Comment on : “A novel approach to peatlands as archives of total cumulative spatial pollution loads from atmospheric deposition of airborne elements complementary to EMEP data: Priority pollutants (Pb, Cd, Hg)” by Ewa Miszczak, Sebastian Stefaniak, Adam Michczyński, Eiliv Steinnes and Irena Twardowska

Acknowledgements We are thankful to P.G. Appleby, R. Bindler, J. Sonke, B. Smieja-Krol and three anonymous reviewers for their constructive comments.Peer reviewedPostprin

Development of lead-210 measurement in peat using polonium extraction. A procedural comparison

Two chemical treatments for lead-210 measurement were compared on the sub-surface samples of a core from an ombrotrophic bog from East Belgium. The classical procedure involves a concentrated acid extraction of polonium. However, this treatment represents substantial health risks together with unknowns regarding both the degree of cleanliness and the Po extraction rate, and most importantly, is rather time consuming. We developed here an improved procedure involving an ashing step prior to acid extraction. This allows substantial improvements such as: 1/ the use of a relatively small amount of acid compared to the classical procedure and 2/ the substantial reduction of a total sample digestion time. Measurements of 210Pb concentrations were conducted by alpha spectrometry. Results show a good agreement of unsupported 210Pb activity obtained for both procedures, although some unknowns remain concerning the adsorption of 210Po on the plastic test tube, the volatilization of a small amount of ash, or the absorption of alpha particle at the alpha source surface. This however should not affect the 210Pb measurement as all the samples are spiked prior to ashing (i.e. the recoveries are fully monitored). Through this study, we are suggesting researchers to follow this new procedure in order to increase safety, cleanliness, better recovery and substantial time gain

Atmospheric mercury deposition during the last 1500 years in We Europe: The Misten peat bog record (Hautes Fagnes - Belgium)

The current rate of global atmospheric Hg deposition is approximately three times higher than the preindustrial record and it even increased by a factor of 2-10 in the industrialized regions.....()(Hylander and Meili 2003). To determine the extent of such increase, it is necessary to quantify the atmospheric mercury concentration and its temporal variation. For this purpose four 1m Wardenaar peat cores (MIS01W, 04W, 0W5 and 06W) were collected in 2008 in the ombrotrophic Misten bog (Hautes Fagnes Plateau, East Belgium). Mercury was measured using a DMA 80 at the Laboratory of Mechanisms and Transfers in Geology in Toulouse (LMTG, France). The strongest mercury concentrations are measured in the upper half peat record, in a depth interval corresponding to the Industrial Revolution period. Mercury accumulation rate was estimated by applying a coupled 210Pb- 14C age model. The mercury accumulation rate remains relatively small, ranging between 0.9 and 3.3 g.m 2.y 1 during periods corresponding to the decline of Roman Empire and during the Middle Ages. Hg accumulation rate starts to increase when 25 cm, reaching a maximum value (> 115 g.m 2.y 1) at 13.7 cm (i.e.; 1923-1938 AD). Then the values oscillate to reach 9 g.m 2.y 1 at the peat surface (2000-2007AD). In the Misten bog, the evolution of Hg accumulation rate is in agreement with the chronology of other European peat records .......()(Roos-Barraclough et al. 2002)

Dust historical record in ombrotrophic peat: The case study of a NW European bog

Ombrotrophic peatlands are unique environmental archives of natural and anthropogenic atmospheric dust deposition because their surface layers are exclusively fed by atmospheric inputs. Lead (Pb) isotopes have been often used to evidence any anthropogenic influence in peat, but they only record trace metal pollution. Another radiogenic isotope, the Neodymium (Nd), could be also use to discriminate the sources of dust in peat bogs. Dust fluxes were investigated over the last 2500 years in the Misten peat bog in Eastern Belgium. Our aims were to use Nd isotope signature to decipher between local and distal dust supplies, the Pb isotopes to trace the antropogenic influences. To address these aims we analyzed REE and lithogenic element analyses, as well as the Nd and Pb isotopes, using HR-ICP-MS and MC-ICP-MS, respectively in peat layers dated by 210Pb and 14C. Changes in REE concentration variations in peat samples are correlated with Ti, Al, and Zr that are lithogenic conservative elements, suggesting that REE are immobile in the studied peat bogs and can be used as tracers of dust deposition. Dust fluxes show pronounced increase at BC300, AD600, 1000AD, 1200AD and from 1700AD, recording either influence of human activities (regional erosion due to forest clearing and soil cultivation activities) or local and regional climate changes. Lead enrichments reveal strong human impact over the last 300 years. Lead isotope signatures are consistent with local and regional contamination by coal combustion and smelting activities. Neodymium isotopes allow to identify three periods characterised by dominant-distal sources (at 320AD, 1000 AD and 1700AD). Those periods are consistent with local wetter intervals as indicated by lower humification degree. Local erosion prevails durier drier (higher humification) intervals (-100AD, 600AD). On a global scale more distal supplies are driven during colder periods, in particular Oort and Maunder minima, confirming the hypothesis that cold climate conditions favor distal supplies. Combining geochemical elementary content and isotope data in ombrotrophic peat allows to decipher between dust flux changes related to human and climate forcing

Atmospheric trace metal inputs in the Misten bog (East Belgium): Special attention to sampling techniques and site-spatial variability

EGU2010-4097-1info:eu-repo/semantics/publishe

Multiproxy investigation of climatic changes and human activities in a Baltic bog (N. Poland) during the last millennium

the BOG Team EGU2010-4097-1info:eu-repo/semantics/publishe