Sonderen JF van ; Drost RMS ; Graber MH ; Ockhuizen
A ; Koolwijk AC
32 p
in Dutch
1991
Toon Nederlands
English Abstract this report contains the results for 1990 of
measurements of radioactivity in the rivers Meuse, Rhine, Roer, in the
Westerscheldt, in the Channel of Sas van Gent to Terneuzen, and in het North
Sea along the Dutch coast. The Sr-90-content in Meuse, Rhine and Roer
varies between 2.4 Bq/m3 and 6.9 Bq/m3. In the Westerscheldt higher
contents are found (between 9 Bq/m3 and 22 Bq/m3. The Sr-90-content of
seawater varies between 7 Bq/m3 and 12 Bq/m3. Sr-89 was not found. As in
previous ywars, the Ra-226- contents found in samples of the Roer (between
11 Bq/m3 and 14 Bq/m3) are higher than the ones measured in samples of the
Meuse and of the Rhine (between 2.0 Bq/m3 and 6.1 Bq/m3). The
Ra-226-content of the Westerscheldt varies between 6 Bq/m3 and 38 Bq/m3.
The Po-210 and Pb-210-contents of the Meuse, Rhine and Roer are almost the
same. The Po-210 and Pb-210-contents of the Westerscheldt are considerably
higher than the contents of the rivers mentioned above: the yearly average
of the Po-210-content is 26.3 Bq/m3 and of the Pb-210-content 24.2 Bq/m3.
The Po-210 and Pb-210-contents of the Westerscheldt have increased during
the last four years. Samples of suspended matter from the Meuse, Rhine,
Roer, Westerscheldt and the Channel of Sas van Gent to Terneuzen were
examined by means of gammaspectrometry. Natural as well as artificial
radionuclides are found. The H-3-contents in the North Sea (between 1100
Bq/m3 and 3500 Bq/m3) are generally the same as in 1989. The
Cs-137-contents measured vary between less than the detection limit (2
Bq/m3) and 25 Bq/m3.