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1.
Shotyk W. Cheburkin A.K. Appleby P.G. Fankhauser A. Kramers J.D. 《Water, air, and soil pollution》1997,100(3-4):297-310
One metre cores were taken from three peat bogs in the Jura Mountains of Switzerland: Etang de la Gruère (EGr), La Tourbière des Genevez (TGe), and Praz Rodet (PRd). Dried peat samples were analyzed for lead (Pb) using the EMMA XRF and scandium (Sc) using INAA. Enrichment factors (EF) were calculated by normalizing to the background Pb/Sc ratio at EGr. Age dates were obtained using 210Pb (CRS Model) and confirmed using pollen chronostratigraphic markers in replicate cores. The isotopic composition of Pb in selected peat samples from EGr and TGe was determined using TIMS. Two pronounced peaks in Pb EF occur in the uppermost sections of all three bogs: the upper one corresponds to the late 1960's to late 1970's and the lower one to approximately 1900 to 1920. At EGr, sample 2f5 (11 cm, 86 µg/g Pb, EF = 91, and dated at A.D. 1967 ± 2) has an isotopic composition similar to that of leaded gasoline used in Berne in the 1970's. For comparison, the older peak at EGr (sample 2fl 1 at 29 cm, 84 µg/g Pb, EF = 79 and dated at A.D. 1905 ± 6) is significantly different. In contrast to these two samples, the isotopic composition of sample 2fl 5 (41 cm, 30 µg/g Pb, EF = 13 and pre-dating ca. A.D. 1800) approaches the present day "average terrestrial lead" and is likely to be predominately lithogenic. Therefore, the isotopic data show that the Pb introduced to the bog from leaded gasoline has not penetrated to this depth in the profile. A simple mass balance using the measured Pb concentrations and the isotopic compositions shows that vertical migration of gasoline Pb cannot explain the deeper, older peak in Pb EF. A more likely explanation is that the older peak reflects the rates of atmospheric Pb deposition during the first two decades of the 20th century. Taken together, the Pb concentrations, age dates, and isotopic data suggest that these peat profiles have preserved the record of changing rates of atmospheric Pb deposition. In addition, the results indicate that the isotopic composition of Pb deposited on the surface of the bogs gradually shifted away from lithogenic ratios as long ago as the middle of the 19th century, a change which clearly pre-dates the introduction of leaded gasoline. 相似文献
2.
Two hummock cores (separated by 1 m), two hollow cores (separated by 1 m and both within 5 m of the hummock) from ombrotrophic Big Heath, and a single core from Sargent Mountain Pond (12 km north-northeast of the bog), Mt. Desert Island, Acadia National Park, Maine, USA were collected in 1983 and dated using 210Pb and analyzed for a suite of major and trace metals. The hummock cores correspond closely in terms of dating profiles, concentrations of Hg and Pb, and thus trends and values for accumulation rates. The hollow cores agree generally with each other but give more subdued peaks in concentration and lower integrated anthropogenic burdens of Hg and Pb and 50% lower unsupported 210Pb than the hummock cores. Σ210Pbuns. (Bq/cm2), ΣHganth. (ng/cm2), and ΣPbanth. (µg/cm2) for the two hummock cores were 0.744 and 0.773, ≈ 130 and 130 (ng/cm2), and ≈ 159 and 138 (µg/cm2), respectively. The values for Sargent Mountain Pond were 0.411, 269, and 72, respectively. Hummock cores agree closely with the lake sediment core with respect to timing of maximum accumulation rates which occurred in the 1970s; Background atmospheric deposition rates of Hg and Pb to coastal Maine appear to have been about 2.5 to 3 ng/cm2/yr and <0.2 µg/cm2/yr, respectively. Atmospheric deposition of Hg and Pb increased to as much as 20 ng/cm2/yr and 2 µg/cm2/yr, respectively, by the 1970s and has decreased since then. Probably more than 50% of the Hg and Pb are deposited in dry and occult deposition. 相似文献
3.
William Shotyk 《Water, air, and soil pollution》1996,90(3-4):375-405
Peat cores were taken from two contrasting Sphagnum bogs in the Jura Mountains of Switzerland. At Etang de la Gruyere (EGr), 6.5 m of peat has accumulated during the past 10,000 years. In the first 100 cm of this profile there are several distinct peaks in ash content, but the values are well within the range for typical ombrotrophic Sphagnum bogs. There is also considerable variation in the concentrations of major and trace lithogenic metals (Al, Ti, Sc, Ca, Mg, Rb, and Sr), but most of this is simply a reflection of the natural variations in the amount of mineral matter in the peats. The Ca/Mg molar ratios in the peats at EGr are comparable to or lower than the average rainwater composition in this area, showing that this section of the peat core is ombrotrophic (i.e. rainwater-fed). In other words, the inorganic constituents in the surface peats at EGr were supplied exclusively by atmospheric deposition. This peat core, therefore, is suitable for studying the historical record of atmospheric metal deposition. Arsenic, Cu, Pb, Sb, and Zn are all more abundant in surface and near surface peat layers compared to deeper parts of the profile. Enrichment factors (EFs) for the profile were calculated conservatively by normalizing the metal/Sc ratios of individual peat samples to the average of the five lowest metal/Sc ratios in this part of the core (69–84 cm); these are tentatively assumed to represent pre-Industrial background values. The maximum EFs are approximately 5 times for Cu, 15 times for As, and 30 to 50 times for Pb, Sb, and Zn. At La Tourbière des Genevez (TGe), 1.5 m of peat represents 4,800 years of peat formation. At this site, the ash contents are higher and increase progressively with depth to values which are characteristic of minerotrophic fen peats. The concentration profiles of Al, Ti, Sc, Ca, Mg, Rb, Sr show the same general trend. The Ca/Mg molar ratios of these peats are generally twice the rainwater average, showing that this bog is essentially minerotrophic (ie groundwater-fed). Thus, the inorganic cccstituents in these peats were provided by both atmospheric and hydrospheric processes. Despite this, the Cu, Pb, Sb, and Zn concentrations are generally very similar to those at EGr, especially in the uppermost part of the profile, indicating that recent atmospheric inputs also dominate the supply of these metals to this bog. However, the minimum Pb and Sb concentrations in this profile are approximately five times higher than the corresponding values at EGr. The minerotrophic profile at TGT, therefore, could not by itself be used to calculate rates of atmospheric Pb and Sb deposition because it is impossible to distinguish between atmospheric and hydrospheric metal inputs. At TGe, As concentrations increase continuously with depth, reaching concentrations in the deeper, older peats which are more than 50 times higher than the ‘background’ As values at EGr. At this site the natural supply of As by mineral soil water completely masks the recent, elevated inputs contributed by atmospheric deposition. Thus, the peat core from TGe is also unsuitable for studying atmospheric As deposition. 相似文献
4.
Farmer J.G. Mackenzie A.B. Sugden C.L. Edgar P.J. Eades L.J. 《Water, air, and soil pollution》1997,100(3-4):253-270
The concentrations, inventories, fluxes and isotopic composition of Pb in four 210Pb-dated cores from the raised Flanders Moss peat bog are compared with corresponding data for two sediment cores from Loch Lomond, also in central Scotland. Although the inventories and fluxes of Pb revealed by the peat record for the past few hundred years are generally lower, the isotopic records are in good agreement, confirming a prevailing 206Pb/207Pb ratio of 1.17 for anthropogenic ("industrial") Pb in the atmosphere prior to the introduction of leaded petrol in the 1920s. The 206Pb-depleted nature of the latter has resulted in a decline of about -0.04 to -0.05 in the 206Pb/207Pb ratio of deposited Pb for both peat and lake sediments. Despite the time-resolution limitations of the peat record, car exhaust emissions of Pb appear to have contributed 35-50% over the past 20 years, 15-30% over the past 75 years, but no more than 27% overall to the peat Pb burden. The finding that 67-85% of anthropogenic Pb in the peat was apparently deposited post-1900 compared with 51% for the Loch Lomond sediments could be due to geographical variations in atmospheric deposition of Pb, other additional inputs to the sediments, or perhaps to some post-depositional loss of Pb from peat, although the integrity of the 206Pb/207Pb record does argue against any significant vertical mobility of Pb in peat. 相似文献
5.
Historical deposition rates of Hg were determined in 7 ombrotrophic bogs located far from direct sources in Sweden and Norway. The peat bog cores were dated using 210Pb. Based on the dating result 10 to 12 slices from each core were analyzed for Hg. In Southwestern Scandinavia (Rörvik) the deposition rate has increased from about 10 to about 30 μg Hg m?2 yr?1 since the beginning of this century. In Northwestern Norway (Överbygd) the deposition rate has increased from about 10 to about 35 μg Hg m?2 yr?1 since the 1960's. In Southeast Sweden (Aspvreten) the deposition rate decreased since the beginning of this century. There are no significant trends in the historical deposition rates at the two other stations in middle Scandinavia. A comparison between recent Hg deposition rates measured by peat bog analysis, wet precipitation and mosses shows good agreement at all stations except those in Northern Norway were local dry deposition of Hg may be an important source of Hg. 相似文献
6.
From six ombrotrophic mires located far from distinct local sources in Sweden and Norway, a core was sampled in bog hummocks in 1988 and dated by 210Pb. Ten slices from each core were analyzed for Cd, Cu, Pb, and Zn. Based on the datings, the accumulation rates of Cd, Cu, Pb, and Zn have been estimated for the last 150 years. A reasonable agreement exists in the comparison between the recent deposition in the peat bog and nearby bulk deposition measurements. Highest deposition has been measured in southern Norway and the western part of Sweden. Generally, deposition has increased during the last 150 years, except at a station on the east coast of Sweden. In a study in Sweden where heavy metals have been measured in mosses every five years time since 1970, significant decreases in the concentrations of heavy metals have been found. Similar decreases have not been measured in the present study, although both methods are expected to reflect atmospheric deposition. Several studies have indicated that peat bogs are not suitable for measuring the historical evolution of trace metals. However, despite the disagreement, the recent literature suggests that it can be done with reasonable accuracy when performed with samples from hummocks in the peat bog. 相似文献
7.
Two types of bogs were studied in Tomsk oblast—Maloe Zhukovskoe (an eutrophic peat low-moor bog) and Ozernoe (an oligotrophic
peat high-moor bog). The gram-negative forms of Proteobacteria were found to be dominant and amounted to more than 40% of the total population of the microorganisms investigated. In the
peat bogs, the population and diversity of the hydrolytic microbial complex, especially of the number of micromycetes, were
lower than those in the mineral soils. The changes in the quantitative indices of the total microbiological activity of the
bogs were established. The microbial biomass and the intensity of its respiration differed and were also related to the depth
of the sampling. In the Zhukovskoe peat low-moor bog, the maximal biomass of heterotrophic microorganisms (154 μg of C/g of
peat) was found in the aerobic zone at a depth of 0 to 10 cm. In the Ozernoe bog, the maximal biomass was determined in the
zone of anaerobiosis at a depth of 300 cm (1947 μ g of C/g of peat). The molecular-genetic method was used for the determination
of the spectrum of the methanogens. Seven unidentified dominant forms were revealed. The species diversity of the methanogens
was higher in the oligotrophic high-moor bog than in the eutrophic low-moor bog. 相似文献
8.
A. A. Bobrik I. M. Ryzhova O. Yu. Goncharova G. V. Matyshak M. I. Makarov D. A. Walker 《Eurasian Soil Science》2018,51(6):628-636
Statistical analysis of a vast body of data collected during five field seasons (2011–2015) was performed to characterize the biological activity of soils in the northern taiga ecosystems of Western Siberia. Automorphic forest soils, hydromorphic (oligotrophic bog) soils, and semihydromorphic (flat-topped and large peat mounds) soils were characterized. Statistically significant differences of average levels of CO2 emission from the soils were identified at the ecosystem level. The CO2 emission from podzols of automorphic forest ecosystems at the peak of the growing season (205 ± 30 to 410 ± 40 mg CO2/(m2 h)) was significantly higher than the emission from semihydromorphic soils of peat mounds (70 ± 20 to 116 ± 10 mg CO2/(m2 h)). The presence and depth of permafrost was a significant factor that affected ecosystem diversity and biological activity of northern taiga soils. Statistically significant differences in the total, labile, and microbial carbon pools were observed for the studied soils. Labile and microbial carbon pools in the organic layer (10 cm) of forest podzols amounted to 0.19 and 0.66 t/ha, respectively; those in the organic layer (40 cm) of peat cryozems of flat-topped peat mounds reached 1.24 and 3.20 t/ha, and those in the oligotrophic peat soils (50 cm) of large peat mounds were 2.76 and 1.35 t/ha, respectively. The portion of microbial carbon in the total carbon pool (Cmicr/Ctot, %) varied significantly; according to the values of this index, the soils were arranged into the following sequence: oligotrophic peat soil < peat cryozem < podzol. 相似文献
9.
Gudny Okkenhaug Andreas Botnen Smebye Thomas Pabst Carl Einar Amundsen Hilmar Sævarsson Gijs D. Breedveld 《Journal of Soils and Sediments》2018,18(11):3310-3323
Purpose
Small arm shooting ranges located in peatland areas are gathering increased attention due to severe metal and antimony (Sb) contamination and challenging conditions for remediation. The goal of the present study was to gain further understanding of the distribution, binding and transport of lead (Pb), copper (Cu) and Sb in peatland contaminated by small arm shooting range activities.Materials and methods
A field experiment was carried out at a recently closed shooting range facility in Norway, including (i) peat soil sampling for various selective extractions (water, chemical extractions, extractions by diffusive gradients in thin films, DGT), (ii) establishing groundwater wells for groundwater sampling and monitoring of groundwater level and (iii) sampling of water and sediments in surface water. The results from groundwater monitoring were used to carry out hydrogeological numerical simulations using Seep/W and CTran/W. These models were used to evaluate the residence time of the contaminants in the peatland.Results and discussion
Increased metal concentrations were observed in the top layer of the peatland, indicating low vertical transport. Groundwater revealed high concentrations of Pb (22 ± 5 μg/L), Cu (16 ± 6 μg/L) and Sb (11 ± 2 μg/L), the dominating contaminant source to the downstream surface water. Hydrogeological modelling indicated that transport mainly happened in the upper peat layer, as a result of a higher hydraulic conductivity close to the surface and a high groundwater table. Pb (6.9 ± 0.1 μg/L), Cu (24.0 ± 0.0 μg/L) and Sb (7.4 ± 0.1 μg/L) concentrations in the stream samples confirmed the spreading of contaminants at levels toxic to aquatic organisms. Pb and Cu were most likely associated with dissolved organic carbon (DOC), whereas Sb showed no correlation with DOC.Conclusions
The elements contaminating the peatland may leak to the nearby water course over a long-term period. Copper showed the highest concentration in the stream water despite considerably higher levels of Pb in the peat soil. Strong complexation of Cu to dissolved organic matter might explain this observation. Only a little fraction of the contaminants is transported in a particulate form, and therefore are increased sedimentation measures not considered as viable remediation option.10.
Brännvall M.-L. Bindler R. Emteryd O. Nilsson M. Renberg I. 《Water, air, and soil pollution》1997,100(3-4):243-252
We compare lead concentration and stable lead isotope analyses from three peat bog and three lake sediment records in Sweden. Radiocarbon dated stratigraphies give evidence that trends in the concentration of Pb in the peat and sediment cores are very similar, and follow the general outline of historical global Pb production over several thousand years. Due to the large difference in the 206Pb/207Pb ratio between Sweden, about 1.5, and continental Europe (excluding Fennoscandia), ≤1.2, it is possible to distinguish external sources of Pb to Sweden. In the lake sediments, profiles of 206Pb/207Pb ratio mirror the Pb concentration until 1000 AD; increasing concentration is accompanied by decreasing ratios. After 1000 AD the ratio varies little at about 1.2 in sediments, because of the near total dominance of pollutant Pb. There is a further decline in the Pb ratio to about 1.14 in this century as a result of the addition of alkyl-Pb in petrol. The Pb concentration profiles in the peat match the lakes, but the isotope profiles do not. During the fen-to-bog transition there is a rapid decline in the 206Pb/207Pb ratio from >1.3 to about 1.2, and the ratio continues to decline to the present. We hypothesise that this is because externally-derived Pb from long-range transport of soil dust and atmospheric pollution has always been more important in the ombrotrophic peat than in lakes, which have a greater influx of catchment-derived Pb. 相似文献
11.
Nineteen elements were quantitatively determined by atomic emission spectroscopy with inductively coupled plasma in peat profiles in Ringinglow Bog, Derbyshire, England. For the elements Ba, Ca, Cd, Co, Cr, Fe, La, Mn, Ni, Ti, and Zn an enrichment in the upper 5 cm of the peat bogs was found probably caused by anthropogenic influences. The elements Al, Be, Cu, and Pb showed a different distribution pattern with maximum concentration in the 5 to 15 cm layer. The elements Mg, Na, and Sr showed no enrichment in the upper 55 cm of the peat reflecting the constant input of these elements from the sea during the last few centuries. Upper parts (leaves and stems) of the plants investigated (Calluna vulgaris and Eriophorum vaginatum) only represent higher values of Pb compared with the normal element content in other plants. Compared with the results of peat profiles in a Norwegian bog, the concentrations of the comparable elements (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) are much higher in the English peat. Ringinglow Bog seem to be very suitable for further investigations within the scope of a global monitoring programme. 相似文献
12.
A unique artefact — the fragment of a bow made of yew wood, indicating the hunting activity of prehistoric man — was found within the sediments of the landslide peat bog (at the depth of 330 cm) formed on the Mt. Kamiennik (Polish Flysch Carpathians). The datings of this artefact using 14C method at ca 3790–3380 cal BC indicate its connection with the activity of the Neolithic man, related to the Funnel Beaker Culture. In the sequence of the peat bog deposits formed since the Atlantic Phase, the palaeoclimatic changes of the Middle- and Late Holocene, as well as traces of human impact in these and subsequent periods were recorded and analysed using palynological, macrofossils, lithological methods, and dated with radiocarbon. Palaeoenvironmental changes identified in the peat horizon bearing the artefact were marked by the delivery of minerogenic, “high energy” deposits (with charcoal) to the peat bog, as well as distinct changes of plant communities. These phenomena confirm a significant human impact caused by the Prehistoric man on landslide areas. On the other hand, the study confirms significant importance of climatic condition for human activity and proves that landslide peat bog deposits are very sensitive records of palaeoenvironmental changes. The archaeological artefact essentially supplements the results of our interdisciplinary palaeoenvironmental study. It is one of the rare Neolithic bows found in the area of Europe, till now. 相似文献
13.
Subsidence rates and carbon loss in peat soils following conversion to pasture in the Waikato Region, New Zealand 总被引：1，自引：0，他引：1
Abstract. Drainage of peat soils for agriculture can lead to large carbon losses due to oxidation of peat. We estimated peat subsidence rates and total carbon losses, due to 40 years of dairy farming on a former peat bog, by measuring the thickness of peat and total carbon of farmland and of an adjacent unmodified peat bog above a marker tephra layer that was deposited about 200 AD. Subsidence rates averaged 3.4 cm yr–1 (95% confidence interval of 3.2 to 3.5 cm yr–1 ) and carbon loss averaged 3.7 t ha–1 yr–1 (95% confidence interval of 2.5 to 5.0 t ha–1 yr–1 ). On average, 63% of the subsidence was due to consolidation, with the remainder (37%) attributed to losses of organic matter due to peat mineralization. 相似文献
14.
The distribution of pollutant heavy metals (Cu, Zn, Ni, Cd, and Pb) was determined in 11 acidic virgin peat profiles located along two transects moving away from a smelter plant in the Noranda region of Quebec. The levels of all five metals were found highest in the 0 to 15 cm layer at site near the smelter, and decreased progressively with the distance from the smelter, up to 42 km. Copper had the highest concentrations (5525 μg g?1) followed by Pb and Zn. The maximum levels of total metals built up in the peat surface near the smelter were high, approximately reaching the threshold limits for phytotoxicity in peat soils. The amounts of heavy metals moving down and accumulating in the anaerobic zone of the peat profiles were limited. The distribution and enrichment ratios in the profiles showed that Cu, Zn, and Cd would have relatively higher mobility than Pb. 相似文献
15.
In the lower part of a raised bog profile from Langegger Filz, southern Bavaria, the Pb and Cd concentrations were comparatively low while considerably higher concentrations of both elements were observed in the upper section of the profile. The peat layers with the highest concentrations of Pb and Cd were found to date from the Iron Age, the Roman Age, and the Middle Ages. The Fagus pollen curve reflects the beginning of a beech decline exactly in those peat layers in which the start of the Pb increase is visible. Therefore it appears that metal smelting caused a local release of heavy metals which were subsequently deposited in the raised bog. Metals could only be smelted when wood was cut and burned, and beech charcoal was preferred as it produces relatively high temperatures. The good agreement between the Pb concentration profile and the pollen analyses suggests that the bog provides an accurate record of atmospheric Pb deposition. 相似文献
16.
The active growth and development of psychrotolerant actinomycetes take place in peat and podzolic soils of the tundra and
taiga at temperatures below 10°C. The population density of psychrotolerant mycelial prokaryotes in these soils reaches thousands
and tens of thousands of CFU/g of soil, and the length of their mycelium is up to 380 m/g of soil. The application of fluorescent
in situ hybridization (the FISH method) demonstrated that the metabolically active psychrotolerant representatives of the
phylogenetic group of Actinobacteria comprise up to 30% of the total number of bacteria in prokaryotic microbial communities
of oligotrophic peat bog and podzolic soils. The portion of metabolically active mycelial actinobacteria exceeds the portion
of unicellular actinobacteria. Psychrotolerant streptomycetes isolated from peat bog soils possess pectinolytic, amylolytic,
and antagonistic activities at low temperatures (5°C). 相似文献
17.
Stratigraphical (temporal) and physicochemical investigations of different European peat bogs confirm interrelations between increased ash and element concentrations on the one hand and human settlement (found by means of pollen analysis) on the other hand. Phases of enhanced anthropogenic activities (farming, forest clearing, forestry etc.), which can be derived from the corresponding pollen diagrams and by radiocarbon dating, agree well with the increase in soilborne elements (soil dust Pb, Si, Ti) in the peat profiles. The Pb concentrations of the investigated peat layers have been increasing since Roman Times. Changes in the Pb/Ti ratio help to discriminate between soil dust Pb and Pb from ore mining and smelting. Moreover, this approach reveals measurable Pb pollution extending as far back as the Bronze Age (approx. 2nd Millenium B.C.). Some peat bogs show increased Cu concentrations as far back as the Bronze Age. 相似文献
18.
Ukonmaanaho L. Nieminen T. M. Rausch N. Shotyk W. 《Water, air, and soil pollution》2004,158(1):277-294
The concentrations and vertical distribution of Cu, Ni, Zn, Pb and As were studied in four different ombrotrophic peat bogs with varying heavy metal loads at Hietajärvi, Outokumpu, Harjavalta and Alkkia in Finland. At each site a peat sample (15 cm × 15 cm × 100 cm) was taken using a Titanium Wardenaar corer, and the samples were cut into 5 cm slices. Dried and milled samples were determined by X-ray fluorescence (XRF). The mean concentrations of the elements were at their highest at Harjavalta (the most polluted area), apart from Cu which had the highest value at the Cu-treated site at Alkkia. Cu concentrations were above the lowest effective limit (LOEL) on all the plots except for the background plot at Hietajärvi. The maximum Cu values were reached in the topmost 20 cm layer, indicating the effects of mining and smelting activities. The highest Zn and Ni concentrations occurred in the 0–40 cm layer. At all sites, the maximum Pb concentrations were located between 10 and 50 cm. However, the Pb concentrations were higher at Alkkia and Harjavalta than at Outokumpu and Hietajärvi, indicating anthropogenic sources of Pb at the former sites. The As concentration was also the highest in the uppermost peat layers. The mean concentrations were markedly lower in the deeper layers (40–80 cm) than in the upper layers. 相似文献
19.
Melanie A. Vile Martin J. V. Novák Eva BŘízová R. Kelman Wieder William R. Schell 《Water, air, and soil pollution》1995,79(1-4):89-106
Lead-210 dating of peat cores is one approach that has been used to arrive at historical rates of heavy metal deposition. Despite concerns regarding the validity of210Pb dating due to Pb mobility,210Pb dating can be used if the dates are corroborated with some other independent dating technique. In this study, based on analyses of210Pb dated, pollen corroborated peat cores from two sites in the Czech Republic (Jezerní sla and Bo?í Dar Bog), we illustrate a previously unexplored problem concerning the computation of metal deposition, using Pb as an example. When peat cores are collected, sectioned into depth intervals,210Pb dated and analyzed for metal contents, the210Pb dates most appropriately correspond to the midpoint depth for each interval, whereas the metal contents correspond to the interval between the top and bottom of each section. Thus the210Pb dates and metal content values throughout the core are offset by half the distance of each depth interval. In calculating historical rates of heavy metal deposition two approaches are available for correcting for the depth interval offsets, the traditional approach of date interpolation and our newly proposed metal content interpolation. We see noa priori reason for choosing one approach over the other, and suggest simultaneous use of both date and metal content interpolation. Additionally, acid-insoluble ash (AIA), which has been proposed as a dating technique in and of itself, may be more useful as an interpretive tool which may provide insights into the nature or sources of atmospherically deposited Pb. For example, plots of Pb content per core section versus AIA content per core section for Jezerní slat, located in a relatively pristine area, reveal increased Pb content without increased AIA contents in depths shallower than 6 cm, indicating deposition of gasoline-derived Pb after its introduction in 1922. Similar plots for Bo?í Dar Bog, located in a polluted industrialized region, indicate greater inputs of Pb than would be predicted from AIA, based on the Jezerní sla analyses. We interpret the apparent excess Pb deposition at Bo?í Dar Bog as being contributed by soil-derived dust from local metal mining. Elevated rates in Pb deposition at Bo?í Dar Bog are consistent with the history of local mining known to have occurred in the vicinity. Finally, magnetic susceptibility measurements identify combustion of fossil fuels as a source of atmospheric Pb deposition at Bo?í Dar Bog, but not at Jezerní sla 相似文献
20.
Flameless atomic absorption spectrometry is applied for the determination of Pb in coal, coal ash and fly ash. Lead concentrations in coal and coal ash ranging from respectively 7 to 110 µg g?1 and 120 to 450 µg g?1 are found. A mean concentration of 1520 µg g?1 in fly ash corresponding to a concentration of 117 µg m?3 in the effluent gas suggests the importance of coal combustion as an atmospheric source of Ph. The contribution of coal combustion to the total Pb emissions is conservatively estimated at 6%. 相似文献