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481.
South Asia faces increasing flooding risks due to climatic and socio-economic changes. Various measures have been adopted by the governments of the countries in this region. However, these measures are not adequate to protect the vulnerable communities from ever-increasing flood losses. This study assesses the policy and planning processes and flood-related scientific research in India, Pakistan and Bangladesh. Based on a systematic review, a comparison of the existing flood management systems of the three countries is undertaken, and a framework for sustainable flood management in the region is suggested. Insights from the literature show that Bangladesh has been able to develop an effective governance structure to address flood hazards, while Pakistan’s approach to flood management planning is found to be largely inadequate. This inadequacy is mainly attributed to missing links in policy formulation and planning processes, along with a lack of institutional coordination. The results of the literature analysis reveal poor support from scientific research focusing on flooding issues in the case of Pakistan, while Bangladesh and India seem to have benefited from research support in formulating their flood management strategies. Based on these findings, an alternative framework is suggested, emphasizing the need to enhance institutional linkages, community participation and evidence-based research.  相似文献   
482.
In the public debate concerning novel foods, someconsumer groups claim a consumer right to have accessto certain kinds of food in the market. To discusssuch statements, the paper identifies the reasons thatmay justify liberal states to regulate food. Althoughit defends certain paternalistic activities, itfavours an autonomy-centred food policy. Autonomy andconsumer sovereignty require that certain conditionsare fulfilled. It may be argued that one suchcondition is that the consumer should have choices.Against this position, the paper defends the view thatliberty rights to choose are limited to areas whichare of great importance for personal identity and thegood life. Local decisions in the area of foodconsumption do not have such importance, though globalones may have it. But even if this were true,government activity to protect such liberties shouldbe limited to the guarantee of formal conditions forthe good life of persons. It is not a legitimate taskof the government to safeguard specific conceptions ofthe good life.  相似文献   
483.
484.
Angeborene Tagesperiodik bei Eidechsen   总被引:1,自引:0,他引:1  
  相似文献   
485.

Background, aim, and scope  

Anti-tumour agents and their metabolites are largely excreted into effluent, along with other pharmaceuticals. In the past, investigations have focused on the input and analysis of pharmaceuticals in surface and ground water. The two oxazaphosphorine compounds, cyclophosphamide and ifosfamide are important cytostatic drugs used in the chemotherapy of cancer and in the treatment of autoimmune diseases. Their mechanism of action, involving metabolic activation and unspecific alkylation of nucleophilic compounds, accounts for genotoxic and carcinogenic effects described in the literature and is reason for environmental concern. The anti-tumour agents cyclophosphamide (CP) and ifosfamide (IF) were not biodegraded in biodegradation tests. They were not eliminated in municipal sewage treatment plants. Degradation by photochemically formed HO radicals may be of some relevance only in shallow, clear, and nitrate-rich water bodies but could be further exploited for elimination of these compounds by advanced oxidation processes, i.e. in a treatment of hospital waste water. Therefore, CP and IF are assumed to persist in the aquatic environment and to enter drinking water via surface water. The risk to humans from input of CP and IF into surface water is not known.  相似文献   
486.
Letzel M  Weiss K  Schüssler W  Sengl M 《Chemosphere》2010,81(11):1416-1422
To investigate the occurrence and fate of ritalinic acid - the main human metabolite of the psychostimulant drug methylphenidate - in the aquatic environment, a HPLC-electrospray-MS/MS method for the quantification of ritalinic acid in wastewater, surface water and bank filtrate was developed. Carbamazepine known as very stable in the aquatic environment was analyzed as anthropogenic marker in parallel. Furthermore, the removal of ritalinic acid was studied in a sewage treatment plant using an activated sludge system during a field study and in lab-scale plants. In good agreement between lab-scale and field studies a low removal rate of 13% and 23%, respectively, was determined. As a consequence, the concentration of ritalinic acid in the wastewater effluents were in the range of <50-170 ngL(-1) which corresponds to a mean specific load per capita of 17.7 μgd(-1). Ritalinic acid has further been detected in German rivers at concentrations of 4-23 ngL(-1) and in bank filtrate samples in 100-850 m distance from the river up to 5 ngL(-1) demonstrating the widespread occurrence of this stable metabolite in the aquatic environment. A comparison to available sales data shows that a significant amount of methylphenidate applied can be found in waters as ritalinic acid.  相似文献   
487.
From September 2006 to October 2007 turbulent fluxes of carbon dioxide were measured at an urban tower station (26 m above ground level, z/zh = 1.73) in Essen, Germany, using the eddy covariance technique. The site was located at the border between a public park area (70 ha) in the south–west of the station and suburban/urban residential as well as light commercial areas in the north and east of the tower. Depending on the land-use two different sectors (park and urban) were identified showing distinct differences in the temporal evolution of the surface-atmosphere exchange of CO2. While urban fluxes appear to be governed by anthropogenic emissions from domestic heating and traffic (average flux 9.3 μmol m?2 s?1), the exchange of CO2 was steered by biological processes when the park contributed to the flux footprint. The diurnal course during the vegetation period exhibited negative daytime fluxes up to ?10 μmol m?2 s?1 on average in summer. Nevertheless, with a mean of 0.8 μmol m?2 s?1 park sector fluxes were slightly positive, thus no net carbon uptake by the surface occurred throughout the year.In order to sum the transport of CO2 a gap-filling procedure was performed by means of artificial neural network generalisation. Using additional meteorological inputs the daily exchange of CO2 was reproduced using radial basis function networks (RBF). The resulting yearly sum of 6031 g m?2 a?1 indicates the entire study site to be a considerable source of CO2.  相似文献   
488.

Purpose

Ciprofloxacin (CIP), a broad-spectrum, second-generation fluoroquinolone, has frequently been found in hospital wastewaters and effluents of sewage treatment plants. CIP is scarcely biodegradable, has toxic effects on microorganisms and is photosensitive. The aim of this study was to assess the genotoxic potential of CIP in human HepG2 liver cells during photolysis.

Methods

Photolysis of CIP was performed in aqueous solution by irradiation with an Hg lamp, and transformation products were monitored by HPLC-MS/MS and by the determination of dissolved organic carbon (DOC). The cytotoxicity and genotoxicity of CIP and of the irradiated samples were determined after 24?h of exposure using the WST-1 assay and the in vitro micronucleus (MN) test in HepG2 cells.

Results

The concentration of CIP decreased during photolysis, whereas the content of DOC remained unchanged. CIP and its transformation products were not cytotoxic towards HepG2 cells. A concentration-dependent increase of MN frequencies was observed for the parent compound CIP (lowest observed effect level, 1.2???mol?L?1). Furthermore, CIP and the irradiated samples were found to be genotoxic with a significant increase relative to the parent compound after 32?min (P?P?Conclusions Photolytic decomposition of aqueous CIP leads to genotoxic transformation products. This proves that irradiated samples of CIP are able to exert heritable genotoxic effects on human liver cells in vitro. Therefore, photolysis as a technique for wastewater treatment needs to be evaluated in detail in further studies, not only for CIP but in general.  相似文献   
489.
Many pharmaceuticals and related metabolites are not efficiently removed in sewage treatment plants and enter into surface water. There, they might be subject of drinking water abstraction and treatment by ozonation. In this study, a systematic approach for producing and effect-based testing of transformation products (TPs) during the drinking water ozonation process is proposed. For this, two pharmaceutical parent substances, three metabolites and one environmental degradation product were investigated with respect to their biodegradability and fate during drinking water ozonation. The Ames test (TA98, TA100) was used for the identification of mutagenic activity present in the solutions after testing inherent biodegradability and/or after ozonation of the samples. Suspicious results were complemented with the umu test. Due to the low substrate concentration required for ozonation, all ozonated samples were concentrated via solid phase extraction (SPE) before performing the Ames test. With the exception of piracetam, all substances were only incompletely biodegradable, suggesting the formation of stable TPs. Metformin, piracetam and guanylurea could not be removed completely by the ozonation process. We received some evidence that technical TPs are formed by ozonation of metformin and piracetam, whereas all tested metabolites were not detectable by analytical means after ozonation. In the case of guanylurea, one ozonation TP was identified by LC/MS. None of the experiments showed an increase of mutagenic effects in the Ames test. However, the SPE concentration procedure might lead to false-positive results due to the generation of mutagenic artefacts or might lead to false-negative results by missing adequate recovery efficiency. Thus, these investigations should always be accompanied by process blank controls that are carried out along the whole ozonation and SPE procedure. The study presented here is a first attempt to investigate the significance of transformation products by a systematic approach. However, the adequacy and sensitivity of the methodology need to be further investigated. The approach of combining biodegradation and ozonation with effect-based assays is a promising tool for the early detection of potential hazards from TPs as drinking water contaminants. It can support the strategy for the evaluation of substances and metabolites in drinking water. A multitude of possible factors which influence the results have to be carefully considered, among them the selectivity and sensibility of the mutagenicity test applied, the extraction method for concentrating the relevant compounds and the biocompatibility of the solvent. Therefore, the results have to be carefully interpreted, and possible false-negative and false-positive results should be considered.  相似文献   
490.
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