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, reflecting the increase in ⁹⁹Tc discharges from Sellafield 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, reflecting 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 flowering plants. Elevated activity concentrations of ¹³⁷Cs, ²³⁸U, ²²⁶Ra, Pu isotopes and ²⁴¹Am were found in some matrices associated with seabird colonies.