南极乔治王岛环境质量现状调查   总被引：4，自引：0，他引：4       下载免费PDF全文

蒲家彬  李宗品  邵秘华  尚龙生 《极地研究》1995,7(2):54-61

本文以１９９２／１９９３年度中国第九次南极考察期间对南极乔治王岛的表土、地衣、苔藓等样品的分析资料为基础，研究探讨了８种无机重金属元素、５种有机污染物的浓度水平。其结果表明，重金属在三种环境样品中的含量分布存在着明显的差异；地衣、苔藓两种植物呈现对不同重金属元素的不同富集能力；∑６６６、∑ＤＤＴ和ＰＣＢｓ及油的沾污亦很明显。本文还对污染物质的来源、南极环境样品历次调查分析的结果以及世界部分地区的背景水平进行了讨论和比较  相似文献   

A comparison of the early diagenetic environment in intertidal sands and muds of the Manukau Harbour,New Zealand     

R. B. Williamson  T. M. Hume  J. Mol-Krijnen 《Environmental Geology》1994,24(4):254-266

The early diagenetic environment of intertidal sandy sediments (sands) and muddy sediments (muds) is described and compared from two cores taken from an unpolluted part of the Manukau Harbour, New Zealand. Extraction techniques characterized the form of the trace elements (Fe, Mn, S, C, Pb, Zn, Cu) at different depths in the sediment. Dissolved forms of Fe, Mn, and S were measured in interstitial water. Nonresidual metal concentrations, humic acid, FeS, and FeS₂ are an order of magnitude higher in the muds than in the sands because of dilution by unreactive sand particles. Muds contain a larger proportion of metals in the mobile fractions; exchangeable (Mn), carbonate (Mn, Fe, Zn), and easily-reducible oxide (Fe, Mn, Zn, Pb). This is due to greater surface area (for Mn adsorption); the favorable conditions for MnCO₃, FeCO₃, and FeS precipitation; and higher concentrations of easily reducible iron oxide and humic acid. Therefore, compared to the sands, muds are more important as reservoirs for toxic metals, both in terms of quantity and availability. At either site there was very little difference between the forms of Zn, Pb or Cu identified by sequential extraction as sediments changed from oxic to anoxic conditions. One reason for this is that the amounts and proportions of some of the important components that bind metals, viz., amorphous iron hydrous oxides, humic acids, and FeS₂, do not change much. Other components that do change with redox conditions, for example, manganese phases and FeS, are only minor components of the sediment. Redox conditions, then, have relatively little effect on trace-metal partitioning in the sediment matrix of these unpolluted sediments.  相似文献   

Magnetic properties as indicators of heavy metals pollution in urban topsoils: a case study from the city of Luoyang, China   总被引：8，自引：0，他引：8  

S. G. Lu  S. Q. Bai  Q. F. Xue 《Geophysical Journal International》2007,171(2):568-580

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Partitioning,bioavailability and origin of heavy metals from the Nador Lagoon sediments (Morocco) as a basis for their management   总被引：2，自引：0，他引：2  

I. González  E. Águila  E. Galán 《Environmental Geology》2007,52(8):1581-1593

Nador Lagoon sediments show low trace element concentrations, and, in relation to the lagoon geochemical baseline, only some anomalies for As, Cd, Cu and Pb in the NW of the lagoon deserve to be outstanding. The distribution of major, minor and trace elements in the lagoon allows a breakdown in four zones. Between “Beni Ensar” and “Atelouane” (zone A), a quite confined zone rich in organic matter and S, the most important trace-element anomalies (As, Cd, Co, Cu, Mn, Pb, Zn) were found, mainly around industry and old mining activities. In the surrounding of the city of Nador (zone B), the anomalies correspond to Mn, Cu and Zn. The coastal barrier and Kebdana channel (zone C) show moderately concentrations of Cd, Cr and Ni at specific sites. The less polluted area is the SE of the lagoon (zone D), with no outstanding anomaly. In lagoon sediments, metal bioavailability is very low. The metal partitioning patterns show that Cu, Pb and Zn present a low availability because they are bounded to the residual, non-mobile phases of the sediments. Only in some sites, the fraction was associated with organic matter, which could be liberated easily. Arsenic is concentrated in both the residual phases and the organic matter, the latter being more available. Cadmium is mainly concentrated in some samples in the interchangeable fraction, which could be considered as a potentially toxic element because it is easily released. Concerning the origin of these trace elements, those found in zone A correspond mostly to a natural source by weathering of mount Gourougou volcanic rocks (As, Co, Cu, Pb and Zn), and to an anthropogenic origin (Cd) owing to the presence of industry and old mines. In zone B, contributions of Cu and Zn enter the lagoon through soil weathering and river-borne, and as anthropogenic pollution from urban wastes. In zone C the most important pollutant is Cd deduced to be of anthropogenic origin from the close industry and intensive agriculture area. In spite of the intense socio-economic activities developed in the Nador Lagoon (agriculture, industry, fishing, tourism) trace element concentrations in the sediments are low and with scarce bioavailability. Only the NW sector is relativity polluted because of geogenic features.  相似文献   

Paleolimnological assessment of human impacts on an urban South African lake     

F. García-Rodríguez  C. R. Anderson  J. B. Adams 《Journal of Paleolimnology》2007,38(3):297-308

North End Lake is a polluted and eutrophic freshwater system located in Port Elizabeth, South Africa. Since the lake is expected to be used for recreational/tourist purposes by 2010, a rehabilitation program will have to be designed. For this reason, we retrieved a sediment core from the central region of the lake to decipher the effect of historical human impacts on the water body. Pre-disturbance paleolimnological inferences indicate that the lake was likely mesotrophic. After ∼1831, when sheep farming activities were undertaken in the catchment, increases in trophic state and changes in sediment composition were observed. After ∼1937, increases in trace metal levels, organic matter, spheroidal carbonaceous particles (SCP) and changes in sediment composition were recorded. The system became eutrophic as indicated by the dominance of the diatom Actinocyclus normanii, a cosmopolitan species often observed in systems where water quality has been dramatically degraded. The conditions worsened after 1986 because of the construction of a storm-water retention system, which intentionally channeled storm-water runoff into the lake. Because of this, extremely high values of fecal coliforms (i.e. 2 × 10⁶ every 100 ml) have been measured in the water column. The paleolimnological information identified the sharp increase in organic content in the uppermost section of the core, and this could be correlated to the operation of the storm-water retention system. Therefore, as an immediate management measure, we suggest that the storm-water retention system should either no longer be utilized, or the storm-water runoff should be treated before disposal into the lake. In addition, an effective sewage system has to be constructed.  相似文献   

The radio frequency dielectric properties of the stratified UG1–UG2 geological unit in the Bushveld Complex     

Marc Rütschlin  Johannes H. Cloete  Iain M. Mason  Keith D. Palmer   《Journal of Applied Geophysics》2007,62(4):354-360

A new measurement technique enables the complex dielectric properties of the geological strata comprising the UG1–UG2 (Upper Group 1–Upper Group 2) unit of the Bushveld Complex in South Africa to be determined with unprecedented detail at radio frequencies (RF). Results of non-destructive laboratory measurements of representative diamond drill core samples from the UG1–UG2 unit are presented at 25 MHz. These data establish that the UG1 and UG2 chromitite layers are embedded in rock strata (norite, pyroxenite and anorthosite) which are translucent in the HF spectral band, whereas the chromitite layers themselves exhibit significant velocity contrast, making them good radar reflectors. The data presented here is useful for calibration of the radar system, and for predicting the range and resolution performance of borehole radars operating in both the hanging and footwalls of the economically important platiniferous UG2 reef.  相似文献   

Use of variograms for field magnetometry analysis in Upper Silesia Industrial Region     

J. Zawadzki  P. Fabijańczyk 《Studia Geophysica et Geodaetica》2007,51(4):535-550

Measurements of topsoil magnetic susceptibility are often used for quick assessment of soil contamination of anthropogenic origin, with heavy metals or other pollutants. However, because of complicated correlations between low-field magnetic susceptibility (shortened to magnetic susceptibility) of topsoil and soil pollution, the outcome of a field magnetometry survey can not be related directly to soil pollution. For each case study, the results should be interpreted on their own taking into account not only the type of pollution but also pedogenic, biogenic and environmental factors. In practice, it is very difficult to measure and consider all these factors. Here we illustrate the merit of geostatistical methods, which are focused on the spatial variability of a phenomenon, in the interpretation of soil magnetometry results. This article presents the analysis of spatial variability of top soil layers magnetic susceptibility-within the Upper Silesia Industrial Region (USIR)-using semivariance analysis. It also explains how to adjust the sampling density of field magnetometry measurements to spatial variability of the soil pollution as well as to the spatial scale of the investigated area. For this purpose, the values of magnetic susceptibility have been measured by using various sampling densities at areas of different size located within USIR. This enabled to determine the main scales of magnetic susceptibility spatial variability of soils within USIR using semivariance. A few distinct scales of variability were found from the site scale to a more regional scale. Variability ranges of 30 km, 12 km, and 5 km refer to the large regional scale, whereas smaller ranges of few hundreds down to a few tens of meters, can be attributed to the local (site) scale. In addition, the precision of the measuring campaigns, performed within USIR with different sampling densities, was compared through the analysis of the spatial variability of the soil magnetic susceptibility signal by using ordinary kriging. jarek97@yahoo.com, piotr.fabijanczyk@is.pw.edu.pl  相似文献   

210Pb and 137Cs dating methods in lakes: A retrospective study   总被引：1，自引：0，他引：1  

Gaboury Benoit  Tim F. Rozan 《Journal of Paleolimnology》2001,25(4):455-465

²¹⁰Pb has been used for more than two decades to provide the geochronology of annually deposited sediments and to construct pollution histories. Evidence from some lakes suggests that this radionuclide may be adequately mobile to compromise dating reliability. This study provides one test of that possibility by comparing recent measurements of ²¹⁰Pb and trace metals to ones carried out more than 20 yrs in the past. ¹³⁷Cs dating is used to confirm sediment accumulation rates in the recent cores. In the three Connecticut, USA, lakes studied, sediment accumulation rates changed abruptly to higher values between 40-50 yrs ago (increasing by factors of 2.2, 2.9, and 3.0). In all three lakes, rates calculated from ²¹⁰Pb distributions both above and below this horizon agreed, within measurement uncertainty, in recent and older cores. Furthermore, when the older data were corrected for 20 yrs of burial, the changes in slope in ²¹⁰Pb distributions occurred at the same depth in each pair of cores. The depth of sharp peaks in concentrations of trace metals also matched. In general, this evidence supports the idea that sediments in these lakes have simply been buried, without significant diagenetic remobilization of ²¹⁰Pb and trace metals . Nevertheless, some important differences were also observed. For two of the three lakes, there was a significant difference in average sediment accumulation rate during the past 33 yrs as calculated from ¹³⁷Cs and ²¹⁰Pb in the recent cores. Most potential causes for this difference can be ruled out, and it appears that one of the two nuclides is remobilized compared to the other. There were also significant differences in the total inventories of both ²¹⁰Pb and trace metals (both up to 2 ×) between recent and older cores in some cases. This may be due to dissimilar sediment focusing, since it is not known for certain whether the new cores were collected at exactly the same sites as in the past.  相似文献   

黑矿型矿床成矿物质来源：日本上向黑矿铼—锇和氦同位素证据   总被引：5，自引：1，他引：5  

侯增谦  杜安道等 《地质学报》2001,75(1):97-105

上向黑矿（Uwamuki Kuroko)是日本最典型的黑矿型矿床，它形成于日本岛弧中新世矢折岛弧裂谷环境，产于双峰式岩石组合的长英质火山岩系中。矿床由下部筒状硅矿带和上部块状黑矿带构成，后者显示典型的上黑（黑矿）下黄（黄矿）金属分带。为探索研究长期争议的成矿物质来源，系统测定了矿石和主岩的Os,He同位素组成。含矿流纹岩系的R／RA值介于0．93－1．14间，证实该岩浆可能主要来源于陆壳重熔。上向黑矿的上部块状黑矿矿石具较高的^187Os/^188Os值（2．246－7．608），反映矿石Os主体来源于壳源沉积物或矿区基底岩系；下部脉状－网脉状硅矿、块状黄矿和少量黑矿则具低^187Os/^188Os值（0．423－0．793），证实矿石Os具两源性，估计幔源物质贡献约57％－89％，壳源物质贡献约11％－43％。此外，在上部块状黑矿带内部，矿石 ^187Os/^188O显示清楚的垂向韵律性变化，揭示了成矿流体及成矿物质的周期性混合，据此，本文提出了一个新的两阶段成矿模式。  相似文献   

去除废水中重金属的低成本吸附剂:生物质和地质材料的环境利用   总被引：27，自引：0，他引：27  

王焰新 《地学前缘》2001,8(2):301-307

经济、有效、易获得的生物质和地质材料 (及二者的废弃物 )可用来取代传统的活性炭或离子交换树脂用于去除废水中的重金属。已经公开发表的低成本吸附剂主要可分为两类 :(1)生物质 (包括林业和农业的废弃物 ) :树皮 /富含丹宁酸的物质 ,木质素 ,几丁质 /甲壳质 ,死的生物体 ,苔藓 ,海草 /海藻 /褐藻酸 ,废弃的茶叶 ,稻壳 ,羊毛 ,棉花等 ;(2 )地质材料 (包括矿物利用后的工业废弃物 ) :沸石 ,粘土 ,泥炭 ,有铁氧化物包壳的砂 ,粉煤灰等。其中 ,对于重金属具有强吸附能力的吸附剂有甲壳质、沸石和木质素 ,例如 ,它们对一些重金属的最大吸附能力分别为 :甲壳质对Cd ,Hg ,Pb分别为 5 5 8,112 3 ,796mg/g ,沸石对Pb为 15 5 4mg/g ,木质素对Pb为 15 87mg/g。地质材料的环境利用值得引起地学界和环境工程界更广泛的重视。基于地质材料和水岩相互作用机理的环境污染控制技术有望成为 2 1世纪重要的环保替代技术。由于缺少连续的可比性强的成本信息 ,要比较不同的生物质和地质材料的成本和吸附性能仍较困难。尽管已对低成本吸附剂领域进行了很多研究 ,但要更好地了解低成本吸附剂的作用机理及其实用性 ,仍需要做大量的室内和现场工作。  相似文献