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Veröffentlichung Results of the second national forest soil inventory in Germany - Interpretation of level and stock profiles for PCDD/F and PCB in terms of vegetation and humus type(2018) Pandelova, Marchela; Bussian, Bernd M.; Henkelmann, BernhardPolychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated biphenyls (PCBs) were detected in 86 humic topsoil layers and in a subset of 11 randomly selected top mineral forest soils at the depths of 0-5 cm and 5-10 cm collected from different federal states of Germany. The distribution of these persistent organic pollutants (POPs) in humic topsoils with respect to vegetation cover (coniferous vs. deciduous vs. mixed), total organic carbon (TOC), altitude and latitude data was investigated. There is cross correlation between the contents and TOC while the correlation with latitude indicates higher abundances of POPs in central Germany where there is high population density accompanied with industrial activities. The calculated stocks suggest that humus type (mor, mull, or moder) in conjunction with forest type can explain the relative POPs abundances in different soil layers. Generally, humic topsoils show highest contents of POPs compare to the two mineral soils with a ratio of 100:10:1. However, the stock humic layers of coniferous stands contribute about 50% to the total stock, whereas at deciduous stands the stock is mainly located in the upper mineral soil layer (0-5 cm). The soil-water distribution coefficients (Kd) were calculated to estimate the potential translocation in the different soil types. The Kd values vary among the PCBs and PCDD/Fs congeners and are most variable for humic topsoils. There is pronounced chemical abundance in the top mineral soils with increasing Kd and this points to non-water bound transport processes for superlipophilic compounds. © 2017 Elsevier B.V. All rights reserved.Veröffentlichung Comparison of methods for the estimation of total inorganic nitrogen deposition to forests in Germany(2020) Ahrends, Bernd; Schmitz, Andreas; Geupel, Markus; Prescher, Anne-KatrinA reliable quantification of total inorganic nitrogen (TIN) deposition to forests is required for the evaluation of ecological effects of TIN inputs to forests and to monitor the success of clean-air policy. As direct measurements are scarce, different modeling approaches have been developed to estimate TIN deposition to forests. Three common methods are the (i) "canopy budget model," (ii) "inferential method," and (iii) "emission based estimates" using a chemical transport model. Previous studies have reported considerable and site-specific differences between these methods, complicating the interpretation of results. We use data from more than 100 German intensive forest monitoring sites over a period of 16 years for a cross-comparison of these approaches. Non-linear mixed-effect models were applied to evaluate how factors like meteorology, terrain and stand characteristics affect discrepancies between the model approaches. Taking into account the uncertainties in deposition estimates, there is a good agreement between the canopy budget and the inferential method when using semi-empirical correction factors for deposition velocity. Wet deposition estimates of the emission based approach were in good agreement with wet-only corrected bulk open field deposition measurements used by the other two approaches. High precipitation amounts partly explained remaining differences in wet deposition. Larger discrepancies were observed when dry deposition estimates are compared between the emissions based approach and the other two approaches, which appear to be related to a combination of meteorological conditions and tree species effects. © 2020 Ahrends, Schmitz, Prescher, Wehberg, Geupel, Andreae and Meesenburg