Projekt

Vietnam is characterized by a coastal line of a length of 3.200 km extending from Mongai (Vietnamese-Chinese border) to Hatien (Vietnamese-Cambodian border). Along this coastline 16 rivers reach the Eastern Sea creating large deltas and tidal flats covered at their landward margins by mangrove vegetation. Thus, the sedimentary deposits laid down in these deltas and tidal flats are both of marine and fluvial origin containing different proportions of decomposed organic matter originating from terrestrial, mangrove swamp and marine sources. It is well known that these tropical and subtropical coastal regions are sustaining large numbers of biological communities. They are of paramount importance as spawning regions for fish, prawns and shellfish. Prof. Dsc. Pham Van An, University of Mining and Geology, Hanoi, and his students have started to work on the sedimentology of the tidal flat area between the cities of Haiphong and Quangninh, Nordeastvietnam. The coastal line is about 200 km long including the famous Halong Bay and part of the delta of the Red River. First results point to highly variable grain size distributions and substantial ranges of the contents of light and heavy minerals, microorganisms and organic carbon.The main objective of this study shall be the quantitative elaboration of the major processes controlling the flux of both inorganic and organic compounds in the tidal flat area described above. Since this region is heavily used by man, e. g. through urbanization, rapid industrialization and extensive agricultural activities in the hinterland, industrial and domestic wastes are discharged into the sea along a substantial percentage of the coastline. It is expected, that the dispersion patterns of anthropogenic pollutants will be extremely variable due to differences in hydrology, sediment texture, mineralogical composition, and contents of organic carbon. Thus, in order to evaluate the major processes governing the dispersion and fate of pollutants in the tidal flat region, the following working steps have to be undertaken:
a) One goal of this work has to be the elaboration of maps depicting the distribution of grain sizes, light and heavy minerals, microorganisms and contents of organic carbon.

b) In grain size fractions < 63 µm the contents of major and trace elements have to be determined by X-ray fluorescence spectrometry. Elements of possible high anthropogenic inputs, e.g. heavy metals, have to be included. Maps of the distribution of these latter elements are crucial for, e.g., pinpointing industrial and/or domestic sources of pollutants.
c) In sediment samples of those sections of the tidal flat polluted by heavy metals the distribution of anthropogenic organics has to determined. The contents of halogenated carbohydrates used extensively in industrial processes, pesticides widely used in agriculture, e.g., gamma-HCH, and organotin compounds used, i. a., as antifouling agents in paints for ship hulls, have to be determined in the laboratories of the Chair of Applied Geology of FAU.