Radionuklidi i teški metali u zemljištu u okolini termoelektrane "Nikola Tesla" u Obrenovcu

Abstract

Koncentracije aktivnosti radionuklida (238U, 226Ra, 232Th, 40K, 137Cs) i koncentracije teških metala (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, Zn) su određene u zemljištu na 95 lokacija u okolini najveće termoelektrane u Srbiji. Njihova prostorna distribucija na istraživanom prostru analizirana je ordinarnom kriging metodom. Stepen zagađenje zemljišta procenjen je na osnovu faktora obogaćenja (EF), geo-akumulacionog indeksa (Igeo), faktora kontamonacije (CF), indeksa zagađenja (PLI) i K-parametra. Na osnovu vrednosti EF-a zaključeno je da je na istraživanom prostoru postoji izostanak i/ili slabo obogaćenje zemljišta metalima. Korelacije radionuklida, teških metala i fizičkohemijskih karakteristika zemljišta ispitane su hijerarhijskom analizom grupisanja. Mape prostorne distribucije analiziranih zagađujućih supstancija ukazuju da su njihove najviše koncentracije na istraživanom prostoru u pravcu dominantnog vetra. Na osnovu dobijenih rezultata zaključeno je da rad termoelektrane nema značajan negativni uticaj na njeno okruženje u pogledu sardžaja radionuklida i teških metala. Na istraživanom prostoru srednja vrednost procenjene jačine doze zračenja na stanovništvo iznosi 75,3 nGy h–1, a godišnja efektivna doza varira u opsegu 51,4 do 116,4 μSv. Jačina doze zračenja za biotu izračunate primenom softverskih modela ERICA Tool i RESRAD BIOTA na istraživanom prostoru variraju u opsegu 0,38 – 14,35 μGy h–1. Radijacioni rizik na biotu procenjen primenom ovih softvera, ukazuje da se na istraživanom prostoru usled niskih doza jonizujućeg zračenja neće ispoljiti deterministički efekti na nivou populacije.

Activity concentrations of radionuclides (238U, 226Ra, 232Th, 40K, 137Cs) and concentrations of heavy metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, V, Zn) were analysed in soil samples from 95 locations in the vicinity of the largest coal fired power plant in Serbia. Their spatial distribution in the investigated area was analysed using ordinary kriging. The soil pollution status was assessed using enrichment factor (EF), geo-accumulation index (Igeo), contamination factor (CF) and pollution load index (PLI) and K- parameter. Based on values of EFs it was concluded that in the investigated area there is deficient to minimal enrichment of metals of soils. Correlations between radionuclides, heavy metals and soil properties were determined by hierarchical cluster analysis. The distribution maps of analyzed substances indicate that the highest concentrations corresponding with the predominant wind directions. From the results obtained it can be concluded that operation of the coal fired power plant has no significant negative impact on the surrounding environment with regard to the content of investigated radionuclides and heavy metals. In the investigated area the mean total absorbed dose rate to population was 76.3 nGy h–1, and the annual effective dose ranged from 51.4 to 114.2 μSv. In the investigated area dose rate to biota derived using software ERICA Tool and RESRAD BIOTA ranged from 0,38 – 14,35 μGy h–1. Using these software estimated radiation risk to biota in the study area due to low doses of ionizing radiation will not exhibit deterministic effects at the population level.