Radiation dose rate in the air and the contents of radionuclides in environmental samples in the coastal regions of the Okhotsk Sea

We investigated the radiation dose rate in the air and the contents of radionuclides in the environmental samples (soil, raw grass, feed, raw cow's milk) in the coastal regions of the Okhotsk Sea from 2000 to 2002. The following results were obtained concerning the local feature of environmental radioactivity levels in the coastal regions of the Okhotsk Sea. 1. The radiation dose rate in the air above the grassland was 30-60 nGy/h which was two times higher than that in eastern Hokkaido. 2. 137Cs accumulated in soils (depth, 0-30 cm) of the grassland were calculated to be more than 82% of the total 137Cs accumulated in soils. 3. 137Cs and 90Sr contents in raw cow's milk were at low levels, because 137Cs and 90Sr contents in raw grass were low. Especially, 137Cs contents in raw cow's milk were about 1 order of magnitude lower than that in eastern Hokkaido. (author)