Long-range Transboundary Air Pollution Research Articles

Dealing with fixed emissions ceilings in an uncertain future: Offsetting under environmental integrity

National emission ceilings are a policy instrument to reduce adverse environmental impacts of transboundary air pollution. Such ceilings for SO2, NOx, NH3 and VOC are established, for example, in the Gothenburg Protocol of the Convention on Long-range Transboundary Air Pollution (UNECE, 1999) and the National Emission Ceilings (NEC) Directive of the European Union (EC, 2001a, b). They prescribe for each pollutant a fixed upper limit on emissions for a specific year. Flexibility in achieving them could lower implementation costs if reality develops differently from what was foreseen during negotiations.In this paper, we explore the conditions under which emission reductions for one pollutant (e.g., SO2) could be offset by additional cuts of another pollutant (e.g., NOx) within the same country, without compromising the environmental improvements that are envisaged from the original set of emission ceilings. We employ the impact module of the GAINS (Greenhouse gas – Air pollution Interactions and Synergies) model to examine possible exchange rates across pollutants for the 2012 negotiations on the revision of the Gothenburg Protocol in Europe.Our analysis shows that exchange rates that satisfy the environmental integrity condition can be established, but that their values vary substantially across countries. Extending the environmental integrity condition to downwind countries will require significantly higher exchange rates. We discuss aspects that decision makers would need to consider before adopting an offsetting schema for future international environmental agreements.

Air pollution study in Macedonia using a moss biomonitoring technique, ICP-AES and AAS

In the framework of the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops under the auspices of the United Nations Economic Commission for Europe (UNECE-ICP Vegetation) Convention on Long-Range Transboundary Air Pollution (LRTAP), in 2002 and 2005, a moss biomonitoring technique was applied to air pollution studies in the Republic of Macedonia. The third moss survey took place in August and September 2010 when 72 samples of the terrestrial mosses Homalothecium lutescens and Hypnum cupressiforme were collected over the territory of the Republic of Macedonia, using the same sampling network grid as for the previous surveys. Using inductively coupled plasma-atomic emission spectrometry (ICP-AES) and atomic absorption spectrometry (AAS), a total of 18 elements (Al, Ba, Ca, Cd, Cr, Cu, Fe, Hg, K, Li, Mg, Mn, Ni, P, Pb, Sr, V and Zn) were determined. To reveal hidden multivariate data structures and to identify and characterize different pollution sources, Principal Component Analysis was used. Distributional maps were prepared to point out the regions most affected by pollution and related to known sources of contamination. As in the previous surveys, the regions near the towns of Skopje, Veles, Tetovo, Radoviš and Kavadarci were found to be most affected by pollution, even though the median elemental content in the mosses in 2010 for Cd, Cr, Cu, Ni, Pb and Zn was slightly lower than in the previous surveys. For the first time, P content in the moss samples was analyzed, and a higher content of this element as well as K in the mosses was observed in the agricultural regions of the country.

Information flows and social capital through linkages: the effectiveness of the CLRTAP network

This paper examines the effectiveness of the convention on long-range transboundary air pollution (CLRTAP) from a network perspective. The authors claim, contrary to most existing research, that we must consider all links and connections that a regime creates among its members for determining whether and how it influences states toward ‘greener’ environmental behavior. To this extent, the paper advances two arguments. First, parties more central to the CLRTAP network can rely on and signal mutual interests, shared preferences, and decreased uncertainty with all actors involved. In turn, a central position embodies social capital, which facilitates that a well-connected state is ceteris paribus more likely to cooperate with the regime. Second, if other countries in the network do not cooperate, however, it is likely that the positive effect stemming from social capital disappears and that a state will defect even if it has a central position in the network. The authors’ empirical analysis provides support for the theory and may have important implications for studies on regime effectiveness and on networks in general.

PM10 emission forecasting using artificial neural networks and genetic algorithm input variable optimization

This paper describes the development of an artificial neural network (ANN) model for the forecasting of annual PM10 emissions at the national level, using widely available sustainability and economical/industrial parameters as inputs.The inputs for the model were selected and optimized using a genetic algorithm and the ANN was trained using the following variables: gross domestic product, gross inland energy consumption, incineration of wood, motorization rate, production of paper and paperboard, sawn wood production, production of refined copper, production of aluminum, production of pig iron and production of crude steel. The wide availability of the input parameters used in this model can overcome a lack of data and basic environmental indicators in many countries, which can prevent or seriously impede PM emission forecasting. The model was trained and validated with the data for 26 EU countries for the period from 1999 to 2006. PM10 emission data, collected through the Convention on Long-range Transboundary Air Pollution — CLRTAP and the EMEP Programme or as emission estimations by the Regional Air Pollution Information and Simulation (RAINS) model, were obtained from Eurostat.The ANN model has shown very good performance and demonstrated that the forecast of PM10 emission up to two years can be made successfully and accurately. The mean absolute error for two-year PM10 emission prediction was only 10%, which is more than three times better than the predictions obtained from the conventional multi-linear regression and principal component regression models that were trained and tested using the same datasets and input variables.

Sources, assessment, remediation and prevention of persistent organic pollutants. The ecocycle-model as a solution. Swedish case studies, environmental monitoring and legislation

Persistent organic pollutants are either deliberately produced substances by the industry for a wide range of applications or occurred as byproducts from various activities, such as industrial or combustion processes. Despite a considerable decrease in POP levels during the last decades, unintentional production and accumulation of these substances still occur, mostly due to uncontrolled combustion processes, the lack of life cycle assessment and long-range transboundary air pollution. Remediation methods (mostly phytoremediation) are being developed in order to reduce POPs in the environment, but there are some legal obstacles of certain methods involving the application of transgenic plants, which might offer a fairly fast solution, provided that the precautionary principle is not compromised. The proper life-cycle analysis of industrial products, the combination of bio-energy crop production, constructed wetlands, reed-beds and phytoremediation resulting in complete agro-ecocycles, may constitute the basis of a sustainable, poison-free society. Sweden has the strictest and most comprehensive environmental legislation in Europe. The Swedish Government commissioned the Swedish Chemicals Inspectorate jointly with the Swedish Environment Protection Agency to prepare a national implementation plan for the Stockholm Convention on Persistent Organic Pollutants. The ecocyclemodel should provide the most suitable solution for reducing the level of POPs or eliminating these substances from the environment.

American business interests meet air pollution transport science: understanding the US response to trans-Pacific air pollution

Since the discovery of air pollution traveling from China to the US during the late 1990s, trans-Pacific air pollution (consisting of a range of non-CO2 greenhouse gases) has been an emerging global environmental issue. But how has it been addressed, how does it relate to the existing multilateral air pollution regime, and who are the interested parties? This article addresses these questions by examining the evolution of the science of trans-Pacific air pollution, discussing the way in which this science has been made policy-relevant by researchers working under the Convention on Long-Range Transboundary Air Pollution, and by illustrating how American economic interests concerned with the effects of trans-Pacific air pollution on American land values and industry have used this scientific knowledge to lobby the US government for regulatory relief. Trans-Pacific air pollution arguably causes regions of the US to violate National Ambient Air Quality Standards, resulting in unwanted federal involvement in local decision-making and tighter regulatory standards, which impedes local economic development and lowers property values. At the same time, laxer environmental standards in China result in increased pollution and lower American industrial competitiveness. The result has been that the US Chamber of Commerce and the Alliance for American Manufacturing have begun to develop policy alternatives.

Global ecopolitics: crisis, governance, and justice

List of Acronyms Preface Acknowledgments 1. Planetary Anxiety and Collective Dilemmas Sovereignty, Global Governance, and Public Goods Shades of Green The Crosscutting Dilemma: Our Growing Numbers Delving Deeper into Global Ecopolitics 2. International Arrangements: Actors and Effectiveness Multi-scaled Adaptive Governance Individuals and Communities Governments and Governance International Law and Institutions Wicked Problems: Measuring Effectiveness in International Arrangements 3. Conserving Biodiversity and Wildlife Rising Concerns: The Historical Context The Convention on Biological Diversity The Convention on International Trade in Endangered Species of Wild Flora and Fauna Redefining the Wealth 4. Deforestation and Land Degradation Deforestation The International Tropical Timber Agreement Desertification The United Nations Convention to Combat Desertification Taking Root 5. Air Pollution and Climate Change Atmospheric Pollution The Convention on Long-Range Transboundary Air Pollution (CLRTAP) The Ozone Layer Arrangement The UN Framework Convention on Climate Change Deep Breaths 6. Blue Peril: Oceans and Rivers The Poles The Oceans Crises UNCLOS Freshwater Scarcity The Veins of Life: Shared River Arrangements Surviving the Tides 7. Trade and the Global Environment Toxic Trade The Basel Convention on Trade in Hazardous Substances The WTO and the Agreement on the Application of Sanitary and Phytosanitary Measures (SPS) Toward Ethical Investments 8. War and Peace and Justice Ecocide: The Circle of Death The Atmospheric Test Ban Treaty The Convention on the Prohibition of Military or Any Other Hostile Use of Environmental Modification Techniques (ENMOD) Toward Environmental Justice and Human Security 9. Another Convention Needed? Invasive Alien Species Invasive Alien Species: The Problem(s) Regional Efforts Toward an International Convention on IAS? 10. Governance Gaps and Green Goals Nanotechnology Global Tourism Food Security A Global Energy Strategy? From Angst to Resolve Afterword: What Can You Do? References Index

Trends of atmospheric deposition of trace elements in Macedonia studied by the moss biomonitoring technique

In 2002 and 2005 the moss biomonitoring technique was applied to air pollution studies in the Republic of Macedonia in the framework of the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops under the auspices of the United Nations Economic Commission for Europe (UNECE-ICP Vegetation) Convention on Long-Range Transboundary Air Pollution (LRTAP). In August 2005 samples of the terrestrial mosses Homolothecium lutescens and Hypnum cupressiforme were collected at 72 sites evenly distributed over the territory of the country, in accordance with the sampling strategy of the European moss survey programme. A total of 41 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, Mo, Cd, Sb, I, Cs, Ba, La, Ce, Sm, Eu, Tb, Dy Hf, Ta, W, Hg, Pb, Th, and U) were determined by instrumental epithermal neutron activation analysis and atomic absorption spectrometry. Principal component analysis was used to identify and characterize different pollution sources. Distributional maps were prepared to point out the regions most affected by pollution and to relate this to known sources of contamination. A few areas, as in 2002, are experiencing particular environmental stress: Veles, Skopje, Tetovo, Radoviš and Kavadarci-Negotino, whereas the agricultural regions in the south, south-west, and south-east show median European values for most elements of mainly pollution origin. A significant increase in the content of Ni is noticed in the 2005 moss survey compared with 2002, due to the increased production of the ferro-nickel smelter in Kavadarci. A higher content of Cd, Hg, and Pb in 2005 relative to 2002 can be explained by pollution from the lead-zinc smelter in Veles, as well as the pollution that comes from the open slag waste dump of this smelter. Protection activities on the dump of slag from the former ferrochromium smelter located near Tetovo resulted in a lower content of Cr in the 2005 moss survey.

Does spatial auto-correlation call for a revision of latest heavy metal and nitrogen deposition maps?

Abstract Background Within the framework of the Convention on 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 auto-correlation 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 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 x 50 km EMEP maps.

Flux-based ozone risk assessment for adult beech forests

Tropospheric ozone (O3) is a critical threat to forest ecosystems. A stomatal flux-based risk evaluation methodology at the leaf level was established recently in the context of the Convention on Long-Range Transboundary Air Pollution (LRTAP). This study demonstrates improvement and validation of the stomatal flux-effect approach for adult beech with results from the 8-year free-air O3 enrichment experiment at “Kranzberger Forst” (Germany). The risk assessment module of the SVAT model FO3REST, being under development for local scale O3-risk assessment of adult beech stands, was parameterized according to the LRTAP Convention’s Mapping Manual. Mean maximum stomatal conductance for water vapour of 245 mmol H2O m−2 PLA s−1, as suggested in the LRTAP Convention’s Mapping Manual for beech, was affirmed by assessment at “Kranzberger Forst”, resulting in 162 mmol O3 m−2 PLA s−1 upon recommended adjustment of the O3/water vapour diffusivity ratio to 0.663. Based on this ratio, a provisional corrected flux-effect function was deduced. Modelled Phytotoxic O3 Doses (POD 1) and potential O3-caused losses in biomass formation estimated with a site-specific stomatal conductance algorithm differed slightly only from estimates by the original LRTAP parameterisation. Analysis-derived POD 1 target value within the meaning of Article 2 of the European Council Directive 2008/50/EC of 10 mmol O3 m−2 corresponded to potential loss in biomass formation of about 10 % in ambient air relative to “pre-industrial” conditions. However, exceedance occurred by about a factor of two during the study period, indicating high risk at “Kranzberger Forst” under ambient air. Assessment for doubled O3 exposure indicated potential underestimation even of the O3 risk because modelled losses in biomass formation are in the lower range of the standard deviation of the observed ones.

Decline of Acid Rain Enhances Mercury Concentrations in Fish

M efforts have been made to reduce sulfur emissions in Europe. Acid rain pollution in Norway has diminished substantially, thanks to the 1979 Geneva Convention on Longrange Transboundary Air Pollution, which was implemented starting in 1983. Parallel with the reduction in acid rain, atmospheric concentrations and deposition of mercury (Hg) have also been reduced. Here, we show that reduced acid rain may have increased dissolved organic carbon in runoff, and enhanced transport of mercury from catchments, and increased in-lake Hg methylation. Together, these enhanced processes result in higher concentrations of methymercury in fish. Mercury pollution in Norway mainly originates from distant sources in other European countries. Similar to acid rain, the long-range atmospheric transport of Hg has declined significantly during the past decades. It was therefore unexpected when a recent nationwide survey showed strong increased Hg concentrations in brown trout (Salmo trutta) and European perch (Perca f luviatilis) in a representative set of lakes in southern Norway. We selected two of these lakes for further case studies based on the availability of historic lake chemistry data. The selection includes the lake with the highest Hgincrease in perch as well as one with a slight decline. The greatest health threat to human consumers comes from methyl-mercury (MeHg), a potent neurotoxin which is easily incorporated into living tissues. The methylation process is a key to the understanding of the potential danger posed by environmental Hg. Environmental Hg is methylated predominantly by naturally occurring bacteria known as sulfatereducing bacteria. The process occurs in saturated soils, anoxic lake waters, and in anoxic sediments, although the factors that control the methylation process are not fully understood. In October 2010 we sampled and analyzed modern sediments from two lakes in Norway (Figure 1).

Aerial Observations and Ground-based Measurements of Long-range Trans-boundary Air Pollution

Aerial Observations and Ground-based Measurements of Long-range Trans-boundary Air Pollution

Modelling of atmospheric nitrogen deposition effects to Polish terrestrial ecosystems for various emission scenarios until the target year 2020

Biogeochemical effects to Polish terrestrial ecosystems resulting from atmospheric nitrogen deposition were forecasted until the target year 2020. To this end recently updated critical loads of nutrient nitrogen were applied and the nitrogen deposition projections for the sequence of decades from 1980 until the target year 2020, based on the Current Legislation (CLE) and Maximum Feasible Reductions (MFR) emission scenarios. The predictions were done by use of the Very Simple Dynamic (VSD) Model developed within the Working Group on Effects of the UN ECE Convention on the Long-Range Transboundary Air Pollution CLRTAP. The calculations were done for three main forest ecosystems and three selected semi-natural ecosystems encompassing the whole territory of Poland with the spatial resolution defined by a grid cell of 1×1 km size. The study concluded with maps of CLnut(N) exceedances and expected nitrogen concentrations in soil as chemical criterion, assigned to different eutrophication risk categories for each deposition scenario. The obtained results show that in spite of the realistic (CLE scenario) and extreme (MFR) nitrogen emission reductions until 2020, more than 99% and 80% of total area of terrestrial ecosystems of Poland, respectively, will be exposed to excessive nitrogen deposition. Results of this study as well as studies done on the European scale reveal that the nitrogen emission reductions determined by the Gothenburg Protocol are still insufficient and may lead to negative ecological effects including loss of ecosystems biodiversity. This substantiates a demanding need for the revision of the CLRTAP Gothenburg Protocol.

Inciting protocols

This paper studies patenting decisions by firms in relation to the negotiation and signing of the Helsinki and Oslo protocol as part of the Convention on Long-Range Transboundary Air Pollution. We use a uniquely constructed patent data set on SO2 abatement technologies filed in 15 signatory and non-signatory countries in the period 1970–1997. The data distinguish between so-called ‘mother’ patents, or original inventions, and ‘family’ patents, which represent the same invention but are patents filed in foreign countries. Our analysis suggests that not only local environmental regulations matter for patenting decisions. International environmental agreements provide incentives for additional inventive activity in and the diffusion of knowledge towards signatory countries by reducing investment uncertainty for inventing firms.

Towards harmonization of forest deposition collectors - case study of comparing collector designs

In recent years the harmonization of methods in the frame of the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) operating under the UNECE Convention on Long-range Transboundary Air Pollution (CLRTAP) has been intensified. Among the C-actions of the FutMon project (LIFE07 ENV/D/000218; 2009-2010) the C1-Dep-22(SI) action was established with the goal to harmonize and develop the deposition monitoring procedures and sampling methods. The sampling equipment, spatial design of sampling plots and sampling frequency throughout Europe vary considerably. Therefore a step-by-step approach was made where the harmonized sampling equipment was developed and tested first. The selected collectors were installed at one observation plot of each participating country where measurements of throughfall and bulk deposition were run in parallel with the national collectors for a period of one year. To evaluate the agreement between methods, different statistical analyses were used including Altman-Bland plots, model II regression, and repeated measures ANOVA. Preliminary results from the “Intensive forest ecosystem monitoring plot” plot Brdo in NW Slovenia show a good agreement between national and harmonized bulk (both funnel-type) collectors, while comparison of throughfall measurements indicates systematic bias between harmonized (funnel-type) and national (gutter-type) collectors.

Cost-effective control of air quality and greenhouse gases in Europe: Modeling and policy applications

Environmental policies in Europe have successfully eliminated the most visible and immediate harmful effects of air pollution in the last decades. However, there is ample and robust scientific evidence that even at present rates Europe’s emissions to the atmosphere pose a significant threat to human health, ecosystems and the global climate, though in a less visible and immediate way. As many of the ‘low hanging fruits’ have been harvested by now, further action will place higher demands on economic resources, especially at a time when resources are strained by an economic crisis. In addition, interactions and interdependencies of the various measures could even lead to counter-productive outcomes of strategies if they are ignored. Integrated assessment models, such as the GAINS (Greenhouse gas – Air pollution Interactions and Synergies) model, have been developed to identify portfolios of measures that improve air quality and reduce greenhouse gas emissions at least cost. Such models bring together scientific knowledge and quality-controlled data on future socio-economic driving forces of emissions, on the technical and economic features of the available emission control options, on the chemical transformation and dispersion of pollutants in the atmosphere, and the resulting impacts on human health and the environment. The GAINS model and its predecessor have been used to inform the key negotiations on air pollution control agreements in Europe during the last two decades. This paper describes the methodological approach of the GAINS model and its components. It presents a recent policy analysis that explores the likely future development of emissions and air quality in Europe in the absence of further policy measures, and assesses the potential and costs for further environmental improvements. To inform the forthcoming negotiations on the revision of the Gothenburg Protocol of the Convention on Long-range Transboundary Air Pollution, the paper discusses the implications of alternative formulations of environmental policy targets on a cost-effective allocation of further mitigation measures.

Changes in the Chemistry of Small Irish lakes

A re-survey of acid-sensitive lakes in Ireland (initial survey 1997) was carried out during spring 2007 (n=60). Since 1997, atmospheric emissions of sulfur dioxide and deposition of non-marine sulfate (SO(4) (2-)) in Ireland have decreased by ~63 and 36%, respectively. Comparison of water chemistry between surveys showed significant decreases in the concentration of SO(4) (2-), non-marine SO(4) (2-), and non-marine base cations. In concert, alkalinity increased significantly; however, no change was observed in surface water pH and total aluminum. High inter-annual variability in sea salt inputs and increasing (albeit non-significant) dissolved organic carbon may have influenced the response of pH and total aluminum (as ~70% is organic aluminum). Despite their location on the western periphery of Europe, and dominant influence from Atlantic air masses, the repeat survey suggests that the chemistry of small Irish lakes has shown a significant response to reductions in air pollution driven primarily by the implementation of the Gothenburg Protocol under the UNECE Convention on Long-Range Transboundary Air Pollution.

Effect of operating condition on the particulate matter emission factor for a domestic biomass boiler

The effect of operating condition on the particulate matter emission factor for a domestic biomass boiler has been examined, with a view to improving emission inventories compiled under the Convention on Long-Range Transboundary Air Pollution (CLRTAP). It was found that the emission factor depended strongly on the boiler load, and that there were significant differences between the value used in current emission inventories and actual values found in a combustion installation from a typical domestic dwelling.

Mapping background values of atmospheric nitrogen total depositions in Germany based on EMEP deposition modelling and the European Moss Survey 2005

Abstract Background In order to map exceedances of critical atmospheric deposition loads for nitrogen (N) surface data on the atmospheric deposition of N compounds to terrestrial ecosystems are needed. Across Europe such information is provided by the international European Monitoring and Evaluation Programme (EMEP) in a resolution of 50 km by 50 km, relying on both emission data and measurement data on atmospheric depositions. The objective of the article at hand is on the improvement of the spatial resolution of the EMEP maps by combining them with data on the N concentration in mosses provided by the International Cooperative Programme on Effects of Air Pollution on Natural Vegetation and Crops (ICP Vegetation) of the United Nations Economic Commission for Europe (UNECE) Long-range Transboundary Air Pollution (LTRAP) Convention. Methods The map on atmospheric depositions of total N as modelled by EMEP was intersected with geostatistical surface estimations on the N concentration in mosses at a resolution of 5 km by 5 km. The medians of the N estimations in mosses were then calculated for each 50 km by 50 km grid cell. Both medians of moss estimations and corresponding modelled deposition values were ln-transformed and their relationship investigated and modelled by linear regression analysis. The regression equations were applied on the moss kriging estimates of the N concentration in mosses. The respective residuals were projected onto the centres of the EMEP grid cells and were mapped using variogram analysis and kriging procedures. Finally, the residual and the regression map were summed up to the map of total N deposition in terrestrial ecosystems throughout Europe. Results and discussion The regression analysis of the estimated N concentrations in mosses and the modelled EMEP depositions resulted in clear linear regression patterns with coefficients of determination of r 2 = 0.62 and Pearson correlations of r p = 0.79 and Spearman correlations of r s = 0.70, respectively. Regarding the German territory a nationwide mean of 18.1 kg/ha/a (standard deviation: 3.49 kg/ha/a) could be derived from the resulting map on total N deposition in a resolution of 5 km by 5 km. Recent updates of the modelled atmospheric deposition of N provided a similar estimate for Germany. Conclusions The linking of modelled EMEP data on the atmospheric depositions of total N and the accumulation of N in mosses allows to map the deposition of total N in a high resolution of 5 km by 5 km using empirical moss data. The mapping relies on the strong statistical relationship between both processes that are physically and chemically related to each other. The mapping approach thereby relies on available data that are both based on European wide harmonized methodologies. From an ecotoxicological point of view the linking of data on N depositions and those on N bioaccumulation can be considered a substantial progress.

Mapping atmospheric depositions of cadmium and lead in Germany based on EMEP deposition data and the European Moss Survey 2005

Abstract Background Every five years since 1990, the European Heavy Metals in Mosses Survey provided data on atmospheric heavy metal bioaccumulations in mosses throughout Europe at a high spatial resolution. The moss data show the effectiveness of air quality control policies: for Germany the metal bioaccumulations decreased between 1990 and 2000, whilst they increased from 2000 to 2005. This investigation is intended to show how the moss data could be used to map atmospheric depositions of Cd and Pb, which later on might serve for the calculation of Critical Loads Exceedances. In addition, we compared how much heavy metal concentrations in mosses in Germany deviate from background data observed in Greenland. Methods Mapping heavy metals with a high spatial resolution for the German territory was conducted according to the following methodology: EMEP deposition maps (50 km by 50 km spatial resolution) were intersected within a GIS with Kriging maps on Cd and Pb accumulations in mosses (EMEP (European Monitoring and Evaluation Programme) is a scientifically based and politically driven programme under the Convention on Long-range Transboundary Air Pollution for international co-operation to solve transboundary air pollution problems). Subsequently, the statistical relations between the EMEP modelled depositions and the bioaccumulations in mosses were quantified by using regression analysis. The regression functions were used to transform the moss concentration maps into deposition maps. The resulting maps on Cd and Pb depositions have a spatial resolution of 5 km by 5 km and were added to the respective map on the residuals of the regression functions (Regression Kriging). Finally, the territory of Germany was extracted from the European maps on Cd and Pb depositions and the legends were adjusted accordingly in terms of n standard deviations from the German mean value. The concentrations of Al, As, Cd, Cr, Cu, Mo, Pb, Sb, Sn, and Zn in the mosses sampled in 1990, 1995, 2000 and 2005 in Germany were compared with background values derived from mosses sampled in north-eastern Greenland (Zackenberg Background Values). The differences between heavy metal concentrations in mosses in Germany and Greenland were calculated for the 16 federal states of Germany and mapped for Pb. Results and discussion The regression models corroborate that the Cd concentration in mosses is correlated with the EMEP modelled total Cd deposition across Europe (regression coefficient according to Pearson, r p = 0.67; regression coefficient according to Spearman, r s = 0.69). The coefficient of determination is r 2 = 0.44. The same is true for Pb with r p = 0.76 and r s = 0.77 and r 2 = 0.58. Based on the regression models and the respective residuals, maps on the total deposition of Cd and Pb were calculated for the year 2005. The German mean value of total Cd and Pb deposition was 0.342 g/ha/a (standard deviation 0.08 g/ha/a and 8.6 g/ha/a (standard deviation 2.1 g/ha/a) respectively. The maps depict the spatial patterns of the total Cd and Pb deposition in terms of n standard deviations from the respective German wide mean value. The spatial resolution of the maps is 5 km × 5 km and reflects the mesh size of the moss monitoring net. Even today, the bioaccumulation of several metals in Germany still exceeds the background values observed in Greenland. This is true especially for Cd, Cr, Cu, Mo, Pb, Sb, Sn and Zn. Comparing the results of this investigation with those from other methods it can be concluded that the mean values calculated for the total Cd and Pb deposition for Germany differ from such assessed by deposition measurements and models. The latter are used to calculate Critical Loads Exceedances, which complement the ecotoxicological endpoint 'accumulation'. The deposition measurements in Germany are mainly based on monitoring systems conducted by the federal states. When trying to use deposition measurements from the ICP Forests level II programme for the validation of the EMEP deposition modelling, problems arose due to a lack of methodical harmonization and the quality of the depositions measurements. That is why in this investigation the quality controlled and spatially high resolved moss data were used to empirically validate EMEP modelled deposition maps. Conclusions In Germany, the moss measurement data provide a valuable tool at a high spatial resolution for the validation of modelling and mapping of atmospheric heavy metal deposition and should as such be used for this purpose. The comparison of the metal concentrations in mosses in Germany with the values found in Greenland indicate that atmospheric deposition of heavy metals in Germany is still considerably higher than the natural background deposition.