
TY  - JOUR
A1  - Hawke, DJ 
A1  - Hunter, KA 
T1  - Dissolved trace metal speciation in the Manuherikia River, Central Otago, New Zealand
JF  - Marine and Freshwater Research
JO  - Mar. Freshwater Res.
Y1  - 1992
VL  - 43
IS  - 6
SP  - 1381
EP  - 1391
KW  - 
UR  - https://doi.org/10.1071/MF9921381 
N2  - The inorganic speciation of the trace metals Cu, Ni, Cd, Zn and Pb has been calculated for the pristine, subalpine Manuherikia River. Temperature, pH, ionic strength and major-ion composition were found to be important controls on the free-ion activity of trace metals. Metal -CO3-2 species were the most important complexes for Pb, Cu and Ni. The metal-HCO3- species was most important for Cd, and Zn was intermediate. Ni, Zn and Cd were present mainly as the free divalent ion, whereas Pb (up to 81% complexed) and Cu (up to 70% complexed) were strongly affected by ionic interactions. Free-ion activities of Cu2+ and Pb2+ were essentially constant along the length of the river despite significant increases in total dissolved-metal concentrations. Thus, for these metal ions, total dissolved concentrations are a poor indicator of biological availability. 
ER  -

