North Sea oil and gas operations now contribute more man-made radioactivity to North European marine waters than the nuclear industry, according to the Marina II study, a European Commission (EC)-funded project undertaken by international experts to update data on the impact of radioactivity in the region's seas.
The study found that nuclear industry discharges to sea are back at the same level as the early 1950s, and that naturally occurring radioactive materials (NORM) now dominate doses to the European Union (EU) population from industrial discharges, both in terms of alpha activity and overall impact (collective dose).
Norway is the largest oil producer in the North Sea and is estimated to provide the greatest impact from current discharges. Norway is closely followed by the U.K., with Denmark and the Netherlands contributing relatively little. In 2000, according to the study, radioactive discharges from the non-nuclear industries were estimated to contribute more than 90% of the European population's total exposure from discharges into the marine region covered by the Ospar (Oslo &Paris) Convention.
Oil and gas operations contributed 35.3% and phosphates, 55.4%. This compared with the contribution to the collective dose rate from discharges of 3.8% from British Nuclear Fuels plc's (BNFL) Sellafield reprocessing complex, 1.7% from Cogema's La Hague facilities, 3.3% from weapons fallout, 0.2% from Chernobyl fallout, and 0.1% from nuclear power stations.
However, the overall impact of the discharges to the EU population can be gauged from the fact that, even at the discharges' peak, the collective dose rate was around a factor of 20 less than the annual collective dose from natural radioactivity in the marine environment. The Marina II results have been circulating within the expert community for some time and have been placed on the Internet and issued as a "Radiation Protection 132 Pre-Publication Copy," but the official report is not expected to be published for another month or so.
NORM is discharged as a result of phosphate fertilizer production, although such discharges have been reduced since the 1990s, and from the extraction of oil and gas from the continental shelf in the North Sea, mainly in the Norwegian and U.K sectors. NORM accumulates as scale inside pipework and valves at offshore oil and gas production platforms. It also gathers as sludge in separator tanks and other vessels. It is discharged in "produced water " and its radionuclides of radium--226 and Ra-228 and Pb-210 (lead) become available in concentrated form for consumption by marine biota.
The study was managed by U.K.-based NNC Ltd. under a contract with the EC's Directorate General for Environment. NNC worked with experts belonging to scientific institutions such as the U.K.'s National Radiological Protection Board, the Netherlands' Institute for Fishery Investigation and NRG nuclear consultancy, Denmark 's Riso National Laboratory, France's CEPN, Russia's SPA Typhoon, and Ireland's University College in Dublin. The team collaborated with Greenpeace, IAEA, the International Union of Radioecologists, Friends of the Earth, and the World Nuclear Association.
The study's results have been considered by the Ospar parties and resulted in a decision to recommend the reporting of discharges from the non-nuclear industries. The Ospar Convention for the Protection of the Marine Environment of the North East Atlantic was established in 1992. Its target is to ensure that radioactive discharges to the marine environment in the region are reduced to levels "close to zero" by 2020.
The Marina II data is expected to help establish a baseline against which progress in implementing the strategy can be evaluated. The Marina II study can be accessed at:
Source : Marina II Study