Which impact does the use of non-energetic abiotic resources (ores, minerals, etc.) have in life cycles of energy systems based on biogenic and fossil fuels? Is this kind of resource use less or more environmentally harmful than the utilisation of energetic abiotic resources (mineral oil, natural gas, etc.) in the same life cycles? This paper aims at answering these questions. In Part 1, a methodology is presented and applied to the life cycles of selected energy systems. Part 2 presents and discusses the results.
Method
This study looks at the complete life cycles of selected energy systems. The methodology used bases on the state-of-the-art of life cycle assessment (LCA) methodology. For the assessment of energetic abiotic resource use, a widely recognised method can be used. For the assessment of non-energetic abiotic resource use, no overall recognised methodological approach exists. That is why for this aspect two different methods are exemplarily applied and compared with each other.
Results and Conclusion
Results will be presented and discussed in Part 2.
Recommendation and Perspective
Recommendation and conclusions will be derived from study results in Part 2. 相似文献
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. 相似文献
The purpose of the study is the enhancement of criticality assessments for resources in order to address function specific factors like dissipation, recycling, bio-activity and toxicity. The developed methodology is applied to platinum-containing cytostatic drugs and automotive catalytic converters.
Methods
The study is methodically based on an analysis of resource specific factors like exploration rates, reserves-to-production ratio and regional distribution of exploration areas as well as on the investigation of product/functional depending factors like recycling rates, dissipation rates, bio-diversity and toxicity. Taking into account that economic and ecological risks may occur at any stage of the supply, consumption and dissipation processes, the whole life cycles of the two analyzed products (cytostatic drugs and automotive catalytic converters) are considered. As an approach to reduce potential economic and ecological risks the study is especially focused on recycling strategies.
Background
In order to get a better understanding of platinum as an essential resource for the development of our society the history and the cultural impact of the term "resource" are introduced.
Results & Discussion
The availability of platinum is crucial for several products of our modern society. Areas of application are e.g. jewellery, automotive catalytic converters, investments (coins, bars), computers, mobile devices, fertilizers and cytostatic drugs. Economic risks are caused by limited sources and dynamic demand of new application areas like fuel cells and drugs. Platinum-containing drugs are used for the treatment of several kinds of cancer such as testicular, breast, colon and prostate. Currently the pharmaceutical industry requires 6,9 tons per year (3 percent of the total demand of platinum). Due to the improvement of medical standards and the ageing society, especially in developing countries, the demand of platinum-containing drugs will rise significantly. The dissipation of toxic soluble salts and the lack of advanced waste-water treatment and recycling systems is a problem of the usage of platinum-containing drugs. Compared with cytostatic drugs (14.6 kg/a for Germany) the dissipation of platinum particles of mobile catalytic converters is much higher (5-20 tons/a only in North America, Europe and Japan; 184,2 kg/a in Germany). On the other hand the emission of platinum nano-particles of automotive catalytic converters seems less critical. Furthermore advanced recycling technologies are already available for them.
Conclusions
The evaluation of resources has to consider resource specific and functional depending factors. In order to reduce economic and ecological risks of the dissipation of platinum salts in cytostatic drugs three principle options can be identified: the development of ecologically compatible and cost-effective substitutes, efficient recycling systems and future-oriented sanitary-systems as well as waste-water treatment facilities, which are able to separate platinum salts. Concerning the dissipation of platinum particles of mobile converters relevant research questions are the identification of adequate substitutes as well as the extension of recycling capacities.
Recommendations and perspectives
The study demonstrates a research gap concerning substitutes for automotive catalytic converters as well as for platinum-containing cytostatic drugs. The development and implementation of recycling concepts, technologies and capacities to reuse platinum as a secondary resource is an essential issue. As a consequence the economic and ecological risks can be reduced by increasing the resource efficiency. Special research has to be done concerning the development of future-oriented sanitary-systems and waste-water treatment facilities in order to separate platinum in waste water. Furthermore, if the future demand of new products like fuel cells is considered, a resource conflict concerning the potential functional applications will be evident. In order to address these challenges the criticality assessment has to be enhanced by ethic and social factors. 相似文献
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). 相似文献
Through their use of energy and materials, universities cause a great deal of environmental pollution which could be reduced considerably by an effective choice of organizational and technical measures. There are some examples for environmental protection measures at several universities, but a professional environmental management system (EMS) for universities with a systematic approach to reduce the consumption of resources is lacking. At the University of Osnabrück, the basis for an EMS applicable for a university has been developed for the first time in Germany and the use of this system can also be transferred to other universities. The EMS is composed of ten building blocks, for example, alteration of the administration’s organizational structure, adoption of environmental guidelines, analysis of the energy and material flows which result in an eco-balance, an environmental program or measures to inform the staff and to help to involve them in environmental management. Over the next months, these ten building blocks will gradually be implemented at the University of Osnabrück. Five articles will provide an overview about the EMS developed for the University of Osnabrück as a whole and will describe parts of the material and energy flow analysis, and the planned environmental information system.
Part I: An Environmental Management Model for Universities: From Environmental Guidelines to the Involvement of Employees
Part II: The Energy Balance of the University of Osnabrück: Analysis of the Energy Flows and Conclusions
Part III: The Traffic Balance of the University of Osnabrück: Calculation of the Environmental Pollution which is caused by the University’s Commuters and Business Trips
Part IV: A Concept of Waste Reduction for the University of Osnabrück: Constructing the Waste Balance and Measures to Inform and Involve the Staff
Part V: The Planned Environmental Information System of the University of Osnabrück: Concept and Integration into the Management Information System
Environmental assessment of aquatic micro pollutants should consider the spatial and temporal variability of emission, transport and transformation. Simulation models coupled with Geographic Information Systems (GIS) provide digital maps of concentration patterns caused by the overlay of multipoint and diffuse emissions and natural attenuation processes in river basins. The paper gives an overview on GIS-based models for river basins and demonstrates the applicability by using some illustrating examples with GREAT-ER.
Main Features
Georeferenced models have several advantages: visualization of concentration patterns, investigation of spatial and temporal concentration profiles, analysis of exceedance of environmental quality standards, embedding in integrated river basin management systems.
Results and Discussion
GIS-based models allow a more realistic assessment. Monitoring programmes should be designed to deliver appropriate measured data for the evaluation and improvement of models.
Recommendation and Perspectives
The combination of digital maps, simulation models and environmental monitoring would provide better approaches for the risk assessment and water quality management of aquatic micro pollutants. 相似文献
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. 相似文献
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. 相似文献
Sorting and disposal of waste are the last steps in the “lifetime” of a product. If products are contaminated with chemicals assessed to be hazardous for man or environment, waste management has the role of a vacuum cleaner in substance chain management working in two different ways: The hazardous compounds have to be properly separated from potential secondary resources in sorting processes. If this is not possible, those products have to be disposed safely. Starting from the experiences collected with some chemicals banned, the tools used for phasing out these chemicals from the technosphere are studied with respect to their influence on the contamination of the environment.
Results
Even if a dangerous substance has been banned, it is further used in a number of products. In the cases presented here, the substances were banned for further use. In the case of CFCs, the substitutes used have partially also been substituted because of adverse effects. Besides the prohibition of use of hazardous substances, numerous other regulations were issued to reduce unsafe handling and minimize emissions into the environment. It turned out that waste management cannot correct mistakes which already happened “upstream” in the product chain. The control of point sources works quite successfully, whereas today the overwhelming emissions stem from diffuse sources, partially caused by unsafe waste management procedures.
Conclusions
Though there are no complete balances for both groups of compounds serving as examples, some conclusions can be drawn based on the experiences collected. Hazardous compounds may be separated successfully from used products or waste,
If they are mostly used in industry and not in households,
if they can be identified as part of certain products,
if their concentration in these products is rather high,
if technical problems come up when they contaminate secondary raw materials,
if there is international support for proper waste management.
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. 相似文献
The Cefic Mixtures Industry Ad-hoc Team (MIAT) has investigated how risks from combined exposures can be effectively identified and managed using concepts proposed in recent regulatory guidance, new advances in risk assessment, and lessons learned from a Cefic-sponsored case study of mixture exposures.
Results
A series of tools were created that include: a decision tree, a system for grouping exposures, and a graphical tool (the MCR-HI plot). The decision tree allows the division of combined exposures into different groups, exposures where one or more individual components are a concern, exposures that are of low concern, and exposures that are a concern for combined effects but not for the effects of individual chemicals. These tools efficiently use available data, identify critical data gaps for combined assessments, and prioritize which chemicals require detailed toxicity information. The tools can be used to address multiple human health endpoints and ecological effects.
Conclusion
The tools provide a useful approach for assessing risks associated with combined exposures to multiple chemicals. 相似文献
Production and use of substances and formulations can result in exposures on humans and the environment. In October 2003, the European Commissions presented a proposal for the registration, evaluation, assessment and restriction of chemicals (REACH). Assessment of exposures will become an essential element of REACH for certain substances. For many manufacturers and users of substances and formulations these tasks are new. Pilot projects to REACH have shown so far that solutions and instruments for these tasks which meet the requirements of real life situations have yet to be developed.
Discussion and Conclusions
Within the REACH proposal, exposure scenarios are a main element of the chemical safety assessment. This article outlines the contents of exposure scenarios. It reflects experiences with exposure scenarios and discusses possibilities of standardization. It covers exposure steps/categories and possibilities to build product groups. Non-branch specific types of exposure situations are an important element of exposure scenarios. Therefore, exposure steps/categories should be contained in exposure scenarios. Nevertheless, these elements structure only a specific part of the information contained in exposure scenarios. Hence they cannot replace exposure scenarios. Exposure categories do not reveal the uses, the processes and the activities connected with the intended use of substances. These information are important parts of a complete exposure scenario. They are the basis for the following step of risk characterisation. In addition, they provide the necessary transparency regarding the use patteern of substances. 相似文献
The marine shipping lanes have become the most important path for the invasion of foreign aquatic organisms. The increasing global trade results in an increase in the number of marine vessels. Without any protective measures, with every ship carrying foreign organisms the risk of biological invasions will rise.
Results
The International Martime Organization (IMO) of the United Nations developed a convention to reduce the transfer of organisms with ballast water. After the entry-into-force of this convention the fleet of the world has to be equipped with effective ballast water management technology before 2016. This article discusses potential options for action. To comply with the limit values of the ballast water convention, the current state of the art demands the use of active substances. Any decision on the approval of active substances used for ballast water treatment and the environmental impact assessment lies with the IMO. Proposed to day are UV-radiation, active chlorine, active oxygen, the creation of biocides through electrolysis and a change in gases contained in the ballast water. The technologies and the potential risks are presented.
Conclusions
Despite the introduction of an approval procedure by IMO any reliable assessment of the real risks involved in the use of biocides is impossible, as the risk assessment approaches have still to be developed. On the regulatory level, the main focus in data requirements for the risk assessment is on a comprehensive testing of the toxic potential of the biocides proposed. Strategies for the identification and evaluation of the chemical resulting from the treatment of limnic, marine and brackish water are not fully developed. An integrating assessment of risks involved in the introduction of foreign organisms versus the toxic effects of the substances used or created during treatment is still missing. 相似文献
A vast amount of data on the concentration of substances in soils is being generated in environmental monitoring programmes. This data has to be assessed in terms of effects on terrestrial biota. Benchmarks for such an assessment have been missing up to now. This gap has been filled by the development of a concept for the derivation of ecotoxicologically based soil quality criteria (SQC) and the application of this concept to environmentally relevant substances.
Objectives
The derivation method was applied to arsenic. The derivation process was described in detail from the compilation of data regarding effects on microbial processes, plants, and soil invertebrates to the formulation of a recommendation for an SQC.
Methods
The conceptual framework for the derivation of ecotoxicologically based SQC was developed after reviewing national and international concepts for the assessment of the effects of substances on terrestrial communities. For the assessment of arsenic effects, all relevant biotic processes and trophic levels have been taken into account. Moreover, soil characteristics that may affect the toxicity to biota have been reviewed.
Results
Effects of arsenic on biota may occur at soil background concentrations or slightly above. There are only a few studies in which the influence of soil characteristics, such as soil pH, soil texture, and soil organic carbon, on the effects of arsenic has been investigated systematically. That is why the SQC was oriented on soil background concentrations for sandy soils (5 mg As/kg soil dw). A comparison of the SQC derived in this work with ecotoxicologically based soilquality values from Canada, Denmark, the Netherlands, and the United States shows an average value of 16 mg As/kg, with a range between 5 and 34 mg/kg. The variations in the soil quality values are mainly due to differences in the derivation approaches.
Conclusions and Outlook
The concept applied is considered suitable for the derivation of SQC designed to protect terrestrial communities against direct effects of substances in soils. Therefore, its use is planned to derive SQC for other environmentally relevant substances. In addition to compensation factors, statistical methods should be taken into account to compensate for risks which cannot be quantified. Furthermore, there is the need for an assessment of indirect effects of soil contaminants on birds and mammals. 相似文献
Soil organisms play a crucial role in the terrestrial ecosystem. Plant Protection Products (PPPs) are known to affect soil organisms and might have negative impacts on soil functions influenced by these organisms. Little research has been done to day on the impact of PPs on tropical ecosystems. Therefore, in this study it was investigated whether fate and effects of pesticides differ between tropical and temperate regions and whether data generated under temperate conditions can be used for the Environmental Risk Assessment (ERA) in tropical regions.
Methods
In the first part of this study, the effects of two fungicides (Benomyl and Carbendazim) and one insecticide (lambda-Cyhalothrin) on soil invertebrates (i.e. earthworms and arthropods) were evaluated in laboratory tests modified for tropical conditions (temperature, soil, test species). Besides using some native species, the tests were done mainly with two (temperate and tropical) strains of earthworms (Eisenia fetida) and the peregrine isopod speciesPorcellionides pruinosus as standard test species. The chemicals were spiked in two natural and two artificial soils. A tropical artificial soil (TAS), containing a tropical fern product (Xaxim) or coconut coir dust as organic matter, was developed in this study.
Results and Conclusions
The results from the laboratory tests showed that all three test chemicals differed from those gained under temperate conditions. In the case of the fungicides the toxicity was lower but in the case of the insecticide higher under tropical than under temperate conditions. The native tropical earthwormPontoscolex corethrurus reacted more sensitively against Carbendazim in comparison to the standard test speciesEisenia fetida.
Recommendation and Perspective
Details of the environmental risk assessment of the three model chemicals based on the results of the laboratory described here (and including the results of higher tier tests (semi-field and field tests)) will be described in Part 2 of this series 相似文献
Bioelectrochemical systems (BES) have been extensively studied for resource recovery from wastewater. By taking advantage of interactions between microorganisms and electrodes, BES can accomplish wastewater treatment while simultaneously recovering various resources including nutrients, energy and water (“NEW”). Despite much progress in laboratory studies, BES have not been advanced to practical applications. This paper aims to provide some subjective opinions and a concise discussion of several key challenges in BES-based resource recovery and help identify the potential application niches that may guide further technological development. In addition to further increasing recovery efficiency, it is also important to have more focus on the applications of the recovered resources such as how to use the harvested electricity and gaseous energy and how to separate the recovered nutrients in an energy-efficient way. A change in mindset for energy performance of BES is necessary to understand overall energy production and consumption. Scaling up BES can go through laboratory scale, transitional scale, and then pilot scale. Using functions as driving forces for BES research and development will better guide the investment of efforts.
While the rise of the air temperature as part of the global climatic change seems to be widely assured, questions about the effects of this phenomenon in ecological systems get more and more interesting. In this sense this article shows by the example of monitoring sites in Baden-Württemberg the correlation of air temperature measurements with data on the phenology of selected plants.
Methods
To this end the data on air remperature and plant phenology which are gathered from spatial dislocated measurement sites were correlated by prior application of Kriging interpolation. In addition, geostatistics are ssed to analyze and cartographically depict the spatial structure of the phenology in spring and in summer.
Results and Conclusion
The statistical analysis reveals a significant relationship between the rising air temperature and the early beginning phenological phases like blooming or fruit maturation. From 1991 to 1999 spring time as indicated by phenological phases begins up to 14 days earlier than from 1961 to 1990. As proved by geostatistics, this holds true for the whole territory of Baden-Württemberg.
Recommendation and Perspective
The effects of the rise of air temperature should be examined not only by monitoring of biological individuals as for example plants, but on ecosystem level, too. The German ecosystem research and the environmental monitoring should be supplemented by the study of the effects of the climatic change in ecosystems. Because air temperature and humidity have a great influence on the temporal and spatial distribution of pathogen carriers (vectors) and pathogens mapping of the determinants of vector and pathogen distribution in space and time should be done in order to identify hot spots for risk assessment and further detailed epidemiological studies. 相似文献
The state of the art on sources, transport and environmental fate, human exposure and toxicological risk assessment of dioxin-like polychlorinated biphenyls (PCB), and non dioxin-like PCB is described and summarized with focus on Germany and neighbouring countries.
Methods
Presentations and discussions of a two-days symposium in Germany are the primary source of information. The significance of dioxin-like PCB is evaluated in relation to polychlorinated dibenzo-p-dioxins (PCDD) and dibenzofurans (PCDF). For that purpose, toxicity equivalent concentrations (TEQ) of both groups of contaminants in environmental matrices are compared.
Results and Conclusions
TEQ values of dioxin-like PCB are comparable to those of PCDD/PCDF in many environmental media; in food of animal origin PCB-TEQ is even higher. In most media, the non-ortho substituted PCB 126 has by far the highest contribution to the PCB-TEQ due to its high toxicity equivalency factor of 0.1. Atmospheric (long-range) transport obviously plays the major role for the diffuse PCB contamination of the environment. The transfer atmosphere-plant is apparently the key process for the entrance of dioxin-like PCB into terrestrial food chains.
Recommendation and Perspective
In spite of the decline of environmental contamination with PCB and PCDD/PCDF, a significant part of the general population in Germany and other European countries currently exceeds the tolerable intake of dioxin-like substances. However, also the results of a new toxicological risk assessment of non dioxin-like PCB implicate the need of further reduction of PCB exposure. 相似文献
The development of criteria for the comparative assessment of technologies and substances beyond the toxicological approach and the development of an integrated pattern of criteria is still at the beginning. The criteria presented here for integrating the precautionary principle into the substance and technology assessment have to be further operationlised and completed, in the same way as the criteria which have been discussed and developed within the framework of
- the poisoning and pollutant paradigm
- the equilibrium paradigm
- the sustainability and “Mitwelt” paradigm
- the energy and the general technology assessment debate.
The resolution of the criteria has to be improved and their range (which is certainly limited) has to be explored more precisely. The application of the criteria should never occur mechanically. Technology assessment and substance assessment are not only scientific, but essentially social and, hence, discursive processes. It is not so much the assessment of individual substances which should be in the center of the debate, but rather the comparative assessment of competing techniques, substances and substancerelated development pathways (see vonGleich andRubik, 1966 as a first approach to assess the environmental effects of old and new materials). According to the example of the energy strategies, only the development of competing strategies in the substance field could create the necessary prerequisites for a broad public discourse and thus for a democratisation of the basic substancerelated policy decisions. This discourse is a duty which science and economy have toward society. 相似文献
