Variation in the concentrations of iodine-129 (I-129, T-1/2 = 15.7 Myr), a low-level radioactive component of nuclear fuel waste, is documented in surface waters and depth profiles collected during 2001 along a transect from the Norwegian Coastal Current to the North Pole. The surface waters near the Norwegian coast are found to have 20 times higher I-129 concentration than the surface waters of the Arctic Ocean. The depth profiles of I-129 taken in the Arctic Ocean reveal a sharp decline in the concentration to a depth of about 300-500m followed by a weaker gradient extending down to the bottom. A twofold increase in the I-129 concentration is observed in the upper 1000m since 1996. Based on known estimates of marine transient time from the release sources (the nuclear reprocessing facilities at La Hague, France, and Sellafield, UK), a doubling in the I-129 inventory of the top 1000m of the Arctic Ocean is expected to occur between the years 2001 and 2006. As I-129 of polar mixed layer and Atlantic layer of the Arctic Ocean is ventilated by the East Greenland Current into the Nordic Seas and North Atlantic Ocean, further dispersal and increase of the isotope concentration in these regions will be encountered in the near future. (C) 2004 Elsevier Ltd. All rights reserved.

A numerical model simulation has been used to predict extent and variability in the anthropogenic I-129 pollution in the Arctic Ocean and Nordic Seas region over a period of 100 years. The source function of I-129 used in the model is represented by a well-known history of discharges from the Sellafield and La Hague nuclear reprocessing facilities. The simulations suggest a fast transport and large inventory of the anthropogenic I-129 in the Arctic and North Atlantic Oceans. In a fictitious case of abrupt stop of the discharges, a rapid decline of inventories is observed in all compartments except the North Atlantic Ocean, the deep Nordic Seas and the deep Arctic Ocean. Within 15 years after the stop of releases, the model prediction indicates that near-equilibrium conditions are reached in all compartments. (c) 2005 Elsevier Ltd. All rights reserved.

Polar oceans, though remote in location, are not immune to the accumulation of plastic debris. The present study, investigated for the first time, the abundance, distribution and composition of microplastics in sub-surface waters of the Arctic Central Basin. Microplastic sampling was carried out using the bow water system of icebreaker Oden (single depth: 8.5 m) and CTD rosette sampler (multiple depths: 8-4369 m). Potential microplastics were isolated and analysed using Fourier Transform Infrared Spectroscopy (FT-IR). Bow water sampling revealed that the median microplastic abundance in near surface waters of the Polar Mixed Layer (PML) was 0.7 particles m^-3. Regarding the vertical distribution of microplastics in the ACB, microplastic abundance (particles m^-3) in the different water masses was as follows: Polar Mixed Layer (0-375) > Deep and bottom waters (0-104) > Atlantic water (0-95) > Halocline i.e. Atlantic or Pacific (0-83).