The multivariable (cluster) analysis of all measured sediment samples (145) for
eight consecutive years depending on all measured nuclides shows that the type of
sediment is a basic factor for nuclide accumulation in sediments (Fig. 18.9). The
nuclide values for all sand sediments are combined in one cluster (from Albena to
Shabla max Eucledian distance is 2.5). The second cluster includes locations close
in geographical position and sediment type (slime) – Tuzla, Kavarna and Tzarevo,
while Bjala, Chernomoretz and Kaliakra are completely separate from the rest.
1991
1992
1993
1994
1995
1996
1998
1999
1991
1992
1993
1994
1995
1996
1998
1991
1992
1993
1994
1995
1996
1998
1999
0
10
20
30
40
50
T h-234
T h-232
R a-226
sa nd
silt
slim e
Fig. 18.7 Natural nuclide content (Bq/kg) in Black sea sediments in 1991–1999
0 2040 m 2010 m 115 m 130 m 109 m
76 m
56 m
20
40
60
80
100
120
140
160
Bq/kg
Cs-137
U-238
Ra-226
Th-232
Fig. 18.8 Mean nuclide content in deep-sea sediment samples
316
A. Strezov