Natural radionuclides in mineral fertilizers and farmland

Abstract

Contemporary agriculture production is based on use of mineral fertilizers, which however can have high activity of natural radionuclides and so cause the appearance of technologically elevated radioactivity. In order to determine the influence of mineral fertilizers application in arable land, there was used gamma spectrometric method for defining the activity of natural radionuclides (40 K, 238U, 226Ra) in imported mineral fertilizers as well as in arable and fallow land in the area of suburban municipalities of Belgrade. The obtained results have shown that in the tested mineral fertilizers the measured activity of 40K ranged from 70 to 4590 Bq/kg, 238U from 18 to 1400 Bq/kg and 226Ra from 15 to 999Bq/kg. Average activities of natural radionuclides in arable land are: 626 Bq/kg for 40K, 54 Bq/kg for 238U, 55 Bq/kg for 226Ra and 55Bq/kg for 232Th, and in fallow land 596 Bq/kg for 40K, 54 Bq/kg for 238U, 54 Bq/kg for 226Ra and 53 Bq/kg for 232Th. Average values of radium radioactivity equivalent (175 Bq/kg) and index of radiation risk (0,48), point out that in the tested areas there is no significant radiation risk for inhabitants due to terrestrial exposure. This investigation has also shown that current use of mineral fertilizers has not caused the increase of natural radioactivity in the tested arable land.

Savremena poljoprivredna proizvodnja se bazira na upotrebi mineralnih đubriva, koja mogu imati visoke aktivnosti prirodnih radionuklida i usloviti pojavu tehnološki povišene radioaktivnosti. U cilju određivanja uticaja primene mineralnih đubriva na koncentraciju radionuklida u obradivom zemljištu, gamaspektrometrijskom metodom određivana je aktivnost prirodnih radionuklida (40K, 238U, 226Ra) u mineralnim đubrivima iz uvoza, obradivom i neobradivom zemljištu sa područja prigradskih opština grada Beograda. Dobijeni rezultati su pokazali da se u ispitivanim mineralnim đubrivima izmerena aktivnost 40K kretala od 70 do 4590 Bq/kg, 238U od 18 do 1400 Bq/kg i 226Ra od 15 do 999 Bq/kg. U obradivom zemljištu prosečne aktivnosti prirodnih radionuklida su 626 Bq/kg za 40K, 54 Bq/kg za 238U, 55 Bq/kg za 226Ra i 55 Bq/kg za 232Th, a u neobradivom zemljištu 596 Bq/kg za 40K, 54 Bq/kg za 238U, 54 Bq/kg za 226Ra i 53 Bq/kg za 232Th. Srednje vrednosti radijumskog ekvivalenta aktivnosti (175 Bq/kg) i indeksa radijacionog rizika (0,48) ukazuju na to da na ispitivanim lokacijama ne postoji značajni radijacioni rizik za stanovništvo usled terestrijalnog izlaganja. Ova istraživanja su pokazala i da dosadašnja upotreba mineralnih đubriva nije uzrokovala povišenje prirodne radioaktivnosti na ispitivanim oranicama.