Survey monitoring of environmental radioactivity in Seoul area

The following results were obtained through the environmental radiation monitoring in 2003 at the Seoul monitoring station : gamma exposure rate : 10.8 - 13.3 μR/h, mean gross beta activity in airborne dust : 4.31 ± 2.01 mBq/m3 (after 48 hours), mean gross beta activity in fallout dust : 11.5 ± 4.3 MBq/km2 - 30 days, meab gross beta activity in precipitation : 230 ± 246 mBq/L, mean gross beta activity in tap water : 69.3 ± 15.7 mBq/L. All the monitored variables remained in the corresponding normal ranges, which implies that there were no abnormal situations of environmental radiation in the Seoul district in 2003. Radioactivity contents in foodstuffs consumed in Seoul and northern part of Gyunggi district were analyzed for use in assessment of population doses via dietary intakes. Samples include 16 foodstuffs(peanut, walnut, pine seeds, chessnut, acorn, sesame, perilla seeds, oak mushroom, meadow mushroom, velvet foot, oyster mushroom, instant coffee, green tea leaves, ginseng tea, rice and Chinese cabbage). Two indicator samples, pine needle and mugwort, were also included. Relatively higher concentrations of l37Cs, a man-made nuclide, were found in coffee and oak mushroom(0.733 and 0.339 Bq/kg·fresh, respectively). A few hundreds Bq/kg·fresh of 40K were found in most of the foodstuffs with higher concentrations in coffee and green tea leaves (1300 and 579 Bq/kg·fresh, respectively)