Ökotoxikologische und humantoxikologische Risikobewertung PAK-belasteter Böden vor und nach biologischer Behandlung

The goal of the present work is to assess the adverse effects of soil bound polycyclic aromatic hydrocarbons (PAH) which remain in soils after biological remediation. We focus on risk assessment for mammalian species with respect to the oral uptake of contaminated soil particles and compare the results of a biomarker test with those of an ecotoxicological assay, the bioluminescence inhibition test withVibrio fischeri. As a biomarker effect in mammals, we determined the liver microsomal cytochrome P450 enzyme CYP1A1 which is induced by PAH in exposed rats. After biological soil treatment, different amounts of PAH remain in the soil depending on the soil properties and initial pollutant composition. Particularly, higher condensated PAH resists biological treatment due to its hydrophobicity. In addition, high amounts of organic carbon in the soils affect remediation efficiency. In the bioluminescence inhibition test, eluates of all biologically treated soils studied do not reveal any or only low inhibitory effects. In contrast, the oral uptake of biologically treated contaminated soils leads to induction levels for CYP1A1 similar to those in the untreated samples. A good correlation is obtained between CYP1A1 levels and the amount of 5 and 6-ring PAH in the soil samples. The main result is that the remediation efficiency determined by the luminescence test is not reflected by the biomarker test, a finding which indicates the high bioavailability of residual PAH in soils. Consequently, new criteria for human risk assessment can be delineated.     

温带典型草地土壤净氮矿化作用研究

应用树脂芯方法,研究了内蒙古锡林河流域不同降水强度3种草地类型土壤净氮矿化作用.结果表明,7～10月份,羊草草原的平均净氮矿化率为0.333 kg·(hm²·d)^-1,贝加尔针茅草原为0.316 kg·(hm²·d)^-1,克氏针茅草原为0.211 kg·(hm²·d)^-1;在相同的培养周期内,分阶段培养和连续培养对土壤的净氮矿化量和净氮矿化速率有显著影响;降雨是影响该区域氮素矿化的主要因素之一,3种草地类型土壤水分变化量与土壤净氮矿化速率呈正相关关系,相关系数分别为0.80、0.61、0.56.     

Optimal foraging: The influence of intraspecific competition on diet selection

Summary Three-spined sticklebacks (Gasterosteus aculeatus) showed a relative preference for a familiar prey size when hunting for two sizes of Daphnia magna in high density. This result is not compatible with the apparent size hypothesis. Ten groups were investigated, each consisting of two stickle-backs tested under three consecutive experimental conditions, to establish whether the function of the preference for a familiar prey size could be avoidance of competition.First, the relative competitive ability of each fish was determined by the proportion it consumed of three series of 60 medium-sized daphnia, offered pairwise. Second, during the consumption of five series of 30 pairs, each consisting of a large and a small daphnia, it was determined how many items each fish caught of each prey size. As handling times were equal for both prey types, the larger prey size was more profitable. There was a significant correlation between relative competitive ability and mean proportion of large daphnia in the diet. In the last series the less successful competitiors caught a higher proportion of small prey than in the first series. Finally, each fish was given the choice between large and small daphnia in the absence of its competitor. The sticklebacks chose a diet similar to the one they had been allowed to select previously with competition. The previously more successful competitors concentrated on large daphnia, whereas the poorer competitors fed as generalists but not unselectively.The fish probably learned the distance from which they had recently attacked familiar prey successfully. This sure attack distance depends on the fish's competitive ability.     

The use of the tergal gland defensive secretion in male intrasexual aggression of the rove beetle,Aleochara curtula (Coleoptera: Staphylinidae), measured by closed-loop-stripping-analyses and tandem bioassay — mass fragmentography

Summary 2-methyl-1,4-benzoquinone as a target compound of the tergal gland secretion of the rove beetle,Aleochara curtula, was quantified from the reservoirs of individual beetles. Males store less secretion than females, and they evaporate more of the secretion as measured by adsorption from the air (closed-loop-stripping-analysis). The amount of emitted quinone is increased during aggressive interactions of rival males. The pulsed emission of the secretion during aggression is demonstrated by a novel technique combining observation of behavior with the on-line measurement of target fragment ions by mass-spectrometry (tandem bioassay — mass fragmentography). The emission of the secretion is used as a weapon in combats between males and may result in the repulsion of subordinate males from the mating site, but may also serve to mimic females chemically in order to avoid aggressive encounters.     

Welche Aussichten bietet das Berginverfahren für die deutsche Ölversorgung?

The Science of Nature -     

Ozone measurements along vertical transects in the Alps

To investigate the vertical profiles of air pollutants in the boundary layer, aircraft and balloon-born measurements and measurements using a cable car as an instrument platform have been performed in different parts of the Alps. This on-line monitoring of atmospheric pollutants requires expensive and sophisticated techniques. In order to control ambient air quality in remote regions, where no infrastructure like power supply is available, simple instruments are required. The objective of this study, which was coordinated and evaluated by the GSF-Forschungszentrum für Umwelt und Gesundheit was first, to investigate the vertical distribution of ozone in different parts of the Alps and secondly, in addition to continuous analyser measurements, to test monitoring by means of two types of passive samplers. The selection of these samplers — one for one week use and another one for two week application — was based on a passive sampler intercomparison done in a preliminary study one year earlier.