Prisustvo i rizici ²²⁶Ra u prirodnim vodama

master's thesis

• Title (english): Concentrations and risk assessment of ²²⁶Ra in natural waters
• Author: Jasna Žibert
• Mentor: Ivana Kmetič (mentor)
• Committee member: Teuta Murati (član povjerenstva)
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; (Department of Chemistry and Biochemistry); (Laboratory for Toxicology); Zagreb
• Defense date and country: 2020-07-21, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology

Abstract

Jedan od izvora prirodne radioaktivnosti kojoj je čovjek izložen je prirodna voda. ²²⁶Ra je prirodan radionuklid, alfa emiter čija se razina u vodi kontinuirano prati zbog toksikološkog djelovanja alfa čestica koje nastaju raspadom ²²⁶Ra na organizam. Nakon oralnog unosa ²²⁶Ra putem pitke vode toksikokinetika je slična putu kalcija u organizmu i taloži se u kostima. U kostima raspadom ²²⁶Ra emitiraju se alfa čestice koje imaju negativan učinak na okolne stanice te moguća krajnja posljedica izloženosti ovakvom tipu zračenja je razvoj karcinoma kosti, posebno osteogenog sarkoma. U ovom radu, koncentracija aktivnosti ²²⁶Ra određena je u uzorcima vodovodne vode, vode iz cisterna, rijeka, te voda iz mineralnih i termalnih izvora. Korištena je radiokemijska separacija ²²⁶Ra, taloženjem s BaSO₄ dok je aktivnost mjerena alfa brojačem. Dobivene koncentracije aktivnosti ²²⁶Ra u različitim uzorcima prirodnih voda kretale su se od 3 Bq mˉ³ u cisternoj vodi do 8990 Bq mˉ³ u termalnoj vodi. Uzimajući u obzir učestalost konzumacije različitih tipova prirodnih voda izračunate su ukupne efektivne doze za sve uzorke koje su u skladu s nacionalnim propisima (0,1 mSv yˉ¹.). Za uzorke vodovodne vode, vode iz cisterna, rijeka i mineralnih voda ukupna efektivna doza kretala se od 0,32 do 90,94 μSv yˉ¹, odnosno za termalne vode od 0,81 do 70,48 μSv unutar 4 tjedna.

Abstract (english)

One of the sources of exposure to natural radioactivity for humans is natural water. ²²⁶Ra is a natural radionuclide, an alpha emitter which level is continuously monitored in water because of toxicological effect of alpha rays on organism which is a by-product of ²²⁶Ra decay. Following oral administration via drinking water, the toxicokinetics of ²²⁶Ra is similar to the calcium pathway in the body and it could be deposited into the bone. Being an α particles-emitting radionuclide, the 226Ra irradiates bone surface-lining cells and has resulted in an excess incidence of carcinoma, in particular osteogenic sarcomas. Activity concentration of ²²⁶Ra is determined in samples of tap water, water from cisterns, rivers, mineral and thermal water. ²²⁶Ra is radio-chemically separated from water by precipitation using BaSO₄ and the activity is measured by alpha counting. Activity concentrations of ²²⁶Ra in different samples ranged from 3 Bq mˉ³ in water from cistern to 8990 Bq mˉ³ in thermal water. For different types of natural water, taking into account the different uptakes, total effective doses were assessed and the results were in compliance with national regulations (0.1 mSv yˉ¹). For samples of tap water, water from cisterns, rivers and mineral waters effective dose was in the range 0.32 - 90.94 μSv yˉ¹, whereas for thermal waters it ranged from 0.81 - 70.48 μSv for a period of 4 weeks.

• Keywords: ²²⁶Ra; alfa zračenje; voda; radioaktivnost; doza
• Keywords (english): ²²⁶Ra; alpha radiation; water; radioactivity; dose
• Language: croatian
• URN:NBN: urn:nbn:hr:159:284171
• Study programme: Title: Food Safety Management; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka upravljanja sigurnošću hrane (magistar/magistra inženjer/inženjerka upravljanja sigurnošću hrane)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-07-21 11:35:26