ANTHROPOGENIC AIRBORNE DEPOSITIONS OF Po-210, Pb-210 AND Po-210/Pb-210 IN THE MOSSES AND SURFACE SOILS AT THE VICINITY OF A COAL-FIRED POWER

Anthropogenic airborne depositions of 210Po, 210Pb and 210Po/210Pb in the mosses and surface soils collected at the vicinity of a coal-fired power plant were studied. The purpose of the study was to determine activity concentrations of 210Po, 210Pb and 210Po/210Pb for assessing their variation accumulation in the mosses and surface soils collected at the vicinity of a coal-fired power plant. Other purposes were to determine their concentration factor (CF) in relation to track the potential source of those radionuclides and to identify most suitable moss species as a biological indicator for atmospheric deposition contaminants. In this study, different species of moss Leucobryum aduncum, Campylopus serratus, Syrrhopodon ciliates and Vesicularia montagnei were collected in May 2011 at the area around 15 km radius from Tanjung Bin coal-fired power plant located in Pontian, Johor. The activity concentrations of 210Po, 210Pb and 210Po/210Pb in mosses were in the range of 76.81 ± 4.94 – 251.33 ± 16.33 Bq/kg dry wt., 54.37 ± 3.38 – 164.63 ± 11.64 Bq/kg dry wt. and  1.10 – 2.00, respectively. Meanwhile the ranges for those radionuclides in the surface soil were 33.53 ± 2.10 – 179.67 ± 12.15 Bq/kg dry wt., 20.55 ± 1.33 – 106.62 ± 6.64 Bq/kg dry wt. and 1.61 – 2.44, respectively.  Corresponding high ability of Leucobryum aduncum to accumulate more 210Po and 210Pb, wide geographical distribution, most abundant and high CF, therefore, the findings can be concluded this species was the most suitable as a biological indicator for atmospheric deposition contaminants such as 210Po and 210Pb. Furthermore, it is clear the accumulation of 210Po and 210Pb in mosses might be supplied from various sources of atmospheric deposition such as coal-fired power plant operation, industrial, agriculture and fertilizer activities, burned fuel fossil and forest; and other potential sources. Meanwhile, the main source of 210Po and 210Pb in surface soil is supplied from the in situ decay of radon and radium.