The observation of atmospheric and sea water radioactivity in Japan for the year 1976

The observation was made by a network of 18 stations including one fixed ocean weather ship station (29 deg N, 135 deg E). The measurements of collected samples were made at the respective observation sites except those collected at the ship station, which underwent the measurement at Japan Meteorological Agency in Tokyo just after the return cruise ended. The analysis of the samples for detection of certain compositions was made by the analysis center at the Geochemical Laboratory of Meteorological Research Institute of JMA in Tokyo, to which the samples were sent regularly from each observation site. The gross beta radioactivity in precipitation, airborne dust and sea water, the deposition of 89Sr, 90Sr, and 137Cs, the natural background radioactivity, and the radioactivity in free atmosphere are reported. In addition, the observed data for the special observations about nuclear explosions are presented. (Yoshimori, M.)