Olid et al STOTEN 2012 (original) (raw)
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Water Air and Soil Pollution, 1995
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 BoŽí 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 BoŽí 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 BoŽí Dar Bog as being contributed by soil-derived dust from local metal mining. Elevated rates in Pb deposition at BoŽí 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 BoŽí Dar Bog, but not at Jezerní sla
Science of The Total Environment, 2002
Two ombrotrophic peat bogs in Northwestern Spain provided a history of 4600 years of Pb accumulation. Highest Pb concentrations (84-87 mg g ) were found near the bogs' surface, but there were also other significant peaks y1 (6-14 mg g ), indicating pre-industrial atmospheric pollution. The enrichment factors (EFs) in both cores show a y1 remarkably similar record. Atmospheric Pb pollution dates back to at least approximately 2500 years ago, reaching a first maximum during the Roman period. For the last 300 years, Pb EFs significantly increased due to industrial development, but the uppermost samples of the bogs show decreasing Pb EFs, probably due to the phasing out of leaded gasoline. These results are also supported by Pby Pb isotope ratios, as they continuously decrease from 206 207 ca. 3000 BP until 2000 BP (from 1.275 at 4070 C years BP to 1.182), indicating the growing importance of non-14 radiogenic Pb released from Iberian ores by ancient mining. Peat samples at a 3-5-cm depth are even less radiogenic ( Pby Pbs1.157), indicating the strong influence of leaded gasoline. Despite the common history shared by the 206 107
Earth and Planetary Science Letters, 2005
Pb pollution has existed for several millennia and remains relevant today. By using peat cores as environmental archives it is possible to reconstruct this long history on a regional scale. This is a significant contribution to the findings from ice core records, the only other archive recording purely atmospheric additions. Without information that allows linking and comparison between sites regionally, within Europe and elsewhere, our ability to make coherent global models of the natural Pb cycle, and anthropogenic forcing of this cycle, is limited. In this respect, the characteristics of the Pb pre-pollution aerosol (PPA) are important to define globally. We characterize for the first time a PPA in Southern Europe with [Pb] = 0.78 F 0.86 Ag g À 1 , net Pb accumulation rates of 0.032 F 0.030 mg m À 2 y À 1 and a 206 Pb / 207 Pb signature of 1.25470 F 0.02575. This PPA Pb isotope signature is more radiogenic than that found thus far in Western and Northern Europe. Spain is a historically important mining site. Using three-isotope plots and a pool of potential Pb isotope signatures, a detailed source appointment of both natural and anthropogenic Pb sources was made. We found evidence of Saharan aridification and its termination~4400 BP and/or agricultural signals and strong local control (from rock and soil) of the Pb PPA. Human impact is first recorded at 3210 BP but does not exceed 50% of deposited Pb until 3005 BP. Mines in SE Spain dominate early Pb pollution history at this site. During the rise of Roman rule, contributions come from mines in N, NW and SW Spain with no strong indication of other European mining activities. In Medieval and Industrial times local contributions to the peat bog are reduced. D 2005 Published by Elsevier B.V.
Atmospheric Environment, 2008
Vertical Pb concentration gradients and isotope ratios (206 Pb/ 207 Pb, 208 Pb/ 207 Pb) are reported for five 210 Pb-dated Sphagnum peat profiles. The studied peat bogs are in the British Isles (Thorne Moors, England; Mull, Scotland; and Connemara, Eire) and central Europe (Ocean, northern Czech Republic; Rybarenska slat, southern Czech Republic). Both the U.K. and the Czech Republic experienced maximum Pb emissions from Ag-Pb smelting around 1880. Pb emissions from coal burning peaked in 1955 in the U.K. and in the 1980s in the Czech Republic. In both countries, use of alkyl-lead additives to gasoline resulted in large Pb emissions between 1950 and 2000. We hypothesized that peaks in Pb emissions from smelting, coal burning and gasoline burning, respectively, should be mirrored in the peat profiles. However, a more complicated pattern emerged. Maximum annual Pb accumulation rates occurred in 1870 at Ocean, 1940 at Thorne Moors, 1988 at Rybarenska slat, and 1990 at Mull and Connemara. Atmospheric Pb inputs decreased in the order Thorne Moors ! Ocean > Rybarenska slat > Mull > Connemara. The Ocean bog was unique in the central European region in that its maximum Pb pollution dated back to the 19th century and coincided with maximum Pb smelting at Freiberg and Pribram. In contrast, numerous previously studied sites showed no Pb accumulation maximum in the 19th century, but increasing pollution until the 1980s. It remains unclear why Ocean did not record the regional peak in Pb emissions caused by high coal and gasoline burning around 1980, while an array of nearby bogs studied previously did record the 1980 coal/gasoline peak, but no 1880 smelting peak. Mean 206 Pb/ 207 Pb ratios of potential pollution sources were 1.07 and 1.11 for gasoline, 1.17 and 1.17 for local ores, and 1.18 and 1.19 for coal in the U.K. and the Czech Republic, respectively. The calculated percentages of gasoline-derived Pb in peat (55% for the British Isles and 63% for the Czech Republic) were surprisingly low. An explanation for the low percentage of gasoline-derived Pb in peat can be more easily found for the Czech sites (until 1989 Czechoslovakia was the third largest lignite producer in the world). Regional differences in deposition rates of gasoline-derived Pb in the U.K. need further study.
Global Biogeochemical Cycles, 2008
Cores collected from ombrotrophic peat bogs in west central, east central, northeast and southwest Scotland were dated (14 C, 210 Pb) and analyzed (ICP-OES, ICP-MS) to derive and compare their historical records of atmospheric anthropogenic Pb deposition over the past 2500 years. On the basis of Pb isotopic composition (e.g., 206 Pb/ 207 Pb), clear indications of Pb contamination during the pre-Roman/Roman, post-Roman and medieval periods were attributed to the mining and smelting of Pb ores from Britain and elsewhere in Europe. Between the 17th and early 20th centuries, during the industrial period, the mining and smelting of indigenous Scottish Pb ores were the most important sources of anthropogenic Pb deposition at three of the sites. In contrast, at the most southerly site, influences from the use of both British Pb ores and imported Australian Pb ores (in more southern parts of Britain) since the late 19th century were evident. At each of the sites, Australian-Pb-influenced car exhaust emissions (from the 1930s to late 1990s), along with significant contributions from coal combustion (until the late 1960s and onset of the postindustrial period), were evident. Atmospheric anthropogenic Pb deposition across Scotland was greatest ($10 to 40 mg m À2 a À1) between the late 1880s and late 1960s, increasing southward, declining to 0.44 to 5.7 mg m À2 a À1 by the early 2000s. The records from four peat bogs extend knowledge of the chronology of atmospheric Pb deposition trends across the northern hemisphere, there being general agreement with other environmental archive records from not only Scotland but also other countries in western Europe and Greenland. Nevertheless, during all periods investigated here, the isotopic composition of atmospheric Pb deposition across western Europe and Greenland exhibited variations in the relative importance of different sources of anthropogenic Pb, as well as some differences in timings and magnitudes of anthropogenic Pb contamination, arising from variations in local and regional sources of Pb deposition and possibly climatic regimes.
Atmospheric Environment, 2005
In a peat bog from Black Forest, Southern Germany, the rate of atmospheric Pb accumulation was quantified using a peat core dated by 210Pb and 14C. The most recent Pb accumulation rate (2.5 mg m−2 y−1) is similar to that obtained from a snowpack on the bog surface, which was sampled during the winter 2002 (1 to 4 mg m−2 y−1). The Pb accumulation rates recorded by the peat during the last 25 yr are also in agreement with published values of direct atmospheric fluxes in Black Forest. These values are 50 to 200 times greater than the “natural” average background rate of atmospheric Pb accumulation (20 μg m−2 y−1) obtained using peat samples from the same bog dating from 3300 to 1300 cal. yr B.C. The isotopic composition of Pb was measured in both the modern and ancient peat samples as well as in the snow samples, and clearly shows that recent inputs are dominated by anthropogenic Pb. The chronology and isotopic composition of atmospheric Pb accumulation recorded by the peat from the Black Forest is similar to the chronologies reported earlier using peat cores from various peat bogs as well as herbarium samples of Sphagnum and point to a common Pb source to the region for the past 150 years. In contrast, Pb contamination occurring before 1850 in southwestern Germany, differs from the record published for Switzerland mainly due to the mining activity in Black Forest. Taken together, the results show that peat cores from ombrotrophic bogs can yield accurate records of atmospheric Pb deposition, provided that the cores are carefully collected, handled, prepared, and analysed using appropriate methods.
Environmental Science & Technology, 2003
Lead originating from coal burning, gasoline burning, and ore smelting was identified in 210 Pb-dated profiles through eight peat bogs distributed over an area of 60 000 km 2. The Sphagnum-dominated bogs were located mainly in mountainous regions of the Czech Republic bordering with Germany, Austria, and Poland. Basal peat 14 C-dated at 11 000 years BP had a relatively high 206 Pb/ 207 Pb ratio (1.193). Peat deposited around 1800 AD had a lower 206 Pb/ 207 Pb ratio of 1.168-1.178, indicating that environmental lead in Central Europe had been largely affected by human activity (smelting) even before the beginning of the Industrial Revolution. Five of the sites exhibited a nearly constant 206 Pb/ 207 Pb ratio (1.175) throughout the 19th century, resembling the "anthropogenic baseline" described in Northern Europe (1.17). At all sites, the 206 Pb/ 207 Pb ratio of peat decreased at least until 1980; at four sites, a reversal to more radiogenic values (higher 206 Pb/ 207 Pb), typical of easing pollution, was observed in the following decade (1980-1990). A time series of annual outputs for 14 different mining districts dispersing lead into the environment has been constructed for the past 200 years. The production of Ag-Pb, coal, and leaded gasoline peaked in 1900, 1980, and 1980, respectively. In contrast to other European countries, no peak in annual Pb accumulation rates was found in 1900, the year of maximum ore smelting. The highest annual Pb accumulation rates in peat were consistent with the highest Pb emission rates from coal-fired power plants and traffic (1980). Although maximum coal and gasoline production coincided in time, their isotope ratios were unique. The mean measured 206 Pb/ 207 Pb ratios of local coal, ores, and gasoline were 1.19, 1.16, and 1.11, respectively. A considerable proportion of coal emissions, relative to gasoline emisions, was responsible for the higher 206 Pb/ 207 Pb ratios in the recent atmosphere (1.15) compared to Western Europe (1.10). As in West European countries, the gasoline sold in the Czech Republic during the Communist era (1948-1989) contained an admixture of low-radiogenic Precambrian lead from Australia.