WA6 Alaska North-Slope Environmental Monitoring
Room 18A/B, Level 4
8:00 AM - 12:00 PM, Wednesday, 12 November 2003
Chair: Boehm, Paul ,
(377) Riverine transport and dispersion of dissolved trace metals in the coastal Beaufort Sea.
Rember, R1, Trefry, J1, Trocine, R1, 1 Florida Institute of Technology, Melbourne, FL, USA
ABSTRACT- Samples for dissolved As, Ba, Cd, Cu, Fe, Pb and Zn were collected from the coastal Beaufort Sea and source rivers during 2000, 2001 and 2002. Concentrations of dissolved Cu, Cd, Fe, Pb and Zn in river water increased with increasing water discharge and correlated well (r > 0.82) with concentrations of dissolved organic carbon. Snow samples collected prior to peak flooding had concentrations of dissolved metals that were 10- to >100-fold lower than dissolved levels in the rivers during peak discharge. Results from this study show that greater than one-third of the annual inputs of dissolved Cu, Cd, Fe, Pb, Zn and DOC were carried to the coastal Beaufort Sea in 3 and 12 days, respectively, by the Kuparuk and Sagavanirktok rivers. The spring runoff was carried out to sea over and under the 2- to 3-m thick sea ice. Freshwater discharged below the ice was physically separated from the underlying seawater by a thin layer of frazil ice. Metal-rich river water was tracked under the ice for >20 km offshore from the Sagavanirktok River. Concentrations of dissolved metals below the turbid riverine discharge averaged about 20 pM for Pb, 5 nM for Cu and 90 nM for Ba and are typical of concentrations found in the coastal Beaufort Sea during the open water period in summer and fall. Concentrations of total dissolved Hg in the coastal seawater were low at about 3 pM relative to concentrations of 15 pM in the Sagavanirktok River during the spring floods.
Key words: spring floods, trace metals, Alaska, Beaufort Sea