Use of 206Pb/207Pb ratios to investigate the surface integrity of peat cores used to study the recent depositional history and geochemical behaviour of inorganic elements in peat bogs

Reconstructing historical Pb and Hg pollution in NW Spain using multiple cores from the Chao de Lamoso bog (Xistral Mountains)

“…This result is not in agreement with investigations in the UK and Sweden, which record a return to more radiogenic ratios in the uppermost peat samples and the overlying plant material accompanying the decrease in Pb concentrations (Farmer et al, 2002;Bindler et al, 2004;Cloy et al, 2008). Farmer et al (2006) also detected a lack of reversal in the isotope ratio in one of the cores they analyzed at Flanders Moss, together with a radionuclide inventory deficit, which led them to the conclusion that the record was incomplete (25 ± 7 years). This may not be the case for the Chao de Lamoso bog, because it is unlikely that the integrity of all four cores analyzed was affected, and because the two cores of our series previously investigated by Olid et al (2008) had an average 210 Pb inventory (143 ± 9 Bq m À2 year À1 ) that matched the expected flux for the area.…”

“…The logical step, as indicated by Bindler et al (2004), is to increase the number of sampling sites and employ larger data sets in making reconstructions. This has been done in a few studies by analyzing replicate cores from the same bog (Benoit et al, 1998;Bindler et al, 2004;Coggins et al, 2006;Farmer et al, 2006), or by analyzing cores from different bogs of the same area (Bindler et al, 1999;Klaminder et al, 2003;Novák et al, 2003;Cloy et al, 2008).…”

Major and trace elements of a peat core from Yunnan, Southwest China: Implications for paleoclimatic proxies

“…It is thus likely that the Pb in peats is largely from organic materials. Pb is among the most concerned elements in peats, and both Pb concentrations and isotopes have been broadly used in tracing anthropogenic impacts on the environment, in particular atmospheric inputs by anthropogenic activities (Farmer et al, 2006;Kamenov et al, 2009;Shotyk et al, 2001). The likely enrichment of Pb by organic materials, shown in our analysis, suggests on the one hand, that Pb in peats and organic rich sediments is indeed sensitive to changes in environmental Pb due to the accumulation ability of plants.…”

“…In ombrotrophic peat bogs, inorganic materials are believed to be mainly atmospheric deposits, and their elemental and isotopic compositions probably indicate changes in atmospheric inputs. Numerous studies in the past decades have described the changes in atmospheric imported heavy metals, such as lead and mercury, during industrial eras or during pre-industrial periods in Europe and North America (Farmer et al, 2006;Kamenov et al, 2009;Kempter et al, 1997;Kylander et al, 2005Kylander et al, , 2007Le Roux et al, 2004;Martinez-Cortizas et al, 1999Roos-Barraclough et al, 2002;Shotyk et al, 1998Shotyk et al, , 2001Shotyk et al, , 2005Weiss et al, 1997Weiss et al, , 1999. These studies of natural and anthropogenic inputs from the atmosphere are important in the evaluation of the impact of human activities on the environment.…”

Comparison of beta (LSC) and gamma (HPGe) spectrometric methods for lead-210 in chronological study

“…210 Pb dating depends on the accurate determination of the level of unsupported 210 Pb in a series of sediment samples, what is quite problematic because of sampling and analytical limitations (MacKenzie et al, 2011). Loss of surface material during sediment sampling can generate inaccuracies in chronology as described by Farmer et al (2006). The validation of chronology based on 210 Pb dating models for the second half of the 20th century is often achieved by the use of artificial fallout radionuclides (e.g., 137 Cs and 241 Am) from the atmospheric testing of nuclear weapons and/or the Chernobyl accident as independent chronostratigraphic markers (O'Reilly et al, 2011).…”