Vertical profiles for total dissolved thallium were obtained at five sites in the western sector of the Ross Sea (Southern Ocean), Antarctica. Thallium is estimated to have a natural mean seawater concentration between 50 and 65 pmol L−1with higher values in theNorth Pacific (65±5 pmol L−1) and lower inthe Bay of Biscay and Irish Sea (49±3 pmol L−1). Our samples show a concentration varying from22 to 55 pmol L−1 with amean value of 46 pmol L−1, depending on depth, dissolved oxygen, salinity and local topographic characteristics. The analyses were performed using an ICP-SFMS that has enabled us to obtain reliable Tl concentrationmeasurements with a relative standard deviation of better than 2.5% and a detection limit, calculated as three times the standard deviation of the “blank signal” of 0.69pmol L−1 (1.60 pmol L−1, obtained analysing four blank solutions (n=5) prepared with the same water and acid used for the dilution/acidification steps). Thallium appears to have a nearly conservative distribution in seawater as highlighted also from the comparison with the profiles of two seawater conservative elements:molybdenumand uranium;however it also highlights the presence of a reactive component of thallium, which is more influenced by the presence of particulate matter, oxygen content and fluorescence.
|Titolo:||The distribution of dissolved thallium in the different water masses of the western sector of the Ross Sea (Antarctica) during the austral summer|
|Data di pubblicazione:||2010|
|Appare nelle tipologie:||2.1 Articolo su rivista |
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