Mathematical prediction of lead removal from carbonate-rich illite     

R. S. Li  R. N. Yong  L. Y. Li   《Engineering Geology》2001,60(1-4):159-171

The interaction between heavy metal contaminants and surface forces associated with the reactive surfaces of soil particles was studied with the aim of developing an analytical tool that would permit the prediction of heavy metal and soil sorption–desorption phenomena. The predictive model developed in this study considers the energy of the interaction developed between a lead contaminant and illitic soil. Since these energy calculations include both inner and outer sphere complexes, energy balance requirements can be realistically evaluated with respect to environmental mobility. For a comparison between the calculated values obtained from the predictive model and experimentally obtained measurements, laboratory batch equilibrium tests and electro–kinetic tests were used. These were concerned with the sorption–desorption determination of illitic soil samples with the lead contaminant in the form of a lead nitrate solution. The force balance of lead ions indicates that lead ions in the so-called Stern layer, i.e. the first two layers of a water molecule, are non-removable. Good correlations between calculated and measured values were obtained.  相似文献   

岩溶交代—充填型矿床铅锌品位分维及其地质意义   总被引：1，自引：0，他引：1  

汪劲草  汤静如  彭恩生 《矿产与地质》2001,15(1):11-14

利用分形理论研究了江永岩溶交代－充填型矿床铅锌品位的分形结构特征，结果表明铅，锌品位分布具有自相似性，矿床成因类型与成矿构造类型分别是影响品位分维D值大小的主，次因素，分维D值在一定程度上为解决矿床地质问题提供了某些定量信息。  相似文献   

Lead Contamination Adjacent to Roadways in Trujillo,Venezuela     

Tracy Newsome  Freddy Aranguren  Robert Brinkman 《The Professional geographer》1997,49(3):331-341

This study analyzes the extent and pattern of lead contamination along roadways in Trujillo, Venezuela, using traffic counts and soil samples collected in the field. The normalized mean lead level for frontyard samples along major traffic arteries was 200 μgg ^-1 versus 0 μgg^-1 for backyard samples. Furthermore 55%of the frontyard lead levels were hazardous, versus 7% of the backyard samples. This suggests a strong relationship between traffic and soil lead content. However, a relationship between lead level spatial patterns and traffic volume patterns was not established, suggesting that factors beyond traffic volume, such as slope and erosion, play a significant role in contamination patterns.  相似文献   

图们江口水中Zn,Cd,Pb,Cu的形式分析   总被引：1，自引：0，他引：1  

张首临  李泽林 《海洋科学》1992,16(5):47-50

本文用防吸附物理涂汞电极反问极谱对图们江口、东海及日本海水中Zn,Cd,Pb,Cu进行了形式分析,其不稳定态的平均浓度分别为5.9,0.071,0.039,0.69ug/L(占总量的15～27％),分布较为均匀,证实了痕量金属离子(自由离子及不稳定络离子的均匀分布规律。有机结合态Zn,Cd及Pb(10～30％)和颗粒态Zn,Cu和Cu(15～40％)的较高含量位于长江口、东海及图们江口。  相似文献   

Outokumpu revisited: New mineral deposit model for the mantle peridotite-associated Cu–Co–Zn–Ni–Ag–Au sulphide deposits     

P. Peltonen  A. Kontinen  H. Huhma  U. Kuronen 《Ore Geology Reviews》2008,33(3-4):559-617

The metaturbidites of the Palaeoproterozoic Jormua–Outokumpu thrust belt in eastern Finland enclose m- to km-scale ultramafic massifs that are distributed over an area of more than 5000 km². These bodies, which almost entirely consist of highly depleted mantle peridotites (now metaserpentinites and metaperidotites), are intimately associated with massive to semimassive, polymetallic Cu–Co–Zn–Ni–Ag–Au sulphide deposits that sustained mining in the region between 1913 and 1988. Currently, one deposit (Kylylahti) is proceeding into a definitive feasibility study emphasising the renewed economic interest for Outokumpu-type deposits.The origin of these Outokumpu-type Cu–Co–Zn–Ni–Ag–Au deposits is now re-interpreted to be polygenetic. First, their formation requires deposition of a Cu-rich proto-ore within peridotitic sea floor at  1950 Ma. Close modern analogues to the proto-ore setting include, for example, the Logatchev and Rainbow fields at the Mid-Atlantic Ridge, where venting of high-T–low-pH hydrothermal fluid resulted in accumulations of Cu–Zn–Co–Ag–Au sulphides on serpentinised ultramafic seafloor. Second, the Ni-rich composition of Outokumpu sulphide ores calls for a separate source for nickel: Some 40 Ma after the deposition of the Cu-rich proto-ore – concomitant with the obduction of the ultramafic massifs – disseminated Ni sulphides formed through chemical interaction between obducting peridotite massifs and adjacent black schists. This process was related to listwaenite–birbirite type carbonate–silica alteration at margins of the ultramafic massifs. Due to this alteration, silicate nickel was released from the primary Fe–Mg silicates and redeposited as Ni sulphides in the alteration fringes of the massifs.We propose that syntectonic mixing of these two “end-member” sulphides, i.e., the primary Cu-rich proto-ore and the secondary Ni-sulphide disseminations, resulted in the uncommon metal combination of the Outokumpu-type sulphides. Late tectonic solid-state re-mobilisation, related to the duplexing of the ore by isoclinal folding, upgraded the sulphides into economic deposits.  相似文献   

High-precision Pb isotopic measurements of teeth and environmental samples from Sofia (Bulgaria): insights for regional lead sources and possible pathways to the human body     

George D. Kamenov 《Environmental Geology》2008,55(3):669-680

High-precision Pb isotopic measurements on teeth and possible sources in a given area can provide important insights for the lead (Pb) sources and pathways in the human body. Pb isotopic analyses on soils from the area of Sofia, Bulgaria show that Pb is contributed by three end-members represented by two natural sources and leaded gasoline. Sequential leaching experiments reveal that the alumosilicate fraction of the soils is mainly controlled by natural Pb derived from two mountain massifs bordering the city. Around 1/3 to a half of the Pb in the soil leachates, however, can be explained by contamination from leaded gasoline. Contemporary teeth from Sofia residents show very similar Pb isotopic compositions to the soil leachates, also indicating that around 1/3 to a half of the Pb can be explained by derivation from leaded gasoline. The remarkable isotopic similarities between the teeth and the most labile fractions of the local soils suggest that the lead can be derived from the latter. Pb incorporation in the human body via soil-plant–human or soil–plant–animal–human chains is unlikely due to the fact that no significant farming occurs in the city area. The isotopic compositions of the local soil labile fractions can be used as approximation of the bioaccessible lead for humans. Considering all possible scenarios it appears that soil and/or soil-born dust inhalation and/or ingestion is the most probable pathway for incorporation of local soil lead in the local population. The high-precision Pb isotope data presented in this work indicate that apparently the local soil is what plays major role in the human Pb exposure.  相似文献   

Pb concentrations and isotope ratios of soil O and C horizons in Nord-Trøndelag,central Norway: Anthropogenic or natural sources?     

《Applied Geochemistry》2016

Soil O and C horizon samples (N = 752) were collected at a sample density of 1 site/36 km² in Nord-Trøndelag and parts of Sør-Trøndelag (c. 25,000 km²), and analysed for Pb and three of the four naturally occurring Pb isotopes (²⁰⁶Pb, ²⁰⁷Pb and ²⁰⁸Pb) in a HNO₃/HCl extraction. Soil O and C horizons are decoupled in terms of both Pb concentrations and Pb isotope ratios. In the soil C horizon the Grong-Olden Culmination, a continuous exposure of the Precambrian crystalline basement across the general grain of the Caledonian orogen, is marked by a distinct ²⁰⁶Pb/²⁰⁷Pb isotope ratio anomaly. No clear regional or even local patterns are detected when mapping the Pb isotope ratios in the soil O horizon samples. Variation in the isotope ratios declines significantly from the soil C to the O horizon. On average, Pb concentrations in the O horizon are four times higher and the ²⁰⁶Pb/²⁰⁷Pb isotope ratio is shifted towards a median of 1.15 in comparison to 1.27 in the C horizon. It is demonstrated that natural processes like weathering in combination with plant uptake need to be taken into account in order to distinguish anthropogenic input from natural influences on Pb concentration and the ²⁰⁶Pb/²⁰⁷Pb isotope ratio in the soil O horizon.  相似文献   

Lead sorption onto thermally treated soil samples from Irbid     

Wa’il Y. Abu-El-Sha’r  Assal E. Haddad 《Acta Geotechnica》2007,2(1):65-69

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.  相似文献   

氢化物发生—原子荧光光谱法快速检测水体中的铅     

王莉坤 《物探化探计算技术》2007,(Z1)

发展了测定水体中铅的氢化物发生——原子荧光光谱法,选择了最佳测定条件,铅的线性检测范围为0 ng/mL~100 ng/mL,该方法检出限为0.072 9 ng/mL,加标回收率为94.71%~99.86%。该方法操作简便、快速、检出限低、灵敏度高、结果准确。  相似文献   

Lead isotope variations across terrane boundaries of the Tien Shan and Chinese Altay   总被引：1，自引：0，他引：1  

Massimo Chiaradia  Dmitry Konopelko  Reimar Seltmann  Robert A. Cliff 《Mineralium Deposita》2006,41(5):411-428

The Altaid orogen was formed by aggregation of Paleozoic subduction–accretion complexes and Precambrian basement blocks between the Late Proterozoic and the Early Mesozoic. Because the Altaids are the site of abundant granitic plutonism and host some of the largest gold deposits in the world, understanding their formation has important implications on the comprehension of Phanerozoic crustal growth and metallogeny. In this study, we present the first extensive lead isotope data on magmatic and metasedimentary rocks as well as ore deposits of the southern part of the Altaids, including the Tien Shan (Tianshan) and southern Altay (Altai) orogenic belts. Our results show that each terrane investigated within the Tien Shan and southern Altay is characterized by a distinct Pb isotope signature and that there is a SW–NE Pb isotope gradient suggesting a progressive transition from a continental crust environment in the West (the Kyzylkum and Kokshaal segments of the Southern Tien Shan) to an almost 100% juvenile (MORB-type mantle-derived) crust environment in the East (Altay). The Pb isotope signatures of the studied ore deposits follow closely those of magmatic and metasedimentary rocks of the host terranes, thus supporting the validity of lead isotopes to discriminate terranes. Whereas this apparently suggests that no unique reservoir has been responsible for the huge gold concentration in this region, masking of a preferential Pb-poor Au-bearing reservoir by mixing with Pb-rich crustal reservoirs during the mineralizing events cannot be excluded.  相似文献