Variations in Pb concentration in lake sediments reflect changes in the fluxes of this element in the• past. A sediment core from a lake in the Pyrenees (Lake Redo at 2,240 m a.s.L, N_E Spain) was studied, with the aim of reconstructing pastenvironmenial and climatic conditions in the lake and its catchment area. The core was dated usii1g both 210 Pb and 14 C. A surface peak of Pb concentration, which was about 10 tim~s higher than the background level, was found. This peak is attributed to mining activities since the begioping of this century. Although Pb pollution due to the combustion of gasoline is expected to be present, no evidence can be deduced from Pb isotope ratios of sediment due to the masking effect of Pb from mines. A second peak appeared in a deeper layer, with a maximum Pb concentration of about 17 times higher than the background level. The origin of this peak is unclear. All evidence suggests that the ancient peak is due to mining operations in the central Pyrenees area, which were not documented historically.
The suitability of laser ablation ICP-MS for minor and trace analysis of archaeological iron finds, produced by a direct reduction process in a 'bloomery' furnace, is reported. The analysis of elemental impurities in the iron can provide useful archaeometallurgical information on the production process and the provenance of the iron. Since, even after refinement, the iron resulting from this process may contain many inclusions (slag, charcoal, holes, etc.), a method should be used with sufficient spatial resolution to preclude the inclusions from the analysis. The ablation parameters are selected such that ablation craters of approx. 100 microm in diameter are obtained. The method is validated with low alloy steel and cast iron standard reference materials and by a comparative analysis with electron probe microanalysis (EPMA). The precision is limited mainly by the homogeneity of the iron, rather than by instrumental reproducibility. The advantages and drawbacks of the method are briefly compared with EPMA. Preliminary results from the analysis of archaeological iron samples from excavations at Develier-Courtetelle (Canton Jura, CH), Neftenbach (Canton Zurich, CH), Wartau (Canton St Gallen, CH) and Mont Chemin (Canton Valais, CH) are given.
This paper reports on the performance of solid sampling-electrothermal vaporization-inductively coupled plasma mass spectrometry for the direct multi-element analysis of two different perfluorosulfonic acid/TFE copolymer samples, which were selected in order to test the potential of this technique for routine control of fluorocarbon polymers. Careful selection of the most suitable isotopes permits the reliable monitoring of the analytes of interest: Cr, Cu, Fe, K, Mn, Pb and Zn. The use of Pd as chemical modi. er allows stabilization of all of these analytes during the pyrolysis step (at 800 degrees C), enabling adequate matrix removal, while the use of a high vaporization temperature (2700 degrees C) is required for the efficient simultaneous vaporization of these elements. Moreover, the 105 Pd 1 signal can be used as internal standard, correcting for possible sensitivity drifts. Under these conditions, straightforward calibration with aqueous standard solutions was feasible for all of the elements investigated. The method thus developed exhibits interesting features, such as a low detection limit (ng g(-1) range) for most elements, a high sample throughput (15 min per determination), a low sample consumption (a few milligrams only), precision values usually in the 7-12% RSD range and the absence of any sample pretreatment, with the subsequent lower risk of analyte losses or contamination. Therefore, it seems to offer a promising alternative for the laborious procedures currently in use for analysis of these complex samples
Variations in Pb concentration in lake sediments reflect changes in the fluxes of this element in the• past. A sediment core from a lake in the Pyrenees (Lake Redo at 2,240 m a.s.L, N_E Spain) was studied, with the aim of reconstructing pastenvironmenial and climatic conditions in the lake and its catchment area. The core was dated usii1g both 210 Pb and 14 C. A surface peak of Pb concentration, which was about 10 tim~s higher than the background level, was found. This peak is attributed to mining activities since the begioping of this century. Although Pb pollution due to the combustion of gasoline is expected to be present, no evidence can be deduced from Pb isotope ratios of sediment due to the masking effect of Pb from mines. A second peak appeared in a deeper layer, with a maximum Pb concentration of about 17 times higher than the background level. The origin of this peak is unclear. All evidence suggests that the ancient peak is due to mining operations in the central Pyrenees area, which were not documented historically.
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