A. ^u~ulovi}, et al.: Natu ral Radionuclides and 137Cs in Moss and Lichen ... 44 Nuclea r Technol ogy & Ra dia tion Pro tection: Year 2012, Vol. 27, No. 1, pp. 44-51

NATU R AL RADIONUCLIDES AND 137Cs IN MOSS AND LICHEN IN EASTERN

by

Ana ^U^ULOVI] 1, Dragana POPOVI] 2*, Rodoljub ^U^ULOVI] 3, and Jelena AJTI] 2

1 In sti tute for Ap pli ca tion of Nu clear En ergy INEP, Uni ver sity of Bel grade, Bel grade, Ser bia 2 Fac ulty of Vet er i nary Med i cine, Uni ver sity of Bel grade, Bel grade, Ser bia 3 Fac ulty for Ap plied Ecol ogy Futura, Singidunum Uni ver sity, Bel grade, Ser bia

Sci en tific pa per DOI: 10.2298/NTRP1201044^

The pa per pres ents the re sults of radionuclides de ter mi na tion in moss (Homolothecium sp., Hypnum Cupressiforme sp., and Brachythecium sp.) and li chen (Cladonia sp.) sam pled in the re - gion of Eastern Serbia during 1996-2010. The ac tivi ties in moss are in the range of 100-500 Bq/kg d. w. for 40K, and 5-50 Bq/kg d. w. for 226Ra and 232Th, while the “soil-to-moss” trans fer fac tors are 0.45 for 40K, 3 for 226Ra, and 0.3 for 232Th. The spa tial dis tri bu tion of the 137Cs ac- tiv i ties is highly non-uni form; some val ues reach 500 Bq/kg d. w., with less than 10% of the sam ples, mainly the ones taken prior to 2000, with the ac tiv ity above 1000 Bq/kg d. w. The vari - a tions in the con tent of nat u ral radionuclides among the moss spe cies are not sig nif i cant. The fre quency pat tern of the ac tiv i ties of nat u ral radionuclides in li chen is sim i lar to the one in moss, but the ac tiv i ties in li chen are to some ex tent lower. The mean ac tiv ity of 137Cs in li chen is below 400 Bq/kg d. w. The mean ac tiv ities of 7Be in moss and lichen sampled in 2006 and 2008 are in the range of 41-122 Bq/kg d. w., with pro nounced vari a tions be tween the sam pling sites. Key words: moss, li chen, radionuclides, East ern Ser bia

IN TRO DUC TION method is also used to identi fy sources of heavy metals pol lu tion, such as ore ex ploi ta tion, ag ri cul tural ac tiv i - In the last sev eral de cades, moss and lichen have ties, etc. [13-15]. been es tab lished as re li able bioindicators of ra dio ac tiv ity The lichen indi ca tor method is suitable for de- in the envi ron m ent, since they have no root ing system tec tion of long-term at mo spheric con tam i na tion by and the content of el em ents in them is gener all y due to ura nium and other heavy metals, as lichen ac cu mu - pre cip i ta tion and dry de po si tion. Nat u ral radionuclides lates ura nium and other el em ents and retai ns them for in both specie s are mostly accu m ulat ed by resuspension sev eral years af ter the source of pol lu tion has been ex - of soil and dust from soil and vege ta ti on cover. Moss and hausted [16-20]. Concen tra tions of radionuclides and li chen have been often used in dif ferent studies on global heavy metals are sig nif icantly higher in lichen thallus de po si tion of radionuclides from nu clear at mo spheric than in vari ous or gans of higher plants [21]. Moss and tests, mon i tor ing of radiocontamination fol low ing nu - li chen have sig nif i cantly dif fer ent soil-to-plant trans - 226 clear plant ac ci dents, and ra dio ac tiv ity and pol lu tion fer fac tors than higher plants: 2.3 and 43.8 for Ra 137 40 moni tor ing in the vi cinit y of ura nium plants [1-7]. Fur- and Cs, respec tively, but only 0.5 for K, which is ther, moss and lichen have been used in studies on con- less than for higher plants [22]. tam i na tion by de pleted ura nium am mu ni tion in Po tas sium-40 is a pri mor dial nat u ral radionuclide 9 and Metohia and Southern Serbia [8], as well as in with a long half-life of 1.25×10 years, and a bio log i cal Bosnia and Herzegovina [9]. half-life of 30 days. It com prises around 0.0119% of the The moss method was first used in the Scandi na - total potas sium, which is found in large amounts in vian countri es as a com plem entar y method to classic soils, plants, ani m als and hum ans. It is most abundant in stru men ta tion pol lu tion mon i tor ing [10-12]. To day, among natu ral radionuclides, and it is a chem ical ana - moss biomonitoring is a part of pol luti on moni tor ing logue to cae sium. programmes in most of the Euro pean countri es as it Natu ral thorium -232 is also a long lived 6 gives evi dence of anthropogenic im pact in urban areas radionuclide (half-life 1.6×10 years). 238 due to ve hicu lar traf fic and fossil fuel com busti on. The The half-life of radium -226, a daughter of U, is 1600 years. Ra dium-226 is found in dif ferent quan - ti ties in soils and rocks contai ning nat ural uranium . Its * Cor re spond ing au thor; e-mail: [email protected] bio log i cal half-life is up to 45 years [23]. A. ^u~ulovi}, et al.: Natu ral Radionuclides and 137Cs in Moss and Lichen ... Nuclea r Technol ogy & Ra dia tion Pro tection: Year 2012, Vol. 27, No. 1, pp. 44-51 45

Beryl lium-7 (half-life 53.28 days) is produced by cosm ic rays in spallation proces ses in the upper tro- posphere and lower stratosphere . Its vari ati ons in mean annual con cen tra tions in air reflect changes in its atm ospheri c produc ti on rate, and its seasonal patter ns are cor re lated to the strato sphere-tro po sphere ex - change, verti cal mixing within the tropo sphere and pre cip i ta tion. 7Be is widely used as an indi ca tor of at- mo spheric trans port pro cesses. In mid-lat i tudes, the 7Be seasonal vari ati ons show a maxi m um in sum mer and a mini m um in winter [24-29]. Due to its long half-life (30.2 years) and the abundance in fission proces ses, cae sium-137 has been the most sig nif i cant fis sion prod uct and in di ca tor of anthropogenic pollu ti on in the envi ron m ent. In the 1990’s, con cen tra tions of 137Cs in ground level air, mainly origi nat ing from the Chernobyl nucle ar ac ci- dent in 1986, were the or der of µBq/m3, with maxima in summ er and win ter. The win ter maxim a were at trib - uted to resuspension of the Chernobyl fallout, with the strato spheric con tri bu tion less sig nif i cant [27, 30-32]. Prior to the nucle ar plant acci dent in Chernobyl, the 137Cs concen tra tions in mosses were in a wide range of val ues, somewhere as high as 20 kBq/kg d. w., with vari ati ons up to 80% that were more due to habi tat than to dif ference s in specie s [33]. In Fin land, the 137Cs con - centra tions in lichen were 2400 Bq/kg in the 1960s, around 200 Bq/kg in 1985, and reaching 25 kBq/kg in 1986/1987 [34]. In a long-term study (1987-1993), the Fig ure 1. Map of the Re public of Ser bia (with marked sam pling sites) 137Cs ecolog i cal half-life of 58.6 months and 10.9 months was found for moss and lichen, respec tively [35]. Af ter 2000, the distri bu tion of 137Cs in mosses and The sam pling area include d the Nati onal Park li chens over was uneven, from 10 Bq/kg d. w. to Djerdap, the towns of Kladovo, Negotin, and Zaje~ar, more than 1 kBq/kg d. w. [36-37]. the spas of Gamzigrad, , and Jo{anica, and A num ber of re cent studies have analy sed the mountai ns Ozren and Stara Planina (fig. 1). The radionuclides in moss and lichen in Serbia. The 137Cs Djerdap Na tional Park is locat ed in the north-east of ac tiv ities in soils and li chen in the moun tains of Serbia, on the bor der with Rom ania. It lies along the Serbia and Montenegro increa se with al ti tude (from right bank of the river and include s a narrow 1.2 kBq/kg d. w. to 18.6 kBq/kg) [38-40]. The acti vi - wooded mountai n region, with an alti tude of 50-800 ties of 137Cs in moss in the Belgrade city area (moun - meters a. s. l. Spa Sokobanja lies be tween the tain Avala) are signif i cant ly lower – up to 221 Bq/kg Carpathian and mountai ns ( and Ozren). [41], while in Southern Serbia, the acti v iti es reach Ozren is a well-known health re sort, rich in forest s and 578 Bq/kg [42]. Moss has also been used to esti mate veg e ta tion. Spa Jo{anica lies in the foot of the Bukovik depo si ti on of 7Be in Serbia [43-44]. Mountai n, at the alti tude of 200-500 meter s a. s. l. In this paper , the result s of long term deter mina - Geother mal wa ters of Sokobanja and Jo{anica spas are tion (1996-2010) of radionuclides in moss and lichen in con sid ered among highly ra dio ac tive wa ters in Ser bia. the re gion of East ern Ser bia are presented. The large Gamzigrad spa is in the vi cin ity of the Zaje~ar town num ber of data over a long time period pre sented in the (11 km), in the val ley of the Black Timok river, at an al - paper could be a signif i cant sta tisti cs base for model li ng ti tude of 160-180 m a. s. l. the distri buti on of radionuclides in the region.

MA TE RI ALS AND METHODS Ex per i men tal

The site Sam ples of moss and lichen were random ly col- lected in the region of Eastern Serbia from 1996-1998 The study was perform ed in the region of East- and 2000-2010. Up to 200 sam ples of mosses and 30 ern Ser bia (fig. 1). The cli mate in the area is con tinen - samples of lichen (Cladonia sp.) were collected over the tal, with cold winter s and hot sum mers. pe riod. Homolothecium sp., Hypnum Cupressiforme sp., A. ^u~ulovi}, et al.: Natu ral Radionuclides and 137Cs in Moss and Lichen ... 46 Nuclea r Technol ogy & Ra dia tion Pro tection: Year 2012, Vol. 27, No. 1, pp. 44-51 and Brachythecium sp. were most fre quently sam pled Table 1. Ac tiv i ties of nat ural radiounuclides in moss and moss species (ap prox im ately 30 samples per each spe - li chen, East ern Serbia cies). 40K 226Ra 232Th Period [Bq/kg d. w.] [Bq/kg d. w.][Bq/kg d. w.] The samples were cleaned, dried at room tem per a - Moss 281 ± 193 (69) 54 ± 29 (54) 19 ± 11 (58) ture and hom ogenise d, then soaked in par af fin in Marinelli 1996-1998 vessel s (1 L), and left for 30 days to reach the radio ac ti ve Lichen 209 ± 46 (22) 13 ± 4 (31) 11 ± 3 (27) equilib rium. Ac tiv ities of the radionuclides were de ter - 2000-2010 Moss 223 ± 84 (38) 13 ± 6 (46) 12 ± 6 (50) mined on an HPGe/ORTEC/Ametek de tector (rela tive ef - 2006-2010 Lichen 207 ± 51 (25) 12 ± 5 (42) 9 ± 2 (22) ficie ncy 34%, res olu ti on 1.65 keV at 1.33 MeV), and an HPGe de tec tor (Can berra, rel a tive ef fi ciency 25 %, res o - luti on of 1.95 keV at 1.33 MeV). the region [39, 42, 44], but somewhat lower than the ac- The total standard error of the method (includ ing tivi ti es re ported for moss sam pled in urban areas [41]. rel a tive er ror in geo met ric ef fi ciency es ti ma tion, photo This could be explai ned by the fact that in our study the peak counts es ti ma tion, sam ple vol ume de ter mi na tion, samplin g sites were not treated with fer tiliz ers, and, etc.) was es tim ated to about 20%. Spec tral anal ysis was there fore, the re sus pend ed con cen tra tions of nat u ral perform ed with the Gamma Vision 32 software package. radionuclides from soils, mainly 40K, were lower. The ac tiv i ties of 226Ra and 232Th were de ter mined by Higher vari ati ons in the content of nat ural radionuclides their decay products 214Bi (609.3 keV; 1120.3 keV, and in moss in 1996-1998 were due to larger sam pling area 1764.5 keV), 214Pb (352 keV), and 228Ac (338.4 keV; (mountai n Stara Planina include d), than later 911 keV, and 968.9 keV), respec tively. The acti vit y of (2000-2010), when the sam pling sites were more 137Cs was deter mined from its 661.6 keV line. The acti vi - closely grouped (Gamzigrad, Sokobanja, Djerdap, ties of 40K were de ter mined from its 1460 keV g-line. The Jo{anica) (fig. 1). The content of nat ural radionuclides ac tiv i ties of 7Ba were deter mined from its 477 keV g-line. was to some extent lower in lichen than in moss (tab. 1), The aver age counting time inter val was 60.000 s. Geo- but not signif i cant ly. It should be how ever noted that li- met ric cal i bra tion was per formed with dif fer ent ra dio ac - chen was col lected from higher points (trees) and the ef - tive ref er ence ma te ri als, in the sam pling ge om e try fect of resuspension from soil was less pronounced. (Marinelli 1 L): (1) Sil i cone Resin (Czech Metrological The fre quencie s of the 40K, 226Ra, and 232Th ac tiv i - Inst. CMI, Cert. No. 931-OL-191-01 Type MBSS 2 ties in moss in Eastern Serbia from 1996-2010 are given (241Am, 133Ba, 109Cd, 139Ce, 57Co, 60Co, 137Cs, 54Mn, in figs. 2 and 3. The acti vi ti es of 40K in moss were mainly 113 85 88 3 3 Sn, Sr, Y, 980.0 g, 0.98 ± 0,01 g/cm , 1000 ± 10 cm , within the range of 100-500 Bq/kg d. w., while the major - ref. date 1. 7. 2001); (2) Soil standard (Inst. Ra diolog i cal ity of the 226Ra and 232Th ac tiv i ties were spread within Protec tion, Belgrade: QAP 9803, 95.1 g, 29. 11. 2002); the range of 5-50 Bq/kg d. w. (figs. 2 and 3). Less than (3) Veg e ta tion (Inst. Ra dio log i cal Pro tec tion, Bel grade: 5% of 232Th ac tivi ti es was in the range of 50-100 Bq/kg QAP 9709, 23.12. 2002); (4) Sil icone raisin (CMI, Cert. d. w., while 226Ra acti vi ti es higher than 100 Bq/kg d. w. No. 9031-OL-032/05 Type MBSS 2 (241Am, 109Cd, were measured in less than 10% of the samples. 139Ce, 57Co, 60Co, 137Cs, 113Sn, 85Sr, 88Y, 441.0 g, 0.98 ± Based on our data of the mean acti vi ti es of natu - 0,01 g/cm3 , 45.0 ± 4.5 cm3, ref. date 15. 2. 2005); (5) Sil - ral radionuclides in soils sampled in the imme di ate vi - icone raisin (CMI, Cert. No. 9031-OL-159/08 Type cini ti es of the sam pling sites for moss and lichen (621 MBSS 2 (241Am, 133Ba, 109Cd, 139Ce, 57Co, 60Co, 137Cs, Bq/kg for 40K, 18 Bq/kg for 226Ra and 32 Bq/kg for 54Mn, 113Sn, 85Sr, 88Y, 980.0 g, 0.98 ± 0,01 g/cm3 , 1000 232Th), the soil-to-moss transfer factors were cal cu- ± 10 cm3, ref. date 1. 4. 2008). lated: 0.45 for 40K, 3 for 226Ra and 0.3 for 232Th. The result s corre spond with the data reporte d by other au- thors [22, 42]. RE SULTS AND DIS CUS SION

Nat ural radionuclides in moss and lichen in East ern Ser bia, 1996-2010

The ac tiv i ties of nat u ral radionuclides 40K, 226Ra, and 232Th in moss and lichen sam pled in Eastern Serbia, from 1996-1998 and 2000-2010 are present ed in tab.1. Since no signif i cant vari ati ons betwee n the sites were found, the re sults are given as “mean ± stan- dard devi a ti on” (Bq/kg dry weight), with coef ficie nts of vari ati on (%) in brackets . The acti vi ti es of natu ral radionuclides in moss in Eastern Serbia measured in 1996-1998 and in Fig ure 2. Frequency of 40K activ i ties [%] in moss in 2000-2010 were within the range of val ues re ported for East ern Ser bia, 1996-2010 A. ^u~ulovi}, et al.: Natu ral Radionuclides and 137Cs in Moss and Lichen ... Nuclea r Technol ogy & Ra dia tion Pro tection: Year 2012, Vol. 27, No. 1, pp. 44-51 47

226 232 Fig ure 3. Frequency of Ra and Th activ i ties [%] in Fig ure 6. Frequency of 137Cs activ i ties [%] in moss in moss in Eastern Ser bia, 1996-2010 East ern Ser bia, 1996-2010

The fre quen cies of the ac tiv i ties of nat u ral 137Cs in moss and lichen in East ern radionuclides in li chen in 1996-2010 are given in figs. Ser bia, 1996-2010 4 and 5. The frequency patter ns resem ble the pat terns seen in moss (figs. 2 and 3), with some dif ference s 137 40 The ac tiv i ties of Cs measured in moss in East- con cern ing K due to several very high ac tivi ti es of ern Serbia, from 1996-2010 are present ed in tab. 2. this radionuclide (above 500 Bq/kg d. w.) measured in The re sults are given as a range of val ues if the ac tiv i- moss. ties dif fer more than one-fold (i. e., vari a tions higher than 100%), and as ”mean ± stan dard de vi a tion” oth er - wise. The co ef fi cients of vari ations are given in brack - ets. Indi vid ual high values (max) that were not in- cluded in the calcu la ti ons are also given in brackets . LLD stands for lower limit of de tec tion. The dis tri bu tion of 137Cs ac tiv ities in moss con - firms the non-uniform spati al distri buti on of this radionuclide in the region. The wide range of val ues and highly pronounced local vari ati ons in our study com pared to some other authors over the same period [42-44], could be attri buted to the fact that the sam - pling sites were not ferti lized and subject ed to exten - sive anthropogenic ac tiv i ties. The tem po ral de crease in the 137Cs ac tiv ities in moss is well pro nounced, with Fig ure 4. Frequency of 40K activ i ties [%] in lichen in some lo cal ex cep tions. East ern Ser bia, 1996-2010 The fre quencie s of the 137Cs ac tiv ities in moss in Eastern Serbia, from 1996-2010, are present ed in fig. 6. Over the study pe riod (15 years), the acti vi ti es of 137Cs in moss were measured in the wide range of LLD-500 Bq/kg d. w., with less than 10% of sam ples with the ac- tivit y higher than 1000 Bq/kg d. w.

Ta ble 2. Ac tiv i ties of 137Cs in moss in East ern Ser bia, 1996-2010 Period Site 137Cs [Bq/kg d. w.] Stara Planina 16-384 1996-1998 Zaje~ar 33-748 Kladovo/Djerdap 166-9900 Zaje~ar/Gamzigrad/ 6-279 2000-2005 Sokobanja (max 2365) Kladovo/Djerdap LLD-745 Gamzigrad/Sokobanja/ 72 ± 45 (62.5%) Fig ure 5. Frequency of 226Ra and 232Th activ i ties [%] in li- 2006-2010 Jo{anica (max 1239) chen in Eastern Ser bia, 1996-2010 Kladovo/Djerdap LLD-223 (max 1131) A. ^u~ulovi}, et al.: Natu ral Radionuclides and 137Cs in Moss and Lichen ... 48 Nuclea r Technol ogy & Ra dia tion Pro tection: Year 2012, Vol. 27, No. 1, pp. 44-51

The ac tiv i ties of anthropogenic 137Cs in li chen Cupressiforme sp. (HC) and Brachythecium sp. (B) sam pled in Eastern Serbia in 1996-1998 and 2006-2010 are presented in tab. 4. The re sults are given as a range are presented in tab. 3. The re sults are given as ”mean ± of val ues if the acti vi ti es dif fer more than one-fold stan dard de vi a tion”, with the co ef fi cients of vari a tion in (i. e., vari ati ons higher than 100%), and as ”mean ± brack ets. Higher con tent of cae sium in lichen was mea- stan dard de vi a tion” oth er wise. The co ef fi cients of sured on sites with higher content of this radionuclide in vari ati ons are given in brackets . LLD stands for lower moss, but the varia ti ons of the 137Cs con cen tra tions in limit of de tec tion. li chen were gen er ally lower. The varia ti ons in the content of nat ural radionuclides in the three moss spe cies were in the Ta ble 3. Ac tiv i ties of 137Cs in li chen in East ern Ser bia, range 48-96% (tab. 4), but the dif ference s among the 1996-2010 spe cies were not sig nif i cant. The con cen tra tions of Period Site 137Cs [Bq/kg d. w.] 137Cs in the three moss spe cies showed high val ues 1996-1998 Eastern Serbia 233 ± 56 (24) prior to 2000, followed by a steep decrea se after wards. 2006 Sokobanja 14 ± 9 (64) To es ti mate the cor re la tion be tween the moss 2006-2008 Gamzigrad 164 ± 53 (32) spe cies for dif fer ent radionuclides, the lin ear Pearson 226 232 137 2008-2010 Djerdap 283 ± 86 (30) cor re la tion co ef fi cients for ( Ra, Th) and ( Cs, 40K) pairs were cal cu lated. High cor re lation (0.68) was ob tained be tween 226Ra and 232Th, as ex pected, The fre quencie s of the 137Cs ac tiv ity in li chen are and low (0.24) betwee n 137Cs and 40K. given in fig. 7. This fre quency patter n shows just few extre mes (above 400 Bq/kg d. w.). 7Be in moss and lichen in East ern Ser bia, 2006-2008

The ac tiv i ties of 7Be in moss and lichen sam pled in Eastern Serbia in 2006 and 2008 are present ed in tab. 5. The ac tiv ity of 7Be was cal cu lated on the date of the sam pling (in May 2006 and in June 2008). The ac- tiv ities are pre sented as “mean ± stan dard de vi a tion” from multi ple sam ples taken within each year (10-17 sam ples of moss per year and per site, and 6 sam ples of lichen per year and per site were ana lyzed), with co ef - ficie nts of varia ti on in brackets . The 7Be concen tra tions from two sam pling sites, both in moss and in li chen, were sig nif i cantly higher (20-60%) in 2008 than in 2006 (tab. 5). The Fig ure 7. Frequency of 137Cs activ i ties [%] in lichen in vari ations be tween the sites and within a year were East ern Ser bia, 2996-2010 also high (28-71%), mainly due to short half-life of 7Be and the dif ference s in micro cli mate and topol ogy of the sites. Since the 7Be ac tiv ities in air were not Nat u ral radionuclides and 137Cs in mea sured si mul ta neously, the ac tiv i ties in moss and moss spe cies: Homolothecium sp., li chen could not be com pared with the ac tivi ti es in Hypnum Cupressiforme sp., and air. Still, the 7Be concen tra tions in our study are com - Brachythecium sp. pa ra ble with its ac tiv ities in moss and lichen s in Southern Serbia [42]. Higher val ues (195-560 Bq/kg Con cen tra tions of nat u ral radionuclides and d. w.), with a strongly pronounced non-uni form ity in anthropogenic 137Cs in most fre quently sam pled spa tial dis tri bu tion, of the 7Be con cen tra tions in moss moss spe cies: Homolothecium sp. (H), Hypnum (Hypnum Cupressiforme) in Northern and Centra l

Ta ble 4. Ac tiv i ties of nat u ral radionuclides and 137Cs in Homolothecium sp. (H), Hypnum Cupressiforme sp. (HC), and Brachythecium sp. (B), in East ern Ser bia, 1996-2010 Species Period 40K [Bq/kg d. w.] 226Ra [Bq/kg d. w.] 232Th [Bq/kg d. w.] Period 137Cs [Bq/kg d. w.] 1997-1999 123-9990 H 246 ± 134 (55) 19 ± 18 (95) 15 ± 11 (73) 2000-2010 1.0-435 1997-1999 271-3100 HC 1996-2010 348 ± 190 (55) 25 ± 24 (96) 18 ± 11 (61) 2000-2010 15-438 1997-1999 LLD-1417 B 204 ± 97 (48) 15 ± 9 (60) 12 ± 7 (58) 2000-2010 LLD-146 A. ^u~ulovi}, et al.: Natu ral Radionuclides and 137Cs in Moss and Lichen ... Nuclea r Technol ogy & Ra dia tion Pro tection: Year 2012, Vol. 27, No. 1, pp. 44-51 49

7 Ta ble 5. Be in moss and li chen in East ern Ser bia, in 2006 AC KNOWL EDGE MENTS and 2008 7Be [Bq/kg d. w.] Sample type Site The pa per was re alized as a part of the pro ject 2006 2008 “New Tech nol o gies in the En vi ron men tal pro tec tion” Moss 61 ± 29 (48) 122 ± 45 (37) Sokobanja (No. 43009) and the project “Study ing clim ate change Lichen – – and its in flu ence on the en vi ron ment: im pacts, ad ap ta- Moss 66 ± 33 (50) 82 ± 23 (28) Gamzigrad tion and mit iga ti on” (No. 43007), fi nanced by the Lichen 41 ± 29 (71) 103 ± 43 (42) Min is try of Ed u ca tion and Sci ence of the Re pub lic of Serbia, within the framework of inte grat ed and inter - disci pli nary resea rch for the period of 2011-2014.

Serbia were re ported by [43]. Even higher ac tivi ti es of 7Be in moss, up to 920 Bq/kg, were shown by [44]. REF ER ENCES Assum ing that moss contai ns about one year of accu - mu lated 7Be from air [44], the 7Be con cen tra tion in [1] Gaare, E., The Chernobyl Ac ci dent: Can Li chen be 7 Used to Char ac ter ize a Radiocesium Con tam i nated moss could provide a reli able insight of the Be con - Range, Rangifer, 7 (1987), 2, pp. 46-50 centra tions in the ground level air of the area. [2] Papastefanou, C., Manolopoulou, M., Sawidis, T., Li - chens and Mosses: Bi o log i cal Mon i tors of Ra dio ac - tive Fall out from the Chernobyl Re ac tor Ac ci dent, J. CON CLU SIONS En vi ron. Radioact., 9 (1989), 3, pp. 199-207 [3] Papastefanou, C., Manolopoulou, M., Sawidis, T., Resi dence Time and Uptake Rates of 137Cs in Li chens The acti vi ti es of natu ral radionuclides in moss in and Mosses at Temper ate Lati tude (40° N), En vi ron. East ern Serbia measured in 1996-2010 were within Int., 18 (1992), 4, pp. 397-401 the range re ported for the region, but somewhat lower [4] Sloof, J. E., Wolterbeek, B. Th., Li chens as Biomonitors for Radiocaesium Fol lowing the than the ac tivi ti es re ported for moss sam pled in urban Chernobyl Ac ci dent, J. En vi ron. Radioact., 16 areas . Since the sam pling site in our study was not (1992), 3, pp. 229-242 treated with fertilizers, the re sus pend ed con cen tra - [5] Hofmann, W., et al., 137Cs Con cen tra tions in Li chen tions of nat ural radionuclides from soils, mainly 40K, be fore and af ter the Chernobyl Ac ci dent, Health were lower. Higher vari ati ons in the content of nat ural Phys., 64 (1993), 1, pp. 70-73 [6] Steinnes, E., Njastad, O., Use of Mosses and Li chens radionuclides in moss in 1996-1998 were due to the for Re gional Map ping of 137Cs Fall out from the fact that the sampling area was larger, and in cluded a Chernobyl Ac ci dent, J. En vi ron. Radioact., 21 mountai n region, than later (2000-2010), when the (1993), 1, pp. 65-73 sam pling sites were more closely grouped. The con - [7] Conti, M. E., Cecchetti, G., Bi o log i cal Mon i tor ing: Li - tent of nat ural radionuclides was to some extent less in chens as Bioindicators of air Pol lu tion Assess ment – a Re view, En vi ron. Pollut., 114 (2001), 3, pp. 471-492 li chen than in moss, but not signif i cant ly. It was proba - [8] Di Lella, L., et al., Li chen as Biomonitors of Ura nium bly due to the fact that lichen was col lected from and Other Trace Ele ments in an Area of Kosovo higher points (trees) and the ef fect of resuspension Heavily Shelled with De pleted Ura nium Rounds, from soil was less pronounced. The frequency patter ns Atmos. En vi ron., 37 (2003), 38, pp. 5445-449 of the nat u ral radionuclides ac tiv ities in li chen re sem- [9] Loppi, S., et al., Li chens as Biomonitors of Uranium in the Bal kan Area, En vi ron. Pollut., 125 (2003), 2, bled the pat terns seen in moss. pp. 277-280 The dis tri bu tion of the 137Cs ac tiv i ties in moss [10] Ruhling, A., Ty ler, G., Heavy Metal De po sition in Scan - con firmed the non-uni form spa tial dis tri bu tion of di na via, Wa ter Air Soil Pollut., 2 (1973), 4, pp. 445-455 this radionuclide in the region. The wide range of val - [11] Sumerling, T. J., The Use of Mosses as Indi ca tors of ues and highly pronounced local vari ati ons could be Airborne Radionuclides Near a Ma jor Nuclear In stal - la tion, Sci. To tal En vi ron., 35 (1984), 3, pp. 251-265 at trib uted to the fact that the samplin g sites were not [12] Steinnes, E., et al., At mo spheric De po si tion of Trace sub jected to ex ten sive anthropogenic ac tiv i ties. The El e ments in Nor way: Tem po ral and Spa tial Trend tem po ral de crease in the 137Cs ac tiv ities in moss was Studied by Moss Anal y sis, Water Air Soil Pollut., 74 well pronounced, with some local excep ti ons. Higher (1994), 1-2, pp. 121-140 content of cae sium in lichen was measured on sites [13] Ani~i}, M., et al., As sess ment of At mo spheric De po - sition of Heavy Metals and Other Ele ments in Bel- with higher content of this radionuclide in moss. grade Us ing the Moss Biomonitoring Tech nique and The dif ference s among the dif ferent moss spe - Neu tron Ac ti va tion Anal y sis, En vi ron. Monit. As - cies were not signif i cant . However , to sup port this sess., 129 (2007), 1-3, pp. 207-219 con clu sion, a fur ther anal y sis is needed. [14] Barandovski, L., et al., At mo spheric De po si tion of The varia ti ons in the 7Be con cen tra tions, both Trace El e ment Pol lut ants in Mac e do nia Stud ied by the Moss Biomonitoring Tech nique, En vi ron. 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Ana ^U^ULOVI], Dragana POPOVI], Rodoqub ^U^ULOVI], Jelane AJTI]

PRIRODNI RADIONUKLIDI I 137Cs U MAHOVINAMA I LI[AJEVIMA ISTO^NE SRBIJE

U radu su predstavqeni rezultati odre|ivawa radionuklida u mahovinama (Homolothecium sp., Hypnum Cupressiforme sp. i Brachythecium sp.) i li{aju (Cladonia sp.) koji su uzorkovani u regionu Isto~ne Srbije tokom 1996-2010 godine. Aktivnosti u mahovinama iznose 100-500 Bq/kg suve materije za 40K, i 5-50 Bq/kg suve materije za 226Ra i 232Th. Dobijeni su trans fer faktori “zemqi{te-mahovina”: 0.45 za 40K, 3 za 226Ra i 0.3 i 232Th. Prostorna distribucija aktivnosti 137Cs je izrazito neuniformna; mawe od 10% uzoraka, uglavnom onih pre 2000. godine, ima aktivnost ve}u od 1000 Bq/kg suve materije. Varijacije sadr`aja prirodnih radionuklida u mahovinama nisu zna~ajne. Frekvencione krive aktivnosti prirodnih radionuklida u li{aju sli~ne su onima u mahovinama, dok su aktivnosti izmerene u li{aju ne{to ni`e. Sredwa aktivnost 137Cs u li{aju mawa je od 400 Bq/kg suve materije. Sredwe aktivnosti 7Be u mahovinama i li{aju, koji su uzorkovani tokom 2006. i 2008. godine, iznose 41-122 Bq/kg suve materije, sa izra`enim varijacijama izme|u lokacija.

Kqu~ne re~i: mahovina, li{aj, radionuklidi, Isto~na Srbija