Downward migration of radiocaesium in organic soils across a transect in Scotland

摘要

Following the accident at the Chernobyl nuclear power plant in 1986, radioactive materials including ~(137)Cs were distributed over large parts of the former Soviet Union and Europe. Due to the relatively long physical half-life of ~(137)Cs (30.1 y) measurable activity concentrations can still be observed in the natural environment. We have determined the depth distribution of ~(137)Cs from the testing of nuclear weapons in the atmosphere and Chernobyl, in eight highly-organic soils along an approximately east to west transect across the Central Highlands of Scotland. The ~(137)Cs activity concentrations in the soil profiles, corrected for radioactive decay to May 1986, were between 2.8 and 14.4 kBq m~(-2). There were differences in the pattern of distribution of ~(137)Cs in the soil profiles. The mean migration depth of ~(137)Cs in the soil profiles was 12.2 cm with a range between 8.2 and 17.4 cm. Quantitative mineralogical analysis of the ash obtained after heating the soil to 400℃ indicated that clay minerals alone did not have a prime role in controlling the migration of ~(137)Cs down the profile.