Großräumige Regionalisierung der Kohlenstoffbindung in Wäldern Nordrhein-Westfalens

Background, aim and scope The United Nations Framework Convention on Climate Change understands carbon fixation in forests as an important contribution for the reduction of atmospheric pollution in terms of greenhouse gases. According to the German forest inventory on carbon in biomass an amount of 191?t C/ha was roughly estimated, without any spatial differentiation. Therefore, the aim of this investigation was to statistically identify factors that are significant for the carbon fixation and to map the spatial patterns of C sequestration in the federal state North Rhine-Westphalia. Materials and methods Together with information on climate, elevation, vegetation, and deposition, data from two forest monitoring networks were analysed statistically. Geostatistics and the decision tree algorithms Classification and Regression Trees (CART) and Chi-Square Automatic Interaction Detection (CHAID) were applied to calculate surface maps from punctual data on C in vegetation, in dead wood and in soil. Whereas spatial autocorrelation could be detected for the C loads in the humus layers, no surface maps could be calculated for the C contents of the mineral soils and for the forest trees/dead wood. Here, CART and CHAID were used to derive decision trees that were applied on available surface data to predict C loads for the entire study area. Results About 19?t C/ha could be predicted for the humus layer, 67?t C/ha for forest trees/dead wood and 90.7?t C/ha for the soil. An overall mean of 177?t C/ha was calculated for North Rhine-Westphalia lying 14?t C/ha below the German wide mean. Discussion Compared to the calculated results in another investigation a total of 68?mio. t C for the above ground dendromass was estimated. This is 11?mio. t C/ha higher than the amount calculated in this study and may be due to the fact that this value includes the C-pools in both, the brushwood and herbaceous layer in their estimations. The average C concentration in the humus layer all over Germany was found to amount for 20.7?t C/ha which is slightly above the C storage calculated for North Rhine-Westphalia. In the same study a Germany wide C average of 87.9?t C/ha was calculated which is very close to the 90.7?t C/ha calculated in this study. Conclusions The surface estimations of the C-pools in the above-ground biomass, the humus layer and the mineral soil enable to map the efficiency of the C-bounding capacity regarding the fixation of the greenhouse gas CO₂. The mean values derived in this study are in good accordance with estimations based on other techniques. Recommendations and perspectives The approach presented should be verified by application to Germany wide inventory data and by means of Regression Kriging. Furthermore, the C-fixation under climate change should be calculated by combining statistical methods and the dynamic modelling tool WASMOD.     

REP-LECOTOX: an example of FP 6 INCO project to strengthen ecotoxicological research in WBC (Western Balkan countries)

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.     

Konzentrationen von Schwermetallen in Bodenlösungen aus bayerischen Wäldern

Goal and Methods

During two years, soil solution samples were collected at 18 forest sites with low anthropogenic heavy metal loads in Bavaria using ceramic suction cups. The collected samples were analysed for pH, conductivity, dissolved organic compounds, and the trace elements Al, Cr, Fe, Mn, Ni, Cu, Zn, Cd, Ba, and Pb.

Results

In addition to initial interference effects caused by the installation of suctions cups, time series were characterised by seasonal variations. The results obtained for the replicated suction cups were comparable for every individual area with standard deviations of 20 to 25 percent. With increasing soil depth, the pH of the soil solution increases specifically at those sites (up to 2.5 pH units) where the topsoils have been acidified. On the other hand, concentrations of all trace elements investigated — excepted of Al and Mn — are not influenced by the soil depth. The forest stand has no significant additional effect on trace element concentrations. Contents of Al, Mn, and Zn are correlated with low pH-values in the soil solution, whereas the mobilisation of Ba is mainly caused by ion exchange. Complexes of trace elements and dissolved organic matter were only detected for Cu at one site. Element concentrations in the soil solution are not significantly influenced by the contents of aqua regia soluble portions in the soil matter. Only very high qua soluble portions increase the concentrations in the soil solution. The overall heavy metal concentrations determined in soil solutions are low compared with different limiting and threshold values, respectively.

Conclusions

Trace element concentrations in soil solutions are mainly influenced by the soil properties themselves. The contribution of the forest stand is negligible. Therefore, from the ecotoxicologic point of view, the risk of leaching heavy metals contaminating the groundwater is not significant for the investigated forest sites and without any respect to silviculture practices.     

Schwermetalle in Regenwürmern Baden-Württembergs

Goal and Scope

Since 1984 the Environmental Protection Agency (LfU) of the State of Baden-Wuerttemberg has been investigating the heavy metal burden of earthworms from representative long-term forest observation plots. These investigations are aimed at elucidating and assessing adverse effects of pollutants on the soil biocenosis.

Methods

At first only lead and cadmium were measured in the worms; in repetitive measurements over the years further metals or metalloid elements such as aluminum, arsenic, chromium, cobalt, copper, manganese, mercury, nickel, thallium, vanadium, and zinc were added to the agenda.

Results and Conclusion

The frequency distribution of the metals in the earthworms was characterized statistically. For the first time state-wide background values, normal values and threshold values were established for all the elements measured. A comparable study with a similar range of parameters is known neither nationally nor internationally. Time trend studies have been available for lead and cadmium since 1985/86, and for zinc since 1987. The studies show a steady decrease of the heavy metals on a state-wide average and especially in the ‘Odenwald’ and ‘Black Forest’ hills with their formerly highly polluted earthworm habitats. Today, the level of these metals in the earthworms is low with few exceptions. This holds true for other heavy metals as well.

Recommendations and Perspectives

The state-wide decreasing very low heavy metal burden of forest observation plots far from known emission sources can be considered a success of air pollution abatement measures. Because of the ongoing atmospheric deposition of heavy metals, regular observation should continue in order to estimate time trends and to recommend the reduction of emissions when precautionary values (part 2) are exceeded.     

Elbehochwasser 2002 — Ein Rückblick

Objective

Flood sediments were investigated due to the extreme flood situation around Dresden in August 2002

Method

The samples have been analyzed by screening inorganic and organic pollutants.

Results

It was observed that As, Pb, Cd, Zn, Cu, B and other heavy metals as well as DDT, PCB and Benzo [a] pyren were significantly enriched.

Conclusion

Depending on geogenic and anthropogenic impacts, the spatial distribution of these contaminants was different. Organic compounds were dislocated down stream from Czech Republic along the Elbe River. Because of the old ore mining, samples near the Mulde and Wei\eritz Rivers showed high metal pollution.

Perspective

More detailed and systematic investigations should be undertaken in the Elbe and Mulde river systems.     

Mangrove forest structure and productivity in the Fly River estuary,Papua New Guinea

In April, July and August 1989 and February 1990, the delta region of the Fly River was surveyed to establish the aerial extent of mangrove forests, their species composition, tree densities and basal areas, and potential net primary production. Mangrove forests cover 87 400 ha, mainly on islands within the delta. Twentynine mangrove plant species were recorded, but there were only three major forest types in the delta.Rhizophora apiculata-Bruguiera parviflora forests (hereafterRhizophora-Bruguiera forests) predominated in regions where river water salinities were >10. These forests covered 31 500 ha and had mean total tree densities and basal areas of 2027 stems ha^–1 and 21 m² ha^–1, respectively. Forests of the palmNypa fruticans (hereafterNypa forests) covered 38 400 ha, mainly in regions where river salinities were ~1 to 10, and had mean total densities and basal areas of 4431 stems ha^–1 and 38 m² ha^–1, respectively. Forests dominated byAvicennia marina and/orSonneratia lanceolata (hereafterAvicennia-Sonneratia forests) predominated on accreting banks of sediment and covered 17 500 ha. In very low-salinity (< 1) regions there are large monospecific stands ofS. lanceolata. Mean total densities and basal areas forAvicennia-Sonneratia forests were 7036 stems ha^–1 and 22 m² ha^–1, respectively. Mean net primary productivity (kg C ha^–1 d^–1) was estimated to be 26.7, 27.1 and 19.0 forRhizophora-Bruguiera, Nypa andAvicennia-Sonneratia forests, respectively. Total daily net primary production by all mangrove forests was estimated at 2214 t carbon. Using assumptions based on work in tropical Australia, it was estimated that ~678 t carbon (or 31% of primary production) were exported daily from mangrove forests to the waters of the delta.Contribution No. 550 from the Australian Institute of Marine Science     

Chlorcarbazole in Böden

Goal and Scope

In soil samples taken from several locations throughout Bavaria, the detection of p,p′-DDT by GC/MS was impeded by a superimposed peak. The authenticity of this compound, which has been identified as dichlorocarbazole by mass spectra databases, is confirmed and some characteristics of its occurrence in soils are described.

Methods

The authenticity of the unknown compound has been checked by comparing the low resolution mass spectra and chromatographic retention times with those of standard compounds. Some methodical studies concerning extraction and clean-up were also carried out.

Results and Conclusion

Mass spectra and retention of the unknown compound are identical with that of the 3,6-dichlorocarbazole standard compound; additionally, a second chlorocarbazole was found with mass spectrum and retention similar to 3-chlorocarbazole. In many topsoils (A-horizons) and subsoils (B-horizons) from 200 locations of different land-uses, the dichlorocarbazole could be detected. In contrast to PAH and other POPs, maximum concentrations occurred in the A- and upper B-horizons of forest soils rather than in the organic layers. Assuming the environmental distribution properties of the chlorocarbazoles to be similar to those of the PAH, this could indicate that the chlorocarbazoles are not deposited from the atmosphere as a result of anthropogenic activities but might be generated by natural processes in situ.

Recommendation and Perspective

To our knowledge, the occurrence of chlorocarbazoles in soils of unpolluted sites has not been previously described. Their widespread occurrence in relatively high concentrations and their detection using analytical standard procedures is surprising and requires further examination.     

Schwermetalle in Regenwürmern Baden-Württembergs

Goal and Scope

The heavy metal burden of the soil and of earthworms from representative long-term forest observation plots has been measured since 1984 as one component of the media-embracing environmental monitoring network of the State of Baden-Wuerttemberg. These investigations are aimed at elucidating and assessing adverse effects of pollutants on the soil biocenosis

Methods

So-called characteristic curves for the metals Cd, Cu, Ni, Pb, and Zn were developed for the assessment. Earthworm toxicity data and background values in soil served as criteria. This procedure facilitates a comparative assessment of different pollutants. The mobility of the metals, which greatly influences their bioavailability and toxicity, was taken into account for the effects assessment.

Results and Conclusion

Besides inventorying the heavy metals (Part 1), the question of threshold values for toxic reactions as well as for accumulation was raised. The metal concentrations were assessed in the soil with regard to its habitat function. The ecotoxicological assessment revealed that the heavy metal burden of the investigated plots lies within the background- or precautionary range, well below the screening value established here to indicate the effect threshold in earthworms. This result means that a pollution of the forest observation plots with the metals cadmium, copper, lead, nickel, and zinc is low or absent. Only the distribution of the lead content is centered slightly above background (but clearly below the toxicity threshold). This slight lead burden of the soil of the observation plots can be explained by emissions from motor vehicles. Investigations at sites that are contaminated with either chromium or copper or cadmium showed that an accumulation of these metals in the body of the worms can be observed only above a threshold concentration of several hundred micrograms of mobile metal per kilogram in the upper layer of the soil.

Recommendations and Perspectives

The hitherto unknown threshold values for the accumulation in the body of the earthworm should be statistically validated and extended to other elements. Further research is needed in order to build a well founded basis for the ecotoxicological assessment of soil pollution. Acute and chronic earthworm effect thresholds are neither available yet for arsenic, cobalt, and mercury nor for some other elements occurring less frequently as soil pollutants. Background values depending on the kind of rock have been measured so far for total chromium only. They are lacking for the more toxic chromium (VI) which is a frequent soil pollutant but naturally occurs in traces only.     

Ansätze zur regionalen Quantifizierung von Methan aus Pflanzen

Background

Methane as a gas influencing our climate is of high importance according to the Kyoto-Protocol. The more precisely we can determine anthropogenic and biogenic sources, the more effective measures we can take to reduce the gas. Direct emission of methane from plants apparently contributes significantly to the total emission but has not been accounted for in emission balances until now.

Methods

A model was created to calculate methane emission for a short time period in regional resolution for Lower Austria and to relate the results to known literature.

Results and Discussion

First model results suggest that the amount of methane released from plants in relation to emissions from other known sources are of importance.

Perspectives

The uncertainties associated with both measurements and quantification require reduction by further research.     

Nitrate uptake in marine phytoplankton: Energy sources and the interaction with carbon fixation

Field studies of whole natural phytoplankton communities from Knight Inlet, B. C., Canada and laboratory cultures of the diatom Skeletonema costatum indicate inorganic carbon fixation may be temporarily suppressed following 10 to 15% enrichment with NO ₃ ^- or NH ₄ ⁺ . (This effect is suggested to be due to competition between inorganic carbon and nitrogen for adenosine triphosphate (ATP), and is reduced when chlorophyll a is increased intracellularly after 6 to 8 h.) Results imply that the source of ATP for nitrate uptake is primarily from Photosystem I (cyclic photophosphorylation) in the presence of light. It would appear that a transient nutrient-adaptive response occurs upon addition of extracellular nitrogen.     

Biomonitoring von Stickstoffimmissionen

Background and aim

Air pollution caused by oxidized and reduced nitrogen is distributed over wide areas of Europe at a high level. As an alternative or complement to physical measurements and modelling calculations, biomonitoring with plants provides techniques to assess amounts and effects of pollution from oxidized and reduced nitrogen compounds (depositions and concentrations). Many of the previously implemented techniques are based on well-proven standardised methods, e.g. documented in VDI guidelines, modified more or less for a biomonitoring of atmospheric nitrogen pollution. This paper gives a review of the techniques for a biomonitoring of atmospheric nitrogen pollution, their possibilities as well as their limitations.

Main features

-diversity of the ground vegetation

-nitrogen accumulation in vascular plants

-exposure of vascular plants

-mapping of epiphytic lichens, bryophytes and algae

-nitrogen accumulation in lichens and bryophytes

-exposure of lichens and bryophytes

Results and Discussion

Important response parameters are nitrogen concentrations in plant tissue (shoot, needle, leave) and biodiversity of plant species. These responses of vascular plants in many cases are influenced by other local varying conditions, in particular the soil. The exposure of vascular plants over a short period provides a standardised quantification of the total atmospheric nitrogen input in a model ecosystem. The enrichment of nitrogen in the plant tissue of bryophytes and lichens from the ground vegetation is closely correlated with the amount of nitrogen deposition. The diversity of epiphytic lichens and the response of exposed Hypogymnia physodes is more sensitive to ammonia than to nitrous oxide, whereas with the diversity of epiphytic bryophytes or the abundance of algae no significant correlation with atmospheric N pollution were found.

Conclusions

Some bioindication techniques provide a causeeffect related, partly standardised biomonitoring of nitrogen pollution. In some cases varying experiences with some biomonitors like the biodiversity of the ground vegetation, exposure of lichens, moss bags and grass cultures stress the need for more research in this subject.     

Ökotoxikologische Wirkungen von Teeröl-imprägnierten Holzpfählen

Aim and Scope

This study was aimed at evaluating environmental effects of tar-oil impregnated (tanalized) tree stakes using simple and efficient biotests to obtain results of its ecological impacts during the tar-oil breakdown in the stake.

Results

1. Soil respiration was measured in-situ as an indication of soil microbial activity in two field trials. Soil respiration was measured in a 20 year-old apple orchard at various distances from the tar-oil impregnated tree stakes and also on soil mixed with chippings from pine stakes with tar-oil impregnation of different ages.
2. Cress germination tests were employed to evaluate tar-oil phytotoxicity in a field and laboratory trial. Cress was seeded close to tree stakes in the same 20 year-old apple orchard and germination rates related to tar oil-impregnation. Cress was also seeded in trays in sand mixed with pine chippings from stakes with tar-oil impregnation of different ages.
3. The portion of the carcinogenic benzoapyrene (BaP) ranged between 0.0015% in freshly tar-oil impregnated to 0.4% in tar-oil impregnated 20-year old trees stakes, i.e. irrespective of the overall PAK concentration and its degradation.
4. Kinetic analysis using DIXON plots showed a 50% breakdown of overall PAHs after ca. 2.7 years, i.e. km or Ki values of less than 3 years.

Conclusion

Germination tests of cress and endogenous seeds as well as soil respiration proved sensible indicators of the phytotoxicity and ecotoxicity of tar-oil impregnated tree stakes in fruit orchards. Soil respiration proved particularly sensitive to tar-oil ageing. Its combination with kinetic inhibition models resulted in parameters suitable for the interpretation of results.     

Einsatz der Hassediagrammtechnik zum Vergleich von Bergbaubetrieben unter dem Aspekt der Nachhaltigkeit

Ziel und Hintergrund

Der Vergleich von Bergwerken unter dem Gesichtspunkt einer nachhaltigen Entwicklung erfordert die Berücksichtigung einer Vielzahl von Kriterien die gleichermaßen ökonomische, ökologische und soziale Aspekte berücksichtigen. Bergwerksbetreiber stehen bei ihren strategischen und operativen Entscheidungen vor der Schwierigkeit diese Kriterien angemessen zu berücksichtigen. Durch den Einsatz, der HDT wird die Komplexität der Entscheidungssituation reduziert. Sie unterstützt die Aufbereitung der verfügbaren Informationen und erleichtert so die Entscheidungsfindung.

Methodik

Das Ziel einer nachhaltigen Entwicklung im Bergbau kann durch den Einsatz von Indikatoren konkretisiert werden. Im Rahmen dieser Arbeit erfolgt ein Vergleich ausgewählter Bergwerke durch die Definition geeigneter Indikatoren, ihre numerische Belegung und durch ihre Verwendung in der HDT. Dabei werden verschiedene methodische Aspekte wie die Klassifizierung von Daten, deren Aggregierung und Gewichtung sowie die Einbeziehung von Expertenwissen dargestellt.

Ergebnisse

Am Beispiel ausgewählter Bergwerke wird gezeigt, dass eine Sortierung der Bergwerke anhand ihrer charakteristischen und als wesentlich erachteten Eigenschaften möglich ist. Durch den Einsatz der Hassediagrammtechnik wird die Komplexität der Entscheidungssituation reduziert. Es wird aber auch deutlich, dass mit diesem Instrument kein Verfahren vorliegt, dessen Einsatz automatisch zu einer eindeutigen Rangfolge führt. Es bleibt notwendig, die Anwendung der Hassediagrammtechnik in einen umfassen deren Entscheidungs-und Zielfindungsprozess zu integrieren.

Diskussion

Die Sortierung erfolgt bewertend, d.h. sie nutzt aus, dass charakteristischen Eigenschaften von Bergwerken inhärent eine Orientierung nach ?gut’ und ?schlecht’, zugeordnet werden kann. Es wird aber auch deutlich, dass mit diesem Instrument kein Verfahren vorliegt, dessen Einsatz, automatisch zu einer eindeutigen Rangfolge führt.

Schlussfolgerungen

Es bleibt notwendig, die Anwendung der Hassediagrammtechnik in einen umfassenderen Entscheidungs- und Zielfindungsprozess zu integrieren. Vorschläge zu einer Erweiterung der Hassediagrammtechnik werden formuliert.

Empfehlungen und Perspektiven

Die Hassediagrammtechnik versteht sich als eine Bewertungsmethodik, die das in der Nachhaltigkeits-/Bewertungsdiskussion so gefürchtete Vergleichen von ?Äpfeln mit Birnen’ vermeidet. Als relativ neue Methode, die sich als Alternative zu etablierten Bewertungsverfahren sieht, lässt sich weiterer Forschungsbedan ableiten.     

Die externen Kosten der Stromerzeugung aus erneuerbaren Energien im Vergleich zur fossilen Stromerzeugung

Aim and Background

The supply and use of energy is related to environmental impacts, which cause significant economic damage. As these costs are not reflected in the price of energy, there is little incentive for the polluter to reduce the pressure on the environment. From an economic point of view, environmental resources and services are used beyond the optimal level. The quantification of external costs has been an area of intensive research, in particular within the series of ExternE projects funded by the European Commission. Although external cost estimates have been successfully used to support European environmental legislation, the assessment of external costs is still a matter of significant uncertainties — in particular in areas were potential large environmental impacts are expected. In spite of uncertainty and limited knowledge, policy needs to require guidelines for the evaluation of energy and environmental policy measures.

Main Features

Based on a critical review of the current literature, recommendations for the quantification of external costs from renewable electricity generation in comparison to fossil nuclear technologies are derived.

Results and Discussion

Current electricity market prices do not reflect the total costs of electricity generation. Quantifiable external costs from fossil electricity generation are in the same order as private generation costs. The internalisation of external costs will improve the competitiveness of renewable energy technologies. To avoid market distortion, policy shall implement framing conditions supporting the further internalisation of external costs.

Conclusions

Costs for supporting renewable energy via the German feed-in tariffs are compensated for by external costs avoided.

Perspectives

Fossil and nuclear energies are more expensive than is teflected by economical quantification. In contrast, the costs for renewable energies tell the truth even today. The sooner the external costs are integrated in the pricing, the sooner the relaunch of energy supply will attract interest, also from the economic point of view.     

Homologue distribution patterns of 2,3,7,8-chloro-substituted PCDD/F in Bavarian soils

Background

Soil-background values of PCDD/F concentrations are usually conveniently displayed as toxic equivalent (TEq), being a bulk parameter of all relevant 7 PCDD- and 10 PCDF-congeneres, chloro-subsidized at the 2nd, 3rd, 7th and 8th carbon atom. Data here are ample, not so survey on congenere/homologue patterns occurring in soils. The sufficient number of samples taken within this analysis allowed first a well-grounded evaluation.

Results

OCDD proved to be the dominant congenere in all samples (forest and agriculture), however, in considerably different concentrations. As expected, highest level was detected in forest organic layers, followed by forest top soils, cropland- and grassland top soils. Although highest in concentration, OCDD only contributes to 0.17% (both forest organic- and top soil layer), respectively, 0.4% (cropland) and 0.3% (grassland) to TEq. The influence of lower chlorinated homologues on TEq is strongest in forest top soils (72%) followed by 67% (forest organic layers), cropland top soil (63%) and grassland (61%). Although all homologue patterns (forest and agriculture) give a fairly similar picture, a test of significance (χ ²) proved a different population of forest samples.

Conclusions

The resemblance of the homologue patterns throughout all utilization suggests that agent levels are explained mainly by diffuse atmospheric depositions rather than by specific land use input.

     

Trendanalysen mit Mann-Kendall-Test und Theil-Schätzer

Goal and Scope

An extension for trend analysis with Mann Kendall test and Theil estimator is presented which enables the weighting of data by weight factors.

Methods

It is shown in which way the weighting can effect the outcome of a trend analysis. Weighting is done in relation to the different sample sizes of the data points. A value or an observation derived from many specimens will be considered more reliable than a value derived from only a few specimens and will thus get a higher weighting factor.

Results

When weighting is applied, this will effect the Theil estimator rather than the Mann Kendall test. As a result the regression line is tilted towards those points with higher weights.

Outlook

Future must show whether the extensions presented here and in part 1 prove to be practical for the trend analysis in environmental monitoring or not.     

Bestimmung des Ferntransports von persistenten organischen Spurenstoffen und der Umweltexposition mittels Modelluntersuchungen

Background, Aim and Scope

Many environmental pollutants are slowly degrading (persistent) and very mobile. They are semivolatile, i.e. they are partitioned between the environmental media of soil, water and air, and undergo long-range transport. The combined action of climate and substance properties determines the distributions and fate of these substances, among them as the persistent organic pollutants (POPs), other pesticides and industrial chemicals.

Main Features

Multicompartment chemistry-transport models are under development in order to study environmental exposure models.

Results

The investigation of transport and fate of some POPs on the global scale has emphasized the significance of historically explicit and geo-referenced simulations for substance distributions, persistence and long-range transport potential. Apart from the substance properties, it is the regional climate which is most important. This was illustrated by studies into the regional cycling of DDT and γ-HCH in selected tropical and extra-tropical regions.

Discussion

The isolation of individual steps of subsequent cycles of emission, transport and deposition (a so-called grasshopper effect) in model experiments shows the potential to elucidate the complex superposition of substance properties and environmental conditions, variable in time and space.

Conclusions

The results suggest that the grasshopper effect enhances the long-range transport potential, but is not required to explain an accumulation in polar regions (at least for γ-HCH).

Perspectives

A number of relevant scientific questions should be addressed by exposure modelling.     

Versuchsanlage zur energetischen Beurteilung von Substraten und Kofermentaten für Biogasanlagen

Goal, Scope and Background

Worldwide energy requirements are constantly increasing. Rising prices and the necessity to secure the future energy supply have led the decision-makers in politics and economy to focus on the more intensive use of their own resources. Before the background of possible climatic effects caused by the use of fossil energies, the use of renewable resources as primary energies, with its narrow C-circulation, have gained in importance, particularly in terms of economic aspects. The production of biogas is of specific interest here. It is a sensible ecological investment and a solid source of income for our agriculture.

Material and Methods

The operator uses a complex biological system in a plant with high investment costs. An economic operation is only possible if the process parameters are optimized and the properties of the substrates and the co-ferments are known. For the important determination of the blogas potential, we present an efficient and robust system, which is easy to handle and low cost, that has been developed by the LHL and LLH at the Eichhof. This procedure enables one to make statements on the implementation dynamics and is also suited to judge the fermentation process depending on the size of particles, as the co-ferments are used in a practice-oriented consistency.

Results

With the described fermentation apparatus you can not only assess the potential development of biogas and methane, but also the process of fermentation. The sum-graphs determined allow one to make conclusions on the implementation dynamics and, thus, on the optimization of the process. The advanced equipment makes it possible to determine the process of fermentation and the gas yield under different retention times and digester loads. The determination of the potential of the biogas and also the evaluation of the continuous fermentation are related to a specific correction factor won from the standard.

Discussion

A prerequisite for economic process management is the knowledge of the attainable gas yield and the fermentation process of substrates and co-ferments. A precise calibration is the quality basis for the results achieved with this method, as is the case with other fermentation tests as well. For the tests, a highly homogeneous substrate, which guarantees a continuous biological activity in the digesters, ought to be used. The possibility of determining optimum retention times and digester loads with this equipment makes costly tests with a full scale reactor unnecessary.

Conclusions

All tests run demonstrated that the fermentation apparatus originally developed to determine the biogas yield is absolutely suited to also assess the impact of different digester loads and retention times.

Recommendations

The problem of the suitability and the potential of different materials, the optimum reactor performance and the combination of different processes of energy generation from renewable but also conventional resources will increaseingly become the focus of laboratory tests. The following subjects have to be taken into account:

- Testing different materials on their suitability

- Evaluation security of common and new co-ferments

- Guidelines for mixtures to optimize reactor performance

- Mixtures of different substrates and co-ferments available to a particular operator (also with the help of simulation models)

- Processing changing quantity proportions of plants won from a rotation of crops altered for energy generation

- Other parameters like pre-fermentation, particle size and fer mentation supplements.

Perspective

These tests with a high practical relevance are supposed to contribute to a reliable method of producing biogas, in order to optimize the yield of gas production, but also to find a calibration of less costly procedures like those involving Near Infrared Spectroscopy (NIRS).     

Moosmonitoring als Spiegel der Landnutzung?

Goal, Scope and Background

The study was conducted to test the hypothesis that the regional variability of nitrogen (N) and metal accumulations in terrestrial ecosystems are due to historical and recent ways of land use. To this end, in two regions of Central Europe the metal and N accumulations in both regions should be examined by comparative moss analysis. The regions should be of quantitatively specified representativity for selected ecological characteristics of Europe. Within both regions these characteristics should be covered by the sites where the moss samples were collected. The number of samples should allow for geostatistical estimation of the measured nitrogen and metal loads.

Methods

The two regions of investigation were selected according to an ecological land classification of Europe which was computed by classification trees. Within each of both research areas the sampling points were localized according to the areas occupied by the ecologically defined land classes. The sampling and chemical analysis of mosses was conducted in accordance with an appropriate UNECE guideline by means of ICP-MS (metals) and combustion analysis (N). The quality of measurements was assured using certified reference materials. The differences of deposition loads were tested for statistical significance with regard to time and space. Variogram analysis was used to examine and model the spatial autocorrelation function of the measurements. Ordinary kriging was then applied for surface estimations.

Results

By use of the ecological regionalisation of Europe the Weser-Ems Region (WER) and the Euro Region Nissa (ERN) were selected for investigation. The sampling sites represent quite well the natural landscapes and the land use categories of both regions. The measurement values corroborate the decline of metal accumulation observed since the beginning of the European Mosses Monitoring Survey in 1990. The metal loads of the mosses in the ERN exceed those in the WER significantly. The opposite holds true for the N concentrations: those in the WER are significantly higher than those in the ERN.

Discussion

The decrease of heavy metal emissions is correlated with lowered deposition and accumulation rates in terrestrial ecosystems. The accumulation of nitrogen in the biosphere is not following this trend.

Conclusions

The technique of moss analysis is adequate for spatially valid biomonitoring of spatial and temporal trends of metals and nitrogen in terrestrial ecosystems. By this, it enables to prove the efficiency of environmental policies.

Recommendations and Perspectives

The accumulation of N in ecosystems is still a serious environmental problem. Related ecological impacts are the eutrophication of aquatic ecosystems like ground waters, lakes, rivers and oceans as well as the biocoenotic changes in terrestrial ecosystems. Thus, a statistically valid exposure analysis must encompass both, accumulation of metals and N bioaccumulation. Further, the bioaccumulation of persistent organic pollutants should be monitored. Finally, environmental biomonitoring should be conducted in much closer contact with human health aspects.