Determination of ecological half-life of 137Cs in Eastern Black Sea region and various models on 137Cs

As a result of the Chernobyl accident happened in 26th April 1986, all the radionuclides in the reactor core (50 million Curie) contaminated the atmosphere. Radioactive gas and materials reached the altitude of 1200 meters. The radioactive cloud from the Chernobyl reactor reached the northern and central Scandinavian countries on 28th April 1986 due to the wind from south. As a result of the atmospheric changes, this radioactive cloud contaminated many European countries and on 30th April/5th May finally contaminated our country. The radioactive cloud changed the direction and passing the Black Sea, it also contaminated the Eastern Black Sea Region of Turkey due to the heavy rain on those days. Is has been shown that 137Cs is still eminent in that region because of its relatively long half-life (~ 30 years).In this theses, 1) activity concentrations of 137Cs in mosses and lichen samples collected from different sampling points have been determined; 2) Ecological half-life of 137Cs in mosses and lichen species have been determined; 3) Vertical migration of 137Cs through soil matrix has been modeled and as a results, diffusion coefficients have been determined; 4) As drying of soil samples takes a lot of time before measurements, in an emergency case like nuclear power plant accident, a solution has been proposed to skip the drying process for soil samples and 5) Dose rate due to 137Cs in soil has been calculated.