Detoxification of ferrocyanide in asoil–plant system

The detoxification of iron cyanide in a soil–plant system was investigated to assess the total cyanide extracted from contaminated soil and allocated in the leaf tissue of willow trees(Salix caprea). They were grown in soil containing up to 1000 mg/kg dry weight(dw) of cyanide(CN),added as ~(15)N-labeled potassium ferrocyanide and prepared with a new method for synthesis of labeled iron cyanides. CN content and ~(15)N enrichment were monitored weekly over the exposure in leaf tissue of different age. The ~(15)N enrichment in the young and old leaf tissue reached up to 15.197‰ and 9063‰, respectively; it increased significantly over the exposure and with increasing exposure concentrations(p 0.05). Although the CN accumulation in the old leaf tissue was higher, compared to the young leaf tissue(p 0.05), the ~(15)N enrichment in the two tissue types did not differ statistically. This indicates a non-uniform CN accumulation but a uniform ~(15)N allocation throughout the leaf mass. Significant differences were detected between the measured CN content and the C~(15)N content, calculated from the ~(15)N enrichment(p 0.05), revealing a significant CN fraction within the leaf tissue, which could not be detected as ionic CN. The application of labeled iron CN clearly shows that CN is detoxified during uptake by the willows. However, these results do not exclude other detoxification pathways, not related to the trees. Still, they are strongly indicative of the central role the trees played in CN removal and detoxification under the experimental conditions.     

Model simulations for describing water transport in a landfill with bottom ash from a municipal solid waste incinerator (MSWI): model validation and scenarios.

In the present study the water movement in a bottom ash landfill from a municipal solid waste incinerator (MSWI) was investigated. The pore regime of such landfills consists of macropores (with diameter > 50 microm), which make up about two-thirds of the total porosity and micropores. The program MACRO, which describes flow through porous media and takes both macro- and micropore flows into account, was applied. The model was calibrated with a time series from the landfill Riet, near Winterthur in Switzerland. In the present study the model was recalibrated at a time series for 1 year. With this scenario the influence of an expected reduction or increase of the porosity on leachate behaviour of such landfills over a long time (> 100 years) was studied ('long-term behaviour'). It has been shown that reliable information about water percolation can only be provided by obtaining more information about the hydraulic structure of such landfills. In particular, the number of macropores and the porosity exert great influence on the water movement.     

Biodynamics of steering wheel induced facial trauma

The present study was undertaken to determine the impact biomechanics of the facial skeleton secondary to steering wheel loading. Because of the particular relevance of the zygomatic bony complex in facial trauma during motor-vehicle accidents, tests were conducted by impacting the zygoma using a vertical drop impact test system. Zygoma was impacted once onto either soft or rigid wheel surfaces at velocities of up to 6.7 m/s. Peak impact forces at the cadaver zygoma were computed from the generalized force and deformation histories using matrix transformation principles. Structural abnormalities were assessed using pre- and post-test plain radiography, two-and three-dimensional computed tomography, and defleshing techniques. At impact velocities of 1.7 to 6.7 m/s, the human cadaver zygoma did not exhibit clinically significant fractures if the peak force was below 1335 N for the soft wheel interface and 1153 N for the rigid wheel interface. Consequently, to mitigate facial injuries due to unsupported rim impact, the data from the present study suggests that the peak dynamic force should be kept within these limits.     

Integrating economic costs into the analysis of flexible conservation management strategies.

Flexible conservation management, where measures (e.g., mowing of meadows, removing invasive species) are selected in each decision period depending on the current state of the ecological system, is generally perceived as superior to fixed management, where the same measure is applied in each decision period independent of the current state of the system. In past comparisons of fixed and flexible conservation strategies the additional costs that arise only in flexible strategies have usually been ignored. In this paper, we present a framework to integrate costs of flexible management into the evaluation of flexible conservation strategies. Using the example of an endangered butterfly species we demonstrate that the costs of flexible management may reverse the rank order of flexible and fixed conservation strategies, such that fixed strategies may lead to better ecological results than flexible ones for the same financial budget.     

Chorionic villi sampling changes maternal serum alpha-fetoprotein

Second trimester amniocentesis has traditionally been utilized for prenatal genetic diagnosis. Chorionic villi sampling (CVS) is presently offered as an alternative. The occurrence of fetomaternal bleed (FMB) during CVS could increase the rate of post sampling abortion and, additionally, be of significance in patients at risk for isoimmunization. Detection and quantitation of FMB can be accomplished by the determination of changes in maternal serum alpha-fetoprotein (MSAFP) before and after CVS.     

Parameterizing,evaluating and comparing metapopulation models with data from individual-based simulations

Due to the lack of sufficient data and appropriate ecological information parameterizing predictive population dynamical models usually is a difficult task. The approach proposed in this study is meant to overcome this problem by using detailed individual-based simulations to generate artificial data. With short-term data samples, the models to be investigated can be parameterized and their predictions be compared. The flexibility of individual-based simulations as experimental tools also facilitates the evaluation and comparison of different (aggregated) model types. The presented approach is a step towards unifying models of different complexity. As an example we applied it to two metapopulation models of insect species in a highly fragmented landscape: the well-known incidence function model with a patch-based representation of space and a grid-based analogue. The models are tested with respect to their data requirement and recommendations for a better data sampling are derived.     

A risk-based screening approach for prioritizing contaminants and exposure pathways at Superfund sites

Contamination at Superfund sites can involve mixtures of chemicals and radionuclides in a variety of environmental media. Determining priorities for evaluation and remediation of various contaminants is an important part of the initial phases of any site investigation. An effective screening analysis at the beginning of the project can help by identifying both those situations in need of immediate remedial attention and those which require further sampling and evaluation. The screening approach discussed here is made up of two sets of calculations designed to provide upper- and lower-bound estimates of health risk to individuals likely to receive the highest exposures. This approach allows rapid identification of contaminants which pose a negligible risk and can be assigned a low priority for remedial attention or which pose a substantial risk and should be given the highest priority for appropriate remediation efforts. Contaminants designated as neither high- nor low-priority should be investigated in more detail prior to making decisions regarding the need for or method of remediation. The utility of this approach has already been demonstrated in the evaluation of contamination in the Clinch and Tennessee River systems originating from historical operations of atomic weapons and energy research facilities near Oak Ridge, Tennessee.