamic calculations were performed with the PHREEQC and EQ3NR codes based on a revised As database to evaluate saturation indices (SI) of the waters in relation to the main minerals and define which redox couples control the redox state of the system. The important role of carbonates, though only present in small amounts, explains the acid buffering generated by the oxidation of sulphides for waters in the pH 7–7.5 range. Measured Eh appears to fall between the calculated Eh of the Fe(II)/Fe(III) couple and that of the As(III)/As(V) couple, illustrating redox disequilibrium. 相似文献
13.
In situ data on the daily dynamics of pH, [O2], and Eh values at five water layer depths were obtained. Some regularities have been established: All these parameters are characterized by significant diurnal fluctuations and their daily cyclic recurrence; the diurnal cycles of pH and [O2] nearly coincide (they show close extreme points on the time scale); the Eh cycles are less distinct and antisymbatic to the pH and [O2] cycles, but typical Eh extremes sometimes lag by 2–3 h. These data were analyzed using the principle of equilibrium locality and partiality. The main flows of O2 and CO2 in the system have been revealed with regard to the water layer–atmosphere gas exchange, absorption of CO2 by phytoplankton in the photic layer, breathing of phyto- and zooplankton, birth and die-off of biota, settling of mortomass, and redistribution of detailed components within the water layer as well as between it and the bottom sediments. On the basis of the results obtained, the known technique for estimating the content of primary photosynthesis products (Bruevich's method) was corrected. The used generalized algorithm of chemical thermodynamic analysis of the substance state in aqueous systems can be applied to waters of different classes as well as any surficial waters if Eh, pH, and [O2] are taken into account. 相似文献
14.
Priyanka Ghosh 《Computers and Geotechnics》2009,36(1-2):342-351
This paper presents the pseudo-dynamic analysis to determine the seismic vertical uplift capacity of a horizontal strip anchor using upper bound limit analysis. However, in the literature, the pseudo-static approach was used by few researchers to compute the seismic vertical pullout resistance, where the real dynamic nature of earthquake accelerations cannot be considered. Under the seismic conditions, the values of the unit weight component of uplift factor fγE are determined for different magnitudes of soil friction angle, soil amplification, embedment ratio and seismic acceleration coefficients both in the horizontal and vertical directions. It is observed that the uplift factor fγE decreases significantly with the increase in seismic accelerations and amplification but increases with the increase in embedment ratio. The results are compared with the existing values in the literature and the significance of the present methodology for designing the horizontal strip anchor is discussed. In presence of vertical earthquake acceleration and amplification of vibration, the present values of fγE compare reasonably well with the existing pseudo-static values obtained by modifying the horizontal acceleration coefficient. 相似文献
15.
武山铜矿北矿带ICu矿体砷的分布规律 总被引：1，自引：0，他引：1
武山铜矿化矿带ＩＣｕ矿体是高砷矿体,分析了砷在各金属矿物中含量及分配情况和含砷量的分布规律,确定了高砷采场或矿段,指出了进行矿石质量控制,配矿管理的降砷途径。 相似文献
16.
The excess pore water pressure distribution (u) induced by the penetration of a piezocone into clay and its dissipation behaviour have been investigated by laboratory model tests, theoretical analysis and numerical simulation. Based on the results of the tests and the analysis, a semi-theoretical method has been proposed to predict the piezocone penetration-induced pore pressure distribution in the radial direction from the shoulder of the cone. The method can consider the effect of the undrained shear strength (su), over-consolidation ratio (OCR) and rigidity index (Ir) of the soil. With a reliably predicted initial distribution of u and the measured curve of dissipation of pore water pressure at the shoulder of the cone (u2), the coefficient of consolidation of the soil in the horizontal direction (ch) can be back-fitted by analysis of the pore pressure dissipation. Comparing the back-fitted values of ch with the values directly estimated by a previously proposed method indicates that the previously proposed method can be used reliably to estimate ch values from non-standard dissipation curves (where u2 increases initially and then dissipates with time). 相似文献
17.
Areti Gianni Miltiadis Zamparas Ioannis T. Papadas George Kehayias Yiannis Deligiannakis Ierotheos Zacharias 《Aquatic Geochemistry》2013,19(1):77-95
The balance between physicochemical processes, influencing vertical and temporal distributions of metal compounds in one relatively isolated anoxic environment, constitutes the objective of the present work. Ion activity product (IAP) was calculated for manganese and iron sulfides, in order to define the metal sulfide forms that control Fe and Mn solubility in the bottom waters of anoxic lagoons. Iron solubility depended on amorphous FeS formation, while manganese sulfides were a minor component in a solid solution lowering its solid-phase activity. A theoretical physicochemical model was developed for the iron speciation, based on experimental pH and redox potential data. A very good match was achieved for the measured and the theoretical total dissolved iron, at all depths. The dominance of oxidant iron species Fe(OH) 3 ? in the surface waters and their sequence by FeSH+ and FeSaq in the deeper layers brings out the influence of physicochemical parameters (dissolved oxygen, sulfide, pH and Eh) in vertical distribution of dissolved metal species, in anoxic/hypoxic basins. Based on these findings, we can conclude that the distribution of manganese and iron is of special interest, not only because these are the indicators of redox conditions but also for the role of their oxidized/reduced forms in the formation of the biogeochemical structure of redox zone. 相似文献
18.
19.
广西中东部9县区农田土壤As输入通量研究 总被引：1，自引：0，他引：1
对广西中东部9县区农田土壤中的As输入通量进行了初步研究。综合各方面因素,计算获取了大气干湿沉降、施肥和灌溉水输入通量。结果表明,研究区大气干湿沉降和施肥As输入通量基本相当,平均值分别为9.92 g/(hm^2·a)和7.83 g/(hm^2·a),灌溉水通量最高,平均值为14.98 g/(hm^2·a),三者对土壤As污染的贡献率分别为30.31%、23.92%和45.77%。9个不同县区大气干湿沉降、施肥和灌溉水As输入通量占比略有不同,其中6个县区灌溉水和施肥输入通量占主导地位,另外3个县区大气干湿沉降输入通量比例较高。因此,灌溉水是研究区农田土壤As的主要输入途径,应重视灌溉水水质控制。在未考虑农田土壤As输出通量的情况下,以当前的As年平均输入通量估算得到耕层土壤As的质量分数每年升高0.01 mg/kg。与土壤As含量现状相比,As年增量比例很小,因此判断在短期内,外源输入对土壤As分布现状影响不大。该区土壤p H值较低,铁氧化物含量较高,因此外源输入农田土壤的As生物有效性较低。 相似文献