~(129)I levels in soils from Ukraine and Slovenia in the last decade

摘要

~(129)I is important as an environmental tracer of the biogeochemical cycling of iodine and of the dissemination of nuclear pollution, because anthropogenic ~(129)I has been released from only few point sources and with its short mixing time its distribution therefore reveals the movement of ~(129)I in the environment. A radiochemical neutron activation analysis method was developed to measure the concentration of ~(129)I in soil samples. A procedure to pre-concentrate iodine from up to 150g of soil was developed and validated using IAEA standard reference material IAEA-375 (Chernobyl soil). The method was applied to determine ~(129)I/~(127)I isotopic ratios as well as ~(129)I and ~(127)I concentrations in soils from several locations in Ukraine collected in 2006, 1996, 1993 and 1989, and from Slovenia, collected at various places in 2009 and 2006. The ~(127)I concentrations in surface soils from Ukraine were in the range 2.3-23.1 μg g~(-1) and for ~(129)I (11.1-245.7)·10~(-8)μg g~(-1) dry matter with the highest value of 1.47- 10~(-3)μg g~(-1) found in a soil sample collected in Yaniv, Ukraine in July 1993. In soil samples from Slovenia ~(127)I concentrations ranged 0.73-130μg g~(-1) and ~(129)I (8.0-245.7) · 10~(-8)μg g~(-1). The ~(129)I/~(127)I isotopic ratios of surface soils from Ukraine were in the range of the order of 10~(-9)-10~(-5) and of 10~(-10)-10~(-8) for soils from Slovenia. The highest isotopic ratio 13.6·10~(-5) was found in a soil sample collected in Yaniv, Ukraine in July 1993.