Lycopodium cernuum and Funaria hygrometrica as deposition indicators for radionuclides and trace metals

Abstract

Levels of 210Pb, 210Po, 137Cs and some trace elements (Cu, Zn and Pb) in two most common mosses (Lycopodium cernuum and Funaria hygrometrica) distributed in the eastern Mediterranean sea region (Syrian coastal mountains series) have been determined. Radiochemical analysis has shown that these plants contain high levels of 210Pb, 210Po, 137Cs. The highest concentration of 210Pb, 210Po and 137Cs were found to be 1450, 1322 and 1140 Bq . kg-1 dry wt. in L. cernuum, respectively. F. hygrometrica was found to have higher values of 210Pb and 210Po concentrations and reached 2392 and 2119 Bq . kg-1 dry wt., respectively. Correlation coefficients for radionuclide levels in both plants versus their levels in soil have been determined: No correlation for 137Cs for both plants has been observed. This indicates that 137Cs in these plants is of atmospheric origin and the plants can be used as deposition indicators. In addition, a correlation with radionuclide levels was found only for 210Pb and 210Po in F. hygrometrica samples and was mainly related to 226Ra content in soil and the existing faults, which are the main source of these radionuclides. On the other hand, lead concentration in L. cernuum was found to be in the range of 5-86.6 ppm, while F. hygrometrica samples were found to contain around 58 ppm. Both plants seem to accumulate lead from the atmosphere where vehicle emissions are the main source of lead in the region. Comparable concentrations of Cu and Zn were found in all plant and soil samples.