Leijen CATM ; Drost RMS ; Ockhuizen A ; Koolwijk
AC
29 p
in Dutch
1991
Toon Nederlands
English Abstract This report presents the results of measurements of
radionuclides deposited in the Netherlands (Bilthoven) in 1990.
Measurements were carried out to determine the weekly activities of
gamma-emitters, of H-3 (on a weekly basis) and of Pb-210 and Po-210 (on a
monthly basis). The gross alpha, gross beta and gross gamma-activity were
also determined on a weekly basis. The yearly average concentration of H-3
in rain was 1.8 +- 0.2 kBq/m3, lower than in 1989. The total deposition
of H-3 was 1360 +- 120 Bq/m2, which is lower than in the period 1985 - 1989.
The total deposition of Be-7 was 810 +- 36 Bq/m2, slightly higher than in
1989. The weekly deposition of Cs-134 was always below the detection limit
of 0.05 Bq/m2. The total activity of Cs-137 in deposition was less than
5.5 Bq/m2. The total depositions of the natural radionuclides Pb-210 and
Po-210 were 85 +- 4 Bq/m2 respectively 16 +- 2 Bq/m2. These values are
below those found in 1989. In 1990 the gross alpha-activity in deposition
was 68 +- 1 Bq/m2, which is slightly higher than in previous years. The
gross beta-activity in deposition was 121 +- 4 Bq/m2, which is also higher
than the value found in 1989. The gross gamma-activity was 109 +- 4 Bq/m2.
This was lower than in the years 1985 - 1989.
