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排序方式: 共有212条查询结果,搜索用时 906 毫秒
51.
Michael P. Labare Michael A. Butkus Dawn Riegner Nick Schommer Jason Atkinson 《Environmental Geology》2004,46(6-7):750-754
An investigation to characterize the extent and speciation of lead contamination in water, soil, and surrounding biota was conducted at a small-arms firing and skeet range in West Point, New York. Specifically, lead concentrations were examined in sediment, soil, water, plants, fish and invertebrates. There is an elevated concentration of lead in the soil and sediment up to 11,000 g/g and 340 g/g and also evidence of bioconcentration of the lead by the surrounding biota. Earthworms had up to 90% higher concentrations of lead while tadpoles showed 20% higher concentrations compared with their controls. Lead uptake by indigenous plants gave varying results. Two species bioconcentrated lead 20 and 55 times greater than the control plants. These differences were significant (P <0.05 level) when tested by the students t test. Further studies show that the total leachable lead was highest in the invertebrates and vertebrates but not in the plants. 相似文献
52.
Concentrations of total lead as high as 1,600 g/L were detected in gasoline-contaminated and uncontaminated groundwater at three gasoline-release sites in South Carolina. Total lead concentrations were highest in turbid groundwater samples from gasoline-contaminated and uncontaminated wells, whereas lower turbidity groundwater samples (collected using low-flow methods) had lower total lead concentrations. Dissolved lead concentrations in all wells sampled, however, were less than 15 g total lead/L, the current United States Environmental Protection Agency (US EPA) maximum contaminant level (MCL). Because many total lead concentrations exceeded the MCL, the source of lead to the groundwater system at two of the three sites was investigated using a stable lead isotope ratio approach. Plots of the stable isotope ratios of lead (Pb) in groundwater as 207Pb/206Pb versus 208Pb/206Pb, and 208Pb/204Pb versus 206Pb/204Pb were similar to ratios characteristic of lead-based minerals in local rocks of the southeastern US, and were not similar to the stable lead isotopes ratios characteristic of distant lead ore deposits such as Broken Hill, Australia, used to produce tetraethyl lead in gasoline products prior to its phase-out and ban in the United States. Moreover, the isotopic composition of dissolved lead was equivalent to the isotopic composition of total lead in turbid samples collected from the same well, suggesting that the majority of the lead detected in the groundwater samples was associated with sediment particulates of indigenous aquifer material, rather than lead associated with spilled leaded gasoline. The results of this investigation indicate that (1) lead detected at some gasoline-release sites may be derived from the local aquifer material, rather than the gasoline release, and consequently may affect site-specific remediation goals; (2) non-low flow groundwater sampling methods, such as a disposable bailer, may result in turbid groundwater samples and high total lead concentrations, and; (3) stable lead isotopes can be used to clarify the source of lead detected above permissible levels in gasoline-contaminated groundwater systems. 相似文献
53.
54.
广东大宝山南部铅-锌多金属矿床地质特征及找矿方向 总被引:2,自引:0,他引:2
大宝山南部铅-锌矿床赋存于大宝山向斜内的中泥盆统东岗岭组下亚组碳酸盐岩地层中,矿床的形成与地层、构造、岩浆活动有关,通过对该矿床成矿特征及控矿因素的分析,对比矿区外围凉桥—新江、官坪—大镇两个有利成矿远景区的成矿地质条件,研究认为,这两个远景区的成矿地质条件与大宝山南部铅-锌金属矿床基本类似,在矿区外围多个矿化集中区中,最具找矿潜力。 相似文献
55.
辽宁省铅锌矿床,根据其形成背景及物质来源可划分出岩浆热液型、矽卡岩型、陆相次火山热液型、变质海相火山热液型、变质同生沉积型、同生沉积-变质热液再造型、沉积-变质-岩浆热液叠加改造型、盆地热卤水型等8种类型。矿床特征显示出铅锌矿床的形成大多明显地受到了太古代绿岩带及早元古代以来碳酸盐岩地层的控制;在成因上多与优地槽环境下的海底火山活动、地壳深部的热环流作用及活化地台上的岩浆活动有关。铅锌矿床的成矿作用受到了太古代—早元古代地槽形成到回返、中元古代初期地台形成到坳拉谷产生及中生代地台活化三个大地构造发展阶段的影响,同时早古生代中期吉黑地槽系的强烈活动也对地台北缘凡河凹陷内的铅锌矿床的形成起到了明显的控制作用。矿床成因模式受不同大地构造发展阶段的影响而具有明显的演化规律,由太古代末期的变质海相火山热液矿床,早元古代变质同生沉积矿床、变质热液再造矿床,到早古生代中期的盆地热卤水型矿床,最终演化成中生代的岩浆成因型(热液型、矽卡岩型、陆相次火山热液型)矿床及叠生矿床。 相似文献
56.
The Jordanian chabazite-phillipsite tuff and faujasite-phillipsite tuff have suitable mineralogical and technical properties that enable them to be used for ion-exchange processes. These include suitable grain size and total cation exchange capacity, acceptable zeolite content, good attrition resistance and high packed-bed density. The chabazite-phillipsite tuff (ZE1 and ZE2) has an excellent efficiency to remove Pb and an acceptable efficiency to remove Fe, Cu, Zn and Ni from effluent wastewater of a battery factory and other industries. The faujasite-phillipsite tuff (ZE3) is 6.97 times more efficient than the ZE1 and ZE2. A bed of ZE3 (1,000 kg) loaded in a 1.17-m3 column is capable of cleaning about 2,456 m3 of the effluent from the factory at a cost of US $200/ton. The wastewater is contaminated with 20 ppm Pb in the presence of competing ions including Ca (210 ppm), Na (1,950 ppm) and Fe (169 ppm). This quantity of wastewater is equivalent to 120 working days of effluent discharge from the factory at a flow rate of 20 m3/day. 相似文献
57.
Clausthalite in coal 总被引:2,自引:0,他引:2
A lead selenide mineral, tentatively identified as clausthalite (PbSe) based on optical microscopy, scanning electron microscopy with energy-dispersive X-ray (EDAX), electron microprobe, and scanning proton microprobe (SPM), has been described in a number of coals. While clausthalite has been mentioned as a possible source of Se in coal, it is present in such small quantities and sizes, that the mineral identification has not been absolutely confirmed. The mineral specimens examined in this study would contribute, not only to the Pb and Se concentrations in the coal, but also, in at least one case, to Hg concentrations. 相似文献
58.
辽宁省岫岩县王家堡子铅锌多金属矿位于青城子-许屯铅锌矿带上,通过大功率激电测量查明工作区激电异常特征,综合地质、化探信息,笔者认为矿区侵入岩区带状极化率异常是铅锌矿的找矿标志,沉积岩中石墨矿化引起区域性高极化,根据激电剖面异常特征有利于区分矿与非矿。 相似文献
59.
60.
Daniel G. Strawn Patrick Hickey Andrew Knudsen Leslie Baker 《Environmental Geology》2007,52(1):109-122
To remediate Pb contaminated soils it is proposed that phosphorus can be amended to the soils to transform the Pb into poorly
soluble Pb-phosphate mineral phases. However, remediation strategies must account for variable Pb speciation and site-specific
factors. In this study soil mineralogy and Pb speciation in soils from P-amended field trials at sites within the Coeur d’Alene
River Basin in Idaho, USA were investigated. The soils are contaminated from mining activities and are enriched with Fe and
Mn. Selective extraction of the soils indicated that the Fe oxides are poorly crystalline. XRD of the soil clay size fractions
identified quartz, muscovite, kaolinite, siderite, lepidocrocite, and chlorite minerals. Amendment with P fertilizer dissolved
the siderite. No Pb–phosphate minerals were detected by XRD. Electron microprobe analysis showed direct correlations between
Pb, Fe, and Mn in the unamended soils, and negative correlations between Pb and Si. Lead and Mn were strongly correlated.
In the amended soils Fe and P were strongly correlated. Results indicate that the Pb is associated with poorly crystalline
Fe and Mn oxides, and that added P is primarily associated with Fe oxide phases. Comparisons of pore water Pb concentrations
with chloropyromorphite and plumbogummite solubility suggest that in the phosphate-amended soils the pore waters are undersaturated
in these phases, whereas several of the control soil pore waters were oversaturated, indicating the added phosphate suppressed
the Pb solubility. Results from this research provide insight into the geochemistry occurring in the P-remediated soils that
will help in making management and remediation decisions. 相似文献