#7 
Gamma-radiation. Higher contaminated samples were thereupon investi- 
gated Gamma-spectroscopically for their nuclide composition. Owing 
to dilution and mixing processes with deeper water layers in the 
sea, the radioactivity concentration decreased rapidly. That is why 
a few days after the input, a gamma-spectroscopic determination of 
the untreated samples was no longer possible. 
The rapid determination of the composition of the nuclide mixture of 
Gamma-emitting isotopes provided no difficulties. The determination 
of the nuclide portion of the Transuranics - Plutonium, Americium, 
and Curium - required a longer analysis time. The determination of 
TIritium in a strongly contaminated sample of the first rain shower 
in Hamburg after the accident in Chernobyl revealed no significant 
increase compared with the normal values. For that reason, for the 
time being, further Tritium measurements of seawater samples were 
discontinued. Application of the routine determination of the nucli- 
de Strontium 90 was not possible in the case of this Fallout, owing 
to the fact that several other short-life nuclides in the radioche- 
mical separation process were not separated completely. Therefore, 
it was necessary to change the analysis method correspondingly imme- 
diately. 
In general, it has been ascertained that the nuclide mixture to be 
monitored after the accident had changed from long-lived - with good 
aqueous solubility —- to partly very short-lived nuclides with other 
solubility properties. 
In order to ascertain the nuclide composition of the input into the 
sea, aerosol investigations were carried out in Hamburg-Sülldorf. 
The nuclide pattern was ascertained by Gamma-spectroscopy. Hereby, 
the relative activity concentration of the most important nuclides, 
in relation to Caesium 137 on 5th / 6th May, are shown in the fol- 
lowing Table: 
Nuclide 
Cs 137 
Cs 134 
Ru 103 
Ba/La 140 
J 131 
Te 132/33 132 
Rel. activity 
1.00 
0.52 
2.00 
0.67 
6.00 
2,20 
Half-life 
10 958 
754.2 
39.27 
12.75 
8.02 
3.20 
days 
(30 years) 
The following further nuclides were then later detectable in lesser 
concentrations in different samples from the region of the sea: 
Nuclide 
5r 90 
Pu 239 
Pu 238 
Am 241 
Np 239 
Cm 242 
ZA 
Hal£-1ife 
28.92 years 
400 " 
86.4 " 
45R 
2.35 da 
163