The radiological environment of Svalbard

Abstract

This paper presents a detailed survey of the radiological environment of the Svalbard area carried out from 2000 to 2002, in both the marine and terrestrial environment. In the marine environment in 2001, 99Tc activity concentrations in seawater were 0.13 to 0.36 Bq/m3, 5 fold higher than those in 1994, refl ecting the increase in 99Tc discharges from Sellafi eld in the mid 1990s. Cs-137 activity concentrations in seawater were 2.23 to 2.43 Bq/m3, ca. 10 fold lower than those in the 1980s, refl ecting the reduction in discharge of this radionuclide. Pu-238, 239+240Pu and 241Am activity concentrations in seawater were < 0.3 to 0.7 mBq/m3, 5.6 to 8.9 mBq/m3 and 0.6 to 2.4 mBq/m3 respectively, with activity ratios suggesting global fallout to be the dominant source. Tc-99 activity concentrations in brown algae were up to 18 fold higher than those in the 1980s with highest concentrations in Fucus distichus (25.7 to 58.7 Bq/kg d.w.). In the terrestrial environment, typical 137Cs activity concentrations in soil were between < 0.5 and 63 Bq/kg d.w. whilst activity concentrations of the natural radionuclides 238U (17 to 72 Bq/kg d.w.), 226Ra (21 to 70 Bq/kg d.w.), 232Th (10 to 57 Bq/kg d.w.) and 40K (115 to 818 Bq/kg d.w.) were similar to global averages. In terrestrial vegetation, 137Cs activity concentrations varied from 29 to 292 Bq/kg d.w. in mosses, 30 to 140 Bq/kg d.w. in lichen and 19 to 109 Bq/kg d.w. in fl owering plants. Elevated activity concentrations of 137Cs, 238U, 226Ra, Pu isotopes and 241Am were found in some matrices associated with seabird colonies.