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(75-09) Modelling DDT release from contaminated soils in Italy. Di Guardo, Antonio*,1, Calamari, Davide1, 1 Environmental Research Group, DBSF, University of Insubria, Varese, Italy ABSTRACT- The recent DDT contamination of Lake Maggiore (Italy) offers an important experimental opportunity for studying the release of DDT from soils. The high DDT concentrations, discovered in 1996 in many fish species, caused the ban of fish consumption. DDT was produced by a chemical company located in a subalpine valley (Ossola valley), in which flows Toce River, tributary of Lake Maggiore. In the area surrounding the chemical plant high DDT concentrations in soil and vegetation were found. The quantification of the release from contaminated soil and the following migration towards the atmosphere and surface water plays an important role in understanding future DDT trends in the different lake compartments and especially biota. In order to study this phenomenon, many environmental phases from Ossola Valley, such as soil, vegetation, surface waters, suspended solids, sediment were monitored. The concentration values obtained allowed to reconstruct a contamination gradient in the valley and were used to setup and calibrate a basin scale multimedia fugacity model. This model integrates in a GIS (Geographic Information Systems) approach different soil submodels to predict the fate of DDT and its transport towards other environmental phases such as air and water. This approach can be useful in understanding how the different environmental conditions play a role in the pathway of DDT from the contaminated soil to the adjacent areas, in which very different environmental systems are present. These areas comprise several landscapes with a variety of media composition (forests, agricultural areas, glaciers, lakes etc) in which the subsequent DDT fate might be different. Key words: DDT, models, soil release, GIS |
