4 research outputs found
Aktivnosti radiocezija u pŔenici u Hrvatskoj
Results of systematic, long-term measurements of 137Cs activities in wheat are summarized. 137Cs fallout activity affected wheat activity the coefficient of correlation being 0.91. A model used by UNSCEAR was used to describe l37Cs transfer from fallout deposition to wheat. The transfer coefficient was calculated to be 6.1 x 10-3 Bq yr kg-1/(Bq m-2). The dose incuned by wheat consumption was estimated for the Croatian population, the annual collective equivalent dose being approximately 550 man Sv for the 1965-1992 period. After the Chernobyl nuclear accident the 134Cs: 137Cs activity ratio in wheat was - 0.5, and did not differ from that for other environmental samples.Prikazani su rezultati dugogodiÅ”njih sustavnih mjerenja aktivnosti 137Cs u pÅ”enici. Aktvnost 137Cs u radioaktivnim oborinama utjeÄe na aktivnost pÅ”enice, uz koeficijent korelacije 0,91. Transfer 137Cs od radioaktivnih oborina do pÅ”enice najbolje opisuje model UNSCEAR-a. Transferni koeficijent procijenjen je na 6.1 x 10-3 Bq god kg-1/(Bq m-2). Kolektivna ekvivalentna doza uslijed konzumacije pÅ”enice za hrvatsku populaciju procijenjena je na oko 550 Äovjek Sv za period od 1965. do 1992. godine. Poslije nuklearne nesreÄe u Äernobilju omjer aktivnosti 134Cs:137Cs u pÅ”enici bio je - 0,5 i nije se razlikovao od vrijednosti omjera u ostalim uzorcima iz okoliÅ”a
The monitoring of fallout in Zagreb
Radioaktivno zagaÄenje prati se veÄ 12 godina u okviru kontrole zagaÄenja okoliÅ”a na podruÄju Zagreba. Kontrola obuhvaÄa mjerenja beta i gama-aktivnosti. U radu su opisane primijenjene metode i dani rezultati.For the last 12 years the radioactive contamination of the rain has been monitored within a larger environmental survey. Beta and gamma activity control has been included. Data are presented on variations in radioactivity due to the time elapsed since the last nuclear explosion
Radioactivity in Biosphere and Occupational Exposure in Croatia
U radu su prikazani rezultati sustavnog istraživanja radioaktivnosti životne i radne sredine u Republici Hrvatskoj od poÄetka Å”ezdesetih godina. Istraživana je radioaktivnost zraka, oborina, tla, rijeka, mora i jezera, pitke vode te ljudske i stoÄne hrane, kao i vanjska izloženost za radnike profesionalno izložene ionizirajuÄem zraÄenju. Maksimalna radioaktivna kontaminacija fisijskim radionuklidima zabilježena je ranih Å”ezdesetih godina, u vrijeme najintenzivnijih atmosferskih nuklearnih pokusa. Od tada radioaktivnost radioaktivnih oborina eksponencijalno opada. Nuklearna nesreÄa u Äornobilju dovela je u Republici Hrvatskoj do ponovnog poveÄanja radioaktivnosti 137Cs u okoliÅ”u, dok je poveÄanje radioaktivnosti 90Sr, zbog njegove manje hlapljivosti, bilo neznatno. No, nakon tog kratkotrajnog poveÄanja ponovno je doÅ”lo do eksponencijalnog pada radioaktivnosti, tako da je godine 1998. prosjeÄna brzina apsorbirane doze u zraku iznosila 0,128Ā±0,004 Ī¼Gy/h. ProsjeÄan pripadnik hrvatske populacije je stoga zbog izloženosti osnovnom zraÄenju na godiÅ”njoj razini primio dozu od oko 1,12Ā±0,04 mSv. Ukupna kolektivna doza ukljuÄuje i dozu uzrokovanu primjenom izvora ionizirajuÄih zraÄenja u medicini te je znaÄajan naglasak stavljen na kontrolu kakvoÄe izvora zraÄenja (koja se sustavno provodi od 1985) kako bi se smanjila ukupna kolektivna doza koju primi hrvatsko puÄanstvo.This paper presents results of long-term investigations of radioactivity in general and occupational environments in the Republic of Croatia. Investigations of environmental radioactivity and occupational exposure monitoring in Croatia have been systematic since the early sixties. Investigations included radioactivity of the air, fallout, soil, river, sea and lake water, tap water, human foodstuffs, and animal feed. External dosimetry monitoring is carried out for workers occupationally exposed to ionising radiation in medicine, and industry. Radioactive contamination with fission radionuclides is associated with deposition of fallout originating from atmospheric explosions of nuclear weapons as well as from regular operation of nuclear facilities. Among hundreds of different radionuclides contained in various types of fallout only a few significantly contribute to the dose, particularly 90Sr and 137Cs. The maximum radioactive contamination with fission radionuclides was recorded in the early sixties, at the time of most intensive atmospheric nuclear tests. The fallout radioactivity has been exponentially decreasing ever since. The nuclear accident at Chornobyl temporarily raised 137Cs radioactivity levels in Croatia, whereas the increase in 90Sr radioactivity was not significant due to its low volatility. After a short-term increase, radioactivity dropped back to the pre-Chornobyl levels. Apart from radioactivity of fission products, investigations involved natural radioactivity and technologically enhanced natural radioactivity. Particular attention has been paid to radon as the most relevant source of natural radiation for humans. In 1998, the average absorbed dose in the air was 0.128Ā±0.004 Ī¼Gy/h. Consequently, an average Croat received the annual dose of 1.12Ā±0.04 mSv through exposure to background radiation. However, as the overall collective dose includes the dose received by medical and civil use of radiation sources, significant effort has been put on the quality control of radiation sources (systematically implemented since 1985) as an important step for reducing the overall collective dose of Croatian population