石柱黄连及根际土壤中矿质元素特征分析

研究石柱黄连不同器官及其根际土壤中矿质元素特征,探究黄连根茎矿质元素间及其与土壤环境的相关性。采用电感耦合等离子体质谱法(ICP-MS)、电感耦合等离子体发射光谱法(ICP-OES)及原子荧光光谱法(AFS)测定了15组石柱黄连植株和根际土壤中18种矿质元素含量,所得数据运用SPSS 22.0统计软件分析。石柱黄连根际土壤中锰、磷、镁、镉、汞等元素含量的变异性较大,部分采样点土壤中镉含量超过农用地土壤污染风险筛选值。在检测的18种元素中,黄连植株中钙、镁、磷、钾含量最高,其次是铁、锰、锌,再次是锶、铜、镍,最后是铅、钒、钴、镉、钼、铬、砷、汞。须根对大部分矿质元素的富集能力强于根茎或地上部;黄连根茎对锌的富集能力强于须根或地上部;地上部对钙、磷、钾、铬的富集能力强于须根或根茎。Spearman分析表明黄连根茎矿质元素间、黄连根茎与土壤中矿质元素有一定相关性,部分具有统计学意义(P＜0.05)。石柱黄连不同器官中矿质元素含量有明显差异,以此建立的指纹图谱可用于区分黄连根茎及须根的粉末样品;黄连根茎中矿质元素间主要表现为协同作用,黄连根茎与土壤中矿质元素既有协同作用又有拮抗作用。     

不同环境条件对土壤-巴戟天系统重金属分布的影响

采用AA-6800型石墨炉原子吸收光谱仪研究了土壤-巴戟天系统中铅的分布情况,包括不同地段、不同土壤类型、不同土壤pH值对土壤-巴戟天入药部位根和果实中铅的含量影响。实验结果表明,环境条件变化对土壤-巴戟天系统铅含量有一定的影响,其中土壤的pH值对土壤中的有效铅浓度及巴戟天的铅含量影响较大。     

土壤铜污染的微生物及酶学指标研究

通过室内培养试验,研究了土壤铜污染对土壤微生物基础呼吸及土壤脲酶、脱氢酶、酸性磷酸酶的影响。结果表明,土壤微生物基础呼吸在低水平铜（≤100mg／kg）添加下呈现出先上升后下降的趋势,而随着土壤铜添加水平的进一步提高（〉100mg／kg）,微生物基础呼吸作用迅速增强;土壤脲酶则随着铜含量的增加呈现出不断下降趋势,土壤磷酸酶活性则在低水平下上升而随着添加水平的进一步提高迅速降低。可见,这两种酶对土壤铜毒害反应灵敏,可作为土壤铜污染评价的指标;而土壤脱氢酶则对铜含量的变化没有表现出明显的统计规律性,不适宜作为土壤铜污染评价的酶学指标。     

Study of the Influence of Different Diphenol Compounds on Soil Microbial Activity by Microcalorimetry

Microcalorimetry was applied to follow the toxic effects caused by different diphenol compounds on microbial activity of Chinese fir soil. The activity of the microorganisms in soil was stimulated by adding 0.3 mL of a nutrient solution containing 2.5 mg of glucose and 2.5 mg of ammonium sulfate and the measurements were performed under a 35% controlled humidity at 28°C. Power‐time curves recorded on a microcalorimeter were followed by increasing the amount of diphenol compounds, which affected directly the total thermal effects evolved by the microorganisms. The curves showed a synergism on total thermal effect obtained by the addition of 2000 mg·kg^?1 of resorcinol, causing a consumption of resorcinol by the microorganisms as a new source of nutrients. Above this dose, the total thermal effect decreased exponentially. However, the addition of catechol and hydroquinone caused the total thermal effects to decrease directly. It was concluded that the increase in the diphenol concentration strongly affected the microbial life in this ecosystem. Microcalorimetry appears as a suitable technique to carry out both qualitative and quantitative comparative studies of microbial activity in soil.     

土壤微生物ATP、脱氢酶和尿素酶活性的ED50值评价外源镧的生物毒性

０IntroductionRareearthsarenowappliedwidelyinChina，whichcanimprovecropsyieldsandthetheirqualit－ies犤１犦．Thebeneficialeffectsmaybeduetothestimu－latoryeffectsoftheseelementsonthenutrientuptakebyplantsorontheincreasingofchlorophyllsynthesisintheplants犤２犦．Whilealotofresearcheshavebeendoneontheimprovednutritionofcropsafterapplica－tionofrareearths，muchlessattentionhasbeenpaidtothedeteriorationofsoilqualityduetotheapplicationofrareearthsforyears犤３犦．Scientistshavediscoveredthataccumula…     

镧对红壤硝化、磷转化和酚分解作用的影响

通过室内培养和盆栽试验研究了La对红壤硝化作用,磷转化作用和酚分解作用的影响,低浓度下,La对土壤的硝化作用和磷转化作用均有某些刺激作用,但随着浓度的升高产生抑制作用并不断增加,La对土壤酚分解作用表现为剧烈的抑制作用,并随着浓度的升高,抑制作用不断增强,随着培养时间的延长,La对土壤硝化作用和酚分解作用的抑制作用有降低的趋势。     

Temperature effects on the point of zero charge and isoelectric point of a red soil rich in kaolinite and iron minerals

The effects of temperature (373–1373 K) on the point of zero charge (PZC) and isoelectric point (IEP) of a red soil rich in kaolinite and iron minerals were studied. PZC values of the soil treated at 373 and 573 K indicated the presence of iron oxide. The soil calcined between 773 and 1173 K shows a PZC almost coincident with the respective values of kaolinite. At 1373 K, the PZC of the soil is nearer to the value of iron oxide. In the entire temperature range studied the PZC values were lower than the IEP values. An approach of PZC and IEP values was observed after a partial removal of iron oxide by the dithionite-citrate-bicarbonate (DCB) method. The analyses of the PZC and IEP values, of electron probe micro analysis (EPMA) data and of specific surface areas evidence a specific adsorption of iron oxide on kaolinite. Finally, the dissolution sequence of iron and aluminium contained in soil was determined using hydrochloric acid.     

Laboratory studies on waste water sludge application for acid soil remediation

In this work the effects of sludge disposal on pH values, buffer capacity and adsorption capacity of an acid soil were studied. A stabilized waste water sludge and a paper mill sludge were employed; the pH values of both sludges were higher than 8. The observed differences between soil-urban sludge and soil-paper mill sludge systems can be ascribed to the nature of the compounds present in the sludges and adsorbed on the soil. Both kinds of sludge are able to modify the natural pH of the soil, the buffer capacity and its capacity to retain metal. These modifications increase with increasing soil-sludge contact time and are higher for paper mill sludges. Temperature affects only the modifications due to urban sludge treatment.     

A PRELIMINARY STUDY ON THE IMPACT OF MESOSCALE IRRIGATION OVER ARID LAND ON MESOSCALE CLIMATE

The present study investigated the modification of mesoscale inhomogeneous distribu-tion of soil wetness, resulting from mesoscale irrigation over arid or semiarid lands in mid-latitude in the later summer or early autumn, on mesoscale climate under conditions withand without synoptic flow influence, using an interactive model between soil and atmo-sphere. The simulations indicated that after a mesoscale irrgation, a wet soil breeze circu-lation was thermally forced, which was, in many features, similar to that of the sea breezecirculation. The influence of synoptic flows on the structure of thermally--induced wet soilbreeze circulation was also discussed.     

Development of Resin Membranes as a Sensitive Indicator of Heavy Metal Toxicity in the Soil Environment

Abstract

Ion exchange resins in contact with soil can act as a sink for metal cations, thereby simulate the action of plant roots. Ion exchange resins in membrane form offer additional advantages in ease of use and handling. A procedure was developed to assess the bioavailability of four heavy metals Cd, Cr, Ni and Pb via direct in soil burial. A growth chamber experiment with three representative crops (oats, radish and lettuce) was set up to determine the phytotoxic levels of the four heavy metals. The critical levels varied widely from crop to crop, and soil to soil. Lettuce was most sensitive to high concentration of metals. The toxic effects are more pronounced on sandier textured soils.     

镧对红壤微生物碳、氮及呼吸强度的影响

室内培养试验表明,La对红壤微生物碳氮及呼吸强度均表现为抑制作用,并随浓度增加,抑制作用增强,在100mg/kg^-1时达到显著水平,随着培养时间的延长,La对微生物碳氮和呼吸强度的有减少的趋势,但短期内抑制作用难以消除,水稻盆栽试验表明,在低浓度时,La对土壤微生物碳氮和呼吸强度有少量刺激作用,但随着浓度的增加,则产生抑制作用并不断增强,在300mg.kg^-1时达到显著水平,土壤微生物量和呼吸强度可以作为评价稀土污染土壤的重要指标。     

土壤-植物体系稀土元素的分异现象

用仪器中子活化分析测定了从同一地点采集的9种不同植物根和叶中8个稀土元素（La,Ce,Nd,Sm,Eu,Tb,Yb和Lu)的含量，研究了稀土元素在植物根、叶及相应母土中的分布特征。结果表明，同一植物的根、叶和母土中稀土分布模式均有较大差异。生长在同一地点不同植物根中稀土分布模式非常相似，而叶中分布规模差别较明显。说明根对单一稀土元素的吸收主要取决于这个元素在土壤中有效态的含量，而在稀土从根到叶的运输和积累过程中出现的分异则由植物自身的结构特征决定。     

急倾斜煤层地下气化数学模型的研究

煤炭地下气化产气过程与气化炉体的温度分布和渗流条件密切相关。根据急倾斜煤层赋存条件和气化过程的特点，建立了急倾斜煤层地下气化数学模型。介绍了模型参数的确定方法，采用控制容积方法对模型进行了求解，并在模型实验的基础上，对计算结果进行了分析。从温度场分布来看，计算值略高于实测值，各测点相对误差基本均在10%以内。根据模拟计算结果，随着气化通道长度增加，煤气热值提高，但在还原区以后，提高的幅度减小，温度场对煤气热值产生显著影响。由于受温度的影响，在高温区，煤气组分浓度场实测值的变化梯度大于计算值。结果表明，模拟值与实验值能够较好地相吻合，说明对急倾斜煤层地下气化温度场和浓度场的数值模拟是合理的。     

A Thermogravimetric Approach to Study the Influence of a Biodegradation in Soil Test to a Poly(lactic acid)

Summary: An amorphous grade Poly (lactic acid) (PLA) was selected for an accelerated burial in soil test during 450 days. Thermogravimetric analyses were carried out to study the effects of degradation in soil on the thermal stability and the thermal decomposition kinetics. A single stage decomposition process is observed for all degradation times. It is shown that the thermal stability of PLA is slightly affected by degradation in soil. Concerning the study of the thermal decomposition kinetics, Criado master curves were plotted from experimental data to focus the study of the thermodegradation kinetic model.The kinetic methods proposed by Broido and Chang were used to calculate the apparent activation energies (Ea) of the degradation mechanism. These results were compared to the Ea values obtained by the method developed by Coats and Redfern in order to prove the applicability of the former methods to the kinetic study. As expected, non-linear tendency is found out for Ea variation along the degradation times, which can be explained as an evolution by stages.     

基于养分指标相关性的土壤有机质预测模型研究

为探究土壤间各养分指标间的相互关系,选取了天津市宁河区不同区域的种植土壤,基于行业标准规定的检测方法,对主要养分指标进行了测定,并研究各指标间的相关性。结果表明,各区域土壤pH值变异系数最小,整体均呈碱性;有机质、全氮及速效钾变异系数属于中等;有效磷的变异系数最高。各研究区域土壤有机质含量与全氮含量呈显著正相关(P<0.01),与pH值呈显著负相关(P<0.01),而与其他指标间不具备普遍且显著的相关性。基于多元线性回归分析建立了土壤有机质与全氮及pH值之间的预测模型,通过模型计算出的预测值与实际测定值的拟合性较好;另取土壤样品进行验证表明,预测模型具有良好的可靠性和准确性。     

Thermodynamic Characteristics and Mechanisms of Heavy Metals Adsorbed onto Urban Soil

The thermodynamic characteristics of heavy metals adsorbed onto urban soil and the relative adsorption mechanisms were studied by the batch experiment. The results show that there existed dynamic adsorption-desorption equilibrium processes of cationic and anionic ions of heavy metals onto urban soil, which may have an impact on the pH of the adsorption system. The amounts of heavy metals adsorbed onto urban soil increased with the increase of the equilibrium concentration, but their adsorption amounts were not the maximum adsorption amounts. The higher the pH was, the greater the adsorption capacity of the urban soil at the same equilibrium concentration was, and the adsorption amounts of heavy metals onto urban soil followed the order of Pb>Cu>Cd>Zn>Ni. There were coordination reaction, hydrolysis reaction, exchange reaction in the adsorption processes of heavy metals onto urban soil. With the increase of pH, the influencing degree of pH on the different reactions of heavy metals in the soil increased, meanwhile the effects of other physicochemical properties of soil on the adsorption of heavy metals were weakened.     

Using Surfactant System to Wash a Polluted Soil by Petroleum Derivatives in Egyptian Abu Madi Fields in Terms of Emulsification

The exploration and production activities of the natural gas in Abu Madi region (in middle delta) progressed in the last decade. The condensate hydrocarbon and formation water are bi‐products produced during the natural gas industry. The accompanied water contains 10–15% condensate (gasoline). This water with gasoline was drained into the Shehab El‐Din drain. The farmers were used this water to irrigate their fields. Great areas of the fields were out of order of planting as the result of gasoline pollution. This work concentrates on washing the polluted soil using locally prepared surfactant (LABSA‐Na) in the washing process. The soil sample was picked up from the Abu Madi field and was divided into pots (four pots for each treatment). The experiment was designed on the basis of polluting the soil by gasoline (condensate) from 1 to 10%. The washing process was carried out in presence of 0.1, 0.3, and 0.5% surfactant solutions. The control and blank sample were taken in consideration. The washed and the latent oil percentages were determined using the spectrophotometric method. After polluting and washing the soil, the pots were fertilized and planted by Zea Mays. The pots were irrigated twice a week. The length of plants was followed up. The obtained results cleared that, the efficiency of washing process increases with increasing of the pollutant percentage and also with increasing of surfactant concentration. The maximum washed oil (gasoline) was obtained at 10% gasoline and 0.5% surfactant concentration. The length of plants after 21 days of planting were; 0 (no planting), 24, 34, 39, 54, and 57 cm against polluted soil and planted (control) washed soil by water only; washed soil by 0.1%; washed soil by 0.3%; washed soil by 0.5% and no polluted soil (blank) respectively. These data revealed that, removing the hydrocarbon from the soil by washing using surfactants is the most effective method as the result of solubilization and emulsification of the hydrocarbon by surfactant which make it more removable.     

Prediction of Plant Contamination by Cadmium and Zinc Based on Soil Extraction Method and Contents in Seedlings

Abstract

Prediction of plant contamination on the basis of environmental conditions seems to be an important task. In order to assess the suitability of three soil extractants and seedlings as a prediction media for the content of Cd and Zn in mature plants, three independent pot trials were conducted. In these trials six soil types of different properties were used. The total number of pots was 160 (40 variants in 4 replicates). Soils were artificially contaminated by Cd and the selected variants also by Zn. The contents of Cd and Zn in soil extractants and seedlings were compared with the contents of these elements in corn mature plants (roots and stems) by means of regression analysis. For cadmium, the best results as to the prediction of its content in mature plants were obtained with NaNO₃, whereas for zinc the best results were given by the seedlings.     

Nitrogen-15 in NO3- characterises differently reactive soil organic N pools

Intercropping with legumes is known to increase the plant-available nitrogen (N) in soil, but can also increase leaching of NO3- to the groundwater. To minimise NO3- leaching risks, knowledge of the N-release processes is essential, including an estimate of the contribution of legumes to total NO3- concentrations in soil. Our objectives were to answer the questions: (1) whether the presence of legume roots increases N mineralisation, and (2) whether the proportion of legume-derived N in NO3- could be calculated with the help of natural abundance 15N in NO3-. We sampled soil monoliths of a Medicago x varia Martyn monoculture in August 2004 and set up three treatments: 'disturbance' (sieved to <2 mm), 'disturbance-roots' (sieved to <2 mm and visible roots removed), and 'control' (left untreated). During an incubation period of 70 days, an N-free nutrient solution was leached through the samples weekly. In the leachates we measured total N, total organic carbon, NO3-, and NH4+ concentrations. Six of the 13 sampling dates were chosen for N isotope analysis in NO3-. Nitrate was separated as AgNO3. During the incubation, 3 to 6% of the initial total mass of total N (192 to 274 mg N) in soil was mineralised. Nitrogen mineralisation followed zero-order kinetics independent of treatments. Mineralisation rates decreased in the order control (day 70: 3.7 microg NO3-N (mg Ninitial)-1)>disturbance-roots (2.6 microg NO3-N (mg Ninitial)-1)>disturbance (1.9 microg NO3-N (mg Ninitial)-1), indicating that mineralisation of legume roots did not play a major role in N mineralisation. The delta15N values jumped from ca. 3 per thousand to ca. 8 per thousand after 2 weeks of incubation, which we attributed to the contribution of two N pools. An exponential two-pool model could not be fitted to the data. Legume-derived soil organic matter, SOM (pool 1), was mineralised at the same rate as SOM accumulated before establishment of the legumes (pool 2). Fresh legume roots did not contribute significantly to N mineralisation.     

土壤电化学性能对铀、锶、铯分配系数的影响及机理探讨

通过静态吸附实验研究了土壤pH值、正电荷AEC值、永久负电荷CECp值等电化学性能对核素铀、锶、铯分配系数的影响,进一步结合XRD物相分析结果,对土壤滞留核素的机理进行了探讨.研究结果表明:所研究的两种土质类型中,铀的分配系数(U-Kd值)均随溶液初始pH值的减小、AEC值的增大而增大;铯、锶的分配系数与土壤的CECp值、蒙脱石和伊利石总含量呈正相关关系;Cs 、Sr2 离子势及其相应水合离子半径的差异造成土壤中铯的分配系数显著大于锶的分配系数.