Magnetic Study of Sediments from the Vistula River in Warsaw—Preliminary Results

The aim of the study was to identify magnetic particles in the sediments of Warsaw part of the Vistula river (Poland) and the impact of anthropogenic factors on the magnetic susceptibility. One of the most important parts of this study was to determine the procedure for sediment sampling and preparation of material for magnetic measurements. The paper presents results of the preliminary study on the test collection of sediment samples from the Vistula river bank within Warsaw. The main magnetic study was carried out on the collection of sediments taken from six areas with different impact of anthropogenic sources of pollution using the procedure developed for test collection. For samples of sediments, several magnetic parameters, such as magnetic susceptibility χ, temperature dependent magnetic susceptibility, and hysteresis loop parameters, were determined. The study showed that the magnetic susceptibility of sediments reflects the anthropogenic impact. In the city center, the magnetic susceptibility reached maximum values which reflect the highest anthropogenic factor. The lowest magnetic susceptibility values were recorded in sediments taken from out of the city center areas which shows relatively low impact of anthropogenic factor. The fine-grained fractions of sediments contain most of the magnetic particles in which multidomain magnetite is the main magnetic phase. It was found that the spherical-shaped particles represent a significant part of magnetic fraction of sediment. The results bring us to the conclusion that the application of magnetic methods for study of river sediments is very important for understanding and tracing the anthropogenic input in the river sediments.