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81.
Abstract

The urea herbicide buturon (N‐[p‐chlorophenyl] ‐N’ ‐methyl‐N’ ‐isobutinyl‐urea), 14C‐labeled, was sprayed on winter wheat as an aqueous formulation (2.98 kg/ha) under outdoor conditions. Upon harvest (three months after application), a total of 49. 2% of the applied radiocarbon was recovered: 2.0% in the plants, 46.9% in the soil, and 0.3% in the leaching water (depth > 50 cm); less than 0.1% was in the grains (0.464 ppm). Only about half of the radioactivity present in plants could be recovered under mild extraction conditions; about half of this was unchanged buturon. In straw and husk extracts, the following metabolites were identified by gaschromatography/mass spectrometry: N‐(p‐chlorophenyl)‐N‐methyl‐O‐methyl‐carbamate (metabolite I), N‐phenyl‐N’ ‐formyl‐urea (metabolite II), two unstable metabolites giving (p‐chlorophenyl)‐isocyanate upon purification (metabolites III and IV), N‐(p‐chlorophenyl)‐N’ ‐methyl‐N’ ‐isobutenylol‐urea (metabolite V), p‐chloroformanilide (metabolite VI) and biologically bound p‐chloroaniline (metabolite VII). In the root and basal stem extract, the following metabolites were identified by gas chromatography/mass spectrometry: N‐(p‐chlorophenyl)‐O‐methyl‐carbamate (metabolite VIII) and N‐(p‐chlorophenyl)‐N’ ‐methyl‐urea (metabolite IX).  相似文献   
82.
In Europe, 9.3 x 10(6) t(dry weight (dw)) of compost and digestate are produced per year. Most of this is applied to agricultural land, which can lead to considerable inputs of organic pollutants, such as polychlorinated biphenyls (PCB) and polycyclic aromatic hydrocarbons (PAH) to soil. This paper presents an inventory of the pollutant situation in source-separated composts, digestates and presswater in Switzerland by a detailed analysis of over 70 samples. PCB concentrations ( summation PCB 28, 52, 101, 118, 138, 153, 180) were significantly higher in urban (median: 30 microg kg(-1)dw, n = 52) than in rural samples (median: 14 microg kg(-1)dw, n = 16). Together with low concentrations in general, this points to aerial deposition on compost input material as the major contamination pathway. Enantiomeric fractions of atropisometric PCB were close to racemic. Median PAH concentration was 3010 microg kg(-1)dw( summation 15PAH, n = 69), and one quarter of the samples exhibited concentrations above the relevant Swiss guide value for compost (4000 microg kg(-1)dw). The levels were influenced by the treatment process (digestate > compost), the season of input material collection (spring-summer > winter > autumn), the particle size (coarse-grained > fine-grained), and maturity (mature > less mature). The main source of PAH in compost was pyrogenic, probably influenced mainly by liquid fossil fuel combustion and some asphalt abrasion, as suggested by multiple linear regression. This study, together with a companion paper reporting on other organic contaminates including emerging compound classes, provides a starting point for a better risk-benefit estimation of the application of compost and digestate to agricultural soil in Switzerland.  相似文献   
83.
84.
In December 2009 the German Research Foundation published the booklet "Grüne Gentechnik" (Genetically modified crops) claiming to give a scientifically well balanced information about GMO's in agriculture. In this paper we analyse this approach resulting in a critical review regarding the intention of the booklet. We conclude that the evaluation of GMO's in agriculture primarily from a crop breeding perspective is lacking crucial positions in terms of ecology, socio-economy, agronomy, nutritional sciences and finally ethics in life science.  相似文献   
85.
Uran in Wässern     
The study presents 172 measurements of the uranium238U and234U isotopes in ground water and 21 measurements of these substances in the rivers of Eastern Germany. The uranium concentration in the ground water ranged from under 0.1 mBq/l to over 1000 mBg/l with a mean of 12 mBq/l. The respective activity relationships of234U/238U ranged from 0.85 to 12.6 with a mean of 1.66. A comparison of these values with those in the literature demonstrates an agreement with more recent measurements obtained from water in Thuringia and Saxony which were seen to have a mean value of 19 mBq/l. The activity relationships of234U/238U which were seen to be substantially over the equilibrial value of 1.0 and which were found in a quite high proportion of the samples must be taken into consideration when evaluating these. The measurements of river water demonstrated values for the Elbe river which are related to the periods of extensive uranium mining in Saxony and Thuringia. Measurements performed in the catchment regions going into the Baltic Sea revealed substantially higher values than would be expected from the distribution of uranium in these areas. A number of reasons are discussed here in an attempt to explain these findings.  相似文献   
86.
87.
This paper describes the statistical methodology applied to evaluate the performance of the long-range dispersion models that were used in the modelling activities of ETEX (European Tracer EXperiment). The availability of a large number of models makes this exercise rather unique. These models are used for the practical purpose to quantify the contamination effects over a vast area, following a hypothetical accidental release of harmful material. This makes the quality judgement that could be attributed to the results of each model particularly important.The statistical indicators considered to be the most effective for the evaluation of long-range dispersion models are introduced and commented, with specific examples in the frame of ETEX simulations. The importance of using several indices and critically interpreting the results is discussed.  相似文献   
88.
This paper reviews the role of minerals in the Integrated Programme for Commodities and the objectives and problems of the Second Account of the Common Fund for Commodities (CFC). It focuses on the least developed countries in Africa, providing specific suggestions for R&D to improve mineral exploration techniques in rain forest and savanna regions; to reduce mine exploration costs; to design equipment suitable for mining narrow veins; to improve concentrating methods for certain ores and to optimize byproduct recovery; to reduce environmental impacts; and to use the waste products of mining. It also discusses demand oriented CFC projects and their policy implications.  相似文献   
89.
Summary Young chicks were offered a choice of warningly coloured black and yellow and non-warningly coloured green (or olive) prey. Unfed chicks were given palatable painted mealworms on their first day. They directed their first peck at both colour types at the same probability; however, they ate the warningly coloured ones at a much lower rate. This is due to an inhibition of attack which becomes effective after pecking. Chicks which were a few days old showed the same behaviour. Since the control prey was in this case painted with an olive mixture containing the same colours as the warningly coloured mealworms, it can be concluded that the inhibition is caused by the black and yellow coloration. With accumulating positive experience of the chicks, the inhibition decreased. For permanent avoidance it must therefore be supplemented by unpleasant experience. Accordingly, chicks handled the unpalatable black and yellow ringed caterpillars of Tyria jacobaeae only a few times and always for a short period when offered repeatedly. The inhibition caused by the black and yellow pattern is attributed to a genetically fixed predisposition to avoid warningly coloured black and yellow prey which is the result of evolutionary adaptation.  相似文献   
90.
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