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Za određivanje 210Pb u organskim uzorcima malih masa, analiza uporabom beta brojača je često potrebna da bi se postigle željene granice detekcije. Za beta brojanje je pak potrebna radiokemijska separacija 210Pb od intereferirajućih radionuklida. U tu svrhu moguće je koristiti različite smole. U ovom istraživanju, napravljena je usporedba dviju smola: Sr smola, kao poznati krunasti eter korišten u radiokemijskim analizama više radionuklida te AnaLig®Sr-01, materijal temeljen na molekularnom raspoznavanju, a koji je manje zastupljen u radiokemiji. Obje vrsta smola, incijalno proizvedene za separaciju Sr, čvrsto vežu Pb iz različitih kiselih otopina. Stoga su ove dvije vrste smole ispitane na istoj vrsti organskog uzorka (uzorci gujavica) da bi se usporedile njihove mogućnosti izolacije 210Pb. Separacija 210Pb na Sr smoli je napravljena metodom opisanom u Štrok i Smodiš (2011), a na AnaLig Sr-01 smoli metodom Dulanska et al. (2011) koja je za potrebe ovog istraživanja bila modificirana. Prije radiokemijske separacije uzorcima je dodana poznata količina Pb nosača, a potom su razoreni mješavinom HNO3/HCl/H2O2 uz zagrijavanje. Uzorci su na obje smole naneseni u 2M HCl otopini. Sr smola je korištena samo jednom za svaki uzorak, dok je AnaLig smola regenerirana vodom i alkalnom otopinom EDTA. U obje metode 210Pb je taložen u obliku PbSO4, a kemijsko iskorištenje je određeno gravimetrijski. Dodatno, potencijalni gubitak Pb na AnaLig smoli je popraćen njegovim određivanjem u uzorku prije i poslije kolone uz pomoć atomskog apsorpcijskog spektrometra (AAS). Uzorci su čuvani 30 dana prije brojanja proporcionalnim beta brojačem. Na Sr smoli je analizirano ukupno 18 uzoraka, a na AnaLig smoli 9. Uzorci su bili u rasponu masa 0.04 – 0.62 g suhe tvari. Na Sr smoli, kemijsko iskorištenje je bilo u rasponu 16 – 35 %, s prosječnom vrijednosti od 22%. Na AnaLig®Sr-01 smoli gravimetrijski određeno iskorištenje je bilo u rasponu 16 – 90 %, prosječne vrijednosti 70 %. Međutim, iskorištenje određeno AAS-om je bilo u rasponu 63 – 100 %, s prosječnom vrijednosti od 87 %. Razlike između gravimetrijski i spektrometrijski određenog iskorištenja upućuju na postojanost AnaLig smole prilikom opetovane upotrebe, dok su dodatni gubici Pb mogući tijekom njegove depozicije u obliku sulfata. Osim većih kemijskih iskorištenja, otprilike tri puta manje količine reagensa su bile potrebne za separaciju 210Pb na AnaLig®Sr-01 u odnosu na Sr smolu.

Jedan od ciljeva HrZZ projekta RiChFALL je istraživanje prijenosa radionuklida iz tla u razne poljoprivredne kulture uzgojene na lokalnim poljoprivrednim gospodarstvima. 210Po je prirodno prisutni radionuklid koji zajedno s 210Pb znatno doprinosi unutarnjoj izloženosti ionizirajućem zračenju u ljudi. Isto tako, varijacije u količinama 210Pb i 210Po u tlu mogu biti odraz prirodnih biogeokemijskih procesa kao i antropogenih utjecaja različitih industrijskih aktivnosti. I dok aktivnost 210Pb u uzorcima tla može biti direktno izmjerena gamma spektrometrijom, određivanje aktivnosti 210Po zahtijeva radiokemijsku pripremu uzorka prije mjerenja alfa spektrometrom. Uzorci tla su bili prikupljeni iz različitih hrvatskih regija. Uz pomoć korera uzimani su na dubinama: 0 – 5 cm, 5 – 10 cm, 10 – 20 cm te 20 – 50 cm, a potom sušeni na temperaturi do 65 °C da bi se izbjegli gubici 210Po prilikom zagrijavanja. Posušeni uzorci su homogenizirani te mehanički prosijani na veličinu čestica od 250 µm. Razaranje uzoraka tla je napravljeno uz pomoć mikrovalne pećnice. Uzimajući u obzir volatilnost 210Po, standardna procedura za mirkovalno razaranje tla je bila malo prilagođena. Masa uzorka je bila otprilike 1g. Neposredno prije mikrovalne digestije u uzorke je dodan tracer 209Po, isto alfa emiter. Nakon razaranja, uzorci su profiltrirani te je filtrat pažljivo uparen do suhoga. Preostali talog je otopljen u 0.5 M HCl otopini uz dodatak potrebne količine askorbinske kiseline. U ovoj otopini napravljena je auto- depozicija Po na srebrni disk, uz pomoć zagrijavanja i miješanja. Raspon kemijskog iskorištenja je bio 80 – 95 %. Koncentracije aktivnosti 210Po u uzorcima tla varirale su od nekoliko desetaka pa do nekoliko stotina Bqkg-1. Najveće vrijednosti izmjerene su u površinskim slojevima tla (do 10 cm dubine). Međutim, distribucija 210Po između prvog (0 – 5 cm) i drugog sloja (5 – 10 cm) je varirala, a na nekim lokacijama je upravo drugi sloj imao veće koncentracije aktivnosti 210Po od prvog. U trećem sloju (10 – 20 cm) vrijednosti su najčešće bile nešto niže od onih izmjerenih u površinskim slojevima. No zato u najdubljem sloju (20 – 50 cm) je zabilježen najveći pad u koncentracijama aktivnosti 210Po u svim izmjerenim tlima. Isto tako, 210Po nije nužno bio u ravnoteži s 210Pb u svim uzorcima. Daljna elementna analiza i analiza fizikalno-kemijskih parametera prikupljenih uzoraka mogla bi pomoći u identifikaciji onih faktora koji utječu na dinamiku te distribuciju 210Pb i 210Po u tlima.

Natural radionuclides can be concentrated in coal ash and slag. When such a waste is deposited in the envi- ronment, it is normally inhabited by different animals and plants. Earthworms are one of the most exposed as they live in close contact with such a waste throughout their entire life. Po-210 and Pb-210 represent one of the most radiotoxic radionuclides, especially when ingested. Within this study we wanted to assess the uptake of Po-210 and Pb-210 by earthworm Eisenia fetida transplanted on the coal ash and slag sampled from the former chemical factory in Kaštela Bay (Croatia). Uptake was compared with cultivation on non-contaminated and reference soil. After cultivation period of 28 days, earthworm samples were cleaned. From one set of samples, which was used also for cytotoxic and genotoxic investigations, coelomic fluid was removed and from other not. They were dried at 65 °C. Then the samples were digested and Po was spontaneously deposited on Ag disc and Po-210 activity concentration was determined by alpha-particle spectrometry. Pb-210 was separated using Sr Resin column and measured by gas-flow proportional counter. Results show that Po-210 activity concentrations in earthworms cultivated on coal ash and slag were in the range of 43-93 Bq/kg, whereas on non-contaminated and reference soil values were in the range of 17-39 Bq/kg. Therefore, Po-210 activity con- centrations found in earthworms cultivated on coal ash and slag are 2-3 times higher compared to control group. Similar observation was found for Pb-210 only for samples without coelomic fluid, where samples with coelomic fluid did not show any significant difference between those cultivated on coal ash and slag and control ones. This indicates different distribution of Pb-210 and Po-210 between coelomic fluid and other earthworm’s body compartments.

Industrial residues and wastes with higher content of naturally occurring radionuclides represent a potential ecological risk to the biota residing in the vicinity of the disposal sites. Coal ash and slag landfills are widespread due to usage of coal as fuel in thermal power plants worldwide. Combustion of coal results in preconcentration of radionuclides naturally present in coal in its residual ash as well as the spread of the ash particles at greater distances. Earthworms represent one of the most important group of terrestrial organisms and are therefore often used in ecotoxicological studies. The aim of this study was to determine the influence of weathered coal ash and slag with enhanced content of radionuclides from uranium decay chain that were sampled in the area of the former chemical factory in Kaštela Bay (Croatia), on biochemical markers (protein, lipid and carbohydrate content, lipid peroxidation, GST and AChE activity), genotoxicity markers (Comet assay and micronucleus test), cytotoxicity (neutral red uptake assay) and reproduction of the earthworm Eisenia fetida. The results have shown that 28 days exposure to those substrates cause oxidative stress, genotoxic and cytotoxic effects and inhibit reproduction. Compared to the control samples, earthworms exposed to the coal ash had significantly higher activity concentrations of Po-210, a member of uranium decay chain and one of the most radiotoxic naturally occurring radionuclide. Coelomic fluid expression had no significant impact on the activity concentrations of Po-210 in earthworms, indicating that polonium is mostly deposited in the soft tissues.

Tritium (3H) as a constituent of the water molecule is an important natural tracer in hydrological sciences. The anthropogenic tritium introduced into the atmosphere unintentionally became an excellent tracer of processes on a time scale of up to 100 years. A prerequisite for tritium applications is to know the distribution of tritium activity in precipitation. Here we present a database of isoscapes derived from 41 stations for amount-weighted annual mean tritium activity in precipitation for the period 1976 to 2017 on spatially continuous interpolated 1 km×1 km grids for the Adriatic–Pannonian region (called the AP3H_v1 database), with a special focus on post-2010 years, which are not represented by existing global models. Five stations were used for out-of-sample evaluation of the model performance, independently confirming its capability of reproducing the spatiotemporal tritium variability in the region. The AP3H database is capable of providing reliable spatiotemporal input for hydrogeological application at any place within Slovenia, Hungary, and their surroundings. Results also show a decrease in the average spatial representativity of the stations regarding tritium activity in precipitation from ∼440 km in 1970s, when bomb tritium still prevailed in precipitation, to ∼235 km in the 2010s. The post-2010 isoscapes can serve as benchmarks for background tritium activity for the region, helping to determine potential future local increases in technogenic tritium from these backgrounds. The gridded tritium isoscape is available in NetCDF-4 at https://doi.org/10.1594/PANGAEA.896938 (Kern et al., 2019).