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Thoni L.,Research Group for Environmental Monitoring FUB | Yurukova L.,Bulgarian Academy of Science | Bergamini A.,Research Group for Environmental Monitoring FUB | Ilyin I.,Meteorological Synthesizing Center East of | Matthaei D.,Research Group for Environmental Monitoring FUB
Atmospheric Environment | Year: 2011

Owing to their ability to accumulate heavy metals, mosses are especially suitable to monitor heavy metal airborne pollution. In Europe, starting in 1990 within the framework of UNECE ICP-Vegetation, the monitoring of background heavy metal deposition based on concentrations found in mosses were performed every five years in Switzerland, and, since 1995 also Bulgaria. Here we compare spatial and temporal trends of heavy metal depositions in these two countries and we assess to what extent a large scale European deposition model (MSCE-HM model) can be applied on these two countries.Highly significant differences in concentrations in mosses between the two countries were found for Cd, Cu, Ni, V, Cr, Fe, Pb. For Zn the differences were less clear, but still significant in 2000 and 2005. In Bulgaria, with the exception of Cr, heavy metal concentrations decreased between 1995 and 2005 (-14% to -29%). In Switzerland, Cd (-38%), Pb (-63%) and V (-23%) showed the strongest decrease between 1995 and 2005. For Fe, Ni and Zn no or only small concentration changes were found, whereas a considerable rise was recorded for Cr (+65%) and Cu (+15%). In comparison to median heavy metal concentrations in Europe, concentrations in Bulgaria were nearly always higher, while concentrations in Switzerland were always lower. For both Pb and Cd, relationships between modelled and moss-derived values for all of the years were highly significant, but explained variances were rather low. Overall, relationships between moss-derived depositions and modelled depositions were rather close to a 1:1-relationship in Switzerland. In Bulgaria the modelled depositions were considerably lower than the moss-derived depositions.Although deposition levels in Bulgaria also decreased, heavy metal concentrations in mosses were still high. In contrast to Switzerland, Bulgaria has a strong non-ferrous and ferrous heavy industry. New technologies must be implemented in order to reduce deposition levels in Bulgaria. Continuing the moss monitoring is crucial for future evaluations of environmental measures. © 2011 Elsevier Ltd. Source

Schroder W.,University of Vechta | Pesch R.,University of Vechta | Harmens H.,UK Center for Ecology and Hydrology | Fagerli H.,Norwegian Meteorological Institute | Ilyin I.,Meteorological Synthesizing Center East of
Environmental Sciences Europe | Year: 2012

Within the framework of the Convention of Long-range Transboundary Air Pollution atmospheric depositions of heavy metals and nitrogen as well as critical loads/levels exceedances are mapped yearly with a spatial resolution of 50 km by 50 km. The maps rely on emission data and are calculated by use of atmospheric modelling techniques. For validation, EMEP monitoring data collected at up to 70 sites across Europe are used. This spatially sparse coverage gave reason to test if the chemical and physical relations between atmospheric depositions and their accumulation in mosses collected at up to 7000 sites throughout Europe can be quantified in terms of statistical correlations which, if proven, could be used to calculate deposition maps with a higher spatial resolution. Indeed, combining EMEP maps on atmospheric depositions of cadmium, lead and nitrogen and the related maps of their concentrations in mosses by use of a Regression Kriging approach yielded deposition maps with a spatial resolution of 5 km by 5 km. Since spatial autocorrelation can make testing of statistical inference too liberal, the investigation at hand was to validate the 5 km by 5 km deposition maps by analysing if spatial auto-correlation of both EMEP deposition data and moss data impacted on the significance of their statistical correlation and, thus, the validity of the deposition maps. To this end, two hypotheses were tested: 1. The data on deposition and concentrations in mosses of heavy metals and nitrogen are not spatially auto-correlated significantly. 2. The correlations between the deposition and moss data lack of statistical significance due to spatial autocorrelation. Results As already published, the regression models corroborated significant correlations between the concentrations of heavy metals and nitrogen in atmospheric depositions on the one hand and respective concentrations in mosses on the other hand. This investigation proved that atmospheric deposition and bioaccumulation data are spatially auto-correlated significantly in terms of Moran's I values and, thus, hypothesis 1 could be rejected. Accordingly, the degrees of freedom were reduced. Nevertheless, the results of the calculations regarding the reduced degrees of freedom indicate that the statistical relations between atmospheric depositions and bioaccumulations remained statistically significant so that hypothesis 2 could be rejected, too. Conclusions The positive auto-correlation in data on atmospheric deposition and bioaccumulation does not call for a revision of the 5 km by 5 km deposition maps published in recent papers. Therefore we can conclude that the European moss monitoring yields data that support the validation of modelling and mapping of atmospheric depositions of heavy metals and nitrogen at a high spatial resolution compared to the 50 km × 50 km EMEP maps. © 2012 Schröder et al. Source

Schroder W.,University of Vechta | Pesch R.,University of Vechta | Holy M.,University of Vechta | Genssler L.,Obmann Arbeitskreis Bioindikation und Wirkungsermittlung der Landesanstalten und Amter | And 2 more authors.
Environmental Sciences Europe | Year: 2012

Every five years since 1990, the European moss surveys provide data on concentrations of heavy metals and since 2005 on nitrogen (N) in mosses. Germany participated in the monitoring campaigns 1990-2005. As part of a series reporting the trends for Germany and single federal states, this article is on North Rhine-Westphalia showing that the metal concentrations decreased from 1990 to 2000 for all elements but Zn. From 2000 to 2005 an increase can be stated for As, Cr, Cu, Ni, Sb, Zn and the Multi Metal Index MMI1990-2005. The N concentration reaches from 1.08 to 2,29 % in dry mass showing significant correlations to the agriculture density (+), the height of the surrounding trees (+), the forests density (-), the distance to trees (-), altitude (-) and the precipitation sum for the accumulation period (-). The according correlation coefficients (Spearman) reach from rs 0.32 to 0.49 (p < 0.01). The correlation of the metal loads in the mosses and land use characteristics in the vicinity of the sampling sites lie between rs = 0.21 and rs = 0.54 (0.01 < p < 0.05). The type of moss species and the moss growth patterns are associated to a similar degree (Cramér's V-values between 0.27 and 0.56). Of all investigated site specific information on forest density (Cd, Cu, Pb, Zn, N), urban density (As, Cd, Cr, Cu, Fe, Ni, Ti, Zn), precipitation (As, Cd, Cr, Cu, Fr, Hg, Ni, Pb, Ti, V, Zn, N), altitude (As, Cd, Cr, Cu, Fr, Ni, Ti, Zn, N) and the distance of the sampling site to roads (Cr, Fe, Ni, Ti), trees or bushes (As, Cd, Cr, Cu, Fe, Ni, Zn) are those showing significant correlations to most elements. The urban land use density in a radius of 5 km around the sampling site as well as altitude and the distance of the sampling site to nearby trees are the statistically most significant factors for the Cu concentrations in mosses sampled in 2005. The total deposition of Cd (EMEP) and Cd concentrations in mosses are correlated significantly (0.57 ≤ r s ≥ 0.71, p < 0.01). © 2012 Schroder et al. Source

Goodsite M.E.,University of Aarhus | Outridge P.M.,University of Aarhus | Outridge P.M.,Geological Survey of Canada | Christensen J.H.,University of Aarhus | And 4 more authors.
Science of the Total Environment | Year: 2013

This review compares the reconstruction of atmospheric Hg deposition rates and historical trends over recent decades in the Arctic, inferred from Hg profiles in natural archives such as lake and marine sediments, peat bogs and glacial firn (permanent snowpack), against those predicted by three state-of-the-art atmospheric models based on global Hg emission inventories from 1990 onwards. Model veracity was first tested against atmospheric Hg measurements. Most of the natural archive and atmospheric data came from the Canadian-Greenland sectors of the Arctic, whereas spatial coverage was poor in other regions. In general, for the Canadian-Greenland Arctic, models provided good agreement with atmospheric gaseous elemental Hg (GEM) concentrations and trends measured instrumentally. However, there are few instrumented deposition data with which to test the model estimates of Hg deposition, and these data suggest models over-estimated deposition fluxes under Arctic conditions. Reconstructed GEM data from glacial firn on Greenland Summit showed the best agreement with the known decline in global Hg emissions after about 1980, and were corroborated by archived aerosol filter data from Resolute, Nunavut. The relatively stable or slowly declining firn and model GEM trends after 1990 were also corroborated by real-time instrument measurements at Alert, Nunavut, after 1995. However, Hg fluxes and trends in northern Canadian lake sediments and a southern Greenland peat bog did not exhibit good agreement with model predictions of atmospheric deposition since 1990, the Greenland firn GEM record, direct GEM measurements, or trends in global emissions since 1980. Various explanations are proposed to account for these discrepancies between atmosphere and archives, including problems with the accuracy of archive chronologies, climate-driven changes in Hg transfer rates from air to catchments, waters and subsequently into sediments, and post-depositional diagenesis in peat bogs. However, no general consensus in the scientific community has been achieved. © 2013 Elsevier B.V. Source

Schroder W.,University of Vechta | Pesch R.,University of Vechta | Zechmeister H.,University of Vienna | Kratz W.,University of Vechta | And 4 more authors.
Umweltwissenschaften und Schadstoff-Forschung | Year: 2010

Purpose Under the Convention on Long-range Transboundary Air Pollution mosses are used to map the bioaccumulation of heavy metals and nitrogen throughout Europe. To this end, since 1990 mosses were sampled and analyzed chemically every five years. The goal of this article is to apply the moss survey data for assessing the bioaccumulation of Cd, Pb and N in German Natura 2000 Sites of Community Importance (SCI). Methods The temporal trends of the heavy metal bioaccumulation within SCIs were analyzed using a multi metal index (MMI) calculated by means of geostatistics and percentile statistics. For nitrogen, only monitoring values for 2005 were available for the assessment. The geostatisticall estimated values of the metal and nitrogen concentrations in mosses were transformed to estimated deposition values by use of regression analyses. Subsequently, the results were integrated into the assessment of the German SCIs. Results Highest metal loads within SCIs were detected in 1990, followed by a continuous decrease to 2000 and a significant increase until 2005. Regarding N, a median of 1.5 % nitrogen in the dry mass was calculated. The deposition values calculated from the moss estimates resulted in median values of 0.33 g/ha/a for Cd, 8.2 g/ha/a for Pb and 16.7 kg/ha/a for nitrogen. Conclusions The Moss-Monitoring is the only environmental monitoring programme which enables statistically sound estimations of the exposure of SCI to environmental contaminants in terms of heavy metal and nitrogen deposition and bioaccumulation. © Springer-Verlag 2010. Source

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