Magnetic tracing of soil pollutants

The magnetic susceptibility of soils is a parameter which experiences growing interest in recent years. Its most important application is the exact delineation of polluted areas. This application is based on the fact that magnetic particles and heavy metals are both produced during combustion processes and therefore appear together in the environment. Partly these metals are adsorbed on the surface of the magnetic particles, partly they are incorporated. The general suitability of the magnetic mapping method for pollution analysis could be proven but we still lack information about the behaviour of the magnetic minerals during the transport processes in the air and after their deposition. The proposed project aims at closing this gap in our knowledge. The project is composed of two intertwining components. On the one hand we will compare the results of magnetic mapping with the results of regional climate analyses to gain a better understanding of the transport via the air. On the other hand we will combine mineral magnetic measurements in vertical soil profiles with mineralogical analyses to understand the behaviour of the magnetic minerals in the soils. These minerals may be converted into non-ferrimagnetic iron minerals and vice versa. Therefore we aim at a comprehensive analysis of the iron mineralogy in polluted and non-polluted soil profiles. Two areas will be investigated by the combination of magnetic mapping and climate analysis. First the area Veitsch where a pollution source is located in a narrow Alpine valley. There, the method can be tested and refined. Then, the city of Graz will be investigated where a mixture of sources has to be taken into account. Soil profiles will be sampled in the area Liezen, an Alpine region without major pollution sources where we expect to find mostly unpolluted profiles. Then, further profiles will be chosen within the Veitsch area after the regional analysis. The magnetic and mineralogical analyses will enhance our understanding of transport and transformation processes of magnetic minerals in soils which are important for several areas of research. We will gain information on the weathering processes of natural iron minerals as well as on the neoformation of iron minerals during pedogenesis. These informations are important for soil science because iron minerals are indicators of the conditions during pedogenesis. Furthermore we will define the extent to which anthropogenic dust affects the different soil horizons. Together with the regional analyses these informations can be used to consider the distribution of potentially hazardous dusts in regional and urban planning.