Tracing depositional consequences of environmental radionuclides (137Cs and 210Pb) in Slovenian forest soils

Abstract

Depth distribution profiles of environmental radionuclides (137Cs and 210Pb) have been investigated in soil to elucidate the underlying environment of semi-natural temperate deciduous and/or coniferous forest soils in Slovenia (Žirovski vrh, Idrija, Kočevski Rog, Pohorie, Gorišnica and Rakitna). Surface enrichment of both nuclides was observed at all the sites investigated in this study, suggesting that the soils had undergone little natural or anthropogenic disturbance for at least the last several decades. Apparent annual burial rates of 137Cs (0.1–0.2 cm y−−1) were estimated to be about 1.3 times higher than those of 210Pb at individual sites of different lithology, which suggests strong affinity of 210Pb to soil organic matter. Variability of the vertical distribution profiles of these nuclides depends not only on “in situ” pedology but also on geographical and meteorological conditions, especially precipitation and wind direction.

Variability of 40K isotopic composition in forest soils under different environmental conditions

“…158 Table 1 shows the results of some soil properties (density, 159 humidity, pH and soil organic matter) in Tomakomai and 160 in Slovenian forest sites [15,16]. Details of the experi-161 mental procedures were described previously [12].…”

“…221 Results in the carbonaceous soil in Rakitna (P6) showed 222 high and variable 40 K/K values with two peaks appearing 223 about at 4-6 and 20-22 cm in depth, which may reflect 224 different soil properties such as density and pH [15]. 225 In Tomakomai two types of soil horizon with different 226 40 K/K ratio appeared on the profile, as shown in Fig.…”

Soil radon (222Rn) monitoring in a forest site in Fukushima, Japan

“…Two and a half years after the accident, activity concentration of short-lived 134 Cs (T 1/2 =2.07 y) was about a half of that of 137 Cs (T 1/2 =30.17 y). Activity concentration of radiocesium present within the surface portion of soil (depth of <5 cm) decreased exponentially with soil depth, thus suggesting no natural and/or anthropogenic intervention since then (Fujiyoshi et al, 2011).…”

“…Two and a half years after the accident, activity concentration of short-lived 134 Cs (T 1/2 =2.07 y) was about a half of that of 137 Cs (T 1/2 =30.17 y). Activity concentration of radiocesium present within the surface portion of soil (depth of <5 cm) decreased exponentially with soil depth, thus suggesting no natural and/or anthropogenic intervention since then (Fujiyoshi et al, 2011).Soil radon ( 222 Rn) monitoring started in August 2013 on the observation site of known basic information on geology, climate and soil properties, already described in the previous section (Material and methods). Figure 3 shows time series changes in 222 Rn activity concentration in soil air at different soil depths (0.3, 0.6, and 1.0 m) at the observation point, together with atmospheric pressure from August 21 to December 6, 2013.…”

Estimating emission source of lead using 210Pb specific activity (210Pb/Pb) and zinc as tracers in Slovenian forest soils

“…The present authors investigated depth distribution profiles of 210 Pb (and 137 Cs) to trace depositional consequences of airborne Pb (and fallout 137 Cs due to the Chernobyl accident) in several Slovenian forest sites [5]. They estimated apparent burial rates (Bq year -1 ) and inventories (Bq m -2 ) to estimate downward migration of these nuclides with decomposing organic matter in soil.…”