NATURAL RADIOACTIVITY OF FERTILIZERS WIDELY USED IN THE AGRICULTURAL LANDS OF EGE REGION IN TURKEY

This is a preliminary study to determine the natural radionuclides of the commercial chemical fertilizers and rock phosphates which are widely used in the agricultural lands of Ege region in the west of Turkey. Mainly the fundamental raw materials of all phosphorous (P) containing fertilizers are examined. Gamma spectrometric measurements of 226Ra, 232Th and 40K activities were made on sixty-eight straight and compound commercial fertilizers, as well as on the nine phosphate rocks. The activity concentrations of 226Ra in the phosphate rocks were found to be in the range of 326 and 788 Bq kg-1 while those of 232Th and 40K were found to be much lower, ranging from 50 Bq kg-1 to levels so low that they were undetectable. Normal super phosphate (NSP) and triple super phosphate (TSP) exhibited relatively higher 226Ra activities than the rest of studied P based fertilizers. 40K activities in potassium sulfate and nitrate fertilizers w up to about 104 Bq kg-1. In particular, the activity concentrations of the 226Ra in NP and the majority of NPK fertilizers, which are the most widely used types in the cultivated soils of the Ege region, appeared much lower, and in some cases, were undetectable. These results are of great significance in terms of sustainable agriculture involving the use of phosphate-based fertilizers.