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Praćenje i određivanje radioaktivnih tvari u zraku provodi se u cilju detekcije neželjenih akcidenata kao i za procjenu efektivnih doza koje primi stanovništvo. Jedna od metoda kojom se određuje količina radioaktivnih tvari u zraku je mjerenje ukupne beta aktivnosti zraka. Lebdeće čestice aerodinamičnog promjera manjeg od 10 μm su inhalabilne, ulaze u dišne puteve i mogu štetno djelovati na ljudsko zdravlje. U sklopu državne mreže za trajno praćenje kvalitete zraka u Republici Hrvatskoj se na više lokacija prate razine lebdećih čestica, a u Institutu za medicinska istraživanja i medicinu rada je smješten referentni laboratorij za određivanje sastava čestica. U ovom su radu prikazani rezultati određivanja PM10 frakcije lebdećih čestica, razine olova i talija te ukupne beta aktivnosti u toj frakciji, na mjernoj postaji državne mreže u gradu Zagrebu (postaja Zagreb-1) tijekom 2021. godine. 24-satni uzorci sakupljeni su prosisavanjem 720 m3 zraka na filtre od kvarcnih vlakana (Whatman, QMA). Masena koncentracija PM10 čestica određena je gravimetrijski. Iz alikvota filtra, nakon mikrovalne razgradnje uz dušičnu kiselinu, određene su razine olova i talija metodom masene spektrometrije uz induktivno spregnutu plazmu. Ukupna beta aktivnost mjerena je iz drugog alikvota filtra, najmanje 120 sati nakon uzorkovanja, u beta brojaču niskih aktivnosti Low-level beta Geiger-Müller multicounter system ; model RISØ GM-25-5. Rezultati pokazuju da je srednja godišnja masena koncentracija PM10 čestica iznosila 24, 1 μg/m3, a kretala se u rasponu od 2, 4 μg/m3 do 140, 6 μg/m3. Srednja godišnja masena koncentracija olova u PM10 česticama iznosila je 1, 59 ng/m3, a talija 0, 004 ng/m3. Najviše dnevne vrijednosti masenih koncentracija olova i talija izmjerene su u veljači i iznosile su 10, 31 ng/m3 za olovo i 0, 016 ng/m3 za talij. Značajno više vrijednosti PM10 čestica zabilježene su tijekom sezone grijanja, od siječnja do ožujka i od listopada do prosinca. Nije nađena sezonska ovisnost razina olova i talija, kao niti ukupne beta aktivnosti u PM10 česticama. Prosječna vrijednost ukupne beta aktivnosti zraka u promatranom razdoblju iznosila je 1, 41 mBq/m3, s dnevnim vrijednostima od 0, 24 mBq/m3 do 5, 17 mBq/m3. Uočeno je da su se pojedine više vrijednosti ukupne beta aktivnosti podudarale s povišenim vrijednostima PM10 čestica, olova i talija.

Kalij se u okoliš može taložiti iz više izvora - morske soli, prašine iz tla, biogenih emisija i izgaranja biomase. Glavni cilj rada je bio odrediti i usporediti razine kalija i njegovog prirodnog radionuklida 40K u različitim vrstama atmosferskog taloženja (ukupna taložna tvar, suho taloženje i oborine), te procijeniti njegov glavni izvor. Uzorci su sakupljani na dvije lokacije u gradu Zagrebu tijekom 2022. godine. U prvoj polovici 2022. godine uzorci su sakupljeni u zapadnom industrijskom dijelu grada opterećeno prometom, dok su se u drugoj polovici godine sakupljali u sjevernom stambenom dijelu grada. Uzorci suhe depozicije kao i oborina sakupljani su kao tromjesečni uzorci, dok su uzorci ukupne taložne tvari sakupljani na mjesečnoj bazi, ali su ovdje prikazani kao tromjesečni prosjeci radi lakše usporedivosti rezultata s prethodno navedenim metodama. Prirodni radionuklid kalija, 40K, kao i ukupan K određen je visokorezolucijskom gamaspektrometrijom s germanijskim detektorom visoke čistoće (HPGe) u suhoj depoziciji i u oborini, dok je vodotopivi kalij u ukupnoj taložnoj tvari određen ionskom kromatografijom s konduktometrijskim detektorom. U istim uzorcima ukupne taložne tvari određivao se i vodotopivi organski ugljik (WSOC) metodom termičkooptičke transmisije s plamenoionizacijskim detektrom, a u svrhu izračuna omjera K+ i WSOC, koji može biti pokazatelj određenih izvora onečišćenja. Vidljivo je da su koncentracije kalija u ukupnoj taložnoj tvari kao i u oborinama više na sjeveru grada, dok su kod suhog taloženja više u zapadnom djelu grada Zagreba. Iz omjera K+ iWSOC vidljivo je da kalij u ukupnom taloženju u gradu Zagrebu dolazi kao produkt sagorijevanja biomase.

Coal fly ash and slag waste residuals from coal combustion are an issue of importance as one of the possible sources of environmental contamination and exposure to NORM. This study compares the results of different radiological risk assessment scenarios targeting terrestrial biota at a legacy site in Croatia that contains large quantities of coal ash with an enhanced content of radionuclides originating from previous industrial activities. The ERICA assessment tool was used for a risk assessment, which included data from borehole samples with a maximum depth of 6 m and trees as the primary reference organisms. The results of the risk assessments from various depth ranges found the radiological risk to the reference organisms to be negligible, regardless of the depth range, since the screening dose rate of 10 µGyh−1 was not exceeded in any of the assessments. The risk assessment results from all depth ranges show higher total dose rate predictions when the tool’s default CR values are used, compared to the site-specific ones, which is in agreement with previous studies on the application of the ERICA tool. A comparison of results from different spatial radiological risk assessments showed that sample depth does not affect the estimated total dose rate to biota.

Donos pijeska i prašine iz pustinja prirodna je pojava koja može štetno djelovati na ljudsko zdravlje i okoliš. Pustinjski pijesak sastoji se od čestica minerala koji potječu iz sušnih područja te može putovati na velike udaljenosti i pritom akumulirati razne onečišćujuće tvari antropogenog porijekla. Područje južne i jugoistočne Europe naročito je pogođeno takvim događajima, zbog donosa pijeska i prašine iz Afrike i Azije. Između 26. i 30. ožujka 2020. godine na području Hrvatske zabilježena je vrlo intenzivna epizoda donosa pustinjskog pijeska iz pustinje Karakum u središnjoj Aziji, koja je uslijedila neposredno nakon donosa iz Sahare. U ovom istraživanju promatran je utjecaj ovog događaja na brzinu ambijentalnog doznog ekvivalenta, ukupnu beta aktivnost i razine pojedinih onečišćujućih tvari u zraku. Brzina ambijentalnog doznog ekvivalenta pratila se u Zagrebu, Zadru i Slavonskom Brodu. Ukupna beta aktivnost zraka mjerena je u Zadru i na dvije lokacije u Zagrebu. Izmjerene su uobičajene vrijednosti za svaku lokaciju. Na mjernim postajama za trajno praćenje kvalitete zraka na kojima mjerenja provodi Institut za medicinska istraživanja i medicinu rada (u Zagrebu, Sisku i Slavonskom Brodu) u navedenom razdoblju zabilježene su izrazito povišene koncentracije frakcije lebdećih čestica PM10 (čestice ekvivalentnog aerodinamičkog promjera < 10 μm), koje ujedno predstavljaju i godišnji maksimum na tim lokacijama. Najviši 24-satni prosjeci masenih koncentracija PM10 kretali su se između 134 i 219 μg/m3 u Zagrebu te do 235 μg/m3 u Sisku i Slavonskom Brodu. Koncentracije frakcije lebdećih čestica PM2, 5 (čestice ekvivalentnog aerodinamičkog promjera < 2, 5 μm) nisu bile značajno povišene, što ukazuje na veliku zastupljenost grubih čestica (promjera između 2, 5 i 10 μm). U frakciji lebdećih čestica PM10 zabilježene su u tom razdoblju i povišene razine arsena, mangana i željeza. Ovi rezultati pokazuju da povremene epizode donosa pustinjskog pijeska mogu bitno utjecati na razine pojedinih onečišćujućih tvari u zraku. U ovom istraživanju nije pronađen značajniji utjecaj na brzinu ambijentalnog doznog ekvivalenta i ukupnu beta aktivnost zraka.

In situ gamma spectrometry allows complete characterization of gamma radiation fields at a given location through accurate and sensitive determination of the concentration of radionuclide activity in the soil. When compared with methods that include sample collection and subsequent laboratory analysis, the in situ method enables better soil representativeness, direct and accurate determination of areas of interest (hotspots), higher speed of measurements and reduced monitoring costs. All this makes it a very important complementary or alternative method to laboratory measurements, and unavoidable in case of accidents. The primary goal of this work is to present concepts behind a development and implementation of hybrid gamma spectrometry method for radiological monitoring of the environment of nuclear power plants. The hybrid method would integrate an innovative approach in determining areas of interest with the newly developed method for in situ gamma spectrometric measurements. This would increase the speed of radiological survey, which is critical for rapid decision-making, and in turn would enable the implementation of surveillance of a larger area. For the purpose of determining areas of interest, a hardware-software system for rapid radiological mapping will be developed, applicable in the future for installation in unmanned aerial vehicles, based on dosimetry detectors for measuring ambient dose equivalent, GPS receiver and compact central computer. The maximum area mapping speed will be correlated with the detector sensitivity and its response time. Field measurements will be carried out at least two research sites where in situ and laboratory gamma spectrometric measurements will be performed. Radiological measurements will be accompanied by the measurement of meteorological parameters that will enable the development of a correction pilot algorithm for specific meteorological and other physical environmental conditions of nuclear power plants.

Institute for Medical Research and Occupational Health (IMROH) is at the end of multiyear project: Research and Educational Centre of Environmental Health and Radiation Protection - Reconstruction and Expansion of the IMROH. At the end of the project, the Institute will be expanded with a new building of 6, 785.15 m2, while its existing building of 2, 067.41 m2 will be completely renovated. Radiation Protection Unit at the Institute specializes in radioecology and radiation protection, and it is continuously engaged in research of radioactive contamination of the environment by natural and fission radionuclides. This contribution presents new laboratories and current capabilities of Radiation Protection Unit at the Institute. Our new laboratories include three new coaxial HPGe gamma spectrometry systems with relative efficiencies up to 130%, electrically cooled in-situ HPGe detector, alpha and beta radiation counting systems, radon detectors, in-situ measurement instrumentation, H*(10) dosimeters for continuous monitoring, sample preparation systems and modelling simulation software solutions.

After a nuclear accident, it is important to quickly measure possible affected area to determine where emergency and remediation measures are needed. In situ gamma ray spectrometry was developed to quickly measure large areas of land following nuclear weapon tests and possible nuclear accidents. However, a proper calibration of detectors for in situ measurements is a long and complicated process. One tool designed to make this calibration quick is the InSiCal software. InSiCal software can shorten the in-situ calibration procedure to a single measurement (combined with calculations). We decided to investigate if the method can be implemented in Croatia, within expected constraints of emergency situations (especially time constrains). We compared in situ measurements made with two different HPGe detectors calibrated using the InSiCal software and laboratory measurements of samples collected at the same locations. Detector calibration and in situ measurements were optimized for quickness, simulating time pressure present in case of a nuclear accident. Measurements of both in-situ detectors were reasonably close – in most cases the confidence intervals overlapped. In-situ measurements generally undershot laboratory measurements. Large uncertainty intervals at energies below 100 keV make short in-situ measurements unsuitable in that energy range. If the range below 100 keV is important, the duration of the measurements must be increased. Our findings suggest that in situ gamma spectrometry using InSiCal software can provide reasonably accurate data, but some improvements may be needed.

Soil contributes significantly to both external and internal exposure to ionising radiation, via direct emission of gamma radiation and soil-to-plant radionuclide transfer, respectively. Next to primordial radionuclides, soil contains radionuclides dispersed during nuclear weapon testing and Chernobyl and Fukushima accidents, especially 137Cs. This motivated us to carry out a systematic research on the radioactivity of soil in Croatia, with a goal to obtain relevant data about the spread of 137Cs in Croatia, as well as about the primordial radionuclides. We had collected samples of the surface layer of uncultivated soil (0-10 cm) at 138 sites from all over the country and measured them for radionuclide activity concentrations by means of high-resolution gamma-ray spectrometry. This resulted in maps of the radioactivity of Croatian soil, containing data on activity concentrations of representative radionuclides in the environment. We focused on 137Cs, and also mapped 40K and radionuclides from 232Th and 238U decay chains. We found that the concentrations of 137Cs tended to increase with altitude, annual precipitation, and vegetation density. Activity concentrations of 40K were the highest in the Pannonian region. The ratio of the concentrations of 137Cs and K in soil, representing the potential for 137Cs entering food chains via uptake by plants, was the lowest in agriculturally important areas in the east of the Pannonian region. For both 232Th and 238U decay chains, activity concentrations were the highest in the Dinaric region, the lowest in the Pannonian region, and intermediate in the Adriatic region. In particular, relatively high concentrations of 226Ra in the soil of the Dinaric region implied a possibility of an enhanced emanation of its progeny 222Rn into the air. Activity concentrations of 210Pb were additionally elevated in areas with dense vegetation, most probably due to an atmospheric deposition of airborne 210Pb onto the surface of plants and their eventual decomposition on the ground. We used the obtained results on activity concentrations to calculate the related absorbed dose rate as a measure of external exposure to ionising radiation from soil. The sum of the absorbed dose rates for naturally occurring radionuclides and 137Cs showed that the external exposure was generally the highest in the Dinaric region and the Istrian Peninsula.

Due to the importance of safety, reliability and efficiency of dosimetry instrumentation, as well as increasing complexity of the technologies, we are proposing a method for early failure detection that could enable the necessary prompt response. IoT dosimetry sensors are usually required to operate for several years on a single battery and they are often installed in large numbers which place high energy and cost constraints. Therefore, the analysis and prediction itself is increasingly performed on devices that are close to the sensors. The concept of bringing analytical computational resources closer to the sensors themselves is called edge computing. In this work we will consider the application of machine learning for the purpose of fault detection in IoT dosimetry instrumentation as well as the various approaches with which these detections are realized with the help of edge computing devices.

Bioindicators are used for the detection of heavy metal pollution since the late 1960s on land and since the 1970s in the sea. Among different bioindicators, molluscs, especially mussels, are popular bioindicators of heavy metal pollution of waters. Mosses are among the more often used bioindicators of heavy metal pollution of air and soil. Mosses are well suited to be used as indicators of radioactive contamination. They receive water and nutrients predominantly through atmospheric deposition. Mosses have been proven to accumulate radionuclides from fallouts after nuclear tests and after the Chernobyl accident. We sampled moss at 26 locations in and around Papuk Nature Park and at 40 locations in and around Kopački Rit Nature Park. Using gamma-ray spectrometry, we measured radionuclides. Of special concern were two radionuclides: Cs-137, predominantly a result of the Chernobyl accident, and Pb-210, Rn-222 progeny and the only radionuclide in uranium or thorium decay chains with a half-life of more than days expected to be present in larger quantities in atmospheric deposition. The results show that the activity concentrations of Cs-137 measured in Papuk Nature Park and especially in Kopački Rit Nature Park are low compared to the activity concentrations of Cs- 137 measured at other locations in Europe, including Plitvice Lakes National Park. As for Pb- 210, the measured activity concentrations are largely in line with other measurements in Europe. We can conclude that especially Kopački Rit Nature Park, and to a lesser extent also Papuk Nature Park, can be considered places with very low Cs- 137 background, and as such a suitable detection site for atmospheric deposition of radionuclides even in cases of smaller of far-away accidents.

The Institute for Medical Research and Occupational Health (IMROH) is a multidisciplinary scientific institution with more than 70 years of experience in researching the mechanisms of action of various harmful chemical and physical factors and lifestyles on health and the environment. The Institute has a leading role in Croatia in research in the numerous fields that include dosimetry and protection against ionizing radiation, radiobiology, radiocontamination in the environment, as well as human exposure to these contaminants. Institute is at the end of multiyear project: Research and Educational Centre of Environmental Health and Radiation Protection - Reconstruction and Expansion of the IMROH. The purpose of this project is to increase and improve the current IMROH infrastructure and its research equipment, and with the accompanying organizational reform to establish a Research and Education Center for Health and Medical Ecology and Radiation Protection. Building appropriate spacious infrastructure and investing in modern scientific equipment will significantly increase the scientific excellence and visibility of IMROH in the field of existing research. This contribution gives in depth presentation of new laboratories and current capabilities of Radiation Dosimetry and Radiobiology Unit at the Institute. Unit has always played important role in Croatian scientific and professional areas dealing with radiation dosimetry, radiation protection and medical physics. This role will become strengthened with new laboratories that focus on novel technological developments in instrumentation and measurement methods as well as through acquisition of cutting-edge personal dosimetry systems and in-situ dosimetric instrumentation.

Radioaktivne tvari sastavni su dio atmosfere, njihovo je podrijetlo prirodno, kozmogeno ili terestrijalno. Od sredine dvadesetoga stoljeća u atmosferi su prisutne i radioaktivne tvari proizvedene djelovanjem ljudi. Praćenje i određivanje radioaktivnih tvari u Hrvatskoj započelo je još 1959. godine i provodi se neprekidno do danas. Prisutnost radioaktivnih tvari u zraku ispituje se mjerenjem ukupne beta aktivnosti, što je početni podatak ; želi li se saznati koji je od radionuklida prisutan u uzorku, provode se i posebne radiokemijske analize, alfa, beta i gamaspektrometrijskim metodama. Cilj ovoga rada je prodiskutirati povećanje vrijednosti ukupne beta aktivnosti zraka u svjetlu akcidenta ispuštanja 106Ru, beta emitera, iz proizvodnje u okoliš. Na lokaciji Instituta za medicinska istraživanja i medicinu rada (IMI) u Zagrebu neprekidno se i svakodnevno na visini jedan metar iznad tla prosisava zrak kroz filtar papir Schneider-Poelman, plavi. U okviru Državne mreže za trajno praćenje kvalitete zraka na mjernim postajama Zagreb-3, Kutina, Parg i Dugi Otok sakupljaju se uzorci PM10 frakcije lebdećih čestica. Dnevni uzorci PM10 frakcije lebdećih čestica sakupljaju se referentnim LVS (eng. Low Volume Sampler) sakupljačima volumnog protoka od 2, 3 m3 h-1 na Whatman QMA kvarcnim filtrima promjera 47 mm. Filtri i uzorci kondicionirani su u uvjetima temperature od 19 °C - 21 °C i relativne vlažnosti od 45 % - 50 %, sukladno standardu EN 12341. Vaganje je provedeno na mikro-vagi Mettler Toledo XP6/M. Za mjerenja ukupne beta aktivnosti korišteni su alikvotni uzorci filtra na kojima su sakupljene lebdeće čestice. U sakupljenom uzorku zraka najmanje 120 sati nakon uzorkovanja mjeri se ukupna beta aktivnost u beta brojaču niskih aktivnosti Low-level beta GM multicounter system ; model RISØ GM-25-5. Kalibracija efikasnosti provedena je standardima Češkog metrološkog instituta. U ovom su radu prikazani rezultati određivanja ukupne beta aktivnosti zraka u uzorcima PM10 frakcije lebdećih čestica sakupljenima krajem rujna i početkom listopada 2017. godine. Rezultati sa svih mjernih postaja su međusobno uspoređeni. Vrijednosti ukupne beta aktivnosti povaćale su se u svim uzorcima zraka već od 30. rujna, da bi se maksimalne vrijednosti postigle 1. listopada (ukupne lebdeće čestice u Zagreb- IMI: 119 mBqm-3 ; te PM10 frakcije lebdećih čestica, Kutina: 100 mBq m-3 ; Zagreb-3: 85 mBq m-3 ; Parg: 95 mBq m-3) i 2. listopada na Dugom Otoku: 56 mBqm-3. Nad Hrvatskom se oblak rutenija nadvio sa sjeveroistoka prema jugozapadu i onečišćenje je trajalo do najviše pet dana. Vrijednosti ukupne beta aktivnosti zraka vratile su se na one slične prosječnim, uobičajenim vrijednostima za pojedinu lokaciju, već od 4. do 6. listopada (oko i ispod 1 mBq m- 3). Srećom, sve izmjerene vrijednosti bile su ispod intervencijskih nivoa i nisu zahtijevale zaštitne mjere.

Red mud is a by-product obtained by processing bauxite ore during alumina production. Based on chemical and morphological characteristics, red mud shows good potential for use as building material. Since red mud is of natural origin, the presence of radionuclides in such material is expected, which in increased concentration can cause damage to human health. As part of this research, the activity concentration of radionuclides in a red mud sample from Dobro Selo near Mostar (BiH) was examined by high- resolution gamma spectrometry. In addition to red mud, concentration of radionuclides in fly ash sample from the Tuzla thermal power plant (BiH) and in commercial cement from Holcim, Koromačno (CRO) were also examined for the purpose of comparing red mud with materials already used as construction materials.

Praćenje i kvantifikacija radioaktivnih tvari u zraku započelo je u Hrvatskoj 1961. godine i provodi se neprekidno sve do danas u Jedinici za zaštitu od zračenja Instituta za medicinska istraživanja i medicinu rada, a u sklopu programa praćenja radioaktivnosti okoliša. Jedinica za zaštitu od zračenja dio je Europske mreže laboratorija ''Ring of 5 – Ro5'' koji imaju kapacitete za rano otkrivanje radionuklida u zraku. Kvantifikacija radioaktivnosti u zraku provodi se visokorezolucijskom gamaspektrometrijom, metodom koja je akreditirana prema zahtjevima norme HRN EN ISO/IEC 17025:2017. Kalibracija energije i efikasnosti gamaspektrometra provedena je uz pomoć kalibracijskih izvora (standarda) Češkog metrološkog instituta koji pokrivaju energiju između 40 i 2500 keV. Uzorci zraka dobivaju se pumpanjem velikog volumena zraka kroz Petrianov filtar (FPP-15-1.5) smješten na 1, 5 m iznad tla te korištenjem ASS-500 HVS (High Volume Sampler ASS-500) stanice. U razdoblju 29.9.-9.10.2017. godine izmjerene su koncentracije aktivnosti 106Ru iznad granice detekcije u uzorcima zraka uzorkovanog na lokaciji Instituta za medicinska istraživanja i medicinu rada u Zagrebu. Prosječna koncentracije aktivnosti 106Ru u zraku u navedenom razdoblju u Zagrebu bila je 1, 33∙10-2 Bqm-3. Analizom svih podataka izmjerenih u laboratorijima mreže Ro5 određeno je mjesto ispuštanja 106Ru kao i njegovo rasprostiranje Europom. U studenome 2017. godine Međunarodna agencija za atomsku energiju (IAEA) je objavila da je došlo do nekontroliranog ispuštanja 106Ru. Sve članice IAEA su potvrdile da je to točno ali niti jedna nije preuzela odgovornost. Detaljnom analizom podataka mreže Ro5 u sklopu kojih su i podaci iz IMI-ja došlo se do zaključka da je ispuštanje bilo u Rusiji a o tome je objavljen i znanstveni rad.