43 
Cs-137 : activity concentration (dissolved) 
Measd data: Model-Box=71, surface layer 
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 
Year 
Cs-137 : activity concentration (dissolved) 
Measd data: Model-Box=71, bottom layer 
- 120 
£ 
□ 69 Kattegat, deep 
© 100 
c 
o 
'JS 
? 
11 \ 
- 
<TJ 
~ 80 
y 
- 
Oi 
□ 
c 
t 
4 V 
i 
S 60 
;> 
i 
i) 
ii 
* 40 
K 
no 
MI 
i 
till 
à 20 
At/ 
•WWA 
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 
Year 
Cs-137 : activity concentration (dissolved) 
£ 
i 
r 
500 
450 
. □ 75 Belt Sea, surface 
120 
400 
E 
350 
ë loo 
£ 
O 
300 
| 80 - 
C 
250 
V 
o 
c 
200 
8 60 
& 
'5 
150 
S 40 
100 
50 
. 
no 
d 20 
Cs-137 : activity concentration (dissolved) 
Measd data: Model-Box=75 # bottom layer 
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 
Year 
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 
Year 
Cs-137 : activity concentration (dissolved) 
Measd data: Model-Box=81, surface layer 
Year 
Cs-137 : activity concentration (dissolved) 
Measd data: Model-Box=81, bottom layer 
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 
Year 
individual doses from man-made radionuclides 
peak in 1986 at 14 pSv. The corresponding 
dose from naturally occurring radioactivity in 
fish flesh is about 10 pSv. 
Future work will include assessments of 
the radiological risk to the environment 
from radioactive substances in the Baltic 
Sea. Assessments of the radiological risks 
to marine biota including mammals, fish, 
molluscs, crustaceans, algae and plankton 
may be based on work carried out in the 
ERICA Project (2004-2007) using a software 
tool developed for that purpose. 
Figure 2a: 
Comparison 
between 
calculated 
and observed 
concentrations 
of ,37 Cs 
in Baltic 
seawater for 
sub-regions 
69, 71,73, 75, 
77 and 81. 
Baltic Sea Environment Proceedings No. 117