engleski

Radium and uranium in phosphate fertilizers and their impact on the radioactivity of waters

The study of radioactivity in the phosphate fertilizers and waters of Kanovci area was performed in order to determine the onfluence of the aplication of phosphate fertilizers on the radioactivity of water. The aczivity of 226-Ra, 228-Ra, 235-U and 238-U was measured in different types of phosphate fertilizers and waters by means of gamma-ray spectrometry. Surface water, water from drainage channels, shallow groundwatwr and deep groundwater samples were collected from Kanovci agricultural and well field area in Eastern Slavonia, where phosphate fertilizers have been used for the past 15 years. 137-Cs was also measured in water samples. The typical phosphate fertilizer used in the Kanovci area contains 75 Bq/kg of 226-Ra, 9 Bq/kg of 228-Ra, 52 Bq/kg of 235-U and 1120 Bq/kg of 238-U. The estimated annual deposition of uranium and radium in soils of the agricultural and well field area in Kanovci is: 4.5 Bq/m2 for 226-Ra, 0.5 Bq/m2 for 228-Ra, 3.1 Bq/m2 for 235-U and 67 Bq/m2 for 238-U. The greatest concentrations of both uranium isotopes are measured in water from drainage channels with mean value of 120 Bq/m3 for 238-U and 5.5 Bq/m3 for 235-U. The concentration of both radium isotopes generally increase with depth of water as distinct from uranium, whose concentrations in deep groundwater are much lower. The highest concentrations of 137-Cs were measured in water from drainage channels ; it was not detected in deep groundwater. The 238-U/226-Ra activity ratio (AR) is the highest in water from drainage channels and the Bosut River, whilw in deep groundwater the ratio is only 1.6. Results indicate that high uranium concentrations in surface water, shallow groundwater and water from drainage chanels are caused by phosphate fertilizer application in agriculture on the Kanovci area.

uranium ; radium ; phosphate fertilizer ; radioactivity impact ; water

nije evidentirano