Anreicherung atmosphärischer Depositionen von Metallen und Stickstoff in Moosen Mecklenburg-Vorpommerns von 1990 bis 2005

Background, aim and scope Since 1990 the UN ECE Heavy Metals in Mosses Surveys provide data inventories of the atmospheric heavy metal bioaccumulation across Europe. In the survey 2005 the nitrogen accumulation was measured for the first time in most of the participating countries. In Germany, the surveys were conducted in close cooperation of 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 Mecklenburg-Western Pomerania, 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. Materials and methods The bioaccumulation of up to 40 trace elements in mosses was determined according to a Europe-wide harmonised methodology. The according experimental protocol regulates the selection of sampling sites and moss species, the chemical analysis and quality control and the classification of the measured values for mapping spatial patterns. In Mecklenburg-Western Pomerania 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 MMI_1990–2005 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 was analysed by bivariate nonparametric correlation analysis, contingency tables and Chi-square Automatic Interaction Detection (CHAID). Results The results of the quality controlled chemical analyses show a significant decrease of the metal bioaccumulation in Germany from 1990 to 2000 for all elements. However, in Mecklenburg-Western Pomerania the concentrations of Cr and Zn are even significantly higher than those found in 1990. From 2000 to 2005?a further non-significant increase can be stated for As, Cu, Ni and Ti. The concentrations of Cd and Pb decreased significantly throughout all four surveys. The MMI illustrates the temporal trend of the metal bioaccumulation as a whole: After a significant decrease from 1990 to 2000 it increased significantly till 2005. The N concentration in mosses in Mecklenburg-Western Pomerania reaches from 1.3 to 2.3?% in dry mass and is negatively correlated with the forest ratio in the surroundings of the moss sampling sites and to the same degree positively correlated with the area ratio of agricultural land uses. Except for Cd, Pb and Sb all metal concentrations in the mosses are negatively correlated with the forest ratio around the sampling sites. With the exception of Cr all metal concentrations are further negatively correlated with the precipitation sums of the accumulation periods. Only the Cu and Zn concentrations show no or rather a negative correlation with the tree height whereas all other elements exhibit positive correlations. Furthermore, all elements except Cr are significantly associated to the sampled moss species, the growth pattern and the frequency of occurrence of the mosses at the respective sampling sites. Exemplified for Cu multivariate correlations were furthermore detected by CHAID. It could be shown that the frequency of the mosses, the sampled moss species, the distance to motorways and the distance to the Baltic Sea are the statistically most significant boundary conditions of the Cu concentrations in the mosses sampled in Mecklenburg-Western Pomerania in 2005. No correlations were found between the modelled total depositions and the concentrations of Cd, Hg and Pb in the mosses at p < 0.1. For Pb in 1995?r is 0.52 at p = 0.012, for the other surveys no correlations at p < 0.05 could be found. Discussion The increase of the Cr bioaccumulation from 2000 till 2005 is particularly pronounced in Mecklenburg-Western Pomerania. This trend is confirmed with regional differences in the national average as well as in other participating countries like in Switzerland. Deposition measurements did not register this trend. In contrast to the UNECE area, the federal territory and several federal states no correlations were found between the modelled total depositions and the metal concentrations in the mosses. Conclusions The fact that no correlations were found between the modelled total depositions and the element concentrations in the mosses may be caused by the low spatial resolution (50?×?50?km) of the EMEP data. The moss surveys contribute to the heavy metal and the multi-component-model of CLRTAP because they prove on different spatial scales how air pollution control influences the accumulation of emitted substances in environmental subjects of protection like vegetation. In contrast to deposition measurement networks the moss monitoring identified a trend reversal in Mecklenburg-Western Pomerania: The continuous decrease of the metal bioaccumulation in mosses from 1990 till 2000 has changed to an increase of several metals between 2000 and 2005. This increase is significant for Cr and Zn. Recommendations and perspectives The spatial resolution of the EMEP deposition data should be enhanced based on the Europe-wide regression relationship between the element concentrations in the deposition and in the mosses. For regional studies the existing but so far not useable deposition measurement data of the federal states should be made available. It should further be investigated what caused the increase of the Cr concentrations above the level of 1990 – perhaps emissions or biogenic effects as a consequence of simultaneously increased nitrogen loads? The Heavy Metals in Mosses Surveys are a positive example for environmental monitoring activities reaching across three spatial and administrative levels: regional (e.?g. federal state or natural landscape), nation wide (e.?g. Germany) and continental (e.?g. Europe). In Germany the harmonised and quality controlled moss data are made available via a WebGIS portal. Therefore the moss data may easily be accessed for environmental monitoring purposes and the control of environmental political actions. Hence, the continuous task of environmental monitoring can be met and carried on in the future. It should further be considered to expand the moss monitoring on the survey of persistent organic pollutants and apply it in human-biomonitoring. This would facilitate the acquisition of indoor and outdoor pollution with the same receptor.     

Evaluation of numerical simulations of CO2 transport in a city block with field measurements

Studying urban air-transport phenomena is highly complex, because of the heterogenous flow patterns that can arise. The main reason for these is the variable topology of urban areas, however, there is a large number of influencing variables such as meteorological conditions (e.g., wind situation, temperature) and anthropogenic factors such as traffic emissions. During a one-year CO₂ measurement campaign in the city of Basel, Switzerland, steep CO₂ gradients were measured around a large building. The concentration differences showed a strong dependency on the local flow regimes. Analysis of the field data alone did not provide a complete explanation for the mechanisms underlying the observed phenomena. The key numerical parameters were defined and the influence of turbulent kinetic energy dependency on the time interval for the Reynolds decomposition was studied. A Reynolds-Average Navier-Stokes Computational Fluid Dynamics (CFD) approach was applied in the study area and the CO₂ concentrations were simulated for six significant meteorological situations and compared to the measured data. Two flow regimes dependent on the wind situation, which either enhanced or suppressed the concentration of CO₂ in the street canyon, were identified. The enhancement of CO₂ in the street canyon led to a large difference in CO₂ concentration between the backyard- and street-sides of a building forming the one wall of the canyon. The specific characteristics of the flow patterns led to the identification of the processes determining the observed differences in CO₂ concentrations. The combined analysis of measurement and modeling showed the importance of reliable field measurements and CFD simulations with a high spatial resolution to assess transport mechanisms in urban areas.     

?kotoxikologie soll endlich wissenschaftliches Fach werden

Ohne Zusammenfassung     

Bioethics of fish production: Energy and the environment

Aquatic ecosystems are vital to the structure and function of all environments on earth. Worldwide, approximately 95 million metric tons of fishery products are harvested from marine and freshwater habitats. A major problem in fisheries around the world is the bioethics of overfishing. A wide range of management techniques exists for fishery, managers and policy-makers to improve fishery production in the future. The best approach to limit overfishing is to have an effective, federally regulated fishery, based on environmental standards and fishery carrying capacity. Soon, overfishing is more likely to cause fish scarcity than fossil fuel shortages and high energy prices for fish harvesting. However, oil and other fuel shortages are projected to influence future fishery policies and the productive capacity of the fishery industry. Overall, small-scale fishing systems are more energy efficient than large-scale systems. Aquaculture is not the solution to wild fishery production. The energy input/output ratio of aquacultural fish is much higher than that of the harvest of wild populations. In addition, the energy ratios for aquaculture systems are higher than those for most livestock systems.     

HYDRAULIC FRICTION LOSS IN SMALL DIAMETER PLASTIC PIPELINES1

ABSTRACT: Although estimation of hydraulic friction loss in pipelines is one of the most frequent routine computations made by water supply engineers, almost no post-construction analysis of the accuracy of these calculations exists in the literature. This paper reports the field measured friction losses in three one-mile sections of small diameter pvc pipe which had been in service for 10 years. Hazen-Williams and Darcy-Weisbach equations are examined to provide a framework for comparing Hazen-Williams coefficients recommended by pipe manufacturers to those obtained by the field measurements. The conclusion is that the C_HW factor of 150 recommended by most pvc pipe manufacturers is too high for the diameter-velocity combinations encountered in rural dead-end small diameter lines. The measured coefficients averaged 133 which is close to that predicted by superimposing Hazen Williams coefficients on the Moody diagram from which the friction factor for the Darcy-Weisbach equation is obtained.     

Relevance of BFRs and thermal conditions on the formation pathways of brominated and brominated-chlorinated dibenzodioxins and dibenzofurans

The widespread use of brominated flame-retarded products in the last two decades has resulted in an increasing presence of bromine in thermal processes such as waste combustion and accidental fires. Brominated and brominated-chlorinated dibenzodioxins and dibenzofurans (PBDDs/PBDFs, PXDDs/PXDFs) are micropollutants of concern arising from such processes. The present review aims to evaluate the relevance of these compound classes in actual thermal processes. Four categories of thermal processes are discussed in this respect according to their potential for PBDD/PBDF and PXDD/PXDF generation: thermal stress, pyrolysis/gasification, insufficient combustion conditions and controlled combustion conditions. Under thermal stress situations, as they may occur in production or recycling processes, PBDDs/PBDFs precursors like polybrominated diphenylethers (PBDE) can have a relevant potential for PBDD/PBDF formation via a simple elimination. Under insufficient combustion conditions as they are present in, e.g. accidental fires and uncontrolled burning as well as gasification/pyrolysis processes, considerable amounts of PBDDs/PBDFs can be formed from BFRs, preferably via the precursor pathway. In contrast, under controlled combustion conditions, BFRs and PBDDs/PBDFs can be destroyed with high efficiency. The relevance of de novo synthesis of PXDDs/PXDFs is discussed for this condition.Providing a basis for the understanding of PXDD/PXDF formation in actual thermal processes, the present paper also summarises the formation pathways of brominated and brominated-chlorinated PXDDs/PXDFs from brominated flame retardants (BFRs) investigated during laboratory thermolysis experiments. Relevant mechanistic steps for PBDD/PBDF formation from brominated precursors are discussed including elimination reactions, condensation steps and debromination/hydrogenation reactions.In addition, chlorination/bromination and halogen exchange reactions are briefly discussed with respect for their relevance on the final distribution of PBDDs/PBDFs, mixed chlorinated PXDDs/PXDFs and PCDDs/PCDFs resulting from thermal processes.     

Assessment of the Ecological Integrity of Traunsee (Austria) Via Analysis of Sediments and Benthic Microbial Communities

Since nearly one hundred years Traunsee experiences the import of tons of liquid and solid waste originating from salt and soda production. Today, the lake exhibits chloride concentrations of up to 170 mg L^-1 and 19% of the lake floor are directly or indirectly influenced by industrial deposits (ID). Based on the comparison of several microbial parameters in unaffected, directly affected and intermediate lake bottom sediments, the ecological integrity of the lake was evaluated. The highly alkaline ID, which were exclusively colonized by microorganisms, harbored a bacterial community reduced by a factor of 10 in abundance and biomass compared to undisturbed sediment areas within the lake. The bacterial community of ID was furthermore characterized by a reduced content of actively respiring cells (INT-formazan reduction), a lower frequency of dividing cells (FDC) and a significantly reduced cell and biomass production. A 80 to 90% reduction in carbon recycling is estimated for the area exclusively covered by ID. Protists, although occasionally absent from the industrial sediments, were in general found to be less sensitive to the contaminant stress. Differences in alkalinity and dissolved organic carbon (DOC) concentrations of sediment porewaters as well as the total organic content and C/N ratios of sediments partly explain the microbial pattern observed at the various sampling sites. Possible consequences of the continuous industrial tailings for the whole lake ecosystem and the validation of the ecological integrity are discussed.     

Obituary

Water, Air, &; Soil Pollution: Focus -     

Operator-centred local error management in air traffic control

Introduction: A large number of air traffic control occurrences take place without resulting in loss of separation between aircraft. Unfortunately such occurrences are seldom reported and therefore not used for disclosing system weaknesses, such as inappropriate methods and procedures.The ATCC (Air Traffic Control Centre) Malmoe made a trial with local reporting of “learning occurrences”. The trial was ATCO-(Air Traffic Controller) centred. The study objectives were to evaluate if ATCOs would start to report after a defined training and marketing effort, if they could identify system weaknesses, if concrete actions for safety improvement would be taken as a result of the trial and to what extent expert support was necessary.Method and material: The trial period was eight months. The ATCO report would be made on a simple form, available on site. These reports would then be analysed in groups and the marketing and feedback efforts would be co-ordinated by the local flight safety group.Results: 43 reports were filed and analysed during the trial period. The initial motivational training and marketing was considered adequate. During the group discussions, the ATCOs identified system weaknesses within 40 of the reports. The resulting safety improvement actions included: the ATCC unit becoming more active in contacting the pilots and airline companies, the renaming of some waypoints (due to name similarities), the implementation of safer procedures when relieving ATCOs, the training of ATCOs in cockpit flight management systems, and the initiation of a research project primarily concerned with ATCO mental overload.Expert support was required in the beginning to help ATCOs focus on the system rather than on the individual.