Increased concentrations of dissolved trace metals and organic carbon during snowmelt in rivers of the Alaskan Arctic

Arctic rivers typically transport more than half of their annual amounts of water and suspended sediments during spring floods. In this study, the Sagavanirktok, Kuparuk and Colville rivers in the Alaskan Arctic were sampled during the spring floods of 2001 to determine levels of total suspended solids (TSS) and dissolved and particulate metals and organic carbon. Concentrations of dissolved organic carbon (DOC) increased from 167 to 742 μmol/L during peak discharge in the Sagavanirktok River, at about the same time that river flow increased to maximum levels. Concentrations of dissolved Cu, Pb, Zn and Fe in the Sagavanirktok River followed trends observed for DOC with 3- to 25-fold higher levels at peak flow than during off-peak discharge. Similar patterns were found for the Kuparuk and Colville rivers, where average concentrations of dissolved trace metals and DOC were even higher. These observations are linked to a large pulse of DOC and dissolved metals incorporated into snowmelt from thawing ponds and upper soil layers. In contrast with Cu, Fe, Pb and Zn, concentrations of dissolved Ba did not increase in response to increased discharge of water, TSS and DOC. Concentrations of particulate Cu, Fe, Pb and Zn were more uniform than observed for their respective dissolved species and correlated well with the Al content of the suspended particles. However, concentrations of particulate Al were poorly correlated with particulate organic carbon. Results from this study show that >80% of the suspended sediment and more than one-third of the annual inputs of dissolved Cu, Fe, Pb, Zn and DOC were carried to the coastal Beaufort Sea in 3 and 12 d, respectively, by the Kuparuk and Sagavanirktok rivers.

[1]  K. Bencala,et al.  Response characteristics of DOC flushing in an alpine catchment , 1997 .

[2]  G. Cauwet,et al.  The biogeochemistry of Lena River: organic carbon and nutrients distribution , 1996 .

[3]  D. Walker,et al.  Relationships of Soil Acidity and Air Temperature to the Wind and Vegetation at Prudhoe Bay, Alaska. , 1979 .

[4]  J. M. Martín,et al.  Outflow of trace metals into the Laptev Sea by the Lena River , 1996 .

[5]  R. Wollast,et al.  Ocean margin processes in global change. , 1991 .

[6]  F. Elbaz-Poulichet,et al.  Preliminary assessment of the distributions of some trace elements (As, Cd, Cu, Fe, Ni, Pb and Zn) in a pristine aquatic environment: The Lena River estuary (Russia) , 1993 .

[7]  Douglas L. Kane,et al.  Hydrologic and thermal properties of the active layer in the Alaskan Arctic , 1991 .

[8]  J. Headley,et al.  Concentrations of Cd, Pb, Zn and Cu in Pristine Wetlands of the Russian Arctic , 1997 .

[9]  C. Guay,et al.  A survey of dissolved barium in the estuaries of major Arctic rivers and adjacent seas , 1998 .

[10]  A. Hershey,et al.  The biogeochemistry and zoogeography of lakes and rivers in arctic Alaska , 1992, Hydrobiologia.

[11]  J. M. Martin,et al.  A reassessment of the Eurasian river input of water, sediment, major elements, and nutrients to the Arctic Ocean , 1996 .

[12]  T. Osterkamp,et al.  Estimates of permafrost thickness from well logs in northern Alaska , 1981 .

[13]  J. Braun,et al.  Major and trace elements associated with colloids in organic-rich river waters: ultrafiltration of natural and spiked solutions , 1999 .

[14]  P. Mccart,et al.  Classification of stream types in beaufort sea drainages between prudhoe bay alaska usa and the mackenzie delta northwest territories canada , 1975 .

[15]  C. Grant,et al.  Mineral composition of some drainage waters from Arctic Alaska , 1962 .

[16]  O. Pokrovsky,et al.  Iron colloids/organic matter associated transport of major and trace elements in small boreal rivers and their estuaries (NW Russia) , 2002 .

[17]  W. Fischer,et al.  Geology of the Arctic slope of Alaska , 1951 .

[18]  J. Martin,et al.  First data on trace metal level and behaviour in two major Arctic river-estuarine systems (Ob and Yenisey) and in the adjacent Kara Sea, Russia , 1995 .

[19]  R. Robinson,et al.  Chemical and physical weathering of fluvial sands in an Arctic environment; sands of the Sagavanirktok River, North Slope, Alaska , 1997 .

[20]  B. Peterson,et al.  Water and sediment export of the upper Kuparuk River drainage of the North Slope of Alaska , 1992, Hydrobiologia.

[21]  S. Cabaniss,et al.  Copper binding by dissolved organic matter: I. Suwannee River fulvic acid equilibria , 1988 .

[22]  M. Meybeck.  Carbon, nitrogen, and phosphorus transport by world rivers , 1982 .

[23]  H. J. Walker,et al.  Suspended Load in the Colville River, Alaska, 1962 , 1967 .

[24]  G. Kling,et al.  The character and bioactivity of dissolved organic matter at thaw and in the spring runoff waters of the arctic tundra North Slope, Alaska , 1998 .

[25]  James P. McNamara,et al.  An analysis of streamflow hydrology in the Kuparuk river basin, Arctic Alaska : A nested watershed approach , 1998 .

[26]  S. Nakashima,et al.  Determination of trace elements in sea water by graphite-furnace atomic absorption spectrometry after preconcentration by tetrahydroborate reductive precipitation , 1988 .

[27]  R. Parkinson.  Genesis and Classification of Arctic Coastal Plain Soils, Prudhoe Bay, Alaska , 1978 .