dc.description.abstract | Activity concentrations of cosmogenic beryllium-7, terragenic lead-210 and artificial caesium-137
are closely observed within environmental radioactivity monitoring programmes in Serbia and
Slovenia. In this study, we compare the temporal evolution and seasonal cycles of the radionuclides
recorded over 1991–2015 in three locations: Belgrade (44.88333 °N; 20.583333 °E; 95 m a.s.l.), the
capital of the Republic of Serbia; Krško (45.950414 °N; 15.512261 °E; 204 m a.s.l.), a town in eastern
Slovenia, located ~400 km west of Belgrade; and Ljubljana (46.042356 °N; 14.487494 °E;
292 m a.s.l.), the capital of the Republic of Slovenia, located ~500 km west of Belgrade. The latitudes
of these three sites differ only slightly, approximately by 1°.
The similarities between the data sets are evident from their measurement ranges and long-term
means. For example, the recorded beryllium-7 activity concentrations fall within the ranges reported
for different locations in Europe. In the lead-210 series, the observed values are similar to the activity
concentrations reported for some neighbouring regions, but around twofold higher than in locations
that are under a significant maritime influence, thus removed from this radionuclide’s source. The
activity concentrations of caesium-137 at all the sites are of the same order of magnitude and agree
with the post-Chernobyl picture of the fall-out in Europe.
However, there are some noticeable differences in the seasonal cycles of these radionuclides at
the investigated sites. For example, even though the beryllium-7 seasonal cycles in all the sites exhibit
a spring/summer maximum and a winter minimum, the timing of the maximum recorded at the
Slovenian sites is agreement with other Western European sites of similar latitude in contrast to the
Belgrade site that shows an earlier occurrence of the maximum, more in line with European locations
further north.
A possible explanation for the observed dissimilarities could lie in the differences of the
meteorological patterns in the investigated sites. According to Köppen-Geiger climate classification,
Krško and Ljubljana have Warm temperate fully humid climate with warm summers (Cfb), while
Belgrade is characterised by Warm temperate fully humid climate with hot summers (Cfa). Belgrade
is located deeper in the continental landmass, and its climate has more of midlatitude continental
characteristics, in terms of higher summer temperature, more pronounced seasonal temperature
amplitude, and lower precipitation, especially during summer months. These differences in climate
affect the transport and removal of the radionuclides from the atmosphere and could lead to the
observed dissimilarities. Still, a detailed analysis of the radionuclides’ time series and their relation to
the time series of the meteorological parameters is needed to better understand their interconnexion. | sr |