Four decades of radioecological research on the Danube river: a reliable basis for protecting the freshwater resources of central Europe of tomorrow

INTRODUCTION Since the beginning of the atmospheric nuclear weapon test period in the end of the fifties the radioactive contamination of the environment was monitored and evaluated by scientists of national health authorities in regard to minimise the health risks of the population. The Danube with a total length of 2857 km and a drainage area of about 817 000 km2 in central Europe (Fig. 1) became also an important ecological target for monitoring and evaluation of man-made radioactivity. As the second biggest river in Europe after the Volga the Danube is used as drinking water source, for irrigation purpose, for fishery, for sport and recreation, as water supply for industry, and for transportation. So the Danube acts as live resource for nearly 70 million people in Europe.