Vertical distribution of 210Pb around Uraniferous coal-fired power plant in Western Turkey

Monitoring of 210Pb in soil, water, sediment and biological materials has been increasing in several pollution studies in recent years. The 210Pb in soils generated in situ by the decay of 226Ra is termed supported 210Pb and is in equilibrium with 226Ra. 210Pb activity in excess of the fraction which is derived from decay of the in situ 226Ra is called unsupported 210Pb. The amount of unsupported or atmospherically derived 210Pb in a soil can be calculated by measuring both the 210Pb and 226Ra activities and subtracting the 226Ra supported 210Pb component from the total 210Pb in the sample. We have determined the deposition rates of 210Pb from the atmosphere in Yatagan Region by measuring their inventories in core samples of cultivated and uncultivated soils.Yatagan is located in Western Turkey in a region where there are three CPPs operating with uraniferous coal. Energy production from coal is one of the major sources of increased natural radioactivity in the atmosphere. Soil samples were stored for a period of 2-3 half-lives (9 - 14 months) of 210Po (t1/2 =138 d) before analysis to allow build-up of 210Pb from 210Pb . The determination of the 210Po activity by alpha-counting provided an indirect measurement of the 210Pb activity. Measurements of 210Po were made through its 5.30 MeV alpha particle emission, using 208Po (5.11 MeV alpha emission, t1/2 = 2.9 yr) as the internal tracer. Measurements were made by silicon surface-barrier detector. The 210Pb activity concentrations in cultivated and uncultivated bulk soil cores varied between 83 Bq kg-1 - 22 Bq kg-1 and 250 Bq kg-1 - 55 Bq kg-1, respectively. (authors)