currents to the North Sea, from where a 
small proportion has entered the Baltic 
Sea. 
4. Authorised discharges of radioactivity 
into the sea occurring during the routine 
operation of nuclear installations in the 
Baltic Sea region (nuclear power plants 
and nuclear research reactors) have also 
contributed. 
This report describes work carried out by 
HELCOM’s project on the Monitoring of 
Radioactive Substances in the Baltic Sea 
(MORS-PRO) during the period 1999- 
2006. Chapter 2 describes the sources of 
man-made radioactivity in the Baltic Sea. 
Chapter 3 describes the levels of man 
made radionuclides in seawater, sediments 
and biota. Chapter 4 describes work on 
modelling and evaluations of the risks to man 
caused by radioactivity in the Baltic Sea. 
Chapter 5 compares the levels of man-made 
radionuclides in the Baltic Sea with levels in 
other sea regions. Chapter 6 summarises the 
project’s conclusions. Chapter 7 presents the 
consequent recommendations, and work on 
data quality is presented in the Appendix. 
References 
National Academy of Sciences (1971): 
Radioactivity in the marine environment 
(RIME), National Academy of Sciences, 
Washington DC, USA. 
UNSCEAR (2000): 
Sources and effects of ionizing radiation, 
United Nations Scientific Committee on the 
Effects of Atomic Radiation (UNSCEAR) 
Report to the General Assembly of the 
United Nations, New York.