The distribution of dissolved thallium in the different water masses of the western sector of the Ross Sea (Antarctica) during the austral summer

• Published in: Microchemical Journal
• Main Authors: C. Turetta, BARBANTE, Carlo, CAPODAGLIO, Gabriele, GAMBARO, Andrea, CESCON, Paolo
• Other Authors: C., Turetta, Barbante, Carlo, Capodaglio, Gabriele, Gambaro, Andrea, Cescon, Paolo
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2010
• Subjects: Thallium; Ross Sea; Seawater; Reactive component; Non-conservative behaviour; Depth profile; Southern Ocean; Austral; Pacific; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/10278/31343; https://doi.org/10.1016/j.microc.2009.07.014

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.