Puutavaran radioaktiivisuus Suomessa : Ympäristön säteilyvalvonnan toimintaohjelma

Puutavaran sisältämän radioaktiivisen cesiumin lähettämä gammasäteily voi maksimissaan aiheuttaa 0,03 millisievertin vuotuisen annoksen hirsitalossa asuville. Luonnon radioaktiivisuudesta johtuva ulkoisen gammasäteilyn aiheuttama annos puutalossa asuville on kertaluokkaa pienempi. Kotimaisen puutavaran käyttöä ei tarvitse rajoittaa puuaineksen 137Cs-pitoisuuksien takia. Puutavara sisältää pääasiassa Tšernobylin ydinvoimalaonnettomuuden laskeumasta vuodelta 1986 peräisin olevaa radioaktiivista cesiumia (137Cs). Cesiumia (137Cs) kulkeutuu pitkällä aikavälillä maaperästä puustoon ravinteiden ja veden otossa. Lisäksi puussa on vähäisessä määrin luonnon radioaktiivisia aineita, joita ovat uraanin ja toriumin (238U ja 232Th) hajoamissarjoihin kuuluvat radionuklidit sekä kaliumin radioaktiivinen isotooppi (40K). Projektin avulla saatiin ajantasainen tilannekuva cesium-137:n aktiivisuuspitoisuuksista kotimaisessa puutavarassa. Valituista näytteistä määritettiin myös edellä mainitut luonnon radioaktiiviset aineet. Metsäteollisuus toimitti projektia varten näytteet puutavaran vastaanoton yhteydessä. Näytteitä saatiin 59 kunnasta pääasiassa Etelä- ja Keski-Suomesta, alueilta, joihin tuli eniten Tšernobyl-laskeumaa. Tutkittavat puulajit olivat kuusi, mänty ja koivu. Kuoritun puuaineksen 137Cs-aktiivisuuspitoisuus vaihteli välillä 0,1 – 97 Bq/kg (80 %:n kuiva-ainepitoisuutta kohti) riippuen puun alkuperäkunnan laskeuman aktiivisuudesta. Pitoisuuksien hajontaa selittää osaltaan se, että metsien kasvuolosuhteet vaikuttavat cesiumin kertymiseen puuhun. Siten pitoisuus voi vaihdella samassakin kunnassa. Cesiumpitoisuuden vaihtelu puulajien välillä ei ollut tilastollisesti merkitsevää. Kuoressa pitoisuus oli 10 – 766 Bq/kg (80 % k.p.) puulajista ja laskeuma-alueesta riippuen. Puutavarassa mitatuissa luonnon radionuklidipitoisuuksissa ei havaittu oletusarvoista poikkeavia tuloksia. Säteilyturvakeskuksessa toteutettiin vuosina 2013 – 2014 projekti ”Puutavaran radioaktiivisuus Suomessa”. Projekti oli osa STUKin ympäristön säteilyvalvontaohjelmaa. Tarve projektin käynnistämiselle oli ilmeinen, sillä edellisen kerran valtakunnallinen puutavaran radioaktiivisuustutkimus oli tehty 1990-luvulla

Patterns of vertical cyst distribution and survival in 100-year-old sediment archives of three spring dinoflagellate species from the Northern Baltic Sea

The history of expansion of bloom-forming cold water dinoflagellates in the Northern Baltic Sea was studied using 100-year-old sediment archives of their resting cysts. Vertical cyst distributions of Biecheleria baltica and Apocalathium malmogiense, two dinoflagellates indistinguishable by light microscopy and not recognized as distinct species in monitoring, and chain-forming Peridiniella catenata were analysed in Pb210 and Cs137 dated layers of a sediment core from deep, hypoxic accumulation bottoms of the Gulf of Finland. Cyst profiles showed that B. baltica and A. malmogiense were already present in the Baltic spring phytoplankton community at the beginning of the 20th century. This confirms that B. baltica, which was only recognized in the late 1980s, is a native species in the area. A drastic increase in B. baltica cyst concentrations in the 1930s to 1960s coincided with the acceleration of anthropogenic eutrophication. Large cyst deposits accumulated over several decades in the sediment which, by the 1980s, amounted to the seed stock necessary to inoculate dominant blooms. In the cyst records A. malmogiense always contributed a minor fraction of the two species. P. catenata had a relatively short cyst record in Gulf of Finland sediments despite demonstrated long-term presence in the plankton, which emphasizes that cyst-based historic surveys are not suitable for all cyst-forming dinoflagellates. This was corroborated by correspondence analyses of long-term plankton and cyst records which validated the trends from the sediment archive for B. baltica and A. malmogiense, but failed to do so for P. catenata. Germination experiments with 100-year-old cysts revealed a remarkable long-term survival capacity of A. malmogiense, making this species a suitable model for resurrection studies testing adaptation in heavily impacted systems such as the Baltic Sea

Common Inflammation-Related Candidate Gene Variants and Acute Kidney Injury in 2647 Critically Ill Finnish Patients

Acute kidney injury (AKI) is a syndrome with high incidence among the critically ill. Because the clinical variables and currently used biomarkers have failed to predict the individual susceptibility to AKI, candidate gene variants for the trait have been studied. Studies about genetic predisposition to AKI have been mainly underpowered and of moderate quality. We report the association study of 27 genetic variants in a cohort of Finnish critically ill patients, focusing on the replication of associations detected with variants in genes related to inflammation, cell survival, or circulation. In this prospective, observational Finnish Acute Kidney Injury (FINNAKI) study, 2647 patients without chronic kidney disease were genotyped. We defined AKI according to Kidney Disease: Improving Global Outcomes (KDIGO) criteria. We compared severe AKI (Stages 2 and 3, n = 625) to controls (Stage 0, n = 1582). For genotyping we used iPLEX(TM) Assay (Agena Bioscience). We performed the association analyses with PLINK software, using an additive genetic model in logistic regression. Despite the numerous, although contradictory, studies about association between polymorphisms rs1800629 in TNFA and rs1800896 in IL10 and AKI, we found no association (odds ratios 1.06 (95% CI 0.89-1.28, p = 0.51) and 0.92 (95% CI 0.80-1.05, p = 0.20), respectively). Adjusting for confounders did not change the results. To conclude, we could not confirm the associations reported in previous studies in a cohort of critically ill patients.Peer reviewe

Heme oxygenase-1 repeat polymorphism in septic acute kidney injury

Acute kidney injury (AKI) is a syndrome that frequently affects the critically ill. Recently, an increased number of dinucleotide repeats in the HMOX1 gene were reported to associate with development of AKI in cardiac surgery. We aimed to test the replicability of this finding in a Finnish cohort of critically ill septic patients. This multicenter study was part of the national FINNAKI study. We genotyped 300 patients with severe AKI (KDIGO 2 or 3) and 353 controls without AKI (KDIGO 0) for the guanine-thymine (GTn) repeat in the promoter region of the HMOX1 gene. The allele calling was based on the number of repeats, the cut off being 27 repeats in the S-L (short to long) classification, and 27 and 34 repeats for the S-M-L2 (short to medium to very long) classification. The plasma concentrations of heme oxygenase-1 (HO-1) enzyme were measured on admission. The allele distribution in our patients was similar to that published previously, with peaks at 23 and 30 repeats. The S-allele increases AKI risk. An adjusted OR was 1.30 for each S-allele in an additive genetic model (95% CI 1.01-1.66; p = 0.041). Alleles with a repeat number greater than 34 were significantly associated with lower HO-1 concentration (p<0.001). In septic patients, we report an association between a short repeat in HMOX1 and AKI risk

Transfer factors and effective half-lives of 134Cs and 137Cs in different environmental sample types obtained from Northern Finland: case Fukushima accident

Tutkimuksella selvitettiin Fukushiman ydinvoimalaitoksen onnettomuuden vaikutuksia Lapin ympäristön tilaan Fukushiman ydinvoimalaitosonnettomuus vuonna 2011 aiheutti cesium-laskeumaa ympäri maapalloa. Lapissa vuosina 2011 – 2013 kerätyissä ympäristönäytteissä näkyi cesium-137:n lisäksi pieniä määriä cesium-134:ää, minkä voitiin olettaa olevan peräisin Fukushiman onnettomuudesta. Määrät olivat hyvin pieniä, noin yksi bequerelliä neliömetrillä. Ennen Fukushiman onnettomuutta Lapissa kerätyissä ympäristönäytteissä ei kuitenkaan oltu havaittu cesium-134:ää sitten 2000-luvun vaihteen. Näiden cesium-isotooppien suhteen perusteella pystyttiin arvioimaan, että onnettomuudesta aiheutui pieni, vain 0,3 – 5 prosentin lisäys cesium-137-laskeuman tasoon. Suurin lisäys havaittiin havupuiden oksilla kasvavassa ilmansaasteille herkässä sammallajissa lupossa. Mittausten avulla pystyttiin arvioimaan, miten tehokkaasti cesium kertyy laskeumasta muihin mitattuihin ympäristönäytteisiin. Tämän tutkimuksen mukaan cesium siirtyi tehokkaimmin poron ja suden lihaan. Tutkimuksen tulokset ovat sopusoinnissa Tšernobyl-laskeuman perusteella aiemmin tehtyjen arviointien kanssa

The impact of different atmospheric phenomena to cosmogenic ²² Na/⁷Be ratio

Abstract The isotopic ratio of two cosmogenic isotopes, ²²Na and ⁷Be, has been recognized as a possible tracer for atmospheric dynamics. We studied how different atmospheric phenomena affect the ²²Na/⁷Be ratio that are known to affect the ground level ⁷Be concentrations. The ²²Na/7Be ratio was studied in the following context: estimation of aerosol residence time, in the intrusions of stratospheric air after Sudden Stratospheric Warming (SSW) events, seasonal variations due to different atmospheric mixing conditions and finally the interannual variations caused by the large-scale atmospheric circulation such as North Atlantic Oscillation (NAO), Arctic Oscillation (AO), Scandinavian Pattern (SCAND) and Quasi-Biennial Oscillation (QBO). This study utilized airborne radioactivity monitoring data from three Finnish stations located in Rovaniemi (66.51 °N, 25.73 °E), Kajaani (64.08 °N, 27.71 °E) and Kotka (60.48 °N, 26.92 °E). The theoretical calculations were performed to see how the ²²Na/⁷Be ratio changes as a function of altitude during when produced by the galactic cosmic rays. The calculations showed that the ²²Na/⁷Be ratio is higher in the stratosphere and lower in the troposphere. At mid-stratosphere level the ratio was 0.001, at tropopause level approximately 0.0007 and at ground level approximately 0.00045. Due to the different half-lives of 22Na and ⁷Be the mean atmospheric residence time can be estimefrom the radioactive decay law by assuming an initial activity concentration ratio of 0.0007 and using the measured ground level ²²Na/⁷Be ratios. This resulted in the median atmospheric residence time as 91–95 days. The atmospheric impact on ²²Na/⁷Be ratio was studied at different time scales starting from short-term impact from SSW, the known seasonal cycle and variations at interannual timescale. SSW events caused rapid increases in the ground level ⁷Be and ²²Na concentrations while the impact on ²²Na/⁷Be ratio was relatively small. A clear seasonal cycle in the ²²Na/⁷Be ratio was observed where the ²²Na/⁷Be ratio was at low value during November–February, increased during March–May, stayed at stable high value during June–July and steadily decreased during August–October. The long-term average for ²²Na/7Be ratio was established to be 1.1 × 10⁻⁴ by using the Kotka data from 1993 to 2020. During 1995–2009, the ²²Na/⁷Be ratio was below the long-term average, and during 2010–2020, generally above. The interannual variations in the ²²Na/⁷Be ratio were studied by using wavelet transform analysis of the Kotka data. The analysis showed 4–6-year and 11-year periodicities. The wavelet coherence analyses with AO, NAO, SCAND, QBO and Southern Oscillation (SO) indices showed that the shorter periodicity was caused by the NAO/AO effects the atmospheric circulation in Scandinavia and hence the transport of the isotopes from upper atmosphere to ground level. The observed coherence with the Southern Oscillation Index (SOI) starting from 2012 onwards appeared at an approximately 3–4 year scale while the AO and NAO had a coherence at an approximately 6-year scale. The observed 11-year periodicity was caused by the Solar cycle which modulates the ⁷Be and ²²Na production in the upper atmosphere