Desorption of metals from Cetraria islandica (L.) Ach. Lichen using solutions simulating acid rain

Desorption of metals K, Al, Ca, Mg, Fe, Ba, Zn, Mn, Cu and Sr from Cetraria islandica (L.) with solutions whose composition was similar to that of acid rain, was investigated. Desorption of metals from the lichen was performed by five successive desorption processes. Solution mixtures containing H2SO4, HNO3 and H2SO4-HNO3 were used for desorption. Each solution had three different pH values: 4.61, 5.15 and 5.75, so that the desorptions were performed with nine different solutions successively five times, always using the same solution volume. The investigated metals can be divided into two groups. One group was comprised of K, Ca and Mg, which were desorbed in each of the five desorption processes at all pH values used. The second group included Al, Fe, Zn, Ba, Mn and Sr; these were not desorbed in each individual desorption and not at all pH values, whereas Cu was not desorbed at all under any circumstances. Using the logarithmic dependence of the metal content as a function of the desorption number, it was found that potassium builds two types of links and is connected with weaker links in lichen. Potassium is completely desorbed, 80% in the first desorption, and then gradually in the following desorptions. Other metals are linked with one weaker link (desorption 1-38%) and with one very strong link (desorption below the metal detection limit). [Projekat Ministarstva nauke Republike Srbije, br. III43009 i br. ON 172019

Natural Radionuclides and 137Cs in Mosses and Lichen in Eastern Serbia

The paper presents the results of ra dionuclides determination in mosses [Homolothedum sp., Hypnum Cupressiforme sp.. and Brachythecium sp.) and lichen {Cladonia sp.), sampled in the region of Eastern Serbia, during 1996-2010. Activities of 7Be, 40K, 226Ra, 232Th, and 137Cs were determined on an HPGe/ORTEC/Ametek detector (rela tive efficiency 34 %, resolution 1.65 keV at 1.33 MeV) and HPGe/Canberra detector (relative efficiency 25 %, re solution of 1.95 keV at 1.33 MeV) by standard gamma spectrometry. The average counting time was 60 000 s. The standard error of the method was 10 %. Spectral analysis was performed with the Gamma Vision 32 software package. The majority of the 40K activities mea sured in moss was within the range (100-500) Bq/kg dw (dry weight), while most of the 226Ra and 232Th activities of were in the range (5-50) Bq/kg dw. The calculated "soil-tomoss" transfer factors for 40K, 226Ra, and 232Th were 0.45, 3, and 0.3, respectively. Over the study period, the majority of the 137Cs activities in moss were in the range (0-500) Bq/kg dw, with less than 10 % of the samples with the activity higher than 1000 Bq/kg dw. The spatial distribution of the 137Cs activity was highly non-uni form over the region. The variations in the content of natural radionuclides among the three most sampled moss species were not significant. Linear Pearson correlation coefficient was 0.68 for 226Ra versus 232Th, and 0.24 for 137Cs versus 40K. The content of natural radionuclides in lichen was to some extent less than in moss, as lichen was collected from hi gher points (trees), and the effect of resuspension from soil was thus less pronounced. Still, the frequency pat tern of activities of natural radionu clides in lichen resembled the pattern seen in moss. The 137Cs activities in li chen were also less than in moss, with most of the concentrations below 300 Bq/kg dw. The mean activities of 7Be in moss and lichen sampled in Eastern Serbia in 2006 and 2008 were in the range (41- 122) Bq/kg dw, with variations up to 71 %.The 7Be concentrations were si gnificantly (20-60 %) higher in 2008 than in 2006. The pronounced ’Be va riations (28-71 %) between the sites and within a year were mainly a result of its short half-life and the differences in microclimate and topology of the sites

Elemental composition of moss and lichen species in eastern Serbia

Instrumental neutron activation analysis is used to determine a content of 47 elements (Na, Mg, Al, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni, Co, Cu, Zn, As, Se, Br, Rb, Sr, Zr, Mo, Ag, Cd, Sb, I, Ba, Cs, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Tm, Yb, Lu, Hf, Ta, W, Au, Hg, Th, and U) in mosses (Homolothecium sp., Hypnum cupressiforme Hedw., and Brachythecium mildeanum (Schimp.) Schimp.) and lichen (Cladonia fimbriata (L.) Fr.) collected in three locations in Eastern Serbia over years 2006-2010. Concentrations of six elements (Zr, Nd, Gd, Tm, Yb, and Lu) in mosses in Serbia are measured for the first time. For other elements, the obtained concentrations fall within the ranges reported for mosses and lichens in Europe, but no declining trend in concentrations of V, Cd, Cr, Zn, Ni, Fe, and Cu, that has been described in the literature, can be inferred from our results. Factor analysis shows that terrigenous and industrial components are the highest contributing factors to the elemental composition and that the most polluted measurement site is in the vicinity of a copper mining and smelting complex. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III43007: Climate changes and their influence on the environment: impacts, adaptation and mitigation and Grant no. III43009: New Technologies in the Environmental Protection

Influence of acid rain components on radiocesium-137 desorption from Cetraria islandica (L.) Ach. lichen

Desorption of 137Cs from Cetraria islandica (L.) Ach. lichen was performed by five consecutive desorptions with five identical solution volumes. Solutions of H2SO4, HNO3 and their mixtures, with pH 4.61, 5.15 and 5.75 were used for desorption. The desorbed amount of 137Cs (average value, all solutions used) from lichen, for a given pH value was 49.2% for pH 4.61; 47.0% for pH 5.15 and 47.6% for pH 5.75. The obtained values of the desorbed amount of 137Cs from lichen are in accordance with the data obtained in earlier work, when 46.2 % 137Cs was desorbed from lichen for pH 3.75, and 47.2% was desorbed for pH 2.87. A higher percentage of 59.8%, obtained for pH 2.00 indicates increased activity of H+ ions. The amount of desorbed 137Cs from lichen using solutions corresponding to acid rain cannot be lower than the stated values as they contain other substances besides the acid solutions used in this work