i5 
Sb 125 are unchanged. The contamination of the sample with Cs 137, 
for example in the surface layer of 1 cm thickness had increased 
from 13.7 Bq/kg in January 1986 to 50.2 Bq/kg (see Table 7). Cs 134 
was not detectable in January. On the other hand, in August the sam- 
ple contained a specific activity of 18.6 Bq/kg Cs 134. 
In a suspended matter sample taken in August from the same sea area, 
there was the same nuclide composition as in the sediment surface 
sample (Table 7). However, the specific activity of the suspended 
matter sample, the majority of the nuclides, is about twice as high 
as in the sediment sample (Cs 137, Cs 134, Ru 103, Ru 106, Ag 110m). 
On the other hand, the specific activity of the nuclides Co 60 and 
Sb 125 not set free in the reactor accident differ by only about the 
factor 1.5 resp. 1.4. The activities of the natural nuclides differ 
anly insignificantly (not given in Table 7). Thereby the conclusion 
is permissible that in the sediments a "dilution” (e. g. owing to 
dioturbation) of the nuclides set free by Chernobyl had already ta- 
ken place. 
In December, a more extensive programme for the sampling of suspen- 
ded matter and sediments was carried out in the North Sea. The sus- 
pended matter was gained with the continuous flow centrifuge on 
board RV "Gauss”. The water volumes hereby put through, each ac- 
cording to the suspended matter content of the water samples, lay at 
between 1.5 and 18 m3. The suspended matter content varied between 
1.7 mg/l at position 54° 19' N, 07° 06' E and 132. 2 mg/l near 
Iwielenfleth in the lower Elbe on 18.12. (19.50 to 21.50 hrs.). The 
results of the Gamma-spectroscopic investigation are given in Table 
7. The specific acitivity of the suspended matter samples de-pended 
an the one hand upon the activity concentration of the water body, 
on the other hand however also upon the concentration of the 
suspended material in the water. All the samples within the sphere 
on influence of the Elbe have a specific activity (Alte Hever, Bü- 
sum), because the water in the Elbe in December still showed higher 
concentrations of Chernobyl Fallout radionuclides than the Weser or 
the Ems. This effect was particularly marked in the samples which 
were taken in the Elbe directly (Medemsand, Twielenfleth). There, 
the specific activity of Cs 137 even attained a value of 231 resp. 
350 Bq/kg. The difference found is to be traced back to the 
influence of the tides. Both samples were centrifuged during 
different phases of the outflowing water. 
The influence of the particle concentration upon the adsorbed speci- 
FEic activity can be particularly observed the two samples from Twie- 
lenfleth. With higher particle concentration, the adsorbed activity 
distributes itself over a greater mass, and thereby leads to lower 
specific activity. 
The influence of the water from the Elbe, with its higher activity, 
thereby permits its detection not only in water (Fig. 22) but also 
in the suspended matter samples from the German Bight. 
Ihe sediment samples from Stations 3 and 46, thus far, have been in-