Within an extensive multinational and multidisciplinary project carried out in Dohana National Park (Spain) to investigate its preservation and regeneration, the filling velocity of the salt marshes has been evaluated through the calculation of their average sediment accumulation rates.Pu239+240 and Cs-137 from weapons testing fallout and total Pb-210 distribution profiles and inventories have been determined in some of the most characteristic zones of the park, namely, the ponds 2 (or "lucios") and the waterjets (or "cahos"). Plutonium inventories range from 16 to 101 Bq m(-2), Cs-137 values fluctuate between 514 and 3758 Bq m(-2) and unsupported Pb-210 values comprise between 124 and 9398 Bq m(-2). Average sedimentation rates range from 3 to 5 mm y(-1) (1952-2002). These data are higher than those obtained by carbon dating for the period 6500 AD-present, estimated as 1.5-2 mm y(-1), suggesting an increase in the accumulation of sediments and the alteration of the park's hydrodynamics caused by the re-channeling of the major rivers feeding the salt marshes. (c) 2006 Elsevier Ltd. All rights reserved.

Continental margins are important areas to be considered when studying the distributions and depositions of pollutants, both conventional and radioactive. Coastal sediments accumulate most of those contaminants which can be introduced following atmospheric and/or fluvial pathways. Moreover, their residence times within the water column are usually shortened due to their affinity to associate with the downward falling particulate matter, more abundant at shallower depths. In this paper, the distribution profiles and inventories of plutonium, americium and cesium are detailed, providing useful information about recent sedimentation phenomena such as sediment mixing, slumping processes and bioturbation. Unsupported 210Pb data are used as reliable indicators of enhanced/reduced deposition events. Also, the calculated inventories have enabled the estimation of the radiological contribution of the Spanish Mediterranean margin to the total radioactivity deposited onto the Mediterranean sea floor.

The activity concentrations and fluxes of natural (Pb-210, Po-210) and anthropogenic (Pu-239,Pu-240 Cs-137) radionuclides have been determined in the different water masses crossing the Strait of Gibraltar. New data have been gathered during four multidisciplinary and multinational sampling campaigns, performed between 1997 and 1999 within the framework of the CANIGO-FLUGIST Project.Mean activity concentrations of Po-210 (1.53 +/- 0.34 Bq m(-3), n = 30) and Pb-210 (1.16 +/- 0.50 Bq m(-3), n = 31) in the Atlantic water entering the Mediterranean basin are about double those measured in the Mediterranean outflow, namely 0.84 +/- 0.34 Bq m(-3) (n = 22) for Po-210 and 0.66 +/- 0.34 Bq m(-3) (n = 22) for Pb-210. The opposite trend is observed for Pu-239,Pu-240 with average concentrations of 9.9 +/- 3.0 mBq m(-3) (n = 29) in the incoming Atlantic flow and 22.0 +/- 3.0 mBq m(-3) (n = 22) in the outpouring Mediterranean water. In the case of Cs-137, the same concentrations were quantified in the waters moving inwards (2.52 +/- 0.28 Bq m(-3), n = 27) and outwards (2.14 +/- 0.52 Bq m(-3), n = 21) from the Mediterranean Sea.On this basis, the Mediterranean basin experiences a net annual input flux of 14 TBq of Pb-210 and 19 TBq of Po-210, and a net annual loss of 0.34 TBq of Pu-239,Pu-240, while-at present-Cs-137 input and output fluxes appear to be balanced. (C) 2002 Elsevier Science Ltd. All rights reserved.