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1.
Dated sediment cores from four remote Canadian Shield headwater lakes, where atmospheric deposition has been the only input of anthropogenic Pb, situated along a transect extending 300 km from a nonferrous metal smelter, were analyzed for both lead concentrations and isotopic composition; porewater samples collected at the same sites were analyzed for Pb and other geochemical variables. The depth distributions of stable Pb isotope ratios show the presence of several isotopically distinct Pb types since the preindustrial period. Lead from the smelter emissions had an isotopic signature (e.g., 206Pb/207Pb approximately 0.993) that was clearly distinct from those of Pb in aerosols collected at sites remotefrom point sources in Eastern Canada (e.g., 206Pb/207Pb usually approximately 1.15-1.20) and the United States (e.g., 206Pb/207Pb usually approximately 1.15-1.22), allowing the geographical area impacted by the smelter Pb emissions to be traced. On the basis of the sediment Pb isotopic composition, it is estimated that lead from the smelter accounts for 89%, 88%, and 5-34% of the total inventory of anthropogenic Pb deposited in the sediments of lakes located 10, 25, and 150 km from the smelter, respectively; but lead from this point source was not detected in sediments of a fourth lake that is 300 km from the smelter. We also estimate that the amount of smelter-derived Pb deposited within a distance of 150 km is equivalent to 5-10% of the amount released by leaded gasoline combustion in all of Canada. Sharp decreases in the recent Pb fluxes to lake sediments indicate that the measures taken to mitigate metal emissions from the smelter were effective.  相似文献   

2.
The lead content of a representative assortment of foodstuffs and drinking water as well as the lead intake of adults were systematically investigated in 1988 in order to judge the oral lead exposure of the inhabitants of the former German Democratic Republic (GDR). The food-stuffs as well as the drinking water contained normal lead concentrations. Levels exceeding the limits set by the Federal Office of Health and the Decree on Drinking Water were not obtained. The lead intake was 34 g/day in adult men and 25 g/day in adult women according to the results of the basket study, amounting to 11–13% of the PTWI provisional tolerable weekly intake value of lead. An oral lead exposure of the adult population in the former GDR can be excluded.
Zusammenfassung Zur Beurteilung der oralen Bleibelastung der Bevölkerung der ehemaligen DDR wurde der Bleigehalt eines repräsentativen Lebensmittelsortimentes und des Trinkwassers sowie die Bleiaufnahme Erwachsener im Jahre 1988 systematisch untersucht. Die Lebensmittel sowie das Trinkwasser enthielten normale Bleimengen. Überschreitungen der BGA-Richtwerte bzw. des Grenzwertes der Trinkwasserverordnung wurden nicht beobachtet. Die Bleiaufnahme Erwachsener betrug nach den Ergebnissen der Markkorbstudie 34 g/Tag bei den Männern und 25 g/Tag bei den Frauen. Die Ausschöp-fungsrate des PTWI-Wertes der Bleiaufnahme belief sich auf 11 bis 13%. Eine orale Bleibelastung der erwachsenen Bevölkerung der ehemaligen DDR ist auszuschließen.
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3.
By means of atomic absorption spectrophotometry, the authors determined the lead content in vegetable, fruit and soil samples from the environments of a lead-smelting plant. The lead values obtained were some 10- to 100-fold higher than those found normally. The mean lead content in vegetables varied from 2 to 150 p.p.m. in dry matter; that in fruits, from 4 to 35 p.p.m. Lead concentrations ranging from 575 to 2900 p.p.m. were detected in the soil samples. The mean lead content in the atmosphere was between 0.62 and 0.95 mug/m3 (maximum value 12 mug/m3). From these data it was calculated that the total resorption of lead from vegetables, fruits, potatoes and air varied from 0.04 to 0.49 mg/day in the territory under investigation. To protect the population against increased intake of lead, it is recommended to abandon individual and commercial vegetable and fruit growing, especially leaf vegetables. Since the contamination of the soil persists for generations, the authors discuss its replacement by non-contaminated surface soil.  相似文献   

4.
The mineralogy and solubility of air-pollution-control (APC) residues from a secondary lead (Pb) smelter have been studied on samples from the Príbram smelter, Czech Republic, recycling car batteries, with the emphasis on their potential environmental effect. The presence of dominant anglesite (PbSO4) and laurionite (Pb(OH)Cl) was observed in a sintered residue from after-burning chambers (800-1000 degrees C). In contrast, low-temperature Pb-bearing phases, such as KCl x 2PbCl2 and caracolite (Na3Pb2(SO4)3Cl), were detected in the major APC residue from bag-type fabric filters. Metallic elements, zinc (Zn), cadmium (Cd), and tin (Sn) were found homogeneously distributed within this residue. The formation of anglesite, cotunnite (PbCl2), (Zn,Cd)2SnO4, and (Sb,As)2O3 was observed during the sintering of this APC residue at 500 degrees C in a rotary furnace. The 168 h leaching test on filter residue, representing the fraction that may escape the flue gas treatment system, indicated rapid release of Pb and other contaminants. Caracolite and KCl x 2PbCl2 are significantly dissolved, and anglesite and cotunnite form the alteration products, as was confirmed by mineralogical analysis and PHREEQC-2 modeling. The observed Pb-bearing chlorides have significantly higher solubility than anglesite and, following emission from the smelter stack, can readily dissolve, transferring Pb into the environmental milieu (soils, water, inhabited areas).  相似文献   

5.
Natural fluctuations of mercury and lead in Greenland lake sediments   总被引:1,自引:0,他引:1  
Given the current scenario of increasing global temperatures, it is valuable to assess the potential influence of changing climate on pollution distribution and deposition. In this study we use long-term sediment records from three lakes (spanning ca. 1000, 4800, and 8000 years, respectively) from the Greenland west coast to assess recent and long-term variations in mercury (Hg) and lead (Pb), including stable Pb isotopes (206Pb and 207Pb), in terms of pollution and climate influences. The temporal trends in sediment deposited from about the mid-19th century and forward are in general agreement with the history of industrial emissions at lower latitudes. Therefore, in recent sediment a possible influence from changing climate is difficult to assess. However, by using deeper sediment layers we show that changes in Greenland climate caused changes in the lake influx of material from regional aeolian activity, which resulted in large fluctuations in Hg and Pb concentrations and 206Pb/207Pb ratios. The aeolian material is primarily derived from glacio-fluvial material with low Hg and Pb concentrations and a different isotopic composition. For one of the lakes, the fluctuations in Hg concentrations (10 to 70 ng g(-1)) prior to the 19th century are equal to the anthropogenic increase in the uppermost layers, suggesting that when studying recent concentrations and time trends of pollution in relatively low-contaminated areas such as the Arctic, the early natural fluctuations must be considered.  相似文献   

6.
7.
The number and diversity of yeasts on grape berry surfaces are influenced by several factors, such as grape variety, degree of grape maturity at harvest, climatological conditions, geographic location, physical damage of grapes, the intensity of pest management etc. Cvicek is a typical Slovene wine, which has obtained a special protection under the Slovene Wine Law for its geographical origin. This blended red wine is produced from different grape varieties (Vitis vinifera L.), mostly from red grapes of Zametovka and Modra frankinja and from white grapes of Kraljevina. The aim of this study was to evaluate the impact of geographical locations in the Dolenjska vine-growing region and to obtain precise information about the influence of different grape varieties on the composition of yeast community on grape berries. The restriction fragment length polymorphism of PCR-amplified fragments from the rDNA gene cluster (PCR RFLP of rDNA) has been used for the differentiation of yeast species. The standard identification procedure has been performed on representative strains that shared identical RFLP profiles. The number of yeasts and yeast species isolated varied according to different grape varieties, Zametovka, Modra frankinja and Kraljevina (V. vinifera L.) and according to different sampling location. On the surface of grape berries 13 different yeast species have been identified. Saccharomyces cerevisiae has not been found.  相似文献   

8.
High temperature carbon oxidation in primary aluminum smelters results in the release of polycyclic aromatic hydrocarbons (PAH) into the environment. The main source of PAH are the anodes, which are composed of petroleum coke (black carbon, BC) and coal tar pitch. To elucidate the dominant carbonaceous phase controlling the environmental fate of PAH in aluminum smelter residues (coke BC and/or coal tar), the sorptive behavior of PAHs has been determined, using passive samplers and infinitesink desorption methods. Samples directly from the wet scrubber were studied as well as ones from an adjacent 20-year old storage lagoon and roof dust from the smelter. Carbon-normalized distribution coefficients of native PAHs were 2 orders of magnitude higher than expected based on amorphous organic carbon (AOC)/water partitioning, which is in the same order of magnitude as reported literature values for soots and charcoals. Sorption isotherms of laboratory-spiked deuterated phenanthrene showed strong (-100 times stronger than AOC) but nonetheless linear sorption in both fresh and aged aluminum smelter residues. The absence of nonlinear behavior typical for adsorption to BC indicates that PAH sorption in aluminum smelter residues is dominated by absorption into the semi-solid coal tar pitch matrix. Desorption experiments using Tenax showed that fresh smelter residues had a relatively large rapidly desorbing fraction of PAH (35-50%), whereas this fraction was strongly reduced (11-16%) in the lagoon and roof dust material. Weathering of the coal tar residue and/or redistribution of PAH between coal tar and BC phases could explain the reduced availability in aged samples.  相似文献   

9.
10.
天然维生泰丸--枣   总被引:2,自引:0,他引:2  
枣(ZiziphussativaGaertn)为鼠李科枣属,多年生落叶灌木或小乔木,原产我国,已有3000多年栽培历史。我国枣产地除东北严寒地区和西藏外,广泛分布全国各省区,栽培面积约有400万亩,其中主要以河北、山东、河南、山西、陕西5省为集中产区。全国约有700多个品种,其中,生食品种有梨枣、不落酥、马铃枣、冬枣、蛤蟆枣、白枣、酥枣;生食制干兼用品种有板枣、骏枣、金丝小枣、赞皇人枣、壶瓶枣、晋枣、团枣、油枣;制干品种有相枣、无核枣、屯屯枣、木枣、朗枣、婆枣、扁酸核、园铃枣等。枣树对环境适应性强、耐旱、耐盐碱、耐湿、耐瘠薄,结果早,寿命…  相似文献   

11.
Some protocols based on standard methods for the determination of oil in rapeseed by solvent extraction are compared. Test portions of whole seed give unacceptably poor repeatability in results and ground samples should be used for analysis. Moisture content of rapeseed can equally well be determined on ground as on whole seed. The standard methods require modification to take account of these findings.  相似文献   

12.
介绍了国内外条卷机的发展现状;分析了现有条卷机的缺点;介绍了JWF1342型条卷机的性能特点。认为条卷机在未来的市场中还有发展的空间。  相似文献   

13.
斜网成形器与特种纸抄造   总被引:1,自引:1,他引:0  
方尧乐 《中华纸业》2010,31(20):55-60
介绍了国产新型斜网成形器的型式及结构组成,分析了斜网成形器成形过程与特点及特种纸抄造适用性,探讨了斜网成形器生产操作要点。  相似文献   

14.
Vegetables from allotment gardens in the area of Kraków, from the trade (produced at a distance of about 25 km from Kraków), and from farms situated about 100 km from Kraków (control samples) were investigated by atom absorption spectroscopy. In the vegetables from the allotment gardens the levels of the determined elements were on an average several times higher (p less than 0.01) than that of the controls. In a few cases the maximum levels of some elements were near the admissible limit. Furthermore, Pb, Cd, Cu, Zn, and Fe were determined in pigs and cattle (muscle, kidney, liver). The average levels of Pb and Cd gave no reason for objection.  相似文献   

15.
Objectives: To quantify the contribution the tobacco industry has made to foreign direct investment (FDI) in the former Soviet Union (FSU) as an indicator of its political and economic leverage; to explore the impact this has had on production capacity and tobacco control in the region.

Design: Data on industry investment and its impact on cigarette production capacity were collated from industry journals, reports, and websites. Data on total FDI were obtained from the European Bank of Reconstruction and Development.

Results: By the end of 2000, transnational tobacco companies (TTCs) had invested over US$2.7 billion in 10 countries of the FSU. Tobacco money as a proportion of FDI varies from 1% to over 30% in Uzbekistan. Cigarette production capacity in the factories receiving investments tripled from 146 to 416 billion cigarettes per annum and the TTCs' market share has increased from nothing to between 50–100% in the markets in which they invested. Findings suggest that the effectiveness of national tobacco control measures corresponds broadly to the nature of the political and economic transition in each country and the size of industry investment, which is determined in part by the political context. Thus more effective measures tend to be seen in democratic states with smaller or no industry investments while the least effective measures are seen in highly centralised, one party states with high levels of industry investment or those with limited governmental capacity.

Conclusions: The entry of the TTCs at a time of major political and economic change left the FSU particularly vulnerable to industry influence. This influence was enhanced by the industry's significant contribution to FDI, their ability to take over existing state monopolies in all but the largest countries, and the lack of democratic opposition.

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16.
Estimation of the dietary exposure of French consumers to 10 pesticides (omethoate, oxydemeton, phosalon, phosphamidon, triazophos, dicofol (op'+pp'), parathion ethyl, dichlorvos, procymidon and vinchlozolin), three heavy metals (lead, cadmium and arsenic) and three radionuclides (134caesium, 137caesium and 131iodine) from collected duplicate portion in mass catering establishments in 1998/1999 are reported, and compared with those from previous French studies as well as those from other countries. Dietary exposure estimates appear to be reassuring, in that Estimated Daily Intake (EDI) estimates are generally low, representing at maximum only 4% of the Acceptable Daily Intake (ADI) for pesticide residues and 28% of the Provisional Tolerable Weekly Intake (PTWI) for heavy metals. Moreover, none of the three radionuclides has been found in duplicate meals. When comparisons are possible, estimated dietary exposures for heavy metals are lower than those from previous French studies and similar or above those from other countries.  相似文献   

17.
The levels of zinc, copper, lead and cadmium in green tea have been determined by atomic absorption spectrophotometry. With the growth and development of tea shoots, zinc, copper, lead and cadmium concentrations decreased gradually. Some of the lead in green tea was eliminated by washing with water before manufacturing. The range and mean of the zinc, copper, lead and cadmium in 139 green teas were as follows: zinc, 23.4–100.5 and 54.4 μg/g; copper, 4.7–36.5 and 11.4 μ/g; lead, 0.11–1.93 and 0.49 μg; cadmium, 0.013–0.098 and 0.036 μg/g. Significant differences in the contents of copper and lead were observed among the different districts of the country. The green tea produced in some districts near the metropolis areas contained the highest concentration of lead.  相似文献   

18.
Copper, lead and zinc content in canned fruit manufactured in Moldavia in 1979 and 1980 was determined by polarography and atomic-absorption spectrophotometry. The authors developed a method for determining the above trace elements in one sample using an atomic-absorption spectrophotometer. The errors of each method were calculated. It was ascertained that the data obtained by both the methods were identical. Analysis of the data indicates that the content of copper, lead and zinc is within the standards approved by the USSR Ministry of Health. The data obtained in the studies can be used in both toxicological work on setting standards of heavy metals content in canned food and in the tables of the chemical composition of canned food. The methods for copper, lead and zinc determination can be used as the basis for the development of standard procedures for heavy metals.  相似文献   

19.
The aim was to measure concentrations of total mercury, total arsenic, lead and cadmium in common edible fresh fish and shellfish from various areas of the Adriatic Sea. Estimates of intake of these elements were made through seafood consumption by the general population. Samples were either wet digested for mercury and arsenic, or dry ashed for lead and cadmium analysis. Mercury was measured by cold vapour atomic absorption spectrometry (CV AAS) and arsenic, lead and cadmium by electrothermal atomic absorption spectrometry (ET AAS). Quality control procedures of analytical methods, which included analyses of dogfish muscle-certified reference material DORM-2, confirmed the acceptability of methods. The highest mercury and arsenic concentrations were found in hake ( Merluccius merluccius ) and the lowest in mackerel ( Scomber scombrus ). The respective values in hake were 0.373 ±0.075 and 23.3 ±3.6, and in mackerel 0.153 ±0.028 and 1.06 ±0.29 mg kg -1 fresh weight (mean ±SD). Lead and cadmium concentrations were about 10 times higher in shellfish than in analysed fish. The highest lead and cadmium concentrations were found in mussel ( Mytilus galloprovincialis ) and the lowest in hake. Respective lead and cadmium values in mussel were 0.150 ±0.009 and 0.142 ±0.017, and in hake were 0.007 ±0.004 and 0.002 ±0.001 mg kg -1 fresh weight. The concentrations of analysed elements were below acceptable levels for human consumption set by the Croatian Ministry of Health, except for total arsenic. The estimated intake of those trace elements included in this study through seafood consumption by the general population did not exceed the provisional tolerable weekly intake recommended by the Joint FAO/WHO Expert Committee on Food Additives.  相似文献   

20.
Certain volcanoes constitute the world's largest sources of SO2, HCl, and HF emissions and contribute significantly to regional acid deposition. However, the impact of volcanic acid emissions to nearby ecosystems remain poorly documented. In this paper, the spatial pattern of acid dry depositions was monitored within 44 km of Masaya Volcano, Nicaragua, with a network of sulfation plates. Measured SO2 deposition rates were <2-791 mg m(-2) day(-1). The plates also collected the dry deposition of HCI at rates of <1-297 mg m(-2) day(-1). A similar deposition velocity Vd (gas transfer) of 1.6 +/- 0.8 cm/s was calculated for SO2 and HCl above the plate surfaces. Quantities of SO2 and HCI deposited daily within the area surveyed amounted to 1.5 x 10(8) g and 5.7 x 10(7) g, respectively, which correspond to about 10% of the total SO2 and HCl released by the volcano. These depositions may generate an equivalent hydrogen flux ranging from <1 to 30 mg m(-2) day(-1). Our results demonstrate that volcano emissions can dramatically affect acid deposition downwind and in turn cause extreme acid loading of the local ecosystems. This study opens exciting prospects for investigating the sensivity of volcanic ash soils to acid inputs.  相似文献   

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