Erfassung der Anreicherung von Metallen und Stickstoff in baden-württembergischen Moosen

摘要

Background, aim, and scope Since 1990 the UN ECE Heavy Metals in Mosses Surveys provide data inventories of the atmospheric heavy metal bioaccumulation in mosses across Europe. In the 2005 survey the nitrogen accumulation was measured for the first time in most of the participating countries. In Germany, the surveys were conducted in close cooperation with the relevant authorities of both the Federal Republic and the sixteen states. Therefore, statistical evaluations of the moss survey data with regard to the whole German territory and single federal states are of interest. This article concentrates on the federal state Baden-Württemberg, dealing with the mapping of the spatiotemporal trends of metal accumulation from 1990 to 2005, the spatial patterns of nitrogen accumulation in 2005, and the spatial variability of bioaccumulation due to characteristics of the sampling sites and their surroundings. Furthermore, for the first time the relationship between the element concentrations in the mosses and Europe-wide modelled data on total depositions from the European Monitoring and Evaluation Programme (EMEP) on total depositions and were evaluated by means of correlation analysis using lead as an example. EMEP is a scientifically based programme under the Convention on Long-range Transboundary Air Pollution (CLRTAP) for international co-operation to model transboundary air pollution problems. Materials and methods In Baden-Württemberg the bioaccumulation of metal elements was determined mainly in Hypnum cupressiforme moss samples since 1990 and in 2005 also nitrogen was investigated according to a Europe-wide harmonised methodology. The according experimental protocol describes the selection of sampling sites and moss species, the chemical analysis and quality control and the dissemiation of the measured values for mapping spatial patterns. In Baden-Württemberg all sampling sites were described with regard to topographical and ecological characteristics and several criteria to be fulfilled according to the guideline. Together with the measurements this metadata was combined with other information regarding land use in the surroundings of the sampling sites in the WebGIS MossMet. The spatial structure of the metal bioaccumulation was analysed and modelled by variogram analyses and then mapped by applying different kriging techniques. Furthermore, multi metal indices (MMI) were derived for both the sampling sites and raster maps with help of percentile statistics: The MMI1990–2005 was calculated for As, Cd, Cr, Cu, Fe, Ni, Pb, Ti, V and Zn. The statistical association of the metal bioaccumulation, site specific characteristics as well as information on land use and emissions were analysed by bivariate nonparametric correlation analysis, contingency tables and Chisquare Automatic Interaction Detection (CHAID). Results The moss analyses show a statistically significant decrease of the bioaccumulation of most metal elements from 1990 till 2005. Only the Cr and Sb concentrations in the mosses increased from 2000 till 2005, however not statistically significant. Also the decline of the MMI from 2000 till 2005 is not statistically significant. The nitrogen concentrations in the mosses sampled in Baden-Württemberg range from 1.15 to 1.74?% and are negatively correlated with the tree height ( r s = 0.43, p r s = 0.3 to r s = 0.7 ( p r = 0.52, p Discussion For the first time it could be shown that element concentrations measured in mosses of Baden-Württemberg are associated with modelled total depositions of lead (EMEP). The strength of the statistical correlations was found to vary with time. The comparison of atmospheric depositions and element concentration in mosses should be repeated with measured deposition da