  We investigate the caesium concentrations in soils in mountain areas near
Gori nuclear power plant in Korea, focusing on the measurement limits to the
134Cs. In order to lower the minimum detectable amount (MDA) of activity for
the 134Cs, we have used the ammonium molybdophosphase (AMP) precipitation
method to get rid of the 40K existing in natural radioactivity, which reduces
the MDA activity about ten times smaller than those without the AMP
precipitation method. The MDA results for the 134Cs were found to be in the
range between 0.015 and 0.044 Bq/kg-dry weight. In order to diminish the
background, we also have measured a part of the soil samples in Yangyang, a
small town in the east coast of Korea. However, it turns out that in order to
detect the 134Cs in the samples the MDA should be reduced to the level of
mBq/kg-dry weight.
