Dating of sedimentation rate and the radioactivite and metal pollution using pb-210 method in golden Horn, İstanbul

Haliç (The Golden Horn), which is located in a dense residential area of Istanbul, is an important aquatic ecosystem, that has been polluted in various ways for years. Domestic wastes, and chemical wastes from industrialization activities that have been increasing since the 1940s cause metal and radionuclide infiltration into and around the estuary. In order to determine the metal and radioactive pollution in Haliç, where has historical, cultural and commercial importance; sediment core samples taken from different parts of the Golden Horn were examined with different methods for various trace elements and radionuclides. Their approximately 100 years of change and deposition levels were determined. In this study, three sediment cores (S-1, S-2 and S-3) taken from four different stations. They were dated by using Cs-137 and Pb-210 dating methods, and the average annual sedimentation amount was determined. However, S-4 core could not be dated, since the distribution of Pb-210 in the S-4 core was not suitable for dating. Activity concentrations of Cs-137, Pb-210, K-40, Ra-226 and Ra-228 radionuclides and concentrations of Al, As, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sb, Sn, Ti, V and Zn in the cores were demonstrated until about 100 years ago. The annual sedimentation amount in the study area was found to be 0,92 cm, 0,95 cm and 0,97 cm for S-1, S-2 and S-3 stations, respectively. It was observed that the activity concentrations of natural radionuclides (K-40, Ra-226, Ra-228) were consistent with the values in the current literature. The activity values of these radionuclides show a decline with small variations in all core profiles from top layer to bottom layer. CF (Contamination factor), EF (Enrichment factor), PLI (Pollution load index) and Igeo (Geoaccumulation index) values were determined in the obtained metal concentrations. The changing values of these metals, which are enriched in the environment, were determined according to years and the effect of their anthropogenic source. The pollution indexes show that the concentrations of As, Cd, Cr, Cu, Pb, Sb, Sn were above the world average. Metal concentrations, which increased between 1930 and 1990, started to decrease in some metals (Al, Ba, Sn) with the beginning of rehabilitation processes in the 90s, but in many (As, Cd, Cu, Ni, Sb, Ti, Zn) of the metals has been continued to increase. With the thesis study presented here, metal and radioactivity pollution levels and their chronological changes were determined for last a 100-year period. This study revealed that pollution sources continue to exist, and current pollution continues. These results emphasize that it is important to follow the region in terms of marine pollution, and rehabilitation processes should be developed including anthropogenic resources that produce non-decreasing pollutants presented in current study.