Radioactive contamination of the environmental samples in Hanoi in 1989

More than 30 environmental samples from soil, paddy, rice, fruits, vegetables and beans, sesame, tea, bananas, fishes at Hanoi markets in 1989 were analysed by gamma ray spectrometry with the low background system for studying natural and artificial radioactive elements. Among several samples from Hanoi in such kind as cultivated soils, tea, dried bamboo shoots, isotope Cs137 that used be generated from nuclear explosives was found with contents (30 - 1000) x 10-5 Bq/g; Cs137 contents in Japanese rice (0.4 - 3) x 10-5 Bq/g. Cs137 is radioactive so Cs137 contents in Vietnamese rice are 300 times higher than Cs137 contents in Japanese rice but they are hundred times lower than international standard. Among vegetables, fruits, shrimps, fishes in Hanoi markets, artificial isotopes were not found and natural isotopes were few. Even radioactive daughter and granddaughter in uranium series in potatoes were not found. In some samples K40 was also appeared, for example in cultivated soils (0.78 Bq/g), in dried bamboo shoots (0.73 Bq/g). (author). 2 refs., 3 figs