MATERIAL COMPOSITION OF BOTTOM SEDIMENTS UPSLOPE OF A SMALL RIVER

To date, the acute problem is the sharp deterioration of the ecological state of small rivers inUkraine. Therefore, a number of measures are being taken to improve them, including clearing river channels to restore the natural flow. After dredging works, bottom sediments are formed which are alluvium in the form of sand of various composition and organic matter - silt. These deposits can accumulate a variety of pollutants, including heavy metals. However, despite the possible ecological danger, they are stored in the dumps along the coast. In these dumps there are processes of dehumidification of sludge through filtration, changing chemical composition, the possible migration of chemical elements into the soil. Such bottom sediments can act as a secondary source of environmental pollution. In the article the material composition of bottom sediments and their dumps is considered on the example of the river Mokra Sura. For the study, samples from ten control points were selected. Selected samples are moist soil from dark gray to black. To assess their material composition, studies have been conducted to determine the content of organic matter in the analyzed soils and bottom sediment, the mineral composition of the ozonated samples and their chemical composition. Studies show that the bottom sediments of theSukraRivercontain a high amount of organic matter, which could be favorable for improving the soil quality, but they are contaminated with toxic substances, mainly in a soluble form, which may lead to deterioration of the natural properties of soils. The obtained results indicate that the material of dumps can be a source of secondary contamination of the river and surrounding soils, so it can not be left on the shore. It also can not be used as fertilizer or substrate for agricultural purposes. It must be utilized in other ways. The given data show that it is necessary to conduct detailed research of bottom sediments formed during dredging works and only then decide on their further use. It is also advisable to group the small rivers in the composition of the bottom sediments with the degree of their environmental hazard.