Natural radionuclides in lichens, mosses and ferns in a thermal power plant and in an adjacent coal mine area in southern Brazil

Abstract

The radio-elements U,U, U,Th, Th andPo were characterized in lichens, mosses and ferns species sampled in an adjacent coal mine area at Figueira City, Paraná State, Brazil, due to their importance for the assessment of human exposure related to the natural radioactivity. The coal is geologically associated with a uranium deposit and has been used as a fossil fuel in a thermal power plant in the city. Samples were initially prepared at LABIDRO (Isotopes and Hydrochemistry Laboratory), UNESP, Rio Claro (SP), Brazil. Then, alpha-spectrometry after several radiochemical steps was used at the Applied Nuclear Physics Laboratories, University of Seville, Seville, Spain, for measuring the activity concentration of the radionuclides. It was Po the radionuclide that most bio-accumulates in the organisms, reaching the highest levels in mosses. The ferns species were less sensitive as bio-monitor than the mosses and lichens, considering polonium in relation to other radionuclides. Fruticose lichens exhibited lower polonium content than the foliose lichens sampled in the same site. Besides biological features, environmental characteristics also modify the radio-elements absorption by lichens and mosses like the type of vegetation covering these organisms, their substrate, the prevailing wind direction, elevation and climatic conditions. OnlyPo and U correlated in ferns and in soil and rock materials, being particulate emissions from the coal-fired power plant the most probable U-source in the region. Thus, the biomonitors used were able to detect atmospheric contamination by the radionuclides monitored.

Atmospheric Deposition of Radionuclides and Major and Trace Elements by Moss Biomonitoring Technique

“…CF= C sample / C reference (1) The enrichment degree of the metal can be classified as follows: no enrichment (CF≤1), minor enrichment (1<CF≤3), moderate enrichment (3<CF≤5), moderately severe enrichment (5<CF≤10), and severe enrichment (CF>10) [6,11]. Fig.…”

“…Therefore, moss biomonitoring was used as a complementary technique alongside classic instrumental methods in air pollution detection and control. Also, mosses have been used as bioindicators for terrestrial long-lived radionuclides ( 40 K, 238 U, and 232 Th) and artificial radionuclides ( 137 Cs, 90 Sr, and 239+240 Pu) in the environment [1][2][3][4][5].Rapid industrialization in cities and the contributory relationships with the original pollution sources can cause serious environmental problems within cities [6][7][8][9]. Istanbul is the most crowded city in Turkey and the fifth most crowded in the world.…”

“…Therefore, moss biomonitoring was used as a complementary technique alongside classic instrumental methods in air pollution detection and control. Also, mosses have been used as bioindicators for terrestrial long-lived radionuclides ( 40 K, 238 U, and 232 Th) and artificial radionuclides ( 137 Cs, 90 Sr, and 239+240 Pu) in the environment [1][2][3][4][5].…”

Radiocaesium accumulation capacity of epiphytic lichens and adjacent barks collected at the perimeter boundary site of the Fukushima Dai-ichi Nuclear Power Station

“…Lichens are symbiotic organism composed of fungi and algae that are well known to incorporate and store a variety of radionuclides derived from both natural origins, like U-238, Ra-226, Th-232 etc. in mine areas [1,2], and artificial origins such as atmospheric nuclear weapon tests and nuclear power plant accidents [3][4][5][6][7]. Lichens are recognized as useful biomonitoring tools because of having the following features: (i) they are widely distributed in terrestrial ecosystems and found on various substrata such as rock, tree, soil, artificial man-made structures, and so on, (ⅱ) they can accumulate metals including radionuclides directly absorbing from air into the body, due to their lack of root system and protective outer cuticle, (ⅲ) they have high accumulation capacities of pollutants on the large surface areas of thalli, and (ⅳ) they have longevity due to their slow metabolic activity and slow growth rate throughout the year [8][9][10].…”

Tobacco plant as possible biomonitoring tool of red mud dust fallout and increased natural radioactivity

“…Reviews and reports indicate the use of mosses (Ares et al, 2012) for lead and 210Pb (Galhardi et al, 2017;Kosior et al, 2017) as NORM retention indicators in ecosystems (Reszka and Wołoszyn, 2007;Shotyk et al, 2015). Grodzinskaya recently published an extensive overview of tree NORM and heavy metal levels in city parks and streets in Kyiv, Ukraine (Grodzinskaya et al, 2019).…”