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Project directory according to Nr.3.2 BNBest-BMBF98 <http://www.fz-juelich.de/ptj/datapool/page/490/Schlussbericht.rtf> 1. Problem / tasks / goalProblemAbout sixty years after the end of World War II, large areas in Germany are still polluted to a middle or low degree with the explosive 2,4,6-trinitrotoluene (TNT) and its co-contaminants like aminodinitrotoluenes (ADNT), trinitrobenzene (TNB) or dinitrotoluenes (DNT). Soil contamination is resulting from German explosive war production and filling facilities. Furthermore smaller non-detected hot spot areas should be expected. Physical-technical soil sanitation methods must be carried out ex situ. Therefore they are expensive and only punctually used for the decontamination of highly polluted places. Microbiological off-site remediation methods also have the expensive problem of soil excavation and the necessity of addition of organic co-substrates. On the search for payable and socially accepted soil decontamination possibilities the development of soil protecting, biological soil sanitation techniques thus progresses also for economic reasons. For those large low or middle contaminated areas offers itself the search for economical, plant-based restoration methods known as phytoremediation. Modern aspects of phytoremediation of organic pollutants are summarized by Trapp (2000) [#Lit 11], where the role of trees is emphasized. The author criticizes that phytotoxicity and pollutant balance in field trials is documented only in few cases. The number of papers dealing with phytoremediation problems is nearly exploded during the last decade, especially if one tries to use an internet search engine, e.g. google.com. So it became necessary to separate those comparatively few investigations regarding the sanitation potential of trees by means of the term "dendroremediation" (dendros = tree) from the bulk of information referring to herbaceous plants. The term dendroremediation was introduced for the use of trees to clean-up soils contaminated with inorganics by the Michigan State University. Despite various similarities in the physiological responses of trees substantially differ from herbs, particularly in their longevity and in their long-lasting influences on soil and water regimes. TasksIn Germany, a large number of the explosive-contaminated areas is already covered with forest ecosystems, where preferentially coniferous trees or mixed woodlands occur. Therefore, parallel investigation of the remediation suitability of specially selected tree clones of willow and poplar (see Schoenmuth 1996 [# Lit 5], Schoenmuth et al. 1997a [#Lit 7], Schoenmuth et al. 1997b [#Lit 8]) is nececessary in respect to the dendroremediation potential of those trees, which already grew for decades on the polluted areas. The project description (project request in 1997 [#Lit 6] therefore was focused on the following subtasks: 1. a) Testing the decontamination potential of TNT-tolerant willow and poplar clones, selected in a forerunner project under outdoor conditions. 1.. b) Testing TNT-sanitation potential of trees, which are typical for German old weapon sites (e.g. Norway spruce, birch, Scots pine). 2. Radiotracer measurements using [14C]-TNT for the mass balance during TNT plant uptake in greenhouse pot experiments. 3. Analytics of typical old weapon site trees, growing on TNT-polluted areas. GoalThe main aims of the project were fixed as follows: § Gain sanitations proposals for TNT-contaminated soils by means of genetically defined trees for practical purposes. § Locate and quantify extend and kind of metabolisation of nitroaromatics within the tree and in the surrounding soil. § Find prognosis aids for the assessment of the potential influence of old weapon site trees on the further development of soil contamination (time course of „natural attenuation“).
last update: 18.02.04 19:40 by BerndSchoenmuth@yahoo.de |
