PARENT SESSION
PT5 - Fate & Effects of Metals: Aquatic Biology
Tuesday, 19 November 2002
8:00 AM to 6:30 PM
Exhibit Hall

(P622) Aquatic macroinvertebrates in blackwater streams of the southeastern U.S.: Toxicity of copper and moderating effects of DOM.

Duxbury, Craig^*,1, DeBusk, Thomas², ¹ WDI R&D, Lake Buena Vista, FL, USA² Azurea, Inc., Rockledge, FL, USA

ABSTRACT- Copper can be extremely toxic to aquatic organisms. However, the toxicity of copper in aqueous systems is dependent on multiple factors including concentrations of hardness and dissolved organic matter (DOM), constituents that can influence metal speciation. Water quality standards for copper are often based solely on the amount of calcium hardness in the water,even though it is recognized that dissolved organic matter also moderates the toxicity of copper. Little is known about the sensitivity to copper of native aquatic organisms in southeastern United States subtropical streams containing high DOM. . We therefore performed this study to characterize the sensitivity of a suite of native organisms to copper. We conducted a series of bioassays ranging from single taxa tests performed in the laboratory, to in situ community-level evaluations. We found that the toxicity of copper to native aquatic organisms in waters containing 25 to 60 mg/L TOC was significantly reduced. We also found that native aquatic organisms living in these high DOM waters were tolerant of copper concentrations several orders of magnitude greater than the Florida state water quality standards.

Key words: copper, aquatic macroinvertebrates, dissolved organic matter, toxicity