Distribution of 90Sr in coastal seawater, sediments and organisms off two atomic power stations in Korea

We have measured 90Sr activities in the marine environment (seawater, sediments and organisms) off the two Korean atomic power stations at Gori and Weolseong. The marine sampling sites were chosen in the vicinity of the power stations to investigate the dispersion of any local 90Sr sources. The 90Sr activities in seawater ranged from 1.3 to 1.9 mBq/l (mean: 1.4, n = 16) and 0.9 to 1.5 mBq/l (mean: 1.3, n = 29) at the Gori and Weolseong sites, respectively. These activities are comparable with those reported for the remote open ocean, suggesting that the 90Sr at these sites originated primarily from global fallout, which occurred during the 1960s, rather than from any local sources. The 90Sr activities in marine sediments ranged from 116 to 1,277 mBq/kg (mean: 565, n = 12) and from 304 to 1,799 mBq/kg (mean 933, n = 6) at the Gori and Weolseong sites, respectively. The horizontal distribution of 90Sr in surface sediments appears to be affected by grain size as well as local sedimentation rate. The enrichment of 90Sr in fish (5.5 +/- 2.6 mBq/kg, n = 5) and shellfish (7.1 +/- 1.2 mBq/kg, n = 2) was much lower than that in seaweed (57 +/- 33 mBq/kg, n = 5).