Документи Державного архіву Чернігівської області як джерело захисту прав жертв нацистського окупаційного режиму

The retention of phosphorus in surface waters through co-precipitation of phosphate with Fe-oxyhydroxides during exfiltration of anaerobic Fe(II) rich groundwater is not well understood. We developed an experimental field set-up to study Fe(II) oxidation and P immobilization along the flow-path from groundwater into surface water in an agricultural experimental catchment of a small lowland river. We physically separated tube drain effluent from groundwater discharge before it entered a ditch in an agricultural field. Through continuous discharge measurements and weekly water quality sampling of groundwater, tube drain water, exfiltrated groundwater, and surface water, we investigated Fe(II) oxidation kinetics and P immobilization processes. The oxidation rate inferred from our field measurements closely agreed with the general rate law for abiotic oxidation of Fe(II) by O₂. Seasonal changes in climatic conditions affected the Fe(II) oxidation process. Lower pH and lower temperatures in winter (compared to summer) resulted in low Fe oxidation rates. After exfiltration to the surface water, it took a couple of days to more than a week before complete oxidation of Fe(II) is reached. In summer time, Fe oxidation rates were much higher. The Fe concentrations in the exfiltrated groundwater were low, indicating that dissolved Fe(II) is completely oxidized prior to inflow into a ditch. While the Fe oxidation rates reduce drastically from summer to winter, P concentrations remained high in the groundwater and an order of magnitude lower in the surface water throughout the year. This study shows very fast immobilization of dissolved P during the initial stage of the Fe(II) oxidation process which results in P-depleted water before Fe(II) is completely depleted. This cannot be explained by surface complexation of phosphate to freshly formed Fe-oxyhydroxides but indicates the formation of Fe(III)-phosphate precipitates. The formation of Fe(III)-phosphates at redox gradients seems an important geochemical mechanism in the transformation of dissolved phosphate to structural phosphate and, therefore, a major control on the P retention in natural waters that drain anaerobic aquifers

New linear plasma devices in the trilateral euregio cluster for an integrated approach to plasma surface interactions in fusion reactors

New linear plasma devices are currently being constructed or planned in the Trilateral Euregio Cluster (TEC) to meet the challenges with respect to plasma surface interactions in DEMO and ITER: i) MAGNUM-PSI (FOM), a high particle and power flux device with super-conducting magnetic field coils which will reach ITER-like divertor conditions at high magnetic field, ii) the newly proposed linear plasma device JULE-PSI (FZJ), which will allow to expose toxic and neutron activated target samples to ITER-like fluences and ion energies including in vacuo analysis of neutron activated samples, and iii) the plasmatron VISION I. a compact plasma device which will be operated inside the tritium lab at SCK-CEN Mol, capable to investigate tritium plasmas and moderately activated wall materials. This contribution shows the capabilities of the new devices and their forerunner experiments (Pilot-PSI at FOM and PSI-2 Julich at FZJ) in view of the main objectives of the new TEC program on plasma surface interactions. (C) 2011 Forschungszentrum Julich, Institut fur Energieforschung-Plasmaphysik. Published by Elsevier B.V. All rights reserved

Comparative population genetic structure of the endangered southern brown bandicoot, Isoodon obesulus, in fragmented landscapes of Southern Australia

Genetic connectivity is a key factor for maintaining the persistence of populations in fragmented landscapes. In highly modified landscapes such us peri-urban areas, organisms' dispersal among fragmented habitat patches can be reduced due to the surrounding matrix, leading to subsequent decreased gene flow and increased potential extinction risk in isolated sub-populations. However, few studies have compared within species how dispersal/gene flow varies between regions and among different forms of matrix that might be encountered. In the current study, we investigated gene flow and dispersal in an endangered marsupial, the southern brown bandicoot (Isoodon obesulus) in a heavily modified peri-urban landscape in South Australia, Australia. We used 14 microsatellite markers to genotype 254 individuals which were sampled from 15 sites. Analyses revealed significant genetic structure. Our analyses also indicated that dispersal was mostly limited to neighbouring sites. Comparisons of these results with analyses of a different population of the same species revealed that gene flow/dispersal was more limited in this peri-urban landscape than in a pine plantation landscape approximately 400 km to the south-east. These findings increase our understanding of how the nature of fragmentation can lead to profound differences in levels of genetic connectivity among populations of the same species.You Li, Steven J.B. Cooper, Melanie L. Lancaster, Jasmin G. Packer, Susan M. Carthe

Geochemical and hydrodynamic phosphorus retention mechanisms in lowland catchments

The release of phosphorus (P) to surface water from heavily fertilised agricultural fields is of major importance for surface water quality. The research reported in this thesis examined the role of geochemical and hydrodynamic processes controlling P speciation and transport in lowland catchments in the Netherlands. This study showed that the mobility and ecological impact of P in surface waters in lowland catchments or polders like those in the Netherlands are strongly controlled by the exfiltration of anoxic groundwater containing ferrous iron. Results of an experimental field set-up showed showed that the formation of Fe precipitates upon oxygenation of anaerobic Fe-bearing groundwater is a key process affecting the P speciation in surface waters in lowland catchments. We found that Fe oxidation rates are much slower in winter than in summer, but that removal of P by oxidising Fe(II) was highly efficient in both seasons, resulting in low dissolved P concentrations in the surface water throughout the year. Our observations cannot be explained by surface complexation of PO4 to freshly formed Fe oxyhydroxides but indicates that Fe(III) phosphate precipitates are formed preferentially. In a series of aeration experiments, we explored the relationship between solution composition, reaction kinetics and the characteristics of the produced Fe(III) precipitates. The aeration experiments with Fe(II)-containing solutions demonstrated that dissolved PO4 can be effectively immobilised in the form of a homogeneous Fe hydroxyphosphate. Fe(II) oxidation was generally slower in the presence of PO4 than in the absence of PO4, but the decrease of the PO4 concentration during Fe(II) oxidation due to the formation of Fe hydroxyphosphates retarded the reaction rate even more. The progress of the Fe(II) oxidation reaction could be described using a pseudo-second-order rate law with first-order dependencies on PO4 and Fe(II) concentrations. The results from the field and laboratory experiments were confirmed with data from field surveys in catchments. We showed that the suspended particulate matter (SPM) sampled during various conditions in six lowland catchments in the Netherland had high P contents. The average content was about 2-10 higher than the P contents of SPM reported in international studies. Iron-bound P was, with an average value of 61%, the dominant P species in the TP concentration in surface water bodies in the lowland catchments. After the turnover of dissolved P to iron-bound particulate P, transport of P in catchments or polders is controlled by sedimentation and erosion of particles. Hydrodynamic resuspension of P stored in bed sediments is commonly considered as being the main transport mechanism in lowland catchments. A combination of erosion experiments with undisturbed bed sediment cores and a hydrodynamic model that calculates bed shear stresses in water courses revealed contrasting insights for polder catchments. Polder catchments typically have a dense network of drainage ditches and a water flow strongly controlled by weirs and pumping stations. This geographic setting tempers peak flow and thus results in lower maximum hydrodynamic forces that generally may not be strong enough to cause erosion of bed sediment

Regional monitoring of temporal changes in groundwater quality

Changes in agricultural practices are expected to affect groundwater quality by changing the loads of nutrients and salts in recharging groundwater, but regional monitoring networks installed to register the changes often fail to detect them and interpretation of trend analysis results is difficult. This study aims to improve the detection and understanding of groundwater quality changes with time, combining time series information, concentration-depth profiles, age dating and concentration-depth prognoses based on the historical inputs of solutes. For trend detection, a combination of trend analysis on time series at specific depths and time-averaged concentration-depth profiles was used. To reveal trends that have become obscured by chemical reactions, additional conditionally conservative indicators were introduced that are insensitive to those reactions under specific conditions. Detected trends were matched with prognoses of conservative and reactive transport to aid the understanding of trends. Data of the regional networks in 2 area-types with intensive livestock farming in the Dutch province of Noord-Brabant were used to illustrate the approach. The downward movement of the agricultural pollution front was demonstrated for the 2 area-types. However, many targeted contaminants have become retarded or delayed and quality changes were hard to detect for many reactive solutes, including nitrate. Pollution fronts of these targeted chemical components are still limited to the first 15 m of the subsoil. At deeper level, about 20-25 m, the effects of agricultural pollution and acidification were indicated by chemical indicators that have not been considered by others: oxidation capacity, the sum of cations and chloride. Increasing trends of the conditionally conservative indicators 'oxidation capacity' and 'sum of cations' were found at a depth of 18-25 m below surface. Increasing trends for potassium were found at shallower depth (7-13 m), which is explained by retardation of potassium due to cation-exchange with calcium and magnesium. The modelled cation-exchange explained the shape of the concentration-depth profile and the increasing trends at shallow depth in the aquifer. © 2004 Elsevier B.V. All rights reserved

Regional modeling of cadmium leaching to groundwater in the Kempen region, The Netherlands

Sandy soils in the border area of Belgium and the Netherlands (the Kempen region), are heavily contaminated with cadmium and zinc by atmospheric deposition from nearby smelters. Leaching of heavy metals from the topsoil is a major risk for groundwater contamination. The sandy soils in the Kempen area are vulnerable for leaching due to the acidifying conditions in these soils. Regional modeling of groundwater contamination by leaching of cadmium from soils in a diffusely polluted area is the subject of this study. An attempt has been made to model the present and predict the future concentrations of cadmium in shallow groundwater and the metal binding processes in the unsaturated zone in the total Kempen area. Leaching of cadmium is spatially highly variable. It depends on the soil type, the groundwater depth and cadmium input concentrations. In the Kempen area, the heavy metal load to the soil is controlled mostly by atmospheric deposition and the net rainwater infiltration. The atmospheric deposition of cadmium decreases strongly with the distance from the zinc smelters. In the mid-seventies, a change in production processes caused a sharp decline of cadmium emission. There is no temporal or spatial data available about the (historic) atmospheric deposition of cadmium covering the total Kempen region. Therefore, the atmospheric deposition of cadmium was reconstructed from the analyzed cadmium content in forest soil samples. Forest soil samples were chosen because the cadmium contents in these soils are not influenced by the use of manure, (lime) fertilizers and sewage sludge. For 13 locations with varying distances from the smelters the historic atmospheric deposition of cadmium was calculated by iteration with the analyzed cadmium content in the soil. Cadmium adsorption coefficients (K_F) for the individual locations, which are needed for these calculations, were derived with existing meta-models as a function of soil properties like pH, organic matter and clay content. In this reconstruction, the historic changes in deposition rates of cadmium were linearly related to the zinc production of the smelters. The calculated depositions at the 13 locations were spatially interpolated to an area-covering map of atmospheric deposition rates with the distance from the smelters and the predominant wind direction as input variables. Leaching of cadmium from topsoil to groundwater is a function of soil type. Acid sandy soils of relatively low organic matter content demonstrate a low retardation capacity. The pH, organic matter, and clay content taken from the chemical characterization of soil types from the Dutch soil map were used to calculate Freundlich adsorption isotherms (K_F) for cadmium by using existing multiple linear regression models. Together with the groundwater level, this determines the breakthrough time of cadmium to the groundwater. Groundwater levels were derived from a regional groundwater model. The unsaturated zone model HYDRUS was used to model the breakthrough of cadmium for all unique combinations of soil type, groundwater level and cadmium input load. The individual maps were classified to get a unique combination of input parameters. The Van Genuchten parameters for modelling the unsaturated water flow were calculted with pedo-transfer functions soil parameters like texture, bulk-density and organic matter content. The results of the regional modeling shows that groundwater recharge exceeds the Dutch groundwater intervention limits in 43% of the modeled Kempen area in 2002. In 2050 this will be 64%

Nutriëntenhuishouding in de bodem en het oppervlaktewater van de Krimpenerwaard : bronnen, routes en sturingsmogelijkheden

In het project Monitoring Stroomgebieden zijn de afgelopen acht jaar vier stroomgebieden intensief bemeten en gemodelleerd met als hoofddoel de invloed van het mestbeleid op de oppervlaktewaterkwaliteit te kwantificeren en te onderzoeken hoe kan worden gestuurd op schoon water. Dit rapport beschrijft de eindresultaten van één van de onderzochte stroomgebieden, de veenweidepolder de Krimpenerwaard. De oppervlaktewaterkwaliteit in de Krimpenerwaard wordt bepaald door de afzonderlijke woorden in het woord 'veenweidepolder'; het 'veen' - de afbraak daarvan - en de 'weide' - de bemesting daarvan - zorgen samen voor ongeveer 80% van de totale nutriëntenbelasting van het oppervlaktewater en dragen hier ongeveer in gelijke mate aan bij, terwijl het 'polder'-aspect impliceert dat de inlaat van gebiedsvreemd water in de zomer de derde belangrijke nutriëntenbron is. Voor de oppervlaktewaterkwaliteit is in de Krimpenerwaard fosfor een probleem met zomerconcentraties die ver boven de KRWnorm liggen. In dit rapport wordt ondermeer uitgelegd hoe dit komt en wat hieraan kan worden gedaan