Lead sorption onto thermally treated soil samples from Irbid

Open burning of waste at dumpsites sites may alter many physical and chemical properties of underlining soil layers including its ability to retard the migration of potential contaminants, such as lead, through the vadose zone. In this study, lead sorption onto soil samples from Irbid that were subjected to high temperatures has been investigated. These samples were collected from ground surface and heated to temperatures of 25, 70, 100, 200, 225, 250, 275, 300, 400, and 550°C. Based on these temperatures the soil was divided into ten different groups. Each group was first characterized by conducting a set of experiments to estimate the Atterberg limits (liquid limit, plastic limit, and plasticity index), the organic carbon content, and a set of batch experiments to study lead adsorption. Results indicate that the LL, PL, total organic carbon are slightly affected by high temperatures less than 200°C, show an abrupt change between temperature from 200 and 300°C, and then slight change above 300°C. Sorption of lead onto heated samples, however, was not significantly changed. This may be explained by the fact that adsorption of heavy metals mainly occurs onto the soil mineral parts which are slightly affected by the temperature range used in this study.     

Partitioning of heavy metals on soil samples from column tests

In this study, column tests were used to determine the retention capability of three types of estuarine alluvia collected adjacent to landfill sites in South Wales. Selective sequential extraction (SSE) was used to study the retention mechanisms of heavy metals in the soil columns obtained from leaching experiments. Acid digestion was later used to check the validity of the SSE results. Breakthrough curves show good retention of heavy metal ions (Pb, Cu, and Zn) by all soils, where almost 99% of heavy metals were retained with the C_e/C_o values in the order of 10⁻³. The retention strength of these soils was observed to be constant up to five pore volumes (PV). This corresponds with the pH of the effluents and pore water of soil slices, which also show good buffering capacity against very acidic leachate up to 5PV. The heavy metal extraction profiles from SSE show very similar trends with the retention profiles from the leaching experiments, where heavy metals were retained mainly at the top part where the leachate entered the column. SSE indicates qualitatively that heavy metals precipitated with carbonates and amorphous materials (oxides/hydroxides) are higher than heavy metal retention via exchangeable mechanisms. The mass balance calculation gives range of deviation of 1–16% of the total soil extraction. The distribution of the heavy metals with various soil constituents are ranked in the following order: Carbonates>Amorphous oxides hydroxides>Organic matter>Exchangeable phases.     

Numeric examination of multivariate soil samples

Numerical methods for the examination of multivariate soil samples are presented in geometric terms. Techniques of coordinate representation by principal components, by nonmetric scaling, and by a new method are discussed, as are techniques for agglomerative hierarchic cluster analysis. These are illustrated by two sets of previously published data.     

Assessment of bacterial diversity associated with crude oil-contaminated soil samples from Assam

In this study, we are reporting bacterial diversity in crude oil-contaminated soil of Assam, India. Integration of physiological community profiling, culture-dependent and culture-independent (metagenome) approaches, was employed to obtain a complete picture of the total bacterial diversity. Samples collected from 10 sites contaminated with crude oil ranging from 0.22 to 89.36% were analysed, and altogether 160 culturable bacteria were isolated (117 Gram-positive and 43 Gram-negative bacteria). Molecular identification showed the predominance of genera Lysinibacillus, Alcaligenes, Bacillus, Clostridium, Enterobacter and Pseudomonas. Conversely, denaturing gradient gel electrophoresis (DGGE) profiles of 16S rDNA phylotypes showed the predominance of Sphingomonas, Ralstonia, Sphingobium, Massilia, Acinetobacter and Pseudomonas. Both culture-dependent and culture-independent approaches resulted in 11 genera of which Bacillus and Pseudomonas were the key inhabitants creating most favourable bacterial milieu in the presence of crude oil contaminants. Metabolic fingerprints data depicted in PCA plot demonstrated that sites CTF-D-1 and Core-10 were most diverged. It was further confirmed that variations of bacterial species dominance in different sites were due to origin of hydrocarbon contamination. We here claim that the present findings is a first-hand report on combined physiological community profiling, culture-based and culture-independent approaches in assessing total bacterial diversity in crude oil-contaminated soil of Assam.     

油气化探土壤样品解吸气技术实验研究

油气地球化学勘探中常用的顶空轻烃和物理吸附烃属于吸附态的烃类,两者在处理土壤样品时没有粉碎,使得吸附烃没有完全解吸. 油气化探土壤样品解吸气技术就是利用自行研制的油气化探原位土壤样品保存与解吸装置,通过实验选择加饱和盐水或纯净水,改变样品量、样品解吸时间、负压条件,从而确定解吸气提取的最佳实验条件,建立油气化探土壤样品解吸气提取的方法. 运用重复性对该方法进行评价,并选择富安油田试验区的一条已知地质剖面开展土壤中解吸烃指标的应用,研究结果表明,解吸气技术在油气藏上方具有较好的化探异常响应.     

隐伏区土壤化探样品中元素活动态异常值的统计识别

建立了隐伏区土壤地球化学测量中元素活动态值异常下限（T）的统计计算方法,定义了点对比值（Ci=xi/T）,制定了Ci〉1为异常值的统计识别模式。应用新建立的方法,在森林及土壤覆盖景观的金厂矿区进行了实验和应用。由已知区的实验结果表明,土壤中活动态金异常值分布与已知金矿带完全对应,并且在远景区所圈定的金异常区与地质认识相符,部份异常已经钻探工程验证。     

Reaction of soil enzymes and spring barley to copper chloride and copper sulphate

Study was carried out to compare the effect of the degree of contamination of soil with copper on the soil enzyme activity, depending on the type of chemical compound with which a metal reaches the soil and on the method of soil use. An effect of increasing doses of copper on growth and the development of spring barley has been studied. The study was carried out as a pot experiment on two types of soil: loamy sand and light loam. Copper was introduced to soil as copper(II) sulphate(VI) and copper(II) chloride at four doses: 150, 300, 450 and 600 mg Cu²⁺ kg^?1 d.m. of soil. Soil without copper was used as a control sample. The experiment showed that contamination of soil with copper applied as CuCl₂ and CuSO₄·5H₂O upset the homeostasis of soil. Dehydrogenases and urease were the most sensitive to contamination of soil with Cu²⁺, both as copper(II) chloride and as copper(II) sulphate(VI), and acid phosphatase and alkaline phosphatase were the least sensitive. Greater changes in enzymatic activity were observed in loamy sand than in light loam. The differences in the impact of copper(II) sulphate(VI) and copper(II) chloride on the soil microbiome were relatively small, because mean ED₅₀ for copper(II) chloride was 341 mg Cu²⁺ kg^?1 d.m. of soil, and for copper(II) sulphate(VI) it was 364 mg Cu²⁺ kg^?1 d.m. of soil. This inhibitory effect of copper persisted throughout the period of the experiment. The sensitivity of spring barley to copper compounds was lower than the enzymes under study.     

气泡混合轻质土试样制备研究

由于气泡消泡的缘故,室内制备和现场浇筑气泡混合轻质土时存在塌陷问题。为分析和解决该问题,以砂土为原料土,开展了不同温差、湿度和掺砂与否条件下3种密度气泡混合轻质土的制备试验,并测定了各试样的高度和强度,基于热力学理论分析了3种因素对试样制备和强度的影响规律。试验结果表明,试样制备时温度与养护温度之间的温差是影响气泡混合轻质土胀缩性的决定性因素,轻质土中的气泡含量越高,受温差影响越大,通过控制温差即可解决塌陷问题;湿度和掺砂与否对气泡混合轻质土的试样制备影响不明显,但是湿度高会延长试样脱模时间以及影响试样的完整性;温差和温度共同影响气泡混合轻质土的早期强度,其中温差主要影响试样密实度,温度主要影响水泥水化反应速率。试验结果可为气泡混合轻质土制备和施工时间点选择提供借鉴。     

岩土样本力学参数的模糊统计特征研究

岩土工程参数中的各种信息都存在模糊性。通过对岩土样本力学参数试验值的研究,提出当分析样本统计特征时,应该充分考虑模糊不确定性因素对参数特征值的影响。在确定的参数隶属函数基础上,推导了岩土样本力学参数模糊统计特征值的计算公式,并证明了公式的合理性。应用实例表明,由于文中提出的计算方法考虑了参数模糊性的影响,其计算结果比按常规统计方法得到的结果更具合理性。在任何情况下,模糊方差和模糊变异系数都比常规统计方法得到的方差和变异系数小。分析结果表明,该方法具有广泛的推广价值。     

Isotopic composition of zinc, copper, and iron in lunar samples

We determined by ICP-MS the concentrations and isotopic ratios of Fe, Cu, and Zn in the Ti-rich lunar basalt 74275, in the lunar orange glass 74220, and in up to 10 lunar soils, namely, 14163, 15231, 64501, 66041, 68841, 69941, 70011, 72501, 75081, and 76501. Two analyses of zinc in lunar basalt 74275 give δ⁶⁶Zn = 0.17‰ and 0.75‰, values within the range of those measured in terrestrial basalts; copper in lunar basalt 74275 has δ⁶⁵Cu  +1.4‰, which is isotopically heavier than values observed in terrestrial basalts. In the orange glass, we measured δ⁵⁶Fe = −0.24‰, δ⁶⁵Cu = −0.42‰, and δ⁶⁶Zn  −3.6‰. These values of δ are more negative than those obtained for 74275 and for typical lunar basalts, but for Cu, comparable to those observed in terrestrial sulfides and meteorites. In lunar soils we found 0.11‰  δ⁵⁶Fe  0.51‰, 2.6‰  δ⁶⁵Cu  4.5‰, and 2.2‰  δ⁶⁶Zn  6.4‰. Insofar as we can generalize from a small sample set, S, Fe, Cu, Zn, and Cd show similar trends in isotopic fractionation on the Moon. Lunar basalts have nearly terrestrial isotopic ratios. Relative to the lunar basalt 74275, the pyroclastic glass 74220 is enriched in the lighter isotopes of Fe, Cu, and Zn, and the soils are enriched in the heavier isotopes of Fe, Cu, and Zn. The patterns in the basalts are likely inherited from the source material; the light-isotope enrichments seen in the orange glass originated during lava fountaining or, less probably, during partial condensation of vapor; and the heavy-isotope enrichments in the lunar soils were likely created by a combination of processes that included micrometeorite vaporization and sputtering. In the orange glass, the light-isotope enrichments (relative to lunar basalts) of Zn are larger than those of Cu. If these enrichments reflect accurately the isotopic composition of the gas, they suggest that Cu is more volatile than Zn in the liquid from which the gas derived. A simple model built on the known flux of micrometeorites to the lunar surface and a published estimate that micrometeorites generate 10 times their own mass of vapor, predicts heavy-isotope enrichments comparable to those observed in soils but only if the regolith gardening rate is set at about one twentieth of the generally accepted value of 1 cm/My. This discrepancy may reflect the difference in the time constants for micrometeorite milling and decimeter-scale gardening, or the importance of sputtering.     

Bayesian soil assessments combining prior with posterior censored samples

The geotechnical engineer is often faced with the problem of how to assess the statistical properties of a soil parameter on the basis of a sample measured in-situ or in the laboratory with the defect that some values have been replaced by interval bounds because the corresponding soil parameter values have turned out to exceed the capacity of the measuring instrument. Given such a censored sample the problem is to estimate the mean value, variance and certain fractiles of the distribution of the soil parameter as it would be measured by an instrument of unrestricted range. In many situations only a small censored sample is given. To estimate the characteristic value defined as a lower fractile value corresponding to a codified probability value, the geotechnical engineer is thus urged to supplement the information from the measurements at the actual location by considering whatever prior knowledge is available about the soil parameter distribution. The present paper shows how a characteristic value by computer calculations can be assessed systematically from the actual sample of censored data supplemented with prior information from a soil parameter data base.     

原子荧光光度法测定土壤样品中砷的不确定度评定

通过原子荧光光度法对土壤样品中砷重复测定6次，计算实验标准差，同时对测试过程系统效应产生的不确定度分量进行评估，从而评定其不确定度。     

Comparison of total and partial extractable copper in anomalous and background peat samples

Nitric-perchloride acid, 0.5 M hydrochloric acid, 0.05 M EDTA and neutral ammonium acetate were investigated as extractants for copper in peat samples. Greatest contrast between anomalous and background samples was found with nitric-perchloric acid (‘total’) digestion. EDTA or dilute hydrochloric acid liberated 13–100% of the total copper whereas ammonium acetate removed a maximum of 8%.     

Potential metal pollution in grass and soil samples around brickworks

42 soil samples, chosen from 4 transects around brickworks in the Göttingen area (W. Germany), were examined for the toxic elements Bi, Tl, Cd, Pb, and Zn, as well as Fe, Mn, and organic carbon. In 44 plant samples (grass) taken from the same sites the trace elements Cd, Pb, and Zn and the matrix elements K, Ca, Mg, and Na, were determined. Around brickworks, which are situated in an unfavorable morphological region, small anomalies could be detected. A comparison with a highly polluted area around a lead-zinc smelter shows the relatively low level of pollution of the Göttingen area. By investigating 3 different sets of clay and bricks, the loss of some volatile heavy metals in the process of converting clay to brick could be estimated; the losses are between 17 and 83 percent. Extrapolating this to the entire German Federal Republic, Cd, Tl, Bi, and Hg are emitted in the 10–30 (tons per year) range, Pb and Zn in the 500–100 t/y range. The contamination of the environment by these metals from brickworks is about equal to that released by the coal as it is burned.     

岩石、土壤样品中210Po测定方法的研究

研究了以铜箔为镀片时,自沉积总α计数法定量测定岩石、土壤样品中210Po的最佳制源环境、同位素的干扰和去除、共存元素的允许量以及适宜的溶(熔)矿方法,同时研究了银、铜两种镀片的区别。试验发现,当盐酸浓度为2.0mol/L,恒温80℃,振荡频率为180次/min、振程20mm时,制源2.0h,210Po自镀回收率在99.6%～100.4%之间,210Po加入量与α净计数率线性相关系数为0.9999。放置衰变法可以消除212Bi和218Po等短半衰期核素对210Po测量产生的影响,Vc存在时其它共存元素不干扰测定。方法配合HNO3HFHClO4溶矿(对复杂试样酸溶后的不溶渣,再进行碱熔),全程回收率为99.5%～100.4%。     

层析法提取土壤样品中活动态铀及其找矿意义

阐述了层析法提取土壤中金属活动态元素的原理、层析法提取土壤活动态铀的测试结果以及该项技术在内蒙古赛汗塔拉地区、桂北沙子江矿床、粤北MHK矿床的试验效果。将层析法与元素活动态方法中的水溶态铀提取法作了比较,结果表明：两者找矿效果基本相同,但层析法的精密度较好。     

Biological copper extraction from melting furnaces dust of Sarcheshmeh copper mine

This paper deals with bacterial leaching of copper dust emanating from furnaces at Sarcheshmeh copper complex. Regarding the considerable amount of acid leachable copper, a sulphuric acid leaching process was performed prior to bacterial leaching. Some shake flask and then bioreactor tests were conducted using a mixed culture of Acidithiobacilli and the effect of significant parameters such as culture medium, pulp density and bacterial inoculation rate were investigated. By increasing the pulp density because of higher toxicity and shear stress much more microorganisms and richer nutrient medium were needed. Favoured conditions that governed the agitated bioreactors caused a remarkable promotion in metal dissolution rate in comparison with shake flask. Copper recovery by bacterial leaching in shaking flasks and chemical leaching after 22 d were 87% and 38%, respectively. At the same condition, the maximum copper recovery in bioreactor was 91% within 6.5 d.     

Effect of aging on bioavailability of copper on the fluvo aquic soil

The bioavailability of copper in contaminated soils has received more attention due to the safety concern of food chain. The bioavailability of metals is determined by its fractions which are affected by the soil properties and its aging time. This paper focused on the aging effect on the bioavailability of copper added to the soil. The garden soil (fluvo aquic soil) was treated with 100 mg/kg and 1000 mg/kg of copper(II) sulfate and incubated for 14, 21, 28, 42, 63, 120, 200, 300 and 400 days in the laboratory respectively. The sequential extraction procedure was used to characterize copper bioavailability in the soil. Meanwhile, the barley was cultured on the same soil incubated and its toxicity was assessed according to the guideline of International Organization for Standardization. The findings show that the exchangeable and carbonate-bound copper decreased with the aging time after addition of copper(II) sulfate to soil. Meanwhile, the percentages of Fe-Mn oxides- and organic-bound copper increased. The residual copper was changed little during the aging course. The copper fractions became stable in soils after 60 days. The kinetic equations showed that the Power function and the Elovich equation were well fitted to the experimental data, and the r² values ranged from 0.840 to 0.982 and 0.741 to 0.975, respectively. The barley test showed that the barley root length was more sensitive to reflect copper toxicity than the shoot biomass, and the exchangeable and carbonate-bound copper were significantly correlated with the barley root length.     

石墨炉原子吸收光谱法测定土壤样品中镉

采用磷酸氢二铵作基体改进剂塞曼扣背景石墨炉原子吸收光谱法测定土壤样品中镉，方法检出限DL=0．012μg／g，精密度RSD在3．55％～7．33％，满足了土壤样品中镉测定的镉质量要求。