Biomaterial Database

Epiphytic fruticose lichens as biomonitors for retrospective evaluation of the (134)Cs/(137)Cs ratio in Fukushima fallout. 2014

V Ramzaev, and A Barkovsky, and A Gromov, and S Ivanov, and M Kaduka

Saint-Petersburg Research Institute of Radiation Hygiene after professor P.V. Ramzaev, Mira Str. 8, 197101 St.-Petersburg, Russia. Electronic address: V.Ramzaev@mail.ru.

In 2011-2013, sampling of epiphytic fruticose lichens of the genera Usnea, Bryoria and Alectoria was carried out on Sakhalin and Kuril Islands (the Sakhalin region, Russia) to investigate contamination of these organisms with the Fukushima-derived (134)Cs and (137)Cs. Activities of the radionuclides were determined in all 56 samples of lichens taken for the analysis. After correction for radioactive decay (on 15 March 2011), the activity concentrations ranged from 2.1 Bq kg(-1) (d.w.) to 52 Bq kg(-1) for (134)Cs and from 2.3 Bq kg(-1) to 52 Bq kg(-1) for (137)Cs. Cesium-134 and (137)Cs activities for the whole set of lichens (n = 56) were strongly positively correlated; Spearman's rank correlation coefficient was calculated as 0.991 (P < 0.01). The activity concentrations of (134)Cs and (137)Cs in Usnea lichens from the Sakhalin and Kunashir islands declined with a factor of three in the period from 2011 to 2013. The average biological half-time for both cesium radionuclides in lichens of the genus Usnea is estimated as 1.3 y. The mean of 0.99 ± 0.10 and median of 0.99 were calculated for the decay corrected (134)Cs/(137)Cs activities ratios in the lichens (n = 56). The radionuclides ratio in the lichens did not depend on location of sampling site, species and the time that had passed after the Fukushima accident. The regression analysis has shown the background pre-Fukushima level of (137)Cs of 0.4 ± 0.3 Bq kg(-1), whereas the ratio between the Fukushima-borne (134)Cs and (137)Cs in the lichens was estimated as 1.04. The (134)Cs/(137)Cs activities ratio in lichens from the Sakhalin region is consistent with the ratios reported by others for the heavy contaminated areas on Honshu Island in Japan following the Fukushima accident. The activity concentrations of natural (7)Be in lichens from the Sakhalin region varied between 100 Bq kg(-1) and 600 Bq kg(-1); the activity concentrations did not exhibit temporal variations during a 2y-period of observations. The applicability of epiphytic fruticose lichens as retrospective bio-monitors for the air-borne radiocesium contamination of the environment is discussed.

UI	MeSH Term	Description	Entries
D008011	Lichens	Any of a group of plants formed by a symbiotic combination of a fungus with an algae or CYANOBACTERIA, and sometimes both. The fungal component makes up the bulk of the lichen and forms the basis for its name.	Lichen
D011834	Radiation Monitoring	The observation, either continuously or at intervals, of the levels of radiation in a given area, generally for the purpose of assuring that they have not exceeded prescribed amounts or, in case of radiation already present in the area, assuring that the levels have returned to those meeting acceptable safety standards.	Monitoring, Radiation
D002586	Cesium	A member of the alkali metals. It has an atomic symbol Cs, atomic number 55, and atomic weight 132.91. Cesium has many industrial applications, including the construction of atomic clocks based on its atomic vibrational frequency.	Caesium,Caesium-133,Cesium-133,Caesium 133,Cesium 133
D002588	Cesium Radioisotopes	Unstable isotopes of cesium that decay or disintegrate emitting radiation. Cs atoms with atomic weights of 123, 125-132, and 134-145 are radioactive cesium isotopes.	Radioisotopes, Cesium
D000396	Air Pollutants, Radioactive	Pollutants present in air which exhibit radioactivity.	Radioactive Air Pollutants,Pollutants, Radioactive Air
D012189	Retrospective Studies	Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.	Retrospective Study,Studies, Retrospective,Study, Retrospective
D012426	Russia	A country located in north Asia bordering the Arctic Ocean, extending from Europe (the portion west of the Urals) to the North Pacific Ocean. The capital is Moscow.	Russian S.F.S.R.,Russian Federation (Europe),Russian SFSR
D062406	Fukushima Nuclear Accident	Nuclear power accident that occurred following the Tohoku-Kanto earthquake of March 11, 2011 in the northern region of Japan.	Fukushima Nuclear Accident, Japan,Fukushima Nuclear Disaster,Accidents, Fukushima Nuclear,Disaster, Fukushima Nuclear,Disasters, Fukushima Nuclear,Fukushima Nuclear Accidents,Fukushima Nuclear Disasters,Nuclear Accident, Fukushima,Nuclear Accidents, Fukushima,Nuclear Disaster, Fukushima,Nuclear Disasters, Fukushima
D020949	Usnea	A genus of lichen-forming fungi containing usnic acid and mucilage. Usnea barbata is used in HERBAL MEDICINE.	Usnea barbata