CS13 Environmental Ecotoxicology
Date: Friday, June 14, 2002
Time: 9:15:00 AM
Location: Esquimalt
 
LuiderCD, University of Northern British Columbia, Prince George, Canada, cluider@hotmail.com
Curtis, P, J, Okanagan University College, Kelowna, Canada, JCurtis@ouc.bc.ca
Playle, R, C, Wilfrid Laurier University, Waterloo, Canada, rplayle.wlu.ca
 
EFFECT OF HYDROLOGIC RESIDENCE TIME ON COMPLEXATION OF COPPER BY DISSOLVED ORGANIC MATTER (DOM): COMPARISON WITH ALLOCHTHONOUS AND AUTOCHTHONOUS END MEMBERS
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Dissolved organic matter (DOM) is a primary regulator of trace metals in aquatic systems. However, DOM is degraded and transformed over time. The degree of DOM degradation in aquatic systems is dependent on hydrologic residence time (HRT). The objective of this research was to investigate changes in the copper complexing properties of DOM as a function of cumulative hydrologic residence time (CHRT). Furthermore, the copper complexing properties of allochthonous and autochthonous sources of DOM were compared. The copper complexing properties of DOM were investigated by titrating concentrated samples of DOM with Cu(II) (pH=6) and measuring free ionic copper with an ion selective electrode (ISE). Conditional stability parameters (K1, K2) were calculated from the titration data using a two-ligand Langmuir Isotherm. The Log(K1) values ranged from 7 to 13 and were inversely correlated to CHRT (r2 = 0.96). Furthermore, the Log(K1) value for autochthonous DOM was approximately 5-6 orders of magnitude less than allochthonous DOM. These results support two conclusions. First, that the copper complexing properties of DOM in aquatic systems are dependent on CHRT. Second, that the copper complexing properties of allochthonous DOM in aquatic systems begin to resemble autochthonous sources of DOM over time.