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Результаты 671-680 из 775
The Cl-initiated oxidation of CH₃C(O)OCH=CH₂, CH₃C(O)OCH₂CH=CH₂, and CH₂=CHC(O)O(CH₂)₃CH₃ in the troposphere
2009
Blanco, María B. | Bejan, Iustinian | Barnes, Ian | Wiesen, Peter | Teruel, Mariano A.
Background, aim, and scope Unsaturated esters are emitted to the atmosphere from biogenic and anthropogenic sources, including those from the polymer industry. Little information exists concerning the atmospheric degradation of unsaturated esters, which are mainly initiated by OH radicals. Limited information is available on the degradation of alkenes by Cl atoms and almost no data exists for the reactions of unsaturated esters with Cl atoms. This data is necessary to assess the impact of such reactions in maritime environments where, under circumstances, OH radical- and Cl atom-initiated oxidation of the compounds can be important. Rate coefficients for the reactions of chlorine atoms with vinyl acetate, allyl acetate, and n-butyl acrylate have been determined at 298 ± 3 K and atmospheric pressure. The kinetic data have been used in combination with that for structurally similar compounds to infer the kinetic contributions from the possible reaction channels to the overall reaction rate. Materials and methods The decay of the organics was followed using in situ Fourier transform infrared spectroscopy and the rate coefficients were determined using a relative kinetic method and different hydrocarbon reference compounds. Results The following room temperature rate coefficients (in cm³ molecule⁻¹ s⁻¹) were obtained: k ₁ (Cl + CH₃C(O)OCH=CH₂) = (2.68 ± 0.91) x 10⁻¹⁰, k ₂ (Cl + CH₃C(O)OCH₂CH=CH₂) = (1.30 ± 0.45) x 10⁻¹⁰, and k ₃ (Cl + CH₂=CHC(O)O(CH₂)₃CH₃) = (2.50 ± 0.78) x 10⁻¹⁰, where the uncertainties are a combination of the 2σ statistical errors from linear regression analyses and a contribution to cover uncertainties in the rate coefficients of the reference hydrocarbons. Discussion This is the first kinetic study of the title reactions under atmospheric conditions. The kinetic data were analyzed in terms of reactivity trends and used to estimate the atmospheric lifetimes of the esters and assess their potential importance in the marine atmosphere. Conclusions Although reaction with OH radicals is the major atmospheric sink for the unsaturated esters studied, reaction with Cl atoms can compete in the early morning hours in coastal areas where the Cl concentration can reach peak values as high as 1 x 10⁵ atoms cm⁻³. The calculated residence times show that the chemistry of unsaturated esters will impact air quality locally near their emission sources. Recommendations and perspectives The reactions need to be studied over the range of temperatures and pressures generally encountered in the marine atmosphere. In addition, product studies should also be performed as a function of temperature since this will allow degradation mechanisms to be derived, which are representative for the wide range of conditions occurring in marine environments. Inclusion of the kinetic and product data in tropospheric numerical models will allow an assessment of potential environmental impacts of the esters for different marine pollution scenarios.
Показать больше [+] Меньше [-]A multibiomarker approach using the polychaete Arenicola marina to assess oil-contaminated sediments
2009
Morales-Caselles, Carmen | Lewis, Ceri | Riba, Inmaculada | DelValls, T Ángel | Galloway, Tamara
Background, aim and scope Marine and coastal sediments can accumulate substantial concentrations of metals and hydrocarbons, yet the consequences of this contamination for exposed biota in situ can be difficult to establish. Here, we examine the hypothesis that exposure to contaminated sediments can lead to detrimental effects in sediment-dwelling species. The combination of chemical and biological assessment allows the identification of the impact of chemical contamination, and their use as assessment tools is becoming increasingly important. Materials and methods The study was applied to marine sediments from the Bay of Algeciras (S Spain) impacted by multiple, low-level contaminant inputs, and the Galician Coast (NW Spain), historically impacted by an oil spill (Prestige 2002), with two reference sites selected in UK and Spain. The common lugworm Arenicola marina was exposed in the laboratory for 14 days to the marine sediments, and a suite of biomarkers of sublethal toxicity was combined with analytical chemistry to test for relationships between sediment contamination and effect. Results Moderate to strong correlations between organics, metals, and biological responses were observed, with DNA damage as measured using the Comet assay forming the largest contribution toward the observed differences (p < 0.05). The responses of worms from sites experiencing different contamination loads were clearly distinguishable. Discussion We show how a combination of multibiomarkers with analytical chemistry can be used to investigate the toxicity of marine sediments, enabling the differentiation of sites showing different types of contamination. There are clear relationships in sublethal assays that can be related to the putative mode of toxicity of the contaminants. Conclusions The use of A. marina in this way provides a sensitive, holistic approach to sediment toxicity assessment, enabling comparisons between oil-polluted sites to be quantified. Recommendations and perspectives These tools provide a relatively simple, rapid, and economic way to test the environmental status of oil-contaminated sediment.
Показать больше [+] Меньше [-]Reduction of nitrogen loss and Cu and Zn mobility during sludge composting with bamboo charcoal amendment
2009
Hua, Li | Wu, Weixiang | Liu, Yuxue | McBride, Murray B. | Chen, Yingxu
Background, aim, and scope Composting is an effective treatment process to realize sludge land application. However, nitrogen loss could result in the reduction of nutrient value of the compost products and the stabilization effect of composting on heavy metal concentration and mobility in sludge has been shown to be very limited. Materials and methods Laboratory-scale experiments were carried out to investigate the effects of bamboo charcoal (BC) on nitrogen conservation and mobility of Cu and Zn during sludge composting. Results The result indicated that the incorporation of BC into the sludge composting material could significantly reduce nitrogen loss. With 9% BC amendment, total nitrogen loss at the end of composting decreased 64.1% compared with no BC amendment (control treatment). Mobility of Cu and Zn in the sludge may also have been lessened, based on the decline in diethylenetriaminepentaacetic acid-extractable Cu and Zn contents of composted sludge by 44.4% and 19.3%, respectively, compared to metal extractability in the original material. Discussion Ammonia adsorption capability of BC might be the main reason for the retention of nitrogen in sludge composting materials. Decrease of extractable Cu²⁺ and Zn²⁺ in the composting material mainly resulted from the adsorption of both metals by BC. Conclusions Incorporation of BC into composting material could significantly lessen the total nitrogen loss during sludge composting. Mobility of heavy metals in the sludge composting material could also be reduced by the addition of BC. Recommendations and perspectives Bamboo charcoal could be an effective amendment for nitrogen conservation and heavy metal stabilization in sludge composts. Further research into the effect of BC-amended sludge compost material on soil properties, bioavailability of heavy metals, and nutrient turnover in soil needs to be carried out prior to the application of BC-sludge compost in agriculture.
Показать больше [+] Меньше [-]Contents and sources of DDT impurities in dicofol formulations in Turkey
2009
Turgut, Cafer | Gokbulut, Cengiz | Cutright, Teresa J
Background, aim, and scope Dicofol is widely used as a pesticide in agriculture applications. Since dicofol is mainly synthesized from dichlorodiphenyltrichlorethane (DDT), it contains DDT as an impurity. The European Community has forced Prohibition Directive 79/117/EEC to reduce DDT in dicofol formulations. Specifically, DDT content in a dicofol formulation cannot exceed 0.1%. The goal of this project was to determine the DDT content in dicofol formulations used in Turkey. Materials and methods Samples of all the dicofol formulations in Turkey were collected to quantify DDT and DDT-related compounds. Four replicates were used for each sample. GC/MS/MS was used to analyze p,p' and o,p' isomers of DDT, DDD, and DDE. A HPLC was used to determine p,p'-Cl-DDT concentrations. Results The total DDT content of the formulated dicofol was found between 0.3% and 14.3%. The concentration of p,p'-DDE ranged from 167 to 1,042 mg kg⁻¹ in dicofol samples. p,p'-DDT concentrations were found to be 32 to 183 mg kg⁻¹. The o,p'-DDT level ranged from 2 to 34 mg kg⁻¹ in the dicofol formulations analyzed. Discussion It was estimated that 617.8 kg of DDT was released from dicofol. The main impurity was identified as p,p-Cl-DDT. Based on these results, dicofol serves as a continuing source of DDT contamination. Conclusions All DDT concentrations in dicofol samples analyzed were higher than the permitted 0.1% level of Prohibition Directive 79/117/EEC. The reduction of dicofol is critical since it serves as a continual source of DDT contamination. Recommendations and perspectives DDT has been found in soil, water, and air samples. Dicofol has been identified as a contributor to continued DDT contamination in soil and water. More studies are needed to ascertain the source of DDT in the air.
Показать больше [+] Меньше [-]Risk assessment of boron in glass wool insulation
2009
Jensen, Allan Astrup
Background, aim and scope Glass wools are man-made vitreous fibres, which consist principally of sodium, calcium and magnesium silicates, but may contain smaller amounts of other elements, including boron. The boron contents originate from the use of borates in the glass melting process as a glass former and a flux agent. During the production and application of glass wool insulation products, workers may legally be exposed to glass fibre up to the occupational limit value, commonly of 1 fibre/cm³. However, in practice, the fibre exposure will be at least ten times lower. Boron is a non-metallic element widely distributed in nature, where it occurs as boric acid, borates and borosilicates. Humans are mainly exposed to boron via vegetarian food and drinking water, mineral supplements and various consumer products. Boron is an essential element for plant growth, but the essentiality for humans is not proven, although intakes of trace amounts of the element seem to be useful for bone health and proper brain function; higher concentrations of boron, however, may be toxic. In relation to the European Union legislation on dangerous substances, an EU Expert Group has recommended classifying boric acid and borates with risk phrases for reproductive toxicity. The aim of this paper is to assess whether the new EU hazard classification of boron compounds should imply that glass wool products used for building insulation in the future should be labelled, “may impair fertility and cause harm to the unborn child”, because of the low boron content. Materials and methods Boron intakes are estimated in a worst-case occupational situation with human exposure to glass wool fibres at the occupational limit of 1 fibre/cm³ by calculation of the mass of the amount of fibres inhaled during an 8-h work day. Fibres are supposed to be cylinders of glass with a length of 30 μm, an average diameter of 1.5-2 μm and containing either 1.5% or 3.5% boron. As a worst-case scenario, the density of the fibres is set to 2,700 kg/m³. The inhalation rate of the individuals at moderate work load was set to 2 m³/h. A worst-case scenario also corresponds to 100% retention and to 100% solubility of the retained fibres in the lungs. Results With the normal boron content of 1.5% in glass wool fibres for building insulation, the extra daily occupational boron intake/uptake will be 0.03-0.06 mg B for 5 days a week. For more uncommon glass wool with maximum boron content of 3.5%, the worst-case daily boron intake/uptake will be 0.08-0.16 mg B. The main boron exposure in the general population is from vegetarian food, and the average daily dietary intake with food is estimated to 1.2-1.5 mg B/day. In addition, significant intakes may come with drinking water, especially from mineral water. In some instances, exposure from mineral supplements, cosmetics and other consumer products may be significant. For example, individuals taking mineral supplements, e.g. for bodybuilding, may have an additional intake to that of 1-10 mg/day. During the years, various organisations have recommended safe intake values for boron. Recently, the Scientific Panel on Dietetic Products, Nutrition and Allergies of the European Food Safety Authority (EFSA) has established the 'Tolerable Upper Intake Level' (UL) for the intake of boron (boric acid and borates) at 0.16 mg B/kg body weight per day or about 10 mg B/day for an adult. Discussion The calculated, worst-case exposure scenario during an 8-h work day will result in an extra daily boron intake that only corresponds to about 10% of the average daily adult boron intakes through food and drinks of about 1.5 mg. The inter-individual variations in boron intakes from foods, water and supplements will be much greater than an eventual, very worst-case, additional intake of boron from inhalation of glass wool fibres. In addition, the combined intakes are far lower than the 'Tolerable Upper Intake Level' of 10 mg B/day for a person weighing 60 kg, as recommended by the European Food Safety Agency. The potential boron intake from inhalation of glass wool fibres is also much lower than boron intakes by workers in the boron industry, who at the present occupational limit value will be exposed to 50 mg of boron 5 days a week, or 100 times more than the worst case for glass wool fibres. Furthermore, in practice, exposure levels will mostly be ten to 100 times lower than the occupational limit used here as a worst case. Conclusions The estimated boron intake from inhalation of glass wool fibres in occupational settings will be insignificant and without any health risks, even in the case of non-compliance with the occupational limit value. Any proposal requiring hazard labels on commercial glass wool products for building insulation, because of the boron content, is not supported by the present scientific knowledge. Recommendations and perspectives The European Commission should ensure that the new EU hazard classification of boron compounds is not applied to commercial glass wool products for building insulation having a low content of boron.
Показать больше [+] Меньше [-]Endosulfan in China 2--emissions and residues
2009
Jia, Hongliang | Sun, Yeqing | Li, Yi-Fan | Tian, Chongguo | Wang, Degao | Yang, Meng | Ding, Yongshen | Ma, Jianmin
Background, aim, and scope Endosulfan is one of the organochlorine pesticides (OCPs) and also a candidate to be included in a group of new persistent organic pollutants (UNEP 2007). The first national endosulfan usage inventories in China with 1/4° longitude by 1/6° latitude resolution has been reported in an accompanying paper. In the second part of the paper, we compiled the gridded historical emissions and soil residues of endosulfan in China from the usage inventories. Based on the residue/emission data, gridded concentrations of endosulfan in Chinese soil and air have been calculated. These inventories will provide valuable data for the further study of endosulfan. Methods Emission and residue of endosulfan were calculated from endosulfan usage by using a simplified gridded pesticide emission and residue model--SGPERM, which is an integrated modeling system combining mathematical model, database management system, and geographic information system. By using the emission and residue inventories, annual air and soil concentrations of endosulfan in each cell were determined. Results and discussion Historical gridded emission and residue inventories of α- and β-endosulfan in agricultural soil in China with 1/4° longitude by 1/6° latitude resolution have been created. Total emissions were around 10,800 t, with α-endosulfan at 7,400 t and β-endosulfan at 3,400 t from 1994 to 2004. The highest residues were 140 t for α-endosulfan and 390 t for β-endosulfan, and the lowest residues were 0.7 t for α-endosulfan and 170 t for β-endosulfan in 2004 in Chinese agricultural soil where endosulfan was applied. Based on the emission and residue inventories, concentrations of α- and β-endosulfan in Chinese air and agricultural surface soil were also calculated for each grid cell. We have estimated annual averaged air concentrations and the annual minimum and maximum soil concentrations across China. The real concentrations will be different from season to season. Although our model does not consider the transport of the insecticide in the atmosphere, which could be very important in some areas during some special time, the estimated concentrations of endosulfan in Chinese air and soil derived from the endosulfan emission and residue inventories are in general consistent with the published monitoring data. Conclusions To our knowledge, this work is the first inventory of this kind for endosulfan published on a national scale. Concentrations of the chemical in Chinese air and agricultural surface soil were calculated for each grid cell. Results show that the estimated concentrations of endosulfan in Chinese air and soil agree reasonably well with the monitoring data in general. Recommendations and perspectives The gridded endosulfan emission/residue inventories and also the air and soil concentration inventories created in this study will be updated upon availability of new information, including usage and monitoring data. The establishment of these inventories for the OCP is important for both scientific communities and policy makers.
Показать больше [+] Меньше [-]Eutrophication of Lake Tasaul, Romania--proposals for rehabilitation
2009
Alexandrov, Mihaela Laurenta | Bloesch, J (Jürg)
Lake Tasaul on the Black Sea coast is highly eutrophic, but not strongly contaminated (heavy metals, PAHs, and organochlorine pesticides). Cyanophytes dominate phytoplankton by 67-94% and form frequent algal blooms. High primary production (up to 270 mg Cass/m².h) and algal biomass (maximum chlorophyll a concentration 417 μg/l) may be controlled by light, as Secchi depth is often below 1 m. The main tributary, Casimcea River, provides high quantities of suspended matter and about 3 tons TP/year and 660 tons TN/year. Based on chemical and biological analysis as well as fishery investigations, we provide recommendations for Lake Tasaul rehabilitation.
Показать больше [+] Меньше [-]Adsorption of lambda-cyhalothrin and cypermethrin on two typical Chinese soils as affected by copper
2009
Liu, Jun | Lü, Xiaomeng | Xie, Jimin | Chu, Yafei | Sun, Cheng | Wang, Qian
Background, aim, and scope Pesticides and heavy metals pollution in soil environment has become a serious problem in many countries including China. Repeated applications of bordeaux mixture (a blend of copper sulfate and calcium hydroxide) and pyrethroid (Pys) insecticides have led to elevated copper (Cu) and Pys concentrations in vineyard surface soils. However, few studies focused on the interaction of Pys and heavy metals in the soil environment. Our previous studies had indicated the combined effect of cypermethrin (CPM) and Cu on soil catalase activity. Also, we had suggested that the addition of Cu could catalyze photo-degradation of CPM and lambda-cyhalothrin (λ-CHT) in aqueous solution and restrain their degradation in soil. To better understand the potential influence of Cu on the fate of Pys in the soil environment, the aim of the present work was to examine the effect of Cu on the adsorption of λ-CHT and CPM on two typical Chinese soils with different soil characteristics, which was one of the key processes controlling the fate of Pys, and to provide more information about the potential ecological risk of chemicals on the soil ecosystem. Fourier transform infrared and point charges analysis using the MOPAC program of the Gaussian system were also used to reveal the probable adsorption mechanism of λ-CHT and CPM on soils. Materials and methods Two vineyard soils with different properties were chosen as experimental samples. They were sampled from 0 to 10 cm, dried, and sieved to 2 mm. Each soil was spiked with copper sulfate solution to obtain the following total soil Cu concentrations: 100, 200, 400, 800, and 1,600 mg·kg⁻¹. The treated soils were incubated for 2 weeks and then dried at 20°C. For each soil sample and at each soil Cu concentration, the adsorption of λ-CHT and CPM was measured using a batch equilibrium method. The concentration of λ-CHT was determined by HPLC, and the amount of λ-CHT and CPM adsorbed by the soil sample at equilibrium was determined by the difference between the initial and equilibrium concentrations in solution corrected by the blank adsorption measurement. Results Without the addition of Cu, the adsorption of λ-CHT and CPM on Black soil is greater than that on Red soil, while the adsorption of λ-CHT on both soils is significantly stronger than that of CPM. As the soil Cu concentration increased from 19 (or 18; background) to 1,600 mg·kg⁻¹, the adsorption coefficient (K d) of λ-CHT decreased from 12.2 to 5.9 L·kg⁻¹ for Red soil, and from 26.1 to 16.8 L·kg⁻¹ for Black soil, whereas the CPM adsorption coefficient in both soils decreased nearly by 100% (K d decreased from 9.4 to 0.2 L·kg⁻¹ for Red soil and from 16.2 to 0.5 L·kg⁻¹ for Black soil). Discussion Pys adsorption is a surface phenomenon which depends on the surface area and the organic matter content. Thus, the Black soil, having higher organic matter and greater surface area than that of the Red soil, show greater adsorption affinity to λ-CHT and CPM. In our study, the different adsorption affinity of the two Pys was obtained, which was probably attributed to differences with respect to their physical-chemical properties. Further comparison upon the two Pys was conducted. The point charges of halogen atoms in the λ-CHT and CPM were calculated, the differences of which probably lead to the fact that λ-CHT has a stronger binding capacity to soils than CPM. Also, FTIR spectra show that competitive adsorption occurs between CPM and Cu for the same adsorption sites, which is responsible for the obtained suppression of CPM adsorption affected by Cu. Conclusions Lambda-cyhalothrin shows a significantly stronger adsorption than cypermethrin on both soils. This phenomenon may be due to several reasons: (1) λ-CHT has lower solubility and a higher octanol-water partition coefficient value than CPM; (2) λ-CHT consists of specific isomers, whereas CPM is mixtures of eight different isomers; (3) the chlorine and fluorine atoms in the λ-CHT have a negative point charge, whereas the chlorine atoms in the CPM have a positive point charge. As the soil Cu concentrations increased from 19 (or 18) mg·kg⁻¹ to 1,600 mg·kg⁻¹, the adsorption coefficient of λ-CHT and CPM decreased on both soils. This is mainly due to a competition between Cu and Pys for occupying the adsorption sites on soils. The information from this study have important implications for vineyard and orchard soils, which often contain elevated levels of Cu and Pys. These results are also useful in assessing the environmental fate and health effect of λ-CHT and CPM. Recommendations and perspectives It is important for environmental scientists and engineers to get a better understanding of soil-metal-organic contaminant interactions. However, pesticide adsorption involves complex processes, and shortcomings in understanding them still restrict the ability to predict the fate and behavior of pesticide. Therefore, considerable research should be carried out to understand the mechanism of interaction between Pys and heavy metal on soils clearly.
Показать больше [+] Меньше [-]The occurrence of antihistamines in sewage waters and in recipient rivers
2009
Kosonen, Jussi | Kronberg, Leif
Background, aim and scope Each year, large quantities of pharmaceuticals are consumed worldwide for the treatment and prevention of human and animal diseases. Although the drugs and the metabolites observed in the wastewaters and in the environment are present at concentrations several orders of magnitude lower than the concentrations required to exert their effects in humans or animals, their long-term impact on the environment is commonly not known. In this study, the occurrence of six antihistamines, which are used for the relief of allergic reactions such as hay fever, was determined in sewage treatment plants wastewaters and in recipient river waters. Materials and methods The occurrence of the antihistamines cetirizine, acrivastine, fexofenadine, loratadine, desloratadine and ebastine in sewage treatment plants wastewaters and in recipient river waters was studied. The analytical procedure consisted of solid-phase extraction of the water samples followed by liquid chromatography separation and detection by a triple-quadrupole mass spectrometer in the multiple reaction mode. Results Cetirizine, acrivastine and fexofenadine were detected in both influent and effluent wastewater samples at concentration levels ranging from about 80 to 220 ng/L, while loratadine, desloratadine and ebastine could not be detected in any samples. During sewage treatment, the concentration of the antihistamines dropped by an average of 16-36%. Furthermore, elevated concentrations of antihistamines were observed in samples collected during the season of most intensive plant pollen production, i.e. in May. In the river water samples, the relative pattern of occurrence of cetirizine, acrivastine and fexofenadine was similar to that in the wastewater samples; although the concentration of the compounds was substantially lower (4-11 ng/L). The highest concentrations of the studied drugs were observed near the discharging point of the sewage treatment plant. Discussion The highest concentrations of antihistamines in STP wastewaters correlate with the outbreak of allergic reaction caused by high amounts of plant pollens in the air. The analysis results of the river water samples show that the antihistamines are carried far away from the effluent discharge points. They may account for a part of the mix of pharmaceuticals and of pharmaceutical metabolites that occur downstream of STPs. Conclusions Antihistamines are poorly degraded/eliminated under the biological treatment processes applied in the wastewater treatment plants and, consequently, they are continuously being discharged along with other drugs to the aquatic environment. Recommendations and perspectives As a huge quantity and variety of drugs and their metabolites are continuously discharged to rivers and the sea, the compounds should be considered as contaminants that may possess risks to the aquatic ecosystem. Further studies are urgently needed on the environmental fate of the antihistamines and other pharmaceuticals in the aquatic environment. These studies should be concerned with the stability of the compounds, their transformation reactions and the identity of the transformation products, the distribution of drugs and their uptake and effects in organisms. On the basis of these studies, the possible environmental hazards of pharmaceuticals may be assessed.
Показать больше [+] Меньше [-]The astysphere and urban geochemistry--a new approach to integrate urban systems into the geoscientific concept of spheres and a challenging concept of modern geochemistry supporting the sustainable development of planet earth
2009
Norra, Stefan
Background, aim, and scope In 1875, the geoscientist Walter Suess introduced several spheres, such as the lithosphere and the atmosphere to promote a comprehensive understanding of the system earth. Since then, this idea became the dominating concept for the understanding of the distribution of chemical elements in the system earth. Meanwhile, due to the importance of human beings on global element fluxes, the term anthroposphere was introduced. Nevertheless, in face of the ongoing urbanization of the earth, this concept is not any more adequate enough to develop a comprehensive understanding of global element fluxes in and between solid, liquid, and gaseous phases. This article discusses a new concept integrating urbanization into the geoscientific concept of spheres. Main features No geological exogenic force has altered the earth's surface during the last centuries in such an extent as human activity. Humans have altered the morphology and element balances of the earth by establishing agrosystems first and urban systems later. Currently, urban systems happen to become the main regulators for fluxes of many elements on a global scale due to ongoing industrial and economic development and a growing number of inhabitants. Additionally, urban systems are constantly expanding and cover more and more former natural and agricultural areas. For nature, urban systems are new phenomena, which never existed in previous geological eras. The process of the globe's urbanization concurrently is active with the global climate change. In fact, urban systems are a major emitter for climate active gases. Thus, beside the global changes in economy and society, urbanization is an important factor within the global change of nature as is already accepted for climate, ecosystems, and biodiversity. Results Due to the fact that urbanization has become a global process shaping the earth and that the urban systems are globally cross-linked among each other, a new geoscientific sphere has to be introduced: the astysphere. This sphere comprises the parts of the earth influenced by urban systems. Accepting urbanization as global ongoing process forming the astysphere comprehensively copes with the growing importance of urbanization on the creation of present geologic formations. Discussion Anthropogenic activities occur mainly in rural and urban environments. For long lasting periods of human history, human activities mainly were focused on hunting and agriculture, but since industrialization, urbanized areas became increasingly important for the material and energy fluxes of earth. Thus, it seems appropriate to classify the anthroposphere into an agriculturally and an urban-dominated sphere, which are the agrosphere (Krishna 2003) and the astysphere (introduced by Norra 2007). Conclusions We have to realize that urban systems are deposits, consumers, and transformers of resources interacting among each other and forming a network around the globe. Since the future of human mankind depends on the sustainable use of available resources, only a global and holistic view of the cross-linked urban systems forming together the astysphere provide the necessary geoscientific background understanding for global urban material and energy fluxes. If we want to ensure worth-living conditions for future generations of mankind, we have to develop global models of the future needs for resources by the global metasystem of urban systems, called astysphere. Perspectives The final vision for geoscientific research on the astysphere must be to design models describing the global process of urbanization of the earth and the development of the astysphere with respect to fluxes of materials, elements, and energy as well as with respect to the forming of the earth's face. Besides that, just from the viewpoint of fundamental research, the geoscientific concept of spheres has to be complemented by the astysphere if this concept shall fully represent the system earth.
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